초록 ▼

A device and corresponding method for enabling a user to accurately control, monitor, and evaluate performance of a vehicle. A portable programmable computer device that a user can readily plug into a diagnostic connector port of the vehicle for providing the controlling, monitoring, and evaluating

A device and corresponding method for enabling a user to accurately control, monitor, and evaluate performance of a vehicle. A portable programmable computer device that a user can readily plug into a diagnostic connector port of the vehicle for providing the controlling, monitoring, and evaluating functions. Accurate detection of the start time of first movement of the vehicle is made based on data from an accelerometer, independent of the onboard diagnostic system and its diagnostics port. A clock is started for measuring time such that the precise time taken to reach the time-stamped first velocity value from the engine computer via the diagnostic port is determined. Data from the accelerometer and diagnostic port is analyzed and selectively used for accurately and reliably correcting for errors in velocity data from the onboard diagnostic system including latency error and errors due to the vehicle exhibiting wheel spin.

대표청구항 ▼

What is claimed is: 1. A method for calculating a point at which a vehicle has traveled a selected distance from a standing start point, wherein the distance calculation corrects for errors in velocity data available from a vehicle's onboard diagnostics system, comprising: accessing the onboard dia

What is claimed is: 1. A method for calculating a point at which a vehicle has traveled a selected distance from a standing start point, wherein the distance calculation corrects for errors in velocity data available from a vehicle's onboard diagnostics system, comprising: accessing the onboard diagnostic system to obtain said vehicle velocity data; detecting the start time of said vehicle travel, wherein said detector is independent of said onboard diagnostic system; detecting vehicle acceleration; generating a first set of velocity values based on said detected vehicle start time and said detected vehicle acceleration; storing said first set of velocity values; storing a second set of velocity values based on the vehicle velocity data received from said onboard diagnostic system; generating a time stamp for each of said velocity values of said first set and said second set; generating corrected velocity values as a function of said first set and said second set of velocity values, said time stamps, and said detected start time; and integrating said corrected velocity values to calculate the point at which the vehicle has traveled the selected distance from said standing start point. 2. The method of claim 1, further comprising: determining a second time corresponding to the time when the vehicle has reached the selected distance; and calculating the time it took for the vehicle to travel the selected distance from said standing start point, including subtracting the start time from said second time. 3. The method of claim 1, wherein said start time is detected as a function of first movement of said vehicle. 4. The method of claim 1, wherein the errors include errors resulting from vehicle wheel spin. 5. The method of claim 1, wherein the errors include errors caused by the distance said vehicle travels before the first velocity value is generated by the vehicle's onboard diagnostics system. 6. The method of claim 1, further comprising accessing the engine computer. 7. The method of claim 1, wherein an accelerometer is used for detecting the start time of vehicle travel and for detecting vehicle acceleration. 8. The method of claim 7, wherein said accelerometer is triggered by movement of said vehicle and has an output that is a function of said triggering and indicates the magnitude thereof. 9. The method of claim 8, wherein the step of detecting the start time of said vehicle travel further comprises: sampling said output of said accelerometer; and determining the start time of said vehicle travel by the sampled output reaching a predetermined magnitude for a predetermined number of samples. 10. The method of claim 7, wherein the step of generating a first set of velocity values comprises: reading raw X, Y, and Z axis values of said accelerometer from an AID converter, wherein said A/D converter has a timebase; and storing said axis values according to said timebase. 11. The method of claim 7, wherein the step of generating corrected velocity values comprises generating the corrected velocity values for the time period between the detected start time of vehicle travel to the vehicle's rollout distance based on data acquired from the accelerometer and not based on values received from said onboard diagnostic system; wherein the rollout distance is the distance of one complete revolution of the vehicle's tires. 12. The method of claim 11, wherein the step of generating corrected velocity values further comprises: for distances beyond the vehicle's rollout distance, generating the corrected velocity values based only on values received from said onboard diagnostic system and not based on data acquired from the accelerometer unless the error between velocity values received from said onboard diagnostic system and velocity values based on data acquired from the accelerometer exceeds a predetermined threshold indicative of wheel spin. 13. The method of claim 12, further comprising: when the error between velocity values is indicative of wheel spin, generating the corrected velocity values based solely on data acquired from said accelerometer unless the difference between the velocity values based on data acquired from the accelerometer and the velocity values received from said onboard diagnostic system is below a predetermined number, and when the difference is below the predetermined number, generating velocity values solely from velocity values received from said onboard diagnostic system. 14. The method of claim 7, wherein said step of generating said first set of velocity values further comprises: determining that said vehicle has been staged; sampling acceleration values for each axis of said accelerometer for a predetermined number of samples while said vehicle is staged; averaging the sampled acceleration values over a predetermined time while the vehicle is staged, and storing zero values for each axis of said accelerometer as a function of said averaged data samples so as to correct for errors in the alignment of said accelerometer. 15. The method of claim 1, wherein said step of generating corrected velocity values further comprises aligning in time said second set of velocity values with said first set of velocity values. 16. The method of claim 15, wherein said aligning in time comprises: interpolating said time stamped second set of velocity values in said time stamped first set of velocity values such that each velocity value of said second set is associated with a time stamp of said first set; and storing said interpolated second set of velocity values along with the corresponding time stamp from the corresponding velocity value of said first set. 17. The method of claim 1, further comprising calculating and displaying the times to reach one or more predetermined speeds as a function of at least one of said corrected velocity values. 18. The method of claim 2, further comprising calculating and displaying the times to reach one or more predetermined distances as a function of at least one of said corrected velocity values; wherein said predetermined distances are less than said selected distance. 19. The method of claim 1, further comprising calculating and displaying engine horsepower as a function of at least one of said corrected velocity values. 20. The method of claim 1, further comprising calculating and displaying engine torque as a function of at least one of said corrected velocity values. 21. An electronic portable device for calculating a point at which a vehicle has traveled a selected distance from a standing start point, wherein the distance calculation corrects for errors in velocity data available from a vehicle's onboard diagnostics system, comprising: an input/output port for coupling said device to said diagnostic port for accessing the onboard diagnostic system to obtain said vehicle velocity data; a detector for detecting vehicle movement and the start time of said vehicle travel, wherein said detector is independent of the onboard diagnostics system; a microcontroller operative for generating a first set of velocity values and a corresponding time stamp for each velocity value of said first set based on data acquired by said detector, for receiving a second set of velocity values generated by said onboard diagnostic system via said input/output port and for generating a time stamp for each of said velocity values of said second set, for generating corrected velocity values as a function of said first set and said second set of velocity values, said time stamps, and said detected start time, and for integrating said corrected velocity values to calculate the point at which the vehicle has traveled the selected distance from said standing start point; and a memory for providing storage in said device for said first set of velocity values, for said second set of values based on the vehicle velocity data received from said onboard diagnostic system, and for said time stamps. 22. The device of claim 21, wherein said corresponding time stamp for each velocity value of said first set is a function of the time period from said detected start time to when the corresponding data for each velocity value of said first set was acquired by said detector. 23. The device of claim 21, wherein said time stamp for each velocity value of said second set is indicative of the time period from said detected start time to when each velocity value of said second set was received. 24. The device of claim 21, wherein said microcontroller is also operative for determining a second time corresponding to the time when the vehicle has reached the selected distance; and for calculating the time it took for the vehicle to travel the selected distance from said standing start point, including subtracting the start time from said second time. 25. The device of claim 21, wherein said detector includes an accelerometer that generates acceleration values as a function of movement of said vehicle and a touch screen display for enabling user selection of device operations. 26. A method for calculating a point at which a vehicle has traveled a selected distance from a standing start point, wherein the distance calculation corrects for errors in the velocity data available from a vehicle's onboard diagnostics system, comprising accessing the onboard diagnostic system to obtain said vehicle velocity data; detecting the start time of said vehicle travel and the vehicle's acceleration using an accelerometer, wherein said accelerometer is independent of said onboard diagnostic system; in a first time interval from the start time to the time taken to reach the first velocity value received from said onboard diagnostic system, generating corrected velocity values based on data acquired from said accelerometer; thereafter, generating corrected velocity values based on velocity data from said onboard diagnostics system if said velocity data does not significantly vary from said velocity values generated based on data acquired from said accelerometer, otherwise, generating corrected velocity values based on data acquired from said accelerometer; and integrating said corrected velocity values to calculate the point at which the vehicle has traveled the selected distance from said standing start point. 27. The method of claim 26, further comprising: determining a second time corresponding to the time when the vehicle has reached the selected distance; and calculating the time it took for the vehicle to travel the selected distance from said standing start point, including subtracting the start time from said second time. 28. The method of claim 26, wherein the errors corrected for include errors resulting from vehicle wheel spin. 29. The method of claim 26, wherein the errors corrected for include errors caused by the distance said vehicle travels before the first velocity value is generated by the vehicle's onboard diagnostics system.