JPH03160150A - Compression ignition internal combustion engine and injection valve thereof - Google Patents

Abstract

PURPOSE:To enhance thermal efficiency by improving the combustibility by variably controlling a lift of a pin type needle valve in accordance with a combustion supply amount and restricting fuel injection by a relative relation between a pin shape and a nozzle shape with a fuel group set in a diffusion direction, at the time of a low load, and in a binding direction at the time of a high load. CONSTITUTION:A rod 4 for controlling a lift amount of a needle valve is arranged in the spring 2 of a nozzle holder 1 in a fuel injection nozzle. One end part 5 of this rod 4 is brought into contact with an eccentric cam 6 through a spacer 7 with a position of the rod 4 made variable by actuating the eccentric cam 6. The eccentric cam 6 is actuated by an electrically operated mechanism 8 or a hydraulically operated mechanism. In a correlation between a needle throttle position 3 and a nozzle flow path 10, throttle action is changed and/or diffusing direction of fuel injection is restricted. That is, a fuel group is set in a diffusing direction, at the time of a low load, and set in a binding direction at the time of a high load.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a compression ignition internal combustion engine and a fuel injection valve. [Prior Art] A conventional fuel injection nozzle closes a needle valve using spring pressure. The main type of valves are automatic valves that open according to the pressure of supplied fuel (valve opening pressure).

Therefore, when a small amount of fuel is supplied, such as when the engine is idling or under low load, the needle lift will inevitably not reach the stopper position, but will be located somewhere in between, and the position will depend on the spring constant and fuel pressure. The stopping position tends to become unstable due to the equilibrium with the

Therefore, irregular injection often occurs at low speeds, etc., and the atomization, permeability, and dispersion of the fuel group tend to be worse than when the load is high, which is considered a problem. Further, during operation, the fuel group injected from the nozzle holes is characterized in that atomization is promoted by the evaporation effect due to heating. It is nearly impossible to grasp the actual effects of fuel diffusion, customization, atomization, etc. that are affected by such thermal conditions, and this can be said to be the reason for hindering the development of diesel combustion technology and exhaust gas countermeasure technology.

For nozzles that are greatly affected by heat in this way, the problem of white smoke/blue smoke during startup and the like and the problem of black smoke generation during high loads are two sides of the same coin, and it is difficult to avoid them. This problem is also a common improvement issue for multi-hole automatic valves and single-hole pin type valves.

[Problem S that the invention attempts to solve]

It is known that the performance of the direct injection system, which achieves efficient combustion by matching the diffused fuel group and air swirl using a multi-hole valve, varies greatly depending on the fuel spray state.

This method has contradictory characteristics such as deterioration of inertia if the fuel particles are atomized, and it is an absolute requirement that the swirl be adapted to the rotational speed. Moreover, the device that generates the swirl inevitably creates resistance in the air supply flow path, which is a disadvantage. Recently, research has been carried out on solutions using ultra-high pressure injection systems as a means of solving these problems, but ultra-high pressure devices have many disadvantages in terms of cost, durability, power consumption, etc., and are not practical. raises difficult questions.

The inventor previously proposed a fuel jet impingement diffusion combustion method using a single-hole nozzle as a means of solving these problems with direct injection engines (SA] +4871689, fsAI & 8812
41). This method uses a single-hole pin-shaped nozzle to obtain higher thermal efficiency and higher output than the conventional WArJR in non-high-pressure injection, and also has a short combustion period because the combustion reaction occurs near the fuel collision part in the center area of the combustion chamber. has been proven. However, when the above combustion method is used with a conventional pin-type nozzle, that is, the valve opening pressure is set by spring pressure, the needle valve lift depends on a mechanical stopper action, and the injection supply is performed by the feed position and feed speed etc. from the fuel pump. is greatly affected by the spring constant, and the degree of lift of the needle valve becomes unstable depending on the amount of fuel fed, and especially in multi-cylinder engines, this change causes uneven combustion in each cylinder. Further, when idling operation with low combustion temperature is continued for a long time, there is a problem that the collision surface temperature decreases and carbon adheres to the collision surface.

[Means to solve the problem]

The present invention is a pin type injection valve that controls the needle lift according to the fuel supply amount, changes the throttle action according to the load, and changes the atomization of fuel particles and the diffusion angle etc. by the throttle action according to the load. Therefore, when the load is low, the atomization conditions are promoted and effective combustion is achieved without relying on heat or collision effects. For this reason, by suppressing the lift and increasing the throttle action in the pin-type throttle valve, the atomization of the fuel is promoted at low loads, and the fuel is dispersed in a disk shape starting from the nozzle hole, thereby shortening the combustion period. Ru. In this case, there is no need to rely on collision effects for fuel diffusion. Also, under high loads, the throttle action is reduced and the opening area is increased.
By converting all the fuel into a rigid jet within a short period of time, retaining the flow energy and colliding with the high-temperature collision part, diffusion and acclimatization time can be shortened. Therefore, even with relatively low injection pressure, it is possible to improve output performance, fuel efficiency, smoke, etc. over the entire load range.

〔Example〕

Embodiments of the invention are explained in the drawings.

In Fig. 1, the spring (2) of the nozzle holder (1) contains a rond for controlling the lift claw of the eddle valve (3).
is in place. One end 6) of the mouth rod (4) is in contact with an eccentric cam (6) via a spacer (7), and is configured such that the position of the rond (4) moves with the operation of the cam (6). There is. The cam (6) is operated by an electric actuating mechanism (8) or a hydraulic actuating mechanism 111 (9) as shown in Fig. 20 and Fig. 3.
) is carried out by The needle lift can also be controlled by moving the wedge mechanism as shown in FIG. Therefore, as shown in FIGS. 5, 6, 7, and 8, it is necessary to change the throttling action in the relationship between the needle throttle position (3) and the nozzle hole flow path (10).
As a result, atomization of the fuel is promoted even during idling or low load.

Furthermore, Figures 9 and 10 show an example in which this technology is applied to a collision-diffusion diesel system. In this case, by limiting the lift, the fuel collides with the collision surface less during idling or low load as shown in Figure 9, and the collision effect of the fuel group occurs only at high load as shown in Figure 10. Even in the case of polishing at a temperature of the collision surface at different times, problems such as carbon accumulation on the collision surface do not occur. In engines with a large combustion bed, such as the Genta Poiku, by moving the needle valve lift, it is easy to move the flame area within the large bed and equalize the combustion state. It is possible to improve durability and heat transfer efficiency, and reduce exhaust pollution.

〔Effect of the invention〕

According to the present invention: 1. In the diesel combustion system, by intentionally increasing the throttle action during idling or low load, fuel diffusion and atomization are promoted, improving combustion in the low load range. Therefore, compared to conventional engines, unburned hydrocarbons are reduced, and the problems of odor and white smoke are improved.

1. The ignition delay phenomenon is shortened by the fuel particle promotion effect at low loads and by the temperature effect at the collision part at high loads, and as a result, the noise caused by the ignition delay is reduced.

1. The nozzle area expansion effect under high load is advantageous in suppressing atomization of the fuel flow and retaining energy until the fuel flow reaches the collision surface, even at conventional pump pressures of 150 to 300 kg/m, and the collision diffusion effect is effective. At the same time, an ideal diffusion flame is formed from the center of the combustion chamber due to the high temperature ignition promoting effect of the collision part. The reaction of this diffusion flame rapidly progresses in the radial axial flow due to the cylinder air moving into the combustion chamber (skitsch flow), resulting in a shortened combustion period.

1. Thermal efficiency is improved by shortening the combustion period, and there is little reduction in thermal efficiency even in KGB/late injection. NOx is significantly reduced compared to conventional direct injection systems.

1- In this internal combustion engine that does not require swirl,
The air supply system is simple and has low resistance, which is advantageous for the volumetric efficiency of air supply, and is highly effective in improving engine specific output.

[Brief explanation of the drawing]

The drawings show examples of the present invention, and include FIGS. 1, 2, and 2.
Figures 3 and 4 show an example of a Kel needle valve lift control method for a pin type nozzle. 5, FIG. 6, FIG. 7, and FIG. 8 are enlarged cross-sectional explanatory views of the vicinity of the nozzle hole of the pin-type nozzle, and FIGS. 6 and 7 are examples of having small notches of vI number in the throttle part,
Figures 9 and 10 are explanatory diagrams in which the present invention is implemented in a collision-diffusion type diesel engine. Figure 9 shows the trend of the fuel group at low load with a small needle lift, and Figure 10 shows the trend of the fuel group at a low load with a small needle lift. The collision-diffusion effect of fuel groups and flame development trends are shown under high loads. In the figure, 1-/Zulu body, 2-- Closing spring, 3-- Needle valve throttle part, 4-- Lift control rod, 5--
... Rod end, 6... Cam, 7 - Baser, 8
1. Electrical actuation mechanism, 91. Hydraulic actuation mechanism, 101. Nozzle hole flow path, 11.. Diffusion flame at idle, 12.. Diffusion flame at high load. 13. Trend of skitsch flow. . Figure 2

Claims (1)

[Claims] 1. The lifting height of the pin-shaped needle valve is variably controlled according to the amount of fuel supplied, and the relative relationship between the pin shape and the nozzle hole shape causes the fuel group to spread in the direction of diffusion at low loads and to bundle at high loads. A compression ignition internal combustion engine characterized by a direction. 2. The injection valve according to claim 1, wherein the injection hole portion is formed in an inwardly expanding taper shape. 3. The injection valve according to claims 1 and 2, characterized in that the throttle portion has a conical tip and a plurality of small cut portions with equal gaps. 4. The injection valve according to claim 1, characterized in that a variable lift mechanism is constructed within the solenoid valve that opens the needle valve.