Powertrain Management: Description and Operation

Engine Management System
The ECM controls the engine management system. The system consists of an engine control module (ECM) and a number of sensing and actuating devices. The sensors supply the ECM with input signals, which relate to engine operating conditions and driver requirements. The ECM using calibrated data-tables and maps evaluates the sensor information. The ECM then uses the results to command an appropriate response from the actuating devices. The system provides the necessary engine control accuracy and adaptability to:
- Minimize exhaust emissions and fuel consumption;
- Provide optimum driver control under all conditions;
- Minimize evaporative fuel emissions;
- Provide system diagnostics when malfunctions occur.

In addition to these functions the ECM also interfaces with other vehicle systems through the CAN network.

The 32-bit ECM is at the center of the system and provides the overall control. Its function are listed below, each of which are dependent on the engine and vehicle state at any moment of time and driver requirements.
- Starting: Ensures that conditions are safe to crank the engine.
- Engine: Controls the rate of air and fuel flow into the cylinders; adjusts the intake manifold volume; controls the ignition and intake camshaft timing.
- Fuel supply: Controls the operation of the fuel pumps and vapor purge valve.
- Cooling: Controls the engine cooling fans
- Battery: Optimizes the battery charging conditions.
- Air conditioning and screen heater: Controls the speed of the engine when these additional loads are added, also disables the air conditioning when it is beneficial to reduce the load on the engine.
- Speed control: Provides the option to maintain a fixed vehicle speed without driver intervention.
- Robustness: Maintains engine-running condition under intermittent or permanent single point failures on any sensors or actuators fitted to the system, and records fault codes of these failures for system diagnosis.
- Diagnosis: Notifies the driver when a system malfunction occurs and records data for system diagnosis.