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(11) | EP 0 619 418 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
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| (54) | METHOD AND MECHANISM FOR GAS DISTRIBUTION IN FOUR-STROKE INTERNAL COMBUSTION ENGINE WITH PHASE REGULATION |
| (57) A method of gas distribution in a four-stroke internal combustion engine with phase
regulation and a device for its implementation are intended for ensuring optimal phases
of gas distribution under all speed working conditions of the engine and thus increasing
its power-economic and dynamic characteristics. The phase regulation is effected by
means of angular shift of the camshafts (1, 2) in relation to the crankshaft (10),
whereas in case of increase of rotation speed one camshaft (1) is shifted in the direction
of its rotation and the other camshaft (2) against the direction of its rotation.
A mechanism for gas distribution in a four-stroke internal combustion engine with
phase regulation comprises two camshafts (1, 2) controlling the inlet (3, 4) and outlet
(5, 6) valves by means of cams, and further comprises a device for angular shifting
of the camshafts (1, 2) in relation to the crankshaft (10) by means of influencing
a driving-element (7) with actuating mechanisms (15, 16) interconnected through a
control unit (14) and provided with rollers (11, 12). |
Field of Technics
[0001] The invention relates to mechanical engineering namely to a method of gas distribuion in a four-stroke internal-combustion engine with phase regulation and a mechanism for realization thereof.
Background of the Invention
[0002] It is known a mechanism of gas distribution in a four-stroke internal-combustion engine with changeable phases (SU Application No 1634809), containing a disk valve with springs and pusher, a hollow can shaft with two cams for each valve which provide phases of gas distribution. In the shutting-off state one cam is connected with the shaft through the torsion spring with possibility a relative angular shift, and in the engaged state through the rigid connection coupling which is carried out as a whole together with the cams of the cam shaft. Another cam is fastened on the shaft fixed.
[0003] At the low rotation frequency phase diagram of gas distribution in the engine is defined by an action of fixed cam, and controllable cam makes small angular oscillations in relation to fixed cam (rotating by this together with the cam shaft) which are effected by a difference of these cam profiles. At the high rotation frequency fixed connection of controllable cam with the fixed cam and hence with the cam shaft is obtained. From this moment phase diagram of gas distribution in the engine is defined by the controllable cam which has more "full" profile than the fixed cam.
[0004] Regulation of the gas distribution phases by this method can provide optimum duration of the phases for two speed modes of the engine action only, but at the rest range of the rotation frequencies a duration of the phases of gas distribution will not be optimum, and in these modes the engine power and hence dynamic characteristics will not reach their maximum values.
[0005] To the shortcomings of said mechanism should be refered: sharp increasing of the specific pressure at the areas of the primary contact of the cam connecting elements in the moment of the switching, what will result in their speeded up wear, complicacy of the design because of the presence of the elements which demand particular attention during their manufacturing and handling in particular fixation of the springs on the controlling rod and the fixed cams on the cam shaft (particularly in the multi-cylinder engines), interaction of the controllable cam with the movable bush and with the spring which fastens it on the cam shaft, considerable remoteness of the spot of the cam contact from the valve axis. The above-mentioned shortcomings essentially decrease reliability and longevity of the sai mechanism of gas distribution.
[0006] It is known a mechanism of gas distribution in a four-stroke internal-combustion engine with changeable phases (GB Application No 2228533) containing two cam shafts, inlet and outlet valves, the latters deviding on the main and supplementary. The first cam shaft is provided with the cams for controlling all outlet valves and main inlet valves, and the second one for controlling supplementary inlet valves only. There is a mechanism for change of the phase of the second cam shaft in relation to the first one.
[0007] It is proposed versions of engine arrangings, in particular, in one of its all outlet valves and main inlet valves are disposed by one side from the engine and are controlled with the cams of the first cam shaft, and the supplementeary inlet valves are disposed by the another side from the engine and are controlled with the cams of the second cam shaft.
[0008] In according to the another version the outlet valves are disposed by one side from the engine, and all inlet valves by another side from one, main inlet valves controlling with the cams of the first cam shaft through the arms.
[0009] To the shortcomings of this decision should be refered absence of the phase regulation of the opening of the outlet and main inlet valves. Said method can provide enlarging of the inlet phase duration in one direction only. For example, if a supplementary inlet valve begins to open (and then to close) earlier by the increasing of the rotation frequency, the end of the inlet phase is defined by the moment of the closing of the main inlet valve and remains without change whereas for improvement of the engine characteristics by the increasing of the rotation frequency it is important not only to open the valve earlier, but tj close it later, it is important for the outlet valves also.
[0010] To the shortcomings of the device according to the first version of the arranging should be refered presence of only one outlet valve per cylinder, what limits essentially possibility of the engine forcing with the multi-valves head, and decreases its power-economical and dynamical characteristics.
[0011] According to the next version of the arranging the engine is provided with two inlet and two outlet valves per each cylinder, what improves its characteristics in comparison with the first version, but by this controlling the main inlet valve through the arm results in complication and rice in price of the design, decreases its reliability and also limits possibilities for the engine forcing according to the rotation frequency, what is actual for the engines with the multi-valves heads.
Disclosing of the invention
[0012] The ground of the invention is the task to create a method of gas distribution in a four-stroke internal-combustion with phase regulation and a mechanism for realization thereof, wherein owing to introduction of new actions and construction elements which carry out these actions and provide phase change of action of separate valves is reached enlarging of the inlet and outlet phase duration by increasing of rotation frequency, what in result increases the power-economical characteristics of the engine and permits to enlarge the work range of the rotation frequency, to decrease turns of the idling and starting turns.
[0013] Essence of the invention consists of in a method of gas distribution in a four-stroke internal-combustion engine with phase regulation consisting of rotation of the cam shafts with possibility of their angular shift in relation to the crankshaft in according to work mode of the engine, according to the invention, an angular shift of one cam shaft is carried out in the direction of its rotation, and of the other cam shaft against the direction of its rotation.
[0014] An angular shift of one cam shaft in the direction of its rotation and other one against the direction of its rotation permits to enlarge duration of closing period of the valves by the enlarging of the rotation frequency of the crankshaft. This occurs owing to the valves as well inlet as outlet which are controlled with one cam shaft begin to open earlier and hence to close earlier, and ones which are controlled with the other cam shaft to open laster and to close laster. Thus the period of the opening of at least one valve ( from the same names) increases by the value of the total angular shift of the cam shafts in relation to the crankshaft, what provides enlarging of inlet and outlet phase duration in the engine at the incraesing of rotation frequency, and this in result increases the power-economical and dynamical characteristics of the engine, permits to enlarge the work range of the rotation frequencies, to decrease the turns of the idling and the starting turns.
[0015] Essence of the invention also consists in that for realization of said method a mechanism of gas distribution in four-stroke engine with regulable phases is used which contains two cam shafts controlling inlet and outlet valves through the cams, and a device for carring out of angular shift of the cam shafts in relation to crankshaft which connects with the cam shafts through the driving element, according to the invention, the device for carring out of angular shift of the cam shafts connects with the both cam shafts and provides shift of one cam shaft in the direction of its rotation, and the other cam shaft against the direction of its rotation.
[0016] This provides the earlier opening of the inlet and outlet valves which are cjntrolled with the first cam shaft and the later closing of the inlet and outlet valves which are controlled with the second cam shaft, what in cjmbination results in enlarging of the inlet and outlet phase duration at enlarging of the rotation frequency.
[0017] It is expedient to execute the device for carring out of angular shift of the cam shafts at change of the rotation frequency in form of two actuating mechanisms interconnecting through the control unit and providing with the rollers which are in contact with the driving element connecting the crankshaft with the cam shafts, one roller contacting with the driving element at the loaded zone connecting the crankshaft with one of the cam shafts, and the other roller is in contact with the driving element at the zone between the cam shafts.
[0018] The rollers which state, depend on speed mode of engine actuation, is given by the control unit through the actuating mechanisms contact with the driving element and transmit the efforts from the actuating mechanisms acting to the driving element and providing a certain caving of its parts and hence defining the lengths of these parts, what in the turn defines exactly a mutual angular displacement of the cam shafts and the crankshaft.
[0019] Obviously that it is necessary to acting only to the loaded zones of the driving element. Its oscillations at the unloaded zone are declined by means of the tension roller.
[0020] The invention will now be described further by detail dedescription of the pfrticular version of realization thereof and the accompanying drawings.
Brief description of the drawings
[0021]
Figure 1 is a schematic representation of view from above of the engine, one cylinder;
Figure 2 shows a simplified front view of the engine;
Figure 3 is a representation of diagrams of dependence of inlet valves run from a rotation angle of the crankshaft.
Preferable version of realization of the invention
[0022] A method of gas distribution in a four-stroke internal-combustion engine with phase regulation consists of rotation of the cam shafts with possibility of their angular shift in relation to the crankshaft depend of speed mode of the engine work. An angular shift of one of the cam shifts is carried out in the direction of its rotation, and of the other cam shaft against the direction of its rotation.
[0023] The proposed mechanism of gas distribution in a four-stroke internal-combustion engine with phase regulation contains two cam shafts 1 and 2 (Fig.1) tfch of which is provided with cams for controlling the inlet valves 3,4 and the outlet valves 5,6, a driving element 7 (Fig.2) of the cam shafts 1,2, e.g. a belt, pulleys 8,9 of the cam shafts 1,2 and crankshaft 10. Two rollers 11 and 12 contact with the driving element 7, one of the rollers is displaced between pulleys 8,9 of the cam shafts 1,2 at the zone A of the driving element 7, and the other roller 12 is displaced at the loaded zone B of the driving element 7 between the pulley 9 of the cam shaft 2 and crankshaft 10. To the unloaded zone of the driving element 7 uncontrolled torsion roller 13 acts. The control unit 14 through the actuating mechanisms 15 and 16, e.g. hydro-cylinders, acts to the rollers 11 and 12.
[0024] The mechanism operates by the following way. During the starting up of the engine and the idling the cams of both cam shafts 1,2 simultaneously begin and finish to act to the inlet valves 3,4 as well the outlet valves 5,6, providing by this the shortest inlet and outlet phase duration. By this the roller 11 is at the state corresponding to the smallest caving of the driving element 7 at the zone A, and the roller 12 provides a sufficient caving of the part B of the driving element 7. At increasing of the rotation frequency the control unit 14 through the actuating mechanism 15 moves the roller 11 upwards enlarging by this the caving of the part A of the driving element 7, and through the actuating mechanism 16 moves the roller 12 to the right decreasing by this the caving of the part B of the driving element 7, providing an angular shift of the cam shafts 1,2 in relation to the crankshaft 10 owing by the change of the length of the parts A and B of the driving element 7, the cam shaft 1 rotating in the direction of its rotation, and the cam shaft 2 against the direction of its rotation. Thus inlet and outlet valves 3 and 5 respectively controlled by the cam shaft 1 will open earlier and close earlier, and valves 4 and 6 controlled by the cam shaft 2 to open later and to close later, by this enlarging the total inlet and outlet phase duration by value of the total angular shift of the shafts.
[0025] By this the values of the displacement of the rollers 11 and 12 should provide lengthening of the part A of the driving element 7 by the value grater than diminution of the length of the part B, because of, e.g. in case of equality of these values, the cam shaft 1 will not have an angular shift since the total length of the loaded part B of the driving element 7 between this cam shaft 2 and the crankshaft 10 and one of the part A don't change. If the roller 12 will be remain at the initial state, the cam shaft 2 don't receive an angular shift, and the lengthening of the part A of the driving element 7 carries out owing only by the shortening of its unloaded zone, what results in the moving of the uncontrolled torsion roller 13 to the left.
[0026] For providing of the device regulation in the process of the exploitation in connection with the lengthening of the driving element 7 it is necessary to provide a sufficient initial caving of the part A in the unoperating state of the engine.
[0027] Fig.3 shows diagrams 17, 18, 19 of the dependence of the run of the inlet valves 3 and 4 from the turning angle of the crankshaft 10.
[0028] The diagram 17 shows phases of action of the inlet valves 3 and 4 at the minimum rotation frequency of the crankshaft 10. (The profiles of the cams of the cam shafts 1,2 controlling the same name valves 3 and 4 are allowed to be identical). The diagram 18 shows phases of action of the inlet valve 3 at the maximum rotation frequency. The diagram 19 shows phases of action of the inlet valve 4 at the maximum rotation frequency.
[0029] In the diagrams it may be seen that at the maximum rotation frequency the inlet phase duration reaches the value what exeeds the initial inlet phase duration , which is defined by the profile of the controlling cams, by the value which is added from an angle of the maximum shift in the outstripping direction of the inlet valve 3 phase and from an angle of the maximum shift in the lagging direction of the inlet valve 4.
[0030] For improvement of the economy of the carburettor engines it is expedient to supply the mixture through only one of the inlet valves.
Thus the proposed method of gas distribution with phase regulation and the mechanism for realization thereof provide the regulation of the inlet and outlet phase duration in the four-stroke engine with the multi-valves head in the all working range of the rotation frequency with high reliability and longevity.
Industrial applicability
[0031] The proposed method of gas distribution with phase regulation and the mechanism for realization thereof can be used in any four-stroke internal-combustion engines which operate in the large range of the rotation frequencies and need high power-economical and dynamic characteristics, e.g. in the vehicle engines.
1. A method of gas distribution in a four-stroke internal-combustion engine with phase
regulation, consisting of rotation of the cam shafts (1,2), with possibility of their
angular shift in relation to the crank shaft (10) depending on speed coorking conditions
of the engine, characterised in that the angular shift one from the cam shafts (1)
are implementing in direction of its rotation and other cam shaft (2) - against the
direction of its rotation.
2. A mechanism for gas distribution in a four-stroke internal-combustion engine with
phase regulation according to Claim 1, comprising two cam shafts (1,2), controlling
the inlet (3,4) and outlet (5,6) walves by means of cfms and device for angular shifting
of the cam shafts (1,2) in relation to the crank shaft (10), which connected with
cam shafts (1,2) through a driving-element (7), characterised in that the device for
implementation of angular shifting of cam shafts (1,2) connected with both cam shafts
(1,2) and ensure shift one from the cam shaft (1) in direction of its rotation, and
at her cam shaft (2) - against the direction of its rotation.
3. A mechanism accoding to Claim 2, characterised in that device for angular shifting
make in form two actuating mechanisms (15,16), interconnected through a control unit
(14), and provided with rollers (11,12), contacting with driving-element (7), connected
crank shaft (10) with cam shafts (1,2), one from the rollers (12) contacting with
the driving-elements (7) at the loaded zone, connected crank shaft (10) with one from
cam shaft (2), and other roller (11) contacts with the driving-element (7) at the
zone between cam shafts (1,2).