Road transportation vehicle drive assist process and apparatus

• US 4,463,427 A
• Filed: 07/30/1981
• Issued: 07/31/1984
• Est. Priority Date: 07/18/1979
• Status: Expired due to Fees

• Current Assignee: Renault Vehicules Industriels
• Original Assignee: Renault Vehicules Industriels
• Inventors: Sibeud, Jean P., Bonnetain, Yves
• Primary Examiner(s): Gruber, Felix D.
• Application Number:
  US06/288,596
• Time in Patent Office: 1,097 Days
• Field of Search: 364/424, 364/424.1, 364/442, 74/866, 340/52 R, 73/114
• US Class Current: 701/123
• CPC Class Codes: F16H 2061/0015 Transmission control for optimising fuel consumptions
• CPC Class Codes: F16H 2061/0096 using a parameter map
• CPC Class Codes: F16H 63/42 Ratio indicator devices
• CPC Class Codes: G01M 15/05 by combined monitoring of two or more different engine parameters
• CPC Class Codes: G07C 5/004 Indicating the operating range of the engine economical driving B60R16/0236, F02B77/084; measuring liquid fuel of an engine G01F9/00

Abstract

The invention pertains to a method and an apparatus, designed to assist the driver of a motor vehicle. The apparatus includes a calculator which is connected to an engine speed sensor, an engine fuel flow sensor, and a transmission speed sensor. The output of the calculator is displayed on an audio/visual display panel. This apparatus defines the operating range of the engine on the load/speed diagram; it also indicates shifting to a different gear, whenever desirable, in order to minimize the vehicle'"'"'s fuel consumption.

Claims

1. A method for assisting the operator of a motor vehicle to minimize the vehicle'"'"'s fuel consumption wherein said vehicle includes an engine connected to a multiple gear ratio transmission, a first sensor generating a current engine speed signal having a value indicative of said engine'"'"'s current speed, a second sensor generating a current ground speed signal having a value indicative of the vehicle'"'"'s current ground speed, a third sensor generating a current fuel flow rate signal having a value indicative of the current fuel flow rate to said engine and a programmed computer having adequate storage and computational means, the method comprising the steps of:

dividing said current ground speed signal by said current engine speed signal to determine the current gear ratio of said transmission;

storing in a load look-up table a plurality of load values, each load value associated with a particular engine speed and fuel flow rate;

addressing said load look-up table with said current engine speed and current fuel flow rate signals to identify a current load value corresponding to the current engine load;

multiplying said current engine speed signal by the ratio between said current gear ratio and the next highest gear ratio of said multiple gear ratio transmission to generate a higher gear ratio engine speed signal corresponding to the engine speed at said next highest gear ratio;

addressing said load look-up table with said higher gear ratio engine speed signal to identify a first set of load values stored with respect to said higher gear ratio engine speed signal;

sequentially addressing said load look-up table with increasing values of fuel flow rate signals to find a first fuel flow rate signal whose value addresses the load value in said first set of load values closest to said current load value;

multiplying said current engine speed signal by the ratio between said current gear ratio and the next lowest gear ratio of said multiple gear ratio transmission to generate a lower gear ratio engine speed signal corresponding to the engine speed at the next lowest gear ratio;

addressing said load look-up table with said lower gear ratio engine speed signal to identify a second set of load values corresponding to said lower gear ratio engine speed;

sequentially addressing said load look-up table with increasing values of fuel flow rate signals to find a second fuel flow rate signal whose value addresses the load value stored in said second set of load values closest to said current load value;

comparing said first and second fuel flow rate signals with said current fuel flow rate signal to generate at least a first change gear signal when said first fuel flow signal is less than said second and current fuel flow rate signals and a second change gear signal when said second fuel flow rate signal is less than said first and current fuel flow rate signals; and

transmitting said first or second change gear signals to an operator perceptible device to generate an operator perceptible signal indicative of the desirability to shift said multiple gear ratio transmission to a gear ratio different from said current gear ratio to minimize the vehicle'"'"'s fuel consumption.

2. The method of claim 1 wherein said operator perceptible device is a visual display, said step of transmitting transmits said first or second change gear signals to said visual display.

3. The method of claim 1 wherein said operator perceptible device is an audio alarm, said step of transmitting transmits said first or second change gear signals to said audio alarm.

4. The method of claim 1 wherein said operator perceptible device comprises a visual display and an audio alarm, said step of transmitting transmits said first or second change gear signals to said visual display and audio alarm.

5. The method of claim 2 wherein said visual display comprises:

at least a first gear shift display indicating the desirability to shift said multiple gear ratio transmission to the next higher gear in response to said first gear change signal; and

at least a second gear shift display indicating the desirability of shifting to the next lower gear ratio in response to said second change gear signal.

6. The method of claim 5 wherein said visual display further comprises an engine speed digital display, a ground speed digital display and a fuel consumption digital display, said method further comprises the steps of:

dividing said current fuel flow rate signal by said current ground speed signal to generate a current fuel consumption signal;

activating said engine speed digital display with said current engine speed signal to display a digital member corresponding to said current engine speed;

activating said ground speed digital display with said current ground speed signal to display a number corresponding to said current ground speed; and

activating said fuel consumption digital display with said current fuel consumption signal to display a number corresponding to the current fuel consumption of the vehicle.

7. The method of claim 6 wherein said visual display further comprises a load/speed diagram display and wherein said load/speed diagram display includes a load/speed diagram having a maximum load curve and a plurality of isometric curves defining areas of equal fuel consumption, and wherein said load/speed diagram display further comprises a matrix of orthogonally disposed light indicators defining a plurality of discrete locations on said load/speed diagram, and wherein one of said plurality of light indicators corresponds to a predetermined engine speed and engine load, said method further comprising activating said one of said plurality of light indicators corresponding to the current engine speed and current engine load in response to said current engine speed signal and said current load signal.

8. The method of claim 6 wherein said first sensor senses a parameter indicative of the rotational period of said engine, said second sensor senses the rotational period of said multiple gear ratio transmission'"'"'s output shaft, and said third sensor senses the fuel flow rate of said engine.

9. The method of claim 8 wherein said step of dividing to determine said current gear ratio further comprises the steps of:

dividing said current ground speed signal by said current engine speed to generate a calculated gear ratio;

comparing said calculated gear ratio to the actual transmission gear ratios stored in an actual gear ratio look-up table to find the actual transmission gear ratio closest to said calculated gear ratio; and

setting said current gear ratio equal to the closest actual transmission gear ratio.

10. The method of claim 9 wherein said visual display further comprises an engine speed digital display, a ground speed digital display, and a fuel consumption digital display, said method further comprising the steps of:

dividing said current fuel flow rate signal by said current ground speed signal to generate a current fuel consumption signal;

activating said engine speed digital display to display the current engine speed in response to said current engine speed signal;

activating said ground speed digital display to display the current ground speed in response to said current ground speed signal; and

activating said fuel consumption digital display to display the current fuel consumption in response to said current fuel consumption signal.

11. The method of claim 9 wherein said first step of addressing further comprises the steps of:

dividing the difference between said current ground speed signal and a predetermined minimum ground speed with a first predetermined constant to generate a first position for a ground speed pointer to said load look-up table;

dividing the difference between the current fuel flow rate signal and a predetermined minimum fuel flow rate by a second predetermined constant to generate a first position for a fuel flow rate pointer to said load look-up table; and

setting said current engine load value equal to the load value stored in said load look-up table corresponding to the position of said ground speed pointer and said fuel flow rate pointer.

12. The method of claim 11 wherein said visual display further comprises an audio alarm, said first or second change gear signals further activates said audio alarm signaling the operator that the gear ratio having the lowest fuel consumption is different from said current gear ratio.

13. The method of claim 12 wherein said visual display further comprises an engine speed digital display, a ground speed digital display and a fuel consumption digital display, said method further comprising the steps of:

dividing said current fuel flow rate signal by said current ground speed signal to generate a current fuel consumption signal;

activating said engine speed digital display to display the current engine speed in response to said current engine speed signal;

activating said ground speed digital display to display the current ground speed in response to said current ground speed signal; and

activating said fuel consumption digital display to display the current fuel consumption in response to said current fuel consumption signal.

14. The method of claim 13 wherein said visual display further comprises a load/speed diagram display and wherein said load/speed diagram display includes a load/speed diagram having a maximum load curve and a plurality of isometric curves defining areas of equal fuel consumption, and wherein said load/speed diagram display further includes means for displaying the coordinate position of the current engine speed and current engine load on said load/speed diagram, said method further comprising the step of activating said means for displaying the coordinate position of the current engine speed and current engine load to display the coordinate position of the current engine speed and current engine load in response to said current engine speed signal and current load value.

15. The method of claim 14 wherein said means for displaying is a matrix of orthogonally disposed light indicators, each light indicator defining a discrete location on said load/speed diagram.

16. The method of claim 2 further comprising the steps of:

dividing said current fuel flow rate signal by said current ground speed signal to generate a current fuel consumption signal; and

transmitting said current fuel consumption signal to said visual display to generate a numerical indication indicative of the vehicle'"'"'s current fuel consumption rate.

17. The method of claim 1 wherein said first sensor senses a parameter indicative of a rotational period of said engine, said second sensor senses the rotational period of said multiple gear ratio transmission'"'"'s output shaft, and said third sensor senses the fuel flow to said engine.

18. The method of claim 17 wherein said step of dividing to determine the current gear ratio comprises the steps of:

dividing said current ground speed signal by said current engine speed signal to generate a calculated gear ratio;

comparing said calculated gear ratio to the actual transmission gear ratios stored in an actual gear ratio look-up table to find the actual transmission gear ratio closest to said calculated gear ratio; and

setting said current gear ratio equal to the closest actual transmission gear ratio.

19. The method of claim 18 wherein said first step of addressing comprises the steps of:

subtracting from the current ground speed signal a predetermined ground speed signal to generate a difference ground speed signal;

dividing said difference ground speed signal by a first predetermined constant to generate a first position of a first pointer pointing to a first coordinate position in said load look-up table;

subtracting from said current fuel flow rate signal a predetermined minimum fuel flow rate signal to generate a difference fuel flow rate signal; and

dividing said difference fuel flow rate signal by a second predetermined constant to generate a first position of a second pointer pointing to a second coordinate position in said load look-up table, the coordinate positions of said first and second pointers identifying a storage location storing a load value corresponding to said current load value.

20. The method of claim 5 wherein said visual display further comprises a third gear shift display indicating said current gear ratio gives the lowest fuel consumption, said step of comparing further comprising the step of generating a no gear change signal indicative of the current gear ratio giving the lowest fuel consumption and said step of transmitting transmits said no gear change signal to said visual display activating said third gear shift display.

21. An apparatus for assisting the operator of a motor vehicle to minimize the vehicle'"'"'s fuel consumption wherein said vehicle includes an engine connected to a multiple gear ratio transmission comprising:

a first sensor responsive to the rotational speed of the engine to generate a current engine speed signal;

a second sensor responsive to the rotational speed of the transmission'"'"'s output shaft for generating a ground speed signal indicative of the vehicle'"'"'s ground speed;

a third sensor responsive to the rate of fuel flow to the engine for generating a current fuel flow rate signal;

means for generating a current gear ratio signal in response to said current engine speed and current ground speed signals;

an engine load look-up table storing a plurality of load values, each load value associated with a particular engine speed and a particular fuel flow rate;

means for addressing said engine load look-up table with said current engine speed and said current fuel flow rate signals to identify a current load value corresponding to the current engine load;

means for multiplying said current engine speed by the ratio between said current gear ratio and the next highest gear ratio of said transmission to generate a higher gear ratio engine speed signal and for multiplying said current engine speed by the ratio between said current gear ratio and the next lower gear ratio of said transmission to generate a lower gear ratio engine speed signal;

means for addressing said load look-up table with said higher gear ratio speed signal and said lower gear ratio signal to identify a first set of load values stored with respect to said higher gear ratio speed signal and a second set of load values stored with respect to said lower gear ratio speed signal respectively;

means for sequentially addressing said load look-up table with increasing values of fuel flow rate signals to find a first fuel flow rate signal whose value addresses the load value in said first set of load values closest to said current load value and find a second fuel flow rate signal whose value addresses the load value in said second set of load values closest to said current load value;

means for comparing said first and second fuel flow rate signals with said current fuel flow rate signal to generate at least a first change gear signal when said first fuel flow rate signal is less than said current and second fuel flow rate signals and a second change gear signal when said second fuel flow rate signal is less than said current and first fuel flow rate signal; and

an operator perceptible device responsive to said first and second change gear signals for generating an operator perceptible signal indicative of the desirability to shift said multiple gear ratio transmission to a gear ratio different from said current gear ratio to minimize the vehicle'"'"'s fuel consumption.

22. The apparatus of claim 21 wherein said operator perceptible device further comprises:

a first visual gear shift display activated by said first change gear signal to indicate the desirability to shift said multiple gear ratio transmission to the next highest gear ratio; and

at least a second visual gear shift display activated by said second change gear signal to indicate the desirability to shift said multiple gear ratio transmission to the next lower gear ratio.

23. The apparatus of claim 22 wherein said operator perceptible device further comprises an audio alarm activated by either of said first or second change gear signals to generate an audible signal alerting the operator of the desirability to shift said multiple gear ratio transmission to a gear ratio different from said current gear ratio.

24. The apparatus of claim 21 wherein said operator perceptible device is an audio alarm activated by either of said first or second change gear signals to generate an audible signal alerting the operator to the desirability to shift said multiple gear ratio transmission to a gear ratio different from said current gear ratio.