DE2334504A1 - FREE PISTON MACHINE - Google Patents

Description

PATENT Attorney DIPL-INQ. JOACHIM «» ROAD

MC HANAU R0MEKSTR. H POSTBOX TW TEUl (HOI TELEQRAMME: HANAUPATENT TELEX:

Auguste MOIROUX ₁ Ecully, France July 5, 1973 Francois BERNARD, Lyon, France Str / Sk - 10 981

Free piston machine

The invention relates to measures for stabilizing and securing the operation of a directly coupled power and Working machine with free piston. Here the power part is an air-cooled diesel engine and the one driven in this way The monoblock piston also acts as a compressor in the working part.

Such crankless reciprocating compressors and similar free piston machines are known, for example, as free piston generators, and attempts have been made to do so To protect machines against internal piston stops.

In water-cooled machines, a slight excess of engine air Λ can be tolerated and is sufficient for this purpose,

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QfWGlNAL INSPECTED

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an ignition or expansion of the ignited fuel in the Motor beyond a limited position, which is determined by the two dead points of the freely movable set, does not occur. This happens because a safety limit at the dead center of the buffer piston of the freely movable Set is set, which also has at least a motor piston and a compressor piston.

According to a further feature of the invention, the floating set consists of a plurality of coaxial pistons which together are completely free and can even rotate around their axis and which have a motor part, an air buffer and an off limit two chambers with alternately larger and smaller volumes formed compression group. The diameter the pistons that make up the set can be different.

The individual relationships of the variables to one another, as found to be advantageous according to the invention, result from the attached subclaims.

Further details, features and advantages emerge from the following description of the drawing.

Show it:

Fig. 1 is a longitudinal section of a machine with a variable working direction, the freely movable Set from one block simultaneously performs the functions of the engine and compressor and

2 shows a graphical representation of the development of the dead centers of the freely movable set on the motor side and on the buffer side, this development being recorded as a function of the engine load is.

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because the corresponding elevated temperatures over the cooling to be mastered. As the amount of fuel injected increases, the engine work is increased. As a general The guideline based on experience is that with a λ combustion limit equal to 1.5 »the moving rate is in the vicinity of the fixed part arrives.

In air-cooled machines, which, however, according to a premixed and ignition-controlled cycle work, the energy is limited by the productivity, and the problem of overburning does not arise.

In the case of an air-cooled machine with variable working direction that works on a diesel cycle it is necessary to use an increased excess of air λ for cooling. provide. This increases the risk of over-injection strongly., At ^ = 3, the energy delivered by the motor can be in In relation to a λ limit = 1.5. It is then it is no longer possible to achieve a sufficient course through the construction, which is the case with such Excess energy represents sufficient protection against piston stops. Another remedy must be found will.

It is the object of the present invention to solve this problem by providing a security measure for one with a air-cooled diesel engine connected machine is made available and the at least one Preikolben with variable Has working direction.

A variable direction free piston diesel engine constructed in accordance with the invention and air cooled is, is characterized in that the protection against stops for the movable set is obtained in that

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In Fig. 1, a freely movable set from a block is shown, which follows an alternating reciprocating stretched motion. This unitary sentence or block consists of at least one engine piston 1, which is located in an engine cylinder with a diameter of 0.. shifts, a buffer flask 3, which is located in the buffer cylinder 7 with the diameter 0 moves and a compression piston 2, the diameter of which is 0_ larger than that of the other two pistons »The one in the middle Piston 2, which is part of the machine, moves in the compressor cylinder and delimits two chambers there. A compression chamber as the working part of the machine 5 on the buffer side and a chamber 6 for access and flushing Air for the engine part. The volume of these two chambers increases and alternately decreases in direction the displacement of the set whose maximum stroke C is less than an axial length 8 of the compression cylinder. The diameter 0W, 0, 0p are calculated so that the expansion of the ignited gases in the engine part stops before the floating sentence hits the (right) end of a cylinder.

In Fig. 2, the course of the movement of the ends of the engine piston 1 and the buffer piston 3 is the course of work Machine shown (curves 11 and 12).

The machine works as follows:

When the piston set is displaced according to arrow 9, the air in the engine cylinder 4 is compressed. At a certain pressure, the injected fuel ignites. The piston set changes direction and moves according to the arrow under the pressure of the burnt gases. The dead center of the piston 1 remains on this side of the end of the engine cylinder k (FIG. 1) and the machine always maintains a safety distance S "from stops on the cylinder head of the engine (FIG. 2).

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If, on the other hand, the piston set moves in the direction of arrow 10, there is a risk that it will hit the face of the Buffer cylinder 7 impacts and this risk increases with the energy supplied by the motor. The value of this energy is a function that increases with the volume of fuel burned and thus injected, in the case of an air-cooled one A substantial excess of air must be provided in the diesel engine> because this air is used for cooling. This excess air ensures good combustion even if there is an excessive injection of fuel, which will be dangerous by the fact It is possible that the combustion is triggered by the spontaneous ignition of the diesel oil in the air, which is caused by its compression has been brought to high temperature in engine cylinders.

In order to prevent stops on the end face of the buffer cylinder or the compression cylinder in such a machine, the present invention aims to limit the compression temperature in the combustion chamber H of the engine. For this reason, the fuel does not ignite before the dead center on the buffer side has a tendency to go beyond position D (FIG. 2), the safety limit position. Thus, the invention enables the engine to be automatically stopped in the absence of ignition, when the dead center on the buffer side approaches the cylinder base at a distance which is below the safety limit S ". This condition is achieved by precisely metering the motor energy, that is, by calculating and carefully studying the essential parameters in the construction of the machine, namely: fi>", 0, Q _n and C and these parameters are determined by

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the coefficients marked that they all add to the diameter 0L · of the motor in relation.

Expectations :

309884/05

Claims (1)

- 6 claims 1. Diesel free piston air-cooled machine with variable speed Direction of work, characterized in that the protection of the freely movable Piston set (1, 2, 3) against stops due to the failure of the ignition of the fuel in the engine above a limited position determined by any one of the dead centers of the floating piston assembly will.· 2. Free piston machine gerr.iiß claim 1, characterized by the fact that / ⁵ the safety limit position is set at dead center of the buffer piston (3) of the freely movable piston set. 3. Free piston machine like claims 1 and 2, characterized in that the freely moving piston set (1, 2, 3) consists of a cylinder with different diameters, which is coaxial are and delimit: - on one side a power or motor part (1, ^) - in the middle a compression group divided into two chambers (5,6) with alternately larger and smaller volumes, each of the volumes by the position of the compression piston (2) its diameter (0C) over the diameters (0 m, 0 M) of the Outer zones of the freely movable piston set is determined, - on the side opposite the motor side along the axis, an air buffer (7). 309884/0587 Free piston machine according to claims 1 to 3 , characterized in that the diameter 0 _{y of} the cylinder ( ¹ J) and the piston (1) in the motor part, the diameter 0 _{C of} the cylinder (5, 6) and the piston (2) in the compressor part , the diameter 0 of the cylinder (7) and the piston (3) in the m Buffer part, the maximum stroke C of the piston set is determined in such a way that the relationships 0 C Z m C
0- ~ M ' WT-. »0 M have a value included in a predetermined tolerance interval. Free piston machine according to Claim ¹ J, characterized in that the relationship between the compressor piston diameter (0 C) and the engine piston diameter (0 M) conforms to the law 1.6 <τ! _ £ < 1.9 0 H
follows. 6. Free piston machine according to claim 4, characterized in that the relationship between Buffer piston diameter (0 m) and engine piston diameter (0 H) the law 0.8 < ^{0 m} <^ 1.2 0 M. follows. 7. Free piston machine according to claim ¹ J, characterized in that the relationship between the maximum stroke (C) of the freely movable piston set and the diameter (0 H) of the engine piston is the law 0 M.
follows. 309884/0587 Blank page