JPS59180067A - Multiple ignition device for two-cycle engine - Google Patents

Abstract

PURPOSE:To improve the output and the accelerating property of the engine and permit to reduce fuel consumption by a method wherein ignition plugs are arranged at the central part of a combustion chamber and near a suction port so as to combine at least two limited ignitions. CONSTITUTION:The ignition plug 7 is attached to the central part S of the combustion chamber 6a of a cylinder head 6 and the ignition plugs 8, 9, 10 are provided radially surrounding the central part. The plug 8 is arranged in the suction port A on a horizontal line connecting the suction port and an exhaust port while the plugs 9, 10 are arranged at positions B, D on an axial line orthogonal to the horizontal line. According to this arrangement, the plug at the central part S improves the fuel consumption with respect to a vehicle speed the best and the plugs at the suction port A as well as the part B improve the same a little while the plug in the exhaust port C does not improve the same. In case of combination ignition, the output and the accelerating property of the engine may be improved and the fuel consumption may be reduced when the plug at the central part S is combined with at least on of the plugs at the parts A, B, D. Especially, the combination of S and A is effective. The combination with the plug in the exhaust port C has no effect and it introduces high cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-ignition system for a two-stroke engine, which improves engine performance by attaching spark plugs with a number of pJ among four internal combustion engines.

As a means to improve the ignition performance of internal combustion inspection and achieve fuel efficiency, it is often effective to make the ignition part of a spark plug protrude as much as possible into the combustion chamber and widen the spark gap. Although this is known, this alone is not sufficient to satisfy the purpose. On the engine side, on the other hand, the effect of advancing the ignition angle is great, but advancing the advance angle is accompanied by the occurrence of knocking and is likely to induce spark plug pre-ignition, which is undesirable. This had the drawback of significantly increasing costs.

It is also known to provide an internal combustion engine with a plurality of spark plugs to speed up flame propagation and improve ignition performance. However, the present inventors have discovered that in a two-stroke engine, the installation position of the spark plug affects the output and acceleration, and that by adjusting the installation position of the spark plug advantageously, the effect of reducing fuel consumption can be easily obtained. This is what we discovered.

In view of this, the present invention provides a combination of at least two ignitions that limit one spark plug to the central part of the combustion chamber of the cylinder head and the vicinity of the suction hole, thereby improving output and acceleration and greatly reducing fuel consumption. The purpose is to provide a multi-ignition device for a two-stroke engine that can reduce the amount of fuel used.

Hereinafter, the present invention will be explained with reference to the embodiments shown in the drawings. Figures 1 and 2 show the main parts of a single-cylinder two-stroke engine used in the embodiments of the present invention. In Figure 1, 1 indicates the cylinder. The ax block 2 communicates with a carburetor and a crank chamber (not shown) through a suction hole provided in the cylinder block.

3 is an exhaust hole, 4 is a piston, and 5 is a piston ring. A cylinder head 6 is provided with a hemispherical combustion chamber 6a between it and the piston. 7.8 and 9.10 are spark plugs.

They are screwed into the cylinder head 6 with threads or mounting holes exposed inside the combustion chamber 6a.

As shown in FIG. 2, these spark plugs include a spark plug 7 attached to a substantially central portion S of a combustion chamber 6a of a cylinder head 6, and spark plugs 8, 9, and 10 radially surrounding the central portion. It is installed. The spark plug 8 is located at the intake hole part A on the horizontal line connecting the intake hole and the exhaust hole.
To.

9 and lO are B and D on the ring center line that is perpendicular to the horizontal line.
It is located in In addition, on the side of the cylinder block where B and D are located, there is a scavenging hole for mixing intake air.The dotted line C indicates the exhaust hole for installing the spark plug used in the experiment. It is.

Next, the mounting position of the spark plug of the present invention and the development of an advantageous ignition combination will be described using experimental results.

The experiment was conducted using an actual vehicle with a 120cc cylinder, and as shown in Fig. 2, the spark plug (88EM spark gap 0.9cm) was set at each position S, At 1'3. C and D were installed and one performance evaluation was conducted.

(1) Regarding the influence of the installation position of the spark plug, as shown in Figure 3, the fuel efficiency with respect to vehicle speed is the best in the central part S (the first is the intake hole part A and B, and the worst in the exhaust hole part C). (Not effective.

(2) The result of appreciating the performance when igniting with various combinations of the spark plug positions, the central part S of the combustion chamber and the suction hole part A.
, B, and D (combined with one location) is effective for improving output and acceleration and reducing fuel consumption, especially for central hole S.
The combination of and suction hole portion A is effective. Note that the combination with the exhaust hole portion C has almost no effect, and the cost increases as the number increases.

In Figures 4 and 5, the central part S, S+A, S+A+B+D
, S+A+B and C+D, the output (60VH and 80
K/H) and acceleration (throttle A from/H to 40
(acceleration). Note that if a spark plug is attached to the entire spark plug including the exhaust hole portion C, the output will decrease on the advance side of one ignition advance.

Figure 6 shows the fuel economy performance of a combination of two or more ignitions.Compared to a single ignition in the center S, there are five ignition points in the case of a combination of the center S and suction holes A, B, and D. It is not possible to obtain performance close to all ignitions at the same time.

In addition, performance was evaluated by igniting all the two or more ignitions used in the experiment at the same time, but simultaneous ignition is not necessarily necessary.
The ignition timing of the ignition plug 5 in the radial peripheral portion may be slightly shifted from that in the central portion.

As described above (11), the multiple ignition system for the two-stroke engine of the present invention has one spark plug, or a combination of 11 spark plugs, one in the center of the combustion chamber of the cylinder head, and one in the suction hole surrounding the center. It is possible to improve fuel efficiency, output, and speed, and achieve a significant reduction in fuel consumption compared to conventional engines.Also, since a two-stroke engine does not have a valve mechanism, it is easy to install multiple spark plugs, and Since the coil can be used as an additional spark plug instead of the conventional one, it is possible to improve the performance of the two-stroke engine without increasing the overall cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the essential parts of a two-stroke engine showing an embodiment of the invention, Fig. 2 is a plan view of the E-cut of Fig. i1, and Figs. 3 to 6 show experimental results. Fig. 3 shows the fuel efficiency custom made for each mounting position for single ignition, and Figs. 4 to 6 show the output, acceleration, and fuel efficiency characteristics for multiple ignition. 6- 6... Nlinder head, 6a old... combustion chamber. 7.8, 9.10... Spark plug, S... Group...
Central part - A, B, D... Suction hole part Patent applicant: NGK Spark Plug Co., Ltd. 7 - Ml Figure 2 - Sales force. -IE R color- Diagram

Claims (1)

[Claims] (1) In a two-stroke engine that is equipped with a plurality of spark plugs exposed in a combustion chamber of a cylinder head, the spark plugs are arranged in a central portion (S) of the combustion chamber and radially surrounding the central portion. , a two-cycle engine characterized in that the ignition plug is ignited by combining the spark plug with one part of the suction hole part (A, B, D) excluding the central part (S) and the exhaust hole part (C). Multi-ignition device.