Diesel Electronic Control Systems

Increasingly stringent emission standards have made better control of the diesel combustion process necessary. Electronically controlled diesel systems give very precise control of the fuel injection and combustion process. Electronic controls have delivered other benefits besides a reduction in fuel consumption and emissions. These benefits include an increase in power and torque and improved engine responsiveness. Other benefits include a reduction in engine noise and diesel knock and improved and expanded diagnostic capabilities through the use of scan tools.

Diesel electronic control systems monitor and control many variables. Engine speed is one variable controlled to maintain a smooth functional idle and to limit the maximum engine speed, power, and torque to keep the engine output within safe limits. Another variable controlled is the fuel injector operation, including the timing, rate, and volume of fuel injected. Additionally, exhaust gas emissions are analyzed to determine combustion efficiency and pollutant levels.

An electronic communications network, called the data bus, allows exchange of data between computers. It is necessary for efficient operation and fault diagnosis. Modern diesel vehicles often operate with several computers, or processing units. These computers are used for different functions of vehicle operation. They can include computers specifically used to control the engine, transmission, and body systems.

These computers require extremely prompt communication with each other and function within a hierarchy of operation. For example, when you consider vehicle stability control, anti-lock braking, airbag deployment, and engine operation, which computer data are most import, and in what order? How fast is the information needed? You can see why a computer data bus network is important to manage communication between the vehicle’s computers.