Exhaust purification system for hybrid vehicle

• US 20070204594A1
• Filed: 02/27/2007
• Published: 09/06/2007
• Est. Priority Date: 03/02/2006
• Status: Abandoned Application

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ishii, Hiroshi
• Application Number:
  US11/711,438
• Publication Number:
  US 20070204594A1
• Time in Patent Office: Days
• US Class Current: 60/274
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 7/10 Dynamic electric regenerative braking B60L7/22 takes precedence
• 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 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 20/16 for reducing engine exhaust emissions
• CPC Class Codes: B60W 2050/0026 Lookup tables or parameter maps
• CPC Class Codes: B60W 2510/068 Engine exhaust temperature
• CPC Class Codes: B60W 2530/12 Catalyst or filter state
• CPC Class Codes: B60Y 2300/476 Regeneration of particle filters
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 3/0871 Regulation of absorbents or adsorbents, e.g. purging by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/106 : Auxiliary oxidation catalysts
• CPC Class Codes: F02D 2041/026 : using an external load, e.g. by increasing generator load or by changing the gear ratio
• CPC Class Codes: F02D 2200/0804 : Estimation of the temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 2200/0812 : Particle filter loading
• CPC Class Codes: F02D 41/029 : the exhaust gas treating apparatus being a particulate filter
• 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 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles

Abstract

An exhaust purification system for a hybrid vehicle with an internal combustion engine and an electric motor capable of being driven by the engine includes a battery, an exhaust gas passage, an exhaust purification device and at least one controller. The battery is connected to the electric motor and selectively charged with electric power generated by the electric motor. The exhaust gas passage is connected to the internal combustion engine and the exhaust purification device is disposed in the exhaust gas passage. The at least one controller selectively performs regeneration control of the exhaust purification device and controls the engine and the electric motor to ensure that the battery does not become overcharged.

Claims

1. An exhaust purification system for a hybrid vehicle comprising:

an internal combustion engine having an exhaust purification device disposed in an exhaust gas passage of the engine to treat exhaust gas components contained in exhaust gas from the engine;

a motor generator capable of generating electric power by being driven by the engine;

a battery arranged and configured to be selectively charged with electric power generated by the motor generator; and

at least one controller arranged and configured to selectively perform a regeneration control of the exhaust purification device under a predetermined regeneration condition, in which deposits accumulated in the exhaust purification device are burned and removed by increasing exhaust gas temperature through an increase in power output of the engine, and an excess power output caused by the increase in power output of the engine is used to generate the electric power by the motor generator, and

wherein the at least one controller is further arranged and configured to control the engine and the motor generator so that the battery is prevented from overcharging by the electric power associated with the regeneration control of the exhaust purification device.

2. The exhaust purification system according to claim 1, wherein a state of charge of the battery is reduced by selectively increasing a power output of the motor generator before the regeneration control.

3. The exhaust purification system according to claim 2, wherein a target value of the state of charge of the battery is determined corresponding to an accumulated level of the deposits in the exhaust purification device.

4. The exhaust purification system according to claim 3, wherein the target value of the state of charge of the battery becomes smaller as the accumulated level of the deposits becomes larger.

5. The exhaust purification system according to claim 2, wherein a determination as to timing for increasing the power output of the motor generator before the regeneration control is made in accordance with an accumulated level of the deposits.

6. The exhaust purification system according to claim 2, further including a compensation selectively adjusting a distribution of the power output of the engine with respect to a requested total power output of the vehicle.

7. The exhaust purification system according to claim 6, wherein the requested total power output where the engine starts the power output of the internal combustion engine is set to increase with the compensation.

8. The exhaust purification system according to claim 6, wherein an upper limit value that is set for the power output of the engine is set to reduce with the compensation.

9. The exhaust purification system according to claim 6, wherein the distribution of the power output of the engine with respect to at least one of the requested total power output and the power output of the motor generator is set to reduce with the compensation.

10. The exhaust purification system according to claim 6, wherein a compensation amount of the compensation is varied corresponding to a deviation amount between an actual value and a target value of the state of charge of the battery.

11. The exhaust purification system according to claim 10, wherein the compensation selectively performs when the actual value of the state of charge is larger than the target value of the state of charge, but not to perform when the actual value is smaller than the target value.

12. The exhaust purification system according to claim 1, wherein a fuel injection timing of the engine is retarded in the regeneration control of the exhaust purification device.

13. The exhaust purification system according to claim 12, wherein at least one of an amount of the increase in power output of the engine and an amount of the electric power generated by the motor generator associated with the increase in power output of the engine is determined so that a retard amount of the fuel injection timing is prevented from falling within a range of retard amount that causes exhaust gas aggravation or oil dilution.

14. The exhaust purification system according to claim 12, wherein when the state of charge of the battery is lower than a first predetermined value, the electric power generation by the increase in power output of the engine is performed without retarding the fuel injection timing, and when the state of charge of the battery is higher than the first predetermined value, the fuel injection timing is retarded and the electric power generation by the increase in power output of the internal combustion engine is performed.

15. The exhaust purification system according to claim 14, wherein the power output of the engine during the regeneration control is set at a fixed value regardless of a requested total power output.

16. The exhaust purification system according to claim 14, wherein at least one of an amount of the increase in power output of the engine and an amount of the electric power generated by the motor generator associated with the increase in power output of the engine in the case where the state of charge of the battery is larger than the first predetermined value is smaller than that in the case where the state of charge is lower than the first predetermined value.

17. The exhaust purification system according to claim 12, wherein a current control is performed so that an electric power generation efficiency of the motor generator is reduced when the motor generator generate the electric power.

18. The exhaust purification system according to claim 14, wherein a current control is performed so that an electric power generation efficiency of the motor generator is reduced when the state of charge of the battery is greater than a second predetermined value that is higher than the first predetermined value.

19. The exhaust purification system according to claim 17, wherein the current control is performed corresponding to an amount of the electric power generated by the motor generator at which the power output of the engine is larger than the requested total power output.

20. The exhaust purification system according to claim 14, wherein, when the state of the charge of the battery is greater than a second predetermined value that is greater than the first predetermined value, the hybrid vehicle is driven only by the power output of the motor generator and the engine is rotated by the motor generator to supply air to the exhaust purification device.

21. The exhaust purification system according to claim 20, wherein the engine is rotated by the motor generator at a rotational speed where an amount of the air is capable of elevating the temperature of the exhaust purification device through combustion in the exhaust purification device.

22. The exhaust purification system according to claim 20, wherein, under a condition where the exhaust purification device is cooled down by the air supplied to the exhaust purification device when the hybrid vehicle is driven only by the power output of the motor generator, the rotation of the engine driven by the motor generator is stopped so that the air supply to the exhaust purification device is stopped.

23. The exhaust purification system according to claim 20, wherein, under a condition where the exhaust purification device is cooled down by the air supplied to the exhaust purification device when the hybrid vehicle is driven by the power output of the motor generator, a throttle valve of the engine is fully closed so that the air supply to the exhaust purification device is stopped.

24. The exhaust purification system according to. Claim 20, wherein, under a condition where the exhaust purification device is cooled down by the air supplied to the exhaust purification device when the hybrid vehicle is driven by the power output of the motor generator, an EGR valve of the engine is fully opened so that the air supply to the exhaust purification device is reduced.

25. The exhaust purification system according to claim 14, wherein in the event that the state of charge of the battery is larger than a second predetermined value that is larger than the first predetermined value, when the exhaust purification device is inactive, a current control is performed so that an electric power generation efficiency of the motor generator is reduced, and when the exhaust purification device is active, the hybrid vehicle is driven by the power output of the motor generator and the engine is rotated by the motor generator, providing an air supply to the exhaust purification device.

26. An exhaust purification system for a hybrid comprising:

an internal combustion engine;

first means for treating exhaust gas components contained in exhaust gas from the engine;

second means for generating electric power by being driven by the engine;

a battery being selectively charged with electric power generated by the second means; and

third means for performing a regeneration of the first means under a predetermined regeneration condition, in which deposits accumulated in the first means are removed by increasing exhaust gas temperature through an increase in power output of the internal combustion engine, and an excess power output caused by the increase in power output of the internal combustion engine is used to generate electric power by the second means, and wherein the internal combustion engine and the second means is controlled so that the battery is prevented from overcharging by the electric power associated with the regeneration of the first means.

27. A method of controlling an exhaust purification system for a hybrid vehicle including an engine and an electric motor capable of being driven by the engine, a battery being selectively charged with electric power generated by the electric motor;

an exhaust purification device provided in an exhaust passageway of the engine, comprising;

performing a regeneration of an exhaust purification device under a predetermined regeneration condition in which deposits accumulated in the exhaust purification device is removed by increasing exhaust gas temperature through an increase in power output of an engine;

absorbing an excess power output associated with the increase in power output of the engine by an electric motor; and

controlling the engine and the electric motor so that a battery is prevented from overcharging by the electric power caused by the regeneration of the exhaust purification device.

28. The method as recited in claim 27, wherein a power output of the electric motor is increased before performing the regeneration such that a state of charge of the battery is reduced.

29. The method as recited in claim 27, wherein a fuel injection timing of the engine is retarded during the regeneration of the exhaust purification device.