Identifying a fuel type

1. A method for determining a type of fuel burned by an engine in a vehicle, the method comprising:

obtaining at least two output parameters of an on board diagnostic (OBD) system of the vehicle;

generating respective estimates of the fuel type based on the at least two output parameters, using a different fuel type identifying method for each respective estimate; and

determining the fuel type based on the respective estimates.

2. The method of claim 1 ,

further comprising assigning a weighting to each of the different fuel type identifying methods, the weighting varying according to the type of fuel identifying method, and

wherein determining the fuel type includes summing the respective estimates with the weightings applied thereto, and comparing the sum of the weightings to a predetermined threshold.

3. The method of claim 1 , further including identifying whether the engine is being throttled based upon at least one of the output parameters, wherein generating the respective estimates of the fuel type includes determining whether the fuel type is gasoline or diesel based on throttling of the engine relative to a threshold throttle level, whereby an indication is provided of a gasoline throttle level that is stronger than a diesel throttle level.

4. The method of claim 3 , wherein identifying whether the engine is being throttled includes detecting whether the engine is being throttled for at least a predefined time period, and

determining that the fuel type is gasoline in response to the engine being throttled for at least the predefined time period, and

determining that the fuel type is diesel in response to the engine being throttled for less than the predefined time period.

5. The method of claim 3 , wherein identifying whether the engine is being throttled includes comparing a manifold absolute pressure (MAP) value indicative of a manifold pressure within the engine with a threshold.

6. The method of claim 3 , wherein identifying whether the engine is being throttled includes comparing air flow through the engine with a threshold corresponding to a predetermined proportion of engine capacity.

7. The method of claim 1 , wherein one of the output parameters is an exhaust gas parameter, and wherein generating the respective estimates of the fuel type includes

estimating that the fuel type is gasoline in response to the exhaust gas parameter falling within a predefined ranged indicative of a gasoline, and

estimating that the fuel type is diesel in response to the exhaust gas parameter falling within a predefined ranged indicative of a diesel.

8. The method of claim 1 , wherein one of the output parameters is fuel pressure, wherein generating the respective estimates of the fuel type includes estimating the fuel type based upon the fuel pressure.

9. The method of claim 1 , wherein

one of the output parameters is idle speed, and

generating the respective estimates of the fuel type includes estimating the fuel type as being diesel in response to the idle speed equalling or exceeding a threshold idling speed, and estimating the fuel type as being gasoline in response to the idle speed being less than the threshold idling speed.

10. The method of claim 9 ,

wherein one of the output parameters is indicative of engine temperature,

further including setting the threshold idling speed based upon the engine temperature.

11. The method of claim 10 , wherein setting the threshold idling speed includes setting the threshold based upon both the engine temperature and the size of the engine.

12. The method of claim 9 , further including setting the threshold idling speed based upon the size of the engine.

13. The method of claim 9 , wherein one of the output parameters is vehicle speed, wherein generating the respective estimates includes using the idle speed in response to the vehicle speed being about zero.

14. An apparatus comprising:

a first circuit module configured and arranged to obtain at least two output parameters of an on board diagnostic (OBD) system of a vehicle having an engine that operates using a type of fuel;

a second circuit module configured and arranged to generate respective estimates of the fuel type based on the at least two output parameters, using a different fuel type identifying method for each respective estimate; and

a third circuit module configured and arranged to determine the fuel type based on the respective estimates.

15. The apparatus of claim 14 , wherein the third circuit module is configured and arranged to

assign a weighting to each of the different fuel type identifying methods, the weighting varying according to the type of fuel identifying method, and

determine the fuel type by summing the respective estimates with the weightings applied thereto, and comparing the sum of the weightings to a predetermined threshold.

16. The apparatus of claim 14 , wherein

the first circuit module includes

an idle speed circuit module configured and arranged to provide an output indicative of idle speed of the engine, and

at least two circuit modules selected from a group of: a temperature circuit module configured and arranged to provide an output based on temperature of the engine, a fuel type circuit module configured and arranged to provide an output based on fuel type used by the engine, an engine size circuit module configured and arranged to provide an output based on size of the engine, and a combination thereof; and

the second circuit module is configured and arranged to provide one of the respective estimates based on the output indicative of idle speed and an adjusted idle speed threshold that is based on a predefined idle speed threshold that is adjusted based on outputs of the at least two circuit modules.

17. The apparatus of claim 14 , wherein the first circuit module includes at least two circuit modules selected from a group of: a temperature circuit module configured and arranged to provide an output based on temperature of the engine, a fuel type circuit module configured and arranged to provide an output based on fuel type used by the engine, an idle speed circuit module configured and arranged to provide an output indicative of idle speed of the engine, an engine size circuit module configured and arranged to provide an output based on size of the engine, and a combination thereof.

18. The apparatus of claim 14 , wherein the second circuit module is configured and arranged to determine whether the engine is being throttled based upon at least one of the output parameters, and to generate the respective estimates of the fuel type by determining whether the fuel type is gasoline or diesel based on throttling of the engine relative to a threshold throttle level and a time period during which the engine is throttled, whereby an indication is provided of a gasoline throttle level that is stronger than a diesel throttle level.

19. A method for determining a fuel type of fuel burned by an engine in a vehicle, the method comprising:

obtaining at least two output parameters of an on board diagnostic (OBD) system of the vehicle, the at least two output parameters being selected from the group consisting of a parameter indicative of whether the engine is being throttled, a parameter indicative of whether exhaust gases exhibit properties in a range corresponding to a particular fuel type, a parameter indicative of fuel pressure, and a combination thereof; and

determining the fuel type based on the at least two output parameters.

20. The method of claim 19 , wherein determining the fuel type includes:

providing a plurality of estimates of the fuel type, each of the plurality of estimates being determined based upon at least one of the output parameters,

assigning a weighting value to each of the plurality of estimates, with different weighting values being assigned to different ones of the estimates based upon the type of each estimate, and

determining the fuel type based upon the plurality of estimates and the weighting values.