Patent GB-1424127-A (GB)
Title: Internal combustion engine electrically controlled fuel injection  systems
IPC: G01F1/28
Filed: 1973-01-19
Abstract: 1424127 Regulating IC engine fuel injection ROBERT BOSCH GmbH 19 Jan 1973 [21 Jan 1972 5 Feb 1972 21 Sept 1972] 2813/73 Heading F1B [Also in Divisions G1 G3 and H1] In an I.C. engine, electrically controlled fuel injection system of the type providing engine synchronized injection valve energizing pulses having a duration determined by the discharge time of an electrical energy storage device (capacitor or conductor), which is charged in a defined manner prior to each discharging operation, an  air intake meter LM is provided and includes a baffle flap 30 arranged in a housing 41 adapted to form part of the intake manifold 25 for pivotal movement against a restoring force and coupled to a device R for influencing the charging and/or discharging of the storage device, the flap 30 being connected to a damping vane 47 and to a hub 48 one end of which is journalled in the housing 41. As shown, the hub is pivotally mounted on a shaft 51 which has an extension 71. The restoring force is provided by a spiral spring 65, Figs. 6 or 14 (not shown), attached at its inner end to a cam 70  fixed on the extension 71, and at its outer end to an annular disc provided with teeth engaged by a pinion to enable the spring force to be adjusted. The material of the spring may a nickel-beryllium alloy. For temperature compensation the end of the spring which engages the extension is made of a temperature-compensated resilient material, e.g. having a negative temperature coefficient, having a constant, temperature dependent E-modulus. The temperature of the spring may be maintained the same as that of the intake air by using a by-  pass of the plate (30), Fig. 14 (not shown). A body 78, provided with a balancing weight 79, 80, supports the wiper 81 of a potentiometer forming the device R. The wiper has a pair of contacts 82, 83 which engage a resistive strip 84 formed on a plate 85. Details of the plate 85 and its resistive mountings are described with reference to Fig. 9 (not shown), the resistive mountings being inter-connected and connected to contacts 90, 91, 92 in a plug socket 95. A tongue 86 attached to wiper 81 engages a spring contact 88 leading to a contact 89 in socket 95. A pair of spring contacts 96, 97 are also provided, contact 96 being disengaged from contact 97 by an arm 99 when the engine is turned off. The damping vane 47 is formed integrally with the hub 48 and is arranged in a pneumatic damping chamber 62 forming part of the housing 41. The baffle flap 30, also formed integrally with hub 48, is provided with a relief valve 110, 111, 112 which opens when backfiring occurs. A by-pass 105, provided with an adjustable restrictor 107, 108, Figs. 7 and 8 (not shown), is also provided to enable the air/fuel ratio to be adjusted. In a modification, Fig. 10 (not shown), an altitude correction is provided by a valve 141 arranged in a wall of the damping chamber 62, the valve being opened to a varying degree, depending upon the ambient pressure upstream of the plate 30, by a bellows 140. The pressure in the damping chamber is then varied thereby varying the dependence of the position of the plate 30'upon the quantity of intake air.  In a further modification, Figs. 11-13 (not shown), altitude correction is provided by an air valve, in the form of a piston and diaphragm  arrangement, which controls the pressure in the  damping chamber via a plurality of apertures which are progressively covered by the damping vane as it rotates.