System Outline
This system utilizes an Engine Control Module (ECM) and maintains overall control of the Engine, transmission and so on. An outline of the Engine control is explained here.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 ECM as a control signal.
2. Intake Air Temp. Signal Circuit
The Intake Air Temp. Sensor is installed in the mass air flow and detects the intake air temp., which is input as a control signal to TERMINAL THA of ECM.
3. Oxygen Sensor Signal System
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINALS OXL, OXR and OXS of the ECM. To maintain stable detection performance by the Oxygen Sensor, a heater is used for warming the sensor. The heater is also controlled by the ECM (HTL, HTR and HTS).
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+ of ECM, and 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 VTA of the ECM. When the Valve is fully closed, the control signal is input into TERMINAL IDL.
6. Vehicle Speed Signal System
The Vehicle Speed Sensor, installed in the transmission, detects the vehicle speed and inputs a control signal into TERMINAL SP1 of the ECM.
7. Park/Neutral Position SW Signal System
The Park/Neutral Position (PNP) SW detects whether the shift position is in a neutral position (P or N) or not, and inputs a control signal into TERMINAL STA of the ECM.
8. A/C SW Signal System
The A/C amplifier inputs the A/C operations into TERMINAL A/C of ECM as a control signal.
9. Battery Signal Circuit
Voltage is constantly applied to TERMINAL BATT of the ECM. When the Ignition SW is turned ON, voltage for ECM start-up power supply is applied to TERMINAL +B of ECM via the EFI Main relay.
10. Intake Air Volume Signal Circuit
Intake air volume is detected by the Mass Air Flow Sensor and the signal is input to TERMINAL VG of the ECM as a control signal.
11. NSW Signal Circuit
To confirm whether the Engine is cranking, the voltage applied to the Starter Motor during cranking is detected and the signal is input into TERMINAL NSW of the ECM as a control signal.
12. Engine Knock Signal Circuit
Engine knocking is detected by Knock Sensor 1 and 2 and the signal are input into TERMINALS KNKR and KNKL as a control signal.
CONTROL SYSTEM
SFI (Sequential Multiport Fuel Injection) System
The SFI system monitors the Engine condition through the signals which are input from each Sensor (input signals from (1) to (12) etc.). The best fuel injection Volume is decided based on this data and the program memorized by the ECM, and the control signal is output to TERMINAL #10, #20, #30, #40, #50 and #60 of the ECM to operate the injector (inject the fuel). The SFI system produces control of fuel injection operation by the ECM in response to the driving conditions.
ESA (Electronic Spark Advance) System
The ESA system monitors the Engine condition through the signals which are input to the ECM from each Sensor (input signals from (1), (3), (4) to (12) etc.). The best ignition timing is decided according to this data and the memorized data in the ECM and the control signal is output to TERMINALS IGT1, IGT2, IGT3 and IGT4. 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 ECM evaluates the signals from each sensor (input signals from ((1), (4), (9) to (10) etc.), and outputs current to TERMINAL HTL, HTR and HTS, controlling the heater.
IAC (Idle Air Control) System
The IAC Valve (Rotary Solenoid Type) 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 ECM evaluates the signals from each sensor (input signals from ((1), (4), (5), (8), (9), etc.), outputs current to TERMINAL RSO and RSC to control Idle Air Control Valve.
Exhaust Gas Recirculation (EGR) Control System
The EGR Control System detects the signal from each sensor (input signals from ((1), (4), (9) (10) etc.), and outputs current to TERMINAL EGR to control the EGR Valve.
Acoustic Control Induction System (ACIS)
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 for increased engine output in all ranges from low to high speeds.
The ECM judges the engine speed by the signals ((4), (5)) from each sensor and outputs signals to the TERMINAL ACIS to control the VSV (for intake air control).
DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunction in the ECM signal system, the malfunctioning system is recorded in the memory.
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 ECM memory or else stops the engine.