Patent GB-1429493-A (GB)
Title: Power unit comprising a supercharged internal combustion engine
IPC: F02B37/04
Filed: 1973-04-03
Abstract: 1429493 Supercharged IC engines FRANCE ARMED FORCES MINISTER OF 3 April 1973 [6 April 1972] 15992/73 Heading F1B A power unit comprises an I.C. engine supercharged by an exhaust gas driven turbo charger, the outlet of the compressor being connected to the turbine inlet by a by-pass conduit so that the engine is in parallel air-flow relation with the bypass conduit, which includes automatically controlled throttle means to develop a pressure drop in the air-flow passing through the by-pass conduit which is substantially independent of the rate of flow traversing the conduit and which is an increasing function of the pressure at the compressor outlet. A compression ignition engine 101 includes an exhaust gas driven turbo charger comprising a turbine 104 driving a compressor 103. A by-pass pipe 106 branches off the compressor delivery pipe and supplies air through a throttle valve 108 to a combustion chamber 107, which is also supplied with fuel. The valve head 108a is mounted on a spindle 108b which also carries a piston 110 which slides in a cylinder (not shown) or is mounted at the end of a bellows 108d. The pressure drop across the valve is #P, where the pressure upstream of the valve is P, and is adjustable by moving the piston along the rod, to vary the value #P which increases as a linear function of the pressure at the compressor outlet. Combustion chamber. Fig. 2 shows a combustion chamber in which a nozzle 10 is supplied with fuel from a tank 12 by pump 11. Air, from compressor 3 and line 7 enters the chamber housing and is divided into primary air which passes through ports 22 to a tube 13 and secondary air which flows through a throttle 21 into a tube 17 and hence to a zone 16 where it mixes with the combustion products. Valve member 25 is mounted on sleeve 24 which is slidable in the housing and is biased by a spring 33. The effective area of the ports 22 is varied by a slide valve 28b, having openings 28a and having a closed end which is subject on one face to the pressure in the pipe 13 and on the other face to the force of a compression spring 29 and to the pressure in a chamber 30 which is open to atmosphere through a restricted vent 31. This chamber may also be connected to the compressor delivery line through a pressure regulating valve 53. Slide valve 28b is also connected to a spindle 69 which carries a valve member 68 which moves to vary the effective crosssectional area of a port 39 through which fuel supplied to the nozzle 10 can return via pipes 36 and 43 to the tank 12. Operation. When the pressure on the inside of the slide valve increases, the valve moves to the left, reducing the rate of flow of primary air and opening the port 39 so that a reduced quantity of fuel is discharged from the nozzle 10, thus maintaining a stoichiometric air/fuel ratio. In a modification. Fig. 3 (not shown) the port 39 is closed as the slide valve moves to the left, the port in this case being situated in the flow line to the nozzle 10. The spring 33 may be replaced by a piston and cylinder type viscuous fluid damping device.