Adaptive tachometer redline

• US 6,961,667 B1
• Filed: 05/10/2004
• Issued: 11/01/2005
• Est. Priority Date: 05/10/2004
• Status: Expired due to Term

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG)
• Inventors: Wilson, Mark A, Simonich, Mark A
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Walling, Meagan S
• Application Number:
  US10/842,603
• Publication Number:
  US 20050251355A1
• Time in Patent Office: 540 Days
• Field of Search: 702/84, 702/142, 702/141, 702/145, 702/148, 702/147, 324/160, 324/166, 324/169, 324/402, 731/16, 731/181, 734/88, 736/60
• US Class Current: 702/84
• CPC Class Codes: G01P 1/08 Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers
• CPC Class Codes: G01P 1/10 for indicating predetermined speeds
• CPC Class Codes: G07C 7/00 Details or accessories common to the registering or indicating apparatus of groups G07C3/00 and G07C5/00

Abstract

A tachometer system is provided for a motor vehicle having an engine selected from a plurality of engines having unique maximum rated engine RPMs. The system has an RPM data signal and scale correction data. A microcontroller receives the RPM data signal and said scale correction data and generates a scaled tachometer signal therefrom in accordance with a computer program stored in a memory. A gauge drive circuit receives the scaled tachometer signal from the microcontroller. A tachometer gauge has a pointer driven by the gauge driver circuit. The computer program calculates the scaled tachometer signal according to a first scaling constant while the RPM data signal represents less than a predetermined RPM, and calculates the scaled tachometer signal according to a second scaling constant while the RPM data signal represents greater than the predetermined RPM. The second scaling constant is selected from a set of predetermined scaling constants according to the scale correction data.

Claims

1. A tachometer system for a motor vehicle having an engine selected from a plurality of engines having unique maximum rated engine RPMS, the system comprising:

an RPM data signal and scale correction data;

a microcontroller receiving said RPM data signal and said scale correction data and generating a scaled tachometer signal therefrom in accordance with a computer program stored in a memory;

a gauge drive circuit receiving said scaled tachometer signal from said microcontroller; and

a tachometer gauge having a pointer driven by said gauge driver circuit, wherein said computer program calculates said scaled tachometer signal according to a first scaling constant while said RPM data signal represents less than a predetermined RPM, and calculates said scaled tachometer signal according to a second scaling constant while said RPM data signal represents greater than said predetermined RPM, said second scaling constant being selected from a set of predetermined scaling constants according to said scale correction data.

2. The tachometer system of claim 1 wherein said RPM data comprises a network bus message.

3. The tachometer system of claim 1 wherein said RPM data comprises a digital pulse train.

4. The tachometer system of claim 1 wherein said predetermined RPM is less than the lowest maximum rated RPM of the plurality of engines.

5. The tachometer system of claim 1 wherein said tachometer gauge further comprises a dial face having numerated indicia with a highest numbered indicium representing an RPM less than or equal to said predetermined RPM.

6. The tachometer system of claim 1 wherein said scale correction data is a network bus message.

7. The tachometer system of claim 1 wherein said scale correction data resides in said memory.

8. A tachometer system for a motor vehicle having an engine selected from a plurality of engines having unique maximum rated engine RPMs, the system comprising:

an RPM data signal and scale correction data;

a microcontroller receiving said RPM data signal and said scale correction data and generating a scaled tachometer signal therefrom in accordance with a computer program stored in a memory;

a gauge drive circuit receiving said scaled tachometer signal from said microcontroller; and

a tachometer gauge having a dial face with a redline indicium, said tachometer gauge further comprising a pointer driven by said gauge driver circuit, said pointer being rotatable between a zero RPM position and said redline indicium, wherein said computer program calculates said scaled tachometer signal according to a first scaling constant while said RPM data signal represents less than a predetermined RPM, and calculates said scaled tachometer signal according to a second scaling constant while said RPM data signal represents greater than said predetermined RPM, said second scaling constant being selected from a set of predetermined scaling constants according to said scale correction data and the position of said pointer when pointing at said redline indicium.

9. The tachometer system of claim 8 wherein said RPM data comprises a network bus message.

10. The tachometer system of claim 8 wherein said RPM data comprises a digital pulse train.

11. The tachometer system of claim 8 wherein said predetermined RPM is less than the lowest maximum rated RPM of the plurality of engines.

12. The tachometer system of claim 8 wherein said dial face further comprises numerated indicia with a highest numbered indicium representing an RPM less than or equal to said predetermined RPM.

13. The tachometer system of claim 8 wherein said scale correction data is a network bus message.

14. The tachometer system of claim 8 wherein said scale correction data resides in said memory.

15. In a vehicle having an engine RPM data signal and a gauge drive circuit which receives a scaled tachometer signal derived from the RPM data signal, said scaled tachometer signal having a value associated with a redline indicium of a tachometer dial face, a method for deriving the scaled tachometer signal, the method comprising:

determining a maximum rated RPM of an engine in the vehicle;

deriving said scaled tachometer signal according to a first scaling constant while said RPM data signal represents less than a predetermined RPM; and

deriving said scaled tachometer signal according to a second scaling constant while said RPM data signal represents greater than said predetermined RPM, wherein said second scaling constant is predetermined such that the scaled tachometer signal value associated with the redline indicium coincides with the RPM data signal at said maximum rated RPM.

16. The method of claim 15 wherein said step of determining a maximum rated RPM of an engine in the vehicle comprises receiving scale correction data.