GB403598A - Improvements in or relating to injection pumps for internal combustion engines - Google Patents

Abstract

403,598. Fuel-injection pumps. BOSCH AKT.-GES., R., 4, Militõrstrasse, Stuttgart, Germany. Aug. 14, 1933, No. 22624. Convention date, Aug. 15, 1932. [Class 102 (i).] In a fuel-injection pump in which helical edges control both the suction port and a relief port, the timing of the commencement of injection is varied, without altering the amount of the charge, by rotation of the plunger, while the timing of the opening of the relief port, and hence the amount of the charge, is varied by rotation of a part of the cylinders. The helical edge 21 of the plunger co-operates with a suction port 12 and the timing of injection is varied by rotating, by means of a rack 32, a sleeve 28 which engages the plunger. An axial passage 23 in the plunger terminates in a relief port 24, which co-operates with a helical edge 22 on a sleeve 8, and the timing of relief is varied by rotating the sleeve 8. Alternatively a helical edge on the plunger may co-operate with a relief port in the sleeve 8. The sleeve 8 is formed with a shoulder which seats on a shoulder in a stepped guide bush 7, and both the sleeve 7 and bush 8 are positioned axially by the upper portion 11 of the cylinder, which is secured in position by the valve carriers 15 and the nipple 17. The sleeve 8 may be formed with teeth engaged by a rack projecting through an aperture in the bush 7, or, as shown, the sleeve 8 may be engaged by a sleeve 34, surrounding the bush 7, and rotatable by means of a rack 32. In the latter case the sleeve 28 surrounds the sleeve 34 and both are secured by a washer 29 engaged by the plunger return spring 6.