Quantity control for part load/full load, function

The fuel quantity for partial load or full load is primarily adjusted according to the demands of the driver.

If the specified engine torque from the driver changes in that he, for example, presses on the accelerator pedal, the engine control (MR) alters the fuel quantity (via the delivery angle) as much as possible to ensure that the resultant torque is exactly the value of the engine torque requested by the driver.

Limitation of the specified engine torque, for example to maintain the legally prescribed maximum vehicle speed, on the basis of regulating interventions made by the Antilocking system (ABS) or the Acceleration Slip Regulation (ASR) or to protect the engine from damage, leads to limitation of the fuel quantity and thus a respective alteration of the delivery angle.

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The delivery angle, which is determined over performance maps in the MR/PLD control unit , is dependent on the following input factors:

 Engine speed

 Air mass

 Engine temperature

 Fuel temperature

Only altitude correction and smoke imitation in the engine control (MR) can additionally effect the delivery angle:

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Altitude correction

Within the MR/PLD control unit there is an atmospheric pressure sensor. It determines the air pressure of the ambient air from which the engine control (MR) deduces an altitude correction.

The altitude correction prevents too much fuel being injected at high altitudes.

Smoke limit

The fuel quantity is limited via the smoke limitation characteristics so that virtually no output of smoke occurs.