System Outline
This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline of the engine control system is explained here.
- Input Signals
- Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temperature and has a built-in thermistor whose resistance varies according to the engine coolant temperature is input into TERMINAL THW of the engine control module as a control signal.
- Intake air temp. signal circuit
The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temperature, which is input as a control signal into TERMINAL THA of the engine control module.
- Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINALS OX1B and OX2B of the engine control module.
- RPM signal circuit
The camshaft position is detected by the VVT sensors (Bank 1 intake side, bank 2 intake side, bank 1 exhaust side, bank 2 exhaust side) and the signals are input to TERMINALS EV1+, EV2+, VV1+ and VV2+ of the engine control module as control signals. Also, the engine RPM is detected by the crankshaft position sensor which is installed in the cylinder block and the signal is input into TERMINAL NE+ of the engine control module as a control signal.
- Throttle position sensor signal circuit
The throttle position sensor detects the throttle valve opening angle as a control signal, which is input into TERMINALS VTA1 and VTA2 of the engine control module.
- Vehicle speed circuit
The vehicle speed sensor detects the vehicle speed, and the signal is input into TERMINAL SPD of the engine control module via the combination meter, from TERMINAL SP1 of the skid control ECU with actuator.
- Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the power SW is pushed on (Power SW type), or when the ignition SW is turned on (Ignition SW type), the voltage for engine control module start-up power supply is applied to TERMINAL +B and +B2 of engine control module via EFI relay.
- Intake air volume signal circuit
The 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.
- Stop lamp SW signal circuit
The stop lamp 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.
- Starter signal circuit
To confirm whether the engine is cranking, the voltage which is being 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.
- Engine knock signal circuit
Engine knocking is detected by knock sensors No. 1 and No. 2, then the signals are input into TERMINALS KNK1 and KNK2 of the engine control module as control signals.
- Air fuel ratio signal circuit
The air fuel ratio is detected and input as a control signal into TERMINALS A1A+, A2A+ of the engine control module.
- Engine coolant temp. signal circuit
- Control System
* SFI system
The SFI system monitors the engine conditions through the signals received from the various sensors by the engine control module. Then control signals are output from the engine control module TERMINALS #10, #20, #30, #40, #50 and #60 to operate the injectors (Fuel injection). The SFI system controls the fuel injection via the engine control module in response to the driving conditions.
* ESA system
The ESA system monitors the engine conditions through the signals received from the various sensors by the engine control module. The best ignition timing is determined according to this data and the data stored in the engine control module. Then control signals are output from TERMINALS IGT1, IGT2, IGT3, IGT4, IGT5 and IGT6, and these signals control the igniters to provide the best ignition timing.
* Heated oxygen sensor heater control system
The heated oxygen sensor heater control system turns the heater on when the intake air volume is low (Exhaust emissions temperature is low), and warms up the heated oxygen sensors to improve their detection performance. The engine control module evaluates the signals from the sensors, and outputs current from TERMINALS HT1B or HT2B to control the heater. Air fuel ratio sensor heater control system
* The air fuel ratio sensor heater control system turns the heater on when the intake air volume is low (Exhaust emissions temperature is low), and warms up the air fuel ratio sensor to improve detection performance of the sensor.
The engine control module evaluates the signals from the sensor, and current is output from TERMINALS HA1A and HA2A, controlling the heater.
* ACIS
The ACIS includes a valve in the bulkhead separating the surge tank into two parts. This valve is opened and closed in accordance with the driving conditions to control the intake manifold length in two stages, to increase the engine output in all ranges from low to high speeds.
* ETCS-i
The ETCS-i optimizes the engine output in accordance with the accelerator pedal opening, under all driving conditions.
* VVT-i
Optimizes the camshaft valve timing in accordance with the engine conditions.
- 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 on the malfunction indicator lamp.
- Fail-Safe System
When a malfunction has occurred in any system, there may be a possibility of causing engine trouble due to continued control based on that system. If that is the case, the fail-safe system either controls the system using the data (Standard values) recorded in the engine control module memory, or else stops the engine.