Technology: The electronic control unit of your dirt bike!
Your dirt bike has also entered the era full of data, mappings, sensors, injection and other exotic conditions. Together with the arrival of fuel injection, the possibility was created to change the character of the engine using the computer. When the good old carburetor was commonplace, the ignition timing could only be controlled electronically. With electronic injection, the fuel injection can also be manipulated, opening up a whole new world for the rider and his mechanic.
This world is much more complicated than before and that is why MXMag provides clarity by explaining exactly what the whole business on your dirt bike is for.
- ECU or Electronic Control Unit: This is the control unit that determines how much and when fuel is injected through the injectors. The ECU also determines at what time the spark plug should produce a spark to ignite the gasoline mixture. This small computer is connected to the stator at various positions so that it constantly receives an update of the position of the crankshaft. The ECU is also connected to a number of external measuring units such as the MAP sensor, the TPS sensor, the IAT sensor and the ECT sensor. The computer of your dirt bike takes all this data into account and quickly calculates the necessary data. For comparison: On a motocross bike equipped with a carburetor, the only thing that is important is the ignition timing of the spark plug.
- Global setting: Your new dirt bike is delivered to the dealer with a global setting that works worldwide. The manufacturer thus ensures that the dirt bike works at any altitude, on any terrain, in any temperature and in any climate. Moreover, this global adjustment takes the quality of the fuel into account because it is not the same everywhere. In addition, various legislation regarding emission standards must also be taken into account. You understand that this global adjustment is an average and will never get all the power out of your motocross bike.
- The Voltage sensor: A current sensor is a device that detects electrical current in a wire and generates a signal proportional to that current. The generated signal can then be stored for further analysis in a data system. This data is therefore stored in the ECU.
- TPS sensor: Throttle Position Sensor or throttle position sensor. The word says it all: it checks the position of the throttle valve. The sensor is usually located on the shaft of the throttle valve. This determines the position of the throttle lever and sends it to the ECU.
- Lambda sensor: This sensor is located in the exhaust of the engine and determines the remaining oxygen content in the exhaust gas and provides the ECU with an electrical signal to regulate the mixture composition.
- IAT sensor: Intake Air Temperature sensor or air temperature sensor. This is located in the intake pipe after the air filter. This sensor has two functions: measuring temperature and air pressure and sending them to the ECU. The sensor regulates the amount of fuel depending on the heat of the sucked air. In warm weather it makes the mixture richer and in cold weather it makes it poorer. This is necessary because the density of the sucked air depends on the temperature. In warm weather, the air expands and therefore more fuel is needed to meet the ratio of 14 parts air to 1 part gasoline.
- ECT sensor or coolant temperature sensor. This sensor also has two functions. During a cold start, it temporarily makes the mixture richer to allow the engine to run properly. When an engine becomes too hot, the sensor can inject extra fuel to prevent damage from heat build-up. In an emergency, this sensor can switch off the engine if the temperature threatens to rise too high.
- MAP sensor or Manifold Absolute Pressure sensor. This sensor collects barometric data and thus adjusts the injection. In other words: It is this sensor that determines the height. If you are at sea level, the fuel injection will be different than in the Alps, for example. 1500 meters altitude.
- Many owners of a dirt machine do not pay much attention to the electronic components, but they are still very important for the proper functioning of the engine. Moisture is just about the biggest enemy of electronics. Therefore, regularly check the condition of the connectors. Blow them dry with compressed air after washing and spray them with contact spray. Corrosion of connectors and other electronic connections can lead to difficult-to-detect malfunctions.
Below you will see a video in which the difference between a carburetor and fuel injection is explained in detail.
Text: Danny Hermans
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