MXPA98001035A - Internal combustion motor with combined cam and motor valve control electrohydraul - Google Patents

Abstract

The present invention relates to an internal combustion engine having a four-stroke positive energy mode and including a motor cylinder valve that opens and closes selectively, a cam having a plurality of projections synchronized with the possible openings of the motor cylinder valve, a hydraulic link containing hydraulic fluid operatively coupled between the cam and the motor cylinder valve to selectively respond to the projections causing the valve to open, and a valve operated electrically by a control circuit electronic to selectively release the hydraulic fluid from the hydraulic link to selectively modify the openings of the engine cylinder valve in response to the projections, the electrically operated valve being selectively operable to allow the motor cylinder valve to remain fully closed in response to any one of the protruding and to open in response to a second of the protrusions characterized in that the electrically operated valve opens and closes multiple times during each period (0º- 720º) of operation of the engine comparable to every four cycles (0º- 720º) of the positive energy operation of mot

Description

INTERNAL COMBUSTION MOTOR WITH COMBINED CAM AND PE CONTROL ELECTRO-HYDRAULIC MOTOR VALVE BACKGROUND OF THE INVENTION This invention relates to internal combustion engines and more particularly to internal combustion engines with valves that can be opened by cams that cooperate with hydraulic circuits that are partially controlled by electrically operated hydraulic fluid valves. In most internal combustion engines, the cylinder inlet and exhaust valves are open and closed (at least for the most part, by means of cams in the engine.) This makes it relatively difficult and impossible to adjust the regulations and / or engine valve opening amounts to optimize those openings for various engine operating conditions such as changes in engine speed.It is known to include the hydraulic ligating adjustment mechanism between a motor cam and the cylinder valve of the engine. The motor controlled by that cam makes it possible to make small, relatively small adjustments in the valve strokes in relation to the profile of the cam, (see, for example, Rembold et al, US patent 5,113,812 and Schmidt et al, 5,325,825). they can be used to provide additional valve openings when it is desired to convert the positive energy mode motor to the engine braking mode of the engine. compression release (see, for example, Cartledge U.S. patent 3,809,033 and Gobert et al, U.S patent 5,146,890). The hydraulic circuits can also be used to cause a part of the motor other than the cam that normally controls a motor valve to provide additional openings of the valve when it is desired to convert the positive energy motor to the compression release motor braking mode ( see, for example, Cummins US patent 3,220,392 and Hu US patent 5,379,737). The Schecter patent U.S. 5,225,641 shows in Figure 16 that a motor cam can be linked to a motor cylinder valve by a hydraulic circuit that includes a solenoid valve to selectively release the hydraulic fluid from the hydraulic circuit. Schecter points out that various forms of the motor cylinder valve are raised against the curve of the cam which can be obtained by the variation and duration of the voltage pulse of the solenoid. However, Schecter does not suggest that any protrusions on the cam can be completely neutralized in this way. It may not be possible to convert a positive energy mode motor to the compression release motor braking mode and vice versa without the ability to selectively and completely neutralize any projections on an engine cam. Sic ler U.S. Patent 4,572,114 shows the control of the internal combustion engine cylinder valve which essentially uses two substantially separate hydraulic circuits to control the "movement of each motor cylinder valve." One of those two hydraulic circuits controls the selective decoupling of each valve. motor cylinder from its mechanical input driven by normal cam The other hydraulic circuit provides alternative hydraulic inputs for the motor cylinder valve when the normal mechanical input is decoupled The control for those two hydraulic systems can be essentially mechanical and / or hydraulic as in Figure 5, or may be essentially electronic as shown in Figure 7. The two hydraulic circuits may have a common source of hydraulic fluid and may have other transverse connections, although they are largely separated in operation and may each require a hydraulic connection separate seal (for example, 136 and 212 in Figure 5 or 258 and 212 in Figure 7) for each cylinder valve operating mechanism. European patent application 593,908 shows an apparatus in which a mechanical link between an internal combustion engine exhaust valve cam and an associated exhaust valve boom can be reconfigured in hydraulic form. In a configuration, the mechanical link only responds to an escape projection on the cam. In another configuration the mechanical link responds to the compression release motor braking projection and a portion of the exhaust projection on the cam. However, this reference does not show a mechanical link that can completely ignore the escape projection. There is no reference to dynamically showing the selection of different portions of the compression release engine braking projection for the exhaust valve to respond to it. The U.S. patent of D'Alfonso 5,152,258 shows hydraulic links between the cams and the cylinder valves of an internal combustion engine. D'Alfonso shows that electromagnetic valves can be used to selectively release hydraulic fluid from or trap the hydraulic fluid in those hydraulic links. However, D'alfonso teaches that these electromagnetic valves are too slow for repeated opening and closing during a complete motor operation cycle (eg, the time required for four strokes of a piston in a four-stroke engine). D'Alfonso therefore teaches that multiple electromagnetic valves in parallel are required when the quickest control of a hydraulic link is necessary. D'Alfonso also does not teach anything about compression release motor braking since D 'Alfonso is related only to exhaust braking. From the foregoing it will be noted that the known hydraulic modifications of the cam control for motor cylinder valves tend to be relatively limited in extent and purpose (eg, as in Figure 16 of the Schechter patent) or require circuits relatively complex hydraulic systems (for example, as in the Sickler patent). It is therefore an object of this invention to provide an improved and simplified hydraulic circuit that can be used to extensively modify the operation of engine cylinder valves in response to engine cams. It is another object of this invention to provide relatively simple hydraulic circuits that can be selectively used to partially or completely suppress any motor valve operation associated with the motor cam that otherwise controls that motor valve, for example, to switch the motor between positive energy mode operation and compression release braking mode operation and / or to adjust the regulation of motor valve openings for various engine operating conditions.

BRIEF DESCRIPTION OF THE INVENTION These and other objects of the invention are achieved in accordance with the principles of the invention by providing a hydraulic circuit link at the connection between an engine cam and an engine valve associated with that cam. The hydraulic circuit is partially controlled by a hydraulic valve operated in electrical form (for example, to selectively release the hydraulic fluid pressure in the hydraulic circuit). The hydraulic circuit is preferably constructed so that when the electrically operated hydraulic valve releases the hydraulic fluid pressure in that circuit, there is sufficient periodic movement between the mechanical input to the circuit and the mechanical output from the circuit to prevent any selected cam function or functions are transmitted to the motor valve associated with that cam. This allows the electrically controlled hydraulic circuit to fully control which function or cam functions of the associated motor valve will respond and that cam function or functions will not respond to the motor valve. In addition, the electrically operated hydraulic circuit can modify the response of the motor valve to various cam functions (for example, to modify the regulation of engine valve responses to those cam functions) in the preferred embodiments, only necessary an individual connection of hydraulic fluid to the mechanism of each valve. Also in preferred embodiments the final entry for all openings of each motor valve comes from an individual cam associated with that valve. The additional features of the invention, its nature and various advantages will become more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified schematic diagram of a portion representative of an illustrative embodiment of an internal combustion engine constructed in accordance with the principles of this invention. Figure 2a is a simplified diagram of an illustrative signal waveform usable in the apparatus of Figure 1 or in any of the alternative embodiments shown in Figures 8-10. Figure 2b is a simplified diagram of an illustrative movement of a motor cylinder valve in the apparatus of Figure 1 or in any of the alternative embodiments shown in Figures 8-10 Figures 2c, 2e, 3a, 4a, 5a 6a, 7a, 7c, 7e and 7g are diagrams of the same general type as Figure 2a. Figures 2d, '2f, 3b, 4b, 5b, 6b, 7b, 7d, 7f, and 7h are diagrams of the same general type as Figure 2b. Figure 8 is a diagram similar to Figure 1"showing an alternative embodiment of the invention. Figure 9 is another diagram similar to Figure 1 showing another alternative embodiment of the invention. Figure 10 is still another diagram similar to Figure 1 showing still another alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES As shown in Figure 1 an illustrative embodiment of an internal combustion engine 10 constructed in accordance with this invention includes a cylinder head of the engine 20 in which the engine cylinder valves such as the valve 30 are mounted in a movable manner . As is conventional, motor cylinder valves 30 control the flow of gas to and from cylinders (not shown) of the engine. The representative valve 30 is an exhaust valve although it will be understood that the valve 30 can alternatively be an intake valve or that both the intake and exhaust valves of the engine can be controlled as described for the valve 30. The valve 30 is driven and typically towards its upper (closed) position by means of prestressed compression coil springs 32. The valve openings 30 can be produced by projections such as 42a and 42b on the rotating motor cam 40. For example, the cam 40 can rotate conventionally once for every two revolutions of the engine crankshaft (assuming that the engine is a four-stroke engine). The cam 40 can be synchronized with the engine crankshaft so that the cam projection 42a passes the master piston 60 (described below) during the exhaust stroke of the engine piston associated with the valve 30. The cam projection 42a it is therefore the projection to produce the normal exhaust stroke openings of the exhaust valve 30 during positive energy mode operation of the engine. The cam projection 42b passes the master piston 60 near the end of the compression stroke of the engine piston associated with the valve 30. The cam projection 42b can therefore be used to produce the compression release openings of the valve. exhaust 30 during braking mode operation of engine compression release. (A third possible cam projection 42c is shown in lines in transparency in Figure 1 for discussion purposes in relation to Figures 7a to 7h.) This third cam projection should be ignored until the discussion of the group in Figure 7). If the valve 30 is an intake valve instead of an exhaust valve then the projections 42 of the associated cam 40 will have different angular shapes and locations from those shown in Figure 1 although the underlying operating principles are the same. Cam 40 is selectively linked to valve 30 by hydraulic circuit 50 which will be described below. In the embodiment shown in Figure 1, the structure 52 in which the hydraulic circuit 50 is placed is fixed and stationary with respect to the head of the motor cylinder 20. For example, the structure 52 can be fastened with bolts to the head 20. The hydraulic circuit 50 includes a master piston 60 which can be hydraulically coupled to a slave piston 70. The master piston 60 receives a mechanical input from the cam 40 (in particular, the projections 42 of the cam), and if the hydraulic subcircuit 64 between the master and slave pistons is sufficiently pressurized, that inlet is hydraulically transmitted to the slave piston 70 to cause the slave piston to produce a corresponding mechanical outlet. This mechanical output of the slave piston 70 opens the valve 30. When the engine is operated the hydraulic fluid pump 80 supplies the pressurized hydraulic fluid from the lubricant manifold 78 to the subcircuit 64 by means of the valves 82 and 84. The fluid pressure The hydraulic supply supplied by the pump 80 is sufficient to push the master piston 60 out of contact with the peripheral cam surface 40 and to push the slave piston 70 out of contact with the upper end of the valve rod 30 although it is not sufficient to cause the slave piston 70 opens the valve 30. For example, the pressurized hydraulic fluid supplied by the pump 80 may be approximately 344.75 to 689.5 kPa (50 to 100 psi). Any excessive pressure produced by the pump 80 by the release valve 86 which returns the hydraulic fluid to the inlet of the pump 80. The hydraulic fluid may be the engine lubricating oil, motor fuel or any other suitable fluid. The hydraulic fluid accumulator 90 helps maintain the subcircuit 64 filled with hydraulic fluid of at least about the outlet pressure produced by the pump 80. An electrically controlled hydraulic valve 100 is provided to selectively release the hydraulic fluid pressure (prior to the outlet pressure of the pump 80) from the subcircuit 64. When the valve 100 is closed, the hydraulic fluid is trapped in the subcircuit 64. The subcircuit 64 will then hydraulically transmit a mechanical input from the cam 40 and the master piston 60 towards the slave piston 70, thereby causing the slave piston to produce a mechanical outlet that opens the valve 30. On the other handWhen the valve 100 is opened, the hydraulic fluid can escape from the subcircuit 64 to the accumulator 90. This prevents the circuit 64 from transmitting an input from the cam 40 and the master piston 60 to the slave piston 70. The valve 30 therefore does not open in response to the cam inlet. The valve 100 can preferably vent from the subcircuit 64 all the hydraulic fluid flow produced by the longer stroke of the master piston 60 resulting from any protrusion 42 on the cam 40. In this way the valve 100 can be used to cancel complete and effectively or suppressing (by means of movement lost in the subcircuit 64), any input from the cam 40. If the accumulator 90 receives too much hydraulic fluid, its piston moves further to the left to momentarily open a drain 92 back to the hydraulic fluid manifold 78. Valve 100 is controlled by electronic control circuit 110 associated with motor 10. Control circuit 110 receives various inputs 112 from the motor and vehicle instruments 114 (which may include inputs initiated by the driver of the vehicle) and produces output signals 108 to control properly 33 the valve 100 (and other similar valves in the engine 10). For example, the control circuit 110 may control the valve 100 differently depending on factors such as the speed of the engine or the vehicle, whether the engine is in the positive energy mode or the braking mode of the compression release engine. , etc. The control circuit 110 may include a microprocessor suitably programmed to execute algorithms or look-up table operations to determine the appropriate output signals 108 for the inputs 112 that the control circuit is currently receiving. The instrumentation 114 includes motor detectors (e.g., a detector at the crank angle position of the motor) to maintain basic synchronization between the motor and the control circuit 110. FIGS. 2a to 2f illustratively show the signals of control for valves such as the valve 100 and the resulting movements of the motor valves such as the valve 30 under various operating conditions of the engine. For example, Figure 2a shows the signal 108 from the control circuit 110 to control the valve 100 associated with the exhaust valves 30 of the typical engine cylinder during positive energy mode operation of the engine. (Referring to Figure 2a and other similar Figures, the associated valve 100 is closed when the signal stroke is high.) The numbers along the base line in Figure 2a are degrees of the crankshaft angle of the engine and are also applied. for all Figures, below Figure 2a). Figure 2c shows the corresponding signal 108 during the braking operation of the engine compression release motor. Figure 2e shows the signal 108 from the control circuit 110 for controlling the valve 100 associated with the intake valves 30 of the same engine cylinder with which Figures 2a and 2c are associated. In this example, Figure 2e is the same for both the positive energy mode operation and the engine compression release motor braking operation. As shown in Figures 2a and 2b, since the valve 100 associated with the hydraulic subcircuit 64 for the exhaust valve is closed when the exhaust projection 42a on the cam 40 passes the master piston 60, that projection causes the valve Exhaust 30 is opened as shown in Figure 2b during the associated engine cylinder exhaust stroke (ie between the engine crankshaft angles of 180 ° and 360 °). This is the movement of the exhaust valve 30 which is suitable for the positive energy mode operation of the engine. Figure 2a shows that the valve 100 is opened when the compression release protrusion 42b on the cam 40 passes the master piston 60 (near the crankshaft angle of the engine of 0 ° or 720 °). The exhaust valve 30 will therefore not open in response to the projection 42b. Otherwise, Figures 2c and 2d show the valve 100 which is closed near the upper dead center of each compression stroke of the engine cylinder (crankshaft angle of engine 0 ° or 720 °) although it opens during the exhaust stroke of the engine. that cylinder. This causes the exhaust valve 30 to open as shown in Figure 2d to respond to the compression release projection 42b passing the master piston 60 while allowing the exhaust valve 30 to remain closed as the exhaust projection 42a passes. the master piston 60. Figures 2e and 2f show that the valve 100 associated with the intake valve of the engine cylinder is closed during the intake stroke of the engine cylinder between the angles of the engine crankshaft of 360 ° and 540 ° ). This causes the intake valve 30 of that cylinder to open as shown in Figure 2f in response to an intake projection on an intake valve control cam 40 associated with that engine cylinder. In this mode the operation of the intake valve remains the same for the operation of positive energy mode and engine braking of the engine compression release. Additionally or alternatively to allow the selection of which cam projections 42 will respond to the engine valves 30, the apparatus of this invention allows the response of the valves of the motor 30 to any cam projection to be varied if desired. For example, Figures 3a and 3b are respectively similar to Figures 2a and 2b although they show that if the control circuit 110 delays the closing of the valve 100 in some way (as compared to Figure 2a) the valve 30 starts to open somehow later. In other words, the first part of the escape projection 42a is suppressed or ignored. In addition, because some hydraulic fluid is allowed to escape from the subcircuit 64 during the initial part of the exhaust projection 42a, the valve 30 does not open as far as in Figure 3b and as it does in Figure 2b and valve 30 closes faster in Figure 3b than in Figure 2b. The principles illustrated by Figures 3a and 3b are equally applicable to any of the other types of valve movement shown in the group of Figure 2. Figures 4a and 4b show another example of the use of valve 100 to modify the response of the valve of the motor 30 for the cam projection 42a. Again, Figures 4a and 4b are respectively similar to Figures 2a and 2b, although they show the control circuit 110 reopening the valve 100 faster than what is shown in Figure 2a. As shown in Figure 4b this causes the motor valve 30 to close faster than in Figure 2b. The reopening of the valve 100 before the final portion of the cam projection 42a has passed the master piston 60 which causes the valve 30 to ignore that final portion of the cam projection, thereby allowing the valve 30 to close again faster than it would under full control of the cam. Again, the principles illustrated by Figures 4a and 4b are equally applicable to any other type of valve movement shown in the groups of Figure 2 or Figure 3. Figures 5a and 5b show yet another example of use of the valve 100 to modify the response of the motor valve 30 to the cam projection 42a. Again, Figures 5a and 5b are respectively similar to Figures 2a and 2b. Figure 5a shows the control circuit 110 opening the associated valve 100 briefly as the exhaust projection 42a approaches its peak. This allows some hydraulic fluid to escape from the subcircuit 64, thus preventing the valve 30 from being opened much further than in Figure 2b. As another consequence, the valve 30 is opened somehow sooner than in Figure 2b. ., Another example of modulation of the valve 100 of the general type shown in Figure 5a is illustrated by Figures 6a and 6b. Again, Figures 6a and 6b are respectively similar to Figures 2a and 2b, except that during the last portion of the escape projection 42a of the control circuit 110 begins to quickly open and close the valve 100. This allows some hydraulic fluid from the subcircuit 64, which accelerates the closing of the valve 30, although the closing valve 30 still remains partially under the control of the exhaust projection 42a. The principles illustrated by Figures 5a to 6b are equally applicable to any other of the types of valve movement shown in the groups of Figure 2, Figure 3 or Figure 4. In addition, valve modulation of the type shown in FIG. Figure 6a and with any desired duty cycle (ratio of valve opening time to valve closing time) can be used at any time during a cam boss to provide any of a wide range of valve response modifications of motor associated with the cam projection. Figures 7a to 7h illustrate how the apparatus of this invention can be used to cause the engine 10 to operate in another form during compression release motor braking. Figures 7a to 7b are respectively similar to Figures 2a, 2b, 2e, and 2f and show the same operation of positive motor power mode as shown in the group of Figure 2. Figure 7e shows the control of the valve 100 associated with the valve or exhaust valves during the compression release motor braking and Figure 7c shows the control of the valve 100 associated with the intake valve or valves during compression release motor braking. Figures 7f and 7h show the movement of the exhaust and inlet valves respectively, during braking of the compression release motor. To produce the additional exhaust valve openings 120 in Figure 7f, an additional projection 42c (Figure 1) is provided on the cam 40. As shown in Figure 7e during braking of the compression release motor associated valve 100 with the valve or exhaust valves' is opened through the normal exhaust stroke of the engine to suppress the normal exhaust valve opening. However, this valve 100 is closed near the end of the expansion stroke (near the engine crankshaft angle of 540 °) and again near the end of the compression stroke (near the crankshaft angle of the 0 ° or 720 engine). °). This causes the exhaust valve 30 to be as (as in 120) in response to the cam projection 42c near the end of the expansion stroke (to load the engine cylinder with an inverse flow of gas from the exhaust manifold. the motor) . The exhaust valve 30 opens again in response to the cam projection 42b near the end of the compression stroke (to produce a compression release event for compression release motor braking). Figures 7g and 7H show that the associated intake valve 30 does not open fully during this type of compression release motor braking operation. The type of compression release motor braking operation shown in Figures 7e to 7H can be especially advantageous when the engine is equipped with an exhaust brake to substantially close the engine exhaust system when the other is retarded if desired . This increases the pressure in the exhaust manifold of the engine, making it possible to overload the cylinder of the engine when the opening of the exhaust valve 120 occurs. This overload increases the work that the engine must perform during the compression stroke, increasing in this way the delay of the release of compression that the engine can produce. Figures 2a to 7h show that the apparatus of this invention can be used to modify the responses of the motor valves to the motor cam bosses in many different ways. These include the complete omission of certain cam projections at certain times, or more disguised alteration of the regulation or extension of movement of the motor valve in response to a cam projection. These modifications can be made to change the mode of operation of the engine (for example, from positive energy mode to compression release engine braking mode or vice versa) or to optimize engine performance for various engine or vehicle operating conditions. (e.g., changes in the speed of the engine or vehicle) as detected by the engine or vehicle instrumentation 114. Figure 8 shows an alternative embodiment of the invention in which the electrically controlled hydraulic circuit of this invention is partially built into the elevated rocker arm of the engine 10a. (To the extent that the components in Figure 8 are related to the components in Figure 1, the same reference numbers are used again in Figure 8, although with a suffix letter "a." Substantially the new elements in Figure 8 it has previously unused reference numbers, although again a suffix letter "a" is added for uniformity of reference in Figure 8). As shown in Figure 8 the rocker, representative 130a is rotatably mounted on the arrow of the rocker 140a. The right portion of the rocker 130a (as seen in Figure 8) conveys a rotating cam follower roller 132a which abuts the peripheral cam surface of the rotating cam 40a. The hydraulic subcircuit 64a extends from a source of pressurized hydraulic fluid (which extends along the arrow 140a) to a slave piston 70a (which is mounted for reciprocal movement in the left portion of the rocker 130a). The last source of the pressurized hydraulic fluid in the arrow 140a may be a pump arrangement similar to the elements 78, 80 and 86 in Figure 1. The electrically controlled hydraulic valve 100a may selectively release the hydraulic fluid from the subcircuit 64a over the top of the rocker 130a. Valve 100a is controlled by the control circuit similar to element 110 in Figure 1. The apparatus of Figure 8 can be operated in a manner similar to that previously described for Figure 1. The pressure of the hydraulic fluid supply is sufficiently large to push the slave piston 70a out of contact with the upper end of the motor valve 30a. However, this pressure is not large enough to open the valve 30a against the valve closing force of the springs 32a. If the valve 100a is closed when a cam projection 42aa or 42ba passes the roller 132a, the hydraulic fluid trapped in the subcircuit 64a causes the slave piston 70a to open the valve 30a. Elsewhere, if the valve 100a is opened when a cam projection 42aa or 42ba pass the roller 132a the slave piston 70a will move within the rocker 130a, thereby ejecting some hydraulic fluid from the subcircuit 64a and allowing the valve 30a remain closed despite the passage of a cam projection 42. Any of the techniques for modifying the response of the motor valve to the cam projections that are illustrated by Figures 2a to 7h are equally applicable to the embodiment shown in the Figure 8. Therefore, it is again preferred that the available motion available in the hydraulic subcircuit 64a be sufficient to allow any protrusion on the cam 40a to be completely ignored. The more subtle modifications of the regulation and / or extension of the response to the motor valve to the cam projections are also possible as described above in relation to Figures 2a to 7h. Figure 9 shows another embodiment that is similar to the embodiment shown in Figure 8, albeit with the addition of an accumulator 90b and a check valve 84b respectively similar to the accumulator 90 and the check valve 84 in Figure 1. The elements in Figure 9 which are similar to the elements in Figure 8 have the same reference numbers, although with the suffix letter "b" instead of "a" as in Figure 8. When the valve 100b is opened, it releases hydraulic fluid from the subcircuit 64b to the accumulator 90b in a manner similar to the embodiment shown in Figure 1. In other respects the operation of Figure 9 is similar to the operation shown in Figure 8, and therefore it will not be necessary to repeat the explanation of Figure 8 for Figure 9.

Figure 10 shows another embodiment which is similar to the embodiment shown in Figure 9 although the addition of a master piston 60c (similar to the "" * master piston 60 in Figure 1) for hydraulic subcircuit 64c.The elements in Figure 10 which are similar to the elements in Figure 9 have the same reference numbers although with the suffix letter "c" instead of "b" as in Figure 9. The operation of that modality is similar to that of the modality shown in Figure 9, so that it will not be necessary to repeat the explanation of Figure 9 for Figure 10. It will be understood that the foregoing is only illustrative of the principles of the invention and that various modifications may be made by those with experience in For example, while Figures 1 and 8-10 suggest that there is an exhaust valve or intake valve 30 for each cylinder of the engine, it is very common to provide two valves for each type in each cylinder. The apparatus of this invention can be easily modified to control multiple intake and / or exhaust valves per cylinder.

Claims (27)

1. An internal combustion engine having a four-stroke positive energy mode and including a motor cylinder valve that selectively opens and closes, a cam having a plurality of projections synchronized with the possible openings of the cylinder valve motor, a hydraulic link containing hydraulic fluid operatively coupled between the cam and the motor cylinder valve to selectively respond to the projections causing the valve to open, and an electrically operated valve controlled by the electronic control circuit to selectively release the hydraulic fluid from the hydraulic link to selectively modify the openings of the motor cylinder valve in response to the projections, the electrically operated valve being selectively operable to allow the motor cylinder valve to remain fully closed in response to any one of the projections and to open n response to a second of the protrusions characterized in that the electrically operated valve opens and closes multiple times during each period (0 ° - 720 °) of engine operation comparable to every four cycles (0 ° - 720 °) of the operation of positive energy mode of the engine.

2. The motor according to claim 1, characterized in that the control circuit includes a microprocessor.

3. The motor according to claim 1, further including a supply of electric fluid in a first valve of relatively low positive pressure and check to allow the hydraulic fluid to flow from the supply into the hydraulic link, but not in an opposite direction , the first pressure being insufficient to cause the hydraulic link, open the motor cylinder valve further characterized in that the supply comprises a hydraulic fluid accumulator for maintaining a quantity of hydraulic fluid at approximately the first pressure and wherein the electrically operated valve selectively releases the hydraulic fluid from the hydraulic link to the accumulator.

4. The motor according to claim 1, characterized in that the hydraulic link is placed on a rocker arm that swings in response to the projections.

5. The motor according to claim 4, characterized in that the hydraulic link comprises a slave piston placed on the rocker arm, the slave piston being movable reciprocally relative to the rocker arm in response to the hydraulic fluid pressure and flowing in the hydraulic link to selectively open the cylinder valve of the engine.

6. The motor according to claim 1, characterized in that the hydraulic link is placed on a rocker arm that is selectively balanced in response to the projections.

7. The motor according to claim 6, characterized in that the hydraulic link comprises a master piston that moves reciprocally with respect to the rocker arm in response to the projections and a slave piston that moves reciprocally relative to the arm of the arm. rocker in response to a hydraulic fluid pressure and flowing in the hydraulic link to selectively open the cylinder valve of the engine.

8. The motor according to claim 1, characterized in that the valve of the motor cylinder is an exhaust valve, wherein the projections include an exhaust projection and a compression release projection, and wherein the electrically operated valve responds to the motor, is in a positive energy operation mode or in a compression release motor braking operation mode by controlling the hydraulic fluid pressure in the hydraulic link so that the exhaust valve opens in response to the outgoing compression release only when the engine is in compression release motor braking operation mode.

9. The engine according to claim 8, characterized in that the electrically operated valve further responds to the mode of engine operation by controlling the hydraulic fluid pressure in the hydraulic link so that the exhaust valve opens in response to the exhaust projection only when the engine is in positive energy operation mode.

10. The motor according to claim 8, characterized in that the cam further has a reverse exhaust gas flow protrusion, and wherein the electrically shut-off valve further responds to the operation mode of the engine by controlling the hydraulic fluid pressure in the hydraulic link so that the exhaust valve opens in response to the reverse exhaust gas flow projection only when the engine is in the compression release engine braking mode.

11. The motor according to claim 1, characterized in that the electrically operated valve selectively delays an opening of the motor cylinder valve in response to a second of the projections substantially preventing the hydraulic fluid pressure from increasing in the hydraulic link during a portion. initial of the outgoing.

12. The motor of, according to claim 1, characterized in that the electrically operated valve selectively reduces the amount by which the motor cylinder valve opens in response to the second of the projections allowing the hydraulic fluid to escape from the hydraulic link during a portion of that outgoing.

13. The motor according to claim 1, characterized in that the electrically operated valve advances selectively in time to return the new closing of the motor cylinder valve after the opening in response to the second of the projections allowing the hydraulic fluid to escape from the hydraulic link during a portion of said projection.

14. The method of operation of an internal combustion engine having a selectively opening motor cylinder valve, a cam having an exhaust projection and a compression release projection, and a hydraulic link containing the hydraulic fluid operatively coupled between the cam and the motor cylinder valve to selectively respond to said exhaust and compression release by selectively opening the motor cylinder valve, the method including the steps of detecting whether the motor is in a positive energy mode of operation or in a compression release engine braking operation mode and if said engine is in the positive energy operation mode, controlling the hydraulic fluid pressure in the hydraulic link so that the hydraulic link opens the cylinder valve of motor in response to the escape projection although not in response to the compression release projection, or if the engine is in the operation compression release mode, controlling the hydraulic fluid pressure in the hydraulic link so that the hydraulic link opens the engine cylinder valve in response to the compression release protrusion, characterized in that In the compression release operation mode, the hydraulic fluid pressure in the hydraulic link is controlled so that the motor cylinder valve does not open in response to the exhaust projection.

15. The method according to claim 14, characterized in that the control step, when the engine is in the compression release motor braking operation mode, comprises the steps of trapping the hydraulic fluid in the hydraulic link during the response of the hydraulic link to the compression release projection, and allowing the hydraulic fluid to escape from the hydraulic link during the response of the hydraulic link to the exhaust projection.

16. The method according to claim 14, characterized in that at least one of the control stages comprises the steps of retaining the hydraulic fluid in the hydraulic link during a first portion of the response of the hydraulic link to at least one of the projections and allowing part of the hydraulic fluid to escape from the hydraulic link during a second portion of the response of the hydraulic link to at least one of the projections.

17. The method according to claim 16, characterized in that the second portion is an initial portion of the response of the hydraulic link for at least one of the projections.

18. The method according to claim 16, characterized in that the second portion is an intermediate portion of the response of the hydraulic link to at least one of the projections.

19. The method according to claim 18, characterized in that the first portion precedes the intermediate portion.

20. The method according to claim 19, characterized in that at least one of the control stages further comprises the step of recapturing the hydraulic fluid in the hydraulic link during a third portion of the response of the hydraulic link to at least one of the projections, and a third portion following the intermediate portion.

21. The method according to claim 16, characterized in that the portion is a final portion of the response of the hydraulic link to at least one of the projections.

22. A compression release braking system for an internal combustion engine including a motor cylinder exhaust valve which selectively opens and closes, a cam having a projection synchronized with a possible opening of the exhaust valve, a hydraulic link containing the hydraulic fluid operatively coupled between the cam and the exhaust valve to selectively respond to the projection causing the valve to open, and a control of the hydraulic fluid having a plurality of different operating conditions in which the Hydraulic fluid control has respective different effects on the present hydraulic fluid in the hydraulic link in response to the projection, characterized in that the projection is a braking projection of compression release motor synchronized with a possible compression release opening of the valve exhaust and hydraulic fluid control responds to a variable operating condition of the motor changing the operating condition on different occasions during the response of the hydraulic link to the outgoing.

23. The system according to claim 22, characterized in that the hydraulic fluid control comprises a microprocessor.

24. The system according to claim 22, characterized in that the hydraulic link is placed on a rocker arm that is selectively balanced by the projection.

25. The system according to claim 22, characterized in that the hydraulic fluid control selectively modifies the start time of the openings in relation to the start time of the projection.

26. The system in accordance with the claim 22, characterized in that the hydraulic fluid control selectively modifies the final termination time of the openings in relation to the final termination time of the projection.

27. The system according to claim 22, characterized in that the hydraulic fluid control selectively modifies the opening distance of the openings relative to the profile projection of the projection.