JPS5882015A - Binary fuel internal-combustion engine - Google Patents

Abstract

PURPOSE:To start the internal-combustion engine positively by mounting a by- injection nozzle for by-fuel, which is easy to be self-ignited toward a glow plug at the lower stream side, at the stream side upper than the main injection nozzle of an air swirl flow in a by-chamber in case of a compression stroke. CONSTITUTION:The by-injection nozzle 09 is arranged at the upper stream side of the air swirl flow 10 higher than the main injection nozzle 03 of the by- chamber 01, and injects fuel having high self-ignition property in the direction of the glow plug 04, the direction of main fuel atomizing, before fuel having low self-ignition property, such as alcohol, etc. is injected from the main injection nozzle 03. Consequently, by-fuel is ignited by air compressed at a high temperature and at high pressure by means of a piston 07, and main fuel is injected in the direction of the swirl flow at that time. Accordingly, main fuel is also ignited stably. Since compression pressure does not rise sufficiently when starting, the glow plug 04 is conducted and heated, and ignition is assisted.

Description

[Detailed description of the invention] The present invention relates to dual fuel internal combustion engines.

Figure 1 shows the combustion chamber structure of a conventional pre-chamber diesel engine. In the figure, 01 is a swirl chamber, 02 is a combustion chamber mouthpiece, 0
3 is an injection nozzle, 04 is a glow plug, 05 is a communication port from the swirl chamber to the main combustion chamber, 06 is a cylinder head, 07 is a piston, and 08 is a cylinder liner.

In a swirl chamber type diesel engine, first the swirl chamber (auxiliary chamber) 01
A mixture is formed by the fuel supplied from the injection nozzle 03, and the piston 07 is heated to a high temperature.

Compression ignition with high pressure compressed air 1 base 02
Combustion gas is ejected from the communication port 05 into the main combustion chamber formed by the piston 07, cylinder liner 08, and cylinder Rad 06, and is converted into work by the movement of the piston 07. Further, a glow plug 07 is provided to assist in ignition at the time of starting. A fuel suitable for combustion in such an engine is a fuel with good self-ignition properties (relatively high cetane number).

However, fuels with poor self-ignition properties, such as alcohol fuels and liquefied coal oil, cannot be used as fuel in swirl chamber diesel engines.

The purpose of the present invention is to focus on the above points, and to develop a dual-fuel engine in a swirl chamber type diesel engine that uses a single fuel with low self-ignition property, it is possible to optimally use an auxiliary fuel as the most efficient ignition source. Our goal is to provide a dual fuel engine that can respond to the diversification of fuel supply conditions, and its features are:
In an auxiliary chamber type internal combustion engine, the main fuel is injected toward the glow plug, which is provided upstream of the air vortex generated by the compression stroke in the auxiliary chamber than the main injection nozzle that injects the main fuel, and which is downstream of the main injection nozzle. Another advantage is that it is equipped with an auxiliary injection nozzle that injects auxiliary fuel that is likely to self-ignite.

As a result, a stable ignition source can be set in the center of the subchamber, and when starting, the glow plug can heat and ignite the engine, allowing reliable starting.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a combustion chamber of a dual-fuel internal combustion engine according to the present invention.

In the figure, 01 is an auxiliary chamber, that is, a swirl chamber, 02 is a combustion chamber mouthpiece, 03 is an injection nozzle for main fuel, that is, a main injection nozzle,
04 is a glow plug, 05 is a communication port from the swirl chamber to the main combustion chamber, 06 is a cylinder head, 07 is a piston, and 08 is a cylinder liner.

09 is an injection nozzle for auxiliary fuel, that is, an auxiliary injection nozzle; 10
is the air vortex, and 11 is the injection direction of the main fuel.

Reference numeral 12 indicates the sub-fuel injection direction, and 13 indicates a line connecting the nozzle hole of the sub-injection nozzle o9 and the tip of the glow plug.

The functions and effects of the above configuration will be described.

The sub-injection nozzle 09 is disposed on the upstream side of the air vortex 10 as well as the main injection nozzle o3, and injects fuel with low self-ignition property (for example, alcohol fuel 1 and coal liquefied oil) into the main injection nozzle 0.
Prior to injecting from 3.

A fuel with relatively high self-ignition property is injected in the direction of the glow plug o4, that is, in the direction of the main fuel spray. By doing so, the auxiliary fuel, which has a relatively high self-ignition property, is ignited by the air compressed to high temperature and high pressure by the piston 07. Just around this time, the main fuel with low self-ignition property is injected from the main injection nozzle 03 in the vortex direction.

As a result, the auxiliary fuel spray flame ignited by the main fuel injection
The auxiliary fuel spray flame is formed in the center of the swirl chamber 01 so as to be in contact with the main fuel spray and to be surrounded by the main fuel spray, and serves as a stable ignition source for the main fuel spray without being affected by the combustion chamber wall surface.

When the main fuel spray flame is ignited by the secondary fuel spray flame, 1
Combustion gas is ejected from a communication port 05 of a mouthpiece 02 into a main combustion chamber consisting of a piston 07, a cylinder liner 08, and a cylinder head 06, and is converted into work by the movement of the piston 07.

Furthermore, at the time of startup, the engine speed does not rise enough, so the compression pressure does not rise enough, and even fuel with a high cetane number is difficult to self-ignite. Therefore, glow plug 04
It is energized and heated to help ignite. However, this is less effective if the fuel spray does not come in direct contact. Therefore, in order to ensure that the auxiliary fuel spray is ignited even during startup, the injection direction is directed to the outside of the auxiliary chamber 01 from the line 13 connecting the nozzle hole of the auxiliary injection nozzle and the tip of the glow plug, as shown by the arrow 12. Directly contact the glow plug 04 on the circumferential side.

An ignition nucleus is created, the main fuel is ignited using the same mechanism as described above, and the engine is started.

In the above case, a stable ignition source can be provided in the center of the subchamber, and reliable startup can be performed via the glow plug during startup.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a combustion chamber of a conventional pre-chamber type diesel engine, and FIG. 2 is a sectional view showing a combustion chamber of an embodiment according to the present invention. 01... Sub-chamber, 03... Main injection nozzle, 04...
Glow plug, 09...Sub-injection nozzle, 10...Air vortex. 11...Injection direction of main fuel, L2...Injection direction of auxiliary fuel.

Claims (1)

[Claims] 1. In a pre-chamber type internal combustion engine, the main injection nozzle that injects the main fuel is also provided upstream of the air vortex generated by the compression stroke in the pre-chamber, and the above-mentioned glow plug is provided downstream of the main injection nozzle. A dual-fuel internal combustion engine characterized by being equipped with an auxiliary injection nozzle that injects an auxiliary fuel that is more likely to self-ignite than the main fuel.