GB2486708A

GB2486708A - Hybrid electric vehicle controller and method of controlling a hybrid electric vehicle having a plurality of starter devices

Info

Publication number: GB2486708A
Application number: GB1021839.4A
Authority: GB
Inventors: Philippa Laing
Original assignee: Land Rover UK Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2010-12-23
Filing date: 2010-12-23
Publication date: 2012-06-27
Also published as: WO2012085294A1; GB201021839D0

Abstract

A controller 140 for a hybrid electric vehicle (HEV) 100 having an engine 121 and a plurality of starter devices 121S, 123. The controller 140 being operable to determine which of the starter devices 121S, 123 is to be used to start the engine 121 responsive to an operating temperature of the vehicle 100. Preferably the controller 140 selects a first starter device when the temperature is below a first threshold value and a second starter device when the temperature is above the first threshold value. The controller 140 may select a plurality of starter devices 121S, 123 when the temperature is below a second threshold value. The starter device may be a starter motor 121S, crankshaft integrated starter generator (CISG) or a belt integrated starter generator (BISG) 123.

Description

HYBRID ELECTRIC VEHICLE CONTROLLER AND METHOD OF CONTROLLING A

HYBRID ELECTRIC VEHICLE

FIELD OF THE INVENTION

The present invention relates to a controller for a hybrid electric vehicle (HEV), a HEV and a method of controlling a HEV. In particular but not exclusively the invention relates to a controller for a parallel-type HEV, to a parallel-type HEV and to a method of controlling a parallel-type HEV during starting of an engine of the vehicle.

BACKGROUND

It is known to provide a hybrid electric vehicle (HEV) having an electric machine and an internal combustion engine (ICE) connected in parallel to a driveline of the vehicle.

The vehicle may be operated in an electric vehicle (EV) mode in which torque to the driveline is provided exclusively by the electric machine. Alternatively the vehicle may be operated in a parallel mode in which torque is provided to the driveline by the ICE and electric machine.

STATEMENT OF THE INVENTION

Aspects of the invention provide a controller, a vehicle and a method as claimed in the appended claims.

In another aspect of the invention for which protection is sought, there is provided a controller for a hybrid electric vehicle (HEV) having an engine and a plurality of starter devices, the controller being operable to determine which of the starter devices is to be used to start the engine responsive to an operating temperature of the vehicle.

Embodiments of the invention have the advantage that the optimum starting device may be chosen to start the vehicle depending on the operating temperature.

The controller may be operable to select a first starter device when the temperature is below a first threshold value and a second starter device when the temperature is above the first threshold value.

Optionally the controller is operable to select a plurality of starter devices to start the vehicle when the temperature is below a second threshold value.

The second threshold value may be less than the first threshold value.

Alternatively the second threshold value may be substantially equal to the first threshold value.

This feature has the advantage that two or more starters may be employed to start the engine, for example when the power available from a single device may be insufficient to start an engine efficiently.

In some embodiments this has the advantage that less fuel is passed through the engine before combustion occurs and the engine starts. Consequently, less fuel may be wasted.

Furthermore, an amount of undesirable hydrocarbons emitted to the atmosphere (or to which an engine after-treatment system is exposed) is reduced. This has the advantage that a negative impact of the vehicle upon the environment when initially started at low operating temperatures is reduced.

The operating temperature may be one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.

The operating temperature may be the ambient temperature of the environment in which the vehicle is operating. Optionally the operating temperature is the temperature of a component of the vehicle and the component is the second starter device.

This has the advantage that if the temperature of the second starter device is below a level at which the second starter device is available to start the engine, the first starter device may be selected to start the vehicle.

Advantageously at least one of the starter devices is an electric machine operable to provide torque assist to one or more wheels of the vehicle when the engine is on.

Thus the starter device may be used to both start the engine and to provide torque to one or more wheels to assist the engine when the engine is providing torque to one or more wheels.

Alternatively or in addition at least one of the starter devices is an electric machine operable to provide torque to one or more wheels of the vehicle to drive the vehicle when the engine is off.

Thus the starter device may be used to both start the engine and provide torque to one or more wheels in a electric vehicle (EV) mode.

The same starter device may be employed to provide torque assist and torque in EV mode.

The vehicle may comprise an electric machine in addition to the plurality of starter devices.

The electric machine may be operable to provide torque assist to one or more wheels of the vehicle when the engine is on.

Alternatively or in addition the electric machine may be operable to provide torque to one or more wheels of the vehicle to drive the vehicle when the engine is off.

In a further aspect of the invention for which protection is sought, there is provided a hybrid electric vehicle having an engine and a plurality of starter devices, the vehicle comprising a controller operable to determine which of the starter devices is to be used to start the engine responsive to an operating temperature of the vehicle.

Conveniently, the operating temperature is one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.

The operating temperature may be the temperature of a component of the vehicle and the component is the second starter device.

Advantageously the first starter device comprises one selected from amongst a crankshaft integrated starter generator (CISG), a crankshaft integrated motor generator (01MG) and a starter motor.

The second starter device may comprise a belt integrated starter generator (BISG).

Thus in the event that the temperature is below a temperature below which the BISG is unavailable to start the engine, for example due to a risk of excessive slippage of the belt of the BISG or of damage to the belt, the first starter device is employed to start the engine.

In a still further aspect of the invention for which protection is sought there is provided a method of starting an engine of a hybrid electric vehicle having a plurality of starter devices for starting the engine, the method comprising selecting one of the starter devices to start the engine responsive to an operating temperature of the vehicle.

The method may comprise the step of selecting a first starter device when the temperature is below a first threshold value and a second starter device when the temperature is above the first threshold value.

The method may comprise the step of selecting a plurality of starter devices to start the engine when the operating temperature is below a second threshold value.

Preferably the second threshold value is less than the first threshold value.

Preferably the starter device is selected responsive to the operating temperature being one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.

Preferably the method comprises the step of selecting the starter device responsive to the temperature of the second starter device.

The method preferably comprises the step of starting the engine by means of one selected from amongst a crankshaft integrated starter generator (CISG), a crankshaft integrated motor generator (01MG) and a starter motor when the temperature is below the first threshold value.

The method preferably further comprises the step of starting the engine by means of a belt integrated starter generator (BISG) when the temperature is above the first threshold value.

In a further aspect of the invention there is provided a controller for a hybrid electric vehicle (HEV) having an engine and an electric machine, the electric machine being operable to provide torque to one or more wheels of the vehicle to drive the vehicle, the vehicle having a plurality of starter devices, the controller being operable to determine which of the starter devices is to be used to start the engine responsive to an operating temperature of the vehicle.

One of the plurality of starter devices may comprise the electric machine operable to provide torque to one or more wheels of the vehicle.

Within the scope of this application it is envisaged that the various aspects, embodiments, examples, features and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings may be taken independently or in any combination thereof. Features described in connection with one embodiments are applicable to all embodiments, except where there is incompatibility of features.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which: FIGURE 1 is a schematic illustration of a hybrid electric vehicle according to an embodiment of the invention.

DETAILED DESCRIPTION

In one embodiment of the invention a hybrid electric vehicle 100 is provided having an engine 121 coupled to a belt integrated starter generator (BISG) 123. The BISG 123 may also be referred to as a belt integrated (or belt mounted) motor generator. The BISG 123 is coupled to a transmission 124 of the vehicle 100 by means of a clutch 122. The transmission 124 is in turn coupled to a driveline of the vehicle 100 thereby to drive a pair of front wheels 111, 112 and a pair of rear wheels 114, 115.

It is to be understood that other arrangements are also useful. For example the driveline of the vehicle 100 may be arranged to drive the pair of front wheels 111, 112 only or the pair of rearwheels 114, 115 only.

The BISG 123 has an electric machine 123M that is coupled to a crankshaft 121C of the engine 121 to provide torque thereto by means of a belt 123B. The BISG 123 is operable to provide torque to the crankshaft 121 S when it is required to start the engine 121 or when it is required to provide torque-assist to the driveline. By torque-assist is meant that the BISG 123 can provide additional torque to the driveline of the vehicle 100 via the transmission 124. This allows the amount of torque required to be developed by the engine 121 to be reduced. This in turn allows a reduction in fuel consumption and CO2 emissions to be enjoyed.

Furthermore in some embodiments this allows a smaller engine 121 to be used for a given amount of maximum required torque thereby allowing a smaller and more efficient engine 121 to be employed.

The vehicle 100 of FIG. 1 is configured not to operate in an electric vehicle (EV) mode in which the vehicle is powered solely by an electric motor and may therefore be referred to as a mild hybrid electric vehicle'. It is to be understood that embodiments of the invention are suitable for use with other types of hybrid electric vehicle such as full hybrid electric vehicles operable in an EV mode and a parallel mode. Some embodiments of the invention are suitable for use with full hybrid electric vehicles having an EV mode and a series mode in which the engine generates electrical power to power an electric machine to provide torque to one or more wheels of the vehicle.

In addition to the BISG 123 the engine 121 is also provided with a starter motor 121S operable to start the engine 121 when required. The starter motor 121S may be a twin solenoid starter motor (TSS). Other starter motors 121S are also useful.

In the embodiment of FIG. 1 the controller 140 is arranged to be provided with a signal responsive to an ambient temperature of the environment in which the vehicle 100 is operating. When the vehicle 100 is first started and it is required to start the engine 121, the controller 140 is arranged to determine whether the starter motor 1213 or the BISG 123 should be employed to start the engine 121. It is to be understood that it is generally preferable for the BISG 123 to be employed due to noise, vibration and harshness (NVH) considerations. This is because the NVH performance of the vehicle 100 is typically better when the BISG 123 is employed rather than the starter motor 1213.

However, the performance of the BISG 123 may be degraded in relatively cold ambient conditions. For example, a rate of wear of components of the BISG 123 may be increased as temperature falls below a given value. In addition or instead, when a BISG 123 is employed in cold ambient temperatures NVH performance may deteriorate below that which would be experienced if the starter motor 121 S were employed instead of the BISG 123. In some cases noise due to slippage of the belt of the BISG 123 in low ambient temperature conditions can be unacceptably high.

Accordingly, when the engine 121 is first started in a given drive cycle the controller 140 is arranged to select the starter motor 1213 to start the engine 121 when the ambient temperature is below a prescribed threshold level. In some embodiments the threshold level is selected to be a temperature below which NVH performance of the vehicle 100 when started with the BISG 123 is below that of the vehicle 100 when started using the starter motor 1213. Other arrangements are also useful.

In some embodiments the prescribed threshold level may be higher than that at which the NVH performance of the BISG 123 is less than that of the starter motor 1215, for example in cases where the BISG 123 has a higher minimum operating temperature specified by a manufacturer.

ln some embodiments the controller 140 is configured to determine a temperature of a portion of the BISG 123 and to employ the BISG 123 to start the engine 121 only if the temperature of the portion of the BISG 123 exceeds the prescribed threshold value.

Furthermore, the controller 140 may be configured to determine the temperature of the BISG 123 each time it is required to start the engine 121 within a given drive-cycle.

It is to be understood that if the vehicle 100 is operating in particularly cold ambient temperatures and the vehicle 100 is stationary for an extended period of time with the engine off, for example a in queuing traffic, the temperature of the BISO 123 may fall below the threshold value. Having a controller 140 that checks the temperature each time the engine 121 is to be started and selects an appropriate starter device 1215, 123 has the advantage that a risk that NVH performance is unnecessarily degraded due to ambient temperature conditions may be reduced.

Furthermore, a longevity of one or more components of the vehicle such as a starter motor 1215 or BISO 123 may also be improved. For example, in some cases a BISG 123 may suffer damage or excessive wear when operated below a prescribed temperature. This may be due at least in part to an effect of temperature on a material from which the belt 123B is made, or any other component of the BISG 123 or components with which the BISG 123 interacts.

It is to be understood that other arrangements are also useful.

Throughout the description and claims of this specification, the words comprise" and "contain" and variations of the words, for example tomprising" and tomprises", means including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

CLAIMS: 1. A controller for a hybrid electric vehicle (HEV) having an engine and a plurality of starter devices, the controller being arranged to determine which of the starter devices is to be used to start the engine in dependence on an operating temperature of the vehicle.
2. A controller as claimed in claim 1 operable to select a first starter device when the temperature is below a first threshold value and a second starter device when the temperature is above the first threshold value.
3. A controller as claimed in claim 1 or claim 2 operable to select a plurality of starter devices to start the vehicle when the temperature is below a second threshold value.
4. A controller as claimed in claim 3 depending on claim 2 wherein the second threshold value is less than the first threshold value.
5. A controller as claimed in claim 3 depending on claim 2 wherein the second threshold value is substantially equal to the first threshold value.
6. A controller as claimed in any preceding claim wherein the operating temperature is at least one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.
7. A controller as claimed in claim 6 depending through claim 2 wherein the operating temperature is the temperature of a component of the vehicle and the component is the second starter device.
8. A hybrid electric vehicle having an engine and a plurality of starter devices, the vehicle comprising a controller arranged to determine which of the starter devices is to be used to start the engine in dependence an operating temperature of the vehicle.
9. A vehicle as claimed in claim 8 operable to select a first starter device when the temperature is below a first threshold value and a second starter device when the temperature is above the first threshold value.
10. A vehicle as claimed in claim 8 or claim 9 wherein the operating temperature is one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.
11. A vehicle as claimed in claim 10 as dependent on claim 9 wherein the operating temperature is the temperature of a component of the vehicle and the component is the second starter device.
12. A vehicle as claimed in any one of claims 8 to 11 wherein at least one of the starter devices is an electric machine operable to provide torque assist to one or more wheels of the vehicle when the engine is on.
13. A vehicle as claimed in any one of claims 8 to 12 wherein at least one of the starter devices is an electric machine operable to provide torque to one or more wheels of the vehicle to drive the vehicle when the engine is off.
14. A vehicle as claimed in any one of claims 8 to 13 comprising an electric machine in addition to the plurality of starter devices.
15. A vehicle as claimed in claim 14 wherein the electric machine is operable to provide torque assist to one or more wheels of the vehicle when the engine is on.
16. A vehicle as claimed in claim 14 or 15 wherein the electric machine is operable to provide torque to one or more wheels of the vehicle to drive the vehicle when the engine is off.
17. A vehicle as claimed in claim 9 or any one of claims 10 to 16 depending through claim 9 wherein the first starter device comprises one selected from amongst a crankshaft integrated starter generator (CISG), a crankshaft integrated motor generator (01MG) and a starter motor.
18. A vehicle as claimed in claim 9 or any one of claims 10 to 17 depending through claim 9 wherein the second starter device comprises a belt integrated starter generator (BISG).
19. A method of starting an engine of a hybrid electric vehicle having a plurality of starter devices for starting the engine, the method comprising selecting one of the starter devices to start the engine in dependence on an operating temperature of the vehicle.
20. A method as claimed in claim 19 comprising the step of selecting a first starter device when the operating temperature is below a first threshold value and a second starter device when the operating temperature is above the first threshold value.
21. A method as claimed in claim 19 or claim 20 comprising the step of selecting a plurality of starter devices to start the engine when the operating temperature is below a second threshold value.
22. A method as claimed in claim 21 as dependent on claim 20 wherein the second threshold value is less than the first threshold value.
23. A method as claimed in claim 21 as dependent on claim 20 wherein the second threshold value is substantially equal to the first threshold value.
24. A method as claimed in any one of claims 19 to 23 comprising the step of selecting the starter device responsive to an operating temperature whereby the operating temperature is one selected from amongst an ambient temperature, a temperature of a component of the vehicle and a temperature of a fluid of the vehicle.
25. A method as claimed in claim 24 depending through claim 20 comprising the step of selecting the starter device responsive to the temperature of a component of the vehicle, the component being the second starter device.
26. A method as claimed in claim 20 or any one of claims 21 to 25 depending through claim 20 comprising the step of starting the engine by means of one selected from amongst a crankshaft integrated starter generator (CISG), a crankshaft integrated motor generator (01MG) and a starter motor when the temperature is below the first threshold value.
27. A method as claimed in claim 20 or any one of claims 21 to 26 depending through claim 20 comprising the step of starting the engine by means of a belt integrated starter generator (BISG) when the temperature is above the first threshold value.
28. A controller substantially as hereinbef ore described with reference to the accompanying drawings.
29. A vehicle substantially as hereinbefore described with reference to the accompanying drawings.
30. A method substantially as hereinbefore described with reference to the accompanying drawings.