# US 2014/0196701 A1 · Method for operating an exhaust gas recirculation system

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- Number: US 2014/0196701 A1
- Document ID: US20140196701A1
- Status: Published application
- Kind: A1
- Application number: 14/153,672
- Filed: 2014-01-13
- Published: 2014-07-17
- Earliest claimed: 2013-01-11
- Assignees: GM Global Technology Operations LLC
- Applicants: GM Global Technology Operations LLC
- Inventors: Boris STOJKOVIC; Domenico RAMPONE; Paolo PAGANO; Paolo PASERO
- Web page: https://patentgrep.com/patent/US20140196701A1

## CPC

- F02M 26/28: with liquid-cooled heat exchangers
- F01P 3/20: Cooling circuits not specific to a single part of engine or machine (F01P3/22 takes precedence)
- F02M 26/25: with coolers having bypasses
- F02M 26/33: controlling the temperature of the recirculated gases
- F02M 26/47: the characteristics being temperatures, pressures or flow rates
- F01P 2060/16: Outlet manifold
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28)

## Abstract

A method is provided for operating an Exhaust Gas Recirculation (EGR) system of a thermal energy source, the EGR system includes, but is not limited to an EGR circuit and an EGR cooler, the EGR cooler connected in a heat exchanging relationship with an EGR coolant circuit equipped with an EGR coolant pump. The method includes, but is not limited to monitoring a parameter (TEGRcool) representative of a temperature of the coolant in the EGR coolant circuit, operating the EGR coolant pump on the basis of the parameter (TEGRcool) and of a target value thereof (TEGRtgt).

## Claims

### Claim 1

A method of operating an Exhaust Gas Recirculation (EGR) system of a thermal energy source, the EGR system comprising an EGR circuit and an EGR cooler, the EGR cooler being connected in an heat exchanging relationship with an EGR coolant circuit that is equipped with an EGR coolant pump, the method comprising the steps of:
monitoring a parameter (TEGRcool) representative of a temperature of the coolant in the EGR coolant circuit; and
operating the EGR coolant pump on the basis of the parameter (TEGRcool) and of a target value thereof (TEGRtgt).

### Claim 2 (depends on 1)

A method according to claim 1, further comprising:
activating for a predetermined activation time (tON) the EGR coolant pump if the monitored value of the parameter (TEGRcool) is higher than the target value (TEGRtgt); and
deactivating for a predetermined deactivation time (tOFF) the EGR coolant pump.

### Claim 3 (depends on 1)

A method according to claim 1, wherein the activation state of the EGR coolant pump is adjusted with a closed-loop control strategy that uses as feedback the parameter value (TEGRcool) to minimize a difference between the parameter value (TEGRcool) and the target value (TEGRtgt).

### Claim 4 (depends on 1)

A method according to claim 1, further comprising:
monitoring a parameter (THLoad) representative of a thermal load of the thermal energy source; and
bypassing the EGR cooler if the parameter (THLoad) is lower than a first target value thereof (THCutoff) representative of low thermal load conditions.

### Claim 5 (depends on 2)

A method according to claim 2, further comprising:
repeating the activation and deactivation steps of the EGR coolant pump if the parameter (THLoad) representative of a thermal load of the thermal energy source is higher than the first target value thereof (THCutoff) and lower than a second target value thereof (THWarmup) representative of the end of a warm up phase of the thermal energy source.

### Claim 6 (depends on 2)

A method according to claim 2, wherein the thermal energy source is an internal combustion engine.

### Claim 7 (depends on 6)

A method according to claim 6, wherein the predetermined values of the activation time (tON) and of the deactivation time (tOFF) of the EGR coolant pump are determined with an empirically determined map correlating different values of the activation time (tON) and of the deactivation time (tOFF) to different values of engine speed, engine load, engine temperature, EGR gas flow in the EGR circuit, environmental temperature, and pressure.

### Claim 8 (depends on 6)

A method according to claim 6, wherein the parameter (THLoad) indicative of a thermal load is a function of engine temperature, engine speed, and engine torque.

### Claim 9

An Exhaust Gas Recirculation (EGR) system of a thermal energy source, comprising:
an EGR circuit; and
an EGR cooler, connected in heat exchanging relationship with an EGR coolant circuit equipped with an EGR coolant pump,
wherein the EGR circuit and the EGR coolant circuit have portions which are adjacent to each other to form heat exchange area for the exhaust gas.

### Claim 10

An apparatus for operating an Exhaust Gas Recirculation (EGR) system of an internal combustion engine, the EGR system comprising an EGR circuit and an EGR cooler, the EGR cooler being connected in a heat exchanging relationship with an EGR coolant circuit equipped with an EGR coolant pump, the apparatus comprising:
a monitor that is configured to monitor a parameter (TEGRcool) representative of a temperature of the coolant in the EGR coolant circuit;
an operating device that is configured to operate the EGR coolant pump on the basis of the parameter (TEGRcool) and of a target value thereof (TEGRtgt).

### Claim 11 (depends on 10)

An apparatus according to claim 10, wherein the monitory comprises a coolant temperature sensor.

### Claim at position 12

12-15. (canceled)