A method of controlling a fuel injection device that can control a small amount of injection is provided. A fuel injection device for use in an internal combustion engine, includes: a valve body that can open and close a fuel passage, a needle that transfers a force with the valve body, and executes valve opening/closing operation, and an electromagnet that includes a coil and a magnetic core provided as a driver for driving the needle, and a cylindrical nozzle holder disposed on an outer periphery of the magnetic core and the needle, in which a current is supplied to the coil to exert a magnetic attractive force between the magnetic core and the needle to open the valve body.

Fuel injection device

In a magnetic valve controlled fuel injector for a storage fuel injection system of a multi-cylinder internal combustion engine wherein the injector includes an upper housing part with a control piston, a lower housing part with a valve piston, a nozzle body with a spring loaded needle valve, and a fuel supply passage extending through the lower housing part to the valve piston and through the valve and control pistons to a control chamber from which fuel can be released under the control of a magnetic valve disposed on top of the upper housing part. The fuel supply passage further extends from the valve piston to a pressure chamber around the nozzle needle which when unseated by opening the magnetic control valve permits ejection of fuel from the pressure chamber. The valve and control piston which are disposed in the lower and respectively, upper housing parts are disposed in engagement with each other in the area of the jointure of the upper and the lower housing parts.

Magnetic valve-controlled injector for a storage fuel injection system of a multi-cylinder internal combustion engine

The hydraulic control device (20) of the fuel injection valve (10) comprises a pilot valve (70). The pilot valve rod (66) co-operates with both the actuator (18) and the pilot valve seat (68). A discharge chamber (72) is located adjacent to the pilot valve seat (68) and is connected to the low-pressure outlet (76) by means of a throttle passage (74). In order to complete the injection process, the pilot valve rod (66) is inserted into the discharge chamber (72) until it hits the pilot valve seat (68). This leads to an increase in pressure which, in turn, leads to the control body (38) being rapidly lifted from its position on the discharge chamber body (46). The injection valve member (22) is thereby displaced very rapidly into the closing position thereof in order to complete the injection process. The movement of the pilot valve rod (66) can also be mechanically used to support the rapid closing movement of the injection valve member (22).

Fuel injection valve controlled by a pilot valve

The actuator piston (26), which is moved back and forth by the actuator (18), has a piston surface (86), which delimits the control space (36), and has, on the opposite side, a compensation surface (88) that delimits the compensation space (24). The compensation space (24) is connected to the high-pressure space (34) and is under the working pressure of the fuel. The control space (36) is limited by the injection valve element (40) in the manner of a piston. The injection valve element (40) interacts with an injection valve seat (52) and is guided with slip fit via its end area, which faces the control space (36), in the needle guide (48) formed on the needle guide part (47). The needle guide part (47) is shaped onto the cylinder element (28). The pressure inside the control space (36) produces, over the piston surface (86), a force toward the actuator (18) that, however, is partially compensated for by the compensation surface (88). This permits the use of low-output actuators (18).

Fuel injection valve for combustion engines

The engine fuel injection valve has a housing (1) with an overflow channel (14) connected to the control chamber (4,7) The control side (15) of the overflow valve selectively locks an opening movement of the injector valve needle (2)

Fuel injection valve for internal combustion engine

A nozzle needle (4) is axially slidable between a stop and open position in the valve housing (9). In the stop position it is pressed against a nozzle needle seat (6) with injection ports (5) by a piston (5). A control chamber (2) is coupled to the valve (1) fuel inlet (7) via one or more closable ducts (14), with the control chamber pressure actuating the piston. Into a valve seat (15) in the control chamber opens an intermediate chamber (12), coupled to the fuel inlet and to the control chamber, which has an outflow port (10) closable by a servo-member (8). In the connecting line between the control and intermediate chambers is located a stop valve for the fuel flow to the control chamber.

Wolfgang Bloching

Papers

Intermittently acting IC engine fuel injection valve