Method for influencing the thermal balance of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9328675-B2
Application number	US-201313754706-A
Country	US
Kind code	B2
Filing date	Jan 30, 2013
Priority date	Feb 2, 2012
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A method for reducing the thermal load of an internal combustion engine without substantially reducing its power output is described. The method includes adjusting an engine air-fuel ratio responsive to one or more of a charge air over-temperature, a coolant over-temperature and an engine efficiency parameter.

First claim

The invention claimed is:

1. A method for influencing a thermal balance of an engine, comprising:
determining a charge air temperature supplied to a cylinder,
adjusting an air-fuel ratio in response to the charge air temperature,
reducing the air-fuel ratio if the charge air temperature exceeds an upper threshold temperature, and
reducing the air-fuel ratio based on a spark efficiency.

2. The method of claim 1 , wherein the air-fuel ratio is reduced by increasing a fuel quantity injected.

3. The method of claim 2 , wherein the air-fuel ratio is reduced from a stoichiometric operation where the air-fuel ratio is substantially equal to 1 to a sub-stoichiometric operation where the air-fuel ratio is less than 1.

4. The method of claim 1 , wherein the charge air temperature is a temperature of aspirated fresh air.

5. The method of claim 1 , wherein the charge air temperature is a temperature of fresh air mixed with recirculated exhaust gas from a return line that branches from an exhaust line and opens into an intake line.

6. The method of claim 1 , wherein the charge air temperature is a temperature of compressed charge air downstream of a compressor from an exhaust gas turbocharger that comprises a turbine arranged in an exhaust line and the compressor arranged in an intake line.

7. The method of claim 6 , wherein a charge air cooler is provided downstream of the compressor, and wherein
the charge air temperature is a temperature of a compressed cooled charge air downstream of the charge air cooler.

8. The method of claim 1 , wherein the engine is liquid-cooled and includes a coolant jacket integrated in a cylinder head, and wherein the coolant jacket is part of a coolant circuit, the method further including:
determining a coolant temperature,
adjusting the air-fuel ratio in response to the coolant temperature, and
reducing the air-fuel ratio if the coolant temperature exceeds an upper threshold.

9. The method of claim 8 , wherein the liquid-cooled engine contains a heat exchanger, and wherein
the coolant temperature is a temperature of coolant downstream of the cylinder head and upstream of the heat exchanger.

10. The method of claim 8 , wherein the air-fuel ratio is reduced when at least one of:
the charge air temperature exceeds the upper threshold temperature for a first threshold time period, and
the coolant temperature exceeds the upper threshold temperature for a second threshold time period.

11. The method of claim 10 , wherein at least one of the charge air temperature and the coolant temperature is determined by calculation.

12. The method of claim 10 , wherein at least one of the charge air temperature and the coolant temperature is determined by a sensor.

13. The method of claim 1 , wherein
the spark efficiency is a ratio relating an efficiency at an ignition timing point to an efficiency at an optimized ignition timing point, and wherein
the air-fuel ratio is reduced when the ratio falls below a threshold.

14. The method of claim 1 , wherein the engine is equipped with an engine control system, and wherein the engine control system stores a map to determine the air-fuel ratio using at least one of the charge air temperature, coolant temperature, and the air-fuel ratio as input values.

15. A method, comprising:
reducing an air-fuel ratio in response to a charge air over-temperature and engine coolant over-temperature, where the ratio is reduced by a first amount responsive to charge air over-temperature and by a second, different amount, responsive to coolant over-temperature, and reducing the ratio by a third amount in response to engine efficiency.

16. The method of claim 15 , wherein the air-fuel ratio is reduced in response to a spark efficiency below a threshold.

17. The method of claim 16 , wherein an amount of air-fuel ratio reduction is based on at least one of:
a degree of charge air over-temperature, a degree of engine coolant over-temperature, and the spark efficiency.

18. The method of claim 15 , wherein the first amount is larger than the second amount during first operating conditions, and wherein the first amount is smaller than the second amount during second operating conditions.

19. A method, comprising:
reducing an air-fuel ratio in response to a charge air over-temperature, engine coolant over-temperature, and an engine spark-related efficiency, where the ratio is reduced by a first amount responsive to charge air over-temperature, by a second, different amount, responsive to coolant over-temperature, and by a third, different amount, responsive to an engine efficiency at a first ignition timing relative to an optimized ignition timing.

Assignees

• Ford Global Tech Llc

Inventors

• Brinkmann Bernd
• Thomas Ben
• Rowland Michael
• Price Gareth

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F02D2200/021

  Engine temperature · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title

• F02D41/00 Primary

  Electrical control of supply of combustible mixture or its constituents (F02D43/00 takes precedence {; control of engine starters F02N11/08, electrical control of engine ignition timing F02P5/145}) · CPC title