# US 10,480,441 B2 · System and method for controlling exhaust gas temperature

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- Number: US 10,480,441 B2
- Document ID: US10480441B2
- Status: Granted
- Kind: B2
- Application number: 15/873,972
- Filed: 2018-01-18
- Published: 2018-05-31
- Granted: 2019-11-19
- Earliest claimed: 2015-07-22
- Assignees: Cummins Inc.
- Applicants: Cummins Inc.
- Inventors: John L. Hoehne; Ian W. McGiffen; Chandan Mahato; Paul Daniel Borisuk; Boopathi Singalandapuram Mahadevan
- Web page: https://patentgrep.com/patent/US10480441B2

## CPC

- F02D 41/1446: {the characteristics being exhaust temperatures}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 11/002: {the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus}
- F02B 29/0406: {Layout of the intake air cooling or coolant circuit}
- F02B 37/186: {Arrangements of actuators or linkage for bypass valves}
- F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)}
- F02D 41/0245: {by increasing temperature of the exhaust gas leaving the engine}
- F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
- F01N 2430/00: Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
- F01N 2900/1404: Exhaust gas temperature
- F01N 2900/1406: Exhaust gas pressure
- F01N 2900/1602: Temperature of exhaust gas apparatus
- F02B 37/00: Engines characterised by provision of pumps driven at least for part of the time by exhaust
- F02D 2200/0406: Intake manifold pressure
- F02D 2200/0802: Temperature of the exhaust gas treatment apparatus
- F02D 2250/36: Control for minimising NOx emissions
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/40: Engine management systems
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- 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)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A system and method for controlling a temperature of an exhaust gas at an inlet of a selective catalytic reduction system during at least certain low air density conditions. The system may detect an air density value upstream of an internal combustion engine of an engine system, such as, for example, at an inlet of a compressor. Using the detected air density, one of a plurality of relationships between an engine speed and an outputted engine power, as a function of the detected air density value, may be selected for use in determining what combination of engine speed(s) and/or engine power(s) will produce an exhaust gas that is within a target exhaust gas temperature. Using the selected relationship, at least one of the engine speed and the engine power may be adjusted to at least assist in attaining the target exhaust gas temperature.

## Claims

### Claim 1

A method comprising:
detecting an air density value upstream of an internal combustion engine of an engine system;
modifying a relationship between an engine speed and an outputted engine power as a function of the detected air density value; and
adjusting, using the modified relationship between an engine speed and an outputted engine power of the internal combustion engine, at least one of the engine speed and the outputted engine power to attain a target exhaust gas temperature along at least a portion of an after-treatment system of the engine system.

### Claim 2 (depends on 1)

The method of claim 1, wherein the air density value is detected at an inlet of a compressor, and wherein the target exhaust gas temperature is a target temperature for an exhaust gas at an inlet of a selective catalytic reduction system of the after-treatment system.

### Claim 3 (depends on 2)

The method of claim 2, wherein the target temperature is between around 300 degrees Celsius to around 450 degrees Celsius.

### Claim 4 (depends on 3)

The method of claim 3, wherein the step of adjusting at least one of the engine speed and the outputted engine power comprises adjusting the engine speed of the internal combustion engine while maintaining the outputted engine power.

### Claim 5 (depends on 3)

The method of claim 3, wherein the step of adjusting at least one of the engine speed and the outputted engine power comprises adjusting the outputted engine power while maintaining the engine speed.

### Claim 6 (depends on 5)

The method of claim 5, wherein the step of adjusting the outputted engine power comprises adjusting a torque outputted by operation of the internal combustion engine.

### Claim 7 (depends on 5)

The method of claim 5, wherein the step of adjusting the outputted engine power comprises adjusting at least one of a current level and a voltage level outputted by operation of the internal combustion engine.

### Claim 8 (depends on 2)

The method of claim 2, wherein the target temperature is a temperature that protects the after-treatment system from damage due to excessive exhaust gas temperature, and further wherein the target temperature does not exceed 525 degrees Celsius.

### Claim 9

A method comprising:
determining an air density value for an inlet of an air compressor, the air compressor positioned at an inlet side of an internal combustion engine of an engine system;
identifying, from two or more ranges of air density values, a range of air density values that encompasses the determined air density value;
selecting, using the identified range of air density values, an engine speed and engine power relationship from a plurality of engine speed and engine power relationships, the selected engine speed and engine power relationship corresponding to an engine speed and an engine power to be achieved by operation of the internal combustion engine to attain a target exhaust gas temperature; and
attaining the target exhaust gas temperature by at least adjusting at least one of the engine speed and the engine power using information from the selected engine speed and engine power relationship.

### Claim 10 (depends on 9)

The method of claim 9, wherein the step of attaining the target exhaust gas temperature does not include reducing a target engine out nitrogen oxide level by timing retardation or lowering of fuel injection pressures.

### Claim 11 (depends on 9)

The method of claim 9, wherein the target exhaust gas temperature is a target temperature of an exhaust gas at an inlet of a selective catalytic reduction system of the engine system.

### Claim 12 (depends on 11)

The method of claim 11, wherein the target temperature is between around 300 degrees Celsius to around 450 degrees Celsius.

### Claim 13 (depends on 11)

The method of claim 11, wherein the step of attaining the target exhaust gas temperature by at least adjusting at least one of the engine speed and the engine power comprises adjusting the engine speed while maintaining the engine power.

### Claim 14 (depends on 3)

The method of claim 3, wherein the step of attaining the target exhaust gas temperature by at least adjusting at least one of the engine speed and the engine power comprises adjusting the engine power while maintaining the engine speed, and wherein the adjusted engine power comprises at least one of the following, a torque, a current level, and a voltage level outputted by operation of the internal combustion engine.

### Claim 15 (depends on 9)

The method of claim 9, wherein the target exhaust gas temperature is a temperature that protects an after-treatment system from damage due to excessive exhaust gas temperatures, and further wherein the target exhaust gas temperature does not exceed 525 degrees Celsius.

### Claim 16

A method comprising:
determining an air-fuel ratio for an engine of an engine system;
modifying a relationship between an engine speed and an outputted engine power as a function of the determined air-fuel ratio; and
adjusting at least one of the engine speed and the outputted engine power using the modified relationship between the engine speed and the outputted engine power to attain a target exhaust gas temperature at an inlet of a selective catalytic reduction system of the engine system.

### Claim 17 (depends on 16)

The method of claim 16, further including the step of determining the air-fuel ratio includes determining an air density value at an inlet of a compressor positioned upstream of the engine, and wherein the air-fuel ratio is determined, at least in part, using the detected air density value.

### Claim 18 (depends on 17)

The method of claim 17, wherein the target exhaust gas temperature is between around 300 degrees Celsius to around 450 degrees Celsius.

### Claim 19 (depends on 18)

The method of claim 18, wherein the step of adjusting at least one of the engine speed and the outputted engine power comprises adjusting the engine speed while maintaining the outputted engine power.

### Claim 20 (depends on 17)

The method of claim 17, wherein the adjusted outputted engine power comprises at least one of the following, a torque, a current level, and a voltage level outputted by operation of the internal combustion engine.