Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Patent
1997-03-25
2000-02-01
Koczo, Michael
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
F02B 3712
Patent
active
060189487
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND INFORMATION
The present invention relates to a device for lowering the boost pressure of a turbocharger in an internal combustion engine having a turbocharger in order to reduce engine torque.
A device of this kind is disclosed by the German Patent 32 24 254 C2. Under this prior art, the boost pressure is lowered and/or cylinders are selectively suppressed to limit engine torque or to reduce it until no more tire slip occurs, regardless of how heavily the driver of a vehicle is pressing down on the accelerator. The engine torque is controlled here in open-loop as a function of the detected tire slip. Under this prior art, the engine torque is controlled in open-loop as a function of only one single variable that characterizes vehicle performance, namely tire slip.
SUMMARY OF THE INVENTION
The object of the present invention is to disclose a device of the type mentioned at the outset, which will be able to control the engine torque in open or closed loop as a function of a plurality of influencing parameters.
To achieve this objective, the device according to the present invention lowers the boost pressure as a function of a defined setpoint engine torque when the setpoint engine torque or a setpoint engine performance quantity associated therewith is smaller than a corresponding engine performance quantity that is specified without intervening in the boost pressure. Accordingly, it is also possible to promote engine torque reduction, as well as the lowering of boost pressure, through cylinder suppression and/or ignition timing intervention.
Because a specified setpoint engine torque is retrieved as a controlled or directly controlled variable for engine torque, a plurality of variables that influence engine or vehicle performance can be considered. Thus, for example, the setpoint engine torque can be derived from a traction control system (TCS) or represent a controlled or directly controlled variable, which results from the requirement for a rotational speed or velocity limitation or for a gear speed change intervention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a flow chart of a first exemplary embodiment of the present invention.
FIG. 2 shows a flow chart of a second exemplary embodiment of the present invention.
FIG. 3 shows a block diagram of an engine in cooperation with a turbocharger and a device for lowering the boost pressure of the turbocharger in accordance with the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
The present invention will be elucidated in the following on the basis of two exemplary embodiments illustrated in the drawings. FIG. 1 shows a flow chart for controlling the boost pressure of an internal combustion engine; and FIG. 2 a flow chart for controlling the boost pressure in closed loop. FIG. 3 shows a block diagram of an engine 100 in cooperation with a turbocharger 110 and a device for reducing the boost pressure of the turbocharger 120.
The exemplary embodiments relate to a device, which, given an internal combustion engine having a turbocharger, so controls the boost pressure of the turbocharger in open loop or closed loop that the engine torque is reduced to a predetermined setpoint engine torque.
FIG. 1 depicts the functional sequence of a control device, which makes available a setpoint engine torque MMS as a reference variable. This setpoint engine torque MMS can be derived, for example, from a traction control system, which defines a setpoint engine torque required to avoid a tire slip. This setpoint engine torque MMS is compared to an engine torque MMFA that is measured or estimated without intervening in the boost pressure. If this engine torque MMFA is greater than the specified setpoint engine torque MMS, then the boost pressure is lowered to its basic value. The basic value is a fixed value, which corresponds to the smallest possible boost pressure. Since the lowering of the boost pressure and the resultant change in the charge in the cylinders of the internal combustion engine (that is the air mass per cylinder stroke) proceed
REFERENCES:
patent: 5083434 (1992-01-01), Dahlgren et al.
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patent: 5213178 (1993-05-01), Polidan et al.
patent: 5365908 (1994-11-01), Takii et al.
Schnaibel Eberhard
Steinbrenner Ulrich
Wagner Wolfgang
Zhang Hong
Koczo Michael
Robert & Bosch GmbH
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