KR20120016068A - A control arrangement for an inlet valve in a piston engine - Google Patents

Abstract

The invention relates to a piston engine suitable between the cam device 5 of the cam shaft 4 of the engine 1 and the inlet valve mechanism 6 configured to open and close the inlet valve 3 associated with the cylinder of the engine. A control component for an inlet valve of a control body (7), wherein the control component (7) comprises a body part configured to be movable such that the piston device (9) is in force transmission connection with the cam shaft (4) and the valve mechanism (6). (8), wherein the body portion (8) and the piston device (9) comprise a first chamber (13) through which hydraulic medium can be selectively conveyed, and duct means (18, 18 ', 18 "). Together defining a second chamber 19 connected to the first chamber, the flow of hydraulic medium from the first chamber 13 to the second chamber 19 to provide a delay in closing of the inlet valve 3. The main body portion 8 from the first chamber 13 to the second chamber 19. Different two or more flow ducts (18a, 18b, 18c; 18'a, 18'b; 18 "a, 18" b, 18 "c) to form a route for the flow of the hydraulic medium is provided. Control means 17, 17 ', 17 "are provided for selecting the route of flow used in each case to provide different closing delays.

Description

CONTROL ARRANGEMENT FOR AN INLET VALVE IN A PISTON ENGINE

The present invention relates to a control arrangement for an inlet valve of a piston engine according to the preamble of claim 1.

In the operation of a four-stroke internal combustion engine there are situations where the cylinder is not provided with sufficient air for self-ignition to occur during the compression stroke. This is especially true for engines that are accounted for by high pressure, such as two-stage turbocharger engines during engine start and load variations. In this type of engine, higher pressures in combination with sharper or shorter cam nose forms are used to result in charging action which takes place in a shorter time respectively. Therefore, the opening time of the inlet valve under normal load of the engine is not long enough for this particular situation.

On the other hand, in order to minimize the discharge from the diesel engine, the timing of the inlet valve must be closed early before the bottom dead center of the piston, and the boost pressure must therefore be raised to obtain a sufficient amount of air in the cylinder. However, this kind of component suffers from a low engine load when the turbocharger's boost pressure is still relatively low.

One solution is to enhance the supply of inlet air during the open state of the inlet valve under this particular situation. Another solution is to provide a delay upon closing of the inlet valve to extend the opening time of the inlet valve when necessary. One solution for such a variable inlet valve closing (VIC) is described in patent document WO 2008/000899 which provides a specific delay for the closing of the inlet valve.

It is an object of the present invention to provide a further improved control arrangement for delaying the closing of the inlet valve of a piston engine. A particular purpose is to enable the selection of different delay times according to different situations, especially when the combustion engine is operated under low engine loads and during start-up of the engine.

The object of the invention can be fulfilled substantially as described in claim 1 and in other claims which show further details of different embodiments of the invention. According to the invention the body part is provided with two or more flow ducts for constructing different routes for the flow of hydraulic medium from the first chamber to the second chamber. In addition, control means are provided for selecting the route of flow used in each case to provide different closing delays. The route here may comprise one or more flow ducts depending on the application in each case. This makes it possible to obtain a solution that is practically easy to apply, reliable and can be used as needed.

The two or more flow ducts are advantageously configured to open in a common chamber or similar connecting duct configured in communication with the first chamber. The control means are then configured to operate in the common chamber or similar connecting duct.

Indeed it is advantageous for the second chamber to be provided in a guide member constructed between the cam device and a piston device movably corresponding to the movement of the cam device. The two or more flow ducts are thereby configured to open into the second chamber at different positions depending on the trajectory of the movement of the guide member. This provides a reliable configuration. Furthermore, the guide member is configured to act directly on the piston device only in the direction for opening the inlet valve when the delay function is used.

According to one embodiment the flow of hydraulic medium is configured through one of the flow ducts at one time and the control means comprises a control valve having a movable valve member provided with release means configured at one of the flow ducts. . The release means may be a narrowing portion having a dimension such that the flow flows through only one duct at a time.

According to another embodiment the control component comprises a separate control valve for each flow duct to provide a shorter delay time.

The control means are advantageously configured to be operated pneumatically by making use of a control system included in the engine. In particular charge air from the turbocharger of the piston engine can be used to control the control means. The operating pressure is advantageously configured to occur against the force of the spring, which provides an uncomplicated configuration and control.

The invention will now be described by way of example only, with reference to the accompanying schematic drawings.

1 is a diagram showing a skeleton diagram of a piston engine and its valve mechanism.
2-4 show an overall view of a control arrangement according to the invention in separate successive stages of operation.
5 is an enlarged view of a first embodiment of a control means according to the present invention.
6a and 6b show an enlarged view of a second embodiment of a control means according to the invention in two operating positions.
It is a figure which shows the relative opening curve of the inlet valve which concerns on embodiment of FIG. 6A.
8 is an enlarged view of a third embodiment of a control means according to the present invention.

1 is a diagram showing a schematic diagram of a piston engine 1 according to the understanding of the present invention. Gas exchange of the cylinder (not shown) of the piston engine 1 is carried out under the control of a gas exchange valve, that is, an inlet valve and an exhaust valve, located in the cylinder head 2. Only the inlet valve 3 is shown, which is operated by a valve mechanism which is normally guided by the cam profile 5 'of the cam device 5 which is configured on the cam shaft 4 of the engine. The force transmission connection between each valve mechanism 6 and the corresponding cam device 5 is realized by the control arrangement 7.

The control component 7 is shown in more detail in FIGS. 2 to 4, which shows a non-operational state, whereby the inlet valve 3 associated with the control component is closed. The control structure 7 comprises the main body part 8 which is normally attached to an engine main body. The piston device 9 is configured to be movable in the body portion 8. The upper end of the piston device 9 is configured in force transmission connection with the valve mechanism 6. This connection is mechanical in this case, but it can also be hydraulic. The movement of the piston device 9 is controlled by the guide member 10 configured at the lower end of the piston device in the body portion 8. The guide member 10 is engaged with the spring 11 and urged towards the roller 12 by the spring, which roller guides from the cam profile 5 'of the cam device 5. Receive. Thus, when the cam shaft 4 rotates, in the clockwise direction in FIGS. 2 to 4, the roller 12 follows the cam profile 5 ′ of the cam device 5 and the cam profile 5 ′ of the cam profile 5 ′. The change is communicated affecting the opening and closing of the inlet valve 3.

The main body 8 and the piston device 9 define the first chamber 13 together, in which the conveying duct, as indicated by the arrows, provides a delay in closing the inlet valve 3 with the hydraulic medium. It can be selectively transported through 14. In practice the transfer duct is advantageously provided with shut off valves and non-return valves, which are not shown. The transfer line to the first chamber 13 by means of a shut-off valve can be connected or disconnected depending on whether or not it is intended to use a delay function for delayed closing of the inlet valve 3. The non-return valve prevents the control component from causing any pulsation at the source of the hydraulic medium. This is important when lubricating oil is used as the hydraulic medium.

The body part 8 is additionally provided with ducts 15 and 18, whereby the first chamber 13 can be connected with a second chamber 19 located in the guide member 10. The guide member 10 is provided with a hole 10a for this purpose. The flow connection between the chambers 13 and 19 is established when the hole 10a is in the position of the lower end opening of the duct 18. In addition, between the ducts 15 and 18 there is a chamber 16 or similar duct comprising the control means 17 according to the invention, the construction and operation of which are described in more detail below.

In FIG. 2 the control component 7 is in an inoperative state and the roller 12 is located in the basic circle of the cam profile 5 ′. In FIG. 3, the cam device 5 is rotated clockwise so that the nose of the cam profile 5 ′ lifts the roller 12 upward in the drawing. Thus, also the guide member 10 and the piston device 9 have been moved upwards and as a result the corresponding inlet valve 3 (not shown) is opened. At the same time the first chamber 13 is filled with hydraulic medium which is conveyed through the transfer duct 14.

In FIG. 4 the roller 12 is returned to the basic circle of the cam profile 5 '. Thanks to the hydraulic medium of the first chamber 13 the piston device 9 once remains in its normal position, whereby the inlet valve also remains open. As can be seen in FIG. 4, the connection between the piston device 9 and the guide member 10 is thereby separated. Thereafter, when the hole 10a of the guide member 10 is moved to the open position of the duct 18, the pressure of the first chamber 13 is released and the piston device 9 starts to move downward in the figure. Thereby enabling the inlet valve to also be closed. Then also the contact between the piston device 9 and the guide member 10 is reestablished. Hydraulic medium flows further from the chamber 19 into the oil sump, which provides lubrication for the cam shaft and the parts connected thereto.

When the variable inlet valve closing (VIC) function associated with the chamber 13 is not used, the piston device 9 is in continuous connection with the guide member 10 and the communication between the chamber 13 and the chamber 19 is normal. Is established in such a way.

5 shows a first embodiment of the control means 17 according to the present invention. The chamber 16 is provided with three ducts 18a, 18b and 18c, each of which comprises a control valve 17a which is movable in the chamber 20 located in the body portion 8. It can be configured to communicate with the chamber 19 through the hole (10a) by. The control valve 17a is provided with a valve member 17b and a release means 17c, in which case the release means is a groove circumventing the valve member 17b. In Fig. 5 the release means 17c is in the position of the duct 18b, whereby communication between the chambers 13 and 19 is established through this duct 18b. As is apparent from the figure, the end openings of the ducts 18a, 18b and 18c are at different heights. This means that during the movement of the guiding member 10 the end openings of this duct will be at the positions of the holes 10a at different times, whereby the release of pressure in the chamber 13 will each occur at a different time. This thus entails a different delay in the closing of the inlet valve depending on the duct selected in each case.

The operation of the valve means 17 can advantageously be achieved pneumatically by transferring pressure air into the chamber 20, as indicated by the arrow, which springs the control valve 17a with the valve member 17b. This will result in pressing to the left in the drawing against the force of (21). Thus, the movement of the control valve 17a and the selection of the respective ducts 18a, 18b and 18c differ depending on the pressure of the air delivered into the chamber 20. The control system of the engine should preferably be such that the charge air from, for example, the turbocharger of the engine is used. The fluctuation in closing the inlet valve can thereby be achieved approximately automatically as a function of the different charge air pressure depending on the load of the engine in each case.

6A and 6B describe another embodiment of the control means 17 '. In this case the chamber 16 'formed as a connecting duct is operatively connected with the control valve 17'a, the control member 17'b of which is connected to the chamber 16' and the second duct 18'b. To control communication between. The control valve 17'a is located in the chamber 20 'where pressure air is conveyed to press against the force of the spring 21'. As shown in FIG. 6B, when the connection between the chamber 16 'and the duct 18'b is closed, communication between the chambers 13 and 19 is established through the duct 18'a. As shown in FIG. 6A, on the other hand, when the connection between the chamber 16 'and the duct 18'b is opened, communication between the chambers 13 and 19 is established earlier through the duct 18'b. And its end opening is above the end opening of the duct 18'a. However, also in this case the duct 18'a remains open and it is not necessary to have a separate control valve to close it.

Its effect on the operation of the embodiment of FIGS. 6A and 6B and the delay of the closing of the inlet valve of the engine is shown in FIG. 7 showing the relative opening curve of the inlet valve as a function of the cam angle of the engine. Curve C shows the situation where no hydraulic medium is guided to the chamber 13, whereby the inlet valve control is determined and executed only by the cam profile 5 ′. Curves A and B relate to the situation where the hydraulic medium is guided to the chamber 13 and the piston device 9 moves in the opening direction of the inlet valve. It is thus possible, for example, to provide a delay in closing the inlet valve to its normal operation in different load situations of the engine. Curve A shows that when the delay is influenced by selecting communication between the chambers 13 and 19 through the duct 18'a, the control valve 17'a is thus shown in FIG. 6B. 'b) is a situation of closing position. Curve B then shows the situation corresponding to FIG. 6A, whereby the control valve 17 ′ a is opened and enables communication through the duct 18 ′ b. Thereby the release of the pressure in the chamber 13 occurs earlier, so that the inlet valve also closes earlier, but the closure is still delayed in comparison with the normal situation described by the curve (A).

It is a figure which describes 3rd Embodiment of the control means of this invention. This is a variation of the embodiment of Figures 6A and 6B and includes a third duct 18 "c in addition to the ducts 18" a and 18 "b. As can be seen, each end opening of this duct is different. Located at different positions along the height, ie the return movement of the guide member 10, thereby providing the possibility for varying the delay of the closing of the inlet valve. Depending on the need for a more precise variation of the delay available in each case for the closing of the, and according to the available space of the body part 8 of each engine.

In the case of the embodiments of FIGS. 6A, 6B and 8 the control valves 17, 17 ′ and 17 ″ can preferably be operated by any pressure medium available in the engine, ie pneumatically, hydraulically or also electrically. The choice of control and flow duct of the control valve in each case can be configured by using the pressure sensor and appropriate control logic for each control valve to determine the required delay in each case and thus ensure the correct operation of the control valve. Done.

The invention is not limited to the above-mentioned embodiments but may be practiced in many other different embodiments within the spirit of the invention and the scope of the appended claims.

Claims (9)

Inlet valve of a piston engine suitable between the cam device 5 of the cam shaft 4 of the engine 1 and the inlet valve mechanism 6 configured to open and close the inlet valve 3 associated with the cylinder of the engine. As a control element for the control element 7, the control element 7 comprises a body portion 8 which is configured to be movable such that the piston device 9 is in force transmission connection with the cam shaft 4 and the valve mechanism 6. The main body 8 and the piston device 9 are connected to the first chamber via a first chamber 13 through which hydraulic medium can be selectively transferred, and through duct means 18, 18 ′, 18 ″. A control arrangement which defines together the second chamber 19 to be connected and the flow of hydraulic medium from the first chamber 13 to the second chamber 19 is controlled to provide a delay in closing the inlet valve 3. To
The body portion 8 has at least two flow ducts 18a, 18b, 18c; 18'a, 18 to constitute different routes for the flow of hydraulic medium from the first chamber 13 to the second chamber 19. 'b; 18 " a, 18 " b, 18 " c are provided, and control means 17, 17', 17 " are used to select the route of flow used in each case to provide different closure delays. Control arrangement, characterized in that provided for. 2. The apparatus of claim 1, wherein the two or more flow ducts 18a, 18b, 18c; 18'a, 18'b; 18 "a, 18" b, 18 "c are configured to communicate with the first chamber 13 Configured to open in a common chamber 16, 16 ′, 16 ″ or similar connecting duct, and control means 17, 17 ′, 17 ″ or the common chamber 16, 16 ′, 16 ″ or its Control arrangement, characterized in that it is configured to operate in a connection duct. The guide member (10) according to claim 1 or 2, wherein the second chamber (19) is constituted between a cam device (5) and a piston device (9) movable in correspondence with the movement of the cam device (5). ), And the two or more flow ducts 18a, 18b, 18c; 18'a, 18'b; 18 "a, 18" b, 18 "c differ depending on the trajectory of the movement of the guide member 10. A control component, configured to open into the second chamber (19) in position. 4. Control arrangement according to claim 3, characterized in that the guide member (10) is configured to act directly on the piston device (9) only in the direction for opening the inlet valve (3). 5. The flow according to claim 1, wherein the flow of the hydraulic medium is configured through one of the flow ducts 18a, 18b, 18c at a time and the control means 17 comprises the flow duct (5). And a control valve (17a) having a movable valve member (17b) provided with release means (17c) configured at one of the positions of 18a, 18b, 18c. 6. Control arrangement according to claim 5, characterized in that the release means (17c) are narrowing parts having dimensions such that they flow through only one duct (18a, 18b, 18c) at a time. 5. A separate control valve 17'a, according to any one of the preceding claims, for each flow duct 18'b; 18 "b, 18" c to provide a shortened delay time. 17 " a). 8. The control means according to any one of the preceding claims, wherein the control means 17, 17 ', 17 "are preferably operated pneumatically by using a control system included in the engine, against the force of the spring. Control arrangement, characterized in that configured. 9. Control arrangement according to claim 8, characterized in that the charge air from the turbocharger of the piston engine is configured to be used for controlling the control means (17, 17 ', 17 ").

Images