Motor vehicles – With means responsive to speed of vehicle for maintaining... – Including electrically actuated servomechanism
Reexamination Certificate
1998-08-04
2001-03-20
Mar, Michael (Department: 3619)
Motor vehicles
With means responsive to speed of vehicle for maintaining...
Including electrically actuated servomechanism
C074S003000, C701S093000
Reexamination Certificate
active
06202780
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cruise control system for a motor vehicle, which performs a constant-speed cruise control of the motor vehicle.
BACKGROUND OF THE INVENTION
With an increasing demand for making it easy and automated to operate a driving apparatus, such as an automotive vehicle, a transmission system has been automated, and a constant-speed cruise control system for enabling the driving apparatus to travel at a constant speed has been developed.
In general, the cruise control system performs constant-speed cruise control by setting a target vehicle speed to a vehicle speed detected at the time when a cruise control set switch is turned on, and controlling the vehicle so as to maintain the target vehicle speed.
Since a gear position or shift position of the transmission needs to be changed in some cases so as to keep the vehicle running at a constant speed, the cruise control system is required not only to control the engine output, but also control changes of the gear position of the transmission. To this end, the cruise control system is provided with an automatic shift device for changing the gear position to the one suitable for the current vehicle running condition, so as to maintain the target vehicle speed.
The cruise control device, as described above, is also adapted to cancel constant-speed cruise control when the driver steps on a footbrake or brake pedal, for example
In the conventional cruise control system, as described above, however, the constant-speed cruise control is not canceled when the driver selects a manual shift mode, and manually carry out a shifting operation. For example, the vehicle speed preset for the cruise control is undesirably maintained even where the driver manipulates a change lever so as to shift down the transmission so that the vehicle speed is reduced due to an effect of an engine brake.
In view of the above problem, Japanese laid-open Patent Publication No. 8-193656 discloses a technique for ignoring a shift command from a cruise control ECU when the manual shift mode is selected in an automatic transmission equipped with a manual shifting function. the manual shift mode is selected, however, only the shift command generated under the cruise control is ignored, and constant-speed cruise control is still continued or maintained, and therefore the vehicle speed cannot be reduced unless the brake pedal is depressed by the driver so that the cruise control is canceled.
Namely, if the constant-speed cruise control is kept effective even after the manual shift mode is selected and a shift command for upshifting or downshifting is generated, the vehicle speed preset for the cruise control is maintained even where the driver attempts to reduce the vehicle speed only by use of the engine brake, by shifting down the transmission without using the brake pedal. In this case, the vehicle speed cannot be reduced as desired.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a cruise control system for a motor vehicle, wherein the vehicle speed can be reduced due to an effect of an engine brake which results from a shifting operation of an automatic transmission, even while the vehicle is running under constant-speed cruise control.
To accomplish the above object, the present invention provides a cruise control system for a motor vehicle, which includes: shift manipulating means for establishing a selected one of an automatic shift mode in which an optimum gear position of an automatic transmission is automatically set according to a running condition of the vehicle, and a manual shift mode in which a gear position of the automatic transmission is allowed to be changed according to a shift command operation of a driver; shift control means for changing the gear position of the automatic transmission based on an operated state of the shifting means; target speed setting means for setting a target speed to which a vehicle speed is controlled under cruise control; actual vehicle speed detecting means for detecting an actual vehicle speed of the motor vehicle; constant-speed cruise control means for controlling an engine of the vehicle so that the actual vehicle speed detected by the actual vehicle speed setting means becomes equal to the target vehicle speed set by the target vehicle speed setting means; and canceling means for canceling an operation of the constant-speed cruise control means when the shift manipulating means is operated to switch from the automatic shift mode to the manual shift mode, and the shift command operation is performed by the driver, while the vehicle is running under constant-speed cruise control.
The present invention also provide a cruise control system for a motor vehicle, comprising:
an automatic transmission including a shift manipulating device having an automatic shift position and a manual shift position, and a shift control device which places the automatic transmission in an optimum gear position when the shift manipulating device is operated to the automatic shift position, the optimum gear position being selected from a plurality of gear positions, according to an operated state of an accelerator pedal by a driver and a running condition of the vehicle, the shift control device placing the automatic transmission in a desired gear position according to a shift command operation by a driver when the shift manipulating device is operated to the manual shift position; a target speed setting device which sets a target speed to which a vehicle speed is controlled under constant-speed cruise control; a vehicle speed sensor which detects a vehicle speed of the motor vehicle; a constant-speed cruise control device which controls an engine of the vehicle so that the vehicle speed detected by the vehicle sensor becomes equal to the target vehicle speed set by the target vehicle speed setting device; and a canceling device which cancels an operation of the constant-speed cruise control device means when the shift manipulating device is operated from the automatic shift position to the manual shift position, and the transmission is shifted to another gear position, while the vehicle is running under constant-speed cruise control performed by the constant-speed cruise control means.
REFERENCES:
patent: 4933859 (1990-06-01), Tsuyama et al.
patent: 5038880 (1991-08-01), Matsuoka et al.
patent: 5285865 (1994-02-01), Sakita
patent: 5544056 (1996-08-01), Seireg et al.
patent: 5680309 (1997-10-01), Rauznitz et al.
patent: 5758306 (1998-05-01), Nakamura
patent: 5799262 (1998-08-01), Suzuki
patent: 8-193656A (1996-07-01), None
Otani Masatoshi
Tanaka Hiroyuki
Tateno Toshiaki
Mar Michael
Mitsubishi Jidosha Kogyo Kabushiki Kaisha
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