JPS62139921A - Fuel collision, reflection, and diffusion type combustion method and internal combustion engine therefor - Google Patents

Abstract

PURPOSE:To improve an air utilization factor and shorten combustion time by providing the piston of an internal combustion engine with a fuel collision and reflection plate and by injecting the fuel jet from a fuel injection nozzle to a piston surface or into a cavity. CONSTITUTION:The diffusion 3 of the jet 2 from a fuel injection nozzle 1 due to collision and reflection causes fuel particles to reach throughout a cavity by means of a squish flow 4. A main flow is forced to distribute to the upper opening 5 of the cavity so as to effectively utilize the air in a peripheral area, and the cavity central section in a jet collision area is to be a projection 6 of which volume is reduce by that effective to a heat pinch scheme. A jet colli sion section 7 makes the fuel particles diffused in the peripheral area diffuse throughout three-dimentionally. Combustion time is thus shorten improving fuel consumption and minimizing the production of NOX.

Description

[Detailed Description of the Invention] At present, it has not been possible to make a direct injection diesel engine smaller and faster, which is advantageous in terms of fuel economy, and the reason for this is that it is difficult to miniaturize the fuel injection nozzle (multi-hole needle valve body). Since the porous hole nozzle is sensitive to heat, it is necessary to match it with a single swirl in order to obtain the optimum combustion conditions, and with the current method, it is extremely difficult to speed up and downsize due to the constraints on combustion. Although there is no problem with the nozzle in the M combustion system, since the evaporation of the fuel on the cavity wall is the main element for generating the air-fuel mixture, this also has the problem that it is not possible to increase the speed of combustion.

The present invention uses a single-hole nozzle with self-cleaning properties to intentionally perform synthetic combustion of diffusion threat evaporation and premixing through the collision and reflection effect of fuel jets, thereby making it possible to reduce dust and increase speed of direct injection diesel engines. This paper relates to diesel combustion system technology, combustion technology for fuel-injected multi-fuel engines, and technology for stratified air premixing engines.

A major drawback of the needle valve type multi-hole nozzle, which is most commonly used in direct injection systems, is that the state of the injection r4 changes significantly due to the influence of heat.

For example, when the nozzle tip temperature is relatively low, the penetration of the fuel is large, and the spray tip collides with the cavity wall, resulting in a large local cooling effect, which causes an over-concentrated area and white smoke. W occurs. In addition, when the nozzle tip temperature increases, the atomization diffusion progresses to an extreme degree and the penetration becomes weaker. This causes excessive diffusion combustion near the nozzle, so an appropriate swirl is required. It is still an unresolved problem to control the temperature of y, and the conditions such as the number of pores, pore diameter, heating, etc. for fuel diffusion and atomization are all dependent on the polymer content in the fuel. It also promotes clogging of the holes due to polymerization, and the air utilization rate decreases due to the deflection of the spray, generating black smoke and worsening fuel efficiency. These problems have become more and more serious as engines become smaller, and have become a major barrier to the miniaturization and higher speed of direct injection diesel engines, which are advantageous in terms of thermal efficiency.

In other types of direct injection systems, such as the M combustion system, it is possible to use a single hole valve for the nozzle, but the main means of generating air-fuel mixture relies on evaporation on the wall surface of the piston recess.
This method cannot be expected to increase the speed of the engine, and on the other hand, studies have been published on combustion systems that use swirl injection valves, which are characterized by large spray angles and low spray penetration, and are mainly based on diffusive combustion. However, this combustion system still does not satisfy high speed, and the piston cavity must be formed deep in this combustion system.
The upper structure is higher than the piston pin and the engine body 41
This creates conditions that are inconvenient for light corrosion and miniaturization of the engine, such as the structure becoming larger.

The present invention, as a means to solve the above-mentioned problems, uses a single-hole nozzle such as a pintle or throttle, which has a self-cleaning effect and is highly stable against heat, and directs the fuel jet into the cavity or onto the piston surface. By colliding and reflecting the fuel jet, the fuel particles are subdivided and atomized three-dimensionally within the cavity, and by utilizing the penetrating properties of different particles, a stirred surface evaporator with relatively large fuel particles is created. By performing synthetic combustion of mixed combustion and diffusion combustion using fine particles at multiple points within the cavity in a short time, the combustion reaction speed is increased, the air utilization rate is increased, and combustion with reduced swirl dependence is achieved. The purpose of this is to reduce the size and speed of direct injection diesel engines, which are advantageous in thermal efficiency. Another purpose is to reduce the size and speed of direct injection diesel engines, which are advantageous in thermal efficiency. The fuel is atomized and diffused by colliding it with the top surface and utilizing the injection effect caused by the collision, and by ensuring the formation of a premixture throughout the entire combustion chamber, it is possible to form a premixture that is effective when using a variety of fuels. The purpose is to present the technology.

Still another object of the present invention is to utilize the penetrating property of a single hole nozzle,
The purpose is to inject and supply fuel to four parts of the piston surface relative to the nozzle to create a mixture ratio range within the recess where ignition is possible by spark ignition, and to perform stratified combustion using lean stratified air supply in the cylinder as a whole.

An embodiment of the combustion system according to the present invention will be described below with reference to the drawings.

In the compression ignition system, as shown in Figures 1 and 2, it is advantageous for the cavity shape to be as shallow as possible from the design point of view of downsizing the engine. The fuel particles are diffused (3) by the squish flow (4) and reach the entire cavity area, and the main flow is distributed to the cavity upper opening (5) in order to effectively utilize the surrounding air, and the cavity in the jet impingement area is The center part has a high-bottom shape (6) with a reduced volume that is effective for thermal pinch measures, and the jet collision part (the sword is a truncated concave surface or a three-dimensional spray dispersion around the cavity and a spray opposite to the squish flow). In order to effectively perform both the diffusion and diffusion effects, the truncated concave surface of the collision part is formed into a polygonal shape with different spherical radii as shown in FIGS. 3 and 4. It has the effect of three-dimensionally dispersing the diffusing fuel particles throughout the cavity, and by fractionating fuel particles that are highly penetrating and reach the peripheral wall at multiple points, premixing due to evaporation can be reduced in a short time. Compared to conventional combustion methods, the generation of flame kernels is promoted three-dimensionally and at multiple points throughout the circumference, and the reaction time for the entire cylinder is shortened.

It is obvious that the degree of swirl dependence is naturally reduced by these measures.

Swirl is an important condition for the multi-hole type, which is the mainstream of conventional direct injection engines.To generate this, the shape of the intake passage has been devised, and the swirl of the air supply flow has been created using methods such as directional and helical. However, all of these increase the resistance of the air supply system, and the engine! & The pile abandonment force and smoke generation limits are becoming more restricted, and the same applies to the installation of guide walls on valves (shroud valves).

In such a combustion system according to the present invention, fuel is diffused in opposition to the squish flow, and mixing with air is achieved by multi-angular three-dimensional fuel distribution within the cavity and heat transfer and evaporation action across the peripheral wall. The fine particulates in the fuel spray shift to a diffusion combustion reaction at g & speed, and the relatively large particles diffuse into the surrounding area due to the condition of high penetration, and some of them are absorbed before reaching the wall surface. In addition, the fuel that reacts to the wall surface and reaches the wall surface is dispersed at multiple points and over a wide range compared to the hole type, so evaporation progresses rapidly at each reaching point. In conventional combustion methods using multi-holes and nozzles, the fuel spray reaches the wall surface and concentrates in a specific location determined by the number of holes and the direction of the holes. It is well known that a rich air-fuel mixture region is unavoidable and that appropriate swirling motion is required. Recently, it has been found that the intensity of swirl promotes the generation of Mox, and control of swirl has become an important issue in improving the performance of diesel engines.

In the present invention, the jet flow from the nozzle is not diffused in the center region of the cavity, which is susceptible to thermal pinch, and the energy is conserved so that it reaches the cavity collision part in a rigid body, and the fuel is reflected and diffused from this collision part as a starting point. Since the purpose is achieved by single-hole nozzles such as pintles and throttles with small spray angles, it is a great effect of the present invention that the troubles caused by nozzles, which have often occurred in the past, are clearly resolved. .

In addition, the fuel jet that collides with this rigid protrusion in the cavity conserves its flow energy, and the jet is split by collision reflection and effectively dispersed to the outer area in order to ensure that the fuel is distributed to the entire circumference area. In order to achieve the distribution conditions, it is effective to keep the temperature of the collision part within a certain range, but in this respect, the temperature control of the collision part installed in the piston cavity or the top surface of the piston is also effective because cooling from the bottom surface of the piston is not effective. This can be easily done by

In addition, this method can easily ensure premixing with air by advancing the injection timing not only in diesel systems but also in premixed spark ignition combustion systems that use liquid fuels other than diesel fuel such as gasoline, kerosene, and methanol. Since the air utilization rate can be increased with less dependence on swirl, it is advantageous as a multi-fuel engine.

In this way, in the diesel system, the spray angle is small and the jet is dispersed and diffused by collision and reflection inside the cavity, creating a three-dimensional mixture inside the cavity. The feature of the present invention is that even as a spark ignition multi-M4 fuel engine, there is a margin in the generation of premixture, and sufficient vaporization and premixing can be performed. Compared to a diesel engine, an injection type multi-fuel engine, or a spark ignition type premix engine, it has many effects and advantages as follows.

That is: (1) The three-dimensional, multi-directional, multi-point ignition combustion system shortens the combustion time, thereby making it possible to increase the speed of the engine, improving fuel efficiency, and generating less NOx.

■ By using single-hole nozzles with a large self-cleaning effect on pintles, throttles, etc., nozzle troubles are eliminated, and no black smoke is generated due to mist deflection or clogging, and there is no reduction in fuel efficiency or output. ■ Since there is little dependence on swirl, there is no need for flow circuits or shroud valves for swirl generation in the air supply path, so air supply efficiency is improved with a simple air supply path with low resistance, and output and smoke generation limits are reduced. Improved ■ Durability of the nozzle has been improved, maintenance and reliability of the engine as a whole have improved, and ■ It has become possible to downsize the engine.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a diesel engine. FIG. 2 is an RIJR plane view showing the state of fuel diffusion due to collision within the cavity. 3 and 4 are a three-dimensional view and a sectional view showing an example of a fuel collision reflecting concave surface having a spherical R surface, and FIG. 5 is a longitudinal sectional view showing an example applied to a fuel injection multi-fuel spark ignition engine. be. (N, (B), (0), and () in FIG. 6 are vertical cross-sectional views showing examples of the shapes of fuel collision parts, respectively. Figure 7 is a vertical cross-sectional view showing an example of a stratified air supply engine using fuel injection collision diffusion. 8 is a cross-sectional view showing the state of fuel distribution due to collision reflection and diffusion. In the figure, (1)...Fuel injection nozzle, (2)...Fuel jet, (5)...Diffusion fuel section, (4)...squish flow, (5)--cavity mouth, (6)...
-Fuel collision reflecting surface base, (7')...Jet flow collision part or surface, (8), -...Piston, (9)...Air supply valve, (
10)...Exhaust valve, (11)...Spark plug. Figure 1

Claims (6)

[Claims] (1) The fuel jet from the nozzle is injected and collided with the piston surface or inside the cavity, and by the reflection and diffusion effect on the collision surface, the fuel is diffused and mixed throughout the cavity starting from the collision part, reducing dependence on swirl. A collision-reflection diffusion combustion method for diesel engines, which is characterized by increasing air utilization efficiency and shortening the combustion period mainly by means of a squishy flow. (2) Using a pintle, throttle, or needle-valve single-hole nozzle, a fuel jet is caused to collide with the top surface of the piston or a convex or concave surface provided in the cavity, and three-dimensional fuel diffusion is achieved by the collision reaction within the combustion chamber. , a spark-ignition multi-fuel internal combustion engine characterized by promoting fuel mixture vaporization without relying on air flow energy. (3) Claim 1 characterized in that a convex portion having a fuel collision reflection surface for causing the fuel jet from the nozzle to collide with the bottom of the cavity is formed, and the collision surface shape is formed in a concave shape. ) Diesel engines listed. (4) The scope of the above-mentioned claim (
2) The spark-ignition premix combustion internal combustion engine described above. (5) The fuel jet from the nozzle collides with the recess provided in the opposing piston, and due to collision diffusion, a mixture region where spark ignition can ignite is formed in the recess.The stratified air supply creates a lean stratified combustion throughout the cylinder. A spark ignition stratified air supply internal combustion engine characterized by: (6) The collision part for diffusing and distributing the fuel jet from the nozzle by collision reflection is formed of a heat-resistant and wear-resistant material such as ceramic, and is mounted on the top surface of the piston or inside the cavity. An internal combustion engine according to claims (1) and (2) above.