Powertrain Management: Description and Operation

SYSTEM OUTLINE

The engine control system utilizes a microcomputer and maintains overall control of the engine, transmission etc. An outline of the engine control is given here.

1. INPUT SIGNALS

1. Engine coolant temperature signal circuit
The engine coolant temperature sensor detects the engine coolant temperature and has a built-in thermistor with a resistance, which varies according to the engine coolant temperature The engine coolant temperature which is input into TERMINAL THW of the engine control module as a control signal.

2. Intake air temperature signal circuit
The intake air temperature sensor is installed in the mass air flow meter and detects the intake air temperature which is input as a control signal to TERMINAL THA of the engine control module.

3. Vehicle speed signal circuit
The vehicle speed signal is input from the ABS speed sensor to skid control ECU, and are sent to the engine control module through communication control.

4. RPM signal circuit
Camshaft position is detected by the VVT sensors and its signal is input to TERMINALS W1+ and VV2+ of the engine control module as a control signal. Also, engine RPM is detected by the crankshaft position sensor and is input as a control signal to TERMINAL NE+.

5. Throttle position signal circuit
The throttle position sensor detects the throttle valve opening angle as a control signal, which is input into TERMINAL VTA1 of the engine control module.

6. Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. With the ignition SW turned on, the voltage for engine control module start-up power supply is applied to TERMINAL +B of the engine control module via the EFI relay.
The current flowing through the IGN fuse flows to TERMINAL IGSW of the engine control module.

7. Intake air volume signal circuit
Intake air volume is detected by the mass air flow meter and the signal is input to TERMINAL VG of the engine control module as a control signal.

8. Stop light SW signal circuit
The stop light SW is used to detect whether the vehicle is braking or not and the signal is input into TERMINAL STP of the engine control module as a control signal.

9. Starter signal circuit
To confirm whether the engine is cranking, the voltage is applied to the starter motor during cranking is detected and the signal is input into TERMINAL STA of the engine control module as a control signal.

10. Engine knock signal circuit
Engine knocking is detected by knock sensors and the signal is input into TERMINALS KNKL and KNKR as a control signal.

11. Air fuel ration signal circuit
The air fuel ration is detected and input as a control signal into TERMINALS AFL+ and AFR+ of the engine control module.

12. Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINAL OXS of the engine control module.
To maintain stable detection performance by the heated oxygen sensor, a heater is used for warning the sensor. The heater is also controlled by the engine control module (HTS).

13. Fuel cut in a collision
The system receives the collision signal from airbag sensor assembly in the vehicle has a collision and stops the fuel pump operation on the side of the engine control module.

2. CONTROL SYSTEM

- SFI system
The SFI system monitors the engine condition through the signals input from each sensor (Input signals from (1) to (12) etc.) to the engine control module. And the control signal is output to TERMINALS #10, #20, #30, #40, #50 and #60 of the engine control module to operate the injector (Inject the fuel). The SFI system controls the fuel injection operation by the engine control module in response to the driving conditions.

- ESA system
The ESA system monitors the engine condition through the signals input to the engine control module from each sensor (Input signals from (1) to (12) etc.). The best ignition timing is decided according to this data and the memorized data in the engine control module and the control signal is output to TERMINALS IGT1 IGT2, IGT3, IGT4, IGT5 and IGT6. This signal controls the igniter to provide the best ignition timing for the driving conditions.

- ACIS
The ABS includes a valve in the bulkhead separating the surge tank into two parts. This valve is opened or closed according to the driving conditions to control the intake manifold length in three stages, for increased engine output in all ranges from low to high speeds, when idling.

3. DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunction in the engine control module signal system, the malfunctioning system is recorded in the memory. The malfunctioning system can be found by reading the code displayed by the check engine warning light.

4. FAIL-SAFE SYSTEM
When a malfunction has occurred in any system, if there is a possibility of engine trouble being caused by continued control based on the signals from that system, the fail-safe system either controls the system by using data (Standard values) recorded in the engine control module memory or else stops the engine.