System Outline
This system utilizes a hybrid vehicle control ECU and maintains overall control of the engine, transaxle 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 water temperature. The engine coolant temperature is input into TERMINAL THW of the hybrid vehicle control ECU 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 hybrid vehicle control ECU.
- 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 hybrid vehicle control ECU. To maintain stable detection performance by the heated oxygen sensor, a heater is used for warming the sensor. The heater is also controlled by the hybrid vehicle control ECU (HT1B and HT2B).
- RPM signal circuit
The engine RPM is detected by the crankshaft position sensor and the signal is input into TERMINAL NE+ of the hybrid vehicle control ECU.
- Throttle signal circuit
The throttle position sensor detects the throttle valve opening angle as a control signal, which is input into TERMINAL VTA1 of the hybrid vehicle control ECU.
- Vehicle speed signal circuit
The vehicle speed sensor detects the vehicle speed and inputs it to the speed sensor of the skid control ECU. It is then sent from the skid control ECU, via the combination meter, to TERMINAL SPD of the hybrid vehicle control ECU.
- Shift lever position sensor signal circuit
The shift lever position sensor detects whether the shift position is in neutral, parking or something else, and inputs a control signal into TERMINALS N and P of the hybrid vehicle control ECU.
- Battery signal circuit
Voltage is always supplied to TERMINAL BATT of the hybrid vehicle control ECU.
If you turn on the ignition SW, current flows from TERMINAL MREL of the hybrid vehicle control ECU to the IGCT relay, and the voltage related to the hybrid vehicle control ECU operation is supplied to TERMINALS +B1 and +B2 of the hybrid vehicle control ECU through the IGCT NO. 2 fuse.
- Intake air volume signal circuit
The intake air volume is detected by the mass air flow meter and a signal is input into TERMINAL VG of the hybrid vehicle control ECU as a control signal.
- Engine knock signal circuit
Engine knocking is detected by the knock sensors (Bank 1) and (Bank 2), then the signals are input into TERMINALS KNK1 and KNK2 of the hybrid vehicle control ECU 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 hybrid vehicle control ECU.
- Engine coolant temp. signal circuit
- Control System
* SFI system
The SFI system monitors the engine condition through the signals which are received from various sensors by the hybrid vehicle control ECU. The best fuel injection volume is based on this data and the program stored in the hybrid vehicle control ECU, and then control signals are output from TERMINALS #10, #20, #30, #40, #50 and #60 of the hybrid vehicle control ECU to operate the injectors (Inject the fuel). The SFI system controls the fuel injection operation via the hybrid vehicle control ECU in response to the driving conditions.
* ESA system
The ESA system monitors the engine condition through the signals which are received by the hybrid vehicle control ECU from various sensors. The best ignition timing is then decided according to this data and the data stored in the hybrid vehicle control ECU, and control signals are output from TERMINALS IGT1, IGT2, IGT3, IGT4, IGT5 and IGT6. These signals control the igniters to provide the best ignition timing for the driving conditions.
* 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 sensor to improve the detection performance of the sensor.
The hybrid vehicle control ECU evaluates the signals from both sensors, and then current is output to TERMINALS HT1B and HT2B, controlling the heaters.
* 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 hybrid vehicle control ECU evaluates the signals from each sensor, and current is output to TERMINALS HA1A and HA2A, controlling the heaters.
- Diagnosis System
With the diagnosis system, when there is a malfunction in the hybrid vehicle control ECU signal system, the malfunctioning system is recorded in the memory.
- Fail-Safe System
When a malfunction occurs in any systems, 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 hybrid vehicle control ECU memory or else stops the engine.