Hybrid electric vehicle control system and method

• US 9,815,451 B2
• Filed: 12/10/2013
• Issued: 11/14/2017
• Est. Priority Date: 12/10/2012
• Status: Active Grant

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Inventors: Dextreit, Clement, Ellis, Mark, Hancock, Matt
• Primary Examiner(s): Amin, Bhavesh V
• Application Number:
  US14/650,716
• Publication Number:
  US 20150314775A1
• Time in Patent Office: 1,435 Days
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 20/12 using control strategies taking into account route information estimation or calculation of non-directly measurable driving parameters B60W40/00
• CPC Class Codes: B60W 20/19 for achieving enhanced acceleration
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2552/20 Road profile, i.e. the change in elevation or curvature of a plurality of continuous road segments
• CPC Class Codes: B60W 2552/25 Road altitude
• CPC Class Codes: B60W 2555/60 Traffic rules, e.g. speed limits or right of way
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2710/0677 Engine power
• CPC Class Codes: B60W 2710/086 Power
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 50/0097 Predicting future conditions
• CPC Class Codes: B60W 50/085 Changing the parameters of the control units, e.g. changing limit values, working points by control input
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

The invention relates to a control system for a hybrid electric vehicle (100), the vehicle having a powertrain (135) comprising at least one electric propulsion motor (123) and at least one engine (121), the control system being operable to control the vehicle to operate in an electric vehicle (EV) mode in which the at least one engine remains switched off and the at least one electric propulsion motor is configured to deliver drive torque and a boost mode in which the at least one engine is switched on to provide additional power to drive the vehicle. When the vehicle is operating in EV mode the system is further operable to determine whether a boost location exists ahead of the vehicle being a location at which a gradient of a driving surface is sufficiently high to require selection of the boost mode, the control system being operable automatically to command starting of the at least one engine before the boost location is reached.

Claims

1. A control system for a hybrid electric vehicle, the vehicle having a powertrain comprising at least one electric propulsion motor and at least one engine, the control system being configured to control the vehicle to operate in an electric vehicle (EV) mode in which the at least one engine remains switched off and the at least one electric propulsion motor is configured to deliver drive torque and in a boost mode in which the at least one engine is switched on to provide additional power to drive the vehicle,

the control system being configured to receive a target vehicle speed set by a driver and being configured to control the powertrain to maintain the target vehicle speed,

wherein the control system includes a determination module configured to, when the vehicle is operating in EV mode, determine whether a boost location exists ahead of the vehicle, wherein the boost location is a location at which a gradient of a driving surface requires selection of the boost mode in order to maintain the target vehicle speed, the control system being configured automatically to command starting of the at least one engine before the boost location is reached and wherein, when the vehicle is operating in the boost mode, the control system is configured to assume the EV mode in advance of arrival at an EV mode location if the control system determines that EV mode may be assumed without a drop in vehicle speed exceeding a prescribed value before the EV mode location is reached.

2. The control system of claim 1, wherein, in the boost mode, the additional power to drive the vehicle is power from the at least one engine that is required in addition to power provided by the at least one electric propulsion motor to drive the vehicle at a desired vehicle speed, and wherein the boost location is a location at which the gradient of the driving surface requires selection of the boost mode in order to maintain the desired vehicle speed.

3. The control system of claim 1, further configured to command starting of the at least one engine in advance of arrival at the boost location such that the at least one engine may provide the additional power at the boost location.

4. The control system of claim 1, wherein the determination module is configured to determine when to start the at least one engine in dependence on an amount of time required to start the at least one engine and an amount of time required to deliver power to drive the vehicle via the at least one engine following starting of the at least one engine.

5. The control system of claim 1, further configured to control the vehicle to operate in a parallel hybrid electric vehicle (HEV) mode in which the at least one engine delivers drive torque to drive the vehicle.

6. The control system of claim 1, further configured to control the vehicle to operate in a series HEV mode in which the at least one engine drives a generator to generate electricity to power the at least one electric propulsion motor.

7. The control system of claim 1, wherein, when the vehicle is operating in the boost mode, the control system is configured to identify an EV mode location ahead of the vehicle at which a gradient of the driving surface allows resumption of operation in EV mode whilst allowing the target speed to be maintained.

8. The control system of claim 7, wherein the determination module is further configured to determine a location of a next boost location ahead of a next EV mode location.

9. The control system of claim 8, wherein the determination module is configured to determine the time or distance between the next EV mode location and the next boost location, wherein the control system is further configured to over-ride assumption of the EV mode at the next EV mode location if a time to travel from the next EV mode location to the next boost location is less than a prescribed time or a distance between the EV mode location and the next boost location is less than a prescribed value.

10. The control system of claim 1, wherein the determination module is configured to determine at least one of a current speed of the vehicle and a current rate of acceleration of the vehicle and wherein the control system is further configured to determine whether the EV mode may be assumed in advance of arrival at the EV mode location without a drop in vehicle speed exceeding a prescribed value in further dependence on at least one selected from amongst a current speed of the vehicle and a current rate of acceleration of the vehicle.

11. The control system of claim 1, wherein the control system is operable in a first mode in which the system is configured to receive a target speed set by the driver and maintain the target speed with the at least one engine switched off and in a second mode in which the system is configured to receive a target speed set by the driver and maintain the target speed without preventing stopping and starting of the at least one engine, the control system being configured to start the at least one engine in advance of arrival at the boost location only if the control system is operated in the first mode.

12. The control system of claim 1, further comprising a location determining system, and wherein the control system is configured to receive vehicle location data from the location determining system and to determine driving surface gradient in dependence on the vehicle location data.

13. The control system of claim 12, wherein the location determining system comprises at least one of a global positioning system (GPS) receiver and a cellular network location determination system.

14. The control system of claim 12, further configured to access a database containing data corresponding to a height or altitude of the driving surface as a function of location and to calculate the gradient of the driving surface ahead of the vehicle in dependence on the height or altitude data and the vehicle location data.

15. The control system of claim 12, further configured to access a database containing data regarding driving surface gradient as a function of location, and to determine the gradient of the driving surface ahead of the vehicle in dependence on the vehicle location data.

16. The control system of claim 1, further configured automatically to command starting of the at least one engine before the boost location is reached regardless of whether or not the target vehicle speed has been set by the driver.

17. A method of controlling a hybrid electric vehicle, the vehicle having a powertrain comprising at least one electric propulsion motor and at least one engine, the method comprising the following performed by a control system of the vehicle:

controlling the powertrain to operate in an electric vehicle (EV) mode in which the at least one engine remains switched off and the at least one electric propulsion motor delivers drive torque or a boost mode in which the at least one engine is switched on to provide additional power to drive the vehicle;

receiving a target vehicle speed set by a driver;

controlling the powertrain to maintain the target vehicle speed;

determining, when the vehicle is in the EV mode, whether a boost location exists ahead of the vehicle, wherein the boost location is a location at which a gradient of a driving surface requires assumption of the boost mode in order to maintain the target vehicle speed; and

responsive to identifying the boost location, commanding automatically starting of the at least one engine before the boost location is reached; and

assuming the EV mode in advance of arrival at an EV mode location if the control system determines that EV mode may be assumed without a drop in vehicle speed exceeding a prescribed value before the EV mode location is reached.

18. The method of claim 17, wherein, in the boost mode, the additional power to drive the vehicle is power that is required in addition to power provided by the at least one electric propulsion motor to drive the vehicle at a desired vehicle speed, and wherein the boost location is a location at which the gradient of the driving surface requires assumption of the boost mode in order to maintain the desired vehicle speed.

19. The method of claim 17, further comprising, in the boost mode, controlling the powertrain to operate in a parallel recharge mode in which the engine drives a generator to recharge a battery of the vehicle and provides drive torque to drive the vehicle.

20. The method of claim 17, further comprising, in the boost mode, controlling the powertrain to operate in a parallel idle mode in which the engine provides drive torque to drive the vehicle and the at least one electric propulsion motor does not provide drive torque.

21. The method of claim 17, further comprising, in the boost mode, controlling the powertrain to operate in a parallel boost mode in which the engine and the at least one electric propulsion motor deliver drive torque to drive the vehicle.

22. A hybrid electric vehicle comprising:

a control system; and

a powertrain comprising at least one electric propulsion motor and at least one engine,

the powertrain being configured by the control system in an electric vehicle (EV) mode in which the at least one engine remains switched off and the at least one electric propulsion motor delivers drive torque, and a boost mode in which the at least one engine is switched on to provide additional power to drive the vehicle,

the control system being configured to allow a driver to set a target vehicle speed and being configured to control the powertrain to maintain the target vehicle speed,

wherein, when in the boost mode, the control system determines whether an EV mode location exists ahead of the vehicle at which a gradient of a driving surface allows assumption of the EV mode whilst maintaining the target vehicle speed to within a prescribed amount, the control system being configured to allow assumption of the EV mode before the EV mode location is reached responsive to a determination that a drop in vehicle speed before reaching the EV mode location will not exceed a prescribed amount.