3.0 Components of the ignition system
1 - Electronic control unit
2 - Engine speed sensor
3 - Throttle valve angle potentiometer
4 - Coolant temperature sensor
5 - Intake air temperature sensor
6 - Lambda probe
7 - Knock sensor
8 - Speed sensor
9 - Relay step (double) injection
Some of them are also parts of the fuel injection system. Depending on the type of engine, some changes in the configuration of the system are possible.
Electronic control unit
The electronic control unit is equipped with a multi-pin plug connector, which allows you to provide power to the parts of the fuel injection and ignition systems, as well as receive information from the elements of these systems.
Engine speed sensor
The engine speed sensor consists of a coil with a winding and a magnetic core. From this sensor, the electronic control unit receives information about the engine speed and the position of the crankshaft at the current moment. Sensor «is following» behind the revolutions of the flywheel, the ring gear of which has 60 teeth. Two teeth on the crown are missing and this is recorded by the sensor. The moment of registration corresponds to the TDC of the engine.
Throttle valve angle potentiometer
The Bosch throttle valve angle potentiometer informs the electronic control unit of the position of the throttle valve, which can close the intake port, open it partially or completely. Based on the information received, the electronic control unit determines the mode of acceleration and increase in speed, braking or forced idling. The electronic control unit provides power to the potentiometer with a power of 5 V. Depending on the position of the throttle valve, the potentiometer sends signals with a current strength of 0 to 5 V to the unit.
Coolant temperature sensor
The coolant temperature sensor is located in the outlet pipe and informs the control unit about the temperature of the liquid (engine) at this moment. The signal about the temperature of the coolant is sent to the control unit as an electrical resistance, the strength of which depends on the temperature.
Intake air temperature sensor
The intake air temperature sensor is mounted on the throttle body and reports the temperature of the intake air to the combustion chambers to the control unit. Like the coolant temperature sensor, this sensor also sends its signals in the form of current of different strengths.
Ignition advance sensor (TDC cylinder #1). Figure 3.0 does not show this sensor. Such a sensor is installed on the cylinder head of a 16-valve engine. It recognizes the position of the piston of cylinder No. 1 and, based on its information, the ignition timing is adjusted.
Lambda probe
The lambda probe is located in the exhaust pipe of the mufflers in front of the catalyst. It is designed to inform the electronic control unit about the oxygen content in the OT. The lambda probe is heated, which ensures that it reaches operating temperature quickly.
Knock sensor
The knock sensor is screwed into the cylinder block under the intake manifold. Its information allows the control unit to correct the moment of ignition of the air-fuel mixture in the chamber of the corresponding cylinder.
Vehicle speed sensor
The vehicle speed sensor informs the control unit about the current speed.
Step relay (double) injection
step relay (double) injection is mounted on the holder of the control unit and connected to the following parts:
- A) fuel pump;
- b) throttle angle potentiometer;
- V) idle speed control;
- G) fuel injectors;
- d) control unit;
- and) ignition coil;
- h) heating element of the lambda probe;
- e) adsorber solenoid valve;
- To) valve for reconfiguring the cavity of the intake manifold pipes on a 16-valve engine.