Regeneration control of particulate filter, particularly in a hybrid electric vehicle

• US 6,422,001 B1
• Filed: 10/10/2000
• Issued: 07/23/2002
• Est. Priority Date: 10/10/2000
• Status: Expired due to Term

• Current Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Inventors: Sherman, James Alan, Lyons, Arthur Paull
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): TRAN, BINH Q
• Application Number:
  US09/785,723
• Time in Patent Office: 651 Days
• Field of Search: 602/74, 602/95, 602/97, 603/00, 603/11, 602/85, 180/65.1, 180/65.2, 180/65.3, 180/65.4
• US Class Current: 60/274
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60Y 2300/476 Regeneration of particle filters
• 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 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: F02D 2041/026 using an external load, e.g. by increasing generator load or by changing the gear ratio
• CPC Class Codes: F02D 2200/0802 Temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/0245 by increasing temperature of the exhaust gas leaving the engine
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• 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

Abstract

A method for regeneration of particulate filters or traps in the context of a hybrid electric vehicle includes the step of measuring the back pressure of the filter, and adjusting the engine parameters when the back pressure exceeds a particular value to increase the exhaust temperature, to aid in regeneration. In one mode, the engine speed and engine load are both reset toward particular target values. In another version in which the engine load includes an energy storage device such as a battery, increasing the load includes the step of increasing the battery charge level setpoint. Additionally, for those situations in which the battery cannot accept more charge, a power-dissipating resistor is coupled to an electric source to increase the load. In yet another version, the use of the electrical resistor is made dependent upon the temperature of the filter during regeneration.

Claims

1. A method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, the steps comprising:

a) providing an internal combustion engine having a range of selectable operating speeds and producing exhaust gas comprising particulate matter, said exhaust gas being temperature dependent, at least in part, upon a selected operating speed of said internal combustion engine;

b) providing an electrical generator operatively connected to and powered by said internal combustion engine;

c) passing said exhaust gas from said internal combustion engine through a regenerative particulate filter for removing and capturing therein at least a portion of said particulate matter from said exhaust gas, said particulate filter having a back pressure dependent at least in part upon a quantity of said particulate matter captured therein;

d) generating a first back pressure signal representative of a first, predetermined back pressure of said particulate filter;

e) upon receipt of said first back pressure signal, setting said operating speed of said internal combustion engine to a speed selected from the low end of said range of selectable operating speeds; and

f) controlling a load applied to said internal combustion engine substantially simultaneously with said setting step (e);

whereby said temperature of said exhaust gas is increased and a temperature of said particulate filter is also increased in response thereto, thereby facilitating the cleaning thereof.

2. The method for cleaning a regenerative particulate filter associated with a particulate-generating, internal combustion engine, as recited in claim 1, wherein said controlling a load step (f) further comprises the sub-steps:

i) coupling the output of said generator to an electrical load; and

ii) adjusting said electrical load until a desired loading is applied to said internal combustion engine.

3. The method for cleaning a regenerative particulate filter associated-with a particulate-generating internal combustion engine, as recited in claim 2, herein said electrical load comprises a resistive dissipating device.

4. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 3, wherein said resistive dissipating device comprises a load resistor.

5. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 2, wherein said electrical load comprises an energy storage device.

6. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 5, wherein said energy storage device comprises at least one from the group:

battery and ultracapacitor.

7. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 5, the steps further comprising:

a) generating a second back pressure signal representative of a second, predetermined back pressure of said regenerative particulate filter, said second predetermined back pressure being lower than said first, predetermined back pressure; and

b) modifying a set point associated with said energy storage device so that said increased energy output may later be accommodated by said energy storage device while minimizing overcharging thereof.

8. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 1, wherein said controlling a load step (f) is responsive to a temperature of at least a portion of said regenerative particulate filter.

9. The method for cleaning a regenerative particulate filter associated with a particulate-generating internal combustion engine, as recited in claim 1, wherein said internal combustion engine is adapted to propel a vehicle having a traction demand, and wherein said controlling a load step (f) is responsive to said traction demand so as to operate said internal combustion engine near a torque-speed temperature isotherm.