Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Electric vehicle
Reexamination Certificate
2002-07-25
2003-02-04
Camby, Richard M. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Electric vehicle
C701S104000, C180S065510, C123S481000
Reexamination Certificate
active
06516254
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control device for parallel type hybrid vehicles in which the operation of a cylinder can be stopped. More specifically, the present invention relates to a control device for a hybrid vehicle which enables improvement in fuel consumption efficiency while maintaining salability when the vehicle is reaccelerated from a cylinder deactivated operation state.
2. Description of Related Art
Hybrid vehicles provided with a motor as an auxiliary driving source for running the vehicle in addition to an engine have been conventionally known. A parallel hybrid vehicle in which output from an engine is auxiliary assisted by a motor is a variation of the hybrid vehicles.
In the parallel hybrid vehicle, output from the engine is auxiliary assisted by the motor when the vehicle is accelerated, and various controls, such as charging of batteries using deceleration regeneration, are performed when the vehicle is decelerated so that the needs of the driver can be satisfied while maintaining remaining charge (electric energy) of the batteries. Also, the parallel hybrid vehicle, in terms of its structure, has a mechanism in which the engine and the motor are arranged in series. Accordingly, the parallel hybrid vehicle has advantages in that its structure can be simplified to decrease the weight thereof and to improve the degree of freedom in vehicle loading capacity.
The types of the parallel hybrid vehicle includes one in which a clutch is provided between the engine and the motor in order to eliminate the influence of engine friction (engine brake) during deceleration regeneration as disclosed in, for instance, the Japanese Unexamined Patent Application, First Publication No. 2000-97068, and one in which the engine, motor, and transmission are connected in series in order to maximally simplify its structure as disclosed in, for instance, the Japanese Unexamined Patent Application, First Publication No. 2000-125405.
However, the former in which the clutch is provided between the engine and the motor has disadvantages that its structure is complicated due to the presence of the clutch, which in turn deteriorates the loading capacity, and that its mechanical efficiency of power transmission during a running mode is decreased due to the used of the clutch. On the other hand, the latter in which the engine, motor, and transmission are connected in series has a regeneration amount decreased by the above-mentioned engine friction, and hence the amount of electric energy obtained by regeneration is reduced. Accordingly, it has problems in that the driving auxiliary (i.e., the amount of assist) etc. is restricted by the motor.
Also, in the former, a method for reducing engine friction during deceleration is available in which the amount of regeneration is increased by controlling a throttle valve to an open side during deceleration using an electronic control throttle mechanism in order to significantly decrease a pumping loss. However, there is a problem that a large amount of new gas directly flows into an exhaust system during deceleration to lower the temperature of catalyst or an A/F sensor, and exhaust gas control is adversely influenced.
With regard to the above, proposals have been made to solve the problem by using a cylinder deactivation technique. However, there is a problem in that smooth transition from a cylinder deactivated state to an all cylinder operation state is difficult.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a control device for a hybrid vehicle which enables a smooth transition from the cylinder deactivated state to the all cylinder operation state using a cylinder deactivation technique so as to improve fuel consumption efficiency.
In order to achieve the above object, the present invention provides a control device for a hybrid vehicle provided with an engine (for instance, an engine E in an embodiment described later) including a plurality of cylinders and a motor (for instance, a motor M in the embodiment described later) as driving sources, in the vehicle a supply of fuel to the engine during a deceleration state of the vehicle is stopped and a regeneration control is performed by the motor in accordance with the state of deceleration, and the engine is a cylinder deactivatable engine capable of switching to an all cylinder operation state from a cylinder deactivated operation state in which at least one of the cylinders is deactivated, and vice versa, so that a cylinder deactivated operation of the engine is carried out in accordance with an operation state of the vehicle during deceleration, the control device comprising: an actual intake gas negative pressure detection unit (for instance, an inlet pipe negative pressure sensor SI in the embodiment described later) which detects an intake air negative pressure for the engine; an estimated intake gas negative pressure calculation unit (for instance, a step S
201
shown in
FIG. 5
in the embodiment described later) which estimates an intake air negative pressure based on a revolution number of the engine and an opening degree of a throttle, both the actual intake gas negative pressure detection unit and the estimated intake gas negative pressure calculation unit being used when the operation state of the engine is switched to the all cylinder operation state from the cylinder deactivated operation state, and a supply of fuel to the engine is about to be restarted by a fuel supply amount control unit (for instance, an FIECU
11
in the embodiment described later); and an engine control unit (for instance, also the FIECU
11
in the embodiment described later) which compares an actual intake gas negative pressure obtained by the actual intake gas negative pressure detection unit with an estimated intake gas negative pressure obtained by the estimated intake gas negative pressure calculation unit, the engine control unit prohibits a fuel supply to the engine until the actual intake gas negative pressure matches the estimated intake gas negative pressure, and carries out the fuel supply to the engine when the actual intake gas negative pressure matches the estimated intake gas negative pressure.
According to the above control device for a hybrid vehicle, it becomes possible, when returning to the all cylinder operation state to the cylinder deactivated operation state, to stop the fuel supply until the actual intake gas pressure matches the estimated intake gas negative pressure, and to restart the fuel supply quickly when the actual intake gas pressure matches the estimated intake gas negative pressure. Accordingly, as compared with the case where a fuel supply is restarted when the inlet pipe negative pressure is completely recovered, it becomes possible to shorten the time interval to the fuel supply and improve the salability during reacceleration after returning from the cylinder deactivated operation state.
In accordance with another aspect of the invention, in the control device for a hybrid vehicle, an initial value of fuel injection amount smaller than a normal fuel injection amount is set when the fuel supply is restarted, and an amount of the fuel supply is gradually increased until the fuel injection amount reaches the normal fuel injection amount.
According to the above control device for a hybrid vehicle, it becomes possible to suppress the generation of shock by gradually increasing the amount of fuel supply which is started when the actual intake gas negative pressure matches the estimated intake gas negative pressure. Accordingly, the salability during reacceleration can be improved.
In accordance with yet another aspect of the invention, in the control device for a hybrid vehicle, a predetermined amount of ignition retard is carried out when returned to the all cylinder operation state from the cylinder deactivated operation state, and an ignition timing is gradually returned to a normal ignition timing after restarting a fuel injection.
According to the above control device
Kamo Tomoharu
Matsubara Atsushi
Nakamoto Yasuo
Nakaune Kan
Wakashiro Teruo
Arent Fox Kintner & Plotkin & Kahn, PLLC
Camby Richard M.
Honda Giken Kogyo Kabushiki Kaisha
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