GB405184A - Improvements in or relating to the engine controlling means for motor vehicles - Google Patents

Abstract

405,184. Regulating. MAYBACHMOTORENBAU GES., Friedrichshafen-on- Bodensee, Germany. June 28, 1933, No. 18440. Convention date, July 1, 1932. [Class 7 (vi).] In order to obviate running of the engine of a motor-car continuously at a normal or low speed during free-run periods, and thereby permitting undue power for lighting &c. to be drawn from the storage batteries or other power reservoirs, auxiliary means adapted to function when the fuel control is released are provided for raising the idle or free-running speed of the engine from the normal to a higher value whenever the speed of the car itself exceeds a predetermined amount, the engine in such circumstances being employed for charging &c. purposes. In the arrangement shown, the normal free-running speed is determined by means comprising a liquid pump 3 driven from the crank shaft 1 and circulating liquid through an adjustable port 8 regulated by a set-screw 9. Should the engine speed exceed a selected minimum value, the pressure in front of the port 8 rises and a sliding piston valve 39 is actuated, thereby venting to atmosphere, through a port 12 and pipe 11, a chamber 13 in which a partial vacuum is normally maintained by connection to the induction pipe 24. A piston 14 and rod 16 are thereby moved downwardly and permit a spring 19 acting on the released accelerator pedal 20 to actuate the throttle 18 in a closing direction. The normal free-running speed of the engine can thus be set to any desired amount by adjustment of the set-screw 9. Coupled to the driven shaft 4 is a second pump 6 which circulates liquid through an orifice 31 regulated by set-screw 30 and arranged so that, when the car speed exceeds the pre-determined amount selected, the pressure behind the orifice 31 is diminished, and a piston 33 and rod 36 are moved downwardly to open a second valve 37. As this valve provides an additional passage from the space 7 associated with the part 8, the free-running speed of the engine is adjusted to a new and higher value, which can be determined by the provision of a third set-screw 38. The screws 9, 30, 38 thus fix the two free-running speeds of the engine, and the car speed at which the change from one speed to the other occurs. Means may be provided for automatically throwing the auxiliary control out of action when not required, e.g., to prevent over-charging of the batteries &c.