Characterizing engine load

1. A method comprising:

obtaining a plurality of engine load values for an engine in a vehicle based on outputs provided by an on board diagnostic (OBD) system of the vehicle, each of the load values being obtained using an algorithm that is different than an algorithm used for obtaining other ones of the load values;

processing the plurality of engine load values by maximizing differences between the engine load values;

identifying an engine load reporting strategy used by the OBD system based on the respective differences; and

generating an output characterizing operation of the engine based on the identified engine load reporting strategy.

2. The method of claim 1 ,

further including obtaining an engine speed of the vehicle while the engine load values are obtained, and

wherein identifying the engine load reporting strategy includes comparing respective ones of the respective engine load values with an engine load threshold associated with the speed of the engine at the time that the engine load values were obtained.

3. The method of claim 2 , wherein the engine load threshold pertains to an engine load when the engine is idling, and wherein identifying the engine load reporting strategy includes identifying the engine load reporting strategy in response to the engine load values being below the engine load threshold.

4. The method of claim 1 , wherein generating the output includes estimating a force provided to cranks of the vehicle using an empirically derived relationship between force and size of the engine.

5. The method of claim 1 , further including using outputs provided by the OBD system to determine when the engine is idling, wherein obtaining the plurality of engine load values includes obtaining the values in response to determining that the engine is idling.

6. The method of claim 1 , wherein obtaining the plurality of engine load values includes obtaining the engine load values during one or more time periods during which the engine is idling.

7. The method of claim 1 , wherein maximizing differences between the engine load values includes determining maximum differences between the engine load values under different operating conditions of the engine, and wherein the engine load reporting strategy is identified based on the respective differences under operating conditions of the engine at which different ones of the respective load values exhibit maximum differences.

8. The method of claim 1 , wherein obtaining the plurality of engine load values includes obtaining the engine load values when the engine is idling.

9. The method of claim 8 , further including determining that the engine is idling based on a threshold engine idling speed, wherein obtaining the plurality of engine load values includes obtaining the engine load values in response to determining that the engine is at or below the threshold engine idling speed.

10. The method of claim 9 , further including setting the threshold engine idling speed based on one or more parameters selected from the group consisting of: an amount of time that the engine has been running, engine temperature, engine capacity, vehicle speed, and a fuel type used by the engine.

11. The method of claim 1 ,

further including determining whether the vehicle is held in a stationary state by engagement of a clutch plate, and

wherein obtaining the plurality of engine load values includes obtaining the engine load values in response to determining that the vehicle is held in the stationary state.

12. The method of claim 1 , wherein generating the output includes estimating a crank force provided to a crank of the engine using an empirically derived relationship between crank force and engine size, and generating the output based on the crank force.

13. The method of claim 1 , wherein

each algorithm pertains to an engine load reporting strategy,

obtaining the plurality of engine load values for the engine in the vehicle includes, for each obtained load value, executing one of the algorithms pertaining to the engine load reporting strategies while concurrently executing the other ones of the algorithms to pertain the other ones of the plurality of engine load values, and

identifying the engine load reporting strategy includes inferring the engine load reporting strategy being used by a vehicle management system within the vehicle, based on the outputs provided by the OBD system and obtained through an OBD port connection in the vehicle.

14. The method of claim 13 , wherein inferring the engine load reporting strategy includes identifying the engine load reporting strategy without directly accessing the vehicle management system.

15. The method of claim 1 , wherein obtaining the plurality of engine load values includes inferring an engine load value not provided via the OBD system, based on outputs that are provided via the OBD system.

16. The method of claim 1 , wherein obtaining the plurality of engine load values includes obtaining all of the engine load values while the vehicle operates within a range of a common set of operating conditions.

17. The method of claim 1 , wherein obtaining the plurality of engine load values includes obtaining the values from an OBD port of the OBD system, independently from outputs provided by an engine management system of the vehicle.

18. The method of claim 17 , wherein obtaining the plurality of engine load values includes estimating one of the engine load values based on the outputs provided by the OBD system that are different than the estimated one of the engine load values.

19. The method of claim 17 , wherein obtaining the plurality of engine load values includes estimating at least one of the engine load values for information blocked from access by the vehicle's engine management system.

20. A method comprising:

coupling a computer circuit to an on board diagnostic (OBD) port of a vehicle's OBD system; and

in the computer circuit,

determining respective load values for an engine in the vehicle utilizing respective engine load reporting algorithms, based on output parameters obtained from the OBD system, while operating the engine under operating conditions of the engine that maximize differences between the determined load values; and

identifying one of the engine load reporting algorithms as being used by the OBD system based on the differences between the load values, and utilizing the identified one of the engine load reporting algorithms with diagnostic data obtained from the OBD port to generate an output characterizing real-time operation of the engine.