Exhaust gas treatment apparatus functionality check

Patent metadata

Field	Value
Publication number	US-9616387-B2
Application number	US-201314416545-A
Country	US
Kind code	B2
Filing date	Jul 24, 2013
Priority date	Jul 27, 2012
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An exhaust fluid treatment apparatus used to treat exhaust fluid emitted by a combustion engine includes a check of its functionality. A method of monitoring operation of an exhaust fluid treatment apparatus includes comparing a calculated temperature difference with an expected temperature difference associated with combustion of fuel. If the calculated temperature difference is within an acceptable margin of the expected temperature difference, further fuel injection may be permitted. If the calculated temperature difference is outside the acceptable margin of the expected temperature difference, a temperature of the exhaust gas upstream of the exhaust fluid treatment apparatus may be increased.

First claim

The invention claimed is:

1. A method of monitoring and controlling operation of an exhaust fluid treatment apparatus, the apparatus comprising a diesel oxidation catalyst comprising an inlet and an outlet, the method comprising:
receiving an input temperature data value being indicative of temperature of fluid at the inlet;
injecting a first quantity of fuel into an exhaust fluid upstream of the diesel oxidation catalyst for combustion in the diesel oxidation catalyst;
receiving an output temperature data value being indicative of temperature of fluid at the outlet;
calculating a calculated temperature difference between the input temperature data value and the output temperature data value and comparing the calculated temperature difference with an expected temperature difference associated with the quantity of fuel injected; and:
only if the calculated temperature difference is within an acceptable margin of the expected temperature difference, injecting a second quantity of fuel into the exhaust fluid for combustion in the diesel oxidation catalyst; and
if the calculated temperature difference is outside the acceptable margin of the expected temperature difference, raising a temperature of exhaust gas upstream of the inlet to the diesel oxidation catalyst.

2. The method of claim 1 wherein the step of raising a temperature of exhaust gas upstream of the inlet to the diesel oxidation catalyst comprises restricting passage of exhaust gas through a valve located upstream of the diesel oxidation catalyst inlet.

3. The method of claim 2 wherein the input temperature data value indicative of a temperature at the inlet is obtained by receiving a temperature indication upstream of the inlet and using a compensation factor to account for a likely temperature change between the temperature indication and the actual temperature at the inlet of the diesel oxidation catalyst.

4. The method of claim 2 wherein the expected temperature difference is modified to take into account expected changes in temperature attributable to reasons other than combustion of the first quantity of fuel in the diesel oxidation catalyst.

5. The method of claim 2 wherein the step of injecting a second quantity of fuel into the exhaust fluid for combustion in the diesel oxidation catalyst is delayed in the event of changing external conditions.

6. The method of claim 2 wherein there is a time delay between the step of receiving the input temperature value being indicative of temperature of fluid at the inlet and the step of receiving an output temperature data value being indicative of temperature of fluid at the outlet.

7. The method of claim 2 wherein the step of comparing the calculated temperature difference with an expected temperature difference comprises obtaining the expected temperature difference from a data library having an expected temperature difference associated with each possible first quantity of fuel.

8. The method of claim 1 wherein the step of raising a temperature of exhaust gas upstream of the inlet to the diesel oxidation catalyst comprises increasing the temperature of fluid at the inlet to in excess of 240° C., and in excess of 270° C.

9. The method of claim 1 wherein the input temperature data value indicative of a temperature at the inlet is obtained by receiving a temperature indication upstream of the inlet and using a compensation factor to account for a likely temperature change between the temperature indication and the actual temperature at the inlet of the diesel oxidation catalyst.

10. The method of claim 1 wherein the expected temperature difference is modified to take into account expected changes in temperature attributable to reasons other than combustion of the first quantity of fuel in the diesel oxidation catalyst.

11. The method of claim 1 wherein the step of injecting a second quantity of fuel into the exhaust fluid for combustion in the diesel oxidation catalyst is delayed in the event of changing external conditions.

12. The method of claim 1 wherein there is a time delay between the step of receiving the input temperature value being indicative of temperature of fluid at the inlet and the step of receiving an output temperature data value being indicative of temperature of fluid at the outlet.

13. The method of claim 12 wherein the time delay is dependent on an expected time taken for the first quantity of fuel to combust in the diesel oxidation catalyst.

14. The method of claim 1 wherein the step of comparing the calculated temperature difference with an expected temperature difference comprises obtaining the expected temperature difference from a data library having an expected temperature difference associated with each possible first quantity of fuel.

15. The method of claim 1 wherein the input temp data value being indicative of temperature of fluid at the inlet is obtained by:
measuring a temperature of fluid upstream of the inlet; and
applying a function to the measured temperature value of fluid upstream of the inlet,
wherein said function is dependent on operating parameters and conditions so as to compensate for expected changes in temperature of the fluid between the measured temperature of the fluid upstream of the inlet and an actual temperature of the fluid at the inlet.

16. The method of claim 1 wherein the quantity of fuel to he injected into the exhaust fluid upstream of the inlet for combustion in the diesel oxidation catalyst is injected either:
(a) into at least one cylinder of an engine to which the exhaust fluid treatment apparatus is attached in use; or
(b) through an inlet located downstream of an engine to which the exhaust fluid treatment apparatus is attached in use.

17. The method of claim 16 wherein the injection of the fuels into a cylinder occurs when an exhaust valve of that cylinder is open.

18. An exhaust fluid treatment apparatus comprising a diesel oxidation catalyst and a controller, the diesel oxidation catalyst comprising an inlet and an outlet, the controller configured to:
receive an input temperature data value being indicative of temperature of fluid at the inlet;
initiate a first quantity of fuel to be injected into the exhaust fluid for combustion in the diesel oxidation catalyst;
receive an output temperature data value being indicative of temperature of fluid at the outlet;
calculate a calculated temperature difference between the input temperature data value and the output temperature data value and comparing the calculated temperature difference with an expected temperature difference associated with the quantity of fuel injected; and:
only if the calculated temperature difference is within an acceptable margin of the expected temperature difference, inject a second quantity of fuel into the exhaust fluid for combustion in the diesel oxidation catalyst; and
if the calculated temperature difference is outside the acceptable margin of the expected temperature difference, raise a temperature of exhaust gas upstream of the inlet to the diesel oxidation catalyst.

19. The exhaust fluid treatment apparatus of claim 18 wherein the controller is part of an engine control unit which controls other aspects of engine performance.

20. An engine comprising the exhaust fuel treatment apparatus and the controller of claim 18 .

Assignees

• Perkins Engines Co Ltd

Inventors

• Eager Antony

Classifications

• F01N11/002

  the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus · CPC title

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• B01D2255/00

  Catalysts · CPC title

• F02D41/025

  by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus · CPC title

• F01N3/208

  Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent · CPC title