System Description
INPUT/OUTPUT SIGNAL CHART
| Sensor | Input signal to ECM | ECM function | Actuator |
|---|---|---|---|
| Crankshaft position sensor | Engine speed *1 Piston position |
Ignition timing control | Ignition coil (with power transistor) |
| Camshaft position sensor | |||
| Mass air flow sensor | Amount of intake air | ||
| Engine coolant temperature sensor 1 | Engine coolant temperature | ||
| Throttle position sensor | Throttle position | ||
| Accelerator pedal position sensor | Accelerator pedal position | ||
| TCM | Gear position | ||
| Battery | Battery voltage *1 | ||
| Knock sensor | Engine knocking condition | ||
| Combination meter | Vehicle speed *2 |
* 1: ECM determines the start signal status by the signals of engine speed and battery voltage.
* 2: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
Ignition order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised by the ECM according to the other data stored in the ECM.
- At starting
- During warm-up
- At idle
- At low battery voltage
- During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition. The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.