Position water temperature sensor in engine .... Structure of the thesis In order to achieve the mention objectives, the thesis was organized with the following contents: Chapter 1: Over
OVERVIEW
Reasons to choose the topic
In today's rapidly evolving technological landscape, the integration of air conditioning systems with Electronic Fuel Injection (EFI) engines is becoming increasingly prevalent
By focusing on this topic, the project aligns with current industry trends and technological advancements.The topic bridges the gap between mechanical engineering (EFI engines) and thermodynamics (air conditioning systems) This interdisciplinary approach offers a holistic learning experience, allowing for a comprehensive understanding of both systems and their integration
Developing a teaching model for a combined air conditioner and EFI engine system provides an invaluable educational resource Such a model can serve as a practical tool for students and professionals alike, facilitating hands-on learning and research opportunities As the automotive and HVAC industries continue to prioritize sustainability and efficiency, understanding the intricacies of combined systems becomes crucial This project offers insights into optimizing performance, reducing emissions, and enhancing energy efficiency
The restoration and research aspects of the project necessitate innovative thinking and problem-solving skills Addressing challenges related to system integration, performance optimization, and troubleshooting will foster creativity and critical thinking abilities Choosing a topic that resonates with personal interest and passion enhances motivation, engagement, and commitment For individuals intrigued by automotive technology, thermodynamics, or interdisciplinary projects, this topic offers a fulfilling and rewarding experience
In summary, selecting the topic of "Restoration and Research on a Combined Air Conditioner and EFI Engine System Teaching Model" for the graduation project offers a blend of relevance, educational value, practical application, and career opportunities By exploring this interdisciplinary field, students can contribute to technological advancements, address industry needs, and cultivate essential skills for future endeavors
Purposes of research
General purpose: theoretical research on engine control systems and air conditioning systems, thereby diagnosing and finding ways to restore the system to optimal and synchronous operation.
Object of research
Teaching model of automatic air conditioning system combined with fuel injection engine Model: EFI MP ENGINE - 07
Figure 1.2 Control Panel Of Teaching Model
Scopes of research
− Investigate the individual components of both the air conditioning system and the electronic fuel injection (EFI) engine
− Consider the challenges and requirements to integrate these two systems seamlessly
− Evaluate compatibility issues, interface design considerations, and optimization techniques to ensure efficient operation
Performance analysis: Conduct comprehensive performance evaluation of the combined system under various operating conditions
− Explore the thermodynamic principles that govern air conditioning system operation in the context of the EFI engine environment
− Analyze control systems, sensors and actuators responsible for regulating temperature, airflow, fuel supply and other important parameters
− Analyze and improve engine speed according to modes when turning on or off the air conditioning system.
Research method
Conduct a comprehensive review of existing literature, academic literature, patents and industry reports related to combination air conditioning systems and EFI engines
Identify key theories, methods, technologies, and best practices relevant to the scope of the study
Synthesize findings from literature sources to establish a foundational understanding, evaluate current knowledge, and identify gaps or opportunities for further research
The study uses simulation tools to simulate the shape of the teaching model after being rebuilt.
Target of research
Through research, our team focuses on learning about the engine control system and car air conditioning system From there, solve problems related to recovery and improve performance for the entire system
Structure of the thesis
In order to achieve the mention objectives, the thesis was organized with the following contents:
Chapter 2: Overview of 2NZ-FE Engine
Chapter 4: Automobile Air Conditioning System
Chapter 5: Automatic Air Conditioning Camry 2002 System
Chapter 6: Construction of Teaching Model
OVERVIEW OF 2NZ-FE ENGINE
Introduction to 2NZ-FE engine
Engine Type 4 Cylinders, In-line, 16-valve DOHC with
Acceleration time from 0-100km/h 10 seconds
Fuel system EFI (Electronic Fuel Injection)
Table 2.1 Specifications of the 2NZ-FE engine
+ Air distribution system: Powerful engine with dual camshafts and Toyota's famous VVT-i system equipment helps the engine achieve higher capacity, save fuel, and achieve higher efficiency in different conditions different roads and environmental protection
• Intake manifold made of plastic
• ETCS-i (Electronic Throttle Control System intelligence)
Figure 2.4 Electronic Throttle Control System intelligence
• Exhaust manifold and exhaust pipe made of stainless steel
• Two sets of TWC - exhaust filter with 3 TWC components: Ultra-thin baffle, installed high-quality TWC filter element, helps filter very clean commune air
• 12-hole injector, fuel cut-off control when airbag is activated
• The modular fuel pump includes an activated carbon filter installed in the fuel tank to save space in the engine compartment
+ Cooling system: Maintenance intervals are extended due to the use of Toyota's super durable coolant (SLLC)
+ Charging system with compact, rod-type generator
+ Cooling fan control system with two Hi and Low modes
+ Cranking hold: As soon as the power switch is turned to the Start position, this function will control the motor to start without having to hold your hand in the START position
Details are tightened Kgf-cm
Throttle position sensor x Air throat 20
Idle speed control valve x Air throat 38
Air filter cover assembly x Air filter mounting bracket 80
Air filter inlet pipe No 2 x Vehicle body 76
Intake pipe x Cylinder cover assembly 306
Cylinder cover number 2 x Cylinder cover assembly 71
Standard fuel pressure 3.1 - 3.5 kgf/cm 2
Fuel pressure after 5 minutes of shutdown 1.5 kgf/cm 2 or higher
Less than 1 drop in 12 minutes
Fuel pump assembly, resistance at 20°C 0.2 - 0.3 Ώ
Details are tightened Kgf-cm
Cylinder cover assembly x Cylinder cover assembly 102
Ignition coil No 1 x Cylinder cover 92
Fuel line bend catch plate x Fuel tank 61
Filter tube assembly below fuel line x Fuel tank 36
Fuel tank assembly x Vehicle body 326
Handbrake cable assembly number 3 x Vehicle body 55
Handbrake cable assembly 2 x Vehicle body 55
Rear exhaust pipe section x Front exhaust pipe 326
Front exhaust pipe section x Exhaust manifold 438
Front floor suspension beam x Vehicle body 199
How to check: close doors B and C, then apply vacuum to A
How to check: close door C, then apply vacuum to A
Air comes out from door B
How to check: close door C, then blow compressed air into A
Air comes out from door B
How to check: Blow compressed air into A
Air comes out from door B and C
Vacuum transfer valve according to the pulse factor, resistance at 20°C 27 – 33 Ώ
Mechanical structure of the engine
The slack in the new drive belt
For fan and generator, pressure 10 kgf
For pump and power steering
The slack in the old drive belt
11.0 - 13.0 mm 11.0 - 13.0 mm The tension in the new drive belt
For fan and generator, pressure 10 kgf
For pump and power steering
The tension in the old drive belt
No-load speed of Automatic Transmission 700 ± 50 rpm
Difference in compression pressure between cylinders 1.0 kgf/cm 2
Details are tightened Kgf-cm
Camshaft bearing cover No 2 x Cylinder cover 129
Camshaft bearing cover No 1 x Cylinder cover 235
Ignition Coil No 2 x Cylinder cover 92
Engine mount No 1 x Cylinder cover 408
Oil pressure switch x Engine body 150
Water temperature sensor cam x Machine body 204
Oil dipstick guide x Engine body 92
Water pipe bypass number 2 x Engine body and cylinder cover 92
Exhaust pipe insulation board x Exhaust pipe 82
Camshaft oil control valve x Cylinder cap 76
Crankshaft position sensor x Oil pump assembly 76
Crankshaft chain damper assembly x Crankshaft 1305
Cylinder lid x Cylinder lidFront exhaust pipe x Exhaust manifold 102
Crankcase oil drain plug x Crankcase No 2 382
Front exhaust pipe x Exhaust manifold 438
Details are tightened Kgf-cm
Oxygen sensor x Front exhaust pipe section 449
Front exhaust pipe section x Exhaust pipe 438
Front exhaust pipe section x Front exhaust pipe section 326
Front floor panel tie bar x Vehicle body 199
8.5 mm or higher Valve lift at 95°C
Water tank cap - Pressure opens the safety valve
Continuous circuit (Supply battery voltage to 1 and 2) 3-5
10K Ώ or higher (Supply battery voltage to 1 and 2) 10K Ώ or higher Less than 1 Ώ (Supply battery voltage to 1 and
Details are tightened Kgf-cm
Water pump x Oil pump assembly 113
Water pump pulley x Water pump 150
Water inlet line x Machine body 92
Bracket on water tank x Vehicle body 51
Bracket on water tank x Hood hook bracket assembly 51
No-load speed 0.3 kgf/cm 2
Details are tightened Kgf-cm
Oil pump assembly x Cylinder cover and engine body
Ignition Coil No 1 x Cylinder cover 92
Crankcase oil drain plug x Oil Cacre number 2 382
Right tripod mount x Oil pump assembly 561
Oil pressure switch x Engine body 153
Details are tightened Kgf-cm
Camshaft position sensor x Cylinder cover 82
Crankshaft position sensor x Head pump assembly 76
Continuous circuit (Supply battery voltage to 1 and 2) 3-5
Details are tightened Kgf-cm
Cover under the right engine x Vehicle body 51
Cover under the left engine x Vehicle body 51
Fan belt adjustment bar x Cylinder cover 112
Generator x Fan belt adjustment bar 189
VVT-i (Variable Valve Timing-intelligent System)
The VVT-i system is designed to control the intake camshaft within a range of 40 (of Crankshaft Angle) to provide valve timing that is optimally suited to the engine condition This results in optimal torque over the whole speed range, great fuel efficiency, and a decrease in exhaust pollutants
The engine ECU calculates ideal valve timing for each driving circumstance and controls the camshaft timing oil control valve using the engine speed signal, vehicle speed signal, and signals from the mass air flow meter, throttle position sensor, and water temperature sensor Furthermore, the engine ECU gets information from the crankshaft and camshaft position sensors in order to identify the actual valve timing and offer feedback control to achieve the target valve timing
Figure 2.7 A Block Diagram of a VVT-i System
2.2.2 Effectiveness of the VVT-i System
Increasing overlap to boost internal EGR and lower pumping loss
Increasing the intake valve close timing to improve volumetric efficiency
Improved torque in low to medium speed range
Delaying the intake valve closing timing to improve volumetric efficiency
Eliminating overlap to minimize blow back to the intake side causes lean burning and stabilizes the idling speed at fast idle
- Stopping the Engine reducing blow back to the intake side by eliminating overlap
Table 2.3 Effectiveness of the VVT-i System
This controller consists of the housing driven from the timing chain and the vane coupled with the intake camshaft
The oil pressure provided from the intake camshaft's advance or retard side path induces spinning in the VVT-i controller vane circumferential direction to continually adjust the intake valve timing
When the engine is turned off, the intake camshaft will be in its most retarded position to ensure startability
The lock pin prevents the VVT-i controller from moving in order to prevent a banging sound when hydraulic pressure is not applied immediately after the engine is started
2.2.3.2 Camshaft Timing Oil Control Valve
This camshaft timing oil control valve controls the spool valve position in accordance with the duty-cycle control from the ECM This allows hydraulic pressure to be applied to either the advance or retard side of the VVT-i controller When the engine is turned off, the camshaft timing oil control valve is in its most retarded position
Figure 2.9 Camshaft Timing Oil Control Valve
When the camshaft timing oil control valve is activated by the ECM's advance signals, the resulting oil pressure is applied to the timing advance side vane chamber, causing the camshaft to rotate in the timing advance direction
Figure 2.10 Timing Advance Direction of VVT-I System
When the camshaft timing oil control valve is activated by retard signals from the ECM, the resulting oil pressure is applied to the timing retard side vane chamber, causing the camshaft to rotate in the timing retard direction
Figure 2.11 Timing Retard Direction of VVT-I System
Once the target timing is reached, the valve timing is maintained by retaining the camshaft timing oil control valve in the neutral position unless the traveling condition changes
This keeps the valve timing at the correct target position and keeps the engine oil from running out when it isn't needed.
Lubrication system
Oil flows through an oil filter in the fully pressured lubrication circuit
The front of the cylinder block has an oil pump with a trochoid gear type that is directly operated by the crankshaft
To achieve outstanding serviceability, the oil filter is positioned diagonally downward from the side of the cylinder block
A camshaft timing oil control valve and a VVT-i controller are installed in the cylinder head and intake camshaft, respectively The engine oil powers this mechanism
Dry 4.1 (4.3, 3.6) with Oil Filter 3.7 (3.9, 3.3) without Oil Filter 3.4 (3.6, 3.0)
Figure 2.13 Oil Circuit of Lubrication System
Cooling system
The cooling mechanism operates on a pressurized, forced-flow system
Positioned on the water inlet housing is a thermostat equipped with a bypass valve, ensuring consistent temperature distribution within the cooling system
To minimize weight, an aluminum radiator core is employed
The engine coolant pathway takes a U-shaped route within the cylinder block for optimal flow
A singular cooling fan serves dual purposes, enhancing both cooling and air conditioning capabilities
The system utilizes TOYOTA's authentic Super Long Life Coolant (SLLC)
2.4.2 System diagram and engine coolant specifications
Engine Type TOYOTA genuine Super Long Life
Coolant Coolant (SLLC) or similar high quality ethylene glycol based non- silicate, non-amine, non-nitrite and non-borate coolant with long-life hybrid organic acid technology (coolant with long-life hybrid organic acid technology is a combination of low phosphates and organic acids.) Do not use plain water alone
First Time 100,000 miles (160,000 km) Subsequent Every 50,000 miles (80,000 km)
+ Pre-mixed SLLC is available for the U.S and Canadian models (which are 50% coolant and 50% deionized water and 55% coolant and 45% deionized water, respectively) Consequently, while adding or replacing SLLC in the car, no dilution is required
+ The interval for LLC (ever 40,000 km/24 months) should be applied if LLC and SLLC are combined.
Fuel system
The fuel returnless system is used to reduce evaporative emissions
A fuel tank made of multi-layer plastic is used
A fuel cut control is used to stop the fuel pump when the SRS airbag is deployed in a front or side collision
A quick connector is used to connect the fuel pipe with the fuel hose to realize excellent serviceability
A compact 12-hole type injector is used to ensure the atomization of fuel
The ORVR (On-Board Refueling Vapor Recovery) system is used
Figure 2.16 Fuel Pump and Components
The purpose of this technology is to lower the evaporative emission It is possible to stop fuel from returning from the engine area and stop the temperature inside the fuel tank from rising by combining the fuel filter, pressure regulator, fuel sender gauge, and fuel cutoff valve with the module fuel pump assembly, as demonstrated below
Ignition system
ADIS (Direct Ignition System) is used With one ignition coil per cylinder, the DIS in this engine is an independent ignition system By doing away with the distributor, the DIS guarantees ignition timing precision, lowers high-voltage loss, and realizes the overall reliability of the ignition system
The ignition coils are incorporated with the spark plug covers, which attach to the spark plugs To make the system simpler, the igniters are enclosed as well
Long-reach type iridium-tipped spark plugs are used
Figure 2.19 Ignition Coil with Igniter
Iridium-tipped spark plugs of the long-reach kind are utilized
The portion of the cylinder head where the long-reach spark plugs are installed can be made thicker As a result, the water jacket can be expanded in the vicinity of the combustion chamber, improving cooling efficiency
To achieve a maintenance-free functioning of 100,000 kilometers (62,500 miles), iridium-tipped spark plugs are utilized
The same ignition performance as the platinum-tipped type spark plug has been achieved, along with exceptional durability, by creating an iridium center electrode
ENGINE CONTROL SYSTEM
Engine control system diagram
Mass Air Flow Meter Intake Air Temperature Sensor
Ignition Coil with Igniter Injector
SFI No.1 INJECTOR No.2 INJECTOR No.3 INJECTOR No.4 INJECTOR
IGNITION COIL with IGNITER SPARK PLUGS
CAMSHAFT TIMING OIL CONTROL VALVE
A/F SENSOR & OXYGEN SENSOR HEATER CONTROL
Figure 3.1 Engine control system diagram
STATER CONTROL STARTER RELAY ACC CUT RELAY
Layout of Main Components
Figure 3.2 Layout of Main Components
( Built-in Intake Air Temperature Sensor )
Vent Valve Leak Detection Pump Canister Pressure Sensor
Main components of Engine Control System
The main components of the 2NZ-FE engine control system are as follows:
The ECM ideally adjusts the SFI, ESA, and IAC to fit the engine’s operating conditions based on the inputs provided by the sensors
This sensor, like the heated oxygen sensor, monitors the oxygen concentration in the exhaust output It does, however, measure the oxygen concentration in the exhaust emission in a linear fashion
This sensor monitors the concentration of oxygen in exhaust emissions by measuring the electromotive force created within the sensor
Flow Meter Hot-wire Type 1 This sensor includes a built-in hot-wire for detecting the intake air mass directly
Pickup Coil Type 1 This sensor measures the engine speed and identifies the cylinders
Type 1 This sensor is responsible for cylinder identification
This sensor uses an inbuilt thermistor to monitor the temperature of the engine coolant
Thermistor Type 1 An inbuilt thermistor in this sensor senses the temperature of the intake air
This sensor detects an incidence of engine knocking indirectly through vibration of the cylinder block generated by engine knocking
Non-contact Type 1 This sensor detects the angle at which the throttle valve opens
The amount of pedal effort delivered to the accelerator pedal is detected by this sensor
The injector is an electromagnetically controlled nozzle that injects fuel in response to ECM signals
Table 3.1 Main components of Engine Control System
Input signals
3.4.1 Mass Air Flow Sensor (MAF)
Figure 3.3 Mass Air Flow Sensor (MAF) Shape
Mass Air Flow Sensor - MAF is located between the air filter and intake manifold to determine the speed and volume of air entering the fuel injection system of the internal combustion engine
Figure 3.4 Mass Air Flow Sensor’s Location
Figure 3.5 Mass Air Flow Sensor’s Wiring Diagram
Mass Air Flow Sensor (MAF) is used in conjunction with the Intake Air Temperature sensor (IAT) that used to strictly control the rate of air entering the engine
The Mass Air Flow Sensor has a complex structure that helps provide signals for the ECU to calculate the basic fuel amount and advance ignition angle, increasing operating efficiency The structure of this part includes: a resistor, control circuit and heating wire
Mass Air Flow Sensor helps convert the amount of air passing through the sensor into a voltage signal This signal transformation can be based on changing the temperature of the sensor's internal components (hot-wire type sensor)
Signals from the sensor sent to the ECM help calculate the correct intake air flow So that, the engine can determine the fuel level to be injected and the ignition timing to ensure operating efficiency
- Step 1: When the engine is running, run at idle Plug in the OBD II diagnostic device, select read Fault Codes
+ Fault Code P0101: Mass Air Flow Sensor Circuit/Performance Malfunction ( go to step 2)
+ If no Fault Code Appears: Read Datalist in MAF to see the intake air flow: 200-271 g/s (go to step 4)
- Step 2: Check the voltage signal from the sensor sent to the ECU
Figure 3.6 Connection Port of MAF
VG = Mass Air Flow Meter
THA = Intake Air Temperature Sensor
+ Using a multimeter, turn on the VOM scale
Testing content Condition Standard value
Pin 3(VG) – Pin 2(E2) Engine ON 0.2V - 5V
Not Standards Replace MAF or Check again the System
- Step 3: Check the connection of the connectors from the sensor to the ECU, check for short circuit or open circuit, then go for replacement
+ Disconnect the battery's electrical connection
+ Using a multimeter, turn on the OHM scale
Testing Content Standard value Pin 3 (VG) – 118B (VG) Under 1Ω Pin 2 (E2G) – 116B (E2G) Under 1Ω Pin 4 (THA) – 65B (THA) Under 1Ω
Not Standards Repair the wire from the connector to the ECU
- Step 4: Remove the MAF, then clean it, and reattach it to the system Start the engine, use the diagnostic device, clear the Fault Codes and check the Air Flow datasheet
3.4.2 Engine Coolant Temperature sensor (ECT)
Figure 3.7 Engine Coolant Temperature sensor’s shape
The Engine Coolant Temperature Sensor is mounted on the engine body
Figure 3.9 ECT sensor’s Wiring Diagram
The ECT sensor detects the engine coolant temperature using a thermistor In terms of structure, it is a semiconductor with the standard working negative thermistor value of the sensor being 80°C The coolant temperature sensor has 2 terminals, THW and ETHW
The power supply for the sensor is 5V supplied through a resistor When the coolant temperature changes, the resistance of the rheostat also changes The microprocessor receives voltage at the THW terminal to determine the engine's working temperature The
ECU receives coolant temperature signals to control fuel injection volume, ignition advance timing, and idle speed control according to coolant temperature When the coolant temperature is below 80°C, the ECU will increase the idle speed, increase the amount of fuel injected, and increase the ignition advance angle
Figure 3.10 Connection Port of ECT
- Step 1: When the engine ON Plug in the OBD II diagnostic device, select read Fault Codes
+ Fault Code P0115: “Engine Coolant Temperature Sensor Circuit Malfunction” In particular, the voltage in the circuit exceeds the allowable limit by 0.14V to 4.91 V (corresponding to the temperature range from -40 °C to +140 °C)
+ Fault Code P0116: Engine Coolant Temperature Circuit Range/Performance
+ Fault Code P0117: “ECT Sensor Circuit Low Input” This fault occurs when a voltage below 0.14V is supplied from the sensor to the ECU, which is the threshold value (the value of the critical voltage may vary)
+ Fault Code P0118: “ Engine coolant Temperature senser 1 Circuit High” when the sensor output voltage exceeds 4.91 V for 0.5 seconds or more Most likely there is an open circuit in the sensor
+ No error code appears Read Datalist to see coolant temperature: 80ºC when starting the engine (go to Step 4)
- Step 2: Check the sensor input signal sent to the ECU
+ When Key ON, use Multimeter to measure 2 pins of C19, has voltage : 5V
- Step 3: Check the wire connecting the sensor to the ECU
+ Disconnect the battery's electrical connection
+ Using a multimeter, turn on the OHM scale
Testing Content Standard Value Pin 1 – 96B (ETHW) Under 1Ω Pin 2 – 97B (THW) Under 1Ω Result:
Standards Go to step 4 Not Standards Repair the wire from the connector to the ECU
- Step 4: Check whether the resistance of the coolant temperature sensor changes with temperature
+ Remove the sensor from the engine
+ Measure the initial resistance of the sensor by measuring the two terminals of the sensor
• In case the sensor tail is dipped in water: Resistance has a value of 4.8 - 6.6 Ω
• In case of using fire to burn the sensor's tail: Resistance has a value of 0.2 - 0.3 Ω
+ You can measure on the control panel of the model when starting the engine to see the change in resistance with temperature
- Step 4: Remove the IAT, then clean it, and reattach it to the system Start the engine, use the diagnostic device, clear the Fault Codes and check the Intake Air Temperature datasheet
The Knock sensor is usually mounted on the cylinder body, below the intake manifold or attached to the engine block
Figure 3.12 Location of Knock Sensor
Figure 3.13 Knock Sensor’s Wiring Diagram
The Knock sensor is made of a piezoelectric material, quartz crystal When there is a knocking sound, the sensor with quartz crystal will automatically generate voltage and send it to the ECU
The Knock Sensor's mission is to measure the knocking sound in the engine and send a voltage signal to the ECU, from which the ECU will receive and analyze that signal to adjust the ignition angle to reduce knocking (Normally the knocking sound is caused by impact of mechanical parts in the engine due to detonation)
• If an error occurs, the ignition angle is the latest
• If detonation is detected, the ECU will adjust to reduce the ignition advance angle
When the engine is running, for some reason there is a knocking sound (self-detonation, overheating of the engine, mechanical impact ) the sensor will create a voltage signal sent to the ECU and the ECU will regulate the engine Adjust the ignition delay to reduce the knocking sound
Specifically: The piezoelectric elements of the detonation sensor are designed to have a size with a natural frequency that coincides with the vibration frequency of the engine when detonation occurs to create a resonance effect (f = 6KHz - 13KHz )
Thus, when the engine detonates, the quartz crystal will experience the greatest pressure and generate a voltage This voltage signal has a value of less than 2.5V Thanks to this signal, the engine ECU recognizes the phenomenon of detonation and adjusts to reduce the ignition angle until detonation no longer occurs The engine ECU can adjust the ignition timing again
Figure 3.14 Connection Port of Knock Sensor
- Step 1: When the engine ON Plug in the OBD II diagnostic device, select read Fault Codes
- Step 2: Check the wire and connector from the sensor to the ECU
+ Measure the continuity of 2 connectors P1 and C20
Not Standards Repair the wire from the connector to the ECU
- Step 3: Check the input voltage of the sensor’s connectors
+ Disconnect the connector P1 of knock sensor
+ Use Ohmmeter measure 2 pins of Sensor
Output Signals
3.5.1.1 Shape of Bobine and Igniter
Figure 3.32 Ignition Coil of Toyota
Figure 3.33 Location of Ignition System
Figure 3.34 Wiring Diagram of Ignition System
The ignition system of the 2NZ-FE engine is a direct ignition system (DIS) Bobine and ignition IC are installed directly at the top of the spark plug to form a detailed assembly
Due to such a structure, there is no high-voltage wire in the ignition system, thus reducing energy loss, and increasing the ability to anti-interference ability This system has several advantages:
− The ignition advance angle is optimally controlled for each engine operating mode
− The power intake angle is always adjusted according to the motor speed and according to the motor voltage signal, ensuring the secondary voltage has a high value at all times
− The engine is easy to control, idles smoothly, saves fuel and reduces toxic emissions
− The engine’s power and dynamic characteristics are significantly improved
− Capable of anti-knock control for the engine
So that, the Direct Ignition System’s structure is similar to other electronic ignition systems, also including main parts: spark plug, bobine, ignition coil This ignition system is different from the conventional ignition system in that it does not have a distributor, uses each Ignition Coil and ignition coil for each spark plug, these Ignition Coils and coils are located right on each spark plug
To control the ignition system to operate well in all engine modes, the ECU receives signals from sensors, compares them with programmed data, calculates and adjusts to produce ignition control signals Intake air flow and engine rpm sensor are two parameters that determine basic ignition timing Signals from other sensors such as coolant temperature sensor, knock sensor, intake air temperature sensor to determine correct ignition timing
Ignition control is completely controlled by the ECU by sending IGT 1 (IGT 2, IGT 3, IGT 4) signals to the correct IC of the machine in the correct working order The IC will control the current through the primary coil of the ignition engines to match the engine’s operation On the ignition system, there is also an IGF feedback signal transmission line Thanks to the ECU feedback signal, the damage to the ignition system can be determined If the ignition system is damaged, the ECU controls fuel cut-off to avoid fuel loss and ensure environmental pollution
System specifications and location of IG Bobine clusters (viewed from the electrical jack)
Figure 3.35 Connection Port of Ignition System
- Step 1: When the engine ON Plug in the OBD II diagnostic device, select read Fault Codes
- Step 2: Check the power supply for the ignition coil and the signal pin (IGF) sent from the coil to the ECU
+ Use a multimeter to measure the 2 pins on the sensor by using the VOLT scale
Pin 1 (B+) – Pin 4 (GND) 11 – 12V Pin 2 (IGF) – Pin 4 (GND) 4.5 – 5V
Standards Go to step 3 Not Standards Check the Power supply
+ Use a multimeter to measure by using the OHM scale
Pin 2 (IGF) – 81B (IGF) Under 1Ω Pin 3 (IGT1) – 85B (IGT1) Under 1Ω Pin 3 (IGT2) – 84B (IGT2) Under 1Ω Pin 3 (IGT3) – 83B (IGT3) Under 1Ω Pin 3 (IGT4) – 82B (IGT4) Under 1Ω
Not Standards Replace wire from connector to ECU
- Step 4: Clean the Bobine and Spark plug, observe the gap and color of the spark plug then reinstall it into the engine Start the engine, clear errors on the diagnostic machine and check again Fault codes
3.5.2 Electronic Throttle Control System-intelligent (ECTS-i)
The automatic throttle opening control is through the throttle control motor, which is a
DC electric motor with very high sensitivity and low energy consumption, installed right on the side of the throttle body and is connected to the throttle control lever through reduction gears The installation location of the throttle control motor is shown in below figure:
Figure 3.36 Electronic Throttle Control System-intelligent (ECTS-i)
The ECU receives signals from the accelerator pedal position sensor, controlling the throttle control motor to open and close the throttle via the reduction gear set Throttle opening is always determined by the throttle position sensor, this signal is fed back to the ECU Based on this feedback signal, the ECU determines the throttle opening and controls the throttle opening when necessary in accordance with the accelerator pedal position Because the throttle control is completely automatic, the accelerator pedal position is converted into pulse signals and sent to the ECU to control the throttle via the motor, so no cables are used
Figure 3.37 Throttle Position Sensor’s Wiring Diagram
Figure 3.38 Connection Port of Throttle body
- Step 1: Use a diagnostic device to connected to the engine's OBD-II connector
- Step 2: Checking wires from sensor to ECU
+ Do not supply power to the engine
+ Use Multimeter with OHM scale:
Pin 1 (M+) – 41B (M+) Under 1Ω Pin 2 (M-) – 42B (M-) Under 1Ω Pin 3 (E2) – 91B (ETA) Under 1Ω Pin 4 (VTA2) – 114B (VTA2) Under 1Ω Pin 5 (VC) – 67B (VCTA) Under 1Ω Pin 6 (VTA1) – 115B (VTA1) Under 1Ω
Not Standards Replace the wires
- Step 3: Checking Power supply from ECU send to Throttle
+ Use a multimeter to measure with VOLT scale
Standards Go to step 4 Not Standards Check power supply to ECU
- Step 4: Checking power supply of 2 jacks main & support
+ Use a multimeter to measure with VOLT scale
Pin 6 (VTA) – GND Unpress and press all the way down the accelerator
Pin 4 (VTA2)-GND Unpress and press all the way down the accelerator
- Step 5: Clean the throttle valve with specialized cleaning solution Start the engine, delete the fault codes and check the datalist again
Figure 3.39 Fuel Injection System’s Wiring Diagram
The fuel injectors are located on the cylinder head cover They inject fuel into the cylinder according to signals from the ECM
Figure 3.41 Connection Port of Injector
- Step 1: Use a diagnostic device to connected to the engine's OBD-II connector
- Step 2: Checking power supply to injector
+ Disconnect 4 injectors and check each injector
+ Use multimeter to measure with VOLT scale
Standards Go to step 3 Not Standards Go to step 4
- Step 3: Checking wires of connector
+ Disconnect the battery's electrical connection
+ Use multimeter to measure with OHM scale
Pin 2 injection 1 – 108B (#10) Under 1Ω Pin 2 injection 2 – 107B (#20) Under 1Ω Pin 2 injection 3 – 106B (#30) Under 1Ω Pin 2 injection 4 – 105B (#40) Under 1Ω -Result:
Standards Go to step 4 Not Standards Replace the wires
- Step 4: Checking relay IG2 and fuse 15A AM2
+ Check if the fuse is blown or not by measuring continuity
+ Remove relay IG2 to check:
• Measure the resistance of the 2 relay coil pins corresponding to pin 2 and pin 3
• The remaining 2 pins are 2 contact pins, because it is a normally open relay so the 2 pins are not connected
• Check the operating status of the relay: Pins 1 and 2 provide power (+) and pin 3 connects to ground Hearing the "knock" sound means the contact is closed well
Measure the resistance of the two contact pins to be extremely large so it is a good relay
Not Standards Replace Relay and Fuse
+ Use milimetieespto measure directly 2 pin of injector with OHM scale
Standards Go to step 6 Not Standards Replace Injector
Attention: When replacing injectors, remember to buy the correct brand and have the injector code, remember to enter the code for the ECU to remember to give the injection signal
- Step 6: Clean the injector and install it in the engine, start the engine, use a diagnostic machine to clear the error
AIR CONDITIONING SYSTEM
Overview of car air conditioning systems
- The purpose of an air conditioning system is to maintain a car's interior temperature at a level that is safe for human health The system has the following modes of operation: dehumidification, ventilation, heating, and cooling
- Depending on the size of the area and the level of complexity needed for the cell, the air conditioning system can be basic or complicated, including all or part of the aforementioned functions
- 18 to 22 degrees Celsius, 40 to 60%, 0.1 to 0.4 m/s for ventilation, and less than 0.001 g/m^3 are the ideal parameters for interior temperature and humidity
- Heating mode: The manufacturer uses the engine coolant as it is heated by the engine and uses this heat to heat the air blown into the heating system At that time, the car had just started and did not have a heating mode and the climate in Vietnam was tropical so this mode was not utilized
Figure 4.2 Operating principle of the heater
- Air conditioning mode: Cooling air, we must first start the car and turn on the A/C signal on the A/C control unit That gas causes the compressor to operate and push the refrigerant through heat-resistant pipes to the evaporator The Evaporator is responsible for creating cold air and thanks to the outside air being sent into the evaporator by the fan blower Refrigerate the passenger compartment
Figure 4.3 Operating principle of the air cooling system
- The passenger compartment's air needs to be cool
- The air needs to be pure
- It is necessary to distribute cold air throughout the passenger cabin
- Dry, cold air with no humidity
The air conditioner in this kind is frequently installed on the dashboard The motorist feels a higher cooling effect than the air conditioner's capacity while using this form of air conditioning since the cold air is blasted directly in front of them The driver can experience the cooling impact since he can regulate the cold air outlet
Figure 4.4 Font style air conditoning
Figure 4.5 Rear style air conditoning
The air conditioning cluster on this model is housed in the car's rear trunk On the back of the rear seat are the cold air inlet and exit This type of air conditioner has the benefit of an air conditioner with a large cooling capacity and reserve cooling capacity since the air conditioner cluster is installed in the rear trunk where there is a huge area
Figure 4.6 Dual style air conditoning
The vehicle's front and back are blasted with cold air The car's interior has excellent cooling qualities that evenly distribute the temperature inside and produce a cozy microclimate
This method enables temperature control within the car through manual manipulation of switches or levers In addition, a lever or switch regulates the air volume, wind direction, and fan speed For instance, the air intake near the automobile or outside, the direction of the wind, and the fan control switch frequently utilized on trucks and cars built prior to the 19th century
Figure 4.7 A/C unit control manual Cadillac
Automatic control controls the desired temperature through the air conditioner (A/C amplifier Assembly) Air temperature is controlled automatically based on signals from sensors sent to the ECU For example: A/C room temperature sensor, ambient temperature sensor, solar sensor, cooler temperature senser
HVAC System
- The primary function of a heating, ventilation, and air conditioning (HVAC) system in car air conditioning is to cleanse and circulate air throughout the vehicle in addition to adding or removing unwanted heat from the passenger cabin The driver can control the operation of the HVAC system either automatically or manually
- HVAC is an abbreviation for Heating, Ventilation, and Air Conditioning The HVAC system of an automobile can be conceived of as a climate control system with three subsystems: [8]
- The primary purpose of the heating system is to provide heat all winter Heating the passenger compartment is a relatively easy task, considering the amount of waste heat produced by the engine This waste heat is absorbed by the oil and engine parts before being discharged into the exhaust system The engine cooling system is responsible for this We can use this source to generate heat for the passenger compartment
- Ventilation air serves to maintain a fresh interior for the car, replace stale air, prevent carbon monoxide from exhaust, and increase cabin pressure The air ducts allow outside air to be filtered inside the passenger compartment by collecting dust and pollen particles before they enter
A vapour compression refrigeration system offers cooling for air conditioning To chill, purify, and dehumidify air, the vehicle air conditioner integrates the refrigeration system with an air-distribution system and a temperature-control system
- The automobile compartment is heated for a number of reasons, including:
+ Higher temperature of outside air
- The amount of heat absorbed is dependent upon:
+ Position of sun and intensity of solar radiation
+ Variation of light and shadow
+ The cabin passengers also contribute to heat [8]
Components of the air conditioning system
The components of a car air conditioning system are nearly identical to those of a room air conditioner, but because of the small space, many design changes have been made to allow for easy installation in the vehicle as well as system maintenance and repair
Figure 4.9 The operation and parts air conditoner system
- It is also known as the heart of the AC system In order for the refrigerant to continue flowing through the condenser, the compressor applies more pressure to the refrigerant, converting it from vapor to liquid
- The engine's crankshaft powers the car air conditioning system's compressor via a belt drive
- Scroll compressors are rotary type compressors They are a positive displacement machine that relies on the compression action supplied by two intermeshing spiral-shaped scrolls, one fixed and one revolving
- "Scroll compressors are orbital motion, positive-displacement machines that compress with two interfitting, spiral-shaped scroll members," states ASHRAE's HVAC Systems and Equipment Handbook
- The following parts are commonly found in vehicle air conditioning scroll compressors:
Scrolls, Casing, shaft, bearing, refrigerant chamber, rubber seal, balancing spring, magnetic clutch and pressure valve [8]
Figure 4.10 Parts of scroll compressor
- It is a positive displacement compressor with a hermetic motor that rotates in an orbit A centrifugal pump buried in the oil sump supplies oil to lubricate the motor shaft bearings and the circling scroll journal bearings
- To accomplish the gas compression, two interfitting, matching spiral-shaped scrolls are joined in a 180-degree out-of-phase configuration
- An involute spiral that is constrained by a base plate on one end of the vane and open at the other is called a scroll.A sequence of gas pockets is created between the two mating spirals when the two scrolls are positioned together
- Of the two scrolls, one is fixed and held stationary, while the other, called the orbiting scroll, is designed to circle around a fixed spot on the stationary scroll without rotating (See Fig 4.11)
Figure 4.11 Arrangment of fixed and orbiting scroll
- The scroll's flanks maintain contact while the contact spots gradually move inward
- The relative angle and motion of the two scrolls are maintained and prevented by interconnecting connections
- In order to form a gas seal at the mating surface, the scroll tips are fitted with seals that act as piston rings and ride on the surface of the opposite scroll
- The outside edge of the scroll assembly is where the suction gas is sucked in, and the port in the middle of the stationary scroll is where it is released
- Because of the offset between the centers of the scroll journal bearing and the motor shaft of the drive assembly, the driven scroll moves eccentrically, or in circles
As the orbiting motion continues, the relative movement of the orbiting and fixed scrolls leads the scroll to move in the direction of the assembly's discharge port, repeatedly reducing and rising the gas pressure The mated scrolls form gas pockets as a result of the orbiting motion
- First shaft rotation (Suction phase):
+ As the shaft spins, the circling scroll orbits and opens the suction port, allowing space to be created between two scrolls
+ The scroll lateral surfaces meet again at the end of the first revolution, generating gas pockets [Refer Figure 4.13]
Figure 4.13 First revolution of shaft
- Second shaft revolution (Compression phase):
+ Additional shaft rotation; by sealing suction gas in pockets of given volume at the outer periphery of the scrolls; and the volume of the gas pockets is progressively reduced and the gas is compressed [Refer Figure 4.14]
+ At the completion of the second revolution produces maximum compression of gas occurs [Refer Figure 4.14]
Figure 4.14 Second revolution of shaft
+ The pressurized gas is discharged through the discharge port during the third rotation of the shaft The volume of the gas pockets is decreased to zero by the end of the third revolution, squeezing the residual gas from the scrolls
+ In the entire cycle, the three phases of intake, compression, and discharge occur in a continuous succession [Refer Figure 4.15] [11]
Figure 4.15 Third revolution of shaft
One of scroll air compressors' best qualities is that it operates more silently than piston and screw air compressors Despite this, scroll air compressors are less common because of their around 45% greater cost more well-liked
4.3.2.1.2 The connection of the compressor to the moving parts of the engine
A single serpentine belt drive or several belt drives connected to the engine crankshaft power compressors When a belt has a large distance between pulleys, a small idler pulley is typically used in conjunction with a belt adjusting device to absorb vibrations from the belt
Figure 4.16 Two types connection of compressor belt
A mechanism for transferring power between an automobile's engine and air conditioner compressor is the vehicle ac compressor magnetic clutch It is made up of three parts: the drive disc assembly (sometimes called a sucker or pressure plate assembly), the coil assembly, and the belt disc assembly
- The clutch pulley: is driven by the drive belt any time the engine is running It spins on the pulley bea
- The clutch coil: The compressor clutch coil is simply a large coil of copper wire When the driver requests AC, the system provides power to the clutch coil, thereby generating a magnetic field, which turn the pulley into a strong magnet
- The clutch plate: when it mates against the clutch body, it links to the AC compressor shaft and powers the compressor
The compressor shaft rotates when the clutch coil generates a magnetic field and draws part of the clutch plate up against the clutch body/pulley
The magnetic clutch consists of a stator (electromagnet), pulley, centering part and other parts The stator is mounted on the compressor's front body, and the centering unit and compressor shaft are attached simultaneously
4.3.2.2.3 Principle of operation of magnetic clutch
Overall Schematic of Air-conditioning Components and Controls
Figure 4.48 Schematic of Air-conditioning Components and Controls
Refrigeration Cycle
Figure 4.49 Air conditioning automatic system
2 Valve high pressure 7 Cooler themistor
5 Temperature sensor 10 Magnetic clutch compressor
- A basic refrigeration system is seen in the figure below, with all of the major parts sealed off with hoses and tubes holding the refrigerant The capacity of refrigerant to alter its physical characteristics when compressed is essential to the functioning of a refrigeration system
- In the figure above, note that the high-pressure side of the system extends from the outlet of the compressor to expansion valve The low-pressure side extends from the expansion valve back to the inlet of the compressor
- The process of removing heat from air involves four stages of the refrigeration cycle: compression, condensation, expansion, and evaporation.[8]
+ Compression - The gaseous refrigerant is compressed by the compressor thereby significantly increasing its pressure and temperature When the refrigerant gas is compressed and the pressure is increased, it becomes comparatively easier for arefrigerant gas to give off heat and liquefy (condense)
+ Condensation - The pressurized refrigerant vapour is pumped from compressor to condenser where it removes heat from the refrigerant This causes the refrigerant to change from high-pressure hot vapour into the warm liquid The heat is given off to outside air Condensation occurs at constant pressure
+ Expansion - The liquid refrigerant then passes an expansion valve where it losses pressure and changes its state to wet droplets Expansion occurs with no change in enthalpy
+ Evaporation - The wet droplets pass through the evaporator where it absorbs heat from the air This causes the refrigerant to change from a low-pressure cold liquid into a cold vapor (the latent heat of evaporation) The evaporation occurs at constant pressure The cycle continues.[8]
- In summary, heat is transferred from the refrigerant to the outside air in the condenser and absorbed by the refrigerant in the evaporator (cooling the air) In order to enable the cycle, the expansion device and compressor work together to control the refrigerant's pressure.Remember that even with more sophisticated centralized HVAC systems like
113 chillers, the fundamentals of the refrigeration cycle will never change The type of refrigerant used in a refrigeration system determines its operational characteristics
4.6 How Automotive Air conditioning work?
- The compressor runs and leads the refrigerant to the condenser (heater) when the engine is running and the electromagnetic clutch control circuit is closed At this point, the cooling fan cools the liquid refrigerant and causes it to release heat into the surrounding air
- The expansion valve is forced to open once the refrigerant has passed through the condenser A pressure decrease occurs behind the expansion valve as a result of the refrigerant passing through the throttle valve, a tiny cross-sectional area (drop compression)
- Heat is absorbed by the refrigerant when it is fed into the evaporator, or cooler Heat is transferred from the passenger compartment to the refrigerant through the condenser
- The temperature decreases as a result of the refrigerant's absorption of passenger heat For the subsequent cycle, the refrigerant re-enters the compressor
- To guarantee that the car's temperature stays constant at a predetermined level while it is in operation, the A/C control periodically turns the electromagnetic clutch on and off The low pressure branch and the high pressure branch are the two divisions of refrigerant pressure
+ The compressor's inlet valve and the refrigerant behind the expansion valve limit the low pressure branch
+ The compressor's output valve and the refrigerant directly in front of the expansion valve limit the high pressure branch
- The blower and the flowing cold air stream distribute cold air throughout the passenger compartment
AUTOMATIC AIR CONDITIONING CAMRY 2002 SYSTEM
Automatic Air Conditioning system
5.1.1 How to identify automatic systems
Automatic Air Conditioning system is activated by pressing the AUTO switch and adjusting the desired temperature Because of the ECU's automatic control function, the system will immediately adjust and maintain the temperature at the set level
5.1.2 The components of automatic Air conditioning system:
- Air vent mode servo motor
- Air mix control servo motor
Figure 5.1 Control components of automatic air conditioning systems
A/C control amplifier
- The control system consists of input sensors, switches, A/C amplifier (microcomputer) and outputs The relationship of these components is shown in the figure below:
Diagram wiring Air conditiong automatic system toyota camry 2002
Figure 5.3 Diagram wiring Air conditiong automatic system toyota camry 2002
System control method
- An electrical relay regulates the compressor's ON/OFF state Along with other control signals generated by the engine ECU, this kind of signal is relayed by the controller
- The following signals are sent out by the controller: Depending on the condition of the engine at the moment, the ECU can send signals back, enabling the compressor to run and initiating throttle correction
Figure 5.4 Diagram of controlling the compressor ON and OFF
5.4.2 Blower control motor ( using mosfet)
Figure 5.5 Circuit diagram Blower control fan with fan resistor (mosfet type)
- Battery (+) to fuse 50A (At this large current, to control high-speed fans, use a fuse with a high rating ) Relay 5 Pin (Open)
+ Pin 1 relay connect the power source to positive ( + ) to 10A fuse, Pin 2 connecting Pin 32 HR (A/C control assembly)
+ Pin 5 relay connected to the source through 50A fuse, Pin 4 Mass
+ Pin 3 connect the blower motor to positive and connecting pin 3 (+ B) Blower control motor
+ Pin mass blower motor with Pin 4 (VM) Blower control motor
+ Pin 1 (GND) Blower control motor connecting Mass
+ Pin 2 ( Si ) Blower control motor connect to Pin 31 (BLW) A/C control assembly, Pin is responsible for changing the fan speed
- Work: when the fan signal 1 step is turned on on the A/C control assembly, the positive power passes through the coil waiting for the signal of the HR pin with the ground beat to close the relay Pins 3 and 5 are connected Then the power + from the 50A fuse passes through relay pin 3 to supply the positive blower motor and feed the fan control circuit (mosfet type)
- When fan level 1 is pressed, a high voltage (3.8V) is output from the VM pin, causing the fan to rotate slowly And then decrease the voltage thanks to the A/C control unit
5.4.3 Idle speed controller (throttle compensation)
- When the engine is idling, The engine has little power Running the compressor will cause the motor to overheat This may cause the engine to stall or overheat; as a result, the engine speed needs to be automatically increased, called idle throttle speed control
- Electric throttle compensation: The engine control ECU receives the A/C ON switch signal from the A/C amplifier and opens the idle speed control valve Both the amount of air and fuel increases, helping to increase the engine speed to the appropriate value There are two types of electric throttle compensation: air bypass type and ISCV idle control valve type
Thermistor type: To avoid frost formation, a cooler temperature sensor is mounted adjacent to the evaporator to receive temperature signals from the unit The A/C amplifier receives the voltage signal that is created from the temperature change To avoid freezing, the controller turns off the air conditioner when the temperature falls to about 0ºC
Figure 5.7 Diagram of thermistor type defrost control system
5.4.5.1 Controls A/C closed when the medium pressure is unstable
- Identification of unusually low pressure Poor lubrication will result from letting the compressor run when there is not enough refrigerant in the refrigeration cycle or when there is no refrigerant in the cycle because of leaks or other issues can result in a jammed compressor Disconnecting the pressure switch is necessary to release the magnetic clutch when the medium pressure falls below the usual range, namely less than 0.2 MPa (2 kgf/cm2)
- Abnormally high pressure detected: When the condenser is not cooled sufficiently or when an excessive amount of refrigerant is loaded, the refrigerant pressure in the cooling cycle may be abnormally high The cooling cycle assemblies may be harmed by this Disengaging the magnetic clutch requires turning off the pressure switch when the refrigerant pressure exceeds 3.1 MPa (31.7 kgf/cm2)
Figure 5.8 Structure and schematic control pressure switch
The pressure switch is installed in the high pressure branch of the refrigeration system When this branch pressure is higher than specified, this signal controls the compressor to stop operating to avoid damage to the whole system
5.4.5.2 Detected that the compressor was stuck
Figure 5.9 Compressor drive system diagram
When the compressor drive belt jams, the electromagnetic clutch is disengaged and the compressor stops working to protect the belt
5.4.5.3 Controls A/C closed when engine temperature is high
Figure 5.10 Position water temperature sensor in engine
To lessen the burden on the motor and keep it from overheating, the water temperature switch detects high water temperatures and turns off the compressor
Figure 5.11 Diagram control radiator fan
- Cooling Fan Operation: The radiator fan is an electric motor controlled at different speeds When the cooling temperature is low, the fan control ECU does not work When the engine runs at high speed, the ECU lets the fan run at medium speed When the temperature is stable, the fan runs at maximum speed
- When the air conditioner is turned on, the radiator fan always rotates quickly Because turning on the A/C sends signals to the ECU, the additional load makes the ECU realize that the fan must be turned on continuously at high speed
- Relay No 1 and No 2 fan are located on the engine compartment fuse box
- Based on the signals from the engine coolant temperature sensor and the air conditioning control unit, the ECM regulates the cooling fan's operation in high fan
The cooling fan's speed is decreased when current is applied through a resistor to achieve low speed operation
- Cooling Fan Operation: The radiator fan is an electric motor controlled at different speeds When the cooling temperature is low, the fan control ECU does not work When
127 the engine runs at high speed, the ECU lets the fan run at medium speed When the temperature is stable, the fan runs at maximum speed
- When the air conditioner is turned on, the radiator fan always rotates quickly Because turning on the A/C sends signals to the ECU, the additional load makes the ECU realize that the fan must be turned on continuously at high speed
Figure 5.12 Cooling fan operation through ECT
When there is an A/C signal, then power is applied to the compressor and when the compressor is active, power is also applied to the coil of the condenser fan relay Closing the relay contact causes the condenser fan to rotate Therefore, the model has condenser fan control based on the compressor's magnetic clutch
Figure 5.13 Wiring diagram control of the condenser fan
CONSTRUCTION OF TEACHING MODEL
Mechanical design
6.1.1 Introducing Autodesk Inventor Professional software
Autodesk Inventor Professional is software for designing, prototyping, testing product concepts, and 3D modeling Prototypes are made by inventors that precisely replicate in a three-dimensional setting the volume, pressure, friction, load, etc of product objects Inventor's integrated simulation and analysis tools enable users to create molds of varying complexity, including machine detail design and product visualization In order to increase CAD productivity, reduce errors, and save time, Inventor now combines design communication capabilities with CAD
Figure 6.1 Autodesk inventor professional 2022 software
6.1.2 Design the model frame on Inventor Professional
- The implementation team used 3D Inventor Professional simulation software to create and calculate data to achieve the best accuracy when assembling the pieces in order to avoid errors during the creation of the model frame Both durability and beauty are guaranteed by the model's details on the frame
- After receiving the model, the control panel takes up a large area, hindering installation and repair of the engine side So remember to measure and draw the most suitable design
Figure 6.2 3D design model framework in Inventor Professional
Figure 6.3 2D design of the model frame
- Based on the technical specifications of the drawing board, the advance team prepared paraphernalia, necessary equipment and protective gear: Cutting machine, heat exchanger, iron rod, 3mm thick rectangular iron box
- When cutting the model, first operate the control devices of the air conditioning system and the meter Measure and mark the cutting point on the model, cut the model according to the draw
Figure 6.4 Disassemble and install the control parts to be cut
Figure 6.5 Make a mark on the design cutout
Figure 6.6 Original image of the unbuilt model
Figure 6.7 Model after cutting and welding according to draw board
Design the control panel on the model
6.2.1 Design control panel on autocad
Based on the redesigned model, the team measured the control panel frame and measured control parts such as dashboard, 3 air vents, key, emergency switch, air condiontiong control panel and OBD II Then proceed to design the control panel using mica panels according to the data
Figure 6.8 Control panel of the model using autocad
6.2.2 Restore and check electrical circuits on the control panel
This model has been abandoned for several years, so the wires have rotted and broken due to model movement and rat damage When rebuilding the model, the control panel must be redone for aesthetics and to ensure the most accurate measurement of the signal pins
- After having a detailed drawing board, the team had the advertising department cut and engrave an 8mm thick mica sheet just like the drawing board
- Receive the control panel, bring it back and install it on the model and the sets are assembled Reconnect the engine and air conditioning test lines
Figure 6.9 Initial control panel when receiving the topic
Figure 6.10 Control panel after design
Figure 6.11 Angles taken of the model after completion
Rebuild the electronic fuel injection mechanical model with Toyota's automatic air
6.3.1 About the 2NZ-FE Toyota engine
6.3.1.1 Procedure proposed when diagnosing the engine
- Survey and learn about the 2NZ-FE Toyota engine control system in theory (In-chapter 4)
- Clean the model by spraying compressed air and wiping to remove dust and dirt, observing small details of each part
- Check the engine's electrical system and the original wiring of the model
Figure 6.14 The electrical system controls the engine on the model
+ Step 1: Search the circuit diagram of 2NZ-FE Toyota Yaris 2009 engine, fuse box
+ Step 2: List the engine control systems, check the electrical wires on the circuit diagram of each part (This section looks at the engine diagnostics section in chapter 3)
+ Step 3: Conduct testing of each control part against the technical specifications given by the manufacturer
- Divide into each control system, check and clean the details in the system to operate smoothly
- After cleaning, install according to the manufacturer's instructions and do a final general check
- Start the engine and observe the engine's operating condition after maintenance Attach the G-scan3 diagnostic machine to find errors and view data analysis parameters on the diagnostic machine
Figure 6.15 Use the G-scan 3 diagnostic machine
Figure 6.16 Datasheet of 2NZ-FE engine system after maintenance
- When there is an error, fix it based on the disease and find a way to fix it based on Toyota training documents or ask the instructors to improve the engine
- After the system is stable, you should re-lay the wires to avoid ground shorts, insulate the wires and make them neater and easier to see
6.3.1.2 Procedures for checking engine control systems
- Step 1: Measure the connectors of each injector and the fuel pump connector (see diagnostics 3.5)
- Step 2: Disassemble the fuel system from the model, clean it thoroughly to clearly observe the small details of each part and then check their operation
- Step 2: Observe the fuel pipes from the fuel tank to the engine, check for cracks and then replace them
- Step 3: Check the fuel pump assembly After cleaning, check and test the fuel pump has turned off because the gasoline in the tank has not been cleaned for a long time, causing the pump to clog and need to be replaced
- Step 4: Next, the oscillator and injector are cleaned with a bottle of injector cleaning solution (3T carb & choke cleaner) Replace all injector seals (23291-Injector Vibration, 23250B-O Ring injector)
- Step5: Install the injector seals attached to the oscillating stamper, check the wiring to check how the oscillating injectors work, and clean the injectors inside
- Step 6: After carefully checking each part, the injector system is stable, install it on the model and read the Toyota training book to install each part
Figure 6.17 How to wire to test injectors
- Ways to test and clean inside the injector:
+ Pin 1 is activated with (+) 5-7V power, to get 5-7V power, you need to have a 12V battery connected through the transformer circuit (The injector receives ECU signals, so do not use a power source above 12V, so when testing, the power source must be low to avoid damaging the injector)
+ Pin 2 connects to ground battery
+ Connected to the injector, a bottle of injector cleaning solution is connected to the pipe When we transfer the solution to the needle, we apply 7V to the needle to clean it and observe the needle's injection volume
Figure 6.19 Clean the fuel pump assembly and fuel tank
Figure 6.20 Replace fuel pump with new denso
Figure 6.21 Replace all injector seals
Figure 6.22 After testing and cleaning the injectors and dampers
- Step 1: Measure the connectors of each ignition coil (see diagnostics section 3.5)
- Step 2: Disassemble and install the burners on the engine cover, remember to mark each burner and spark plug correctly for each machine and observe cleanliness
- Step 3: Check if the spark plug is still working or not, by testing the ignition plug and installing the wire diagram according to the picture
- Step 4: After carefully checking each part, the ignition system is stable, install it on the model and read the Toyota training book to install each part like in the factory
Figure 6.23 Clean the ignition coil and spark plugs
Figure 6.24 How to wire to test ignition coil
- How to wire to test integrated ignition coil
+ Pin 1 (B+) connects to battery +, Pin 4 (E) connects to battery –
+ Pin 3 (IGT) is connected in series with a 1KΩ resistor, then excited with a positive battery And fish the exposed ground wire with a distance of 1cm from the spring end of the igntion coil
- Hence, when the IGT wire is connected to the positive resistor, a spark will be created
Be absolutely careful not to keep the mass too far from the ignition coil's spring as it will create a large spark and cause an electric shock
- Step 1: Unplug the coolant sensor and the sensor on the engine body, measure the voltage and check the resistance of the sensor (see diagnostics 3.4)
- Step 2: Drain the cooling water, disassemble the cooling water system such as the water tank, water pipes, water pump Observe each set and if seriously damaged, consider replacing
- Step3: After observing, clean each limb to make sure the water tank uses high water pressure to remove long-lasting water residues and check the tank for leaks
- Step 4: Once cleaned, we install the system into the model as originally designed
- Step 5: Add engine coolant, exactly 5L of water and check for tightened necks and water leaks
Figure 6.26 Water pump and thermostatic valve assembly
Figure 6.27 Water tank and water pipes after cleaning
- Step 1: Remove the connector and sensors on the intake manifold such as Mass Air Flow, Electronic Butterfly Outlet, EGR and VSV, measure the voltage and check the resistance of the sensors (see diagnostics 3.4 section)
- Step 2: Disassemble the intake manifold and clean it While disassembling, remember to use a clean towel to cover the intake manifold on the engine body to prevent dust from flying in Observe each set and if severely damaged, consider replacing
- Step 3: After observing, clean each limb with throat cleaning solution
- Step 4: Once cleaned, we install the system into the model as originally designed
- Step 5: After installation, check the general overview of the intake system, focusing on tightness to prevent air from escaping outside and the air must be clean
Figure 6.29 The intake system components clean
- Step 1: The group checks the oil, and removes the oil probe to see the amount of oil and oil condition Although the oil is still usable, the engine has now been unused for nearly 5 years, by which time the oil has also degraded, so the team decided to buy Toyota 10w-
30 oil and an internal oil filter that matches the engine on the model
- Step 2: When the spare parts arrived, the group removed the oil filter, drained the oil, removed the oil crankcase cover, and cleaned the oil filter and oil pump When draining the oil, check to see if the oil has deposits or metal fragments of engine parts in the oil
- Step 3: After cleaning the details of the oil system, install the parts and replace the new oil filter, then add oil
Figure 6.30 Genuine engine oil and oil filter
Figure 6.31 Replace new engine oil
Once the engine is operating stably, the team next diagnoses and checks the 2002 Camry's air conditioning system
- Check if the signal from the A/C control unit is working or not? And when the A/C is turned on, the compressor operates but does not cool and the condenser fan speed cannot be adjusted So our group received the air conditioning system problem and went to check it
- Turn on the A/C and close the clutch, it means that the electrical system from the control box to the compressor is stable, but the system is not cold because there is a refrigerant leak or out of refrigerant, maybe one or more parts are leaking refrigerant and over time all the refrigerant system, leading to the air conditioner not being cold Let's check the system for leaks:
+ Step 1: Vacuum the compressor (see the air conditioning gas charging section), then observe the pressure gauge to see if the system is tight or not? If the system is closed, add air conditioning gas to the system and check how it operates On the contrary, for open systems, proceed to step 2
+ Step 2: Use an air compressor to compress air into the system to check each part that the solvent passes through (see section 2.3)
+ Step 3: After using the air compressor, the leak was found in the high pressure line in the evaporator
- The carefully check the closed system, the team brought through the refrigerant parts such as high and low pressure pipes, condenser, dryer (replaced), evaporator Test the tightness with compressed air and dip it in a tank of water
- The high pressure line in the evaporator was punctured and the aluminum was welded together quite firmly
- The high and low pressure lines in some sections showed signs of wear and were not sturdy, the team decided to replace new pipes, for example:
+ All high-pressure pipes from the compressor to the evaporator and from the condenser, from the condenser to the gas filter (Figure 6.34), from the dryer to the condenser (Figure 6.35) have been replaced with good heat-control hydraulic pipes At the high line when the system operates, the temperature is very high
PRACTICAL EXERCISES APPLICATION ON THE MODEL
Practical about EFI engine on the model
7.1.1 Check the resistance of the sensor
+ Turn the engine switch to the OFF position or completely remove the negative battery terminal
+ Use Multimeter with an OHM scale
+ Measure resistance values of sensors and coils in the inactive state
+ If the measured value does not comply with the given standard, it must be repaired or replaced
- Implementation process: using a multimeter with OHM scale, measure the resistance values of the sensors, then compare with the manufacturer's standard values
Standard value of the Resistor (Ω)
Value of the Resistor (Ω) Conclusion
Intake air Temp 20 o C 1-1.5 KΩ Intake air Temp 80 0 C 70-100 Ω
Water Temp at 20 o C 2-3 KΩ Water Temp at 80 o C 100-200 Ω
Table 7.1 Table of Standard Resistance Values of Engine Sensors
7.1.2 Check the voltage of details in engine
+ Multimeter , Engine is in good working condition
+ Set Multimeter in DC-VOLT scale
+ Battery voltage must be above 12V
+ Do not get the battery terminals wrong
+ When an abnormal phenomenon occurs, the power source must be disconnected promptly
+ Use a multimeter with the correct scale
+ Helps determine the voltage values of the sensors From there, there is a basis for finding errors in the engine electrical system
+ Connect a multimeter in parallel with the circuit
+ Compare the measured voltage value with the standard voltage
Engine Start or No Load Square pulse
G2+ – NE- No Load Sinusoidal pulse
NE+ – NE+ No Load Sinusoidal pulse
Throttle from close completely to open fully
Throttle from close completely to open fully
Table 7.2 Table of standard voltage values of engine sensors
Practical about automotive air conditioning on the model
7.2.1 Practice refill the air conditioning system using R314a refrigerant
- 220V residential power source and 12V battery
- Set of media pressure gauges
- Protective gear: Mask, gloves, chemical resistant glasses
Figure 7.1 R134 refrigerant for air conditioning systems
- After each gas release to repair or replace parts of the refrigeration system, vacuum must be performed before adding new refrigerant into the system
- A vacuum pump's function is to extract air and moisture from the air conditioning system The liquid's moisture is not truly "sucked" by the vacuum pump; rather, it boils and becomes vapor, which can be safely expelled from the system through the discharge pipe of the vacuum pump Recharging the automobile will result in the old and new gas combining, shortening the life of the entire air conditioning system, if the old gas is not completely removed
- Remove all vacuum, when applying gas R134a makes our air conditioning system cooler and just checks the tightness of the air conditioning system
+ Step 1: Install the 2 high and low pressure pipes of the pressure gauge into the charging port high low line and the remaining pipe connects to the vacuum machine as shown:
Figure 7.4 Simulate connecting the vaccuum machine and gauges to the model
+ Step 2: Open the high and low pressure gauges with 2 pressure lines, then turn on the vacuum machine
Figure 7.6 Simulate the vacuum process
+ Step 3: Suction for 10 minutes, then observe the 2 faces of the meter, the low vacuum pressure side reaches 750mmHg and then tighten the 2 valves of the meter, turn off the pump and monitor for 7-10 minutes
+ Step 4: Diagnose the system for leaks or not, and then remove the vacuum hose
Figure 7.7 Gauge value after vacuuming
7.2.1.2.2 Load refrigerant into the air conditioning system
- Step 1: After removing the intermediate pipe of the vacuum cleaner, install it in the gas tank, open the gas tank (the 2 tightly closed valves of the 2 low and high line meters) and release air from the intermediate pipe, discharge to When you feel the gas escaping, stop
Figure 7.8 Press the air release valve in the common pipe to release the air in the pipe
- Step 2: Load the refrigerant on the high pressure line (absolutely do not start the engine)
+ We open the high pressure valve slowly to the fullest, letting the gas be pumped in and at that time we place the gas tank on its back (absolutely do not open the low valve)
+ If we observe that the high pressure gauge needle does not move, we should tighten the high pressure valve
Figure 7.9 Simulate the gas charging process from the high pressure side
- Step 3: Load the low pressure line with refrigerant (start the engine)
+ Start the engine, turn on A/C Auto, set the fan level to High and the temperature to Max Cool mode
Figure 7.10.Turn on the modes when charging
+ When the high-pressure valve is tightly closed, slowly open the low-pressure valve (put the gas tank upright) and observe both sides of the meter
+ Accelerate to 1500 rpm, we observe the two clock faces again when the low pressure side reaches 1.5-2.5 kgf/cm2 and the high pressure side reaches 14-16 kgf/cm2
+ During the process of filling gas, we pay attention to observe the gas eye on the filter tank until we no longer see tiny amounts of gas, then we can stop filling gas
Figure 7.11 Value when loading refrigerant into the system
- Close the low pressure valve and close the gas tank valve
- Let the engine run for about 10 minutes, then turn off the engine and remove the intake meter wire (remember to close the 2 pipes right at the intake and exhaust valves)
7.2.2 Practice check for refrigerant leaks in the system:
- During the vacuum process, the gas is not sealed or the gas runs out after being used for a few days There are many ways to find leaks in each part and each part has a different way to find it:
+ B1: Pump compressed air into any pressure line
+ Step 2: Prepare soap, apply it to the pipe and where the parts connect to the pressure line and observe When you see large bubbles of gas bubbling up, it means there is a leak
+ Step 3: Disassemble and repair, weld or replace
- When replacing pipes, when reassembling, remember to replace the seals and tighten the screws tightly
- Check the evaporator and condenser: there are 2 ways: in and out Seal 1 of the 2 lines, add air to the remaining line and soak in water Observe, if there is a powder phenomenon, the frame is punctured or do not continue to check other parts
- Check the dryer: usually the gas filter should be changed periodically about 3-4 years
- After checking for leaks, we begin reinstalling the system before vacuuming and recharging the gas
7.2.3 Practice observation and listening around the system
Figure 7.12 Observation and listening method
- Observe and listen to all parts of the air conditioning system working to detect problems:
+ Observe the belt connecting the compressor clutch to the moving parts of the engine: A loose drive belt will cause noise, slippage and wear, leading to the compressor not working efficiently
+ Observe detailed parts of the system such as air filter, condenser, condenser :
• If the air filter is used for a period of time, it has a lot of dust and dirt, which will reduce the system's ability to work and create an unpleasant odor when the air conditioner is turned on Therefore, this part must be cleaned or replaced periodically
• The condenser installed next to radiator is a part that collects dust, and oil can appear on the heatsink fins, reducing the heat exchange ability of the refrigerant
• The evaporator as well as the condensor will have less dust, but there is a risk of frozen pipes, refrigeration oil spills
+ Observe the pipe connection points: when there are oil stains or bubbles appear, it proves that the system is leaking It is necessary to replace the pipe seal and tighten the bolts at the joints to prevent refrigerant leakage
+ Check the amount of refrigerant in the system: by observing the status when the engine starts, turns on A/C, turns on Full fan speed, Max cool and through the observation sight glass to know the amount of refrigerant in the system
• If you see a large amount of air bubbles appearing at the sight glass, the system is lacking refrigerant, making the system not cool In this situation, there is not enough refrigerant loaded or the system has a refrigerant leak
• If there are no air bubbles in the sight glass, the system is overloaded with too much refrigerant or the condenser is clogged
• If a small amount of foam appears at the glass, the system is stable and the system is filled with enough refrigerant
Figure 7.13 Sight glass on the air conditioning system