Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
1999-02-05
2001-04-24
Yuen, Henry C. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C701S104000, C701S103000, C123S480000, C123S494000
Reexamination Certificate
active
06223121
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a gasoline engine (internal combustion engine) of a fuel injection control type. More particularly, the present invention relates to an improved air-to-fuel ratio control device which is capable of controlling an air-to-fuel ratio of the engine by applying a neural network which stores knowledge(information) and operates adaptively to aims or environments.
BACKGROUND OF THE INVENTION
In the past, for air-to-fuel (A/F) ratio control of an automobile fuel injection system, feedback control was generally performed by an O
2
sensor or a linear A/F ratio sensor (LAF sensor) as an A/F ratio sensor, and was successful in stationary-state operation (idle-state operation). However, during a transient state in which its speed is accelerating or decelerating, response-delays in the sensor causes the A/F ratio to be controlled with low precision, and thereby a target A/F ratio cannot be achieved. To correct this, depending upon mechanical change such as change of the degree of throttle opening, fuel is subjected to increasing/reducing correction. In this case, however, all the injected fuel does not flow into a cylinder but is deposited on a wall of an intake manifold pipe or an air suction valve, and some of the fuel deposit thereon evaporates and enters the cylinder, which makes it difficult to control the A/F ratio during the transient state in which the speed is accelerating or decelerating the engine is starting.
To pass a ULEV (Ultra Low Emission Vehicle) regulation in the United States of America, it is essential that the A/F ratio be controlled with high precision during the transient state at the starting of the engine, since quantity of HC (hydrocarbon) released during this state occupies about 80% of all in the test mode.
With a view to attaining the above object, a fuel deposit model is constructed and correction quantity of the fuel is found by an inverse system of this model, or as described in Japanese patent publication No. 3-235723, a neural network (NN) is made to learn nonlinearities such as the fuel deposit, to improve response characteristics during the transient state. In the NN, “units” which perform calculations are connected by a weighted “directional link” to construct the same, and the units respectively transmit their outputs through the link to perform information processing. Since the network system stores knowledge (information) in itself and operates adaptively to aims or environments, the A/F ratio could be controlled precisely during the transient state through the use of the network.
The prior art A/F ratio control device is thus constructed. In the internal combustion engine, all of the fuel injected by an injector does not flow into the cylinder but a part of it is deposited on the wall of the intake manifold pipe as described above. The quantity of the fuel deposited thereon varies intricately depending upon operating states (number of engine revolutions or load such as an intake air pressure) or environments (intake air temperature or cooling water temperature, atmospheric pressure, and the like), and the quantity of the evaporated fuel also varies depending upon the operating states or the environments. Hence, if the quantity of the fuel flowing into the cylinder is known, then it becomes possible to control the A/F ratio more precisely particularly during the transient state. However, use of the above deposit model cannot represent such a complicated system and only provides approximation. As a consequence, satisfactory A/F ratio control is not realized.
In a control system using the NN, it is possible to learn complicated behavior. To obtain a generalized estimation value, it is required that the output of the A/F ratio sensor be supplied to the NN as an input. In actuality, however, when the A/F ratio sensor is deactivated at very low temperature or just after the engine starts, it is impossible to perform correction control by the use of the NN which performs calculations on the output value of the sensor as input data, and it is therefore extremely difficult to estimate a generalized and highly precise A/F ratio.
SUMMARY OF THE INVENTION:
It is an object of the present invention to provide an air-to-fuel ratio control device which is capable of predictively estimating the quantity of injected fuel during a transient state at the starting of the engine and calculating the quantity of the injected fuel from the estimation, and thereby controlling an air-to-fuel ratio with high precision, with a neural network which does not receive the output of an air-to-fuel ratio sensor as an input.
It is another object of the present invention to provide an air-to-fuel ratio control device which is capable of constructing a neural network engine model which represents dynamic characteristics of the transient state at the starting of the engine and controlling the quantity of injected fuel based on the model so that a target (desired) air-to-fuel ratio is achieved.
It is still another object of the present invention to provide an air-to-fuel control device which is capable of reliably controlling an air-to-fuel ratio without being affected by disturbance and the like during the transient state.
Other objects and advantages of the invention will become apparent from the detailed description that follows. The detailed description and specific embodiments described are provided only for illustration since various additions and modifications within the spirit and the scope of the invention will be apparent to those skill in the art from the detailed description.
According to a first aspect of the present invention, a control device for controlling an air-to-fuel ratio when fuel is injected in an internal combustion engine, comprises: a state detecting unit for detecting parameters of operating states of the internal combustion engine; a counting unit for counting the number of times of explosion in a cylinder just after the engine starts; and a unit for estimating an air-to-fuel ratio just after the engine starts from the parameters and the number of times of explosion. Since temperature change in the cylinder is taken into account, the target A/F ratio can be estimated despite the fact that the dynamic characteristic of the A/F ratio is extremely nonlinear.
According to a second aspect of the present invention, a control device for controlling an air-to-fuel ratio when fuel is injected in an internal combustion engine, comprises: a correction parameter calculating unit for calculating a fuel correction parameter at the starting of the engine from fuel injection quantity Toutnn from which a target air-to-fuel ratio is obtained, which has been found with the use of a neuro-engine model representing a dynamic characteristic of an air-to-fuel ratio at the starting of the engine; and a fuel calculating unit for calculating fuel injection quantity at the starting of the engine, from the fuel correction parameter. Thereby, it is possible to perform A/F ratio control in which the A/F ratio at the starting of the engine matches the target A/F ratio.
According to a third aspect of the present invention, a control device for controlling an air-to-fuel ratio when fuel is injected in an internal combustion engine, comprises: a parameter calculating unit for calculating fuel deposit parameters at the starting of the engine, based on fuel injection quantity Toutnn from which a target air-to-fuel ratio is obtained, which has been found by the use of a neuro-engine model representing a dynamic characteristic of an air-to-fuel ratio at the starting of the engine and an intake manifold pipe deposit model at the starting of the engine; and a fuel calculating unit for calculating fuel injection quantity at the starting of the engine, based on the fuel deposit parameters and the intake manifold pipe deposit model. Therefore, it is possible to uniquely determine the fuel injection quantity so that the quantity of the fuel flowing into the cylinder is equal to the target quantity of fuel flowing into the cylinder (combustion resu
Ishida Akira
Kato Akira
Kitamura Toru
Kurokawa Naohiro
Takigawa Masuo
Matsushita Electric Industrial Co.
Vo Hieu T.
Wenderoth , Lind & Ponack, L.L.P.
Yuen Henry C.
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