Electronic Engine Control Units
The ECU (engine control unit) is a computer controlling the fuel injection system on modern petrol and diesel engines.
In order to control engine performance the ECU uses information collected from various sensors to control the mixing of air and fuel to provide power.
This process can be optimised for maximum power, maximum fuel economy, optimal acceleration from stationary and any other conceivable set of parameters.
Engine Power
The primary or deciding factor in engine performance involves controlling and maximising the amount of air-oxygen that we can squeeze into the combustion chamber.
Air is a gas with a pretty constant 20.9% Oxygen. The amount of oxygen in every litre of gas varies with atmospheric pressure and temperature.
This means that a high performance car driving at sea level and 0 Deg Celsius should generate more power than the identical car running at high altitude and 35 deg Celcius
Temperature Sensor Air Intake and Engine Temperature
So the first input sensor measurement is air intake temperature. Using this figure, the ECU can look-up in an electronic table pre-programmed by the manufacturer an estimate of the amount oxygen that is available for combustion. In the same instant, it can calculate the amount of fuel that can be injected for the most efficient combustion.
Immediate Feedback - The Lambda Oxygen Sensor
After ignition, the exhaust gases are vented from the combustion chamber where they pass over an Oxygen Sensor or Lambda Sensor
This gives a very good indication of the amount of fuel that has been burnt and if the air-fuel mixture entering the chamber is too rich or too lean.
Within a fraction of a second the ECU will recalculate a new optimal fuel quantity and feedback this information to the fuel injection system.
Engine Revolution and Speed Torque Variation
Driving performance is not about driving at constant speed but driving optimally for speed, acceleration, fuel economy under variable load conditions so keeping the engine running at the ideal would most likely cause flat spots, acceleration lag and a very rough driving experience.
When accelerating and while the engine is warming up the ECU knows to use a richer fuel-air mixture to prevent engine hesitation.
Performance Management
The ECU fitted in a normal road vehicle is mapped with a series of lookup tables to provide high fuel economy low emission driving under a variety of driving conditions
It is possible to replace the look-up table or Remap the ECU for a new set of parameters and customise the driving experience to race or sport driving conditions
Specialist replacement ECU chips are available from GEMS and OMEX for advanced performance tuning.
North East ECU Fitting and Mapping ReMapping Experts
At Autolink Garage we have the Road and Rally Experience to Modify, Re-Chip and Map your Engine for superlative and responsive performance improvements.