RU2239925C1 - Spark plug for internal-combustion engine - Google Patents

Abstract

FIELD: electrical equipment for internal-combustion engines of motor cars, aircraft, and the like.

SUBSTANCE: proposed spark plug characterized in more complete spark discharge energy transfer to working mixture thereby enhancing reliability of mixture ignition and completeness of its combustion has body that accommodates insulator, main pin-type electrode, and annular electrode. Main electrode is secured in insulator central bore so that its effective end protrudes from insulator butt-end. Annular electrode is made in the form of hollow cylinder with hole at bottom whose inner space around main electrode forms precombustion chamber. Annular electrode bottom hole communicates with combustion chamber; it is coaxial to main electrode and forms spark gap together with side surface of its end. Length of main electrode part protruding from insulator butt-end equals its two or three diameters with annual electrode accordingly elongated.

EFFECT: enhanced operating efficiency of spark plug.

1 cl, 1 dwg

Description

The invention is intended for use in internal combustion engines of cars, aircraft, etc. and relates to electrical equipment of internal combustion engines.

Known standard spark plugs containing a housing, an insulator, a central electrode and a curved side electrode, forming a spark gap with the end surface [S. Bannikov, Electrical equipment of cars. M .: Transport, 1977, p.223. Orlik A.S., Kruglov M.G. Internal combustion engines. M.: Mechanical Engineering, 1990, p. 161]. The design of the standard candle medium has not changed for more than 100 years.

The main disadvantages of the candles of this design are, firstly, that this design of the candle does not allow you to set fire to the gas mixture at the optimal distance from the wall of the combustion chamber. During the compression stroke, the movement of the working mixture is accompanied by velocity gradients, turbulent pulsations, which nonlinearly depend on the engine speed. Large speed gradients of the benzene-air mixture are observed near the cylinder walls in a layer of the order of 3 mm, and the absolute value of the gradient during combustion near the wall is comparable to the speed gradient during absorption [Semenov ES The study of turbulent gas motion in a piston engine. Sat Articles on combustion in a turbulent flow. Discussion at the All-Moscow seminar on combustion at the Energy Institute. USSR Academy of Sciences. M., Publishing House of the Academy of Sciences of the USSR, 1959, p.141]. This design introduces significant gas-dynamic disturbances in the region of the chamber wall, which negatively affects the efficiency of the process of ignition and combustion of the mixture. In addition, the insulator is not protected from combustion products and is in heavy thermal operation.

Secondly, the spark arising in the spark gap is closed from the main volume of the working mixture by the side electrode and, as a result, the ignition of the mixture is not effective enough.

Thirdly, the spark gap in this design of the plug is not rigidly fixed and it can vary arbitrarily during engine operation due to temperature stresses arising in the side curved electrode. Fourth, this candle design cannot ensure complete combustion of the mixture.

A spark plug is also known [RF patent No. 2059334. Priority 09/23/94, IPC H 01 T 13/20, publ. 04/27/96. Spark plug for internal combustion engine. Nekhoroshev L.A., Kalashnikov Yu.D.], containing an insulator in the housing and a central electrode having a rod part located in the hole of the insulator, and a disk part, above which a microfocus chamber is connected to the combustion chamber through an annular gap. The side electrode is made in the form of a casing having the form of a glass, the walls of the casing being solid and the bottom has a cylindrical hole in which the disk part of the central electrode is placed, the diameter of which is equal to the diameter of the insulator end face.

The disadvantages of a candle of this design include the fact that the presence of micro-cameras in it cannot essentially affect the ignition process, because ignition of a combustible mixture from a spark with equal probability spreads both in the combustion chamber of the engine cylinder and in the microframe. The design of the microformer itself has a drawback due to the presence of an insulator in it, which leads to temporary uncertainty of the combustion processes in the microformer.

In addition, this design of the electrodes does not allow to obtain a volume corona discharge in a candle, which then passes into a spark for high-voltage pulse parameters in serial ignition systems, and does not allow for an effective microframe chamber volume for a real candle design.

Known spark plug [application WO 9601512 A1, 95, publ. 01/18/96, IPC H 01 T 13/54], containing a ring electrode, a cylindrical insulator and a main electrode, which is fixed in the Central hole of the insulator. An opening is formed in the ring electrode, which is removed from the end of the main electrode and is communicated by a venturi channel connecting the preliminary combustion chamber to the combustion chamber of the engine cylinder. The spark gap between the end of the main electrode and the ring electrode is not constant due to the geometric configuration of the end of the main electrode. A spark is formed between the working end of the main electrode and the ring electrode.

The disadvantages of the candles of this design include the fact that the ignition conditions of the mixture in the preliminary combustion chamber can be unstable due to the fact that the design of the ring and end faces of the main electrodes do not allow a stable spark discharge, because ignition of the mixture from a spark can equally likely propagate either into the preliminary combustion chamber, or into the venturi channel, or simultaneously into the preliminary combustion chamber and the venturi channel, and this can lead to instability of the combustion process in the combustion chamber of the engine cylinder.

The prototype is a spark plug [RF patent No. 2181919], comprising a housing, an insulator fixed therein, a main rod electrode fixed in the central bore of the insulator so that the working end of the electrode protrudes from the end face of the insulator, a ring electrode with a central through cavity protruding beyond the end face the main electrode, a prechamber made in a ring electrode, surrounding the main electrode and communicating with the combustion chamber of the engine cylinder, while the prechamber consists of two prechambers: the main and the additional. The main prechamber actually represents an opening in the combustion chamber of the engine, into which the end of the main electrode partially enters (a spark gap is formed in this case), and an additional cylindrical recess coaxial with the main prechamber with a flat bottom. The prechambers communicate through the annular gap between the bottom of the recess and the end of the insulator.

The disadvantages of the candles of this design include the fact that due to the finite time of flame propagation in the prechamber, it is necessary to adjust the ignition timing, the magnitude of which affects the combustion process of the mixture and engine power. In addition, this design of the electrodes and the insulator does not allow the volume of the prechamber to be large to create an intense flame.

The technical problem to be solved consists in setting the mixture in the combustion chamber of the engine cylinder together with the help of an intense flame coming out of the spark plug, and with the help of an electric spark, which can increase the efficiency of the spark plug (the efficiency of the engine increases, the content of harmful substances decreases).

The specified technical problem is solved by a spark plug for an internal combustion engine, comprising a housing, an insulator fixed therein, a main rod electrode fixed in the central hole of the insulator so that the working end of the electrode protrudes from the end face of the insulator, the ring electrode in the form of a hollow cylinder forming its inner cavity around the main electrode a prechamber, with a hole in the bottom aligned with the main electrode and connected to the combustion chamber of the engine cylinder, forming together with The touch surface of the closure of the main electrode the spark gap, in which, according to the proposal, the length of the insulator protruding from the end portion of the electrode is made equal to two - three of its diameter with a corresponding lengthening of the annular electrode. The design of the main and ring electrodes of the candle provide a larger volume prechamber.

The inventive spark plug for an internal combustion engine is illustrated in the drawing.

The drawing shows a longitudinal section of a spark plug.

The spark plug for an internal combustion engine contains an insulator 1 fixed in the housing 2, an annular electrode 3, forming a prechamber 4 with its internal cavity, a spark gap 5 formed by the protruding part 6 of the main electrode 7 and the hole surface in the bottom of the annular electrode 3.

The candle works as follows. During the compression stroke, the working chamber 4 is filled under pressure with the working mixture. In the pre-chamber 4, the working mixture is injected through the annular spark gap 5 at a high speed and, as a result, an additional spraying of the mixture entering it occurs. At the stage of completion of the process of filling the prechamber 4 with the working mixture, a high voltage voltage pulse is applied to the main electrode, causing a corona discharge on its side surface, which then passes into the spark discharge in the annular gap 5, which reliably ignites the working mixture in this gap, which causes the initial mixture to ignite in prechamber 4 and in the combustion chamber. When the mixture is burned in the prechamber, the pressure in it is greater than in the combustion chamber, and therefore, a flame torch and combustion products will fly out of the prechamber into the combustion chamber, which together with the electric spark reliably ignite the main charge of the working mixture. When the length of the protruding part of the electrode 7 is less than two of its diameters, it leads to instability and uncertainty of the combustion processes in the prechamber, and when the length is greater than three diameters, an unreasonable increase in the dimensions of the candle occurs.

The proposed candle allows you to provide a more complete transfer of spark discharge energy to the working mixture, to increase the reliability of ignition of the mixture and the completeness of its combustion, almost regardless of engine speed.

The results of testing spark plugs of this design in engines VAZ 2106, ZAZ 406 confirmed its expected characteristics.

The specified implementation of the pre-chamber and electrodes allows you to upgrade existing, commercially available spark plugs for internal combustion engines with minimal cost.

Claims (1)

Spark plug for an internal combustion engine, comprising a housing, an insulator fixed therein, a core main electrode fixed in the central bore of the insulator so that the working end of the electrode protrudes from the end face of the insulator, an annular electrode in the form of a hollow cylinder, forming a prechamber with its internal cavity around the main electrode with a hole in the bottom, coaxial with the main electrode, of the communication with the combustion chamber of the engine cylinder, which together with the side surface of the end forms the main spark electrode gap, characterized in that the length of the protruding from the end of the insulator of the electrode part is made equal to two to three of its diameters with a corresponding extension of the annular electrode.