Chapter 10 Engine Management Unit; Section 1 System Description - Geely CK Series 2007 Workshop Manual

Chapter 10 Engine Management Unit

Section 1 System Description

Engine Control System generally consists of sensor, controller and actuator.
Sensor: convert the physical parameter of the device into electric signal (digital or analog) to monitor the
operating condition of the device and send these signals to the controller.
Controller: receive and process information sent from the sensor, and analyze the information to learn the
conditions of the device: use predefined control strategy and procedure, determine how to control the device
under current conditions; convert the decision into one or more orders and send them to the actuator. The
controller contains a microprocessor and stores pre-developed the programs or control software in the memory.
The controller can be regarded as the brain of the control system.
Actuator: receive orders from the controller, covert the electric signal into the action of the actuating ele-
ments (either action of electric element or mechanical movement). The actions of these elements will change
the operating conditions of the device and determine the operation and output of the device.
Large amount of information flows through the entire control system. Engine Control Unit learns the opera-
tion of the device from the information sent from the sensor, determines the approach and orders of the
control with the input and information stored by itself and ends up in sending the information about the orders
to the actuator.
I. Engine Fuel System Electronic Control System
Engine fuel system electronic control focuses on the quantified electronic control of the fuel, and actually is
the electronic control over the excessive air coefficient .
ECU controls the by controlling the fuel injection. When the engine is running, ECU receives the informa-
tion about the air flow from the sensor and determines the fuel injection by calculations to make the excessive
air coefficient of the mixed air reach the predefined value. The control order output by ECU is only a control
signal to trigger the injector. ECU output the pulse width and timing in this signal.
The pulse width of injection signal determines the fuel amount of the injection. The pulse is the function of the
following parameter. The input and output are modified into closed loop control.
ECU calculate the target - air fuel ratio.
Air flow value.
Other operating conditions of the engine, such as throttle position sensor, exhaust manifold oxygen sensor.
low feature of the injector.
Engine ignition system electronic control
The control of Engine Control Unit over the ignition includes ignition advance angle control, knock control and
ignition power control (dewell angle control).
The control over the ignition advance angle is the basic function of the ignition control. Ignition advance angle
= ignition advance angle basic value + correction.
The control over the ignition advance angle also relates to the operating conditions of the engine. The factor
varying with the operating conditions can be reflected by the correction factor.
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