# US 7,406,822 B2 · Particulate trap regeneration system and control strategy

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- Number: US 7,406,822 B2
- Document ID: US7406822B2
- Status: Granted
- Kind: B2
- Application number: 11/169,750
- Filed: 2005-06-30
- Published: 2007-01-04
- Granted: 2008-08-05
- Earliest claimed: 2005-06-30
- Assignees: Caterpillar Inc.
- Inventors: Steven J. Funke; Jason K. Bloms; Andrew A. Knitt; Chandini A. M. Ammineni; Michael P. Withrow
- Web page: https://patentgrep.com/patent/US7406822B2

## CPC

- F01N 9/002: {of filter regeneration}
- F01N 3/025: using fuel burner or by adding fuel to exhaust
- F01N 2900/0422: measuring the elapsed time
- Y02T 10/40: Engine management systems
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A particulate trap regeneration system is provided. The system may include a particulate trap configured to remove one or more types of particulate matter from an exhaust flow of an engine. The system may also include a regeneration device configured to reduce an amount of particulate matter in the particulate trap. The system may further include a controller configured to activate the regeneration device in response to the first to occur of at least three trigger conditions.

## Claims

### Claim 1

A particulate trap regeneration system, comprising:
a particulate trap configured to remove one or more types of particulate matter from an exhaust flow of an engine;
a regeneration device configured to reduce an amount of particulate matter in the particulate trap; and
a controller configured to activate the regeneration device in response to the first to occur of at least three trigger conditions;
wherein each of the at least three trigger conditions is associated with a separate, individual operating parameter of the regeneration system;
wherein each individual operating parameter is indicative of an amount of particulate matter in the particulate trap and is associated with a separate, individual, predetermined threshold; and
wherein, for each of the at least three trigger conditions, the respective trigger condition exists when the respective individual operating parameter that is associated with the respective trigger condition is at, or beyond, the predetermined threshold associated with the respective individual operating parameter.

### Claim 2 (depends on 1)

The system of claim 1, wherein the at least three trigger conditions are selected from the group consisting of operation of the engine for a predetermined amount of time; consumption of a predetermined amount of fuel by the engine; detection of an elevated backpressure upstream of the particulate trap above a predetermined pressure; detection of a pressure differential across the particulate trap of greater than a predetermined amount; determination that a calculated amount of particulate matter accumulated in the particulate trap is above a predetermined amount; and activation of a manual trigger.

### Claim 3 (depends on 1)

The system of claim 1, wherein the activation of the regeneration device is further conditional on one or more engine operating parameters.

### Claim 4 (depends on 3)

The system of claim 3, wherein the one or more engine operating parameters include at least one of engine speed and engine load.

### Claim 5 (depends on 1)

The system of claim 1, wherein the regeneration device is configured to elevate a temperature of the particulate trap.

### Claim 6 (depends on 5)

The system of claim 5, further including:
an upstream temperature sensor configured to measure a first temperature of the exhaust flow upstream from the particulate trap; and
a downstream temperature sensor configured to measure a second temperature of the exhaust flow downstream from the particulate trap;
wherein the controller is configured to compare the first temperature with the second temperature and generate a fault code if the second temperature exceeds the first temperature by more than a predetermined amount.

### Claim 7 (depends on 6)

The system of claim 6, wherein the controller is configured to illuminate a warning light and prevent future regeneration attempts if the fault code is generated more than a predetermined number of times.

### Claim 8 (depends on 5)

The system of claim 5, wherein the regeneration device includes a burner assembly having a fuel injector and being configured to create a flame, which is in a heat exchange relationship with the exhaust flow.

### Claim 9 (depends on 8)

The system of claim 8, further including:
a flame sensing system associated with the burner assembly and configured to detect whether the flame is lit;
wherein the flame sensing system includes at least one of the following:
a flame sensor selected from the group consisting of a temperature sensor and an ion sensor, wherein the flame sensing system is configured to measure at least one of:
a condition in proximity to the flame; and
a rate of change of a condition in proximity to the flame; and
an upstream temperature sensor configured to measure an upstream exhaust temperature upstream of the burner assembly and a downstream temperature sensor configured to measure a downstream exhaust temperature downstream of the burner assembly, the flame sensing system being configured to determine whether the downstream exhaust temperature exceeds the upstream exhaust temperature by a predetermined amount.

### Claim 10 (depends on 8)

The system of claim 8, wherein the system is further configured to flush the fuel injector with fresh air at one or more of the following times to clear the fuel injector of any debris or unburned fuel:
prior to ignition of the flame; and
subsequent to the flame being extinguished.

### Claim 11 (depends on 8)

The system of claim 8, wherein the system is further configured to cool the fuel injector while the flame is not lit.

### Claim 12 (depends on 8)

The system of claim 8, wherein the system is further configured to supply air to the fuel injector to be mixed with fuel for combustion in the burner assembly, and wherein the source of the air is the air intake system of the engine downstream from a compressor configured to create forced induction for the engine.

### Claim 13 (depends on 8)

The system of claim 8, wherein the system is further configured to operate an ignition source at various times during operation of the system, including after the flame has been extinguished, to ignite fuel delivered to the burner by the fuel injector and to ignite any unburned fuel in the fuel injector after the flame has been extinguished.

### Claim 14 (depends on 8)

The system of claim 8, wherein the system is further configured to regulate pressure of fuel supplied to the fuel injector via a closed loop feedback system.

### Claim 15 (depends on 8)

The system of claim 8, wherein the system is further configured to operate in a pilot mode, wherein the fuel injector delivers a predetermined mixture of air and fuel to the burner assembly under various engine operating conditions, to prevent the flame from being extinguished.

### Claim 16 (depends on 5)

The system of claim 5, wherein the regeneration device is configured to increase the temperature of the exhaust flow upstream from the particulate trap, the system further including an upstream temperature sensor configured to measure an upstream temperature of the exhaust flow upstream from the particulate trap;
the controller being further configured to control the regeneration device to thereby regulate the upstream temperature, in a closed loop fashion, based on the upstream temperature measured by the upstream temperature sensor.

### Claim 17 (depends on 16)

The system of claim 16, wherein the regeneration device includes a burner assembly configured to create a flame and a fuel injector configured to deliver fuel to the burner assembly, the system being configured to:
regulate the upstream temperature by regulating an amount of fuel supplied to the fuel injector; and
regulate a ratio of air to fuel supplied to the fuel injector.

### Claim 18

A method of regenerating a particulate trap, comprising:
monitoring three individual aspects of an exhaust flow producing engine and an exhaust system configured to carry exhaust produced by the engine away from the engine, each of the three individual aspects being indicative of an amount of particulate matter in the particulate trap;
wherein each of the three individual aspects is associated with a separate, individual, predetermined threshold, and
wherein, for each of the three individual aspects, a respective trigger condition exists when the respective individual aspect is at, or beyond, the respective predetermined threshold that is associated with the respective individual aspect; and
activating a regeneration device configured to reduce an amount of particulate matter in a particulate trap configured to remove one or more types of particulate matter from the exhaust flow of the engine, in response to at least one of the three individual aspects being determined to meet the respective trigger condition associated therewith.

### Claim 19 (depends on 18)

The method of claim 18, wherein the trigger conditions are selected from the group consisting of operation of the engine for a predetermined amount of time; consumption of a predetermined amount of fuel by the engine; detection of an elevated backpressure upstream of the particulate trap above a predetermined pressure; detection of a pressure differential across the particulate trap of greater than a predetermined amount; determination that a calculated amount of particulate matter accumulated in the particulate trap is above a predetermined amount; and activation of a manual trigger.

### Claim 20 (depends on 18)

The method of claim 18, wherein the activating of the regeneration device is further conditional on one or more operating parameters of the engine.

### Claim 21 (depends on 20)

The method of claim 20, wherein the one or more operating parameters include at least one of engine speed and engine load.

### Claim 22 (depends on 18)

The method of claim 18, wherein the regenerating includes increasing a temperature of the particulate trap.

### Claim 23 (depends on 22)

The method of claim 22, further including creating a flame with a burner assembly having a fuel injector, the flame being in a heat exchange relationship with the exhaust flow.

### Claim 24 (depends on 23)

The method of claim 23, further including:
detecting whether the flame is lit with a flame sensing system associated with the burner assembly;
wherein the detecting includes monitoring at least one of the following:
a temperature in proximity to the flame
an amount of ions in proximity to the flame
a rate of change of the temperature in proximity to the flame;
a rate of change of the amount of ions in proximity to the flame; and
a difference in temperature between an upstream exhaust temperature upstream of the burner assembly and a downstream exhaust temperature downstream of the burner assembly, wherein monitoring the difference in temperature includes determining whether the downstream exhaust temperature exceeds the upstream exhaust temperature by a predetermined amount.

### Claim 25 (depends on 23)

The method of claim 23, further comprising cooling the fuel injector while the flame is not lit.

### Claim 26 (depends on 23)

The method of claim 23, further including supplying air to the fuel injector and mixing the air with fuel for combustion in the burner assembly, wherein the source of the air is the air intake system of the engine downstream from a compressor configured to create forced induction for the engine.

### Claim 27 (depends on 23)

The method of claim 23, further including regulating pressure of fuel supplied to the fuel injector via a closed loop feedback system.

### Claim 28 (depends on 22)

The method of claim 22, further including:
increasing the temperature of the exhaust flow upstream from the particulate trap;
measuring an upstream temperature of the exhaust flow upstream from the particulate trap; and
controlling the regeneration device to thereby regulate the upstream temperature, in a closed loop fashion, based on the upstream temperature.

### Claim 29 (depends on 28)

The method of claim 28, wherein the regeneration device includes a burner assembly configured to create a flame and a fuel injector configured to deliver fuel to the burner assembly, the method further including:
regulating the upstream temperature by regulating an amount of fuel supplied to the fuel injector; and
regulating a ratio of air to fuel supplied to the fuel injector.

### Claim 30

A method of regenerating a particulate trap, comprising:
monitoring three aspects of an exhaust flow producing engine and an exhaust system configured to carry exhaust produced by the engine away from the engine;
increasing a temperature of the particulate trap by activating a regeneration device configured to reduce an amount of particulate matter in a particulate trap configured to remove one or more types of particulate matter from the exhaust flow of the engine, in response to at least one of the three aspects being determined to meet a trigger condition;
measuring an upstream temperature of the exhaust flow upstream from the particulate trap;
measuring a downstream temperature of the exhaust flow downstream from the particulate trap;
comparing the upstream temperature with the downstream temperature and generating a fault code if the downstream temperature exceeds the upstream temperature by more than a predetermined amount; and
preventing future regeneration attempts and illuminating a warning light if the fault code is generated more than a predetermined number of times.

### Claim 31

A method of regenerating a particulate trap, comprising:
monitoring three aspects of an exhaust flow producing engine and an exhaust system configured to carry exhaust produced by the engine away from the engine;
activating a regeneration device configured to reduce an amount of particulate matter in a particulate trap configured to remove one or more types of particulate matter from the exhaust flow of the engine, in response to at least one of the three aspects being determined to meet a trigger condition;
wherein the regenerating includes increasing a temperature of the particulate trap by creating a flame with a burner assembly having a fuel injector, the flame being in a heat exchange relationship with the exhaust flow; and
flushing the fuel injector with fresh air at one or more of the following times to clear the fuel injector of any debris or unburned fuel:
prior to ignition of the flame; and
subsequent to the flame being extinguished.

### Claim 32

A method of regenerating a particulate trap, comprising:
monitoring three aspects of an exhaust flow producing engine and an exhaust system configured to carry exhaust produced by the engine away from the engine;
activating a regeneration device configured to reduce as amount of particulate matter in a particulate trap configured to remove one or more types of particulate matter from the exhaust flow of the engine, in response to at least one of the three aspects being determined to meet a trigger condition;
wherein the regenerating includes increasing a temperature of the particulate trap by creating a flame with a burner assembly having a fuel injector, the flame being in a heat exchange relationship with the exhaust flow; and
operating an ignition source at various times during operation of the system, including after the flame has been extinguished, to ignite fuel delivered to the burner assembly by the fuel injector and to ignite any unburned fuel in the fuel injector after the flame has been extinguished.

### Claim 33

A machine, comprising:
an exhaust flow producing engine;
a particulate trap configured to remove particulate matter from the exhaust flow produced by the engine;
a pressure differential measurement system configured to measure a pressure differential between an upstream pressure of the exhaust flow upstream from the particulate trap and a downstream pressure of the exhaust flow downstream from the particulate trap;
a particulate loading monitor configured to determine an amount of particulate matter that has accumulated in the particulate trap;
a regeneration device configured to reduce the amount of particulate matter in the particulate trap; and
a controller configured to:
determine, by a comparison of an individual operating parameter to a predetermined threshold, whether each of the following trigger conditions has occurred:
the engine has been operated for a predetermined amount of time;
the pressure differential exceeds a predetermined pressure differential; and
the amount of particulate matter determined, by the particulate loading monitor, to have accumulated in the particulate trap exceeds a predetermined amount; and
activate the regeneration device in response to the first to occur of the three trigger conditions.

### Claim 34 (depends on 33)

The machine of claim 33, wherein the activation of the regeneration device is further conditional on one or more operating parameters of the engine, the one or more operating parameters including at least one of engine speed and engine load.

### Claim 35 (depends on 33)

The machine of claim 33, wherein the regeneration device is configured to elevate a temperature of the particulate trap, the machine further including:
an upstream temperature sensor configured to measure an upstream temperature of the exhaust flow upstream from the particulate trap; and
a downstream temperature sensor configured to measure a downstream temperature of the exhaust flow downstream from the particulate trap;
wherein the controller is configured to compare the upstream temperature with the downstream temperature and generate a fault code if the downstream temperature exceeds the upstream temperature by more than a predetermined amount;
the controller being further configured to prevent future regeneration attempts and illuminate a warning light if the fault code is generated more than a predetermined number of times.

### Claim 36 (depends on 33)

The machine of claim 33, wherein the regeneration device is configured to elevate a temperature of the particulate trap and includes a burner assembly having a fuel injector;
the regeneration device being further configured to create a flame, which is in a heat exchange relationship with the exhaust flow.

### Claim 37 (depends on 36)

The machine of claim 36, wherein the machine is further configured to flush the fuel injector with fresh air prior to ignition of the flame to clear the fuel injector of any debris and flush the fuel injector with fresh air subsequent to the flame being extinguished to clear the fuel injector of any debris and unburned fuel.

### Claim 38 (depends on 36)

The machine of claim 36, wherein the machine is further configured to cool the fuel injector while the flame is not lit.

### Claim 39 (depends on 36)

The machine of claim 36, wherein the machine is configured to supply air to the fuel injector to be mixed with fuel for combustion in the burner assembly, wherein the source of the air is the air intake system of the engine downstream from a compressor configured to create forced induction for the engine.

### Claim 40 (depends on 36)

The machine of claim 36, wherein the regeneration device includes a burner assembly configured to increase the temperature of the exhaust flow upstream from the particulate trap by creating a flame and a fuel injector configured to deliver fuel to the burner assembly, the system further including an upstream temperature sensor configured to measure an upstream temperature of the exhaust flow upstream from the particulate trap;
the controller being further configured to control the regeneration device to thereby regulate the temperature of the exhaust flow upstream from the particulate trap, in a closed loop fashion, based on the upstream temperature measured by the upstream temperature sensor by regulating an amount of fuel supplied to the fuel injector and a ratio of air to fuel supplied to the fuel injector.

### Claim 41 (depends on 36)

The machine of claim 36, wherein the regeneration is conditional on ground speed such that regeneration is prevented if the machine has a ground speed of below a predetermined speed for more than a predetermined amount of time; and
wherein the regeneration is conditional on which gear a transmission of the machine is operating in, such that regeneration is prevented if the transmission is in neutral.

### Claim 42 (depends on 36)

The machine of claim 36, wherein the regeneration is conditional on engagement of a parking brake of the machine such that regeneration is prevented if the parking brake is engaged.

### Claim 43 (depends on 36)

The machine of claim 36, further including:
a flame sensing system associated with the burner assembly and configured to detect whether the flame is lit;
wherein the flame sensing system includes at least one of the following:
a flame sensor selected from the group consisting of a temperature sensor and an ion sensor, wherein the flame sensing system is configured to measure at least one of:
a condition in proximity to the flame; and
a rate of change of a condition in proximity to the flame; and
an upstream temperature sensor configured to measure an upstream exhaust temperature upstream of the burner assembly and a downstream temperature sensor configured to measure a downstream exhaust temperature downstream of the burner assembly, the flame sensing system being configured to determine whether the downstream exhaust temperature exceeds the upstream exhaust temperature by a predetermined amount.