Bơm ECD-V - P - Intake Restriction Control

Tất cả tài liệu về bơm ECD-V (tài liệu đào tạo của Denso ECD): -Composition and Construction of ECD-V3 Pump System -Determining the Injection Timing -ECD-V Series -ECD-V4 Outline -ntake Restriction Control -Outline of Injection Ti

"Intake Restriction Control, EGR Control and Glow Control" ECD (Electronically Controlled Diesel): An electronically controlled system for diesel fuel injection.

Eighth Session

This control system adjusts the air intake volume of the engine to secure a comfortable and safe drive

The "intake restriction valve (sub valve)" located halfway along the intake manifold opens and closes according

to the engine conditions This reduces noise and vibration, and prevents overrun

When starting the engine Fully opens the sub valve to minimize the emission of white

smoke and black smoke When idling Restricts the air intake volume to reduce noise When engine is stopped Fully closes the sub valve to reduce engine vibration and noise During Abnormally high engine speed Fully closes the sub valve to prevent overrun

The sub valve installed in parallel to the main valve can be moved to 3 positions, "Fully open, Half open, or Fully closed", with the 2 level diaphragm This is how the air intake volume is controlled

1-1 Control Outline

1-2 2 Level Diaphragm Type Intake Restriction Mechanism

Sub Valve

2 Level Diaphragm

Vacuum Pump Air

2 Level Diaphragm Chamber B

S u b Valve

M a i n Valve

Accelerator Pedal

Accelerator Position Engine Speed Key Switch Refrigerant Temperature

Vacuum

Engine ECU

VSV1 VSV2 Chamber A

Air

This component is constructed from 2 diaphragms and springs, and a rod Chamber A and chamber B are separated by the diaphragms When a vacuum or air pressure is introduced to these chambers the rod moves, which via the link makes the sub valve move to one of the 3 positions

This is a solenoid valve that selects the airflow ports according to the signal received from the engine ECU, switching the pressure feed to the diaphragm chamber

The energization of VSV1 or VSV2 is selected according to the driving and engine conditions A vacuum or air pressure is channeled into the diaphragm chamber, which moves the sub valve to one of 3 positions and adjusts the intake air volume

Active Air Flow

Energized

(ON)

Not

Energized

1-3 Component Construction and Operation

2 Level Diaphragm

Vacuum

Vacuum

Vacuum

Air Pressure

Air Pressure Air Pressure

Rod

Chamber B

Spring

Chamber A

VSV (Vacuum Switching Valve)

Air Port

E Port

F Port

Chamber A or Chamber B Diaphragm Port

To

From Vacuum Port

1-4 Intake Restriction Position and Driving Conditions

Sub Valve Position

Fully Open

Half Open

Fully Closed

Actuator VSV

VSV1

OFF OFF Air Pressure Air Pressure

Vacuum

Vacuum

Air Pressure

Vacuum

ON

ON ON

OFF

VSV2 Chamber A Chamber B

Diaphragm Chamber Driving Conditions

• When starting (starter ON)

• When idling during warm-up

• When driving

• When idling after warm-up

• When engine stalled (IG/ON)

• When abnormally high engine speed is detected

• For 2 seconds after stopping the engine

• When overrun is detected

• When SPV abnormality is detected

Engine Conditions

Part of the exhaust gas is recirculated to the intake side, which slows combustion and controls NOx emissions.

In EGR (Exhaust Gas Recirculation) control, an amount of exhaust gas appropriate to the driving conditions is returned to the intake manifold and reinserted in the combustion process This system lowers the combustion temperature and reduces nitrogen oxide (NOx) emissions

• EGR Valve

This component is constructed from a diaphragm, spring and valve When a vacuum is introduced to the diaphragm chamber, a valve that is interlinked with the diaphragm opens The exhaust gas flows from the exhaust manifold to the intake manifold side

• E-VRV (Electric Vacuum Regulating Valve)

This is a solenoid valve for switching the vacuum Duty control is performed by the engine ECU When the solenoid valve goes on or off, the vacuum from the vacuum pump is switched, which controls the vacuum feed

to the diaphragm chamber of the EGR valve

Duty Control

This control utilizes the duty ratio

The duty ratio is the ratio of energized (ON) duration to non-energized (OFF) duration It

is calculated using the following formula, in which the ON duration (t) is divided by the unit of time (T)

2-1 Control Outline

Injection Pump

Vacuum Pump (Vacuum)

Exhaust Manifold

Engine Speed Signal Accelerator Position Signal

Throttle Position Sensor

Diaphragm Chamber Air

EGR Valve

Coolant Temperature Sensor

Engine ECU

Component Construction and Operation

Filter

EGR Valve Vacuum Pump Coil

Duty Ratio = Tt × 100 (%)

ON

t T OFF

This control improves startability during cold weather and reduces emission gases and noise.

The heat generating part is a "ceramic glow plug" that uses a conductive ceramic heating element

The resistance at ordinary temperatures is about 0.5 , and when current flows it rapidly generates heat However as the temperature increases the resistance of the control coil also increases, and the electric volume gradually decreases This "self control function" maintains a roughly constant temperature

A heat source installed in the engine combustion chamber improves startability by both warming the air inside the combustion chamber and

by acting as an ignition source for the fuel

In addition, even after the engine is started, it generates heat for a limited time to reduce the emission of white smoke and diesel knock noise

3-1 Control Outline

Glow Plug

Auxiliary

Combustion

Chamber

Glow Relay

Glow Plug

Glow Plug Indicator Lamp

C o o l a n t Temperature Sensor

Engine ECU

3-2 Glow Plug

Type With Control Coil

Energization Time (Sec.)

Self Control Function Temperature(°C)

12 1000

Ceramic Glow Plug

Ceramic Heating Element

(Resistance at Ordinary Temperatures : About 0.5 )