Method for controlling exhaust gas heat recovery systems in vehicles

• US 8,463,495 B2
• Filed: 12/01/2010
• Issued: 06/11/2013
• Est. Priority Date: 12/01/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Spohn, Brian L., Claypole, George M., Starr, Richard D
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): MELTON, TODD M
• Application Number:
  US12/957,755
• Publication Number:
  US 20120143437A1
• Time in Patent Office: 923 Days
• Field of Search: 701/36
• US Class Current: 701/36
• CPC Class Codes: F01M 5/001 Heating
• CPC Class Codes: F01N 2240/02 a heat exchanger
• CPC Class Codes: F01N 5/02 the devices using heat
• CPC Class Codes: F01P 2060/045 for transmissions
• CPC Class Codes: F01P 2060/16 Outlet manifold
• CPC Class Codes: F16H 57/0413 Controlled cooling or heating of lubricant; Temperature control therefor
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

Claims

1. A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission, and a transmission radiator, the method comprising:

controlling a two-way valve, wherein the two-way valve is configured to be set to one of an engine position and a transmission position, wherein the engine position allows heat-exchange communication between the EGHR heat exchanger and the engine and does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger, and the transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine;

monitoring an ambient air temperature;

comparing the monitored ambient air temperature to a predetermined cold ambient temperature;

if the monitored ambient air temperature is greater than the predetermined cold ambient temperature, setting the two-way valve to the transmission position;

controlling a transmission thermostat, wherein the transmission thermostat is configured to be set to one of an EGHR position and a radiator position, wherein the EGHR position allows heat-exchange communication between the transmission and the oil-to-water heat exchanger, and the radiator position allows heat-exchange communication between the transmission and the transmission radiator and blocks heat-exchange communication between the transmission and the oil-to-water heat exchanger, and wherein the transmission thermostat has three ports;

an inlet port in fluid-flow communication with an oil outlet of the transmission,

a first outlet port in fluid-flow communication with the oil-to-water heat exchanger, and

a second outlet port in fluid-flow communication with the transmission radiator, wherein the EGHR position allows fluid-flow communication between the inlet port and the first outlet port and the radiator position allows fluid-flow communication between the inlet port and the second outlet port;

monitoring a transmission oil temperature;

comparing the monitored transmission oil temperature to a transmission thermostat temperature;

if the monitored transmission oil temperature is above the transmission thermostat temperature, setting the transmission thermostat to the radiator position;

controlling an engine thermostat, wherein the engine thermostat is configured to be set to one of an open position and a closed position, wherein the open position allows heat-exchange communication between the engine and the engine radiator and the closed position blocks heat-exchange communication between the engine and the engine radiator;

monitoring an engine water temperature;

comparing the monitored engine water temperature to an engine thermostat temperature;

if the monitored engine water temperature is above the engine thermostat temperature, setting the engine thermostat to the open position;

wherein controlling the two-way valve includes providing an engine signal configured to place the two-way valve into the engine position;

wherein the transmission thermostat temperature is within five degrees Celsius of the engine thermostat temperature;

if the monitored ambient air temperature is below the predetermined cold ambient temperature, comparing the monitored engine water temperature to an engine target temperature;

if the monitored engine water temperature is below the engine target temperature, setting the two-way valve to the engine position;

if the monitored engine water temperature is above the engine target temperature, monitoring for an auto-stop mode, wherein the auto-stop mode occurs when the engine is not producing positive torque; and

if the engine is not in the auto-stop mode, setting the two-way valve to the transmission position.

2. The method of claim 1, further comprising:

if the engine is in the auto-stop mode, comparing the monitored transmission oil temperature to a transmission target temperature;

if the monitored transmission oil temperature is above the transmission target temperature, setting the two-way valve to the engine position; and

if the monitored transmission oil temperature is below the transmission target temperature, setting the two-way valve to the transmission position.

3. The method of claim 2, wherein the two-way valve is set to the transmission position whenever the engine signal is not provided, such that the two-way valve is configured to default to the transmission position when unpowered.

4. A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission, the method comprising:

controlling a two-way valve, wherein the two-way valve is configured to be set to one of an engine position and a transmission position in response to an engine signal which is configured to place the two-way valve into the engine position, wherein the engine position allows heat-exchange communication between the EGHR heat exchanger and the engine and does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger, and the transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine;

monitoring an ambient air temperature;

comparing the monitored ambient air temperature to a predetermined cold ambient temperature; and

if the monitored ambient air temperature is greater than the predetermined cold ambient temperature, setting the two-way valve to the transmission position, wherein the two-way valve is set to the transmission position whenever the engine signal is not provided, such that the two-way valve is configured to default to the transmission position when unpowered; and

if the monitored ambient air temperature is below the predetermined cold ambient temperature, comparing the monitored engine water temperature to an engine target temperature;

if the monitored engine water temperature is below the engine target temperature, setting the two-way valve to the engine position, and

if the monitored engine water temperature is above the engine target temperature, monitoring for an auto-stop mode, wherein the auto-stop mode occurs when the engine is not producing positive torque;

if the engine is not in the auto-stop mode, setting the two-way valve to the transmission position, and

if the engine is in the auto-stop mode, comparing the monitored transmission oil temperature to a transmission target temperature;

if the monitored transmission oil temperature is above the transmission target temperature, setting the two-way valve to the engine position, and

if the monitored transmission oil temperature is below the transmission target temperature, setting the two-way valve to the transmission position.

5. The method of claim 4, wherein the vehicle further includes a transmission radiator, and further comprising:

controlling a transmission thermostat, wherein the transmission thermostat is configured to be set to one of an EGHR position and a radiator position, wherein the EGHR position allows heat-exchange communication between the transmission and the oil-to-water heat exchanger, and the radiator position allows heat-exchange communication between the transmission and the transmission radiator and blocks heat-exchange communication between the transmission and the oil-to-water heat exchanger;

monitoring a transmission oil temperature;

comparing the monitored transmission oil temperature to a transmission thermostat temperature; and

if the monitored transmission oil temperature is above the transmission thermostat temperature, setting the transmission thermostat to the radiator position.

6. The method of claim 5,

wherein the transmission thermostat has three ports:

an inlet port in fluid-flow communication with an oil outlet of the transmission,

a first outlet port in fluid-flow communication with the oil-to-water heat exchanger, and

a second outlet port in fluid-flow communication with the transmission radiator; and

wherein the EGHR position allows fluid-flow communication between the inlet port and the first outlet port and the radiator position allows fluid-flow communication between the inlet port and the second outlet port.

7. The method of claim 6,

wherein the transmission thermostat has three ports:

an inlet port in fluid-flow communication with the oil-to-water heat exchanger and an oil outlet of the transmission,

a first outlet port in fluid-flow communication with the transmission, and

a second outlet port in fluid-flow communication with the transmission radiator; and

wherein the EGHR position allows fluid-flow communication between the inlet port and the first outlet port and the radiator position allows fluid-flow communication between the inlet port and the second outlet port.

8. The method of claim 7, wherein the transmission thermostat temperature is within five degrees Celsius of the engine thermostat temperature.