Exhaust emission control apparatus for internal combustion engine

• US 6,032,461 A
• Filed: 04/20/1998
• Issued: 03/07/2000
• Est. Priority Date: 10/30/1995
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Itou, Takaaki, Igarashi, Kouhei, Kinugasa, Yukio
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): TRAN, BINH Q
• Application Number:
  US09/065,016
• Time in Patent Office: 687 Days
• Field of Search: 60/276, 60/277, 60/285, 60/286, 60/295, 60/297, 701/201
• US Class Current: 60/295
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 13/0097 the purifying devices are arranged in a single housing
• CPC Class Codes: F01N 2240/16 an electric heater, i.e. a resistance heater
• CPC Class Codes: F01N 2260/04 for regeneration or reactivation, e.g. of catalyst
• 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 3/0231 using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]
• CPC Class Codes: F01N 3/0256 the fuel being ignited by electrical means
• CPC Class Codes: F01N 3/027 using electric or magnetic heating means
• 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 3/0885 Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps
• CPC Class Codes: F01N 3/20 specially adapted for catalytic conversion F01N3/22 takes precedence; Methods of operation or control of catalytic converters
• CPC Class Codes: F01N 3/2013 using electric or magnetic heating means
• CPC Class Codes: F01N 3/2882 Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices combined with absorbents or adsorbents only F01N3/0814; combined with particulate filters F01N3/035
• 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: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02D 2200/0806 NOx storage amount, i.e. amount of NOx stored on NOx trap
• CPC Class Codes: F02D 2200/0812 Particle filter loading
• CPC Class Codes: F02D 2200/701 Information about vehicle position, e.g. from navigation system or GPS signal
• CPC Class Codes: F02D 41/027 to purge or regenerate the exhaust gas treating apparatus
• CPC Class Codes: F02D 41/0275 : the exhaust gas treating apparatus being a NOx trap or adsorbent
• 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 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

To provide an exhaust gas purifying system for an internal combustion engine capable of executing an optimal regenerative operation by predicting a temperature of an absorbent based on running state information.

There are predicted the amount of nitrogen oxides (NO_x) to be absorbed by an absorbent 125 incorporated in a catalyst 124 and the temperature of the absorbent, based on the running state information obtained from a car navigation system 141 or traffic information service receiver 142, and the regenerative operation schedule is determined based on the prediction. Thus, the regenerative operation is conducted at the timing where NO_x has been duly absorbed by the absorbent and the absorbent temperature is lower than a predetermined temperature, so that the leakage of NO_x into the exterior of a vehicle can be restrained.

Claims

1. An exhaust gas purifying system for an internal combustion engine, comprising:

means for trapping polluting components of exhaust gas emitted from the internal combustion engine;

means for regenerating the trapping means by removing the polluting components trapped in the trapping means;

means for predicting a future running condition of a vehicle in which the engine is mounted;

means for predicting a property of the exhaust gas based on the predicted future running condition;

means for determining a timing at which the trapping means should be regenerated by the removal means in accordance with the predicted exhaust gas property; and

means for executing regenerating of the trapping means by the removing means at the timing determined by the regeneration timing determining means.

2. An exhaust gas purifying system according to claim 1, wherein:

the exhaust gas property predicting means is an exhaust gas temperature predicting means for predicting the temperature of the exhaust gas emitted from said internal combustion engine based on the vehicle running condition predicted by said running condition predicting means.

3. An exhaust gas purifying system according to claim 2, wherein:

the trapping means is a catalyst for trapping nitrogen oxide in the exhaust gas when the exhaust gas is in a lean state;

the removing means enriches the exhaust gas to regenerate the catalyst by releasing nitrogen oxide trapped in the catalyst;

the regeneration timing determining means determines the regeneration timing of the catalyst based on the predicted future exhaust gas temperature; and

the regeneration executing means enriches the exhaust gas at the enriching timing determined by the enriching timing determining means.

4. An exhaust gas purifying system according to claim 3, wherein the enriching timing determining means determines the regeneration timing to coincide with a time point at which the exhaust gas property predicting means reaches a predetermined regeneration threshold.

5. An exhaust gas purifying system according to claim 3, wherein the enriching timing determining means determines the enriching timing determining means determines the regeneration timing to coincide with a time point at which the exhaust gas property predicting means is lower than a predetermined regeneration threshold.

6. An exhaust gas purifying system according to claim 1, wherein

the trapping means is a particulate filter for trapping particulate emitted from the internal combustion engine;

the removing means regenerates the particulate filter by burning off particulate trapped therein;

the regeneration timing determining means determines the regeneration timing based on the predicted future exhaust gas property; and

the regeneration executing means executes regeneration of the particulate filter at the particulate filter regenerating timing determined by the regenerating timing determining means.

7. An exhaust gas purifying system according to claim 6, wherein the exhaust gas property predicting means predicts a temperature of the exhaust gas based the predicted running condition.

8. An exhaust gas purifying system according to claim 7, wherein the regeneration timing determined by the regeneration timing determining means determines is a time at which the predicted exhaust gas temperature is lower than a predetermined regeneration threshold.

9. An exhaust gas purifying system according to claim 6, wherein the regeneration timing determined by the regeneration timing determining means determines is a time at which the predicted exhaust gas property reaches a predetermined regeneration threshold.

10. An exhaust gas purifying system according to claim 6, wherein the particulate filter regenerating means is at least one of a means for slightly closing a throttle valve of the engine, an electric heater for heating the exhaust gas and means for burning fuel in the exhaust gas to heat the exhaust gas.

11. An exhaust gas purifying system according to claim 6, wherein:

the particulate filter contains a catalyst for naturally burning off particulate; and

when the exhaust gas temperature is higher than about 600°

C., the regeneration executing means executes regeneration of the particulate filter by natural burning without activating the particulate filter regenerating means.

12. An exhaust gas purifying system according to claim 6, further comprising:

an oxidization catalyst arranged upstream of the particulate filter for absorbing nitrogen monoxide contained in the exhaust gas when the exhaust gas temperature is lower than 250°

C. and for converting nitrogen monoxide into nitrogen dioxide to release nitrogen monoxide when the exhaust gas temperature is between about 250°

C. and 400°

C.;

wherein, when the exhaust gas temperature is between about 250°

C. and 400°

C., the regeneration executing means executes regeneration of the particulate filter by oxidizing particulate via the nitrogen dioxide without operating particulate filter regenerating means.

13. An exhaust gas purifying system according to claim 1, further comprising:

means for judging whether the predicted running condition agrees with an actual running condition and whether the predicted exhaust gas property agrees with an actual exhaust gas property; and

means for re-predicting, when the agreement judging means judges that the predicted running condition does not agree with the actual running condition, the future vehicle running condition and re-predicting the future exhaust gas property based on the re-predicted running condition.