Cruise control method and apparatus for a vehicle with a continuously variable transmission
This patent describes a cruise control method for a vehicle with a continuously variable transmission connected to an engine, wherein an actual speed of the engine and an actual speed ratio of the transmission are automatically controlled in a cruise control mode, so that an actual vehicle speed Vr coincides with a desired vehicle speed Vo, the engine having a throttle valve whose opening is automatically changed in the cruise control mode, by a throttle actuator which is operated by a negative pressure in an intake pipe of the engine, wherein the improvement comprises the steps of: determining whether the opening of the throttle valve reaches an upper limit of a control range of the throttle actuator in the cruise control mode; comparing the actual vehicle speed Vr with the desired vehicle speed Vo upon determination that the upper limit is reached; increasing a desired speed of the engine to an elevated level higher than that corresponding to the upper limit of the opening of the throttle valve so that the actual speed of the engine is increased, if a difference Vo-Vr of the actual vehicle speed Vr from the desired vehicle speed Vo is equal to or greater than a predetermined first positive value A1; and maintaining the elevated level of the desired speed of the engine, or decreasing the desired speed of the engine from the elevated level to the level corresponding to the upper limit of the throttle valve opening, when the difference Vo-Vr becomes smaller than a predetermined second positive value A2 which is smaller than the first positive value A1.
- Assignee:
- Toyota Jidoshi Kabushiki Kaisha, Toyota
- Patent Number(s):
- US 4771656
- OSTI ID:
- 6888777
- Resource Relation:
- Patent File Date: Filed date 26 Sep 1986
- Country of Publication:
- United States
- Language:
- English
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