Powertrain Management: Description and Operation
Engine ControlSystem 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 is explained here.
1. Input Signals
1. Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built-in thermistor with a resistance which varies according to the water temp. is input into TERMINAL THW of the hybrid vehicle control ECU as a control signal.
2. Intake air temp. signal circuit
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 into TERMINAL THA of the hybrid vehicle control ECU.
3. 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).
4. RPM signal circuit
Camshaft position and crankshaft position are detected by the VVT sensor RH and crankshaft position sensor. The camshaft position is input as a control signal to TERMINAL VV1+ of the hybrid vehicle control ECU, and the engine RPM is input into TERMINAL NE+.
5. 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.
6. Vehicle speed signal circuit
The vehicle speed sensor, detects the vehicle speed and input to the speed sensor of the skid control ECU, from skid control ECU to TERMINAL SPD of the hybrid vehicle control ECU, Via combination meter.
7. Shift lever position sensor signal circuit
The shift lever position sensor detects whether the shift position is in neutral, parking or not, and inputs a control signal into TERMINALS N, P of the hybrid vehicle control ECU.
8. Battery signal circuit
Voltage is always supplies to TERMINAL BATT of the hybrid vehicle control ECU.If you turn on the ignition SW, the current goes from TERMINAL MREL of the hybrid vehicle control ECU to the IGCT relay and put on the relay, and the voltage related to the hybrid vehicle control ECU operation is supplied to TERMINALS +B1, +B2 of the hybrid vehicle control ECU through the IGCT NO.2 fuse.
9. Intake air volume signal circuit
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.
10. Engine knock signal circuit
Engine knocking is detected by the knock sensor (Bank 1) and (Bank 2), then the signals are input into TERMINALS KNK1 and KNK2 of the hybrid vehicle control ECU as a control signal.
11. 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.
2. Control System
- SFI system
The SFI system monitors the engine condition through the signals, which are input from each sensor to hybrid vehicle control ECU. The best fuel injection volume is decided based on this data and the program memorized by the hybrid vehicle control ECU, and the control signal is output to TERMINALS #10, #20, #30, #40, #50 and #60 of the hybrid vehicle control ECU to operate the injector (Inject the fuel). The SFI system produces control of fuel injection operation by 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 input to the hybrid vehicle control ECU from each sensor. The best ignition timing is decided according to this data and the memorized data in the hybrid vehicle control ECU, 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.
- Heated oxygen sensor heater control system
The heated oxygen sensor heater control system turns the heater on when the intake air volume is low (Temp. of exhaust emissions is low), and warms up the heated oxygen sensor to improve detection performance of the sensor. The hybrid vehicle control ECU evaluates the signals from each sensor, current is output to TERMINALS HT1B and HT2B, controlling 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 (Temp. of exhaust emission 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, current is output to TERMINALS HA1A and HA2A, controlling the heater.
3. 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.
4. 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.