System and method for controlling a transmission

Abstract

The present invention provides a smoother driving experience through the use of an advanced powertrain system for a vehicle. The powertrain system includes a transmission having a gear selection controller adapted to select one of a plurality of gear ratios, an electronic control unit, at least one information acquisition unit wherein the electronic control unit uses information from the information acquisition unit to determine if the vehicle is stationary and if the vehicle is on an expressway. If the electronic control unit determines the vehicle is stationary and the vehicle is on an expressway, then the electronic control unit sends a signal to the gear selection controller of the transmission to select a lower gear ratio that would normally be used to transition the vehicle from a stationary to a moving state.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a system and method for controlling a transmission in a vehicle. Specifically, the present invention relates to gear ratio selection for the transmission based on properties of specific factors determined by the system.BACKGROUND OF THE INVENTION[0002]Vehicles having an engine and a transmission with a plurality of gear ratios have been known in the art for quite some time. The transmission of the vehicle allows the engine to run at an appropriate RPM and provide various torques and speeds down to the powertrain to the wheels of the vehicle to provide forward motion of the vehicle.[0003]Also known is controlling the transmission having a plurality of gear ratios using various input criteria such as engine speed and requested acceleration from the driver, for example, through a driver input on an accelerator pedal.[0004]These transmissions to date have suffered from a common problem in that when operating the vehicle in a c...

AI Technical Summary

Benefits of technology

[0005]The present invention provides a smoother driving experience through the use of an advanced powertrain system for a vehicle. The powertrain system includes a transmission having a gear selection controller adapted to select one of a plurality of gear ratios, an electronic control unit, at least one information acquisition unit wherein the electronic control unit uses information from the information acquisition unit to determine if the vehicle is stationary and if the vehicle is on an expressway. If the electronic control unit determines the vehicle is stationary and the vehicle is on an expressway, then the electronic control unit sends a signal to the gear selection controller of the transmission to select a lower gear ratio that would normally be used to transition the vehicle from stationary to a moving state. In most transmissions, a lower gear ratio is equated with a higher gear number.

[0007]The system operates by the electronic control unit acquiring the vehicle's speed and determining if the vehicle is on an expressway. If the vehicle is stationary, i.e., if the vehicle's speed equals zero, and the vehicle is determined to be on an expressway, then the electronic control unit sends a signal to a gear selection controller of the transmission instructing the transmission to start in a lower gear ratio than would normally be used to start motion from a stop. For example, the electronic control unit would instruct the gear selection controller to start the vehicle in a second gear of the transmission instead of a first gear of the transmission when starting from a stationary position. This lower gear ratio reduces the available torque delivered to the wheels of the vehicle, thereby reducing the amount of jerk felt by the driver of the vehicle when vehicle motion is initiated.

Problems solved by technology

These transmissions to date have suffered from a common problem in that when operating the vehicle in a congested freeway or highway traffic situation, for example in a traffic jam on an expressway, a jerky start motion can be experienced by the operator of the vehicle.

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