Patent GB-1262138-A (GB)
Title: Compression-ignition engines supercharged with compensation for different engine speed and load conditions
IPC: F02N19/00
Filed: 1969-01-27
Abstract: 1,262,138. Variable-speed gear. SOC. ANON. DE VEHICULES INDUSTRIELS ET D'- EQUIPEMENTS MECANIQUES. 27 Jan., 1969 [7 Feb., 1968 (2); 7 Aug., 1968; 8 Aug., 1968; 5 Dec., 1968], No. 4490/69. Heading F2D. [Also in Division F1] A compression-ignition engine 1 is supercharged by a turbo-supercharger 3, 5 in series with a positive displacement pump 10, and a heat exchanger 7 through which engine cooling liquid flows at a regulated temperature is arranged therebetween. The pump 10 is driven from the engine crank-shaft 14 through a variable ratio transmission and the transmission ratio may be varied continuously between two limits in accordance with a reference pressure comprising at least the pressure upstream of the pump. At one of the ratio limits the pump 10 increases the supercharging pressure as compared with the supercharger outlet pressure, whereas at the other limit it decreases the pressure. The pump 10 may be a Roots blower, Fig. 3 (not shown), or a vane or piston pump. The transmission may comprise a V-belt 15 and pulleys with flanges 18 and 19 movable relative to flanges 16 and 17. The flanges 18 and 19 are mounted at the ends of a rocker 20 pivotable about its mid-point by a diaphragm assembly 25, 26. The pressure acting on the diaphragm is composed of the pressures upstream and downstream of the pump 10 and atmospheric pressure acting through respective calibrated orifices 29, 31 and 32. The transmission may be hydrostatic, Fig. 4 (not shown), and comprise an axial piston motor (44) and an axial piston pump (42), the motor swash-plate (45) being adjustable by a diaphragm assembly 46. At engine starting the pump 10 may be driven from the starter motor pinion 39 by a gear 37. In the illustrated embodiment the belt transmission is disengaged by moving the rocker pivot 23 with a linkage 40, 41 connected to the pinion 39 or an electromagnet energized with the starter motor at engine starting. The hydrostatic transmission, Fig. 4, has the pump (42) short-circuited by a valve (49). In a further embodiment of the transmission, Figs. 5 to 8 (not shown), an adjustable pulley (56, 64) driven by a V-belt from a constant diameter crank-shaft pulley (69) is coupled to the air pump shaft (13) by a universal joint (53) and a shaft (54). The adjustable pulley is mounted for movement relative to the constant diameter one by a casing (59) at the free end of a leaf spring (60) supported on the engine. The adjustable flange (64) of the pulley is movable by the reference pressure within a bellows (66) and the change in effective pulley diameter is accompanied by movement relative to the crank-shaft pulley (69). In another embodiment, Figs. 9 and 10 (not shown), the adjustable pulley flange (64) is biased towards the other flange (56) by a compression spring (67) and the pulley is movable relative to the crank-shaft pulley by a rolling diaphragm actuator. The cylinder (88, 91, 94) of the actuator is mounted for pivoting movement on the engine casing (87) and the rolling diaphragms (77, 93), between a pair of pistons (78, 92), define a space in which the reference pressure acts.