摘要 |
<p>A control system for a variable geometry turbocharger having a turbine driven by exhaust gas delivered to an exhaust gas inlet of the turbocharger from an engine exhaust manifold and a compressor driven by the turbine to deliver air to an engine intake manifold via an air outlet of the turbocharger. The differential pressure across the engine is monitored, and a closed loop control system adjusts the variable geometry mechanism to prevent the differential pressure exceeding a predetermined limit. In engine braking mode the variable geometry mechanism may be actuated by a signal representative of the exhaust manifold pressure. An override circuit may be provided to control the variable geometry mechanism in the event of the turbocharger rpm exceeding a predetermined limit.</p> |