Method for longitudinal control of a vehicle

Patent metadata

Field	Value
Publication number	US-10196062-B2
Application number	US-201715488197-A
Country	US
Kind code	B2
Filing date	Apr 14, 2017
Priority date	Apr 15, 2016
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A method for stopping of a motor vehicle including providing a creep torque via a drive train of the motor vehicle and then increasing, independently of the driver, engine speed of a drive engine of the drive train to increase a drive torque of the drive engine and simultaneously increasing, independently of the driver, a braking torque of a brake system of the motor vehicle to balance the drive torque and the braking torque of the motor wherein the maximum braking torque is as great as the creep torque during a standstill of the motor vehicle. The method then maintains the braking torque and simultaneously reduces the engine speed of the drive engine to point at which the motor vehicle comes to a standstill. In an alternative embodiment the method includes applying, independently of the driver, a braking torque by a brake system of the motor vehicle, wherein the applied braking torque is as great as the creep torque present when the motor vehicle is at a standstill and then maintaining the braking torque and simultaneously reducing the creep torque of the drive train up to a point at which the motor vehicle comes to a standstill.

First claim

What is claimed is:

1. A method for stopping a motor vehicle including:
determining if the motor vehicle speed is below a speed threshold value;
using a drive train to provide a creep torque;
increasing, independently of a driver, engine speed of the drive train to increase a drive torque to an amount above the creep torque and simultaneously increasing, independently of the driver, a braking torque of a brake system of the motor vehicle to achieve a balance between the drive torque and the braking torque of the motor vehicle wherein a maximum braking torque is as great as the creep torque during a standstill of the motor vehicle; and
maintaining the maximum braking torque and simultaneously reducing the engine speed of the drive engine to point at which the motor vehicle comes to the standstill.

2. The method of claim 1 wherein the creep torque is generated by a converter of an automatic transmission driven by the drive engine of the motor vehicle.

3. The method of claim 1 wherein the creep torque is generated by a double-clutch transmission of the motor vehicle; and
the creep torque is reduced with a clutch of the double-clutch transmission by partially disengaging said clutch of said double-clutch transmission.

4. The method of claim 1 wherein the driver-independent braking torque is braking torque applied by a service brake or a parking brake of the motor vehicle.

5. The method of claim 1 wherein the step of reducing the engine speed occurs over a time period of 3 seconds to 5 seconds.

6. The method of claim 1 wherein the speed of the drive engine is reduced more rapidly in a range in which the drive torque of the drive engine essentially reaches the braking torque applied by the brake system than in a range in which the drive torque is greater than the braking torque.

7. The method of claim 1 wherein the step of reducing the engine speed occurs only in a speed range that does not include a resonant frequency of a vehicle body.

8. The method of claim 1 wherein the creep torque is reduced or completely eliminated after the vehicle has come to the standstill.

9. The method of claim 1 wherein a stopping operation occurs when a longitudinal speed of the motor vehicle is below the speed threshold value.

10. The method of claim 9 wherein the speed threshold value lies in a range of 0 km/h to 2 km/h.

11. A method for stopping a motor vehicle including:
determining if the motor vehicle speed is below a speed threshold value;
using a drive train to provide a creep torque;
increasing independently of a driver, engine speed of the drive train to increase a drive torque to an amount above the creep torque and;
applying, independently of the driver, a braking torque by a brake system of the motor vehicle, wherein the applied braking torque is as great as the creep torque present when the motor vehicle is at a standstill; and
maintaining the braking torque and simultaneously reducing the creep torque of the drive train up to point at which the motor vehicle comes to the standstill.

12. The method of claim 11 wherein the creep torque is reduced or completely eliminated after the vehicle has come to the standstill.

13. The method of claim 11 wherein a stopping operation occurs when a longitudinal speed of the motor vehicle is below the speed threshold value.

14. The method of claim 11 wherein the speed threshold value lies in a range of 0 km/h to 2 km/h.

Assignees

• Ford Global Tech Llc

Inventors

• Das Ashrit
• Svensson Thomas

Classifications

• B60W30/18109

  Braking · CPC title

• B60W10/06

  including control of combustion engines · CPC title

• B60W30/18063

  Creeping · CPC title

• B60W2710/027

  Clutch torque · CPC title

• B60W2520/10

  Longitudinal speed · CPC title