Catalyst temperature control apparatus for hybrid vehicle

• US 6,032,753 A
• Filed: 06/02/1997
• Issued: 03/07/2000
• Est. Priority Date: 06/10/1996
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ohtsuka, Kaoru, Yamazaki, Suehiro, Izutani, Takahide
• Primary Examiner(s): Denion, Thomas E.
• Application Number:
  US08/867,069
• Time in Patent Office: 1,009 Days
• Field of Search: 60/284, 60/285, 60/286, 60/300, 60/303, 180/65.2, 180/65.3, 180/65.4, 180/309
• US Class Current: 180/65.235
• CPC Class Codes: B60K 6/24 characterised by the combustion engines
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 2270/12 of exhaust
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/068 : Engine exhaust temperature
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: F02D 2200/0802 : Temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/005 : according to engine operating conditions
• CPC Class Codes: F02D 41/123 : the fuel injection being cut-off
• CPC Class Codes: F02D 9/04 : concerning exhaust conduits throttle valves, or arrangements thereof in conduits F02D9/08
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/905 : Combustion engine

Abstract

In an engine mounted on a hybrid vehicle, even in an atmosphere that readily cools down a catalyst by relatively low-temperature gaseous exhausts, for example, under a fuel cut control, the structure of the invention quickly warms up the catalyst and maintains a conversion efficiency of the gaseous exhausts at a high level. When it is determined that an engine 10 is in operation and the fuel cut control is being performed, a reflux valve is turned on to reflux the gaseous exhausts into an intake conduit. This control procedure enables the relatively low-temperature gaseous exhausts to be refluxed to the intake conduit, instead of flowing into the catalyst, thereby preventing the catalyst from being cooled down.

Claims

1. A hybrid vehicle, comprising:

a motor connected to a drive shaft, which drives wheels, for rotating said drive shaft;

an engine for generating energy required for driving said hybrid vehicle;

a catalyst disposed in an exhaust conduit of said engine for converting gaseous exhausts;

a generator driven by the engine; and

a catalyst temperature control apparatus comprising;

engine power regulation means for regulating an engine power of said engine;

exhaust temperature detection means for measuring a temperature of either one of said gaseous exhausts and said catalyst; and

engine power control means for, when the temperature measured by said exhaust temperature detection means is not higher than a predetermined value, carrying out a transient control that temporarily increases the engine power to raise the temperature of said gaseous exhausts via said engine power regulation means so that the temperature of the catalyst is increased to the predetermined value, wherein the transient control carried out by said engine power control means regulates an amount of electricity generated by said generator.

2. The hybrid vehicle in accordance with claim 1,

wherein the transient control carried out by said engine power control means increases an engine torque while keeping an engine speed at a substantially constant level.

3. The hybrid vehicle in accordance with claim 2, further comprising a storage battery being charged with the electricity generated by said generator,

wherein the transient control carried out by said engine power control means enables said storage battery to be charged with the electricity generated by said generator.

4. The hybrid vehicle in accordance with claim 1,

wherein the transient control carried out by said engine power control means increases an engine speed while keeping an engine torque at a substantially constant level.

5. The hybrid vehicle in accordance with claim 4, further comprising a storage battery being charged with the electricity generated by said generator,

wherein the transient control carried out by said engine power control means enables said storage battery to be charged with the electricity generated by said generator.

6. The catalyst temperature control apparatus for a hybrid vehicle having a motor connected to a drive shaft, which drives wheels, for rotating said drive shaft;

an engine for generating energy required for driving said hybrid vehicle; and

a catalyst disposed in an exhaust conduit of said engine for converting gaseous exhausts, said catalyst temperature control apparatus comprising;

engine power regulation means for regulating an engine power of said engine;

exhaust temperature detection means for measuring a temperature of either one of said gaseous exhausts and said catalyst;

engine power control means for, when the temperature measured by said exhaust temperature detection means is not higher than a predetermined value, carrying out a transient control that temporarily increases the engine power to raise the temperature of said gaseous exhausts, via said engine power regulation means;

a generator driven by said engine;

a storage battery being charged with the electricity generated by said generator; and

remaining charge detection means for measuring a remaining charge of said storage battery,

wherein the transient control carried out by said engine power control means is based on the remaining charge measured by said remaining charge detection means, so as to increase an engine torque while keeping an engine speed at a substantially constant level when the remaining charge is not less than a predetermined level, and increase the engine speed while keeping the engine torque at a substantially constant level when the remaining charge is less than said predetermined level.

7. The catalyst temperature control apparatus in accordance with claim 6, wherein said exhaust temperature detection means comprises temperature estimation means for estimating the temperature of either one of said gaseous exhausts and said catalyst based on a driving state of said engine.

8. The catalyst temperature control apparatus in accordance with claim 6,

wherein said exhaust temperature detection means comprises:

temperature detection means for directly measuring a first temperature of either one of said gaseous exhausts and said catalyst and outputting said first temperature; and

temperature estimation means for estimating a second temperature of either one of said gaseous exhausts and said catalyst based on a driving state of said engine and outputting second temperature,

when a difference between said first temperature detected by said temperature detection means and said second temperature estimated by said temperature estimation means is not less than a predetermined level, said exhaust temperature detection means output said second temperature.

9. The catalyst temperature control apparatus in accordance with claim 6, wherein said predetermined level is a learned value obtaining by learning the difference between said first temperature and said second temperature.