Method and system for controlling engine torque reserve

Abstract

The disclosure provdies a method and a system for controlling engine torque reserve. Methods and systems are provided for providing torque reserve via an electrically assisted turbocharger. A portionof requested torque reserve is provided by intentionally reducing turbine speed of an electric turbocharger by operating the associated electric motor as a generator. The resulting reduction in air mass allows for the torque reserve to be provided with reduced reliance on spark and throttle based torque reserve.

Description

technical field [0001] The present description generally relates to methods and systems for controlling a vehicle engine to vary torque reserve contributions from spark, throttle, and electrically assisted turbocharger adjustments. Background technique [0002] Internal combustion engines combust an air and fuel mixture within cylinders to produce engine torque. During part load conditions, a certain percentage of engine torque may be held in reserve (referred to as a torque reserve) to improve the immediate response of the engine during momentary increases in torque demand. In the absence of torque reserve, engine response time may be slower and drivability may be adversely affected. [0003] The engine control system may provide the desired torque reserve by adjusting one or more torques that affect engine parameters such as engine airflow and spark timing. Partially closing the intake throttle reduces the amount of air available to the engine for combustion, creating an...

AI Technical Summary

Problems solved by technology

However, if the actual increase in the requested torque is smaller or slower, the torque is wasted

Specifically, spark reserves may be overscheduled, and since spark reserves are immediate, there may be a loss of efficiency if not all reserves are used

As another example, the use of any torque reserve sacrifices engine efficiency for manoeuvrability during part load operation

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