FI123927B - Control arrangement for a suction valve in a piston engine - Google Patents

Abstract

The invention relates to a control arrangement for an inlet valve in a piston engine adapted between a cam device (5) of a camshaft (4) of the engine (1) and an inlet valve mechanism (6) arranged to open and close the inlet valve (3) in association with a cylinder of the engine. The control arrangement (7) comprises a body part (8), in which a piston device (9) is movably arranged to be in force transmission connection with the cam device (5) and the valve mechanism (6), and a guide member (10) arranged in the body part (8) between the cam device (5) and the piston device (9) to be movably responsive with the movements of the cam device (5). The body part (8) and the piston device (9) define together a first chamber (13), into which hydraulic medium can be selectively fed. The flow of hydraulic medium out from the first chamber (13) is controlled for providing a delay in the closing of the inlet valve (3). The control means for controlling the releasing of pressure in the first chamber (13) include a bevel control surface (19a;25a;25'a;29a) arranged for changing the timing of the releasing of pressure in the first chamber (13).

Description

Piston Engine Intake Valve Control System Technical Field

The invention relates to a suction valve control arrangement for a piston engine 5 according to the preamble of claim 1.

Background technology

In the case of four-stroke internal combustion engines, there are situations where the cylinders do not receive enough air to spontaneously ignite during the compression stroke. This pi-10 is especially true during engine start-up and load variations for high-pressure supercharged engines such as two-stage turbocharged engines. These types of motors utilize higher pressures in combination with sharper or shorter nose tip shapes, which results in the supercharging operation occurring in 15 shorter times, respectively. The opening times of the suction valves under normal engine load are thus not long enough for such special situations.

One solution to provide sufficient air in the cylinder for compression ignition to occur is to provide a delay in suction valve closure to extend the suction valve opening time if necessary. Known solutions for such an adjustable 20 suction valve closure (VIC) have been disclosed, for example, in WO 2008/000899.

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It is an object of the invention to provide a further improved control system for piston engine gas exchange, which provides

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More opportunities to use the delay function in 25 stages of suction valve closures. The invention is particularly intended for use in the turbocharged internal combustion engines referred to above, so that the problems of inadequate supply air, which occur in engines when used, for example, at low engine loads and during engine start-up, can be addressed and thus optimally addressed.

DISCLOSURE OF THE INVENTION The objects of the invention may be substantially achieved as set forth in claim 1 and more particularly in the other claims, which further detail the various embodiments of the invention.

The basic idea of the invention is to enable adjustable timing of the delay function during the closing of the suction valve in order to better meet the particular conditions. According to the invention, this is accomplished in practice so that the control means for controlling the release of pressure in the first chamber include an oblique control surface arranged to vary and adjust the timing of the release of pressure in the first chamber.

The guide means is preferably arranged in a member which can be moved back and forth under the direction of the cam device in the direction of lifting to control the flow through the outlet pipe in connection with the first chamber. In order to effect the adjustment, the control means are arranged to be rotated about its axis of movement to change the position of the sloping guide surface relative to the outlet pipe 20 and thus to change the timing of pressure release in the first chamber.

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In one embodiment, the control means comprises a rotatable piston member,

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9 which is controlled by the control member, wherein said piston member is arranged to move in a direction transverse to the outlet flow pipe through the piston member.

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£ 25 to control it. In this case, the control member presses against the force of the spring of the piston member as the control arrangement moves in the direction intended to raise the suction valve.

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In another embodiment, wherein the first chamber is connected to the second chamber via an outlet pipe, the control member selectively controls the opening of the outlet pipe leading to the second chamber. In this case, the control means are arranged in connection with the control member in practice preferably so that the control means are arranged in a sleeve member rotatably connected to the control member. The guiding means include a gap arranged in the sleeve member and extending transversely to the outlet of the outlet pipe 5 to direct the flow therethrough. The mutual position between the outlet and the gap of the outlet pipe can then be adjusted by rotating the sleeve member about its axis.

In practice, the slot may preferably be triangular and arranged such that the sharp-angled one end corresponds to a maximum delay in suction valve closure and the triangular flank-like end extending substantially in the suction valve lifting direction corresponds to a no delay condition. Said sharp angle and said side of the triangle are then interconnected by a sloping guide surface. In this case, the control means alone can provide full control from the maximum delay to the minimum delay, whereby the minimum delay corresponds to no delay at all.

The control means include a gap, arranged transversely to the opening of the outlet member, which is arranged in the guide member and which controls the flow of a gap therethrough. The control member can be rotated about its axis to change the mutual position between the outlet of the outlet pipe and the slot.

In yet another embodiment, the control means comprise a separate piston element arranged between the piston device and the control member. The outlet flow is passed through said piston element. In this case, the piston element is arranged to be rotatable about its axis to change the mutual position between the outlet pipe and the piston element.

cc »o i cj 25 The malignant discharge stream is led from the first chamber to the discharge stream downstream of the pipe and guiding means into the hydraulic fluid supply line of the first chamber for recirculation to the first chamber and / or for utilization in other pressure medium systems and devices of the engine.

In practice, adjusting means, preferably an adjusting shaft, for providing a rotational movement of the steering means are provided. The control means are movably supported on the 4 body parts and are controlled by the control unit to achieve optimum timing of the suction valve closing delay, taking into account the respective engine operation. One or more or all of the motor suction valves can be controlled and adjusted simultaneously.

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Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: - Figure 1 shows a piston engine and a schematic diagram of its valve mechanism, 10 - Figure 2 shows a first embodiment of a control arrangement according to the invention; 3 is a detail view of D in Fig. 3, and - Fig. 4 shows a third embodiment of a control arrangement according to the invention, - Fig. 5 shows a fourth embodiment of a control arrangement according to the invention in a situation corresponding to a maximum delay of closing the suction valve of the motor;

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g - Figure 5a shows section A-A of Figure 5,

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o 20 - Figure 5b shows a section B-B of Figure 5,

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x - Fig. 6 shows the control arrangement of Fig. 5 in a second operating position,

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^ - Fig. 6a shows a section C-C, 1 ^ m O) of Fig. 6 - Fig. 7 shows a control arrangement of Fig. 5 in a third operating position,

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Fig. 7a shows a section DD of Fig. 7, Fig. 8 shows a control arrangement of Fig. 5 in a fourth operating position, - Fig. 8a shows a section EE of Fig. 8, - Fig. 9 illustrates an embodiment of Fig. 5 in a situation corresponding to a minimum suction valve closing time; Figure 9a shows a section A'-A 'of Figure 9, - Figure 9b shows a section B'-B' of Figure 9, - Figure 10 shows a control arrangement of Figure 9 in a second operating position, - Figure 10a shows a section C'-C 'of Figure 10, Fig. 11 shows the control arrangement of Fig. 9 in the third operating position; 10 - Fig. 11a shows a section D'-D 'of Fig. 11.

Detailed description of the drawings

Figure 1 is a schematic view of a piston engine 1 insofar as it is relevant to an understanding of the invention. The gas exchange of the cylinders (not shown) of the piston engine 1 is effected by means of gas exchange valves located on the cylinder head 2, i. controlled by suction and exhaust valves. Only suction valves 3 are shown and are actuated by valve mechanisms 6, which are typically controlled by cam sprockets 5 'of cam means 5 provided on the cam 4 of the motor.

The transmission connection 20 between each valve mechanism 6 and the corresponding cam device 5 is implemented by a control arrangement 7.

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The control arrangement 7 is illustrated in more detail in Figures 2-4, which illustrate various embodiments of the invention. The control arrangement 7 comprises a body part 8 which is typically attached to a motor body. The piston device 9 is arranged movably within the body part 8. The upper end of the piston device 9 is provided for transmission engagement with the valve mechanism 6 (not shown). This connection may be mechanical or hydraulic. The movements of the piston device 9 are controlled by a control member 10, 6 disposed at the lower end of the piston device 9 within the body portion 8. The guide member 10 engages with a spring 11 and is forced by it against a roll 12 which is controlled by the cam profile 5 'of the cam device 5. As the camshaft 4 rotates, in FIGS. 2-4 counterclockwise, the roll 12 thus follows the cam profile 5 5 'of the cam device 5, and changes in the cam profile 5' are transmitted to cause the suction valve 3 to open and close.

The body 8 and the piston device 9 jointly define a first chamber 13 into which the hydraulic medium can be selectively supplied through the feed pipe 14 to provide a delay in the closure of the suction valve 3. The supply line is provided with a non-return valve 15, a shut-off valve 16 and pump means 17. The shut-off valve 16 allows the supply line leading to the first chamber 13 to be connected or disconnected depending on whether it is intended to operate delayed or not. Due to the non-return valve 15, the control arrangement cannot cause pulsations at the source of hydraulic fluid 15. This is important when using lubricating oil as the hydraulic medium. With respect to the overall operation of the delay function, reference is made in itself to WO 2008 / 000899A1, which is incorporated herein by reference, which describes some alternative means of implementing such an arrangement in general, and its operation.

The cam profile 5 'includes a cam 5' which extends upwardly from the base circumference and is arranged to move the piston device 9 in the figures upwardly to cause the suction valve 3 to open. In the embodiments shown in Figs. 2-4, the cam profile 5 'further includes a part arranged below the base. This is generally utilized to determine the end of a delay function corresponding to a reduction in the pressure in the first chamber 13, whereby the present invention provides control over the timing of the suction valve closing step. The significance of the disclosed cam profile is explained in more detail in Finnish Patent Application No. 20085756, but because it does not

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0 is not directly related to the present invention and the present invention can also be applied independently, its operation will not be described in more detail herein.

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The body part 8 is further provided with an outlet conduit 18 for relieving pressure in the first chamber 13 to close the suction valve 3. The invention relates to a more precise control of the release of pressure in the chamber 13.

For this purpose, according to the embodiment of Figure 2, a piston member 19 is provided which includes an opening comprising a bevelled guide surface 19a. The hydraulic medium in the chamber 13 can thus be passed through the outlet flow pipe 18 through the piston member 19 and further away through the flow pipe 18a. The pressurized discharge flow from the tube 18a can be further utilized in the motor if desired. In particular, it may be introduced into the hydraulic pressure medium supply line of the chamber 13 to be fed back into the chamber 13 to provide the delay function of the suction valve. In addition, or alternatively, it can be utilized in other pressure medium systems and devices of the engine. These alternatives are only shown schematically by arrows in connection with the dashed line in Figure 2.

The control member 10 guides the piston member 19 by pressing it upwardly against the spring 20 during the lifting movement associated with the opening of the suction valve after the situation of Figure 2. The piston member 19 can be rotated about its axis by means of a tooth clamp 21 arranged to cooperate with an adjusting shaft 22 which is moved in its axial direction to rotate the piston member 19. In order to release the pressure in the chamber 20 13, it is thus possible to adjust the exact moment at which the opening in the piston member 19 with a sloping guide surface 19a moves to the outlet flow pipe 18 forced by a spring 20 during the return movement of the piston device 9 ". The control unit 34 controls the movements of the control shaft 22 for optimal timing of the delay in suction valve 3 closure, taking into account the respective motor operation.

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According to the embodiment of Fig. 3, the outflow pipe 18 connects the first chamber 13 to the second chamber 23, which is delimited by the body part 8 and the control member m 10 and where the lower end of the piston device 9 is located. The spring 11 is also located in the o ™ 30 in this second chamber 23.

8 In this case, the control means are arranged in a sleeve member 24 which is pivotally connected to the guide member 10 to control the opening of the conductive outlet pipe 18. As can be best seen in Figure 3a, the control means include a slot 25 disposed in the sleeve member 24, which extends across the opening of the drainage conduit 18 for transverse flow therethrough by means of a bevelled guide surface 25a. The mutual position of the outlet pipe 18 between the opening and the slot 25 is in turn controlled by rotating the sleeve member 24 about its axis by means of a toothed groove 26 and an adjusting shaft 27 provided on the sleeve member 24. As can be seen from the drawing, the second chamber 10 is provided with outlet pipes 28 for further directing the hydraulic medium to, for example, the engine oil pump.

In the embodiment of Figure 4, the control means comprise a separate piston element 29 disposed between the piston device 9 and the control member 10, the hydraulic fluid from the outlet flow pipe 18 is guided through an opening 15 in said piston element 29 with a sloping guide surface 29a. In this case, the piston element 29 is arranged to be rotated about its axis by the wedge means 30 arranged in the piston element 29 and the adjusting shaft 31 to change the mutual position 20 between the opening of the outlet pipe 18 and the opening in the piston element 29. Similarly to the embodiment of Figure 2, in this case also, the pressurized discharge stream from pipe 18a may be recycled to be fed to chamber 13 and / or utilized in other pressurized media systems and devices of the pressurized medium.

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Figures 5 to 11 relate to a fourth embodiment of the invention, which is essentially similar to that of Figure 3. In this case, however, the arrangement for rotating movement of the sleeve member 24 'differs so that the adjusting shaft 33 g is provided with a transverse groove 33a having a guide pin 32 attached to the sleeve member 24'. which can then be rotated between two O) § 30 end positions corresponding to the selected suction valve closing time

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tusviivettä. The arrangement comprising the transverse groove 33a also allows the mutual movement of the guide pin 32 and the adjusting shaft 33 during the suction valve lifting movement. This 9 is also true for the arrangements illustrated in Figures 2 to 4, since the tooth pressing is dimensioned long enough in the direction of lifting movement.

Another difference compared to the embodiment of Fig. 3 is the shape of the slot 25 ', which in this case is essentially triangular and arranged on the sleeve member 24' 5 such that the sharply angled one end corresponds to the maximum delay in suction valve 3 closure not implemented. This slot 25 'is then provided with an oblique guide surface 25'a which connects the sharp corner and the sides of the triangle as shown in the figures, thereby providing stepless control of the delay function.

Figures 5 to 8 and 5a to 8a illustrate the operation of the arrangement at various stages of operation in a situation corresponding to a maximum delay in closing the suction valve of the motor. As shown in particular in Figures 7a and 8a, the outlet of the drainage pipe 18 is located near a sharp angle in the slot 25 ', which provides a maximum-15 delay. Further, as shown in Figure 7, there is a clearance between the piston device 9 and the control member 10 as long as the delay function is active.

Figures 9-11 and 9a-11a, on the other hand, illustrate the operation of the arrangement, respectively, at various stages of operation in a situation corresponding to a minimum delay in closing the suction valve of the motor. After the position of Figure 11, the roller 12 20 returns to the base circumference of the cam device 5, whereby the positions of the various parts correspond to the positions of Figure 9.

As can be seen in Figure 11 showing the suction valve closing step, there is no clearance between the piston device 9 and the control member 10. In this case, the minimum delay thus also represents a situation in which no water is provided at all. In this case, the shut-off valve 16 (cf. Fig. 2) does not have to be used for the delay function | but this can be advantageously accomplished by a suitable structure o of the guide means, m o The cam profile 5 'of the cam device 5 having a cam 5' is in this case

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™ is elongated and suitable, in addition to those shown in Figures 2-4, for use in the control arrangement of the invention.

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The invention is not limited to the embodiments disclosed, but various modifications are possible within the scope of the appended claims.

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Claims (10)

A control arrangement for a suction valve in a piston engine arranged between a cam assembly (5) on the camshaft (4) of the engine (1) and a suction valve mechanism (6), the suction valve mechanism being arranged to open and close in conjunction with the engine cylinder a suction valve (3), comprising a control arrangement (7) comprising a housing part (8), which is provided with a piston device (9) for movable locking in a power transmission connection with the cam device (5) and the valve mechanism (6), and a control means (10). arranged in the housing part (8), between the cam device (5) and the piston device (9), to move according to the movements of the cam device (5), the said housing part (8) and the piston device (9) jointly defining a first chamber (13). ) to which hydraulic medium can be selectively measured, controlling the flow of the hydraulic medium from the first chamber (13) to effect a delay in the closing of the suction valve (3), the control means for controlling the release of the pressure in the the first chamber (13) has an oblique guide surface (19a; 25a; 25'a; 29a) which is arranged to change the timing of releasing the pressure in the first chamber (13), characterized in that the control means are arranged at a member (19; 24; 29) controlled by the cam device (5) can be moved to move moving back and forth in the direction of the lifting motion to control the flow through a drain flow tube (18) arranged in conjunction with the first chamber (13), and that the control means comprise a pivotal piston member (19) which is controlled by the control means (10), said piston member (19) is arranged to move transversely in relation to the effluent flow tube (18) to control the flow conducted through the piston means (19). Control arrangement according to claim 1, characterized in that the control means are pivotable about their axis of movement to change the position of the oblique guide surface (19a; 25a; g 25'a; 29a) in relation to the effluent flow tube (18) and thereby change the timing. for releasing the pressure in the first chamber (13). CC Control arrangement according to claim 1 or 2, characterized in that the control means (10) presses the piston member (19) against the force of a spring (20) as the control arrangement LO moves in the lifting direction of the suction valve (3). o C \ 1 Control arrangement according to claim 1 or 2, characterized in that the first chamber (13) is connected to a second chamber (23) by mediating the drain flow tube (18), that the control means (10) controls the orifice of the second chamber. (23) the conductive effluent flow tube (18) selectively and that the control means are arranged in conjunction with the control means (10). Steering arrangement according to claim 4, characterized in that the steering means are arranged at a sleeve member (24; 24 ') which is rotatably coupled to the steering means (10), that the steering means comprises a slot (25; 25') arranged in the sleeve means ( 24; 24 ') and extending transversely to the orifice of the effluent flow tube (18) to control the flow therethrough, adjusting the mutual position between the orifice of the effluent flow tube (18) and the gap (25; 25') by the sleeve member (24; 24 ') around its axis. Control arrangement according to claim 5, characterized in that the gap (25 ') is triangular and arranged so that one end having the shape of an acute angle corresponds to the maximum delay in the closing of the suction valve (3), and the other end having the shape of a triangular side and extending substantially in the lifting direction of the suction valve (3) corresponds to a situation where the delay is not carried out, wherein said acute angle and said triangular side are joined by the oblique guide surface (25'a). Control arrangement according to claim 1 or 2, characterized in that the pivotal piston member of the control means comprises a separate piston element (29) arranged between the piston device (9) and the control means (10), the wastewater flow being controlled by said piston element (29). co Control arrangement according to claim 7, characterized in that the piston element ° (29) is arranged to be rotated about its axis to change the relative position between the o drainage flow pipe (18) and the piston element (29). C \ J x 25 Control arrangement according to claim 1, characterized in that the pressurized waste CC flow from the first chamber (13) after the drain flow tube (18) and 0 P; the control means are guided to the hydraulic fluid supply line to the first chamber (13) LO 0 to be circulated back to the first chamber (13) and / or to be used in the other pressure media systems and devices of the 00 engine. Control arrangement according to claim 2, characterized in that it is provided with adjusting means, preferably with an adjusting shaft (22; 27; 31; 33), for carrying out the rotary movement of the control means, said adjusting means being movably supported against the housing part (8) and is controlled by a control unit (34) to achieve an optimum time setting for the delay in the closing of the suction valve (3), taking into account the operation of the engine at each occasion. CO δ c \ j CD O CVJ X tr CL O h- h- LO CT) O o CVJ