Programmable automotive computer system having start time and wheel spin correction

A method for calculating distances traveled associated with driving a vehicle in a test run from a standing start over a selected distance, wherein said method corrects for velocity errors in the data obtained from the onboard diagnostics system (OBD) arising from wheel spin, including the steps of:

• detecting the start time of first movement of vehicle in test run;
• reading velocity values from the OBD;
• time stamping said velocity values using a clock,
• generating a velocity curve from said velocity values and time stamps;
• smoothing said velocity curve so as to determine a point of inflection in the velocity indicative of a termination of wheel spin;
• determining elapsed time from the start time to the inflection point;
• and
• interpolating the velocity values to determine the correct distance from the start time to the inflection point.

A method for determining the time it takes for a vehicle to travel from a standing start to a selected distance, wherein the determination corrects for errors in the velocity values generated by the vehicle's onboard diagnostics system, wherein the errors in the velocity values include errors arising from wheel spin, comprising the steps of:

• detecting the start time of vehicle travel independent of the onboard diagnostics system;
• time stamping each of the velocity values generated by the vehicle's onboard diagnostics system;
• determine an inflection point in the velocity values output by the onboard diagnostics system indicative of the end of the wheel spin state;
• determining the time that the inflection point occurs based on the time stamp of the velocity value at the inflection point;
• generating a velocity curve from the velocity values from the inflection point forward in time;
• integrating the velocity values of the generated velocity curve from the inflection point forward in time to calculate the corrected distance from the inflection point forward;
• interpolating the velocity values from the start time to the inflection point such that the interpolated velocity curve connects to the generated velocity curve at the inflection point;
• and
• integrating the velocity values of the interpolated velocity curve to calculate the corrected distance from the start time to the inflection point.

An electronic portable device for determining the time it takes for a vehicle to travel from a standing start to a selected distance, wherein the device corrects for errors in the velocity values generated by the vehicle's onboard diagnostics system, comprising:

• an input/output port for coupling said device to said diagnostic port for accessing the onboard diagnostic system and the engine computer;
• a detector for detecting the start time of vehicle travel independent of the onboard diagnostics system;
• a microcontroller operative for determining for each velocity value the time period from the start time to when each velocity value is received, for generating a velocity curve from said velocity values;
• and for integrating the velocity values to calculate the time of travel from the start time to the selected distance;
• a memory for providing storage in said device for velocity values received from the onboard diagnostics system and providing storage in said device, for each velocity value, the time period from the start time to when each velocity value is received;
• and
• a touch screen display for enabling user control of device operations.