Patent GB-1472991-A (GB)
Title: Metering fuel consumption of engines
IPC: F02M55/00
Filed: 1974-04-23
Abstract: 1472991 Liquid meters; IC engine fuel supply systems C L ERWIN Jnr 23 April 1974 17779/74 Headings F1A and F1B [Also in  Divisions F2 and G1] A system (Fig. 1) for supplying fuel to an engine 10 such as a diesel engine from which unburned fuel is returned via a treatment tank 146 to a fuel supply line 14 downstream of a meter 16, includes remote indicating means 132 for indicating the rate of fuel consumption or the total amount of fuel consumed. The tank 146 may remove air bubbles from the returned fuel and may cool the fuel. The system may also include means (155) for controlling the temperature of fuel fed to the engine Fig. 10 (not shown). The meter  As shown the meter 16 comprises a cylinder defined by sleeve 22 and a piston 100 to reciprocate in the cylinder under the pressure of fuel admitted alternately to regions on opposite sides of the piston. Guide posts 46, 48 in the cylinder slidably support a plate 56 and a slide 60 so that they can reciprocate transversely in the cylinder. The slide 60 has projecting arms 68 which guide a shaft 72 passing through a hole in a trip element 70 attached to the plate 56, compression springs 76, 78 being mounted between the element 70 and the arms 68. The plate 56 also has a tab 80 supporting a spring-loaded cup valve 82 which serves to communicate either passageways 36 and 40 or passageways 38 and 40. The passageway 36 communicates with inlet 32 and the passageway 38 with outlet 34, the passageway 40 being connected via a passageway 42 outside the sleeve 22 with the region under the piston 100. A piston rod 88 to which piston 100 is attached is slidable mounted on a port 44 and has a pin 90 and a cutout portion 94. As the piston 100, and rod 88, driven by fuel flow, move in a direction determined by the portion of valve 82, the slide 60 is pushed by the camming action of pin 90 to one side or the other so compressing one or other of the springs 76, 78. When the piston 100 rises, the element 70 is able to pass through the cut-out portion 94 to allow the compressed spring to change the position of the valve 82 reversing fuel flow through the cylinder and thus the direction of the piston 100. The pin 90 engages a sinuous slot 102 in the periphery of a rotatable cam 104 such that reciprocation of piston 100 rotates the cam and causes rotation of a gear 118, drive shaft 119 and flexible output cable 122 extending to an indicator (132), Fig. 8 (not shown), reading volume flow/unit time and total volume flow. The indicator (132) can be adjusted for the density of the fuel to read mass flow rate. Alternatively the output of the meter 16 can, as in Fig. 12 (not shown) be combined with the output of a speedometer (174) to give a direct reading of fuel consumption/unit distance travelled.  In a modified embodiment Fig. 14 (not shown), the piston (100) comprises two plates (238) of a metal of high expansion coefficient. Temperature changes are thus automatically compensated since expansion of the plates (238) changes the working volume of the cylinder. The plates (238) can also be compressed or relaxed by a manually-operable knob (250) according to the density of the fuel. In this embodiment the output shaft 119 drives a counter mechanism (256) directly and a flexible shaft (270) as in Fig. 16 (not shown).