Vehicle creep torque control

Patent metadata

Field	Value
Publication number	US-9248758-B2
Application number	US-201114357799-A
Country	US
Kind code	B2
Filing date	Nov 14, 2011
Priority date	Nov 14, 2011
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Creep control is performed, in response to an accelerator-off operation, to control a second motor to cause a predetermined creep torque Tcr to be output from the second motor to a driveshaft. First creep cut-off control is performed, in response to a brake-on operation during the creep control, to control the second motor to cause a torque reduced from the creep torque Tcr at a high rate by a predetermined high variation ΔThi to be output from the second motor to the driveshaft. Subsequent to the first creep cut-off control, second creep cut-off control is performed to control the second motor to cause a torque reduced at a low rate by a predetermined low variation ΔTlow smaller than the predetermined high variation ΔThi to be output from the second motor to the driveshaft.

First claim

The invention claimed is:

1. A vehicle comprising:
a motor that is capable of supplying a torque to a driveshaft and linked with the driveshaft;
a battery that is capable of supplying electric power to the motor;
a braking force application system that applies a braking force to the vehicle in response to a braking operation; and
a controller programmed to perform a creep control that controls the motor to set the torque supplied to the driveshaft at a predetermined creep torque, in response to an accelerator-off operation, wherein
in response to a brake-on operation during the creep control, the controller is further programmed to perform a first creep cut-off control that controls the motor to reduce the torque from the predetermined creep torque at a first rate of change with time, and
subsequent to the first creep cut-off control, the controller is further programmed to perform a second creep cut-off control that controls the motor to reduce the torque at a second rate of change with time, the second rate of change with time being smaller than the first rate of change with time.

2. The vehicle according to claim 1 , wherein
the controller is programmed to start the second creep cut-off control when the torque supplied by the motor is reduced to or below a predetermined torque reference value during the first creep cut-off control, the predetermined torque reference value being smaller than the predetermined creep torque.

3. The vehicle according to claim 1 , wherein
the controller is programmed to start the second creep cut-off control when a vehicle speed is reduced to or below a predetermined vehicle speed reference value during the first creep cut-off control.

4. The vehicle according to claim 1 , wherein
the controller is programmed to perform the second creep cut-off control such that the motor reduces the torque to zero at the second rate of change with time.

5. The vehicle according to claim 1 , further comprising:
an internal combustion engine;
a generator that is capable of transmitting electric power to and from the battery and capable of inputting and outputting power; and
a planetary gear mechanism having three rotation elements connected with three shafts, the driveshaft, an output shaft of the internal combustion engine and a rotating shaft of the generator, wherein
the rotating shaft of the generator is connected with the driveshaft.

Assignees

• Yamazaki Masakazu
• Toyota Motor Co Ltd

Inventors

• Yamazaki Masakazu

Classifications

• B60L2250/26

  by pedal actuation · CPC title

• B60L2240/423

  Torque · CPC title

• B60L2240/12

  Speed · CPC title

• B60W2710/083

  Torque · CPC title

• B60W2540/10

  Accelerator pedal position · CPC title