Driving apparatus and method for hybrid vehicle

• US 6,301,529 B1
• Filed: 07/20/2000
• Issued: 10/09/2001
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Shirakawa, Takashi, Miura, Manabu, Itoyama, Hiroyuki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/620,972
• Time in Patent Office: 446 Days
• Field of Search: 701/22, 701/69, 701/90, 701/109, 701/103, 477/15, 180/65.2, 180/65.4, 180/65.1, 602/74, 602/84, 602/85
• US Class Current: 701/22
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 2240/445 Temperature
• 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 10/10 including control of change-speed gearings
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/068 Engine exhaust temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: F01N 3/2013 using electric or magnetic heating means
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• 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: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/918 Continuously variable
• CPC Class Codes: Y10S 903/945 Characterized by control of gearing, e.g. control of transmission ratio

Abstract

In driving apparatus and method for a hybrid vehicle, a controller is provided and programmed: to calculate a target driving force [tFd], the target driving force representing a target value of a vehicular driving force; to calculate a basic target engine speed [tNinb] on the basis of tFd, the basic target engine speed representing a basic target value of the engine speed; to calculate a power generation request quantity [tWg], the power generation request quantity representing a power to be generated by the motor/generator; to calculate a basic target engine torque [tTeg] on the basis of tFd, tWg, and tNinb, the basic target engine torque representing an engine torque to be developed when an output required for a vehicular drive and for a power drive of the motor/generator is developed at tNinb; to calculate a limit torque [tTlim] during an occurrence of a power generation request on the basis of tNinb, this limit torque representing a limit torque of the engine when the engine is driven at the tNinb, satisfying a demand for an exhaust performance of the engine; to set a target engine speed [tNin] to either tNinb or a value different from tNinb according to a result of comparison between tTeg and tTlim; and to control the engine on the basis of tNin.

Claims

1. A driving apparatus for a hybrid vehicle, comprising:

an engine;

a motor/generator having its rotary axle linked to an output axle of the engine;

a battery electrically connected to the motor/generator; and

a controller programmed;

to calculate a target driving force [tFd], the target driving force [tFd] representing a target value of a vehicular driving force;

to calculate a basic target engine speed [tNinb] on the basis of the target driving force, the basic target engine speed [tNinb] representing a basic target value of the engine speed;

to calculate a power generation request quantity [tWg], the power generation request quantity [tWg] representing a power to be generated by the motor/generator;

to calculate a basic target engine torque [tTeg] on the basis of the target driving force [tFd], the power generation request quantity [tWg], and the basic target engine speed [tNinb], the basic target engine torque [tTeg] representing an engine torque to be developed when an output required for a vehicular drive and for a power drive of the motor/generator is developed at the basic target engine speed [tNinb];

to calculate a limit torque [tTlim] during an occurrence of a power generation request on the basis of the basic target engine speed [tNinb], the limit torque [tTlim] during the occurrence of the power generation request representing a limit torque of the engine when the engine is driven at the basic target engine speed [tNinb], satisfying a demand for an exhaust performance of the engine;

to set a target engine speed [tNin] to either the basic target engine speed [tNinb] or value different from the basic target engine speed [tNinb] according to a result of comparison between the basic target engine torque [tTeg] and the limit torque [tTlim] during the occurrence of the power generation request; and

to control the engine on the basis of the target engine speed [tNin].

2. A driving apparatus for a hybrid vehicle as claimed in claim 1, wherein the controller further programmed:

to set the target engine speed [tNin] to the basic target engine speed [tNinb] when the basic target engine torque [tTeg] is placed at a more exhaust performance favoring side than the limit torque [tTlim]; and

to set the target engine speed [Nin] to the value based on the demand for the exhaust performance of the engine when the basic target torque [tTeg] is placed at a more exhaust performance worsening side than the limit torque [tTlim].

3. A driving apparatus for a hybrid vehicle as claimed in claim 2, wherein the controller further programmed to calculate a target engine output [tWeg] on the basis of the target driving force [tFd] and the power generation request quantity [tWg], the target engine output [tWeg] representing an engine output required for the vehicular drive and for the power drive of the motor/generator;

and to set the target engine speed [tNin] to a value satisfying both of the demand on the exhaust performance of the engine and the target engine output [tWeg] when the basic target engine torque [tTeg] is placed at the more exhaust performance worsening side than the limit torque [tTlim].

4. A driving apparatus for a hybrid vehicle as claimed in claim 3, wherein the controller further programmed to calculate the limit torque [tTlim] during the occurrence of the power generation request using a control table in which a torque of the engine such that an exhaust quantity of an exhaust matter with respect to the basic target engine speed [tNinb] becomes substantially equal to a predetermined reference quantity is stored;

and to calculate the target engine speed [tNin] using another control table in which the engine speed such that the exhaust quantity of the exhaust matter with respect to the target engine output [tWeg] becomes substantially equal to the predetermined reference quantity is stored when the basic target engine torque [tTeg] is placed at the more exhaust performance worsening side than the limit torque [tTlim].

5. A driving apparatus for a hybrid vehicle as claimed in claim 4, wherein the exhaust matter is a nitride oxygen.

6. A driving apparatus for a hybrid vehicle as claimed in claim 4, wherein the exhaust matter is a particulate.

7. A driving apparatus for a hybrid vehicle as claimed in claim 4, wherein the exhaust substance is a smoke.

8. A driving apparatus for a hybrid vehicle as claimed in claim 1, wherein the controller is further programmed to calculate the limit torque [tTlim] by correcting a basic limit torque [tTlimb], calculated on the basis of the basic target engine speed [tNinb], on the basis of an EGR rate.

9. A driving apparatus for a hybrid vehicle as claimed in claim 1, wherein the controller is further programmed to calculate the power generation request quantity [tWg] on the basis of a vehicular battery charged state [SOC].

10. A driving apparatus for a hybrid vehicle as claimed in claim 1, wherein the controller is further programmed to calculate a battery request power generation [tWbat] on the basis of a vehicular battery charged state [SOC];

to calculate a catalytic converter warm-up demand power generation [tWcat] on the basis of a catalytic converter temperature [Tmpcat]; and

to calculate the power generation request quantity [tWg] on the basis of the battery request power generation [tWbat] and the catalytic converter warm-up demand power generation [tWcat].

11. A driving apparatus for a hybrid vehicle as claimed in claim 10, wherein the controller is further programmed to select one of the battery request power generation [tWbat] and the catalytic converter warm-up demand power generation [Tmpcat] which is larger than the other as the power generation request quantity [tWg].

12. A driving apparatus for a hybrid vehicle as claimed in claim 10, wherein the controller is further programmed to calculate the catalytic converter warm-up demand power generation [tWcat] in such a manner that the catalytic converter warm-up demand power generation [Tmpcat] become larger as the catalytic converter temperature [Tmpcat] becomes low.

13. A driving apparatus for a hybrid vehicle, comprising:

an engine;

a motor/generator having its rotary axle linked to an output axle of the engine;

a battery electrically connected to the motor/generator; and

a controller, the controller including;

target driving force calculating means for calculating a target driving force [tFd], the target driving force [tFd] representing a target value of a vehicular driving force;

basic target engine speed calculating means for calculating a basic target engine speed [tNinb] on the basis of the target driving force, the basic target engine speed [tNinb] representing a basic target value of the engine speed;

power generation request quantity calculating means for calculating a power generation request quantity [tWg], the power generation request quantity [tWg] representing a power to be generated by the motor/generator;

basic target engine torque calculating means for calculating a basic target engine torque [tTeg] on the basis of the target driving force [tFd], the power generation request quantity [tWg], and the basic target engine speed [tNinb], the basic target engine torque [tTeg] representing an engine torque to be developed when an output required for a vehicular drive and for a power drive of the motor/generator is developed at the basic target engine speed [tNinb];

limit torque calculating means for calculating a limit torque [tTlim] during an occurrence of a power generation request on the basis of the basic target engine speed [tNinb], the limit torque [tTlim] during the occurrence of the power generation request representing a limit torque of the engine when the engine is driven at the basic target engine speed [tNinb], satisfying a demand for an exhaust performance of the engine;

target engine speed setting means for setting a target engine speed [tNin] to either the basic target engine speed [tNinb] or a value different from the basic target engine speed [tNinb] according to a result of comparison between the basic target engine torque [tTeg] and the limit torque [tTlim] during the occurrence of the power generation request; and

controlling means for controlling the engine on the basis of the target engine speed [tNin].

14. A driving method for a hybrid vehicle, comprising:

providing an engine;

providing a motor/generator having its rotary axle linked to an output axle of the engine,

providing a battery electrically connected to the motor/generator;

calculating a target driving force [tFd], the target driving force [tFd] representing a target value of a vehicular driving force;

calculating a basic target engine speed [tNinb] on the basis of the target driving force, the basic target engine speed [tNinb] representing a basic target value of the engine speed;

calculating a power generation request quantity [tWg], the power generation request quantity [tWg] representing a power to be generated by the motor/generator;

to calculate a basic target engine torque [tTeg] on the basis of the target driving force [tFd], the power generation request quantity [tWg], and the basic target engine speed [tNinb], the basic target engine torque [tTeg] representing an engine torque to be developed when an output required for a vehicular drive and for a power drive of the motor/generator is developed at the basic target engine speed [tNinb];

calculating a limit torque [tTlim] during an occurrence of a power generation request on the basis of the basic target engine speed [tNinb], the limit torque [tTlim] during the occurrence of the power generation request representing a limit torque of the engine when the engine is driven at the basic target engine speed [tNinb], satisfying a demand for an exhaust performance of the engine;

setting a target engine speed [tNin] to either the basic target engine speed [tNinb] or a value different from the basic target engine speed [tNinb] according to a result of comparison between the basic target engine torque [tTeg] and the limit torque [tTlim] during the occurrence of the power generation request; and

controlling the engine on the basis of the target engine speed [tNin].