Claims:We claim:
1. A controller (110) to determine temperature of a spark plug seat (106) of an engine (102), said controller (110) adapted to:
receive inputs (108) for a group of parameters related to said engine (102), and
apply said inputs (108) to a thermal model (114) to estimate temperature of said spark plug seat (106).

2. The controller (110) as claimed in claim 1, wherein said group of parameters are selected from an exhaust temperature, an ambient temperature, an engine load, an engine speed, and an engine temperature.

3. A controller (110) to maintain temperature of a spark plug seat (106) of an engine (102), said controller (110) adapted to:
determine a seat temperature, using at least one of a thermal model (114) and a temperature sensor,
compare said seat temperature with a threshold temperature, and
enable fuel enrichment until said temperature comes below said threshold temperature, to maintain said temperature of said spark plug seat (106).

4. The controller (110) as claimed in claim 3, wherein said fuel enrichment is performed through control of a fuel injector (116).

5. The controller (110) as claimed in claim 1 or claim 3, wherein said thermal model (114), and said threshold temperature are stored in a memory element (112) of said controller (110).

6. The controller (110) as claimed in claim 1 or claim 3, wherein said engine (102) is any one of air cooled and liquid cooled.

7. A method for determining temperature of a spark plug seat (106) of an engine (102), the method comprising the steps of:
receiving inputs (108) for a group of parameters related to said engine (102), and
applying said inputs (108) to a thermal model (114) and estimating temperature of said spark plug seat (106).

8. The method as claimed in claim 7, wherein said group of parameters are selected from an exhaust temperature, an ambient temperature, an engine load, an engine speed, and an engine temperature.

9. A method for maintaining temperature of a spark plug seat (106) of an engine (102), said method comprising the steps of:
determining a seat temperature;
comparing said seat temperature with a threshold temperature, and
enabling fuel enrichment until said seat temperature comes below said threshold temperature.

10. The method as claimed in claim 9, wherein said fuel enrichment is performed by controlling fuel injector (116).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present invention relates to a controller and a method to maintain temperature of a spark plug seat.

Background of the invention:
[0002] In air cooled engines, if the temperature of the cylinder head increases beyond a threshold, wear and tear of the engine especially exhaust valve train increases drastically.

[0003] According to a patent literature US2004123588, a method for controlling exhaust gas temperature and space velocity during regeneration to protect temperature sensitive diesel engine components and after-treatment devices is disclosed. A method for controlling the temperature and/or space velocity of exhaust gas provides control of the maximum temperature of the exhaust gas to prevent thermal damage to the Diesel engine components and associated after-treatment devices during regeneration of the after-treatment devices. The method includes controlling intake and/or exhaust valve opening timing and duration, either singly or in combination with selective individual cylinder cutout, in response to sensed engine operating parameters.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0005] Fig. 1 illustrates a block diagram of a controller, according to an embodiment of the present invention, and
[0006] Fig. 2 illustrates a method for maintaining temperature of spark plug seat, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0007] Fig. 1 illustrates a block diagram of a controller, according to an embodiment of the present invention. The Fig. 1 also illustrates an engine 102 fit with a spark plug 104, specifically on a cylinder head of the engine 102. The various components of the engine 102 such as intake valve, exhaust valve, cylinder head, etc. are shown but not explained due to implicit understanding and simplicity. The controller 110 is provided to determine temperature of a spark plug seat 106 in the cylinder head of the engine 102. The controller 110 adapted to receive inputs 108 for a group of parameters related to the engine 102, and apply the inputs 108 to a thermal model 114 to estimate temperature of the spark plug seat 106. The group of parameters are selected from an exhaust temperature, an ambient temperature, an engine load, an engine speed, and an engine temperature. Further, a vehicle speed as a parameter is also usable by the thermal model.

[0008] The controller 110 comprises a processor, memory element 112, timers, clocks and other circuits such as Analog To Digital (ADC) and/or DAC, etc. all connected by communication channel such as Bus. In an embodiment, the controller 110 is an Engine Controller of a vehicle.

[0009] According to another embodiment of the present invention, a controller 110 to maintain temperature of the spark plug seat 106 of the engine 102 is provided. The controller 110 is adapted to determine a seat temperature. The seat temperature is determined using at least one of the thermal model 114 and a temperature sensor. The controller 110 then compares the seat temperature with a threshold temperature, and enables fuel enrichment until the seat temperature comes below the threshold temperature. By this, the controller 110 maintains the temperature of the spark plug seat 106.

[0010] The fuel enrichment is performed through control of a fuel injector 116. The fuel injector 116 is also possible to an e-carburetor. The thermal model 114 and the threshold temperature are stored in the memory element 112 of the controller 110. The engine 102 is an air cooled. Alternatively, the engine 102 is a liquid cooled.

[0011] Fig. 2 illustrates a method for maintaining temperature of spark plug seat of an engine, according to an embodiment of the present invention. The method comprising the steps of, a step 202 comprising, receiving inputs 108 for a group of parameters related to the engine 102. A step 204 comprises, applying the inputs 108 to a thermal model 114 and estimating temperature of the spark plug seat 106. The group of parameters are selected from the exhaust temperature, the ambient temperature, the engine load, the engine speed, and the engine temperature. Further, a vehicle speed as a parameter is also usable by the thermal model. These parameters are either measured with respective sensor or estimated using known values.

[0012] A method for maintaining temperature of a spark plug seat 106 of the engine 102 is provided. The method comprising the steps of determining a seat temperature, either through the step 202 through step 204, or through a temperature sensor. A step 206 comprises, comparing the seat temperature with the threshold temperature. A step 208 comprises enabling fuel enrichment until the seat temperature comes below the threshold temperature or critical limit. The fuel enrichment is performed by controlling fuel injection.

[0013] According to an embodiment of the present invention, the controller 110 increases the durability of air cooled engine 102 by avoiding/preventing the increase in temperature of the spark plug seat 106 beyond a critical limit. Alternatively, the controller 110 is enabled to protect components of the engine 102 such as intake valve, exhaust valve and the like.

[0014] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.