JP3121011B2 - Recovery type engine valve system and method of operating the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates generally to a method of operating a hydraulically actuated valve, and more particularly, to hydraulically actuated valves by restoring some of the energy used to pressurize hydraulic fluid. It relates to a method of operation that significantly reduces the energy consumption normally associated with valves.

PRIOR ART Hydraulically actuated engine valves are faster than mechanically actuated engine valves because they can quickly respond to changes in the operating state of the engine to change the timing of the opening and closing events of the engine valve, and thus optimally time. Is also effective.

One disadvantage commonly associated with this hydraulic system is that the amount of hydraulic energy required to quickly operate the engine valve is large. This high energy consumption
This is particularly evident when the engine valve is an exhaust poppet valve which must be opened against the relatively high gas pressures generated in the combustion chamber of the engine during the compression and combustion phases. This power consumption is 75% higher than the power required to operate a typical mechanical engine valve.

The present invention makes the energy requirements of a liquid valve system comparable to a mechanical valve system by restoring some of the energy used to pressurize the hydraulic fluid.

SUMMARY OF THE INVENTION In one aspect of the invention, an energy recovery valve system is provided that includes a valve, a low pressure fluid source, a high pressure fluid source, and optional fluid flow means.
The valve is displaceable between a closed position and an open position and has a plunger surface. The selective fluid communication means is provided for selectively communicating fluid between the plunger surface and either the low pressure fluid source or the high pressure fluid source. The plunger surface acts to urge the valve toward its open position when in communication with the high pressure fluid, and to return the pressurized fluid to the high pressure fluid source when the valve moves from its open position to the closed position. To restore some of the energy used to initially pressurize the fluid.

In another aspect of the invention, a method is provided for operating a liquid actuated valve system. The method includes communicating fluid from a low pressure fluid source to a plunger surface of the valve during a first portion of the valve displacement from an open position of the valve to a closed position, and a second portion of the valve displacement from the open position of the valve to the closed position. Providing fluid communication from the high pressure fluid source to the plunger surface in the portion.

The present invention reduces the consumption of hydraulic actuation forces typically associated with hydraulic actuation valve systems by recovering a portion of the energy used to pressurize the liquid fluid. Further, by controlling the speed of the valve while the valve is open,
When fully opened, it is possible not to overshoot the equilibrium position. Further, the speed of the valve can be controlled while the valve is closed so that the valve gently hits its seat. Further, the present invention allows the valves to be opened and closed at the most appropriate times to help optimize engine performance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic partial sectional view of an electrohydraulic valve system of the present invention.

FIG. 2 is three graphs illustrating exemplary operation of the system of FIG. 1, with the bottom graph showing microprocessor logic pulses as a function of voltage "V" versus time "t";
The middle graph shows spool valve displacement "d _SV " as a function of time "t", and the top graph shows engine valve displacement "d _eV " as a function of time "t". .

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of an engine valve system 10 of the present invention for an internal combustion engine.

The system 10 includes a first closed position (shown) and a second closed position.
One or more engine valves 12, each of which can be displaced between an open position (not shown) of the engine, and integrally formed with or individually disposed near each of the engine valves 12 A plunger 1 having a plunger surface 16; first means for biasing each engine valve 12 toward its first position, preferably a pair of helical compression springs 18; A second means for selectively communicating fluid between one of the low pressure fluid source 20 or the high pressure fluid source 22 and the plunger surface 16 through a rail 25, a source 20 of fluid, a source 22 of relatively high pressure fluid, and a rail 25. , Preferably a second valve, and more preferably a two-way spool valve 24. The spool valve 24 is biased by a helical compression spring 26 to a first position (not shown) and is moved by an actuator against a force of the spring 26 to a second position (not shown) to the right of the first position. Be moved. In this embodiment, the actuator is a piezoelectric motor 28. Adjacent to this piezoelectric motor, a piston 30 having a relatively large diameter,
There is a spring bias array, which is in hydraulic communication with a relatively small diameter piston 28 adjacent the spool valve 24. Large piston 30 and small piston
32 are spring biased away from each other.

The engine valve 12 is only partially shown in FIG. 1 and is, for example, a set of conventional exhaust or intake poppet valves arranged to reciprocate within a cylinder head 34.

Plunger 16 is guided to reciprocate within bore 36 of valve body 38.

Fluid pressure of the fluid from the low pressure fluid source 20 is preferably less than about 28kg / cm ² (400psi), more preferably, from about
Less than 14kg / cm ² (200psi). It is recommended that the low pressure fluid source be maintained at a sufficient pressure so that there is little cavitation of the rail 25 and plunger surface 16 when switching from high pressure fluid to low pressure fluid as described below.

Fluid pressure of the fluid from the high pressure fluid source 22 is preferably greater than about 105.5kg / cm ² (1500psi), more preferably, greater than about 210.9kg / cm ² (3000psi).

To clarify the industrial applicability description, the following sequence, the engine valve 12 is in the most its first position as shown by A ₁ in the graph above, i.e. its closed Azumi position of FIG. 2 and the spool It is assumed that the valve starts in its first position, as indicated by P _L in the middle graph of FIG. To start the sequence of opening the valve, the time t _1, the voltage V _H is fed to the piezoelectric motor 28. To drive a large piston 30 piezoelectric motor 28 extends, which drives the small piston 32 by the liquid pressure communication passage, then, drives the spool valve 24 from its first position P _L to its second position P _H.

Its second position spool valve 24 from its first position P _L
When moved to the P _H, the communication between the low pressure source 20 and the plunger surface 16 is closed, the communication between the high pressure source 22 and the plunger surface 16 is opened. The high pressure fluid is large enough to open engine valve 12 against the force of compression spring 18. Communication between the high pressure source 22 and the plunger surface 16, during the first part of the Ai of the displacement of the engine valve 12 to the A _2, sufficient moment to the engine valve 12 is advanced to the fully open state is accumulated in the valve Is maintained until.

In the engine valve displacement A ₂ corresponding to the time t _2,
Voltage is removed from the piezoelectric motor 28 and the spool valve 24
Is returned from its second position P _H under the force of the spring 26 to the first position P _L, and cuts off the communication between the high pressure fluid and the plunger surface 16 and again communicating the low pressure fluid with the plunger surface 16 .

From the displacement A _2, moments of engine valve 12 can be brought to it to complete the open position A _3. The progressively larger volume of rail 25 created by plunger 14 that moves downward with engine valve 12 is filled with low pressure fluid instead of high pressure fluid, thereby retaining liquid energy during the travel cycle. Thus, the hydraulic power required to open engine valve 12 can be reduced by about 10 to 20%, depending on cylinder pressure and other factors. Analysis of the A ₁ to A _3, the potential energy of the high pressure fluid is converted into kinetic energy of the engine valve 12 to motion and potential energy of the compression spring 18.

At the maximum displacement A ₃ (fully open) of the engine valve,
The kinetic energy of the engine valve 12 is reduced by the compression spring 18
Is converted to potential energy stored in The desired maximum displacement is reached when the hydraulic pressure and the force of the compression spring 18 are in equilibrium or when the plunger 14 contacts a physical stop. Without the plunger stopper, if the fluid supply does not switch to low pressure before full opening, the engine valve 12 will overshoot its equilibrium position due to its increased momentum, and the spring 18
And may cause the engine valve 12 to vibrate. Even if there is a stopper, if the plunger 14 hits the stopper at full speed, wear, destruction and vibration will be caused.

At time t ₃ when corresponding to A ₃ of the engine valve 12, the piezoelectric motor 28 is energized again, the spool valve 24 again pushes to its second position P _H, the high pressure fluid in communication with the plunger surface 16 from low pressure Switch. In this way, the engine valve 12 can maintain the open position against the force of the compression spring 18. Between t ₃ and t _4, the speed of the engine valve is zero. Engine valve 12 is thus held in the open position to the appropriate time t ₄ during the engine cycle, then closed.

At time t _4, switch from the piezoelectric motor 28 a voltage is removed, the spool valve 24 allowed to return from its second position P _H to the first position P _L, to the low pressure fluid in communication with the plunger surface 16 from high pressure This allows the engine valve
12 can start its closing stroke. At this stage, the potential energy of the compression spring 18 is converted to the kinetic energy of the moving engine valve 12.

The low pressure fluid source 20 is maintained in communication with the plunger surface 16 until a sufficient moment to close the engine valve 12 against the relatively high pressure fluid.

In the engine valve displacement A ₅ corresponding to the time t _5,
The piezoelectric motor 28 is energized again to move the spool valve 24 from its first position P _L to its second position P _H, thereby,
The fluid in communication with the plunger surface 16 is switched from low pressure to high pressure. Since sufficient moment to bring the engine valve 12 to the position A ₆ thereof closed against the force of the high pressure fluid is in the engine valve 12, now the plunger 14 is pressurized when moving from the valve A ₅ to A ₆ High pressure source 22 for pressurized fluid
It works like a fluid pump by returning it to This is the hydraulic energy recovery part of the cycle. Analytically, the kinetic energy of the engine valve 12 is converted to the potential energy of the high pressure fluid source 22. During this phase, about 30% to 50% of the hydraulic energy normally used to open engine valve 12 can be recovered. This recovery is not 100% due to the pressure drop between the spool valves 24 and the friction losses in the system. Of course, the A _6, since the engine valve 12 is reveled again, the speed of the engine valve 12 is zero.

As soon as the valve has settled down, the piezoelectric motor 28 is deenergized,
Spool valve 24 is the first from its second position P _H 1 position P _L
And the fluid in communication with the plunger surface 16 switches from high pressure to low pressure, and the engine valve 12 begins to open again. You are now ready to repeat the cycle.

The disclosed system may be designed so that the engine valve 12 is biased toward its open position and the high pressure fluid is used to push the engine valve 12 toward its closed position in an inverted configuration. You can also.

The recuperative valve system of the present invention has a number of advantages. First, the system selectively switches "on" or "off" fluid communication between the high pressure source 22 and the plunger surface 16 based on the position of the engine valve 12 to reduce hydraulic power consumption. The amount can be minimized. Second
Additionally, the displacement of the engine valve 12 in the opening direction can be controlled so that the engine valve 12 does not overshoot its equilibrium position when fully open. Third
In addition, the displacement of the engine valve 12 in the opening direction can be controlled to minimize the valve dwelling speed. 4th
In addition, the system can open and close the engine valve 12 at the most appropriate time to help optimize engine performance. Fifth, hydraulic energy can be saved and recovered during the advancement phase of the engine valve 12 to reduce the energy requirements of the system.

While the present invention has been illustrated and described as being used for a poppet engine valve 12 in an engine combustion chamber, it should be understood that the present invention can be applied to any hydraulically actuated valve that can benefit from its effects. I want to be understood.

Other objects, features, and advantages of the present invention have been described above,
It will be apparent from the accompanying drawings and the appended claims.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 9/02

Claims (8)

(57) [Claims] A valve (12) having a plunger surface (16) and displaceable between a first position and a second position.
And a first means (18) for biasing the valve toward the first position, a high pressure source (22), and a valve system (10) comprising a low pressure source (20). A single valve for displacing the communication between the plunger surface (16) and the high pressure source (22) and low pressure source (20) from the second position to the first position In the first part during this displacement, the high pressure source (22) does not communicate with the plunger surface (16) and the low pressure source (20)
Communicating with the plunger surface (16) so that the first means (18) pushes the valve (12) towards the first position, comprising:
The valve (1) moving from the second position to the first position
In the second part of the displacement of 2), before the valve (12) reaches the first position, the plunger surface (16) disconnects from the low pressure source (20) and the high pressure source (22) Is communicated with the plunger surface (16), and the momentum of the valve (12) moves the valve (12) toward the first position, so that the high-pressure fluid communicating with the plunger surface (16) is A method characterized in that the fluid source (22) is pushed back. 2. The method of claim 1, wherein when the valve (12) is in the first position, before or after communicating the high pressure source (22) with the plunger surface (16), Temporarily maintaining communication between the high pressure source (22) and the plunger surface (16) during a first portion of displacement of the valve (12) from the first position to the second position; Communication between the high pressure source (22) and the plunger surface (16) before reaching the second position in a second part of the displacement of the valve (12) from the first position toward the second position. And then continuing movement of said valve to said second position. 3. The method according to claim 2, wherein said high pressure source (22) is again in communication with said plunger surface (16) when said valve (12) reaches said second position. A method wherein the communication between the high pressure source (22) and the plunger surface (16) is broken when the valve (12) is returned to the first position. 4. The method according to claim 2, wherein the high-pressure source (22) and the plunger surface (1).
6), when the valve (12) is displaced from the first position to the second position, the plunger surface (16) is displaced by the low pressure source (20).
A method characterized by being communicated with 5. A valve (12) having a plunger surface (16) and being displaceable between a first position and a second position.
First means (18) for biasing the valve toward the first position, a high pressure source (22), a low pressure source (20), the plunger surface (16) and the high pressure source (22). ) And a single valve for controlling communication between the low pressure source (20) and means for displacing the valve (12) from the second position toward the first position, wherein the displacing means comprises: In the first part of this displacement, the high pressure source (22) is not in communication with the plunger surface (16) and the low pressure source (20) is not connected to the plunger surface (16).
A valve system (10) in which said first means (18) pushes said valve (12) towards said first position by communicating with said first means (18) from said second position toward said first position. Disconnecting said plunger surface (16) from said low pressure source (20) before said valve (12) reaches said first position during a second part of the displacement of the valve (12);
The high pressure source (22) communicates with the plunger surface (16) and the momentum of the valve (12) is
Is moved toward the first position, and the high-pressure fluid communicating with the plunger surface (16) is transferred to the high-pressure fluid source (2).
A valve system (10) characterized in that a means for pushing back to (2) is provided. 6. A valve system according to claim 5, wherein said high pressure source (22) communicates with said plunger surface (16) when said valve (12) is in said first position; Temporarily maintaining communication between the high pressure source (22) and the plunger surface (16) during a first portion of displacement of the valve (12) from the first position to the second position; The second part of the displacement of the valve (12) from the first position to the second position
Means for breaking communication between said high pressure source (22) and said plunger surface (16) prior to reaching said position, and then continuing movement of said valve to said second position. Characteristic valve system. 7. The valve system according to claim 6, wherein said high pressure source (22) communicates with said plunger surface (16) when said valve (12) reaches said second position. Means for interrupting communication between said high pressure source (22) and said plunger surface (16) when (12) is returned to said first position. 8. The valve system according to claim 6, wherein the valve (12) is turned off when communication between the high pressure source (22) and the plunger surface (16) is broken. The plunger surface (16) during the displacement of the plunger surface (16) from the first position to the second position.
Means for communicating with the valve system.