System for controlling particulate filter temperature

• US 20030145582A1
• Filed: 02/01/2002
• Published: 08/07/2003
• Est. Priority Date: 02/01/2002
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Miller, Paul R., Bunting, Bruce G., Radovanovic, Rod, Suresh, S. Arvind, Stoia, Bradlee J.
• Granted Patent: US 6,901,751 B2
• Time in Patent Office: Days
• US Class Current: 60/297
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 46/444 by flow measuring
• CPC Class Codes: B01D 46/446 by pressure measuring
• CPC Class Codes: B01D 46/448 by temperature measuring
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• 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 2240/486 Operating parameters
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2250/16 : by display
• CPC Class Codes: B60L 2250/26 : by pedal actuation
• CPC Class Codes: B60L 2270/12 : of exhaust
• CPC Class Codes: B60L 3/0023 : Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• 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: 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 20/15 : Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/143 : Alarm means
• CPC Class Codes: B60W 2510/068 : Engine exhaust temperature
• CPC Class Codes: B60Y 2300/476 : Regeneration of particle filters
• CPC Class Codes: F01N 11/002 : the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
• CPC Class Codes: F01N 11/005 : the temperature or pressure being estimated, e.g. by means of a theoretical model
• CPC Class Codes: F01N 2430/00 : Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
• CPC Class Codes: F01N 2430/06 : by varying fuel-air ratio, e.g. by enriching fuel-air mixture
• CPC Class Codes: F01N 2550/04 : Filtering activity of particulate filters
• 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 9/002 : of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F01N 9/005 : using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
• CPC Class Codes: F01N 9/007 : Storing data relevant to operation of exhaust systems for later retrieval and analysis, e.g. to research exhaust system malfunctions
• CPC Class Codes: F02B 37/00 : Engines characterised by provision of pumps driven at least for part of the time by exhaust
• 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 2041/0265 : to decrease temperature of the exhaust gas treating apparatus
• CPC Class Codes: F02D 2200/0802 : Temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 2200/503 : Battery correction, i.e. corrections as a function of the state of the battery, its output or its type
• CPC Class Codes: F02D 41/0235 : in relation with the state of the exhaust gas treating apparatus control of exhaust gas treating apparatus per se F01N
• CPC Class Codes: F02D 41/029 : the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: F02D 41/1445 : the characteristics being related to the exhaust flow
• CPC Class Codes: F02D 41/1448 : the characteristics being an exhaust gas pressure
• CPC Class Codes: F16H 2300/14 : Selecting a state of operation, e.g. depending on two wheel or four wheel drive mode
• 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 903/917 : with transmission for changing gear ratio
• 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

A system for controlling the temperature of a particulate filter coupled to an exhaust outlet of an internal combustion engine includes a controller responsive to volumetric flow and temperature of exhaust gas to determine a filter regeneration parameter. In a hybrid electric-engine vehicle application, various control strategies are implemented as a function of the regeneration parameter to control exhaust gas temperature suitably for proper regeneration of the particulate filter. Such strategies include shifting the duty cycle of the engine toward lower engine speed operation along lines of constant power output, modifying the ratio of electrical power and engine power and controlling recharging of the battery supplying electrical energy to the vehicle'"'"'s electric drive motor under vehicle deceleration conditions. In vehicle applications including a transmission coupled directly to the engine, shift points of the transmission are modified as a function of the regeneration parameter to control exhaust gas temperature.

Claims

1. System for controlling particulate filter temperature, the system comprising:

an internal combustion engine producing exhaust gas at an exhaust outlet;

a particulate filter having a filter inlet fluidly coupled to said exhaust outlet and a filter outlet;

means for determining a pressure differential between said filter inlet and said filter outlet;

means for determining a volumetric flow rate of said exhaust gas entering said filter inlet; and

a control circuit determining a regeneration parameter as a function of said pressure differential and said volumetric flow rate, said control circuit controlling temperature of said particulate filter as a function of said regeneration parameter.

2. The system of claim 1 wherein the system is part of a hybrid engine-electric vehicle configured to drive the vehicle according to a ratio of electric power produced by an electric motor and engine output power produced by said engine.

3. The system of claim 2 further including a temperature sensor producing a temperature signal indicative of exhaust gas temperature exiting said filter outlet;

wherein said control circuit is responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to control said particulate filter temperature by monitoring said temperature signal and commanding reduced engine rotational speeds along lines of constant engine output power to thereby increase temperature of said exhaust gas and therefore said temperature of said particulate filter if said temperature signal is not greater than a regeneration temperature for at least a predefined portion of one of a temperature signal monitoring time period and a number of measurements of said temperature signal.

4. The system of claim 2 wherein said electric motor is responsive to electrical energy provided by a rechargeable energy source to produce said electrical power, and wherein the system further includes a first generator responsive to engine output power to recharge said energy source;

and wherein said control circuit is operable to control said ratio of electrical power and engine output power, said control circuit responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to control said temperature of said particulate filter by periodically increasing said ratio of said electrical power and said engine power to facilitate discharging of said energy source so that increased engine output power is then produced to recharge said energy source, said increased engine output power resulting in an increase in temperature of said exhaust gas and therefore an increase in said temperature of said particulate filter.

5. The system of claim 2 wherein said electric motor includes a second generator coupled to a drive axle of said vehicle, said electric motor responsive in a motor mode to electrical energy provided by a rechargeable energy source to drive at least one wheel coupled to said drive axle, and in a generator mode to torque produced by said drive axle to recharge said energy source with said second generator;

and wherein said control circuit is operable to determine an acceleration value indicative of vehicle acceleration, said control circuit responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to control said temperature of said particulate filter by inhibiting recharging of said energy source by said electric motor operating in said generator mode if said acceleration value is less than an acceleration threshold value so that increased engine output power is then produced to recharge said energy source, said increased engine output power resulting in an increase in temperature of said exhaust gas and therefore an increase in said temperature of said particulate filter.

6. The system of claim 2 further including a memory unit in communication with said control circuit, said control circuit responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to log a corresponding fault code within said memory unit.

7. The system of claim 6 wherein said control circuit is further responsive to said regeneration parameter falling within said predefined range of regeneration parameters to activate a corresponding warning light.

8. The system of claim 2 wherein said control circuit is configured to define a number of boundaries each as a different function of said differential pressure between said filter inlet and said filter outlet and of said volumetric flow rate of exhaust gas entering said filter inlet.

9. The system of claim 8 further including a memory unit having a map stored therein defining said number of boundaries, said control circuit defining said number of boundaries by extracting said map from said memory unit.

10. The system of claim 8 further including a memory unit, said control circuit responsive to said regeneration parameter falling within a first regeneration region bounded by an axis of zero-valued volumetric flow rates of exhaust gas entering said filter inlet and an adjacent one of said number of boundaries to log a low back pressure fault within said memory unit.

11. The system of claim 10 wherein said control circuit is further responsive to said regeneration parameter falling within said first regeneration region to activate a warning light.

12. The system of claim 10 further including a temperature sensor producing a temperature signal indicative of exhaust gas temperature exiting said filter outlet;

wherein said control circuit is responsive to said regeneration parameter failing within a second regeneration region bounded by said first regeneration region and an adjacent one of said number of boundaries to execute a first control strategy to control said temperature of said particulate filter by monitoring said temperature signal and commanding reduced engine rotational speeds along lines of constant engine output power to thereby increase temperature of said exhaust gas and therefore said temperature of said particulate filter if said temperature signal is not greater than a regeneration temperature for at least a predefined portion of one of a temperature signal monitoring time period and a number of measurements of said temperature signal.

13. The system of claim 12 wherein said electric motor is responsive to electrical energy provided by a rechargeable energy source to produce said electrical power, the system further including a first generator responsive to engine output power to recharge said energy source;

and wherein said control circuit is operable to control said ratio of electrical power and engine output power, said control circuit responsive to said regeneration parameter falling within a third regeneration region bounded by said second regeneration region and an adjacent one of said number of boundaries to execute said first control strategy and to execute a second control strategy operable to control said temperature of said particulate filter by periodically increasing said ratio of said electrical power and said engine power to facilitate discharging of said energy source so that increased engine output power is then produced to recharge said energy source, said increased engine output power resulting in an increase in temperature of said exhaust gas and therefore an increase in said temperature of said particulate filter.

14. The system of claim 13 wherein said electric motor includes a second generator coupled to a drive axle of said vehicle, said electric motor responsive in a motor mode to electrical energy provided by a rechargeable energy source to drive at least one wheel coupled to said drive axle, and in a generator mode to torque produced by said drive axle to recharge said energy source with said second generator;

and wherein said control circuit is operable to determine an acceleration value indicative of vehicle acceleration, said control circuit responsive to said regeneration parameter falling within a fourth regeneration region bounded by said third regeneration region and an adjacent one of said number of boundaries to execute said first and second control strategies and to execute a third control strategy to control said temperature of said particulate filter by inhibiting recharging of said energy source by said electric motor operating in said generator mode if said acceleration value is less than an acceleration threshold value so that increased engine output power is then produced to recharge said energy source, said increased engine output power resulting in an increase in temperature of said exhaust gas and therefore an increase in said temperature of said particulate filter.

15. The system of claim 14 wherein said control circuit responsive to said regeneration parameter falling within a fifth regeneration region bounded by said fourth regeneration region and an axis of zero-valued pressure differentials between said inlet and said outlet of said particulate filter to log a plugged particulate filter fault within said memory unit.

16. The system of claim 15 wherein said control circuit is further responsive to said regeneration parameter falling within said fifth regeneration region to activate a warning light.

17. The system of claim 1 further including a transmission coupled to said engine, said transmission including a number of automatically selectable gear ratios.

18. The system of claim 17 wherein said control circuit is responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to command automatic shifting of said transmission according to a default engine speed shift point schedule.

19. The system of claim 17 wherein said control circuit is responsive to said regeneration parameter falling within a predefined range of regeneration parameter values to command automatic shifting of said transmission according to a shift schedule having lower engine speed shift points than those of a default engine speed shift point schedule.

20. The system of claim 17 wherein said control circuit is configured to define a number of boundaries each as a different function of said differential pressure between said inlet and said outlet of said particulate filter and of said volumetric flow rate of exhaust gas entering said inlet of said particulate filter.

21. The system of claim 20 further including a memory unit having a map stored therein defining said number of boundaries, said control circuit defining said number of boundaries by extracting said map from said memory unit.

22. The system of claim 20 further including a memory unit, said control circuit responsive to said regeneration parameter falling within a first regeneration region bounded by an axis of zero-valued volumetric flow rates of exhaust gas entering said inlet of said particulate filter and an adjacent one of said number of boundaries to log a low back pressure fault within said memory unit.

23. The system of claim 22 wherein said control circuit is further responsive to said regeneration parameter falling within said first regeneration region to activate a warning light.

24. The system of claim 22 wherein said control circuit is responsive to said regeneration parameter falling within a second regeneration region bounded by said first regeneration region and an adjacent one of said number of boundaries to command automatic shifting of said transmission according to a default engine speed shift point schedule.

25. The system of claim 24 wherein said control circuit is responsive to said regeneration parameter falling within a third regeneration region bounded by said second regeneration region and an adjacent one of said number of boundaries to command automatic shifting of said transmission according to a first shift point schedule having lower engine speed shift points than those of said default engine speed shift point schedule, said engine resultantly producing higher exhaust gas temperatures over those produced according to said default engine speed shift point schedule, thereby increasing said temperature of said particulate filter.

26. The system of claim 25 wherein said control circuit is responsive to said regeneration parameter falling within a fourth regeneration region bounded by said third regeneration region and an adjacent one of said number of boundaries to control said temperature of said particulate filter by commanding automatic shifting of said transmission according to a second shift point schedule having lower engine speed shift points than those of said first shift point schedule, said engine resultantly producing higher exhaust gas temperatures over those produced according to said first shift point schedule, thereby increasing said temperature of said particulate filter.

27. The system of claim 26 wherein said control circuit is responsive to said regeneration parameter falling within a fifth regeneration region bounded by said fourth regeneration region and region and an axis of zero-valued pressure differentials between said inlet and said outlet of said particulate filter to log a plugged particulate filter fault within said memory unit.

28. The system of claim 27 wherein said control circuit is further responsive to said regeneration parameter falling within said fifth regeneration region to activate a warning light.

29. The system of claim 17 wherein said control circuit includes a memory unit and is responsive to said regeneration parameter falling below a first threshold regeneration parameter value to log a low back pressure fault in said memory unit.

30. The system of claim 29 wherein said control circuit is further responsive to said regeneration parameter falling below said first threshold regeneration parameter value to activate a warning light.

31. The system of claim 29 wherein said control circuit is responsive to said regeneration parameter exceeding a second threshold regeneration parameter value greater than said first threshold regeneration parameter value to log a plugged filter fault in said memory unit.

32. The system of claim 31 wherein said control circuit is further responsive to said regeneration parameter exceeding said second threshold regeneration parameter value to activate a warning light.

33. The system of claim 31 wherein said control circuit is responsive to said regeneration parameter falling between said first and second threshold regeneration parameter values to command automatic shifting of said transmission according to a shift point schedule that decreases engine speed shift points as a function of increasing regeneration parameter values.

34. A method of controlling the temperature of a particulate filter coupled to an exhaust outlet of an internal combustion engine, the method comprising the steps of:

determining a pressure differential across the particulate filter;

determining a volumetric flow rate of exhaust gas entering the particulate filter;

determining a regeneration parameter as a function of the pressure differential and the volumetric flow rate; and

controlling temperature of the particulate filter as a function of the regeneration parameter.

35. System for controlling particulate filter temperature, the system comprising:

an internal combustion engine producing exhaust gas at an exhaust gas outlet;

a particulate filter having an filter inlet fluidly coupled to said exhaust outlet and a filter outlet;

means for determining a temperature of said particulate filter; and

a control circuit controlling rotational speed of said engine between an idle speed and a maximum speed, said control circuit increasing said idle speed if said temperature of said particulate filter exceeds a first temperature to thereby cool said particulate filter by increasing exhaust gas flow therethrough.

36. The system of claim 35 wherein said means for determining a temperature of said particulate filter includes means for determining a temperature of said exhaust gas exiting said filter outlet.

37. The system of claim 35 wherein said control circuit is operable to increase said idle speed from a first idle speed value to a second higher idle speed value if said temperature of said particulate filter exceeds said first temperature.

38. The system of claim 37 wherein said control circuit is operable to decrease said idle speed from said second idle speed value back to said first idle speed value if said temperature of said particulate filter drops below a second temperature less than said first temperature.

39. The system of claim 38 wherein said control circuit is operable to log a fault code within a memory in communication with said control circuit if said temperature of said particulate filter exceeds a third temperature greater than said first temperature.

40. The system of claim 38 wherein said control circuit is operable to activate a warning indicator if said temperature of said particulate filter exceeds a third temperature greater than said first temperature.

41. The system of claim 35 wherein the system is part of a hybrid engine-electric vehicle configured to drive the vehicle according to a ratio of electric power produced by an electric motor and engine output power produced by said engine.

42. The system of claim 35 further including a transmission coupled to said engine and including a number of selectable gear ratios.

43. The system of claim 35 further including:

means for determining an idle parameter indicative of whether said engine is operating near said idle speed; and

means for determining a moving parameter indicative of whether a vehicle carrying said engine is moving;

and wherein said control circuit is operable to increase said idle speed only if said idle parameter indicates that said engine is operating near said idle speed and said moving parameter indicates that said vehicle is stationary.

44. A method of controlling the temperature of a particulate filter coupled to an exhaust outlet of an internal combustion engine operating at rotational speeds between an idle speed and a maximum speed, the method comprising the steps of:

determining a temperature of the particulate filter; and

increasing the idle speed if the temperature of the particulate filter exceeds a first temperature to thereby cool the particulate filter by increasing a flow rate of engine exhaust gas therethrough.

45. The method of claim 44 wherein the step of increasing the idle speed includes increasing the idle speed from a first idle speed to a second greater idle speed if the temperature of the particulate filter exceeds said first temperature.

46. The method of claim 45 further including the step of decreasing the idle speed from the second idle speed back to the first idle speed if the temperature of the particulate filter drops below a second temperature less than the first temperature.

47. The method of claim 44 further including the steps:

determining whether a vehicle carrying the engine is moving; and

determining an engine idle indicator;

and wherein the increasing step is conditioned upon the vehicle being stationary and the engine idle indicator indicating that the engine is operating near idle speed.

48. System for controlling particulate filter temperature, the system comprising:

an internal combustion engine producing exhaust gas at an exhaust gas outlet;

a particulate filter having a filter inlet fluidly coupled to said exhaust outlet and a filter outlet;

means for determining a temperature of said particulate filter;

a transmission coupled to said engine and having a number of automatically selectable gear ratios; and

a control circuit responsive to said temperature of said particulate filter exceeding a first temperature to command automatic shifting of said transmission according to a shift schedule having higher engine speed shift points than those of a default engine speed shift point schedule, said engine resultantly operating at higher engine speeds with correspondingly higher exhaust gas flow through said particulate filter to thereby cool said particulate filter.

49. The system of claim 48 wherein said means for determining a temperature of said particulate filter includes means for determining a temperature of said exhaust gas exiting said filter outlet.

50. The system of claim 48 wherein said control circuit is operable to command automatic shifting of said transmission according to said shift schedule having higher engine speed shift points than those of said default engine speed shift point schedule if said temperature of said particulate filter exceeds said first temperature.

51. The system of claim 50 wherein said control circuit is operable to command automatic shifting of said transmission according to said default engine speed shift point schedule if said temperature of said particulate filter drops below a second temperature less than said first temperature.

52. The system of claim 51 wherein said control circuit is operable to log a fault code within a memory in communication with said control circuit if said temperature of said particulate filter exceeds a third temperature greater than said first temperature.

53. The system of claim 51 wherein said control circuit is operable to activate a warning indicator if said temperature of said particulate filter exceeds a third temperature greater than said first temperature.

54. The system of claim 48 further including means for determining a moving parameter indicative of whether a vehicle carrying said engine is moving;

and wherein said control circuit is operable to command automatic shifting of said transmission according to said shift schedule having higher engine speed shift points than those of a default engine speed shift point schedule only if said moving parameter indicates that said vehicle is moving.

55. A method of controlling the temperature of a particulate filter coupled to an exhaust outlet of an internal combustion engine coupled to a transmission having a number of automatically selectable gear ratios, the method comprising the steps of:

determining a temperature of the particulate filter; and

commanding automatic shifting of the transmission according to a shift schedule having higher engine speed shift points than those of a default engine speed shift point schedule if the temperature of the particulate filter exceeds a first temperature, resulting in the engine operating at higher engine speeds with correspondingly higher exhaust gas flow through the particulate filter to thereby cool the particulate filter.

56. The method of claim 55 further including the step of commanding automatic shifting of the transmission according to the default shift schedule if the temperature of the particulate filter drops below a second temperature less than the first temperature.

57. The method of claim 55 further including the step of determining whether a vehicle carrying the engine is stationary;

and wherein the commanding step is conditioned upon the vehicle not being stationary.