WO2019122058A1

WO2019122058A1 - Piston cooling nozzle

Info

Publication number: WO2019122058A1
Application number: PCT/EP2018/086065
Authority: WO
Inventors: Jochen Holtel
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2017-12-20
Filing date: 2018-12-20
Publication date: 2019-06-27
Also published as: DE102017223465A1; EP3728809B1; EP3728809A1

Abstract

The invention relates to a piston cooling nozzle (1) comprising a cylindrical housing (2), a piston (3), and a spring (10). The piston (3) is arranged in the cylindrical housing (2) in a movable manner against the pressure of a pressurized oil, and the piston (3) is biased against a valve seat (5) by means of the spring (10). The valve seat (5) interacts with a piston head (6), and a cavity is formed downstream of the valve seat (5), wherein a transverse line (7) extends at least partly in the piston (3) starting from the cavity (4), and the transverse line (7) opens into a longitudinal line (8). The piston cooling nozzle (1) is improved in that the piston (3) has a shaft (14), and the longitudinal line (8) extends within the shaft (14), said shaft (14) being surrounded by the spring (10) and passing through an opening (13) in a base part (12).

Description

description

piston cooling

The invention relates to a piston cooling nozzle with the features of the preamble of

Patent claim 1.

Piston cooling nozzles are supplied with oil via a supply channel. The piston cooling nozzle has a valve which is set so that an injection at idle at low speed, with a small flow rate of the oil pump is not active. The piston cooling nozzle has a spring-biased piston, which is acted upon by a pressure oil counter to the spring force. If the oil pressure exceeds an opening pressure, the pressure oil flows through the piston cooling nozzle and is injected to the engine pistons.

In the prior art, the use of piston cooling nozzles with a ball valve is known.

These have the disadvantage that with increasing opening pressure of the volume flow can decrease. Ball valves may have the disadvantage that they tend to vibration excitation.

From DE 10 201 1 007 605 A1 an oil supply system for a reciprocating internal combustion engine is known. The supply of oil to a plurality of piston cooling nozzles is controlled by pressure operated valves which are designed so that the valves at a

open predefined opening pressure. The oil pressure delivered by a pump is controlled so that either during operation of the engine that does not require piston cooling, the oil pressure remains below that predetermined opening pressure or above the predefined opening pressure when piston cooling is required. The respective pressure-operated valve has a housing defining a cylinder chamber in which a piston is slidably disposed. A spring acts on one end of the piston to bias the piston to a valve closed position, the piston blocking an outlet thereby preventing oil from one inlet from passing the pressure operated valve to an outlet and then not to one or more shown piston cooling nozzles is passed on. When the pressure in the inlet exceeds a predetermined valve opening pressure, the pressure of the oil acting on the piston is sufficient to displace the piston against the action of the spring, thereby opening the oil flow from the inlet to the outlet and the oil flow to one or more piston cooling nozzles. The housing has a side outlet and a side inlet. In the closed position, the lateral surface of the piston blocks the outlet. In the open position, the piston is so far shifted so that the piston releases the outlet, connecting the inlet and outlet. In another embodiment of the pressure operated valve, the pressure operated valve includes a valve member in the form of a ball which is slidably supported. A spring acts on the ball such that it is biased to a closed position, the ball blocking an inlet thereby preventing oil from passing the valve to an outlet and then continuing to the piston cooling nozzles. In this case, the cylinder chamber has a longitudinally extending in the middle inlet, which opens into a cylinder chamber funnel-shaped. These

funnel-shaped mouth forms a valve seat, wherein the ball by a spring in the

Closed position against the valve seat or against the funnel-shaped mouth is pressed. Furthermore, the cylinder chamber at the opposite end face in the middle of an outlet.

From DE 602 14626 T2 a piston cooling nozzle is known. The piston cooling nozzle makes it possible to inject an oil against the bottom of a piston or against a tunnel of the piston. The piston cooling nozzle contains a valve, which opens only from a certain opening pressure. Instead of a ball valve in this case a piston valve is used to avoid the disadvantages of ball valves. Disadvantages of ball valves should be an oscillation and a vibration. A nozzle body has an axial through hole into which a tubular sleeve with axial bore without play engages. A piston has a closure head, which in

Upstream of the flow of oil is aligned to selectively against a

abut annular closure, which is integrally formed with the nozzle body and having a seat bore, which is traversed by the oil. Further, a helical compression spring is axially supported between a bottom integrally formed with the nozzle body and a downstream surface of the piston to urge the piston in the upstream direction against the annular closure seat. The piston is at his

Displacement along the longitudinal axis led, reducing the risk of oscillation and the

Instability avoids, so that the nozzle has a greater durability and a lower

Wear as a ball valve. The piston is guided the tubular sleeve. The tubular sleeve has a radially directed hole located immediately downstream of the annular closure seat for directing the fluid radially to one or more circumferential passages existing between the outer surface of the tubular sleeve and the axial through bore surface of the nozzle body. are. The circumferential passages are adapted to axially direct the oil to a radial fluid passage. The oil is thus derived radially. In a further embodiment between a downstream portion with lateral cylindrical guide surface and the closure head an annular outer recess is provided which forms an annular seat with the wall of the guide bore, which via radial bores of the piston with an axial bore of the piston communicates downstream to the axial

Through hole of the body is open, which conducts the oil to a radial fluid passage in the nozzle body. The oil enters a chamber of the body, in which the spring is arranged. The oil flows around the spring and enters through a passage passage through the soil in a further chamber from which radially now the oil is forwarded.

The invention is based on the object to improve this generic type piston cooling nozzle.

This object of the invention is now achieved by Kolbenkühldüse with the features of claim 1.

The piston is slidably disposed in the cylinder housing against the pressure of a pressure oil, wherein the piston is biased by the spring against a valve seat. The piston has a piston head, wherein the piston head cooperates with a valve seat. The piston has an Ouerleitung, wherein the Ouerleitung is in communication with a longitudinally extending longitudinal line. The longitudinal direction corresponds to the

Displacement direction of the piston. Ouerrichtungen are arranged transversely to the longitudinal direction. In particular, the output line may be perpendicular, i. extend radially in the piston. The longitudinally extending longitudinal conduit is formed in a shaft of the piston. The Ouerleitung is in particular formed downstream of a valve surface of the piston head, wherein the valve surface on the piston head cooperates with the valve seat. The piston head delimits with the cylinder housing an annular space, wherein the Ouerleitung extends in particular in the radial direction of the annular space up to the central longitudinal line in the shaft.

The shaft extends through an opening in a bottom part of the cylinder housing. An ejection opening at the shaft end protrudes in the assembled state of the

Piston cooling nozzle in the interior of the crankcase and is preferably oriented in the direction of the engine pistons. Now, if the pressure oil shifts the piston in the longitudinal direction, so also the shaft is moved in the longitudinal direction of the engine pistons. Due to the fact that the longitudinal channel is correspondingly long, namely projecting through a bottom part, a laminar flow is created which improves the spray pattern. As a result, the spray pattern is more concentrated, as a result of which the jet can strike the piston crown in a substantially point-like manner. There are no further lines for forwarding the Durcköls necessary, characterized in that the piston cooling nozzle is aligned with the shaft in the direction of the engine piston. As a result, the structure is simplified. The piston cooling nozzle is arranged in the mounted state in a receptacle of a crankcase. The piston cooling nozzle is inserted in the manner of a cartridge in a cylindrical receptacle. The assembly is simplified.

The selected type of piston cooling nozzle vibration excitations are avoided. The parameters opening pressure and flow velocity can be varied without the volume flow being reduced. Flow losses are reduced. The parameter

Opening pressure can be varied by selecting the characteristic of the spring. The

Flow rate can be selected by choosing the Ouerschnitts the outlet opening.

Vibration excitations are avoided in particular by the fact that the piston has a shoulder, wherein the piston is guided by means of the shoulder within the cylinder housing. The shoulder outer surface is cylindrical. The piston head has a smaller one

Diameter than the shoulder up. The piston head has a larger diameter than the shaft.

An advantageous flow characteristic is realized in that the piston head is dome-shaped and the valve seat is formed by a circular opening. As a result, the piston head can be well flowed around by the oil.

The Ouerleitung extends in the piston head, which has the advantage that here the wall thickness is large and so the stability of the piston is not affected.

The pressure oil is further accelerated at the exit from the piston cooling nozzle in that the longitudinal line is tapered towards an ejection opening. Alternatively, the

Longitudinal line have a constant Ouerschnitt, the Ouerschnitt is selected in view of the desired flow rate.

The shaft is surrounded by a spring. The spring is securely supported against tilting in that the spring is supported on a stop in an annular cavity in the region of the shoulder. The shoulder has a wall portion which radially surrounds the end of the spring. As a result, the end of the spring is kept centered. Furthermore, the piston cooling nozzle on a bottom part, wherein the spring is supported in particular on the ground part and on the other to a stop surface in the region of the shoulder. The bottom part may comprise a spring radially centered holding Wandabschitt. It is possible to perform the centering of the spring by the shaft alone. The bottom part may have a cylindrical wall portion which radially keeps the spring centered and surrounds the spring on the outside. A simple production of the piston cooling nozzle is achieved, inter alia, that the bottom part is held by a flanging of an edge of the cylinder housing.

There are now a variety of ways to design the piston cooling nozzle described above in an advantageous manner and further. For this purpose, reference may first be made to the claims subordinate to claim 1. In the following, a preferred embodiment of the invention will be explained in more detail with reference to the drawing and the associated description. In the drawing shows:

Figure 1 is a schematic longitudinal sectional view of a piston cooling nozzle with a valve assembly, wherein the valve assembly is shown in a closed position, and

Fig. 2 is a schematic longitudinal sectional view of the piston cooling nozzle of Fig. 1, wherein the valve assembly is arranged in an open position.

In Fig. 1, a piston cooling nozzle 1 is shown. The piston cooling nozzle 1 has a cylindrical cylinder housing 2. In the cylinder housing 2 is a piston 3 in the longitudinal direction

slidably arranged. The piston cooling nozzle 1 and in particular the piston 3 are acted upon by a pressure oil, which is indicated here by the arrows (not designated).

The cylinder housing 2 now has at one end face a bottom with a valve seat 5, wherein the valve seat opens into a cavity 4, provided that the piston 3 is in the open position (see Fig. 2). The valve seat 5 cooperates with a piston head 6. The piston head 6 is in particular dome-shaped or dome-shaped. The valve seat 5 is formed as a central opening, in particular as a bore, in the bottom of the cylinder housing 2.

The valve head 6 passes from the dome-shaped region in a particular cylindrical region, wherein between this cylindrical portion and the inner wall of the cylinder housing an annular space remains. When the pressure oil enters the cavity 4 through the valve seat 5, it also passes into this annulus. In the axial direction of this annulus is limited by a shoulder 9. The shoulder 9 also has a cylindrical peripheral surface, wherein the piston 3 by means of this cylindrical peripheral surface on the Inner wall of the cylinder housing 2 is guided. The diameter of the shoulder 9 is greater than the diameter of the upstream piston head 6.

The piston 3 now has a transverse line 7 extending from the annular space through the cylindrical peripheral surface of the piston head 6 into a longitudinal direction

extending longitudinal line 8 extends. In particular, two are radially extending

Transverse lines 8 present, which are formed during manufacture through a bore.

The central longitudinal line 8 extends within a shaft 14 of the piston 3. This shaft 14 has a smaller diameter than the piston head 6 and also as the

Diameter of the shoulder 9 up. The shaft 14 is surrounded by a spring 10, in particular a coil spring 10, which is supported on the one hand on a spring stop surface 11 in an annular receptacle in the region of the shoulder 9 and on the other hand on a bottom part 12, which closes the cylinder housing 2. Both the bottom part 12 and the shoulder 9 in this case have cylindrical wall sections which keep the ends of the spring centered or

embrace.

The longitudinal channel 8 tapers toward a tip or ejection opening 15 of the shaft 14, so that here the flow velocity of the pressure oil increases and the pressure oil can be ejected at a higher speed. The shaft 14 passes through an opening 13 in the bottom part 12. Between the shaft 14 and the opening 13 remains a small gap through which oil that enters the space of the spring 10 can also escape into the crankcase.

With the piston cooling nozzle 1 shown here, the parameters opening pressure and

Flow rate can be varied without reducing the flow rate.

Flow losses that occur, for example, in a ball valve are avoided.

LIST OF REFERENCE NUMBERS

piston cooling

cylinder housing

piston

cavity

valve seat

piston head

cross line

longitudinal line

shoulder

feather

Stop for the spring in an annular cavity in the region of the shoulder bottom part

Opening in the bottom part

shaft

ejection

Claims

claims

A piston cooling nozzle (1) having a cylinder housing (2), a piston (3) and a spring (10), wherein the piston (3) is slidably disposed in the cylinder housing (2) against the pressure of a pressurized oil, wherein Piston (3) by means of the spring (10) is biased against a valve seat (5), wherein the valve seat (5) cooperates with a piston head (6), wherein downstream of the valve seat (5), a cavity is formed, starting from the cavity (4) a transverse line (7) extends at least partially in the piston (3), the transverse line (7) opening into a longitudinal line (8), characterized in that the piston (3) has a shaft (14), wherein the Longitudinal line (8) extends within the shaft (14), wherein the shaft (14) of the spring (10) is embraced, wherein the shaft (14) passes through an opening (13) in a bottom part (12).

2. piston cooling nozzle according to claim 1, characterized in that the piston (3) has a shoulder (9), wherein the piston (3) by means of the shoulder (9) within the

Cylinder housing (2) is guided.

3. piston cooling nozzle according to one of the preceding claims, characterized in that the piston head (6) is dome-shaped and the valve seat (5) is formed by a circular opening.

4. piston cooling nozzle according to one of the preceding claims, characterized in that the transverse line (7) extends in the piston head (6).

5. Piston cooling nozzle according to one of the preceding claims, characterized in that the longitudinal line (8) is tapered to an ejection opening (15) towards.

6. piston cooling nozzle according to one of the preceding claims, characterized in that the spring (10) on a stop (1 1) is supported in an annular cavity in the region of the shoulder (9).

7. piston cooling nozzle according to any one of the preceding claims, characterized in that the spring (10) on the bottom part (12) is supported.

8. piston cooling nozzle according to one of the preceding claims, characterized in that the bottom part (12) has a spring radially centered holding Wandabschitt.

9. piston cooling nozzle according to any one of the preceding claims, characterized in that the bottom part (12) is held by a flanging of an edge of the cylinder housing (2).

10. Internal combustion engine with at least one engine piston and with a piston cooling nozzle (1) according to one of the preceding claims, characterized in that the

Piston cooling nozzle (1) with the shaft (14) is aligned in the direction of the engine piston.

11. Internal combustion engine according to the preceding claim, characterized in that the piston cooling nozzle (1) is arranged in a receptacle of a crankcase.