Fuel consumption meter

Claim 1

A fuel meter for accurately measuring the quantity of fuel consumed by a vehicle with the accuracy of said measurement being completely independent of the rate of fuel demand by the vehicle engine, comprising a unitary housing adapted to be mounted on said vehicle at a position remote from the fuel tank of said vehicle, a normally inoperative fuel pump mounted on said housing, said housing including a single normally empty, accurately calibrated, volumetric measuring chamber having an inlet and an outlet, said housing further including a fuel reservoir chamber having a volumetric capacity significantly greater than that of said measuring chamber, said reservoir having an inlet and an outlet, an inlet conduit in said housing for supplying fuel from said vehicle fuel tank to the inlet side of said fuel pump, a first conduit in said housing connecting the outlet side of said fuel pump to the inlet of said measuring chamber for supplying fuel only to said measuring chamber when said pump is activated, a normally closed valved conduit between the outlet of said measuring chamber and the inlet of said reservoir chamber for supplying fuel, in an exactly measured increment, from said measuring chamber to said reservoir chamber when said valved conduit is opened, and an outlet conduit for connecting the outlet of said reservoir chamber to the engine of said vehicle to permit said vehicle engine to draw its fuel requirements only from said reservoir chamber, said valved conduit being so positioned that any fuel in said measuring chamber is completely isolated from fuel in said reservoir chamber by an intervening fuel-free space whereby the fuel increment measuring operation of said measuring chamber is independent of the withdrawing of fuel from said reservoir chamber by the vehicle engine, first sensor means for monitoring changes in the level of fuel in said reservoir chamber as said vehicle engine draws its fuel requirements therefrom, control means responsive to said first sensor means for selectively activating said normally inoperative fuel pump when the fuel level in said reservoir chamber falls to a predetermined level to cause said pump to supply fuel from said inlet conduit to said normally empty measuring chamber, second sensor means for monitoring the quantity of fuel delivered by said pump to said measuring chamber, said control means also being responsive to said second sensor means and being operative to deactivate said pump when a predetermined, precisely measured increment of fuel has been delivered to said measuring chamber and being operative substantially simultaneously to open said normally closed valved conduit thereby to completely empty said precisely measured fuel increment from said measuring chamber into said reservoir chamber, and counter means responsive to operation of said control means for registering the number of times that such precisely measured increments of fuel are emptied from said measuring chamber into said reservoir chamber.