초록 ▼

An engine control system for protecting a turbocharger of an internal combustion engine from an overspeed condition occurring as a result of a failure of the turbocharger wastegate device. In one embodiment of the invention, sensors provide signals for engine speed, ambient pressure and boost pressu

An engine control system for protecting a turbocharger of an internal combustion engine from an overspeed condition occurring as a result of a failure of the turbocharger wastegate device. In one embodiment of the invention, sensors provide signals for engine speed, ambient pressure and boost pressure between the turbocharger and the engine intake. Correction factors are added to the boost pressure and ambient pressure signals, and a turbocharger pressure ratio is calculated from these signals. A reduced fueling table maps turbocharger pressure ratio and engine speed to reduced fueling signal values. An engine control computer utilizes a nominal fueling table that maps engine speed and boost pressure to nominal fueling signal values. The control computer also includes a decision module that selects the lesser of the nominal fueling signal values and the reduced fueling signal values and provides the selected value to the engine fueling system. In the event of a wastegate failure, the turbocharger wheelspeed will increase, followed by an increase in boost pressure. However, not all boost pressure increases are detrimental to the turbocharger (i.e., lead to excessive speed), so the present invention evaluates the turbocharger pressure ratio to determine when an excessive speed condition exists. If such a condition exists, the engine control computer selects the lesser fueling signal value from the reduced fueling table to decrease fueling to the engine, and ultimately to decrease the engine speed and load. The decreased engine speed and load reduces the exhaust gas mass flow rate, which reduces the turbocharger rotational speed to an acceptable level.

대표청구항 ▼

[ What is claimed is:] [1.] An engine control system for an internal combustion engine having a turbocharger driven by engine exhaust and providing a pressurized charge of air to the engine intake manifold, comprising:a fuel system operable to supply fuel to the engine in response to a fueling signa

[ What is claimed is:] [1.] An engine control system for an internal combustion engine having a turbocharger driven by engine exhaust and providing a pressurized charge of air to the engine intake manifold, comprising:a fuel system operable to supply fuel to the engine in response to a fueling signal;a control computer operable to generate nominal fueling signals according to a nominal operating condition for the engine;means for determining the pressure ratio of the turbocharger and providing a pressure ratio signal corresponding thereto;means for determining engine speed and providing an engine speed signal corresponding thereto; andmeans for reducing the rotational speed of the turbocharger by generating modified fueling signals, different from said nominal fueling signals, as a function of said pressure ratio signal and said engine speed signal.