Internal-combustion engines – Combustion chamber means having fuel injection only
Reexamination Certificate
1999-10-01
2001-03-27
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Combustion chamber means having fuel injection only
C123S295000, C123S350000, C701S102000
Reexamination Certificate
active
06205973
ABSTRACT:
BACKGROUND OF THE INVENTION
U.S. Pat. No.
6,092,597 discloses a control system for an internal combustion engine having gasoline direct injection. In this control system, the fuel mass, which is to be injected, is determined from a desired value for the torque of the engine. A procedure is also presented with which this engine can be switched over between the different modes of operation. The most essential modes of operation of such an engine are an operation of the engine with charge stratification in an almost unthrottled operation as well as a throttled operation of the engine with homogeneous injection. For an engine having gasoline direct injection, it is important to determine the actual torque of the engine. This value is, for example, outputted to other control units (for example, a drive slip control) for further evaluation or is evaluated within the control system, for example, for initializing filters and, if required, for monitoring, et cetera.
U.S. patent application Ser. No. 254,582, filed Jul. 1, 1998 (German patent publication 197 29 100) discloses a model for determining the torque of an internal combustion engine having gasoline direct injection. In this model, the actual combusted fuel mass is determined on the basis of the inducted air mass, the returned exhaust-gas mass, the oxygen concentration of the exhaust gas and a conversion factor. The actual torque of the engine is derived from this computed combusted fuel mass. It has been shown that the application of this model leads, in some cases, to unsatisfactory results because additional quantities, which operate on the torque, are not considered. Furthermore, this model is not consistent. This means that the actual torque can be determined but the inversion of the model (that is, the computation of the actuating quantities of the engine in dependence upon the desired torque) is not ensured. For this reason, various models are used to determine the actual torque and to convert the desired torque so that the complexity with respect to the control of the engine is increased.
U.S. Pat. No. 5,692,471 discloses a consistent torque model with reference to an internal combustion engine having intake manifold injection. There, the torque of the engine is computed from an optimal torque, which defines the maximum torque of the engine under standard conditions, as well as from degrees of efficiency with respect to the mixture composition, the ignition angle adjustment, and the suppression of fuel injections. The optimal torque is determined in dependence upon engine rpm and engine load (charge). With the efficiencies, the influences of the deviations of the actual values from the standard conditions, which form the basis of the formation of the optimal torque, are considered. With a corresponding inversion of the model, not only the actual torque of the engine can be determined from the actuating quantities, but also the actuating quantities can be determined in dependence upon a desired torque value. This model is not limited to an engine having gasoline direct injection because additional or changing requirements are to be considered as a consequence of the different modes of operation.
SUMMARY OF THE INVENTION
It is an object of the invention to provide measures for determining the actual torque of the internal combustion engine having gasoline direct injection.
The method of the invention is for determining the actual torque of an internal combustion engine having gasoline direct injection. The method includes: computing the torque of the engine with a model in dependence upon operating variables; specifying a value for the maximum torque, which would be achieved under standard conditions, from a pregiven characteristic field in dependence upon operating variables which characterize an operating point of the engine; inputting an efficiency for at least one torque-influencing actuating variable of the engine with the efficiency being formed in dependence upon a current or present value of the actuating variable and a standard value of the actuating variable; and, correcting the maximum torque with the efficiency to determine the actual torque.
A model for determining the torque of the engine is determined for the almost unthrottled operation of an engine with direct injection. With this model, the individual influences on the engine torque are separated. In this way, it is possible to consider all influence quantities on the torque of the engine in a simple manner. The computation steps, which are necessary for computing the torque, are reduced. Furthermore, it is advantageous that cross-couplings of the actuating quantities, for example, throttle flap position, ignition time point, injection time, et cetera, are eliminated when these actuating quantities influence the engine torque. In addition, the particular equipment of the engine can be considered for the computation of a model in a simple manner. The particular equipment of the engine, for example, can be with or without a swirl flap, cam shaft adjustment, et cetera.
It is especially advantageous that the model is consistent, that is, that the computation of the actual torque can be carried out from measured values of the torque-influencing parameters as well as that the computation of actuating quantities for these parameters can be carried out for a required torque with a unitary model.
It is especially advantageous that the torque model, which has been shown suitable for the determination of the actual torque of an engine having gasoline direct injection for the almost unthrottled operation of the engine, has the corresponding structure as the torque model for the computation of the actual torque for an engine having intake manifold injection and homogeneous fuel mixture formation. In this way, a single torque model can be used for determining the actual torque or for determining the actuating variables for an engine having gasoline direct injection in all modes of operation independently of whether throttled or not. Only individual model parameters are to be switched over between unthrottled and throttled operation of the engine.
REFERENCES:
patent: 5692471 (1997-12-01), Zhang
patent: 5692472 (1997-12-01), Bederna et al.
patent: 5755198 (1998-05-01), Grob et al.
patent: 6092507 (2000-07-01), Bauer et al.
patent: 6116210 (2000-09-01), Oder et al.
Bauer Hartmut
Gerhardt Jurgen
Hess Werner
Kohler Christian
Oder Michael
Argenbright Tony M.
Ottesen Walter
Robert & Bosch GmbH
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