System and method for controlling a motor vehicle with independent rear electric machines

Patent metadata

Field	Value
Publication number	US-9630522-B2
Application number	US-201314647267-A
Country	US
Kind code	B2
Filing date	Nov 26, 2013
Priority date	Nov 26, 2012
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A method controls a motor vehicle including an internal combustion engine coupled to a first axle set and to at least two electric machines each one coupled to one wheel of a second axle set. The method includes determining the speed of at least one of the electric machines; comparing the determined speed against a threshold; and altering, if the determined speed is above the threshold, the maximum torque of the electric machines so as to limit the rotational speed of the machines.

First claim

The invention claimed is:

1. A method for controlling a motor vehicle comprising an internal combustion engine coupled to a first axle set and having at least two electric machines each coupled to one wheel of a second axle set, the method comprising:
determining the speed of at least one of the electric machines;
comparing the determined speed against a threshold; and
altering, if the determined speed is above said threshold, the maximum torque of the electric machines so as to limit the rotational speed of said machines.

2. The control method as claimed in claim 1 , in which the speed of the electric machines is determined from the maximum value of the rotational speeds of left and right electric machines over a predetermined period of time.

3. The control method as claimed in claim 2 , in which the speed of the electric machines is determined from measurements of the rotational speeds of the left and right wheels of the second axle set and from the maximum value of the rotational speeds of left and right wheels over a predetermined period of time.

4. The control method as claimed in claim 1 , further comprising:
determining whether the rotational speed of the electric machines is above a first speed threshold,
if the rotational speed of the electric machines is above the first speed threshold, the maximum torque of the electric machines is regulated in order to limit their rotational speed, and,
if the rotational speed of the electric machines is above a second speed threshold higher than the first threshold, a zero maximum torque instruction is issued to the electric machines.

5. The control method as claimed in claim 1 , in which the first axle set is the front axle set, the second axle set being the rear axle set.

6. A system for controlling a motor vehicle comprising an internal combustion engine coupled to a first axle set and at least two electric machines each coupled to one wheel of the second axle set, the control system being connected to the internal combustion engine and to the electric machines, the system comprising:
a means of determining the speed of the electric machines,
a means of determining the conditions for activating a limitation of the rotational speed of the electric machines, and
a means of regulating the torque of the electric machines.

7. The control system as claimed in claim 6 , in which
the control system is connected to the electric machines by a first data link,
the means of determining the speed of the electric machines being able to determine a limit speed of the electric machines equal to the maximum value of the rotational speeds of left and right electric machines which are transmitted by the first data link over a predetermined period of time.

8. The control system as claimed in claim 6 , in which
the control system is connected to a means of controlling a braking system of the vehicle by a second data link,
the means of determining the speed of the electric machines comprising a means of recalculating the speeds of the electric machines which is able to recalculate the speed of each of the electric machines from the measurements of the rotational speeds of the right and left wheels of the second axle set which are transmitted by the second data link, if the rotational speeds of the electric machines are not transmitted by the first data link.

9. The control system as claimed in claim 6 , in which the means of determining the conditions for activating the limitation of speed comprises a non-transitory means for a memory-storage of a first speed threshold and a non-transitory means for the memory-storage of a second speed threshold higher than the first threshold.

10. The control system as claimed in claim 9 , comprising a first comparator comparing the speed of the electric machines to the first speed threshold and a means of regulating the maximum torque of the electric machines on the basis of the signal from the first comparator comparing the speeds of the electric machines.

11. The control system as claimed in claim 9 , comprising a second comparator comparing the speed of the electric machines to the second speed threshold and a means for imposing a zero maximum torque instruction on the electric machines on the basis of the signal from the second comparator.

Assignees

• Renault Sas

Inventors

• Ketfi-Cherif Ahmed
• Launay Gregory
• Maloum Abdelmalek
• Scheffges Olivier
• Debert Maxime

Classifications

• B60K2007/0092

  the motor axle being coaxial to the wheel axle · CPC title

• B60W2520/26

  Wheel slip · CPC title

• B60K17/356

  having fluid or electric motor, for driving one or more wheels · CPC title

• B60W30/18172

  Preventing, or responsive to skidding of wheels · CPC title

• B60W2510/081

  Speed · CPC title