Powertrain Management: Description and Operation

System Outline

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

1. Input Signals

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

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

3. Power steering oil pressure signal system
Power steering oil pressure is detected by the power steering oil pressure SW and is input as a control signal to TERMINAL PSW of the engine control module.

4. RPM signal system
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor. Camshaft position is input as a control signal to TERMINAL G22+ (2ZZ-GE) or G2+ (1ZZ-FE) of the engine control module, and engine RPM is input into TERMINAL NE+.

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

6. Vehicle speed signal system
The vehicle speed is detected by the ABS speed sensor and the signal is input to TERMINAL SPD of the engine control module via the comb. meter and the skid control ECU with actuator. (w/ ABS)

The vehicle speed is detected by the vehicle speed sensor installed in the transaxle and the signal is input to TERMINAL SPD of the engine control module via the comb. meter. (w/o ABS)

7. NSW signal system (A/T)
The Park/Neutral position SW detects whether the shift position is in neutral or not, and inputs a control signal to TERMINAL NSW of the engine control module.

8. A/C SW signal system
The operating voltage of the A/C SW is detected and is input as a control signal to TERMINAL A/CS of the engine control module.

9. Battery signal system
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned to on, voltage for engine control module operation is applied via the EFI relay to TERMINAL +B of the engine control module.

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

11. STA signal system
To confirm that the engine is cranking, the voltage applied to the starter motor during cranking is detected and is input as a control signal to TERMINAL STA of the engine control module.

12. Oxygen sensor signal system
The oxygen density in the exhaust gases is detected and is input as a control signal into TERMINALS OX1A and OX1B of the engine control module. To maintain stable detection performance by the oxygen sensor, a heater is used for warming the sensor. The heater is also controlled by the engine control module (HT1A and HT1B).

13. Engine knock signal system
Engine knocking is detected by the knock sensor and input as a control signal to TERMINAL KNK1 of the engine control module.

14. Electrical load signal system
When systems which cause a high electrical load such as the rear window defogger, taillight are turned on, a signal is input to TERMINALS ELS and ELS2 as a control signal.

15. Vapor pressure signal system
Vapor pressure is detected by the vapor pressure sensor and is input as a control signal to TERMINAL PTNK of the engine control module.

2. Control System

- SFI system
The SFI system monitors the engine conditions through the signals, which are input from each sensor to the engine control module. Based on this data and the program memorized in the engine control module, the most appropriate fuel injection timing is decided and current is output to TERMINALS #10, #20, #30 and #40 of the engine control module, operating the injectors (to inject fuel). This is the system which finely controls the fuel injection in response to the driving conditions, through the engine control module.

- ESA system
The ESA system monitors the engine conditions using the signals, which are input to the engine control module from each sensor. Based on this data and the program memorized in the engine control module, the most appropriate ignition timing is decided and current is output to TERMINALS IGT1, IGT2, IGT3 and IGT4 of the engine control module. This output controls the ignition coil and igniter No. 1, No. 2 , No. 3 and No. 4 to produce the most appropriate ignition timing for the driving conditions.

- IAC system
The IAC system increases the RPM and provides idle stability for fast idle-up when the engine is cold, and when the idle speed has dropped due to electrical load and so on. The engine control module evaluates the signals from each sensor, and outputs current to TERMINAL RSD to control the idle air control valve.

- knock control system
knock control system controls the gate based on the engine rotation speed and detects knocking by the peak value of the knock sensor output during the gate open period, and then controls it to the most suitable ignition timing in proportion to the driving condition.

- Evapoparge control system
This system leads the vapor stuck to the canister to the serge tank in order not to agitate the air fuel by adjusting the fuel injection volume.

The signal at this time will be output from TERMINAL EVP of the engine control module to VSV (EVAP).

3. Diagnosis System
With the diagnosis system, when there is a malfunctioning in the engine control module signal system, the malfunction system is recorded in the memory. The malfunctioning system can be found by reading the display (Code) of the malfunction indicator lamp.

4. Fail-Safe System
When a malfunction occurs 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 the data (Standard values) recorded in the engine control module memory or else stops the engine.