Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
2003-04-28
2004-12-14
Wolfe, Willis R. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C123S295000, C123S299000, C123S305000, C701S104000, C701S111000, C477S107000
Reexamination Certificate
active
06832150
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. 2002-155656 filed on May 29, 2002, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to method and apparatus for controlling a diesel engine, in which an injected fuel quantity reduction process for preventing black smoke is executed based on the engine speed, and an injected fuel quantity reduction process for preventing shift shock during shifting of an automatic transmission is executed.
2. Description of Related Art
There is known a process in which a shift control system of a diesel engine causes an engine control system to reduce the injected fuel quantity during shifting so as to temporarily reduce the engine output torque, thereby avoiding or suppressing shift shock in the automatic transmission, as disclosed in Japanese Laid-open Patent Publication No. 5-71385, for example.
In the meantime, when the engine speed of the diesel engine suddenly increases, black smoke may be generated due to unstable combustion in the diesel engine. In view of this problem, the engine control system is adapted to temporarily reduce the injected fuel quantity so as to suppress or limit black smoke when the engine speed increases at a greater rate than a threshold value provided for preventing black smoke.
In the combination of the shift control system and the engine control system as described above, however, the following problem may occur: when the shift control system executes a shifting process, in particular, when the shift control system performs power-on downshifting, the engine speed suddenly increases, which may cause the engine control system to perform the injected fuel quantity reduction process for preventing black smoke as described above.
As described above, the shift control system operates to reduce the output torque of the diesel engine for preventing shift shock, and also perform switching of the combination of rotary members to be engaged or connected within the automatic transmission at a suitable point of time selected in accordance with the reduction of the engine output torque. Thus, the shift control system performs a series of these operations, thereby to prevent or reduce torque variations at the output shaft of the automatic transmission during shifting.
However, if the injected fuel quantity is reduced during shifting for the purpose of preventing black smoke, independently of shift control, the engine output torque may be reduced to such an extent that is not expected by the shift control system. In this case, the shift control system is not able to expect rotating conditions of the respective rotary elements within the automatic transmission, and cannot perform switching of the combination of the rotary members to be engaged in the transmission at a suitable point of time or in suitable timing. In this situation, the shift control system may not be able to desirably prevent torque variations at the output shaft of the automatic transmission.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide method and apparatus for controlling a diesel engine that is arranged to perform an injected fuel quantity reduction process for preventing black smoke and an injected fuel quantity reduction process for preventing shift shock, wherein the effect of preventing shift shock is not influenced or disturbed by the injected fuel quantity reduction process for black smoke prevention.
To accomplish the above object, there is provided according to a first aspect of the invention a method of controlling a diesel engine that performs an injected fuel quantity reduction process for preventing black smoke based on an engine speed, and performs an injected fuel quantity reduction process for preventing shift shock during shifting of an automatic transmission, which method comprises the step of inhibiting the injected fuel quantity reduction process for preventing black smoke during shifting of the automatic transmission.
With the method as described above, the injected fuel quantity reduction process for preventing black smoke is inhibited during shifting of the automatic transmission, and therefore reduction of the engine output torque, which is not expected by a shift control system, does not occur during shifting. Accordingly, when the automatic transmission is shifted up or down by switching the combination of rotary members to be engaged in the transmission at a suitable point of time that is determined in accordance with the injected fuel quantity reduction process for preventing shift shock, shift shock can be surely avoided or suppressed since the rotary members in the transmission are placed in rotating conditions expected by the shift control system. Thus, in the diesel engine that is arranged to perform the injected fuel quantity process for preventing black smoke and perform the injected fuel quantity process for preventing shift shock of the automatic transmission, the effect of preventing shift shock is not affected by the injected fuel quantity process for preventing black smoke.
Since the injected fuel quantity reduction process for preventing black smoke is inhibited temporarily, namely, only during shifting, the inhibition has a little influence on the effect of black smoke prevention. Furthermore, since the injected fuel quantity reduction process for preventing shift shock is performed during shifting, black smoke is likely to be suppressed even if the injected fuel quantity reduction process for preventing black smoke is inhibited, thus causing almost no problem associated with black smoke prevention.
According to a second aspect of the invention, there is provided a method of controlling a diesel engine that performs an injected fuel quantity reduction process for preventing black smoke based on an engine speed, and performs an injected fuel quantity reduction process for preventing shift shock during shifting of an automatic transmission, which method comprises the step of reducing an amount of reduction of an injected fuel quantity in the injected fuel quantity reduction process for preventing black smoke during shifting of the automatic transmission.
Instead of inhibiting the injected fuel quantity reduction process for preventing black smoke, the amount of reduction of the injected fuel quantity for preventing black smoke may be reduced during shifting of the automatic transmission. With this arrangement, even if the injected fuel quantity reduction process for preventing black smoke is executed during shifting, reduction of the engine output torque, which is not expected by the shift control system, is less likely to occur during shifting. Accordingly, when the automatic transmission is shifted up or down by switching the combination of rotary members to be engaged in the transmission at a suitable point of time that is determined in accordance with the injected fuel quantity reduction process for preventing shift shock, shift shock can be surely avoided or suppressed since the rotary members in the transmission are substantially placed in rotating conditions expected by the shift control system. Thus, in the diesel engine that is arranged to perform the injected fuel quantity process for preventing black smoke and perform the injected fuel quantity process for preventing shift shock of the automatic transmission, the effect of preventing shift shock is not affected by the injected fuel quantity process for preventing black smoke.
The amount of reduction of the injected fuel quantity for preventing black smoke is corrected to be reduced temporarily, namely, only during shifting, and the injected fuel quantity reduction process for preventing black smoke is not completely inhibited. Thus, since the injected fuel quantity may be reduced for preventing black smoke though a degree of the reduction is less than normal, the reducing correction has little influence on the effect of preventing black smoke. Furthermore, the injected fu
Higashiyama Yasuhiko
Kaigawa Masato
Hoang Johnny H.
Kenyon & Kenyon
Toyota Jidosha & Kabushiki Kaisha
Wolfe Willis R.
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