Method for controlling engine temperature of an engine
A method for controlling engine temperature of an engine with a wide dynamic range is disclosed. In one example, the derivative of an engine temperature is assessed by a controller. The controller may adjust engine actuators to limit engine temperature in response to the derivative.
1. A method for controlling an engine, comprising:
when engine temperature is less than a first threshold, limiting an engine temperature rate of change to be less than a first amount; and
when said engine temperature exceeds the first threshold, limiting the engine temperature rate of change to be less than a second amount, said second amount less than said first amount.
2. The method of claim 1 wherein said limiting engine temperature rate of change includes reducing an amount of boost provided to said engine.
3. The method of claim 1 wherein said limiting engine temperature rate of change includes limiting a spark angle at which spark is supplied to at least one cylinder of said engine.
4. The method of claim 2 wherein said amount of boost is limited by a waste gate.
5. The method of claim 1 wherein said limiting engine temperature rate of change includes controlling a position of a throttle plate of said engine.
6. The method of claim 1 wherein said limiting engine temperature rate of change includes adjusting a type and quantity of fuel delivered to said engine.
7. A method for controlling an engine, comprising:
adjusting an engine control parameter such that a rate of temperature change of said engine is less that a first amount when a temperature of said engine is less than a first threshold temperature; and
adjusting the engine control parameter such that said rate of temperature change of said engine is less than a second amount, said second amount less than said first amount, when a temperature of said engine is greater than a second threshold temperature.
8. The method of claim 7 wherein said control parameter is a desired amount of boost.
9. The method of claim 7 wherein said control parameter is a cylinder air amount.
10. The method of claim 7 wherein said control parameter is an angle of a camshaft relative to a position of a crankshaft.
11. The method of claim 7 further comprising varying said second amount with the temperature of said engine.
12. The method of claim 7 further comprising limiting shifting of a transmission when said temperature of said engine is greater than said second threshold temperature.
13. The method of claim 12 wherein said limiting inhibits said transmission from downshifting when a resultant speed of said engine exceeds a threshold.
14. The method of claim 7 further comprising enriching an air-fuel mixture of at least one cylinder of said engine when said temperature of said engine is greater than said second threshold temperature and engine load exceeds a threshold.