WO2008116711A1

WO2008116711A1 - Internal combustion engine comprising an engine brake

Info

Publication number: WO2008116711A1
Application number: PCT/EP2008/052169
Authority: WO
Inventors: Frank Bolte; Stefan Hubel
Original assignee: Schaeffler Kg
Priority date: 2007-03-24
Filing date: 2008-02-22
Publication date: 2008-10-02
Also published as: WO2008116711A9; DE102007014250A1

Abstract

The four-stroke internal combustion engine comprises a crankcase and at least one cylinder arranged therein, a working piston being guided in the cylinder by a crankshaft, at least one cylinder head closing the cylinder, the inlet and outlet ports of said cylinder head being governed by at least one inlet and outlet valve each that is biased by a closing spring. Said valves can be actuated by transmission elements driven by a camshaft. The engine further comprises a brake control device which is used to build up pressure in the outlet system, especially in the outlet ports, and/or to additionally open at least one outlet valve. A hydraulic valve play compensation element is mounted in at least one transmission element between the camshaft and at least one inlet and/or outlet valve and comprises a piston (3), a cylinder housing part (2) interacting with the piston (3), an interposed return spring (18) and a check valve (4). An actuated blocking device delimits the movement of the piston (3) relative to the cylinder housing part (2) and/or of the cylinder housing part (2) relative to the outer housing (1) connected to one of the transmission elements or a transmission element at least in one direction of movement.

Description

Name of the invention

Internal combustion engine with engine brake

description

Field of the invention

Internal combustion engine according to the four-stroke method with a crankcase and at least one cylinder arranged therein, in which a working piston is guided by a crankshaft, with at least one cylinder head closing the cylinder whose inlet and outlet channels of at least one inlet and outlet valve controls are, which are actuated by driven by a camshaft transmission elements, and with a brake control device, by means of which a pressure build-up in the exhaust system, in particular in the exhaust ports, and / or an additional opening of at least one exhaust valve.

Background of the invention

Such a generic engine is well known. Also known are several systems for engine brake control.

A system includes an exhaust throttle disposed in the exhaust system of the internal combustion engine. The engine must work against the increased pressure in the exhaust system and thus provides braking power. Another system, DE 39 04 497 C1, has a decompression device. In this system, the exhaust valve is opened before the end of the compression stroke and thus released the resulting pressure in the combustion chamber. As a result, the energy in the subsequent relaxation cycle is no longer returned to the engine and there is a braking effect.

It is also known to keep one of the exhaust valves open by a small amount during the braking operation, so that an ongoing decompression with corresponding braking effect occurs.

It has been found that hydraulic valve lash adjusters, also referred to as "HVA" in the present application, do not function satisfactorily in conjunction with brake devices because, for example, there is a risk that the HVA will not engage during braking operation - want to adjust.

Object of the invention

The object of the invention is therefore to modify a hydraulic valve clearance compensation element so that it is suitable for installation in the valve train of internal combustion engines with engine braking devices. In this case, the HVA should be designed so that it does not lead to readjustment in conjunction with a motor brake control. It should be able to guarantee a reliable operation under all conditions.

Summary of the invention

The object of the invention is achieved in that in at least one of the transmission elements between the camshaft and at least one inlet and / or outlet valve, a hydraulic valve clearance compensation element a is constructed, which has at least one piston, a cooperating with the piston cylinder housing part and a check valve and that an actuatable locking device is provided, the movement of the piston relative to the cylinder housing and / or the cylinder housing with respect to an outer housing connected to a transmission element in a Movement direction limited. This configuration ensures that the HVA function is maintained during engine braking operation, but the HVA can not adjust beyond the movement limitation. This prevents the pumping of the HVA, although the exhaust valve (s) are partially opened during engine braking operation and the transmission elements are at least partially relieved. During the arrest limit, the HVA may drop under load and displace within the limited range when relieved, with the HVA again compensating for the maximum possible descent when exiting the braking mode.

In a further embodiment of the invention, it is proposed that the actuatable locking device has a clamping sleeve which forms a stop by means of a surface and a mating surface on the cylinder housing part, on a component connected to the cylinder housing, on the outer housing or on a transmission element. This ensures that the cylinder housing with open outlet valve, so at least partially relieving the transmission elements, does not inflate further. The fact that the locking device can be locked at any point, the position of the stop is variable and adapts to the working position of the HVA ^* s. The HVA is therefore in the position in which it is at the beginning of the engine brake control, a stop assigned and thus limits the movement in one direction.

The clamping sleeve encloses the cylinder housing part, wherein the surface of the clamping sleeve part of a flange and the counter surface part of a

Paragraph on the cylinder housing part, on the outer housing or on a transmis- is transmission element or component of the cylinder housing part connected to the component.

The clamping sleeve is advantageously arranged between the cylinder housing part and the outer housing, wherein the clamping device of the locking device is in operative connection with the clamping sleeve and the outer housing or the cylinder housing part. As a result, the clamping sleeve can be fixed via the clamping device and the cylinder housing part can be delimited via the stop.

In a preferred embodiment of the invention, it is proposed that the clamping device is arranged in a cylindrical recess of the outer housing and has a clamping ring, which itself preferably has a conical surface on the inner or outer side. This preferably conical surface is directly or with the interposition of rolling elements with a conical or cylindrical wall surface of one of the adjacent parts in operative connection. In this case, the outer or inner surface of the clamping sleeve may be the conical wall surface.

The clamping ring is loaded in a direction of movement by the force of a return spring and loadable in the opposite direction by means of hydraulic fluid. Through the wall surfaces of the clamping sleeve and the outer housing and the clamping ring or a separate control piston, a pressure chamber is formed which has a control connection. The return spring in turn is supported on the clamping sleeve.

If no hydraulic pressure fluid is conducted to the clamping ring or the control piston, then the restoring spring presses the clamping ring out of the area of the conical wall surface, so that the clamping sleeve is freely movable and the HVA is free to adjust. Shortly before the braking operation is initiated, hydraulic pressure fluid is passed to the control port, so that it moves the clamping ring in the direction of the return spring and the return spring Clamping sleeve moves until the stop between the clamping sleeve and the cylinder housing part or the component connected to the cylinder housing, eg spring washer, comes into contact. Upon further movement of the clamping ring, this comes to the conical wall surface and clamped there the clamping sleeve with the outer housing or the cylinder housing part, so that no inflation of the HVA takes place during the engine braking operation. Due to the jamming of the clamping sleeve and the resulting locking in this position, no force is exerted on the HVA to the effect that it is further compressed and thereby falls unintentionally. Of course, careful matching of the conical wall surface and its location, as well as the force and length of the return spring and the pressure of the hydraulic fluid, to limit the expansion of the HVA without significantly compressing or sinking it.

Advantageously, a bead is incorporated on the wall surfaces of the clamping sleeve and / or the outer housing, which causes a limitation of the movement of the clamping ring relative to the force of the return spring. In another embodiment, a clamping ring is attached to the cylinder housing part for the same purpose. This ensures that the return spring does not expand so far when the pressure of the hydraulic fluid decreases that a limitation of the movement of the cylinder housing part and thus a limitation of the control movement of the HVA occurs. Furthermore, it is achieved that the clamping ring does not obscure the control connection and can therefore endanger the functional safety during braking operation.

The outer housing may be designed as a separate component and be installed at a suitable location of one of the transmission elements. But it can also be part of one of the transmission elements. Brief description of the drawings

For further explanation of the invention reference is made to the drawings, in which embodiments of the invention is shown in simplified form. Show it:

FIG. 1 shows a section through a hydraulic valve lash

Compensation element with locking device in a freely movable position,

2 shows a section through the HVA according to FIG. 1 in the locked position, FIG.

FIG. 3 shows a section through a hydraulic valve lash

Compensation element with locking device in a modified embodiment,

Figure 4: a section through a hydraulic valve clearance compensating element with locking device similar

3, in which an additional spring is installed,

FIG. 5: a section through a hydraulic valve lash

Compensation element with locking device similar to Figure 3, in which the locking device is modified and

FIG. 6 shows a section through a hydraulic valve lash

Compensating element with locking device, in which a component connected to the cylinder housing part serves as a stop. Detailed description of the drawings

In FIGS. 1 to 6, as far as shown in detail, 1 denotes an outer housing which is located in a rocker arm, in a towing / oscillating lever, a ram, a bridge between two valves or in another transmission element between the camshaft and the camshaft. and / or exhaust valve can be installed. However, the outer housing 1 can also be part of one of these components or formed in one piece with one of these components. The outer housing 1 has an inner opening in which a cylinder housing part 2 is installed, which is pot-closed. In the cylinder housing part 2, a piston 3 is guided, which forms an oil high pressure chamber with the cylinder housing part 2, to which a central bore in the piston is connected, which can be closed by means of a non-return valve designated 4. In the oil high-pressure space or an extension of the same designated a return spring 16 is mounted, which exerts on the piston 3 and the cylinder housing part 2 a compressive force. In a cylindrical recess of the outer housing 1, a clamping device 6 is installed with a clamping sleeve 5. The clamping device 6 has a return spring 7, which is supported on a surface of the clamping sleeve 5. In the embodiment of Figure 5, the return spring 7 is formed as a plate spring.

The restoring spring 7 is also operatively connected to a clamping ring 8 which forms with the walls of the clamping sleeve 5 and the outer housing 1 (FIGS. 1 and 2) a pressure chamber 9 which is provided with a control port 10 via the hydraulic pressure fluid into the pressure chamber can be directed. In the exemplary embodiments according to FIGS. 3 to 6, a control piston designated 17 is installed, which is approximately U-shaped in cross-section, is slidably guided on the walls of the cylinder housing part 2 and the outer housing part 1, forms the pressure space 9 with these and forms the Compressive force on the clamping ring 8 transmits. The outer surface of the clamping sleeve 5 has in the region of the return spring 7 has a conical surface, so that upon pressurization of the pressure chamber 9, which is greater than the force of the return spring, a clamping of the clamping ring 8 takes place on the clamping sleeve. This also applies to the embodiment according to FIG. 3 with the modification that the inner surface of the clamping sleeve 5 has the conical surface. In the embodiments according to Figures 4 and 5 5 rolling elements 19 are installed between the clamping ring 8 and the inner surface of the clamping sleeve, which cause a corresponding jamming of the clamping sleeve 5 with the outer surface of the cylinder housing part 2, wherein in Figure 6, the clamping ring 8 with the outer surface of Clamping sleeve 5 via rolling elements 19 in connection düng and the jamming takes place with the outer housing 1.

The clamping sleeve 5 extends according to Figures 1 and 2 between an inner bore of the outer housing 1 and the cylinder housing part 2 and has outside of the outer housing 1, a flange 11 which is associated with a shoulder 12 of the cylinder housing part 2. In the exemplary embodiment according to FIGS. 3 to 6, the clamping sleeve 5 has abutment surfaces which form a stop with a component fastened to the cylinder housing part 2, spring ring 18, or the outer housing 1. Namely, if the hydraulic valve clearance compensating element brought into its locking position, so moves after pressure buildup in the pressure chamber 9, both the clamping ring 8 and the clamping sleeve 5 via the return spring 7 to the flange 11 on the shoulder 12 of the cylinder housing part 2 or the surface of the clamping sleeve 5 at which is connected to the cylinder housing part 2 connected to the spring ring 18 or on the opposite surface of the outer housing 1. A squeezing or lowering of the HVA's does not take place, since this decrease counteract the check valve 4, the oil in the oil high pressure chamber and the return spring 16 in the high-pressure oil space. Thereafter, the clamping ring 8 continues to move until it reaches the conical outer or inner surface of the clamping sleeve 5 according to the principle of a freewheel in its clamping position and by slight expansion or compression of the clamping ring 8 is a locking of the clamping sleeve 5 on the outer housing 1 or the cylinder housing part 2 , The clamping ring 8 may also be slotted in the manner of a piston ring for ease of radial mobility. The respective cylinder housing part 2 or outer housing 1, which is not operatively connected to the lock, is unaffected by the clamping, so that the HVA can still freely adjust within the limit of the stop.

On the outer wall of the clamping sleeve 5, a bead is formed, which limits the movement of the clamping ring 8 due to the force of the return spring 7 and prevents obstruction of the control terminal 10. The outer housing 1 is provided with a support disk 14, on which the piston 3 can be supported. In the support disk 14 there is a connection opening 15, through which the HVA hydraulic fluid, in particular oil of the internal combustion engine, is supplied.

In the exemplary embodiments according to FIGS. 1, 2 and 6, the control of the clamping device 6 takes place via the control connection 10, to which hydraulic pressure fluid can be fed separately from the supply of hydraulic fluid to the HVA. It is a so-called two-flute design.

In the exemplary embodiments according to FIGS. 3 to 5, the control of the clamping device 6 takes place via the connection port for the hydraulic pressure fluid for the HVA, wherein a change in the pressure actuates the clamping device. In this so-called 1-flood design a careful coordination of the forces in the clamping device, the return spring, etc. is required. For this purpose, as shown in Figure 4, an additional spring 20 may be installed between the control piston 17 and the support plate 14. LIST OF REFERENCE NUMBERS

1 outer enclosure

2 cylinder housing part

3 pistons

4 check valve

5 clamping sleeve

6 clamping device

7 return spring

8 clamping ring

9 pressure chamber

10 control connection

11 flange

12 paragraph

13 bead

14 support disk

15 connection opening

16 return spring

17 control piston

18 spring washer

19 rolling elements

20 clamping ring

Claims

claims

1. Internal combustion engine according to the four-stroke method with a crankcase and at least one cylinder arranged therein, in which a working piston is guided by a crankshaft, with at least one cylinder head closing the cylinder whose inlet and outlet ports of at least one each with a closing spring loaded inlet and outlet valves are controlled, which are actuated by driven by a camshaft transmission elements, and with a brake control device by means of a pressure build-up in the exhaust system, in particular in the exhaust ducts, and / or additionally opening at least one exhaust valve, characterized that in at least one transmission element between the camshaft and at least one inlet and / or outlet valve, a hydraulic valve clearance compensation element is installed, the at least one piston (3) cooperating with the piston (3) cylinder housing part (2), an interposed Rückstel Lfeder (16) and a check valve (4), and in that an actuatable locking device is provided, the movement of the piston (3) relative to the cylinder housing part (2) and / or the cylinder housing part (2) relative to an outer housing connected to one of the transmission elements (1) or a transmission element is limited at least in one direction of movement.

2. Internal combustion engine according to claim 1, characterized in that the actuatable locking device has a stop which limits the readjustment movement of the HVA.

3. Internal combustion engine according to any one of claims 1 or 2, characterized in that the actuation of the locking device is effected by means of hydraulic pressure fluid.

4. Internal combustion engine according to one of claims 1 to 3, characterized in that the actuable locking device comprises a clamping sleeve (5) by means of a surface and a counter surface on the cylinder housing part (2), on a with the cylinder housing part (2) connected component, in particular Spring ring (18) on the outer housing (1) or on a transmission element forms a stop.

5. Internal combustion engine according to one of claims 1 to 4, characterized in that the clamping sleeve (5) surrounds the cylinder housing part (2) that the surface of the clamping sleeve (5) is part of a flange (11) and the counter surface part of a paragraph (12) on the cylinder housing part (2), on the outer housing (1) or on a transmission element or is part of the component associated with the cylinder housing part (2).

6. Internal combustion engine according to one of the preceding claims, characterized in that the clamping sleeve (5) between the cylinder housing part (2) and outer housing (1) is arranged and a clamping device (6) of the locking device with the clamping sleeve (5) and the outer housing (1). or the cylinder housing part (2) is in operative connection.

7. Internal combustion engine according to one of the preceding claims, characterized in that the clamping device (6) is arranged in a recess of the outer housing (1) and a clamping ring (8) which has a conical or cylindrical inner or outer surface, with a conical or cylindrical wall surface of a nes of the adjacent parts directly or with the interposition of rolling elements (19) is in operative connection.

8. Internal combustion engine according to one of the preceding claims, characterized in that the outer or inner surface of the clamping sleeve (5) forms a conical or cylindrical wall surface.

9. Internal combustion engine according to one of the preceding claims, character- ized in that the clamping ring (8) in a direction of movement by means of the force of a return spring (7) loaded and in the opposite direction by means of hydraulic fluid can be loaded.

10. Internal combustion engine according to one of the preceding claims, character- ized in that the return spring (7) on the clamping sleeve (5) is supported and that the clamping ring (8) with the wall surface of the clamping sleeve (5) and the outer housing (1) Pressure chamber (9) forms, on which a control connection (10) is provided for the hydraulic pressure fluid.

11. Internal combustion engine according to claim 10, characterized in that the clamping ring (8) by means of a piston (17) which is arranged in the cylindrical recess of the outer housing (1), of hydraulic pressure fluid is loadable.

12. Internal combustion engine according to one of the preceding claims, characterized in that on the wall surfaces of the clamping sleeve (5) and / or the outer housing (1) has a bead (13) for limiting the movement of the clamping ring (8) against the force of the return spring (7 ) is provided.

13. Internal combustion engine according to one of the preceding claims, characterized in that on the wall surface of the cylinder housing part (2) a clamping ring (20) is fixed, which limits the movement of the clamping ring (8) or the piston (17).

14. Internal combustion engine according to one of the preceding claims, characterized in that for actuating the clamping device (6) a control connection (10) is provided for hydraulic pressure fluid, which is independent of the inflow of hydraulic fluid to the HVA controllable (2-flow version).

15. Internal combustion engine according to one of the preceding claims, characterized in that the clamping device (6) can be controlled by changing the pressure at the inflow of hydraulic fluid to the HVA bar (1 -flutige design).

16. Internal combustion engine according to one of the preceding claims, characterized in that the outer housing (1) is part of one of the transmission elements.