Bơm ECD-V - P - Speed Sensor

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

9 SERVICE TECH Vol.467 03-8

This session describes the construction and operation of products (sensors) associated with the input signal of the ECD system.

This sensor is installed on the venturi (intake) and moves in unison with the main valve in order to detect the throttle position The sensor is constructed with a variable resistor to detect the throttle position and a contact point to detect the idle position Along with the speed sensor, it is one of the main sensors used for calculating the basic injection volume

This is an electromagnetic sensor for detecting the cam angle of the injection

pump There is a magnet and a coil inside the sensor, and as the pulsar rotates,

the magnetic flux that passes through the coil increases, generating an

alternating current The pulsar is constructed of 56 teeth, with 4 toothless

sections each the size of 2 teeth The pulsar rotates once for every 2 rotations

of the engine, generating a cam angle pulse at the electromagnetic sensor

From the number of these pulses and the interval between them, the engine

ECU calculates the cam angle and the engine speed

The speed sensor, along with the throttle position sensor and the accelerator

sensor, is one of the main sensors used for calculating the basic injection

volume

1 Speed Sensor

Speed Sensor Connector

Speed Sensor

Toothless Section Roller Ring

Magnet

Pulsar

Speed Sensor

0 +

O u t p u t Voltage

Sensor Output Signal

2 Throttle Position Sensor

Throttle Position Sensor

SERVICE TECH Vol.467 03-8

The sensor is constructed with a resistor and a moving contact point in order to convert the position of the main valve into a voltage value The engine ECU supplies 5V to the VC terminal Because the sensor moves in unison with the main valve, when the moving contact point moves, a voltage proportionate to the throttle position is output from the VA terminal

In some systems, the venturi (throttle valve) does not work in unison with the accelerator pedal These systems use

an accelerator sensor that is installed on the accelerator pedal and directly detects the accelerator position This sensor uses a hall element that reacts to magnetic force to generate electromotive force It is a non-contact type using

a dual system with two internal electric circuits, increasing durability and reliability Along with the speed sensor, it is one of the main sensors used for calculating the basic injection volume

The idle condition is detected by whether the contact

point is on or off The contact point closes when the main

valve is fully closed (idling), which generates continuity

between the IDL terminal and E2 When not idle, the

contact point is open The engine ECU judges whether

or not the engine is idling, and corrects the idle speed

control and the acceleration rate

3 Accelerator Sensor

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This sensor detects the air pressure inside the intake manifold and sends a voltage signal to the engine ECU It is a semi conductor pressure sensor, with internal crystals (silicone chips) that change their electrical resistance when pressure is increased The intake air pressure (absolute pressure) is converted into an electrical signal and amplified

It is sent to the engine ECU, where the intake air volume is calculated The output voltage increases during the charging boost of the turbo charger, in order to increase the injection volume

The coolant temperature sensor is installed on the engine cylinder block to detect the temperature of the engine coolant The sensor uses a thermistor, the resistance of which varies according to the temperature The temperature variation is converted into a resistance variation, which is detected As the temperature increases, the resistance of the thermistor decreases When the coolant temperature is low, the injection volume is increased and the injection timing is advanced

The intake air temperature sensor is installed inside the air cleaner to detect the temperature of the intake air The sensor uses the same type of thermistor as the coolant temperature sensor The density of the air varies with temperature, so the injection volume is corrected

The fuel temperature sensor is installed on the injection pump It detects the temperature of the fuel and sends the information to the engine ECU It uses the same type of thermistor as the coolant temperature sensor The viscosity

of the fuel varies with temperature, so the injection volume is corrected

4 Intake Air Pressure Sensor

5 Coolant Temperature Sensor and Intake Air Temperature Sensor

6 Fuel Temperature Sensor

SERVICE TECH Vol.467 03-8

A resistor molded from plastic or a ROM is installed on the side of the injection pump The engine ECU reads the data from the resistor or ROM to calculate the fuel injection volume There are 31 types of resistors with different resistance values, so the most appropriate one is used

The ROM type can store over 10 data points dealing with the engine speed and the accelerator position This enables high accuracy fuel injection control whatever the engine conditions, which lowers exhaust gas emissions The ROM can be modified when adjusting the pump, so that during normal driving a fixed value is input to the engine ECU

7 Correction Resistor and Correction ROM