Zexel Gmbh

Tohru Yokota

Hiroshi Ishiwata

Mitsuaki Kobayashi

Takashi Ohishi

Nobuhiro Kitahara

Teruo Ohsawa

Tsutomu Katori

Toshihumi Noda

An objective of the present invention is to provide a fuel injection pump wherewith, in addition to main injection, pre-injection is made possible in the vicinity of top dead center in the exhaust stroke, and wherewith, by regulating the pre-stroke, defined as the stroke from bottom dead center of a plunger 2 to the commencement of fuel line pressurization, it is possible to freely control both the pre-injection volume and the pre-injection timing relative to the main injection. Attention having been given to the combining of a pre-stroke varying mechanism together with a two-stage injection mechanism, the present invention is a fuel injection pump that is made so that a pre-stroke is regulated by changing the relative positions, in the axial direction, of a plunger 2 that sends fuel under pressure and a control sleeve 3 that fits around the outside of the plunger 2 so as to slide freely thereon. The cam 4 that drives the plunger 2 comprises a main cam nose 20 for main injection use and a pre cam nose 21 for pre-injection use.

Fuel injection pump

The present invention provides a fuel injection pump plunger whereby it is possible to avoid deformation of the timing sleeve 11 in the fact of increased fuel pressure, to ensure no-injection state even with elimination of the furrow, and to prevent secondary injection. It results from the realization that it is possible to replace the furrow with an aperture with which the spill port can connect in line with the movement of the plunger 20, and is wherein an aperture (horizontal aperture 21) is provided below and separate from said inclined lead 10, this aperture 21 being such that it is not only connected with said central fuel passage 8, but in the no-injection position of said control rack 13 allows said spill port 12 to engage either with this aperture 21, with said inclined lead 10, or with both of them, the area of the aperture when they engage being the same as the area of said central fuel passage 8.

Fuel injection pump plunger

A prestroke controller 31 for an engine fuel injection pump 30 utilizes a magnetic coupling 26 and, by taking advantage of the fact that the secondary side (driven side internal magnet) of the magnetic coupling can be controlled to a desired position without being driven by force from a flyweight 11 on the primary side (driving side external magnet), not only secures speed timer characteristics but also provides a greater degree of freedom in determining the injection timing advance characteristic. The prestroke controller 31 includes the magnetic coupling 26 as a member of a displacement transfer section provided between the flyweight 11 and the timing control rod 6 and also includes an add-on device 36 for injection timing advance adjustment which can be engaged with or disengaged from the timing control rod 6 and is capable of controlling the prestroke independently of the magnetic coupling 26.

Prestroke controller for engine fuel injection pump

A fuel injection pump for an engine comprises a magnetic coupling 37 straddling a partition 36 for connecting a timing control rod 6 and a displacement transfer section 34 of a governor so as to enable efficient transfer of rotational force from the displacement transfer section to the timing control rod without need for an oil seal therebetween, and a prestroke controller for the fuel injection pump 131 includes an injection advance adjustment add-on device 136 for conducting prestroke control independently of the magnetic coupling and thereby provide greater freedom in establishing injection timing advance characteristics by enabling injection timing control in response to temperature or load and/or a safety mechanism 237 for ensuring operation of a governor mechanism 20 based on movement of a flyweight 11 even if the magnetic coupling should stick.

Fuel injection pump and prestroke controller therefor

A prestroke adjustment mechanism for a fuel injection pump comprises a U-shaped lever provided on the outer surface of the pump housing for rotating a timing control rod of the injection pump and a rotation limit pin provided on the same outer surface for limiting the rotation of the U-shaped lever. The timing control rod is linked with a control sleeve on the pump plunger for adjusting the prestroke. By limiting the rotation of the U-shaped lever, the rotation limiting pin limits the height of the control sleeve for ensuring establishment between the top of the control sleeve and the bottom of the upper section of the plunger barrel of a gap for dissipating the force of the spill jet during fuel spill. As a result, the downward force of internal turbulence produced by the spill jet is dissipated, thereby preventing the control sleeve from slipping downward and ensuring stable and reliable prestroke adjustment.

Growing community of inventors

Higashimatsuyama, Japan

Tohru Yokota