Vehicle control system

#The present invention claims the benefit of priority to Japanese Patent Application No. 2015-088039 filed on Apr. 23, 2015 with the Japanese Patent Office, the entire contents of which are incorporated herein by reference in its entirety.

#Field of the Invention

#Embodiments of the present invention relates to the art of a control system for a vehicle having a continuously variable transmission, and especially to a vehicle control system configured to control speed ratio and driving force during downshifting of the continuously variable transmission.

#Features, aspects, and advantages of exemplary embodiments of the present invention will become better understood with reference to the following description and accompanying drawings, which should not limit the invention in any way.

#FIG. 1 is a schematic illustration showing the control system of the vehicle to which the vehicle control system according to the preferred embodiment is applied;

#FIG. 2 is a flowchart showing a control example carried out by the vehicle control system according to the preferred embodiment;

#Hereinafter, preferred embodiment of the present application will be explained with reference to the accompanying drawings. The vehicle control system according to the preferred embodiment is applied to a vehicle having an automatic transmission such as a continuously variable transmission adapted to deliver an engine power to driving wheels while changing a speed. For example, a belt-driven continuously variable transmission and a toroidal continuously variable transmission adapted to change a speed ratio continuously can be used in the vehicle to which the vehicle control system is applied. The vehicle control system may also be applied to a hybrid vehicle having a power distribution device for distributing and synthesizing powers of an engine and a motor such as an electric continuously variable transmission.

#Referring now to FIG. 1, there is shown a structure and a control system of a vehicle Ve to which the vehicle control system according to the preferred embodiment is applied. The vehicle Ve shown in FIG. 1 is a rear-wheel-drive vehicle comprising a pair of front wheels 1 and a pair of rear wheels 2. In the vehicle Ve, power of an engine (referred to as “ENG” in FIG. 1) 3 is delivered to the rear wheels 2 through a continuously variable transmission (referred to as “CVT” in FIG. 1) 4 and a differential gear unit 5. Here, it is to be noted that the vehicle control system may also be applied to a front-wheel-drive vehicle in which power of the engine 3 is delivered to the front wheels 1, and to a four-wheel-drive vehicle in which power of the engine 3 is delivered to both front wheels 1 and rear wheels 2.

#Although not shown in FIG. 1, the engine 3 is provided with an electric throttle valve, an electric fuel injection device, an airflow sensor for detecting an air intake and so on. According to the preferred embodiment, therefore, an output power of the engine 3 may be controlled automatically by electrically controlling the electric throttle valve based on detection data of the airflow sensor.