The ECM is like the soul of the engine, controlling the operation of the entire engine. To control the entire engine, many sensors must be used to receive and transmit engine operating information. After calculation of these engine operating information, the ECU will send control signals to each actuator to control the actuator's action.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
ECM (Engine ControlModule) is like the soul of the engine, controlling the operation of the entire engine.
To control the entire engine, there must be many sensors (Sensors) to receive and transmit engine operating information. An engine usually has an intake air temperature sensor (IAT Sensor) and a throttle opening sensor (TPS Sensor). , manifold pressure sensor (MAP Sensor), water temperature sensor (ECT Sensor), crankshaft angle sensor (Crank Sensor), knock sensor (Knock Sensor), oxygen sensor (O2 Sensor), etc., send various engine status information to the ECU (Engine Control Unit) performs calculations. After these engine operating information are calculated, the ECU will send control signals to each actuator (Reactor) to control the action of the actuator. Common actuators on the engine include the idle control valve. (IAC), fuel injection module, ignition module, EGR valve, VVT controller, activated carbon canister (EEC) degassing valve, etc.
Perhaps readers will be dazzled by this, but with so many sensors and so many actuators, the most important thing is actually to calculate and control the optimal fuel injection amount and ignition timing of the engine, and of course There are some controls to comply with environmental regulations, such as the activated carbon canister degassing valve.
Controls such as ignition, idle speed, timing, knocking and fuel injection have been introduced in various relevant units. This article will talk about "open loop control" and "closed loop control" related to fuel consumption. . In "control science", the so-called "open loop control" means that the controller gives one-way instructions to the actuator to operate according to the written control mode; while "closed loop control" adds feedback to the control loop. signal to correct the amount of movement of the actuator. In the fuel injection control system, the ECU transmits the fuel injection amount command set under the conditions to the fuel injector according to the current engine operating conditions. Under open-loop control, the injection command sent by the ECU to the injector will not be modified by the feedback signal.
Under closed-loop control, the fuel injection command will be modified by the feedback signal, and the source of the feedback signal is the oxygen sensor. The oxygen sensor will detect the oxygen content in the exhaust gas and send the oxygen content signal to the ECU. The ECU will calculate the actual air-fuel ratio based on the oxygen content and fuel injection volume. If it detects that the mixture is too lean (air-fuel ratio If the mixture is detected to be too rich (the air-fuel ratio is small), the ECU will correct it in the lean direction to allow the engine to run at the optimal air-fuel ratio. At this time, the engine's fuel consumption will be the smallest.
When will the engine be in closed loop control and when will it be in open loop control? Under normal operating conditions, the engine uses closed-loop control. However, when the accelerator opening is too large, rapid acceleration, or cold engine conditions, the engine will enter an open-loop state. Especially when you step on the accelerator, the engine is not only in an open circuit state, but also enters the fuel injection enrichment mode, so it must consume more fuel. Oil prices are rising steadily. The best way to save fuel is to exercise restraint!
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