Control of a variable geometry turbocharger by sensing exhaust pressure

摘要

There is provided a system and method for using an engine's exhaust back pressure to control a variable geometry turbocharger. The control system determines a desired exhaust back pressure based on engine speed and engine load. The desired exhaust back pressure is compared with a measured exhaust back pressure to determine the difference between the measured and desired exhaust back pressures. The difference value is used to determine the duty cycle. In an alternate embodiment, the exhaust gas pressure is used to adjust the duty cycle determined by other operating parameters. A base duty cycle is determined from the engine speed and the engine load. The difference between the measured and desired exhaust back pressures is used to determine an exhaust pressure control duty cycle. The base duty cycle is then adjusted by the exhaust pressure control duty cycle to give a turbocharger duty cycle.