GB2052744A

GB2052744A - Combined speed and fuel consumption indicating device

Info

Publication number: GB2052744A
Application number: GB8017148A
Authority: GB
Original assignee: Pierburg GmbH
Current assignee: Pierburg GmbH
Priority date: 1979-05-31
Filing date: 1980-05-23
Publication date: 1981-01-28
Also published as: ES249682U; SE8003799L; DE2922172A1; FR2458056A1; JPS5626220A; IT8048296A0; ES249682Y

Abstract

The invention provides a device and a process for indicating, at each instant, the rate of fuel consumption of an internal combustion engine in a motor vehicle, which is characterised in that the rate of fuel consumption is displayed simultaneously with the engine or the vehicle speed on a common dial. Speed may be indicated by a pointer moving over a circular scale, by a mechanically driven moving column or by a lit up number display. Fuel consumption rate may be indicated by a pointer moving over a scale concentric with the scale for the speed pointer or over a circular scale adjacent the speed scale on a common dial, or by the change of colour of the lit up number of the lit up speed display. Alternatively deviations from optimum driving behaviour can be indicated by a row of electronic light emitting elements. An audible warning of excessive fuel consumption rate may be given.

Description

SPECIFICATION Fuel consumption indicating device The invention relates to a process and device for indicating, at each instant, the rate of fuel consumption of an internal combustion engine, particularly in a motor vehicle.

The purpose in giving the driver of a motor vehicle an indication of his fuel consumption is to enable him to optimise his manner of driving with a view to eonomising fuel. For the indication to be useful he must be able to make repeated observations at short intervals of time of his speed of travel (km/hour), his change of speed and his distance-based fuel consumption (litres/100 km), with minimal degradation of his driving attention.

Only by observing all these quantities repeatedly and at short intervals can he form an appreciation of their interrelationships and so optimise his driving behaviour with a view to minimising fuel consumption.

What is required is therefore that the driver should be enabled to observe these quantities each time as rapidly as possible, at a single glance, so that he can repeat the observations frequently without this distracting his attention excessively.

Many different processes and devices of this kind are known, but they all have the disadvantage that the fuel consumption indicator is spaced away, on the dashboard of the car, from the speedometer so that a comparatively long time is required to read both of them. Examples are described in the Frankfurter Allgemeine Zeitung of the 6 December 1978, in the motoring section, and in VDO-lnformationsheft "Kraftstoffverbrauchsanzeige", page 7, in Figure 5. A further disadvantage of the known devices is that they merely show absolute values, without providing an easy visual correlation between fuel consumption and the speed of travel of the vehicle.

The intention in the present invention is therefore to provide a simple process of the kind described at the beginning, but which enables the driver to read vehicle speed and fuel consumption simultaneously. A further intention is to arrange the display so that the driver can easily evaluate at each instant the relationship between the two quantities.

The problem is solved, according to the invention, in that the rate of fuel consumption at each instant is displayed on the dial of a speedometer.

The present invention will now be described in greater detail on the basis of the examples shown in Figures 1 to 5 of the drawings, in which: Figure 1 is a diagram; Figure 2 is a front view of an indicator; Figure 3 is a side view; Figures 4 and 5 show two variants.

In all the figures the same reference numbers are used for corresponding parts.

In the diagram of Figure 1 a motor vehicle is assumed to be travelling at varying speeds on a level road. Distance-based fuel consumption KV, litres/100 km, is measured on the ordinate. True road speed Left, km/hour, is measured on the abscissa of the graph. The continuous curve represents the speed VT, km/hour, indicated by the speedometer. Distance-based fuel consumption KV, litres/100 km, is represented by the chain line.

The curves are positioned on the graph so as to bring them over each other. If the chain line, representing fuel consumption, is followed from the left towards the right it will be seen that at low speeds fuel consumption increases only slowly with increasing speed. Then, in the middle range of the chain-line curve, fuel consumption increases proportionately with increase in speed. Finally, at high speeds fuel consumption increases much more rapidly than speed.

The idea in the present invention is, in the first place, to display distance-based fuel consumption KV on the dial of the speedometer of the vehicle.

Secondly, the intention is to arrange the scale showing fuel consumption KV in such a way that with changing vehicle speed the changing relationship between the two quantities, speed and fuel consumption, is displayed with convincing clarity to the driver. Figure 2 shows a first example of the invention.

Figure 2 shows, at 1, the dial of a speedometer.

The speedometer needle, or pointer, is shown at 2.

A shorter fuel-consumption pointer 3 pivots about the same centre as the speedometer pointer 2.

The speed scale 4 extends around the periphery of the dial from zero, at the left, to 200 km/h at the right. The fuel consumption scale 5, of smaller diameter, extends from zero, on the left, to 20 1/100 km at the right. Alternatively the speed scale can, of course, if desired be the inner one and the fuel-consumption scale the outer one.

It will be observed in Figure 2 that the two zero marks are radially in line with each other, and the 20 1/100 km mark is radially in line with the 200 km/h mark. This agrees conveniently with the fact that, in the case of most motor cars on the road today, irrespective of size, when the car is travelling at ordinary cruising speeds, anywhere between 70 and 130 km/h, fuel consumption measured in litres per 100 km is approximately 1/10th of speed, measured in km/h, or a little less.

For example at 100 km/h the fuel consumption, with the car running on a level road, is usually in the region of 10 1/100 km, or a little less, irrespective of the size of the car. Consequently, as suggested in Figure 2, over the middle speed range the consumption pointer substantially follows the speed pointer, but usually remaining a little to the left of it, the two pointers swinging together back and forth. On the other hand, when speed is increased to above the usual range the consumption pointer hurries forwards, overtaking the speed pointer, to a position far ahead of it, as indicated in broken lines in Figure 2. An analogous effect is obtained when the car slows right down.

With rotation of the speed pointer anti-clockwise, down towards a very low speed, the consumption pointer lags behind, adopting a position clockwise to the right of the speed pointer. At two intermediate speeds, a fairly low one and a fairly high one, the pointers coincide.

In Figure 2 the speed pointer is shown at 100 km/h. The consumption pointer indicates 9 1/100 km. Between the two pointers there is an angle of-delta. This small angle informs the driver that he is cruising economically. Suppose now that he gradually increases his speed. The consumption pointer soon catches up and, with further speed increase, swings over the right of the speed pointer, warning the driver that his manner of driving has become uneconomical. Analogous information is conveyed to the driver under other driving conditions, for example when running up a hill. Thus under all driving conditions the driver is warned when he begins driving uneconomically.

The facts conveyed agree with the diagram of Figure 1.

In particular, when the driver stamps his pedal down, wishing to accelerate energetically, the speed pointer at first hardly moves along, but the consumption pointer hurries over clockwise, indicating a very high consumption, as indicated in broken lines in Figure 2. The large positive delta angle informs the driver instantly, at a glance, that his fuel consumption is very high. The driver's natural reaction is to bring his pedal back a little, to reduce the delta angle.

Figure 3 shows a possible construction for the instrument, as seen from the side. A positioning motor for actuating the speed pointer 2 is shown at 6. At 7 there is shown, for actuating the consumption pointer 3, a positioning transducer which converts a received signal which can, for example, be an electric signal or a hydraulic or pneumatic pressure signal, into an angular position for the consumption pointer 3. The spindle supporting the speed pointer is shown at 8 rotating inside a hollow shaft supporting the consumption pointer 3. The dial plate of the instrument is shown at 1. If desired the positioning transducer 7 can be located just behind the dial plate 1.In an alternative arrangement the speed pointer and the consumption pointer work on different centres, that is the circular speedometer scale is positioned next to the circular consumption scale on the dial As the two circular scales are nevertheless close together on the dial, the driver can read them both simultaneously and at a single glance. The relative positions of the two pointers can be displayed to the driver by special markings on the pointer tips, or by a window on one of the pointers.

Using the instrument as so far described the driver's criterion for normal fuel consumption at ordinary cruising speeds, and on a level road, is that the angle delta should have a small negative value. And this is appropriate for the average car.

But for a vehicle whose consumption curve differs considerably from the ordinary it is better to arrange that the criterion for normal fuel consumption is that the delta angle should be zero, that is that the two pointers should coincide.

This requires, if one considers Figure 2, a modification of the dial in that the consumption scale 5 is rotated in position, either clockwise or anti-clockwise, relative to the speed scale 4. A consequence is that the numerals of the consumption scale 5 are no longer radially in line with those on the speed scale in the sense mentioned above. And the positioning transducer 7 shown in Figure 3 must, of course, be adjusted in its angular position correspondingly.

In the version of the invention shown in Figure 4 the two pointers coincide whenever the vehicle is being driven economically. Extravagant driving produces a positive delta angle. A negative delta angle is obtained only during overrunning, that is when the car is driving the engine. It will be observed in Figure 4 that the consumption scale 5 is, in this case, graduated at non-linear intervals.

The response of the positioning transducer 7 must therefore also be non-linear. This can be obtained, for example, by interposing a non-linear drive between a pneumatic or electric transducer 7 and the hollow shaft 9 of the consumption pointer 3.

Furthermore, the display of consumption need not necessarily be by a pointer. For example a mechanically driven moving column can be used.

This is particularly convenient if vehicle speed is also displayed by a moving column.

In another version of the invention, shown in Figure 5, the rotary pointer for displaying speed is retained. Fuel consumption, on the other hand, is not directly displayed at all. What is displayed is a signal corresponding to the delta angle and, to simplfy the presentation, only positive delta angles are effective. In Figure 5 a rectangular panel 10 shows a parallel row of light-emitting electronic elements. With increasing delta angle the elements light up one after the other, starting at the left, so that a horizontal column of light is produced, the length of the column representing the delta angle. The light-emitting elements are controlled electronically by a power source situated behind the positioning motor 6 (Figure 3), the source responding to an input signal determined by the delta angle, only positive delta angles being effective.In further development of the invention the input signal is also used to trigger an audible warning which sounds on the occurrence of an excessive delta angle, somewhat after the manner of the audible warning with which certain vehicles are equipped to produce when driven at excessive speed. It is also advisable to arrange that the audible warning sounds only when the vehicle is travelling at above a certain speed, because an audible warning is undesirable at very low vehicle speeds, even though a high delta angle is produced under these circumstances during energetic acceleration. On the other hand, it is arranged that at abnormally high vehicle speeds the resulting very high fuel consumption causes the warning to sound continuously.

In a vehicle in which speed is displayed in the form of a lit-up numeral, rather than by a rotary pointer, an exessive delta angle can, for example, cause the lit-up numeral to change colour, or be otherwise optically emphasised.

As a further possibility the driver can be informed on whether he is driving economically or not by telling him how far he can travel with the consumption of a unit of fuel (litres/km, or miles/gallon). This can be obtained by displaying to him a signal derived from a mechanically or electrically inverted delta-angle input signal.

Claims

1. A process for indicating, at each instant, the rate of fuel consumption of an internal combustion engine in a motor vehicle, characterised in that the rate of fuel consumption at each instant is displayed simultaneously with the engine or the vehicle speed on a common dial.

2. A device for performing the process of claim 1, characterised in that a pointer (3) for indicating distance-based fuel consumption (KV) at each instant is displayed in front of the dial (1) of the speedometer.

3. A device as claimed in claim 2, characterised in that the dial (1) of the speedometer shows a graduated scale (5) for indicating fuel consumption.

4. A device as claimed in claim 3, characterised in that the fuel-consumption scale (5) is graduated in such a way that each fuel consumption reading (KV) correlates with a speed reading (vet) of n times its numerical value, where n is preferably 10.

5. A device as claimed in claim 2, characterised in that the fuel consumption pointer (3) is actuated by a positioning transducer (7) whose input signal is derived from a manometer or an electric measuring device.

6. A device as claimed in claim 5, characterised in that the speed pointer (2) is actuated by a positioning motor (6) on whose back face is mounted the positioning transducer (7).

7. A device as claimed in claims 5 and 6, characterised in that the positioning transducer (7) actuates the fuel-consumption pointer (3) through a hollow shaft (9) which surrounds the spindle (8) of the speed pointer (2).

8. A device as claimed in claim 5, characterised in that the centres of the two scales (4) and (5) are spaced apart on the dial, the positioning transducer (7) being located at any desired location behind the dial (1).

9. A device as claimed in claims 2 and 8, characterised in that the two pointers (2) and (3) are optically correlated by coloured marks on their tips, and/or by windows or the like.

10. A device as claimed in claims 2 and 5, characterised in that a non-linear positioning transducer (7) is used so that the two pointers (2) and (3) coincide in position as long as the vehicle is travelling at normal cruising speeds on a level road.

11. A device for performing the process of claim 1, characterised in that the dial (1) of the speedometer shows a column-type display for distance-based fuel consumption.

12. A device as claimed in claim 11, characterised in that the column-type display (10) is formed by electric light-emitting elements.

13. A device as claimed in claims 10, 1 1 and 12, characterised in that the positioning transducer (7) triggers an audible warning when distance-based fuel consumption (KV) exceeds a predetermined value.

14. An indicator device for performing the process defined in claim 1 and substantially as described with reference to any of the accompanying drawings.