GB745378A - Improvements in or relating to the measurement of fuel consumption and efficiency - Google Patents

Abstract

745,378. Electric indicating systems. HUTCHINS, D. C., and BURTON, P. Jan. 20, 1954 [Jan. 29, 1953], No. 2523/53. Class 40(1) The fuel consumption of. an engine driven vehicle is measured by applying an e.m.f. proportional to engine speed and derived from a tachogenerator 9, Fig. III, to a resistance 6 the tapping 7 on which is varied manually or automatically in accordance with fuel consumption per unit time so that the current flow measured at 10 is a measure of displacement e.g. miles per gallon. Inverse reading in e.g. gallons/mile may be obtained by electrically dividing the fuel consumption by the speed. Preferably the current from the generator flows through a constant resistance network, Fig. IV, formed by the portion X of resistor 6 and a portion of a further resistor 11 tapped off at 7. For measuring efficiency, i.e. work/gallon, Fig. V a current proportional to speed is fed to a constant resistance primary network Y-12-14, at R and subdivided at moving contact 12, operated e.g. by a hydraulic dynamometer, in accordance with the torque transmitted, so that a current proportional to power passes through meter 15 and a secondary constant resistance network 6-7-10-11 similar to that of Fig. IV. The current through meter 10 is then proportional to the work done/ gallon and the meter may be calibrated as an efficiency meter. The current through meter 15 may be proportional to the nth power of the B.H.P. of the engine, according to the type of dynamometer used, in which case the resistance 6 must be varied according to the same power of the fuel consumption.