GB1344841A - Injection devices for compression-ignited internal combustion engines - Google Patents

Abstract

1344841 Fuel injection pump AUTOMOBILES PEUGEOT 11 May 1971 [8 June 1970] 14308/71 Heading F1A In a "distributor" or "in-line" fuel injection pump wherein the quantity delivered to an injector outlet 6 is modified by allowing part of the fuel delivered from the pumping chamber 9 to enter a fixed or variable volume deduction chamber 43, a piston member 35 prevents deduction occurring above a predetermined speed. Fuel deducted enters the chamber 43 via passages 7, 24, a non-return valve 30 and a throttle 40 in the piston member 35. Because of the pressure drop across the throttle 40, the piston member 35 is displaced to the right against the action of a spring 37. This closes a return passage 38 for the deducted fuel until the spring 37 returns the piston member 35 to the position shown, this being arranged to occur after the deduction chamber 43 is disconnected from the pumping chamber 9. When the chambers 9, 43 are again connected, the deducted fuel can flow through the return passage 38 into the pumping chamber 9. As the speed increases the piston member 35 has a shorter time in which to complete its return stroke and thus the amount of fuel returned progressively decreases and thus also the amount deducted during the next stroke. Eventually the piston 35 has insufficient time to return before the next injection stroke. Below a certain speed the deduction chamber may be disconnected from the pumping chamber by a valve, Figs. 10 and 11 (not shown) responsive to accelerator lever position or feed pump pressure.