Automotive Electronics - Engine Electronics

Engine Electronics

One of the most demanding electronic parts of an automobile is the engine control unit. Engine controls demand one of the highest real time deadlines, as the engine itself is a very fast and complex part of the automobile. Of all the electronics in any car the computing power of the engine control unit is the highest, typically a 32-bit processor.

It controls such things as:

In a diesel engine:

• Fuel injection rate
• Emission control, NOx control
• Regeneration of oxidation catalytic converter
• Turbocharger control
• Cooling system control
• Throttle control

In a gasoline engine:

• Lambda control
• OBD (On-Board Diagnostics)
• Cooling system control
• Ignition system control
• Lubrication system control (only a few have electronic control)
• Fuel injection rate control
• Throttle control

Many more engine parameters are actively monitored and controlled in real-time.

There are a lot of sensors — about 20 to 50 — which measure pressure, temperature, flow, engine speed, oxygen level and NOx level plus other parameters at different points within the engine. All these sensor signals are sent to the ECU, which has the logic circuits to do the actual controlling. The ECU output is connected to different actuators for the throttle valve, EGR valve, rack (in VGTs), fuel injector (using a pulse-width modulated signal), dosing injector and more. There are about 20 to 30 actuators in all.