US2207880A

US2207880A - Fuel consumption indicator

Info

Publication number: US2207880A
Application number: US237323A
Authority: US
Inventors: Skoldberg Per Olof
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-11-09
Filing date: 1938-10-27
Publication date: 1940-07-16
Anticipated expiration: 1957-07-16

Description

July 16,1940.

P. Of SKLDBERG FUEL CONSUMPTION INDICATOR Filed Oct. 27, 1958 2 SheelLs-SheeI l fw @fof seaczmfg- MMM wvl alu-"urn up! f Patented July 16, 1940 uNlTEo sTATEs PATENT OFFICE Per Oloi.' Sl'xldberg, Stockholm, Sweden.

Application October 27, 1938, Serial No. 237,323 v In Sweden November 9, 1937 1 Claim.-

engine is in operation. A further object of the invention is to provide an apparatus for the pur.- pose indicated, which is of simple construction and readily applicable to existing engines and which .directly indicates the fuel consumption in, for instance, gallons per mile or miles per gallon.

attain these objects by mechanism illustrated in the accompanying drawings, in which: Fig. 1 is a vertical section of4 the apparatus; Fig. 2 shows, to a larger scale, a detail of the novel apparatus;

Fig. 3 is a section taken on the line 3-3 of Fig. 2; y

Fig. 4 is a diagram illustrating certain pressures in relation to the position of the throttle valve of the carburetor; and

Fig. 5 is another embodiment of the invention. Referring rs't to Fig. 1, I have illustrated a carburetor of a well-known type, generally denoted by C and including gasoline inlet Ill, iioat chamber II, iioat I2, float valve I3, compound 35.1noz`zle I4, idling nozzle I5, air intake I6, choke tube I1, and throttle I8. The carburetor itself forms no part of the invention and may be of any desired type. I9 indicates the inlet pipe for the mixture of gasoline vapor and air, said pipe 40 being connected to the intake manifold (not' illustrated) of the engine.

A pipe is connected to the choke tube Il by means of a nipple 2| screwed through the wall of the pipe 22 and secured in proper posi- 45 tion by a nut 23. A pipe 24 is connected to the inlet pipe I9 at-a place behind the throttle I8,

'umn of mercury indicatedin millimetres.

the drawing, the nipple 425 can easily beadjusted so that the axis of the aperture 29 will form any desired angle a with the direction of flow of the combustion gases through the inlet pipe I9,

said direction being substantially parallel to the longitudinal axis 3I. Nipple 25 is provided with a hexagonal portion 34 by which the nipple may be turned to vary the direction of axis 30..

The' pipes M'and 2t are connected to a diierential gauge 32 including a scale 33 and a pointer 3d 'and adapted to indicate the diiierence between the pressure prevailing before the throttle i8 and the pressure behind the throttle. The gauge 32" is conveniently placed on' the instrument panel. As will be seen from the following consideration in connection with the diagram shown in Fig. 4, any pressure difference indicated by the gauge t2 corresponds approximately to a certain fuel consumption per revolution of the engine. n

In Fig. 4, the abscissae of the coordinate system represent the position oi the throttle I8 and the ordinates thereof represent pressure in coll-/I indicates the position in which the throttle is full open, whereas' at O. the throttle entirely closes the intake to the engine.

The curves 'p1 and p1 indicate the static pressure prevailing before the throttle i8, and the curves p2 and p2' indicate the static pressure behind the throttle, both at two diierent b'ut constant speedsv of the engine, n and n', respectively, the speed n' being higher than n. lf the engine speed is assumed to be constant, the position of the throttle is a measure of the load on v the engine.

the throttle position B where b=p1-pz'=a. If

Q and Q', respectively, denote the corresponding quantities of fuel iiowing to the engine per unit of time, the fuel consumption per revolution Vwill counted in the direction of flow of the combusbe tion gases. A nipple or joint 25, which is secured in its positionby the nut 26 and connected to the pipe 24 by the nut 21, has a central passage Q QQ It follows therefrom that the pressure dierence pi-pz indicated by the differential gauge 32 is l a measure of the fuelcons'umption per revolution and consequently also per unit of -length of the road on which a motor car or the like runs, proactly to the real fuel consumption. In the embodiment shown, such compensation is obtained.

by varying the angle a between the direction of ow of the combustion gases and the longitudinal axis of the aperture 2Q. The less thelangle a, the greater will be the pressure acting on the gauge due to the kinetic energy of the mixture. In this way, the aperture 29 can be adjusted, and the gauge calibrated, such as exactly to indicate the consumption oi fuel, for instance in gallons per mile or miles per gallon, which consumption canA be directly ascertained on the gauge.

In case of motor cars, the pipe 24 can be connected to the intake tube I9 at the place where the pipe, through which the vacuum windshield wiper is actuated, is connected to the tube i9, whereby the provision of a special aperture in the wall of the tube i 9 is avoided.

While the embodiment ci the invention described above is constructed in accordance with theoretical considerations, I have found that the same results can be obtained by means of a same type as that illustrated in Fig. 1. Il is a vacuum gauge which by means of a pipevu'` is connected to the inlet pipe Il' at a' place behindthe throttle i8. The connectbn between the pipes 24' and I l' is eiiected by a nipple 2B' provided with an aperture 29' the position of whichI canbe varied in the-same mann'er and for the same purpose as described in conjunction with the aperture 29 of the embodiment shown in Figs. 1 vto 3. In a certain position of the aperture 29', which position must be ascertained experimentally, the gauge can be calibrated so that it directly indicates the fuel consumption. What I claim is: g Y An instrument for indicating the fuel consumption .of an internal combustion engine having a carburetor and a throttle valve between the carburetor and the inlet pipe of the engine, said instrument including a pressure gauge, atubular member for connecting said gauge with the inlet pipe, said tubular member having a rotatable adjustable portion extending into the inlet pipe and provided with an aperture adapted to be PER omr' sKLpBEaG.