초록 ▼

The present invention is an apparatus for controlling a variable geometry turbocharger (VGT) in closed loop and open loop modes, and a switching mechanism for determining whether open loop or closed loop control laws should be used. In the closed loop mode, a correction factor, obtained from a press

The present invention is an apparatus for controlling a variable geometry turbocharger (VGT) in closed loop and open loop modes, and a switching mechanism for determining whether open loop or closed loop control laws should be used. In the closed loop mode, a correction factor, obtained from a pressure correction map based on engine speed and atmospheric pressure, is subtracted from the desired boost pressure to prevent overspeed of the turbocharger at lower atmospheric pressures. The actual boost pressure is then compared to the desired boost pressure after correction to obtain a boost pressure error signal. The boost pressure error signal is used as an input to a proportional integral differential control law that responsively produces a desired VGT vane position. A minimum limit on the desired VGT vane position is based on engine speed and fuel quantity, whereas a maximum allowable vane position may be a predetermined constant or function. A linearization map is used to obtain a VGT current signal that is transmitted to an actuator for moving the vane position.

대표청구항 ▼

[ What is claimed is:] [1.]1. An apparatus for controlling a variable geometry turbocharger, comprising:a first sensor operable to provide an engine speed signala second sensor operable to provide a fuel quantity signal;a data processor coupled with the first and second sensors to receive the engine

[ What is claimed is:] [1.]1. An apparatus for controlling a variable geometry turbocharger, comprising:a first sensor operable to provide an engine speed signala second sensor operable to provide a fuel quantity signal;a data processor coupled with the first and second sensors to receive the engine speed signal and the fuel quantity signal, the data processor operable to store at least one engine operating map including a desired boost pressure map, the desired boost pressure map being a function of engine speed and fuel quantity, the data processor being further operable to generate a desired boost pressure signal based on the desired boost pressure map, the engine speed signal, and the fuel quantity signal;a closed loop control circuit coupled with the data processor to receive the desired boost pressure signal, the closed loop control circuit operable to generate a first desired nozzle vane position based on the desired boost pressure signal;an open loop control circuit coupled with the first and second sensors to receive the engine speed and the fuel quantity signals, the open loop control circuit operable to generate a second desired nozzle vane position based on the engine speed signal and fuel quantity signals; anda switching circuit coupled with the first and second sensors and the closed and open loop control circuits, the switching circuit operable to transmit one of the first and second desired nozzle vane positions as a function of the engine speed and the fuel quantity;wherein the data processing means is further operable to generate a corrected desired boost pressure signal by summing the desired boost pressure signal with a boost pressure correction signal, the boost pressure correction signal being generated from a boost pressure correction map, the engine speed signal, and an atmospheric pressure signal from an atmospheric pressure sensor.