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US 6,644,029 B2Granted
Process for control of boost pressure limitation of a turbocharger in an internal combustion engine as a function of the density of ambient air
AssigneeAudi AG
InventorBernhard Weinreuter
Life of this patent
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Abstract
A process for the control of boost pressure of a turbocharger in an internal combustion engine as a function of the density of the ambient air. The internal combustion engine has an exhaust gas turbocharger with control means to control the boost pressure in which the actual boost pressure is determined at specific time intervals and compared with assigned values for the desired boost pressure taken from stored compressor characteristics. The boost pressure is adjusted as necessary. The internal combustion engine further comprises an engine control device having a control unit and a data storage unit.
Claims11
A process for controlling a boost pressure limitation of a turbocharger in an internal combustion engine as a function of the density of ambient air, comprising the steps of:
- determining actual values of the ambient temperature (T∞), the ambient pressure (P∞), and a value of an air mass (mL) drawn in;
- determining values of a boost pressure (PList) at downstream of a compressor in an operating condition at assigned time intervals;
- determining actual values of a pressure (PVE) at a compressor intake and a temperature (TVE) at the compressor intake by way of an air mass predetermined value dependent on correction curves;
- adjusting an air mass throughput (mLkor) at the compressor intake to standard conditions from the pressure (PVE) determined at the compressor intake, from the temperature (TVE) determined at the compressor intake, and from the determined air mass (mL) drawn in, respectively;
- comparing a maximum permissible compressor speed dependent on an adjusted maximum permissible boost pressure (PLmaxkor), taken respectively from a compressor characteristics being a maximum compressor speed (nVmax) for adjusting the permissible air mass throughput (mLkor) to standard compressor conditions at the compressor intake and the ambient pressure determined (P∞), to the boost pressure (PList) determined in an operating condition;
- and controlling the boost pressure (PList) so that a maximum value in each instance determined for the boost pressure (PList) corresponds to the adjusted maximum permissible compressor speed dependent boost pressure (PLmaxkor) determined in this state.
3 more elements
An internal combustion engine with an exhaust gas turbocharger and a control device for adjusting a boost pressure for which respectively an actual boost pressure is determined and compared with assigned values in a respective operational state taken from a stored compressor characteristics, wherein:
- the control device is in data connection with means for determining a value of the ambient temperature (T∞), a value of the ambient pressure (P∞) from an air mass drawn in (mL), and a value of the boost pressure (PList);
- the control device has means for recording such data at assigned intervals;
- the control device is in data connection with a databank for storing a predetermined air mass value dependent on correction parameters of the boost pressure (Kp) and the temperature (KT) at the compressor intake of the turbocharger and with the stored compressor characteristics with respective predetermined relationships between the air mass drawn in (mL) and a ratio of boost pressure to ambient pressure (PList/P∞) at various compressor speeds (nV) and at a maximum permissible compressor speed (nVmax) of the turbocharger;
- wherein the control device has means:
- for respectively determining a value of a pressure (PVE) at a compressor intake from the ambient pressure (P∞) and a corresponding boost pressure correction parameter (Kp) of the pressure (PVE) at the compressor intake,
- for respectively determining a value of the temperature (TVE) at the compressor intake from the ambient temperature (T∞) determined and a corresponding temperature correction parameter (KT),
- for respectively determining an actual value of an adjusted air mass throughput (mLkor) at the compressor intake from the air mass drawn in (mL), from the pressure (PVE) as determined at the compressor intake and from the temperature (TVE) as determined at the compressor intake,
- for respectively determining a maximum permissible boost pressure (PLmax) of the adjusted maximum permissible air mass throughput (mLkor) from the compressor characteristics being a maximum permissible compressor speed (nVmax) at the compressor intake, and from the ambient pressure (P∞) as determined, and
- for respectively comparing the boost pressure (PList) as determined with the respective compressor speed dependent maximum permissible boost pressure (PLmax);
- and
- the control device is connected to a means for building-up and modifying the boost pressure, and
- the control device has a control mechanism for setting an upper limit of built-up boost pressure, wherein the control mechanism acts on the means for building-up and modifying the boost pressure so that the boost pressure (PList) does not exceed an determined maximum permissible boost pressure (PLmaxkor).
9 more elements
An engine control device for an internal combustion engine with an exhaust gas turbocharger, a control unit for controlling the boost pressure and a databank,
- wherein the control unit records data regarding a value of the ambient temperature (T∞), a value of the ambient pressure (P∞), a value of the air mass (mL) drawn in, and a value of the boost pressure (PList) at assigned time intervals;
- wherein the control unit is data connected for data acquisition to the databank to store a predetermined air mass dependent on correction parameters for the boost pressure (Kp) and the temperature (KT) at a compressor intake of the turbocharger and a stored compressor characteristic with the respective predetermined relation at various compressor speeds (nV) and at a maximum permissible compressor speed (nVmax) of the turbocharger, between air mass (mL) drawn in and the ratio of the boost pressure to the ambient pressure (PList/P∞),
- wherein the control unit has means
- for respectively determining a value of a pressure (PVE) at the compressor intake from the data acquired for the ambient pressure (P∞) and the corresponding boost pressure correction parameter (Kp) of the pressure (PVE) at the compressor intake,
- for respectively determining a value of a temperature (TVE) at the compressor intake from the data acquired for the ambient temperature (T∞) and the corresponding temperature correction parameter (KT),
- for respectively determining an actual value of the actual value for an adjusted air mass throughput (mLkor) at the compressor intake from the data acquired for the air mass (mL) drawn in as determined, from the pressure (PVE) as determined at the compressor intake and from the temperature (TVE) as determined at the compressor intake,
- for determining a maximum permissible boost pressure (PLmax) for the adjusted air mass throughput (mLkor) at the compressor intake from the compressor characteristics being the maximum permissible compressor speed (nVmax) at the compressor intake and from the ambient pressure (P∞) as determined, and
- for respectively comparing the boost pressure (PList) as determined with a respective compressor speed dependent on the maximum permissible boost pressure (PLmax);
- and
- the control unit has a data connection for transmitting data to means for building-up and modifying the boost pressure;
- and
- the control unit has a control mechanism for setting an upper limit of a built-up boost pressure, wherein the control mechanism generates control data acting on the means for building-up and modifying the boost pressure so that the compressor speed dependent on the maximum permissible boost pressure (PLmax) will not be exceeded.
9 more elements
Dependencies are inferred from the claim text.