AT10224U1 - INTERNAL COMBUSTION ENGINE, ESPECIALLY LARGE GAS ENGINE - Google Patents

Description

2 AT010 224U1

The invention relates to an internal combustion engine, in particular large gas engine, with at least one cylinder, wherein each cylinder has a main combustion chamber, and an unspurged antechamber connected to the main combustion chamber, in which an ignition device opens.

There are several types of ignition for fuel in the combustion chambers of internal combustion engines known.

WO 07/060046 A1 discloses an internal combustion engine with an open main combustion chamber, wherein a laser ignition device opens into the combustion chamber. The ignition of the gas mixture takes place directly in the main combustion chamber. This type of ignition is associated with considerable disadvantages for large gas engines, since only a very small portion of the combustion chamber is detected by the ignition and thus the combustion runs at a limited speed through the combustion chamber. However, an insufficiently fast combustion leads to disadvantages in the efficiency of the internal combustion engine.

Furthermore, it is known to ignite a combustible mixture in an unspung antechamber with spark ignition, for example by means of a so-called chamber candle. In this case, initiated by an electric spark ignition takes place in a small chamber whose volume is 0.1% to 0.5% of the compression end volume. The small chamber surrounds the spark plug. The prechamber is not supplied with additional gas, only the gas mixture flowing into the prechamber during the compression process is ignited therein. The advantage here is that in the main combustion chamber, in contrast to an open combustion chamber, more areas of the combustion chamber are detected by the ignition according to the outflowing flames torches. The disadvantage is that a significant electrode wear occurs on the spark plugs and that the position of the spark can usually only be realized at non-optimal locations in the prechamber.

In addition, it is known to use in large engines unspunged pre-chambers with Zündstrahlzündung. The ignition by an ignition jet takes place in an antechamber. The pre-chamber volume is usually 2% to 7% of the final compression volume. No additional gas is fed into the pre-chamber, only the mixture flowing into the chamber during the compression process is ignited therein. The advantages are that there is no spark plug wear and that the ignition source is very energetic. The disadvantage is the need for a second fuel for the ignition.

Furthermore, rinsed pre-chambers are known with Kerzenzündung. Ignition takes place through a spark or a spark plug in an antechamber. The pre-chamber volume is usually 1% to 3% of the final compression volume. In the pre-chamber additional gas is supplied, which is ignited together with the inflowing during the compression process in the pre-chamber mixture. The disadvantages are mainly the spark plug wear, but also the system complexity due to the additional gas supply. The advantage is the high-energy ignition source, despite the avoidance of a second fuel.

The object of the invention is to achieve in a large gas engine with an open main combustion chamber in the simplest possible way increased combustion stability and high efficiencies.

According to the invention this is achieved in that the ignition device is designed as a laser ignition device.

It is preferably provided that the prechamber has a volume which is less than 1% of the final compression volume. In this case, the prechamber may be formed by a chamber housing projecting into the main combustion chamber.

In the context of the invention it is further provided that the antechamber via at least one

Claims (4)

3 AT 010 224 U1 Overflow hole is connected to the main combustion chamber. In a small prechamber, whose volume is less than 1% of the final compression volume, the ignition is realized instead of an electric spark by a focused laser. The pre-chamber has no supply of additional gas. Via one or more overflow holes, the pre-chamber is flow-connected to the main combustion chamber. The ignition location by the laser (focus position, location of the breakdown) is chosen so that it is in a favorable range for the ignition (in terms of flow, air ratio and residual gas content). The shape of the inner shape of the antechamber is such that as little as possible mixing of the residual gas with the fresh mixture takes place and can thus be ensured that good ignition conditions prevail at the ignition. The advantage of the ignition by a laser ignition device in a prechamber is that no electrode wear occurs and that nevertheless a wide area of the main combustion chamber can be detected by the flame torches from the overflow holes and thus a fast combustion with high efficiency can be ensured. The invention will be explained in more detail below with reference to FIG. The figure shows an internal combustion engine according to the invention in a longitudinal section through a cylinder. In each cylinder 1 of a large gas engine, a reciprocating piston 2 is arranged in each case. Between the piston 2 and the cylinder head 3, a main combustion chamber 4, in which the overflow holes 5 of an antechamber 6 opens. The pre-chamber 6 is formed by a projecting into the main combustion chamber 4 chamber housing 9. In the positioned in the cylinder head 3 pre-chamber 6 via a combustion chamber window 7 an ignition laser device 8 to ignite a fuel-air mixture within the pre-chamber 6 a. After ignition in the pre-chamber 6, there is the outflow of flame torches through the overflow holes 5 in the main combustion chamber 4, whereby a large initial flame in the main combustion chamber 4 is formed and favors a rapid burning. By the laser ignition in the pre-chamber 6, a higher leaning of the fuel air mixture, as well as a high efficiency achieved and candle wear, and the onset of a Zündkraftstoffes be avoided. Claims 1. An internal combustion engine, in particular a large gas engine, with at least one cylinder (1), each cylinder (1) having a main combustion chamber (4) and an unspurged antechamber (6) connected to the main combustion chamber (4), in which an ignition device ( 8), characterized in that the ignition device (8) is designed as a laser ignition device (8). 2. Internal combustion engine according to claim 1, characterized in that the pre-chamber (6) has a volume which is smaller than 1% of the sealing end volume. 3. Internal combustion engine according to claim 1 or 2, characterized in that the pre-chamber (6) via at least one overflow bore (5) with the main combustion chamber (4) is connected. 4. Internal combustion engine according to one of claims 1 to 3, characterized in that the prechamber (6) is formed by a in the main combustion chamber (4) projecting chamber housing (9) 4 4AT 010 224 U1. For this purpose 1 sheet of drawings