초록 ▼

An electronic control for a variable displacement turbocharger (VGT) determines the desired operation of the VGT in accordance with vehicle and engine operating conditions, and positions the VGT control arm to achieve the desired operation. When the engine is operating in a vacuum mode, the control

An electronic control for a variable displacement turbocharger (VGT) determines the desired operation of the VGT in accordance with vehicle and engine operating conditions, and positions the VGT control arm to achieve the desired operation. When the engine is operating in a vacuum mode, the control arm is adjusted in open loop fashion; when the engine should be operating in a boost mode, the control arm is adjusted in a closed loop fashion according to the difference between the actual and desired boost.

대표청구항 ▼

In a motor vehicle power plant including a combustion engine, an engine exhaust gas driven turbocharger adapted to boost the pressure of a combustible mixture supplied to the engine, and an adjustable turbocharger control mechanism for effectively varying the turbocharger geometry to provide increas

In a motor vehicle power plant including a combustion engine, an engine exhaust gas driven turbocharger adapted to boost the pressure of a combustible mixture supplied to the engine, and an adjustable turbocharger control mechanism for effectively varying the turbocharger geometry to provide increased or decreased boost for a given engine operating condition, a method of adjusting the control mechanism, comprising the steps of: sensing the actual pressure of the combustible mixture supplied to the engine; determining based on said sensed pressure whether the engine is operating in a vacuum mode wherein the pressure of the mixture is less than atmospheric pressure, or a boost mode wherein the turbocharger boosts the pressure of the mixture above atmospheric pressure; generating a control signal in accordance with sensed engine and vehicle conditions, the control signal having a characteristic representative (1) of a desired turbocharger geometry for satisfying engine performance and efficiency criteria when the sensed conditions indicate that the engine should be operating in the vacuum mode, and (2) of the desired pressure of the combustible mixture when the sensed conditions indicate that the engine should be operating in the boost mode; and controlling the turbocharger geometry by open loop adjustment of the control mechanism in accordance with the control signal characteristic when it is determined that the engine is operating in the vacuum mode and by closed loop adjustment of the control mechanism in accordance with the difference between the desired pressure represented by the control signal characteristic and the sensed pressure when it is determined that the engine should be operating in the boost mode.