GB666065A - Automatic regulating device for internal-combustion engines, in particular of motor vehicles - Google Patents

Abstract

666,065. Change-speed control. HEFEL, K. May 13, 1948, No. 13189/48. Class 80 (ii). [Also in Groups XXVII and XXXI] In a motor vehicle in which power outputs selected by an operator-controlled pedal or other member are achieved and maintained by changes in transmission ratio, the necessary changes are indicated or effected by means acted upon differentially by two elements, the first of which is moved in correspondence with an actual engine operative factor such as the speed of the transmission input or output shaft and the second of which is actuated, so as to correspond to a required engine speed for the output selected, by the operator-controlled member which acts thereon and on the fuel supply control through guides shaped to follow suitable characteristic curves such as those corresponding to the most economical operation of the engine. As shown, a single pedal 1, Fig. 2, slides in unison a cam plate 3 forming one shaped guide and operating the throttle valve 7 through a link 6, and a plate 4 carrying an insulating strip 8 forming the other shaped guide and separating two contact zones 11, 12 in series respectively with earthed solenoids 15, 21. A battery-fed contact 9 is adjusted across the plate 4 by a centrifugal governor 10 by the gear box input shaft. According to the contact zone on which the. contact 9 rests, one or other solenoid 15, 21 is energized to draw a servomotor control valve 18 one way or the other to adjust the transmission ratio through the servomotor 19. The pedal 1 has a range of action at each end of its travel during which the valve 7 remains fully opened or closed, the guide 8 being shaped so as to follow the desired characteristic curve over these ranges the closed throttle one of which gives varying engine braking output. In a modified form, Fig. 6 (not shown), using engine induction manifold suction instead of engine speed to control the ratio changes a single plate slidden from a control pedal carries cam slots controlling respectively the throttle valve and one end of a differential lever the other end of which is linked to a servomotor control valve as before and which is acted on intermediately by engine-suction responsive bellows. In Fig. 8 a pedal 51 rotates, through a rack and pinion, a shaft 47 carrying cams controlling a number of engine working factors and having shapes derived from corresponding engine operating diagrams so as to achieve maximum engine efficiency. Cams 48, 49 actuate the carburetter throttle and auxiliary air valves and a cam 50 alters the ignition timing. A cam 52 and a centrifugal governor 52<SP>1</SP> responsive to vehicle speed operate logarithmically racks 27', 28<SP>1</SP> so that a pinion 29<SP>1</SP> is moved differentially to select the correct transmission ratio as through a mechanically, electrically, hydraulically or pneumatically operating servo-control. The necessary ratio change may be actually effected, or the necessity therefor merely indicated as by signal lamps. A further cam 53 is provided which is cylindrical over the whole power range of the engine but has a raised part for actuating expanding shoe vehicle brakes 54 when the highest permissible engine speed is attained during engine braking. The cam 53 may be replaced by a stop on one of the other cams. In Fig. 7 (not shown), three carburetter controls, a fuel regulating member, a throttle valve and an additional air valve, are jointly operated from a mutual cam through individual cam linkages. Manual overriding means for varying the transmission ratio may be provided, such as a dashboard handle which additionally adjusts the cam of the appropriate transmission-regulating rack, or pulls the rack against spring action clear of the cam. The handle may be additionally operable by the vehicle clutch pedal. Similar manual overriding means may be provided for the other cam means. A servo-motor may be used between the operator-controlled member and the fuel supply control, in parallel with a lost-motion mechanical connection which acts on sudden complete throttle closing or opening, to override the servo-motor if the latter lags appreciably, an elastic coupling in the servomotor connection allowing such override. Specification 506,739 is referred to.