Technical field

The present invention relates to a method and an arrangement for opening a valve that is arranged for communicating with a space with excess gas pressure phases, especially a cylinder space in an internal combustion engine.

Background of the invention

There are various ways to perform engine braking in conjunction with internal combustion engines. One way is to brake the exhaust gas discharge from the engine with the aid of a throttle that is located in the exhaust gas system of the engine. Another way is to utilize the exhaust gas valves/outlet valves by regulating their opening process in such a manner that a deviation from the normal opening process takes place. There is also a need for an auxiliary means for bringing about the initial opening of inlet valves and/or outlet valves at high cylinder

counterpressures.

Object of the invention

An object of the present invention is to bring about a method and an arrangement that make possible the opening of outlet valves and/or inlet valves even when the cylinder pressure is high. This creates possibilities for controlled engine regulation such as, for example, gas exchange, engine braking and gas injection to actual cylinders.

The invention is suited for engine types that comprise valves such as, for example, internal combustion engines, piston engines, compressors, etc. The invention makes possible a valve control that can be varied in a simple manner, that is very advantageous and that can be readily combined with a customary valve control that is used for normal engine operation. The invention can also serve as a servo arrangement for facilitating normal valve openings.

The object of the invention is achieved in that the method and the arrangement have the characteristic features indicated in the claims.

Advantages of the invention

Among the many advantages of the invention the following can be mentioned. The invention offers an attractive complement to valve-controlled internal combustion engines and can carry out a supplementary valve control in conjunction with, for example, engine braking. It can also bring about an initial opening during normal valve opening and thus guarantee an addition of force that makes possible a valve opening under high counterpressures.

The invention has both technical and economic advantages. Short description of the drawings

Exemplary embodiments of the invention will be described in the following with reference made to the attached drawings.

Figure 1 schematically shows an arrangement in accordance with the invention. Figure 2 shows the arrangement in accordance with the invention in a cross section.

Detailed description of the exemplary embodiment shown

Fig. 1 and 2 schematically show a space in the form of a cylinder 10 in an internal combustion engine and a valve 11 that is arranged at the cylinder and that can be an inlet valve or an exhaust gas valve. It shall of course be realized that the cylinder 10 is provided in reality with at least two valves. The valve 11 is acted on in such a manner as to open with the aid of a manoeuvring arrangement 12 in the form of, for example, a camshaft with associated push rod 13 and a rockable lever arm 14 in accordance with conventional principles or in accordance with other known solutions. A return spring 15 is arranged for the closing movement of valve 11. Valve 11 comprises a valve rod 16 and a pressure rod 17 arranged on it that is acted on during the opening movement by the manoeuvring arrangement 12 that thus guarantees the normal regulation of the opening and closing pattern of the valve. It can be seen that the manoeuvring arrangement 12 can be formed in several different ways.

According to the invention a slave piston 20 is arranged in an annular manner around the pressure rod 17. The slave piston 20 can slide axially along the pressure rod 17. The pressure rod 17 comprises a thickened part 21 against which the slave piston 20 acts. The return movement of the slave piston 20 is ensured by a return spring 22.

A conduit 30 is arranged from the combustion space/cylinder 10 and runs to a first valve/control valve 31 which is constituted in the example shown by a so-called ball valve with a spring-influenced ball 32 that in the normal state seals against an annular sealing surface 33. A conduit 35 runs from the valve 31 to a second valve/control valve 40, as is apparent from the figures. A conduit 45 runs from the valve 40 to a cylinder 50 for a primary piston 61 at a pressure amplifier 60. A conduit 70 runs from a cylinder 51 for a secondary piston 62 at the pressure amplifier 60 to a cylinder 25 for the slave piston 20. The diameter of the primary piston 61 is greater than the diameter of the secondary piston 62 so that an amplification of pressure is obtained.

In order to ensure the return movement of the pressure amplifier 60 a return spring 63 is arranged, as is apparent from the figures.

A control member 80 is arranged for the control of the valves 31 and 40 so that the desired opening cycles in accordance with the invention are obtained at the valve . If an opening of the valve 11 is desired, the control member 80 initiates an opening of the valves 31 and 40 so that pressurized gas from the cylinder 10 can pass via the conduits 30,35 and 45 to the primary piston 61 of the pressure amplifier 60 and put it in motion, during which an increase in pressure takes place in a fluid/liquid, for example, hydraulic oil or another liquid that is preferably

incompressible, enclosed in the conduit 70 and, for the rest, between the secondary piston 62 of the pressure amplifier 60 and between the slave piston 20. This brings it about that the slave piston 20 imparts to the pressure rod 17 and the valve rod 16 via the thickened area 21 a movement that opens the valve 11 , which movement is longitudinally limited by a holding-up tool (not shown) or by the working length of the slave piston 20. When the desired opening duration has been achieved the control member 80 is remanoeuvred in such a manner that the valve 31 closes the gas flow from the cylinder 10 and the valve 40 assumes a position for the discharge of return gas via a line/conduit 90. At this time the pressure amplifier 60 exerts a return movement on account of the removal of pressure and the action of the return spring. Even the slave piston 20 and therewith the pressure rod 17 and the valve 11 exert a return movement on account of the removal of pressure and the action of the return spring so that the valve 11 remains closed. It can be seen that the just-cited opening and closing of the valve 11 is entirely independent of normal valve openings and closings and that it also does not disturb a normal process of valve opening. Fig. 2 shows a control member 80 in more detail where a regulating rod 95 can be seen that acts on a valve ball 32 in such a manner that a valve opening is obtained at the same time as the regulating rod serves as a second control valve. It can be seen that the control valve arrangement or the control members can be formed in many different ways within the framework for the concept of the present invention. The first and the second control valves can be integrated, for example, in a single control valve or a control member that has the required control functions. Of course, even the control member 80 can have a varying formation within the framework of the present inventive concept and be integrated, for example, with remaining control members to a control member group.

It can be seen that the valve 31 can be replaced, for example, by a plate valve arranged at conduit 30 with an associated manoeuvring member, alternatively by a slide valve with associated manoeuvring member. Thus, it can be seen that there are many possibilities of variations as concerns the equipping of control members in the form of, for example, valves or manoeuvring members in the gas communication that is arranged between the space 10 and the pressure amplifier 60.

Fig. 1 also showed a number of locations A for venting and a filling location B for the fluid/liquid that can be, for example, hydraulic oil with a suitable quality.

The arrangement in accordance with the invention therefore has several areas of application. One area is, for example, engine braking. Another area is as an assisting valve opener for making possible pressure equalization and therewith for reducing the energy requirement during normal valve opening.

The arrangement can of course be complimented by required position sensors.

It is also possible to use an externally arranged source of compressed gas.

The invention offers a system for engine braking and a servo arrangement for valve opening. It can be seen that the invention can be used with all types of engines and other arrangements where the above requirements are present.

The invention is not limited to that which was shown and described but rather amendments and modifications are naturally possible within the framework for the attached claims.