JPH02252957A - Fuel injector - Google Patents

Abstract

PURPOSE:To surely permit the self ignition of alcohol fuel in simple manners by connecting a feeding passage for ignition accelerating additive on the downstream side from the delivery valve of a fuel injection pump and connecting a unidirectional valve which is opened in a specific state and a solenoid valve in the above-described feeding passage. CONSTITUTION:Ignition accelerating ignition agent is supplied, together with alcohol fuel, into a fuel injection nozzle. When the self ignition of alcohol fuel is not surely carried out on the engine start, etc., a solenoid coil 42 is excited by a controller 44, and a solenoid valve 41 is opened. Further, a unidirectional valve 40 is intermittently opened by utilizing the negative pressure due to the pressure waves generated in a fuel injection pipe 15. Then, an ignition accelerating additive is allowed to flow into a fuel injection pipe 15 through a feeding pipe 43, solenoid valve 41, and the unidirectional valve 40 which are connected on the downstream side from the delivery valve 32 of a fuel injection pump. Therefore, the ignition accelerating additive is mixed with alcohol fuel if necessary, and sure ignition is achieved.

Description

[Detailed description of the invention] [Industrial application field]

SUMMARY OF THE INVENTION An adapter is connected to the downstream side of a delivery valve of a fuel injection pump that pressurizes alcohol fuel and supplies it to a fuel injection nozzle, and a one-way valve is connected to the adapter. A supply path for an ignition promoting additive is connected to the ignition promoting additive via a solenoid valve and a solenoid valve. When the solenoid valve is opened during startup, the one-way valve is opened by the negative pressure generated in the injection pipe, and the ignition accelerating additive is introduced into the injection pipe, mixed with alcohol fuel, and supplied to the fuel injection nozzle. This enables self-ignition operation of an alcohol engine and also eliminates the need for auxiliary ignition means such as a spark plug. K. Prior Art Diesel engines are widely used as a power source for commercial vehicles such as trucks and buses. In a diesel engine, fuel is pressurized by a fuel injection pump, and the pressurized fuel is injected into a cylinder by a fuel injection nozzle. The fuel spray is self-ignited by the heat of the air pressurized by the piston, thereby causing combustion. The disadvantage of such diesel engines is that the exhaust gas contains nitrogen oxides and black smoke, which causes air pollution. In order to overcome these drawbacks, attempts have been made to use alcohol fuel instead of light oil as fuel for diesel engines.

[Problems to be solved by the invention]

Diesel engines that use alcohol fuel instead of light oil do not necessarily self-ignite reliably, and there is a possibility of misfire. In other words, since alcohol fuel has inferior self-ignition properties compared to light oil, it has the disadvantage that reliable ignition cannot be achieved during startup or the like. Therefore, conventional alcohol engines are provided with auxiliary ignition means such as an assist plug. However, if a spark plug or the like is provided for auxiliary ignition, the cost of the engine increases. Therefore, it has been proposed to mix an ignition promoting additive into alcohol fuel. By using such additives, self-ignition operation is always possible regardless of the engine condition. However, since the ignition promoting additive itself is expensive, when such an additive is used in combination with alcohol, a problem arises in that running costs become high. The present invention has been made in view of such problems, and an object of the present invention is to provide a fuel injection device that does not use an assist plug for auxiliary ignition and uses a minimum amount of additive for promoting ignition. The purpose is to

[Means to solve the problem]

The present invention provides an apparatus in which fuel is pressurized by a fuel injection pump, the pressurized fuel is supplied to a fuel injection nozzle, and the fuel is injected from a nozzle of the fuel injection nozzle, in which a delivery valve of the fuel injection pump is provided. A one-way valve and a solenoid valve that are opened when the pressure on the fuel supply path side to the fuel injection nozzle is low are connected to the downstream side of the ignition promoting additive. It is connected to the agent supply path. K effect] Therefore, if you open the solenoid valve when there is a possibility that self-ignition may not be successful, such as during startup, the one-way valve will open when the pressure in the fuel injection system downstream of the delivery valve becomes negative. As a result, the ignition promoting additive is mixed into the fuel and supplied to the fuel injection nozzle, thereby making it possible to achieve reliable self-ignition.

【Example】

FIG. 2 shows a fuel injection pump 10 according to an embodiment of the present invention, and this fuel injection pump 10 is used, for example, in a diesel engine for a truck. The fuel injection pump 10 includes a mechanical governor 11, which moves a control rack 12 to adjust the amount of fuel injected by each pump unit at one time. Further, the fuel injection pump 10 is provided with a camshaft 13, and a timer 14 is attached to this camshaft 13. The timer 14 adjusts the injection timing of the fuel injection pump 10 to an appropriate value by adjusting the phase angle of the camshaft 13. FIG. 3 shows the structure of each pump unit of the fuel injection pump 10. A cam 17 is fixed to the camshaft 13, and this cam 17 connects a tappet 19 attached to the lower end of the plunger 18. It is designed to be pressed. The plunger 18 is pressed downward by a coil spring 20 and is supported within the barrel 21 so as to be movable in the axial and rotational directions. Further, the barrel 21 is provided with a spill boat 22, and when the outer peripheral surface of the plunger 18 closes this boat 22, pressure feeding of fuel is started. Furthermore, an inclined groove 23 is formed in the plunger 18, so that the amount of fuel supplied can be adjusted. Control rack 12 is adapted to be engaged with binion 26. The pinion 26 is fixed to a control sleeve 27, and a notch 28 is formed at the lower end of the control sleeve 27. The notch 28 is adapted to be engaged with an engagement plate 29 attached to the lower end of the plunger 18. Next, the structure of the delivery valve 32 provided at the upper part of the barrel 21 will be explained. As particularly shown in an enlarged view in FIG. 1, the delivery valve 32 is held within a casing 33, and the valve seat 34
It is urged downward by a coil spring 35 so that it is crimped to the bottom. Further, the delivery valve 32 is integrally provided with a suction/return valve 36 at its lower part. Casing 33 holding the delivery valve 32
As shown in FIG. 1, an adapter 39 is connected to the upper end of the adapter. The adapter 39 is equipped with a one-way valve 40. This one-way valve 40 is opened when the pressure within the injection pipe 15 on the downstream side of the delivery valve 32 becomes negative pressure. Furthermore, the adapter 39 has a solenoid valve 41.
is connected. This solenoid valve 41 is equipped with a solenoid coil 42, and when excited by a signal from a controller 44, this solenoid valve 41 is opened. An ignition promoting additive supply pipe 43 is connected to the solenoid valve 41. Next, the operation of each pump unit of the fuel injection pump 10 will be explained with reference to FIG.
Push up. Then, the plunger 18 moves upward within the barrel 21, and its upper end closes the spill boat 22, thereby pressurizing the fuel within the barrel 21. The pressurized fuel pushes up the delivery valve 32 against the coil spring 35 and forces the fuel upward, which causes it to flow into the engine 10 through the injection pipe 15 shown in FIG.
Fuel is supplied to the fuel injection nozzle 16 provided in each cylinder. Since the inclined groove 23 provided in the plunger 18 is in communication with its center hole, when the inclined groove 23 is aligned with the spill boat 22, at this point the fuel pressure suddenly leaks to the spill boat 22 side. is stopped, and the delivery valve 32 is closed by the elastic restoring force of the spring 35. When the control rack 12 is moved along its length, the pinion 26 is rotated. And this Binion 26
The rotational movement of the plunger 1, which has an engagement plate 29 that engages with a notch 28 thereof, is controlled via a control sleeve 27.
8. Therefore, the plunger 18 rotates within the barrel 21, and the inclined groove 23 also moves in the circumferential direction. Such circumferential movement of the inclined groove 23 changes the position of the inclined groove 23 that aligns with the spill boat 22, thereby changing the effective stroke of the plunger 18. In this way, the amount of fuel injected by the fuel injection pump 10 is adjusted. Next, the operation of supplying the alcohol fuel and the ignition promoting additive to the fuel injection nozzle 16 will be explained. For example, when self-ignition of alcohol fuel is not necessarily performed reliably, such as at the time of starting, a signal is supplied from the controller 44 to excite the solenoid coil 42. Then, the solenoid valve 41 is opened by the coil 42. Moreover, when the first langeer 18 of the fuel injection pump 10 periodically pressurizes the fuel, pulsation occurs in the injection pipe 15 connected between the fuel injection pump 10 and the fuel injection nozzle 16, and negative energy is generated due to pressure waves. Pressure is generated. This negative pressure causes the one-way valve 40 to open intermittently. Therefore, the ignition promoting additive supply pipe 43, the solenoid valve 41,
The ignition promoting additive is then flowed into the injection pipe 15 through the one-way valve 40. This ignition promoting additive is mixed with alcohol fuel pressurized by the fuel injection pump 10, and the alcohol fuel mixed with the additive is injected into the cylinder by the fuel injection nozzle 16,
It will burn by self-ignition. When the engine 10 has sufficiently warmed up and becomes capable of self-ignition operation using only alcohol fuel, the controller 44 detects this using a sensor (not shown) and supplies a signal to close the solenoid valve 41. This causes the supply of the ignition promoting additive to stop. According to such an engine, an ignition accelerating additive is mixed with alcohol fuel as needed and the mixture is injected into the fuel injection nozzle 16.
Since the fuel can be injected directly, auxiliary ignition means such as spark plugs are no longer required. Further, the additive is supplied only when the solenoid valve 41 is opened, and the opening and closing of the solenoid valve 41 is controlled by the controller 44. Therefore, the ignition accelerating additive is used only in limited operating conditions, and the amount of expensive ignition accelerating additive used is extremely small, resulting in lower running costs and economical operation. becomes possible. [Effects of the Invention] As described above, the present invention connects the supply path of the ignition accelerating additive to the downstream side of the delivery valve of the fuel injection pump, and when the pressure on the side of the fuel supply path to the fuel injection nozzle is low. A one-way valve and a solenoid valve that are opened are connected to a supply path for an ignition promoting additive. Therefore, by opening the solenoid valve only when there is a possibility that combustion by self-ignition will not occur reliably, the ignition promoting additive is sucked in by the negative pressure that is periodically generated downstream of the delivery valve of the fuel injection pump. , and will be mixed with fuel and supplied to the fuel injection nozzle. This makes it possible to supply the ignition promoting additive only when needed, and eliminates the need for auxiliary ignition means such as a spark plug.・Solenoid valve ・Solenoid coil ・Additive supply pipe for ignition promotion ・Controller

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a fuel injection device according to an embodiment of the present invention, FIG. 2 is a front view showing the overall configuration of a fuel injection pump, and FIG. 3 is an internal structure of a pump unit of the fuel injection pump. It is a partially broken perspective view showing the. The names of the main parts in the drawings are as follows. 10...Fuel injection pump 15...Injection pipe 16...Fuel injection nozzle 18...Plunger 32...Delivery valve 39...Adapter 40...One-way valve

Claims (1)

[Claims] 1. In an apparatus in which fuel is pressurized by a fuel injection pump, the pressurized fuel is supplied to a fuel injection nozzle, and the fuel is injected from a nozzle of the fuel injection nozzle, the fuel injection pump is downstream of a delivery valve of the fuel injection pump. A one-way valve and a solenoid valve that are opened when the pressure on the side of the fuel supply path to the fuel injection nozzle is low are connected to the supply path for the ignition promoting additive. A fuel injection device characterized by being connected to.