DE2824741A1 - DEVICE FOR CONTINUOUS MEASUREMENT AND DISPLAY OF FUEL CONSUMPTION OF A MOTOR VEHICLE - Google Patents

Description

Device for continuous measurement and display of the fuel consumption of a motor vehicle

The invention relates to devices for measuring and displaying distance traveled Fuel consumption of a vehicle.

These devices are intended to provide the driver with information so that he can set up his driving style so that he can get out of his Vehicle gets the best performance with the lowest consumption.

All of these devices are based on the principle of establishing the ratio of the flow rate (measured in liters per hour, for example) of the fuel consumed to the speed of the vehicle. If you want to measure the fuel consumption of a vehicle in relation to a distance traveled, you have to establish the ratio ^ at every point in time, where D is the flow rate (measured in liters per hour, for example) and V is the speed of the vehicle. In order to obtain the consumption expressed in liters per 100 km, the ratio «6 ^ must be calculated, where oL · is a coefficient that depends on the choice of units. To implement this principle, the following are required: - Means for measuring the flow rate (for example measured in liters per hour) of the fuel, the

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are arranged to provide electrical signals, which are proportional to the flow rate (e.g. measured in liters per hour)

Means for measuring the speed of the vehicle, also arranged to receive electrical signals which are representative of this speed

- Means for evaluating the electrical quantities that the both parameters flow rate and velocity are assigned, these means serving to provide a to deliver an electrical signal that is proportional to the quotient of these two parameters.

- Finally, a meter that measures the amount of fuel provides a value based on the distance covered, which then appears on a reading device.

The amalgamation of these funds in the mainly known devices has never before become a competitive one Cost price are realized, which explains that they are not sold in the trade. Indeed, the realization of these devices requires the assembly of a large number of particularly expensive ones Components.

The present invention is based on the object of specifying a simple and reliable device which has a relatively low cost price and which at any given point in time the exact value of the ratio between the flow rate of the consumed fuel and the vehicle speed.

To solve this problem, according to the invention, a as Divider serving circuitry used to represent the flow rate and velocity

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electrical values to / work out. This circuit is therefore constructed from a photosensitive element that receives an illuminance that is produced by a light source with linear variation (e.g. an electroluminescent diode) or by a light source with non-linear Variation (e.g. of an incandescent lamp) is caused.

The invention is explained below with reference to the drawings. Show it:
1 shows an embodiment of a divider circuit,

which uses a linear light source; 2 shows a basic diagram of the entire device

a divider circuit.

The light source used according to FIG. 1 consists of an LED diode 1 which is fed by a current i. That The main feature of such a diode is that it produces an illuminance that is equal to that of the Current that feeds it is proportional. This current is supplied to her by a sensor that measures the speed of the vehicle by converting it into a proportional current.

This diode 1 illuminates a photo-resistor 2 with a hyperbolic function, of which the linear range is selected at £ ~ Ä A , where f is the characteristic coefficient of the photo-resistor and is specified by the manufacturer. This photo resistor 2 is traversed by a current I, which is generated by the sensor which measures the flow rate, and so there is a potential difference U at the terminals of the photo resistor, which is the ratio between flow rate and

Speed.

The principle of operation of this device can be mathematically as follows are set out:

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It is assumed that the sensors intended for measuring D (flow rate) and V (vehicle speed) convert these quantities into proportional currents: i = k ₁ V and I = k ₂ D.

The illuminance caused by diode 1 is:

I ¹ _ V η. - Γ. 1 1

The resistance of the element 2 is below this Conditions on:

K K

2 2

R = - or - if γ = 1,

Ε ^γ Ε

from what

R = _i_ = ^ ₁

K ₁ II

K KkD

that means ^u = JL I = _2 _2_ Ki KkV 1 11

"α - (where« t is the equivalent of the four given Coefficient is).

The voltage appearing at the terminals of the photo resistor 2 therefore reflects the ratio -.

Using the same procedure, it is possible to take roots or raise them to the power of n ^e (where η does not necessarily have to be an integer) if y, which is equal to 1 in the example chosen, assumes different values.

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Choosing a light source with non-linear variation can also expand the possibilities of this device, which ^ in general can always be used when a ratio or a product of two functions has to be measured either analog or digital.

However, in the case of using a non-linear light source, a logarithmic function is obtained, whereas a simple division is obtained in the example described above.

Fig. 2 shows a basic diagram of the device as a whole with a divider circle according to the invention. This divider circuit 3 is connected to two amplifiers 4a (flow rate amplifiers) and 4b (speed amplifier) connected. These amplifiers have two probes 5a (sensor for the flow rate and 5b (sensor for the velocity) connected, which the The flow rate of the fuel and the vehicle speed represented quantities in electrical measurements convert. The divider circuit 3 belongs to a measuring device 6 (for example with a digital display), the one Shows a value expressed, for example, in liters per 100 km.

The main advantage of the divider circle 3 is that it can continuously create the ratio rr at any time. Any fluctuation in flow rate or velocity is immediately reported to the reader; in fact the response time is practically zero.

This same circle can also be used for locomotion of a vehicle equipped with an electric motor Measure the energy consumed. This measurement can be expressed in amps per kilometer.

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L e r s e ι

Claims (3)

Claims 1J device for the continuous measurement and display of the flow rate of a motor vehicle or the energy consumption of a vehicle with an electric motor, based on a distance traveled, with means that the
Vehicle speed and flow rate
measure and convert them into electrical quantities, with means for evaluating these quantities, which are representative of the relationship between the flow rate of the consumed fuel and the vehicle speed
Generate voltage and with a measuring instrument (6), the
provides a value that is, for example, in liters per
100 km is expressed and that on a display device
appears, characterized in that the above-mentioned means for evaluation have a divider circuit (3) which consists of a light-sensitive element (2) through which a current flows, the strength of which is the
Flow rate of fuel is proportional, and
which (2) is illuminated by a light source (1), which in turn is supplied by a current that is one of the
Speed of the vehicle causes proportional light intensity. 2. Apparatus according to claim 1, characterized in that the light sensitive element (2) by a light source (1) with linear variation, for example by 809886/08 1 8 an electroluminescent diode, is illuminated. 3. Apparatus according to claim 1, characterized in that the photosensitive element (2) aurch a light source (1) is illuminated with non-linear variation, for example by an incandescent lamp. 809886/06 1 8