Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/352—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using bevel or epicyclic gear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic

Definitions

• the present invention is directed to a device for controlling and varying the valve timing of an internal combustion engine. More specifically, the invention is directed to hydraulic valve actuators for opening and closing the intake and exhaust valves of the engine and hydraulic actuator pumps for supplying precisely timed pulses of fluid to the actuators, the periodic action of the actuator pumps being varied by advancing or retarding a planetary gear assembly in relation to the revolution of a rotating shaft turned by the engine.
• Figure 1 is a schematic representative of a cut-away, single cylinder engine showing the actuator pump assembly and valve actuators of the invention.
• Figures 2 is a cut-away view of the actuator pump and a planet gear ⁇ assembly.
• Figure 3 is a cut-away of actuator pump.
• Figures 4a-d are cut-away views of the actuator valve illustrating the four-stage operation of the valve.
• a device for controlling the timing of the intake and exhaust valves of an internal combustion engine.
• the present invention comprises separate valve actuator means for opening and closing each of the intake and exhaust valves of an internal combustion engine and a pair of actuator pump means connected to each valve actuator means for supplying precisely timed pulses of pressurized fluid' to the valve actuator means to open and close each of the valves.
• Each actuator pump means comprises a piston disposed in a cylinder and mounted to periodically engage one or more cam lobes on a planet gear assembly which engages a rotating shaft turned by the engine. The piston of each pump is therefore depressed in a specifically controlled sequence which is related to the speed of the engine itself.
• the cam lobes are mounted on a planet gear carrier disposed concentrically about a rotating shaft which is turned by the engine.
• Planet gears are mounted on the gear carrier and engage a sun gear which is mounted on and turned by the rotating shaft.
• the planet gears are also engaged by the inner porton of a ring gear which is disposed concentrically and outside of the sun gear.
• the ring gear is turned on command by a small servo-motor which engages it on its outer periphery. Rotation of the ring gear thus causes the position of the cam lobe mounted on" the planet gear to be advanced or retarded relative to the piston of the actuator pump thereby also altering the intervals at which the piston is depressed to provide sequential pulses of pressurized fluid relative to the rotation of the rotating shaft.
• the valve actuator for opening and closing the intake and exhaust valves in response to the pulses of pressurized fluid which are received from the actuator pump essentially consists of a cylinder with first and second pistons slidably disposed end to end within the cylinder. The ends of the two pistons are connected by a compression spring.
• a valve stem terminating in a valve of the engine is connected to the end of the second piston and projects from the lower end of the cylinder.
• the upper end of the cylinder is connected to receive fluid pulses from one actuator pump in such a way that the pulse of pressurized fluid displaces the piston downward.
• the lower end of the cyliner is also connected to receive separate fluid pulses from an additional actuator pump so as to close the engine valve by displacing the second piston in the cylinder upward.
• the upper end of the cylinder is also provided with a fluid conduit means leading to a sump and the lower end of the cylinder is provided with a similar fluid conduit means leading to the same sump.
• Each of the fluid conduits leading to the sump are provided with separate unique valve means for controlling the flow of fluid between the cylinder and the sump which thereby permits the return of the pistons to their former position.
• These unique valve means are integral to the cylinder and the two pistons mounted therein. Their operation during the sequence of events comprising a full cycle of the engine valve operation will be discussed in detail below with reference to the drawings. Essentially, two pairs of entry and exit ports are provided in the side of the cylinder.
• One pair of ports is disposed radially essentially along the mid-point of the upper piston's movement in the cylinder and connected into the fluid conduit leading from the bottom of the cylinder to the oil sump while the other pair of ports is disposed radially along the mid-point of the lower cylinder's path of movement, and connected into the fluid conduit leading from the top of the cylinder to the oil sump.
• Each of the pistons disposed within the cylinder is provided with a radially constricted portion which permits a flow of fluid around the cylinder when the constriction is in alignment with the pairs of ports provided radially in the side of the cylinder.
• the respective pistons serve as valves to control the flow of fluid through the conduits leading to the sump, by either blocking or allowing the fluid to flow between the entry and exit ports.
• the entire device of the present invention including the planetary gears, actuator pump mechanism and valve actuator permits variation of the valve timing in an internal combustion engine either as controlled by the operator or by control of a • programmed solid state device such as a computer.
• the events of opening and closing of intake and exhaust valves can be varied infinitely to occur anywhere on the 720° rotation of the crank shaft or, in other words, at any point of travel between top dead center and bottom dead center of the piston on any stroke.
• the valves may be operated in either two stroke or four stroke modes. By virtue of variable valve timing the engine can operate even as an air compressor or air motor.
• valve actuator pump receives its supply of fluid such as oil maintained under a constant pressure.
• the primary source of constant pressure may preferably be the engine's lubrication pump which supplies a constant pressure of oil.
• the actuator pump in response to displacement of the pump plunger by a cam lobe, displaced a precisely timed pulse of high pressure fluid.
• Circumferential rotation or retarding or advancing of the actuator pump with respect to the cam will correspondingly retard or advance the timing of the high pressure signal.
• the cam shaft is advanced or retarded in rotation while the pump remains stationary the timing of the high pressure pulse to the valve actuator is also retarded or advanced.
• a planetary gear system is utilized as described above.
• the engine crank shaft drives the sun gear preferably at a 1:1 ratio.
• the sun gear is properly geared and drives the plant gears so that the outer edge of th planet carrier rotates 2:1 in relation to the crank shaft.
• the outer edge of the planet carrier has at least one lobe which every 360°
• OMPI depresses the plunger of the actuator pump.
• the engine When only this lobe is operating to depress the plunger of the actuator pump, the engine operates in a four stroke mode.
• a second cam lobe may, however, be provided on the outer edge of the planet carrier 180° from the first cam lobe. Preferably this second cam lobe can be moved either mechanically of fcydraulically in and out of the path of the actuator pump plunger. When in the path of the plunger the engine will operate in a two stroke mode.
• Two actuator pump assemblies are required for each valve. One assembly opens and the other closes the valve. In the event of multiple cylinder engines all intake actuator pumps are mounted circumferentially on one assembly with the same number of degrees between respective intake pumps as the number of crank shaft degrees differs between respective cylinders.
• the hydraulic valve train system of the present invention can be infinitely varied in timing or valve events. This permits the operator to tailor the torque or output/rpm of an engine to meet any load or performance requirement from maximum torque at low rpm, as required .for example by a truck or tractor engine, to maximum torque at high rpm as required by high performance race cars. Conversely, the fuel economies and pollution emission characteristics of the engine can be enhanced because the engines performance can be optimized at all times. All of these engine outputs can be changed while the engine is in operation. Further, because the torque/rpm can be tailored with variable valve timing, relatively flat torque/rpm curves can be obtained as compared with an engine with static cam or limited variabler valve timing device having a bell shaped torque/rpm be used.
• FIG. 1 a schematic cross section of a single cylinder internal combustion engine is shown in which an engine block 1 is provided with a cylinder 2 having a piston 3 mounted therein. Oil sump 4 is provided with oil return line 16 and 15b leading from the sump to oil pump 48. Line 15b is further directed into fluid
• actuator valve 10a is provided with a hydraulic valve actuator 10a while intake valve 6 is provided with a similar valve actuator 10b.
• Each of the actuator pumps 10a and 10b are provided with two fluid conduit lines each of which in -turn leads to its own actuator pump activated by a separate planet .Carrier lobe.
• actuator valve 10a possesses the same structure and function.
• Fluid conduit 8 leads to valve actuator 10a to provide the "open" valve signal recieved from actuator pump 14 which is mounted in the pump mechanism 11 to be periodically depressed by cam lobe 19.
• conduit 9 leads to another actuator pump mechanism mounted also within mechanism 11 so that the valve actuator received a "close” valve signal in proper sequence. Details of the construction and operaion of the mechanism by which the cam lobe is turned by the shaft 5 to depress the piston or plunger in the actuator pump will be more fully described with reference to Figure 2 of the drawings.
• the interval at which the cam engages the plunger on the actuator pump is, however, controlled by a small motor (not shown) having a gear 13 which engages the large ring gear 22. This small control motor 13 is connected to the fluid control unit 12.
• the actuator pump within mechanism 11 is provided with actuator pump 14 having piston 21 slidably disposed therein.
• rotating shaft 5 Within the mechanism 11 is rotating shaft 5, which is turned at a 1:1 ratio by the internal combustion engine itself.
• planet gear carrier 20 Disposed concentrically about the rotating shaft 5 is planet gear carrier 20 on which are mounted cam lobes 19 and 24.
• Planet gears 23 are also mounted on the planet gear carrier and engage a sun gear 29 mounted on and turned by the rotating shaft 5.
• the planet gears 23 also engage the inner portion of a ring gear 22 disposed outside of the sun gear 29.
• the ring- gear 22 On its outer periphery the ring- gear 22 engages a gear 13 which is driven by a motor controlled by the fluid control device 12.
• the relative interval therefore at which the cam lobes 19 and 24 engage the piston 21 to provide an impulse of high pressure fluid to the line 25 in relation to the turning of rotating shaft 5 is controlled by turning with gear 13 the ring gear 22 engaging the multiple sun gears 23.
• piston 21 disposed within the actuator pump body 14 is piston 21 which projects downward to engage the cam lobes 19 mounted on gear carrier 20. Engagement of the lower end of the piston 21 with the cam lobe 19 is maintained by spring 26. Constant low pressure fluid, such as oil, is provided to the upper interior portion of the cylinder 14 through line 28 which is provided with a check valve 28a for preventing return flow of the pressurized fluid through that line. As the gear carrier 20 turns and brings the cam lobe 19 into engagement with the bottom of the piston 21, the piston is depressed upward in the cylinder 14 to cause a surge of high pressure fluid above the piston to be injected into the line 25. Valve 27 prevents return flow of the pressurized surge of fluid from the line 25 into the cylinder.
• a mechanism which may be hydraulic as shown or mechanical is provided to move the cam lobe out of the path of the piston 21.
• this provision can consist of a hydraulic line 18a provided with a suitable piston for moving the. cam lobe 19 laterally with a return spring 18b for returning the cam lobe to position once the hydraulic pressure in line 18a is terminated. It will be apparent that other mechanical means for moving the cam lobe may be practiced within the scope of the present invention.
• the valve actuator device of the invention consists of a cylinder 30 having disposed therein pistons 31 and 32 connected by compression spring 34.
• the lower piston 32 is connected by valve stem 33 to valve 45.
• a fluid conduit 35 is connected to one actuator pump which provides the time pulse of pressurized fluid from one actuator pump to open the valve 45.
• a second conduit 36 is connected to a second actuator pump for receiving a time pulse of pressurized fluid and to cause closing of the valve 45.
• Fluid conduit 39 directs pressurized fluid through valve means to conduit 40 and thence to sump 4.
• a similar fluid conduit 37 directs pressurized fluid from the bottom of the cylinder 30 through valve means to conduit 38 and then to sump 4.
• stage one ( Figure 4a) a pulse of pressurized fluid is received from the actuator pump through line 35 into the top 46 of the cylinder 30 causing the piston 31 to be pressed downward thereby compressing spring 35 then contacting lower piston 32, and forcing the lower piston 32 downward to open the valve 45.
• the radial constricted portions 43 and 41 of the respective cylinders 31 and 32 are ech respectively directly opposed to the pairs of entry and exit ports -44 a, b, and 42 a, b thereby permitting the flow of hydraulic fluid through the pairs of lines 39-40 and 37-38.
• stage 2 Figure 4b
• the pulse of pressurized fluid through line 35 has ceased and the compression spring 34 forces the cylinder 31 back upward against the top of the cylinder 30.
• the radial constriction 43 in the piston 31 is now no longer opposed to the ports 44 so taht the conduit 37-38 is closed to the flow of fluid.
• valve 45 is still open, it is now hydraulically free to move upward, if force is applied upward, for example, accidentally.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)

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• 1984
  • 1984-10-15 EP EP84903864A patent/EP0197033A1/de not_active Withdrawn
  • 1984-10-15 WO PCT/US1984/001651 patent/WO1986002405A1/en unknown

Non-Patent Citations (1)

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