GB1156327A - Liquid Fuel Injection Pumping Apparatus - Google Patents

Abstract

1,156,327. Fuel injection pumps. C. A. V. Ltd. Oct.31, 1966 [Nov.15, 1965], No.48372/65. Heading F1A. [Also in Division G3] In a fuel injection pump having a throttle member 20 controlling the fuel output and a fuel pressure operable piston 24 controlling the timing, the throttle member controls a port 27 in the fuel flow path to the timing piston cylinder including a restriction 30 downstream of the throttle member, such that variations in the setting of the throttle member will produce variations in the timing. The pressure upstream of the restriction 30 and the bias of spring 26 are applied to the piston 24 in opposition to the outlet pressure of the feed pump 17 which varies in accordance with driving speed. The feed pump pressure acts on the piston 24 via passage 18 and check valve 25. The restriction 30 communicates with a drain and fuel is supplied upstream thereof from the feed pump via passage 18, restriction 28, port 27 and passage 42. The pressure upstream of the throttle 20 is maintained substantially constant by a valve 29. The throttle 20 is moved against the bias of an adjustable governor spring 23 by the outlet pressure of the feed pump acting on its inner end. In a further embodiment, Fig. 3 (not shown), the pressure downstream of the throttle controlled port (27) acts on the timingpiston in opposition to the spring-bias and the passage connecting the port to the timing piston cylinder is connected to a drain through a restriction (30). The feed pump outlet pressure does not act on the timing piston and the pressure upstream of the throttle controlled port (27) is maintained substantially constant by a valve (29). In a modification of the embodiment of Fig. 3, Fig. 4 (not shown), the port (31) to the timing cylinder is controlled by the inner end of the throttle member (20) and the constant pressure valve is omitted. In another embodiment, Fig. 5 (not shown), the fuel from the feed pump acts on the inner end of the throttle member (20) via a constant pressure drop valve (32) and a centrifugal regulator (33) which spills fuel to provide a pressure which varies in accordance with the square of the speed. The pressure acting on the timing piston is controlled by the throttle controlled port (34) and a by-pass downstream of the throttle member (20) and upstream of the timing cylinder which is connected to the passage between the constant pressure drop valve (32) and the throttle member. In a modification of this embodiment, Fig. 6 (not shown), fuel is supplied to the engine via the constant pressure drop valve (32) and a passage in the throttle member (20).