Patent GB-539701-A (GB)
Title: Improvements in or relating to a power drive mechanism for a vehicle
IPC: B60K5/08
Filed: 1939-12-19
Abstract: 539,701. Motor vehicles with two engines. WILCOX, G. D. Dec. 19, 1939, No. 32536. Convention date, Dec. 19, 1938. [Classes 79 (iii) and 79 (v)] A vehicle is driven by a main engine 22 and an auxiliary engine 42 which is automatically started and brought into action when the load and speed conditions are such that the main engine cannot deal satisfactorily with them. In the arrangement described the auxiliary engine is brought into use when the main engine speed corresponds to a vehicle speed of between 20 and 35 miles per hour and the main engine throttle is wide open. The main engine drives the rear axle 14 through a change-speed gear-box 25, and the auxiliary engine can be connected to this gear-box through a clutch 92, Figs. 4 and 5, cardan shaft 34, gears 33, 29 and a countershaft 28 of the gear-box 25. Normally the clutch 92 is disengaged and the auxiliary engine is not running but the shaft 34 is always rotating when the vehicle is driven by the main engine so that if the clutch 92 is engaged and the auxiliary ignition system 79 energized the auxiliary engine is started up and assists the main engine. In the arrangement shown in Fig. 4 the clutch 92 is engaged by a solenoid 89 energized when three switches 76, 77, 78 are closed, these switches being respectively closed when (1) the vacuum in the main engine manifold 83 is that corresponding to full open throttle, (2) the main engine speed corresponds to above (say) 10 miles per hour, and (3) the main engine speed lies between the speeds corresponding to (say) 20 and 35 miles per hour. The auxiliary engine ignition 79 is energized simultaneously with the solenoid 89 and the throttle is opened by a connection (not shown) from the solenoid. As the auxiliary engine speeds up a connection 95 from its generator 93 de-energizes the solenoid and tends to disengage th clutch 92, but the latter is of the centrifugal ,type and re-engages as soon as the engine speed reaches a pre-determined value. The clutch may be constructed as shown in Fig. 5 in which the shaft 98 driven by the shaft 34 carries a sliding splined member 99 having a facing 100 adapted to engage a facing 108 on a member 107 mounted on a steep-pitched screw thread 113 on the engine shaft 96. When the solenoid 89 is energized a connection 106 on a lever 104 is pulled and the member 99 moves to the right to engage the member 107 and rotate the engine shaft 96. When the solenoid is de-energized a spring 102 disengages the clutch, but as the engine speed increases centrifugallyoperated levers 110 slide the member 107 to the left on its screw thread to engage the member 99 and transmit the drive from the auxiliary engine to the shaft 97 and the gear-box. In a modification the auxiliary engine clutch is an ordinary one and is operated by a vacuum cylinder connected to the main engine induction manifold and controlled by electric relays corresponding to the switches 76, 77, 78. The vacuum cyclinder also controls the throttle of the auxiliary engine. The auxiliary engine may be connected to the vehicle driving gear anywhere between the gear-box and the rear axle, and it may be situated in any suitable position such as that shown or at the rear of the rear of the rear axle. In the construction shown it is mounted on three rubber cushions 46, 47. The lay-out of the main and the auxiliary engines and the means connecting them forms the subject of Specification 539,736.