US 2021/0316731 A1Published application

Directional shift control in vehicles

AssigneeCaterpillar Inc.

InventorsRobert Nicholas HARPER, Abhishek AWANA, Christopher L. WYNKOOP, Mariappan PARAMASIVAN

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Abstract

The present disclosure relates to a method of controlling gear selection in a transmission of a vehicle in response to a directional shift requested by an operator and to a control system for controlling gear selection to manage directional shifts in vehicles, from a first direct to a second direction (e.g. forward to reverse). The method compares the current transmission output speed with a predetermined direction shift threshold transmission output speed. If the current transmission output speed is less than or equal to the predetermined direction shift threshold transmission output speed, the transmission is caused to execute a direction shift from the initial first direction gear to the same second direction gear, or a next highest second direction gear if there is no second direction gear which corresponds to the initial first direction gear. If the current transmission output speed is greater than the predetermined direction shift threshold transmission output speed, the direction shift is inhibited until the current transmission output speed slows to less than or equal to the predetermined direction shift threshold transmission output speed.

Claims9

Dependent claims

A method of controlling gear selection in a transmission of a vehicle, said vehicle having a power unit and an automatic transmission, said transmission having a plurality of first direction gears configured to move the vehicle in a first direction and a plurality of second direction gears configured to move the vehicle in a second direction which is opposite to the first direction, the method comprising the steps of:

determining a direction shift request by a vehicle operator to move the vehicle from the first to the second direction when the transmission is in an initial first direction gear;
determining a current transmission output speed;
comparing the current transmission output speed with a predetermined direction shift threshold transmission output speed;
and
if the current transmission output speed is less than or equal to the predetermined direction shift threshold transmission output speed, causing the transmission to execute a direction shift from the initial first direction gear to the same second direction gear, or a next highest second direction gear if there is no second direction gear which corresponds to the initial first direction gear, and
if the current transmission output speed is greater than the predetermined direction shift threshold transmission output speed, inhibiting the direction shift until the current transmission output speed slows to less than or equal to the predetermined direction shift threshold transmission output speed.

3 more elements

A control system for controlling gear selection in a transmission of a vehicle, said vehicle having a power unit and an indirect drive automatic transmission, said transmission having a plurality of first direction gears configured to move the vehicle in a first direction and a plurality of second direction gears configured to move the vehicle in a second direction which is opposite to the first direction, said control system configured to;

evaluate direction control signals to determine when a direction shift request is made by a vehicle operator to move the vehicle from the first to the second direction when the transmission is in an initial first direction gear;
determine a current transmission output speed;
compare the current transmission output speed with a predetermined direction shift threshold transmission output speed;
and
if the current transmission output speed is less than or equal to the predetermined direction shift threshold transmission output speed, generate a transmission direction shift signal to cause the transmission to execute a direction shift from the initial first direction gear to the same second direction gear, or a next highest second direction gear if there is no second direction gear which corresponds to the initial first direction gear, and
if the current transmission output speed is greater than the predetermined direction shift threshold transmission output speed, inhibit the direction shift until the current transmission output speed slows to less than or equal to the predetermined direction shift threshold transmission output speed.

3 more elements

Dependencies are inferred from the claim text.