Measuring and testing – Liquid level or depth gauge – Float
Patent
1985-09-04
1987-10-13
Yasich, Daniel M.
Measuring and testing
Liquid level or depth gauge
Float
73317, 338 33, 361 91, G01F 2330, G01F 2336
Patent
active
046990038
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a fuel float type meter for vehicles.
Fuel meters of this general type are commonly used, and in normal cases the resistor is of the rheostat type, i.e. it has the function of an adjustable resistor, and is connected in series with an indicator instrument of bimetallic type, the battery voltage lying across this series connection. When the tank is full, the resistance is low and the indicator instrument registers high current. When the tank is emptied, the resistance increases and the current drops.
As is known to all car owners today, a fuel meter of this type can only give a rather inaccurate information on the quantity of fuel remaining in the tank, even if the condition of the metering equipment is as good as new. This can be explained in many ways. The indicator instrument used is not particularly accurate but its primary advantage is the rugged design and the reasonably low price. The sensor itself, including resistor and float, is furthermore difficult to design as a linear instrument in that the configuration of the tank usually prevents the fuel level from varying linearly with the volume of residual fuel. Although this can be counteracted by making the resistance non-linear, the problem still remains that different car models have different tank shapes, and that in the implemented coupling system having varying resistance in series with a current meter, it will hardly help to make the resistance itself linear in response to the quantity of fuel, and therefore fuel meters giving quite approximate values have had to suffice for this purpose.
A specific problem associated with the previous design is the requirement of vigorously changing the resistance when the fuel level is low for the scale deflection to be appreciable, and it is difficult to obtain a reasonable degree of certainty of the zero point. The instrument often indicates zero although 10 liters or more may still remain in the tank. To overcome this problem, specific solutions have been found necessary such as a separate, connectible reserve tank. The car owner generally finds himself compelled to have a small reserve tank lying loose in the luggage compartment in order to avoid fuel stoppage.
Another example of a frequently practiced method is to connect in series an electric lamp and an NTC resistor to the battery, the NTC resistor being mounted close to the bottom of the tank. When the resistor is exposed as the fuel level lowers, the cooling effect is deteriorated, the resistor becomes warmer and the resistance decreases, the current thereby being sufficiently strong for the lamp to be lit as a warning to the driver. In this way however, only a purely qualitative indication is given, informing that some not too well-defined minimum level has been underpassed.
Also designs with automatic scale shifting have been suggested, which start to function when the fuel level drops below a predetermined value. Examples thereof can be found in U.S. Pat. Nos. 2,533,091 and 4,157,138. The former specification discloses two different rheostatic resistors each having its own movable contact coupled to a single float, one resistor covering only part of the range of movement of the float but having there the same interval of resistance as the other resistor will change for the entire range of the float, there being provided a third movable contact for a changeover of the rheostats' connection to the measuring instrument. At the lower level, the deflection of the instrument therefore shifts from operation on a scale range of 0-100 liters to 0-10 liters, for example. The latter specification shows resistance means connected to the float in the form of two resistors disposed in the respective extension of one another and having equally large resistance, and the slidable contact which is grounded can slide over the upper resistor for e.g. the 10-50 liter range, the upper connection of this resistor producing a resistance to ground varying from the entire resistance value and down to zero, and for the 0-10 liter range across the sec
REFERENCES:
patent: 2079485 (1937-05-01), Bousman
patent: 2282496 (1959-04-01), Greibach
patent: 2516452 (1950-07-01), De Giers et al.
patent: 2526006 (1950-10-01), Cress
patent: 2533091 (1950-12-01), Campani
patent: 2536465 (1951-01-01), Reeves
patent: 2560257 (1951-07-01), Sias
patent: 2844030 (1958-07-01), Svannel
patent: 2903646 (1959-09-01), Loos
patent: 3464012 (1969-08-01), Webb
patent: 4157038 (1979-06-01), Yamamoto
"Electronic Measurements", F. E. Terman et al., p. 1, McGraw Hill, 1952, 2nd Edition.
"Diode Protect Meter from Overloads", P. Blais, Electronics, pp. 85-86, Sep. 6, 1965.
AB Volvo
Yasich Daniel M.
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