Control unit for hybrid vehicle

• US 8,831,811 B2
• Filed: 03/31/2011
• Issued: 09/09/2014
• Est. Priority Date: 04/05/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Yamazaki, Yuichiro
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Payne, Robert
• Application Number:
  US13/634,842
• Publication Number:
  US 20130018540A1
• Time in Patent Office: 1,258 Days
• Field of Search: 701/22, 701/71, 701/69, 701/54, 180/65.245, 180/65.21, 180/65.285, 180/233, 180/65.28, 180/65.275, 180/65.26, 180/65.1, 180/165, 903/930, 903/903, 903/905
• US Class Current: 701/22
• CPC Class Codes: B60K 6/448 Electrical distribution type
• CPC Class Codes: B60K 6/46 Series 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 10/26 for electrical energy, e.g. batteries or capacitors
• 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 20/12 using control strategies taking into account route information estimation or calculation of non-directly measurable driving parameters B60W40/00
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 20/17 for noise reduction
• CPC Class Codes: B60W 2510/085 Power
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/0677 Engine power
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: B60W 40/076 Slope angle of the road
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A control unit for a series hybrid vehicle includes a basic required output calculator for calculating a basic required output for driving the vehicle based on a vehicle speed and an accelerator pedal opening, a gradient calculator for calculating a rising gradient of a road surface on which the vehicle runs, a correction output calculator for calculating a correction output which is added to the basic required torque based on the rising gradient, and a target output calculator for calculating, when a required output which results from adding the correction output to the basic required output is larger than a predetermined value, based on the required output, a battery target electric power by which the battery is required to output part of the required output and an engine target output by which the engine is required to output the remaining of the required output.

Claims

1. A control unit for a hybrid vehicle, the hybrid vehicle including:

an engine;

a generator which generates electric power by being driven by the engine;

a battery which supplies electric power to an electric motor; and

the electric motor which is connected to a drive shaft of the hybrid vehicle and which is driven by means of electric power supplied from at least either of the battery and the generator,

wherein the control unit includes;

a basic required output calculator for calculating a basic required output for driving the hybrid vehicle based on a driving speed of the hybrid vehicle and an accelerator pedal opening which corresponds to an accelerator pedal operation in the hybrid vehicle;

a gradient calculator for calculating a rising gradient of a road surface on which the hybrid vehicle runs;

a correction output calculator for calculating a correction output which is added to the basic required torque based on the rising gradient; and

a target output calculator for calculating, when a required output which results from adding the correction output to the basic required output is larger than a predetermined value, based on the required output, a battery target electric power by which the battery is required to output part of the required output and an engine target output by which the engine is required to output the remaining of the required output.

2. The control unit of claim 1,

wherein the target output calculator has:

a basic battery target electric power calculator for calculating a basic battery target electric power for the battery based on the basic required output;

a basic engine target output calculator for calculating a basic engine target output for the engine; and

a correction value calculator for calculating a battery target electric power correction value which is added to the basic battery target electric power and an engine target output correction value which is added to the basic engine target output,

wherein the battery target electric power is calculated by adding the battery target electric power correction value to the basic battery target electric power, and

wherein the engine target output is calculated by adding the engine target output correction value to the basic engine target output.

3. The control unit of claim 2,

wherein the correction value calculator has a covering rate setting module for setting a covering rate of the correction output by the battery based on the basic engine target output, calculates the battery target electric power correction value based on the correction output and the covering rate, and calculates the engine target output correction value based on the correction output and the battery target electric power correction value.

4. The control unit of claim 3,

wherein the engine is driven so as to trace a high efficient fuel consumption line, and

wherein the covering rate setting module sets the covering rate of the correction output by the battery so that the basic engine target output becomes smaller when the basic engine target output is smaller than a predetermined engine output which is smaller than a maximum efficiency output at which the engine operates with a maximum efficiency than when the basic engine target output is the maximum efficiency output or larger.

5. The control unit of claim 4,

wherein the covering rate setting module sets the covering rate of the correction output by the battery so that the basic engine target output increases from the predetermined engine output towards the maximum efficiency output when the engine target output is equal to or larger than the predetermined engine output and smaller than the maximum efficiency output.

6. The control unit of claim 3, further including:

a state-of-charge obtaining module for obtaining a state-of-charge of the battery,

wherein, when the state-of-charge is a predetermined value or smaller and the correction output is smaller than a predetermined correction output, the covering rate setting module sets the covering rate of the correction output by the battery so that the battery does not cover the correction output at all.

7. The control unit of claim 3, further including:

a state-of-charge obtaining module for obtaining a state-of-charge of the battery,

wherein, when the state-of-charge is a predetermined value or larger, the covering rate setting module sets the covering rate of the correction output by the battery so that the battery covers the correction output in whole.

8. The control unit claim 3, further including:

a state-of-charge obtaining module for obtaining a state-of-charge of the battery,

wherein, when the state-of-charge is a predetermined value or smaller and the correction output is larger than a predetermined correction output, the correction output calculator limits the correction output to the predetermined correction output, and

wherein the covering rate setting module sets the covering rate of the correction output by the battery so that the battery does not cover the correction output at all.

9. The control unit of claim 7,

wherein, when the state-of-charge is a predetermined value or larger, the covering rate setting module sets the covering rate of the correction output by the battery so that the battery covers the correction output in whole.

10. The control unit of claim 8,

wherein, when the state-of-charge is a predetermined value or larger, the covering rate setting module sets the covering rate of the correction output by the battery so that the battery covers the correction output in whole.