WO2001096715A1

WO2001096715A1 - Hydraulic valve actuating gear of an internal combustion engine

Info

Publication number: WO2001096715A1
Application number: PCT/HU2001/000067
Authority: WO
Inventors: Attila PÜSKI
Original assignee: Pueski Attila
Priority date: 2000-06-13
Filing date: 2001-06-11
Publication date: 2001-12-20
Also published as: AU2001269345A1; HU0002260D0; HUP0002260A2; HU221875B1

Abstract

A valve actuating gear (1) for an internal combustion engine, wherein a valve lifting block or a balancing lever (22) is connected to the valve stem (21), and a control element (8) is connected to the said elements in valve actuating arrangement. The characteristic feature of the device according to present invention is that the control element (8) having a lower part shaped as a piston with sloped control Edge (82), which moves in a hydraulic cylinder (30) with a side opening (31), is provided with a gear rim (15), to which a linearly moving gear rack (11) controlled by a servo-motor (12) is connected.

Description

HYDRAULIC VALVE ACTUATING GEAR OF AN INTERNAL COMBUSTION ENGINE

The field of the invention A valve actuating gear for an internal combustion engine, consisting of a valve lifting block or a balancing lever connected to the valve stem and a control element connected to it in an arrangement actuating the valve.

The Prior Art The operation of advanced motor-cars is supported by usage of high-level technology, internal control apparatuses and usage of feedback, e. g. in the solution described in the U. S. patent specification 5,957,097. The economic and effective run of the engine requires, that the engine should always develop the required power at different loads and speeds, it should consume the least possible combustible and emit the least possible contaminating agents. A such solution is disclosed in the U. S. patent specification 5,881,690. The engine manufacturing companies endeavour to lead the actually necessary quantity of combustible at any moment, to ensure the perfect combustion, and to initiate the combustion at the optimal position of the piston (see U. S. patent specification 5,904,124) One of the most important conditions is, to fulfil these tasks, to actuate properly the valves, i. e. to open and close them at the proper moment and with the required width. Consequently, it is required for the optimal operation, to control adequately the valves. The perfect combustion can be performed only at a complete accordance of functioning, of all the parts of engine. One of conditions thereof is to open the valves at the right moment of time and to hold them open for the required time and only for this time. A smaller quantity of combustible is enough at a low speed but it should be burned perfectly. A small valve opening is desirable for this purpose, to establish the necessary turbulence in the cylinder. A large valve opening is necessary at a high speed, to let the required higher quantity of combustible in. It is extensively known, that the car factory HONDA applies a construction with relatively short stroke length a great diameter of cylinder and large valves. It uses an actually generally used construction with two inlet and two exhaust valves perforation cylinder, and opens only one of valves at low speed and both valves at high speed. This solution does not provide a continuously adaptable valve opening. According to another solution, the valves are actuated by a hydraulically controlled piston, the actuating pressure thereof is provided by another piston, controlled by the camshaft. The width of opening can be regulated by means of reduction of pressure, which can be done by an electrohydraulic valve. A continuous regulation can be provided by this solution. The adaptation to the speed is ensured by turning of camshaft around its axis to a defined angle. Another well-known method to influence the operation of engine is a partial overlapping of intake and exhaust periods, used at high speed. It makes the intake more intensive using the suction effect of the outflow of exhaust gases. This method is disadvantageous at low speed it is used only by high speed using the change of timing angle of the camshaft. There are several well-known variants of this method. The company ALF A-ROMEO applies the change of angle only on intake camshaft in two stages in its engines, the TOYOTA applies the same solution but with continuous adaptation, the BMW changes the angles of both intake camshaft and that of the exhaust one.

The known solutions do not provide proper adaptation to the running conditions of the car and to operating parameters of the engine. Furthermore, they add more components and apparatuses to the sophisticated mechanism, which is characteristic to the modern cars. It increases the price of car, increases the intensity of failures and makes the repair more difficult.

The field of invention The aim of present invention is to develop a valve control, which is based on the existmg internal control and data supplied by the sensors of parameters, eliminates disadvantages of former solutions and regulates the time, time space and width of valve opening i. e. all the three parameters in accordance with each other within one apparatus. The disclosure

The recognition underlying the invention is, that the known arrangements of engines can be substantially simplified by omitting the one or two camshafts, and all the three essential parameters of the valve opening: the time of opening, the time space of being open and the flow area can be controlled simply with a single device.

According to the inventive recognition, a piston in a cylinder with a side opening can be moved, of course, only up to the said side opening, which determines the height of lifting i. e. the hight of opening of the valve. If the bottom surface of the piston is provided with a profile, so that it reaches the side opening at the end of movement of different length, in accordance with its turning to different angles around its axis, a continuous regulation of the lifting height of the valve is obtained. The recognition underlying the invention is, that the hydraulic regulation applied in the apparatus defining the lifting height of the valve enables to regulate the time of opening and the time space of the open state of the valve with adaptation to the actual operation of engine, and makes this regulation very simple at he same time, as well. This recognition means, that all the three parameters necessary for the optimal operation of cylinder valves can be regulated by a single apparatus. According to the above mentioned inventive recognitions, the solution accomplishing the aim is a valve actuating gear for an internal combustion engine, wherein a valve lifting block or a balancing lever is connected to the valve stem, and a control element is connected to it in an arrangement actuating the valve. The characteristic features of the valve actuating gear are that the control element has a lower part shaped as a piston with a sloping controlling edge moving in a hydraulic cylinder with a side opening, and it is provided with a geared rim, and a gear rack is connected to the rim, which moves freely controlled by a servo-motor. An advantageous feature of the valve actuating gear according to the invention is, that its hydraulic system is equipped with a high-pressure pump, driven by the crankshaft. Another advantageous feature of the valve actuating gear according to the invention is, that the intake side of pump is connected either with the engine sump, or, if necessary, with a separate servo oil tank to supply the pressure transmitting medium. A further advantageous feature of the valve actuating gear according to the invention is, that the hydraulic system consists of high-pressure parts and low- pressure ones, which are separated expediently by electronically controlled valves. Another further advantageous feature of the valve actuating gear according to the invention, that a pressure sensor is built into the low pressure part connecting to the side opening.

A further advantageous feature of the valve actuating gear according to the invention is, that the high-pressure parts and the low-pressure ones are connected with the engine sump by means of a return pipe equipped with a pressure regulating valve or a pressure maintaining one. An advantageous embodiment of the valve actuating gear according to invention can be characterised by that a central unit is in controlling connection with the pressure regulating valve.

An advantageous embodiment of the valve actuating gear according to invention can be characterised by that the high-pressure part and/or the low-pressure one are connected to several valve controllers.

Another advantageous embodiment of the valve actuating gear according to invention can also be characterised that only one of the two intake valves and respectively one of two exhaust ones of a cylinder are equipped with the apparatuses consisting of geared rim, geared rack and servomotor. The valve actuating gear according to invention can be . advantageously characterised by that a controlling output of an electronic central unit is connected to the servomotor, which unit delivers an output as function of the actual parameters, like load, speed and power, of the engine. The detailed description of the invention is presented below with references to the attached drawings, without limitation of either the applicability of the invention or the scope of protection claimed to the presented examples. Figures: Figure 1: Scheme of an advantageous embodiment of the invention.

Figure 2: Schematic drawing of the control element according to the invention.

Figure 3: Part of the valve controller according to Figure 1 containing the hydraulic cylinder.

The valve controller 1 consists of a mechanical, an electronic and a hydraulic units. The mechanical unit consists of a balancing lever 22, a control element 8, a gear rack 11 and a servo-motor 12, which are connected in the described order. The electronic unit consists of a central unit connected to the servo-motor and controlling it. The hydraulic unit consists of a high- pressure part 40 and a low- pressure part 90. The high-pressure part includes a high-pressure pump 2, a common pipe 5, a pressure storage 3, a high-pressure valve 6 and a pressure regulating valve 4. The low-pressure part 90 includes a low-pressure valve 7, a low-pressure common pipe 9, a pressure sensor 14 and a pressure maintaining valve 10. The balancing lever is a two-armed lever, with one end on the valve stem 21 of the valve 20. the other end is coupled to the control element 8. The control element 8 is a cylinder, its lower end seats into a cylinder 30 and is shaped as a piston moving in it. This piston has a sloped bottom surface and ends with a control edge 82. The cylinder 30 is provided with a side opening 31, which is connected to the low-pressure part 90 of the hydraulic unit to the low-pressure common pipe. The admitted length of movement of the control element 8 in the cylinder is determined by the greatest height of lifting of the two-arm lever 22. The side opening 31 is shaped in such height, that the control edge 82 is exactly above the lower edge of side opening at the upper end position of the control element 8. The control element 8 is surrounded with a gear rim 15 on its upper part above the hydraulic cylinder 30. The gear rack 11 of the same pitch is coupled to the said rim 15. The gear rack 11 is mounted to enable a movement perpendicular to the control element 8. A servo-motor 12 is coupled to the gear rack 1. The servomotor is electrically connected with a central unit 13. The central unit 13 is an electronic apparatus, preferably a micro-controller, which receives the parameters characterising the actual operation of the engine, like the actual angle of crankshaft, which determines the ignition, the signal of the speed of crankshaft, which determines the ignition advance, the load signal, corresponding to the position of accelerator, and the temperature signals. The central unit 13 can be programmed according to design considerations of the manufacturer, and it controls the movement of the servo-motor i. e. the movement of the gear rack in accordance with the processed input signals mentioned above. The high-pressure part 40 of the valve controller 1 is connected to the engine sump 16 through the inlet side of the high-pressure pump 2. The delivery side of the high-pressure pump enters the common pipe 5 and it is provided with an oil-pressure gauge 3. The inlet opening 32 of the hydraulic cylinder 30 and the common pipe 5 are separated by an electronic high-pressure valve 6 on one hand. The inlet opening 32 and the low- pressure part 90 are separated by a low-pressure valve 7 on the other hand. The low-pressure common pipe 9 of the low-pressure part 90 is connected to the side opening 31 with one end and to the pressure maintaining valve 10 closing the low- pressure part, with the other end. A return pipe 17 is connected to the outlet side of the pressure maintaining valve 10, which leads to the engine sump 16 and is separated from the high-pressure part by a pressure regulating valve 4. Both separating valves are preferably mechanical ones, they are adjusted by spring force, they open at excess of the pressure limit to the side of the return pipe 17, but they are always closed to the opposite side. In an advantageous embodiment of the valve controύer 1 a separate oil tank is applied instead of the engine sump 16. The valve controller 1 according to the invention can be advantageously applied in the nowadays generally used engines with several inlet and exhaust valves per cylinder so that a hydraulic cylinder 30 with a high-pressure valve 6 and a low-pressure one 7 is applied to each controlled valve, but the high-pressure part 40 and the low- pressure part 90 are common for all hydraulic cylinders i. e. for all controlled cylinder valves 20. According to one of advantageous embodiments only one of the two inlet valves 20 of a cylinder is provided with the assembly consisting of the gear rim 15, gear rack 11 and servo-motor 12. The operation of the valve controller 1 is as follows: The high-pressure pump 2 sucks oil from the engine sump 16 and delivers it into common pipe 5, so it produces continuously high pressure in the high-pressure part, its capacity is maintained by the pressure storage 3. If the pressure excesses the allowed limit, the overpressure opens the pressure regulating valve, and the excessive quantity of oil flows back to the engine sump 16. The pressure regulating valve 4 is one of the most important components of the system, because this valve ensures the required pressure in the system. It is not necessary to maintain an unchangeable pressure in the system in any case, the pressure can become higher at high speed. The system should answer namely quicker, but a lower pressure can be sufficient at low speed, the losses can be reduced in this way. At the moment that the engine valve opens, the high-pressure electronic valve 6 opens upon a command of the central unit 13, the high-pressure medium flows through the inlet opening 32 into the hydraulic cylinder 30, lifts the control element and the balancing lever therewith so it opens the cylinder valve 20. The control element 8 closes the side opening 31, but as it elevates, opens the said opening. The oil pressure diminishes in this way, and the control element 8 does not elevate any more, but it remains at the elevation, because as it goes downwards, closes the side opening 31 and the pressure is again in effect. As the electronic low-pressure valve 7 is opened, the lifting pressure ceases and the valve spring 23 closes the cylinder valve 20. The gear rack 11 is moved in one or other sense by the servo-motor 12 controlled from the central unit, as necessary, and the gear rim 15 and the control element 8 are turned around their vertical axis according to this movement. The control edge 82 turns, as well, as consequence, and it opens respectively closes the side opening at a different height of the control element 8. This way the lifting and the balanced height of the control element 8 becomes different, depending on the turn. Summarising all what was mentioned, we can say that the turn of the control element 8 by the gear rack 1 determines the height of opening of the cylinder valve 20, i. e. the height of the flow area, and the time elapsed between the opening of the high-pressure valve 6 and that of opening of the low-pressure valve 7 determines the time of the opening of the cylinder valve 20. The pressure maintaining valve 10 ensures that a minimum pressure remains in the low-pressure part 90. Air cannot enter the system in this way, and the system remains continuously operable in this way. As mostly two intake valves per cylinder are applied, it is sufficient to apply- the controllable opening only to a half of cylinder valves, because the task can be solved even in this way, and the gear rack 11, the gear rim 15 and the servo-motor can be spared at a half of intake valves. The „overlapped" opening of the valves, as it was mentioned in the introduction, can be performed simply using the valve controller 1 according to invention, as well. As follows from the description, the valve controller 1 according to invention is an apparatus applicable to regulate the moment, the duration and the flow area of the opening of a cylinder valve 20, as function of the power, speed and load of an engine. The valve controller 1 can be built into structures of known engines, it can be well attached to their existing components and it can operated in accordance with the operation of said components. The valve controller 1 according to invention accomplishes adaptation to high speed and low one alike by continuous change of the flow area, enables the „overlapped" opening of valvesand furthermore it enables the recirculation of exhaust gas in fuel -injection engines. A further advantageous feature of the valve controller 1 according to invention is that it makes the camshaft (or separated camshafts on the intake and exhaust sides) unnecessary and enables to eliminate them.

Claims

1. A valve actuating gear for an internal combustion engine, wherein a valve lifting block or a balancing lever is connected to the valve stem, a control element is connected to the said elements in valve actuating arrangement, characterised by, that the control element (8) having a lower part shaped as a piston with sloped control edge (82), which moves in a hydraulic cylinder (30) with a side opening (31), is provided with a gear rim (15), to which a linearly moving gear rack (11) controlled by a servo-motor (12) is connected.

2. The valve actuating gear according to Claim 1 characterised by, that its high- pressure system is equipped with a high-pressure pump (2) driven by the crankshaft.

3. The valve actuating gear according to the Claims 1 or 2 characterised by, that the intake side of high-pressure pump is connected with either the engine sump (16) or a separate servo oil tank.

4. The valve actuating gear according to any of Claims 1 to 3 characterised by, that the hydraulic system advantageously consists of a high-pressure part (40) and a low pressure one (90), which are separated by electronically controlled valves (6, 7).

5. The valve" actuating gear according to any of Claims 1 to 4 characterised by, that a pressure sensor (14) is included into the low-pressure part (90) connecting to the side opening (31).

6. The valve actuating gear according to any of Claims 1 to 4 characterised by, that the high-pressure part (40) and the low-pressure part (40) are connected with the engine sump (16) by a return pipe (17), which is closed by a pressure regulating valve (4) and a pressure maintaining valve (10).

7. The valve actuating gear according to the Claim 6 characterised by, that the central unit (13) is in a control connection with the pressure regulating valve (4).

8. The valve actuating gear according to any of the Claims 1 to 7 characterised by, that the high-pressure part and/or the low pressure part is connected with several valve controllers.

9. The valve actuating gear according to any of the Claims 1 to 8 characterised by, that only one of two intake valves (20) pertaining to an engine cylinder is provided with the assembly consisting of the gear rim (15) gear rack (11) and servo-motor (12).

10. The valve actuating gear according to any of the Claims 1 to 9 characterised by, that a control output of the electronic central unit (13) working in function of characteristic values of the operation of engine is connected to the servomotor.