Method and apparatus for indicating mileage corresponding to remaining fuel for vehicles

• US 4,400,779 A
• Filed: 04/01/1981
• Issued: 08/23/1983
• Est. Priority Date: 04/03/1980
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation), Toyota Jidosha Kogyo Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Arai, Hiroshi, Ohta, Hisatoshi, Kosuge, Shuichi, Ogura, Hiroshi
• Primary Examiner(s): Smith, Jerry
• Application Number:
  US06/249,877
• Time in Patent Office: 874 Days
• Field of Search: 364/112, 73/113, 73/114
• US Class Current: 701/123
• CPC Class Codes: G01F 9/023 with electric, electro-mechanic or electronic means

Abstract

A method and apparatus for indicating mileage corresponding to remaining fuel for vehicles includes a microprocessor connected to receive input signals respectively indicating a traveled distance and a consumed fuel quantity in a predetermined short period. During such time when quantity of fuel remaining in the tank is above a certain threshold level, the mileage corresponding to the remaining fuel is calculated by multiplying the remaining fuel quantity by a fuel consumption (Km/l) which substantially corresponds to the average fuel consumption during a period between two recent successive fillings of the fuel tank. After the remaining quantity of fuel has reduced below the threshold level, the value of the fuel consumption is updated by increasing the weight of the momentary fuel consumption which reflects the actual running condition. The microprocessor repeatedly calculates the mileage at predetermined intervals and the numerical value of the calculated mileage corresponding to the remaining fuel is displayed on a display unit digitally.

Claims

1. In a method of indicating a mileage corresponding to remaining fuel for a vehicle including the steps of detecting a distance traveled by a vehicle, detecting a quantity of fuel consumed by said vehicle, computing a fuel consumption in accordance with said detected traveled distance and consumed fuel quantity, computing a mileage of said vehicle in accordance with said computed fuel consumption and a quantity of fuel remaining in said vehicle and indicating said computed mileage, the improvement comprising the steps of:

determining whether said remaining fuel quantity is smaller than a predetermined value;

computing said mileage in accordance with a prior average fuel consumption when the result of said determination is negative;

successively updating said average fuel consumption by modifying the same with momentary fuel consumption data obtained at predetermined intervals when the result of said determining step is affirmative, and

computing said mileage in accordance with said updated fuel consumption when the result of said determination is affirmative.

2. A method according to claim 1, wherein said prior average fuel consumption used to compute said mileage, when the result of said determining step is negative, is determined on the basis of an average fuel consumption between two successive fillings of a fuel tank.

3. A method according to claim 1, wherein said step of successively updating said average fuel consumption, when the result of said determining step is affirmative, includes generating a first pulse signal each time a predetermined small distance is traveled by said vehicle and includes generating a second pulse signal each time a predetermined small quantity of fuel is consumed, said average fuel consumption being updated in response to said first and second pulse signals.

4. A method of indicating a mileage corresponding to remaining fuel for a vehicle comprising the steps of:

generating a first pulse signal each time a predetermined small distance is traveled by said vehicle;

generating a second pulse signal each time a predetermined small quantity of fuel is consumed;

integrating, in response to said first and second pulse signals, a total distance traveled and a total quantity of fuel consumed from the previous filling of a fuel tank of said vehicle;

calculating, in response to a signal indicating that the fuel tank has just been filled, a first fuel consumption by a microprocessor by solving a formula as a function of an average fuel consumption during a time period between said previous filling of the fuel tank and the filling at this time, said average fuel consumption being determined by dividing said integrated total distance traveled by said integrated total quantity of fuel consumed;

determining a remaining quantity of fuel in the fuel tank by subtracting from the capacity of the fuel tank a total quantity of fuel consumed obtained by integrating thus far;

determining whether the remaining quantity of fuel is less than a predetermined threshold quantity;

calculating said mileage by multiplying said remaining quantity of fuel by said first fuel consumption, when the remaining quantity of fuel is above said predetermined threshold quantity;

successively executing the following substeps (a) through (c) when the remaining quantity of fuel is less than said predetermined threshold quantity,

(a) integrating a distance and integrating a quantity of fuel in order to calculate a second fuel consumption, said integration of the distance being carried out by sequentially adding said predetermined small distance in response to said first pulse signal to a base distance whose numerical value corresponding to said first fuel consumption, said integration of the quantity of fuel being carried out by sequentially adding said predetermined small quantity of fuel in response to said second pulse signal to a unit quantity of fuel, when said remaining quantity of fuel is less than said predetermined threshold quantity;

(b) calculating a second fuel consumption by dividing the integrated distance of substep (a) by the integrated quantity of fuel of substep (a);

(c) calculating said mileage by multiplying said remaining quantity of fuel by said second fuel consumption;

converting in a display driver coupled to said microprocessor a value indicative of said calculated mileage into a display signal in both cases when the remaining quantity is above said predetermined threshold quantity and less than said predetermined threshold quantity;

displaying on a digital display unit in response to said display signal; and

thereafter

continuously repeating the above sequence of steps at given uniform intervals to effect changes in said displayed possible mileage.

5. A method according to claim 4, wherein when the remaining quantity of fuel is less than said predetermined threshold quantity, there occurs after said step (a), the further substeps of;

(d) determining whether the integrated quantity of fuel is less than a predetermined quantity, and

(e) halving the integrated distance and the integrated quantity of fuel, when the integrated quantity of fuel is more than the predetermined quantity,

whereby in said substep (a) of the next processing cycle, integration of the distance and integration of the quantity of fuel are carried out respectively by adding said predetermined small distance to said halved integrated distance and by adding said small quantity of fuel of said halved integrated quantity of fuel.

6. An apparatus for indicating a mileage corresponding to remaining fuel for a vehicle comprising:

first signal generating means for generating a signal each time a predetermined small distance is traveled by said vehicle;

second signal generating means for generating a signal each time a predetermined small quantity of fuel is consumed;

a full-tank switch operable by a driver of said vehicle to be turned on each time a fuel tank is fully filled;

a microprocessor connected to said first signal generating means, second signal generating means, and said full-tank switch for repeatedly calculating said mileage corresponding to remaining quantity of fuel at predetermined intervals, said microprocessor being adapted to be connected directly to a power source to maintain the same always operable, said microprocessor including,

means for integrating a total distance (D'"'"') and a total quantity of fuel consumed (F'"'"') in response to said first and said second signal generating means, said integrating means being reset each time the fuel tank is filled to the full,

means for calculating a first fuel consumption (E'"'"') from an equation as a function of D'"'"'/F'"'"' and corrected by a factor depending on the type of the vehicle, the D'"'"'/F'"'"' corresponding to an average fuel consumption between the previous filling of the fuel tank and the filling at this time,

means for determining a remaining quantity of fuel by subtracting from the capacity of the fuel tank the total quantity of fuel consumed obtained by said integrating means,

means for determining whether the remaining quantity of fuel is less than a predetermined threshold quantity,

means for calculating said mileage by multiplying said remaining quantity of fuel by said first fuel consumption (E'"'"') obtained by said means for calculating the same, when the remaining quantity of fuel is above said predetermined threshold quantity,

means for integrating a distance (D) and a quantity of fuel (F) respectively, said distance (D) being integrated by sequentially adding said predetermined small distance in response to the signal from said first signal generating means to a base distance whose numerical value corresponding to said first fuel consumption (E'"'"'), said quantity of fuel (F) being integrated by sequentially adding said predetermined small quantity of fuel in response to the signal from said second signal generating means to a unit quantity of fuel (1 l), when said remaining quantity of fuel is less than said predetermined threshold quantity,

means for calculating a second fuel consumption (E) by dividing the integrated distance (D) by the integrated quantity of fuel (F) received from said integrating means, and

means for calculating said mileage by multiplying said remaining quantity of fuel by said second fuel consumption (E);

a display driver connected to said microprocessor for converting a value indicative of said calculated mileage into a display signal; and

a display unit operative in response to the display signal from said display driver for displaying the value of said calculated mileage digitally.