JPH0233850B2 - - Google Patents

Abstract

A compression release engine retarder for a multi-cylinder four-stroke cycle engine is disclosed. The retarder incorporates an hydraulic pulse generator (85) which in one embodiment comprises a multi-chamber positive displacement pump of the piston (146) and cylinder (144) type which is positively driven at engine speed or at half engine speed in synchronism with the engine crankshaft (86). Means (84,96,97) are provided to adjust the timing of the hydraulic pulses so as to control precisely the opening of the engine exhaust valves and to maximize the compression release retarding power developed by the engine. Additional means (182,184,186,188,190,192,194) are provided to control the timing of the hydraulic pulses in response to the boost pressure in the engine inlet manifold produced by the engine turbocharger.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates generally to engine retarders for use in multi-cylinder four-stroke internal combustion engines. More particularly, the present invention relates to a hydraulic pulse generator for sequentially opening exhaust valves of an internal combustion engine to provide a decompression engine deceleration function during braking operations.

(Prior Art) It is known that drum-type or disc-type wheel brakes can absorb a large amount of energy in a short period of time. The absorbed energy is converted to heat, causing the temperature of the braking mechanism to rapidly rise to a level that renders the friction surfaces and other parts of the mechanism ineffective. Repetitive use of wheel brakes under these conditions is impractical, so auxiliary deceleration devices are relied upon.

This type of auxiliary equipment is equipped with a hydraulic or electric speed reducer and is capable of converting the dynamic energy of the vehicle into heat by means of fluid friction or magnetic vortices, which can be dissipated via suitable heat exchangers. can. Other auxiliary reduction devices include (a) exhaust brakes that prevent the flow of exhaust gases or air through the exhaust system and (b) decompression retarder mechanisms that compress intake air during the compression stroke of a four-stroke engine. The required energy is dissipated by exhausting compressed air through the exhaust system during the engine's expansion stroke. In the case of an engine decompression retarder, a portion of the vehicle's dynamic energy is dissipated through the engine cooling system and another portion of the dynamic energy is dissipated through the engine exhaust system. In the case of exhaust braking, the dynamic energy of the vehicle is dissipated only as heat via the engine cooling system.

One major advantage of engine decompression retarders and exhaust brakes over hydraulic and electric retarders is that the former retarders are bulky and expensive compared to the mechanisms required for conventional exhaust brakes or engine decompression retarders. It requires some dynamo or turbine equipment. A typical engine decompression retarder is shown in U.S. Pat. No. 3,220,392 to Kumins, and an exhaust brake is disclosed in U.S. Pat. No. 4,054,156 to Benson. Other mechanisms for providing decompression braking are described in U.S. Pat. No. 3,809,033;
It is disclosed in Publications No. 3547087, No. 3859970, and No. 3367312.

Other advantages of engine decompression retarders, such as those shown in U.S. Pat. It is only necessary to add.

PROBLEM TO BE SOLVED BY THE INVENTION The problem with using engine valves or fuel injection pushers as a source of motion, such as occurs with Cumins-type decompression retarders, is that the forces may differ from those contemplated in the original engine design. As a result of applying a much stronger force to the valve mechanism, damage to the injection pusher tube can result. Furthermore, for this kind of arrangement, the timing of the decompression operation is
It is necessarily determined by valve operation that is not optimal for the deceleration function occurring elsewhere in the engine.

One way to solve the aforementioned problem of creating excessive stress on the valve mechanism is shown in U.S. Pat. No. 4,271,796, in which a decompression device is incorporated into the hydraulic system to limit the maximum pressure that can develop therein. . The use of relief valves for this purpose is disclosed in the U.S. Patent No.
It is disclosed in Publication No. 4150640.

By using hydraulic pulses generated by a hydraulic pulse generator that is actively driven in synchronization with the engine crankshaft, the inventors have discovered that (a) improved engine deceleration and (b) engine valve It has been found that complete prevention of the risk of damaging the mechanism can be achieved.

(Means for Solving the Problems) More specifically, according to the present invention, a crankshaft, an intake and exhaust manifold, at least one exhaust valve for each cylinder, and a crankshaft, an intake and exhaust manifold, and at least one exhaust valve for each cylinder, the exhaust valve being activated during a braking operation. a decompression engine retarder for use in a multi-cylinder four-stroke internal combustion engine having at least one slave piston for synchronous opening, the decompression engine retarder being actively driven synchronously with the engine crankshaft to generate pulses of hydraulic fluid; a rotary hydraulic pulse generator that sequentially supplies under pressure to predetermined slave pistons by means of a duct, said duct interconnecting said slave pistons and said hydraulic pulse generator; A common valve control is provided in an associated manner to establish the low pressure fluid conditions in the duct which occur during fuel supply operations when the valve control is not actuated and when the valve control is actuated during braking. provides a decompression engine retarder for establishing high pressure fluid conditions in the duct.

A hydraulic pulse generator generates hydraulic pulses timed to coincide with the beginning of the expansion or power stroke of each cylinder in a four-stroke engine. This hydraulic pulse generator can be driven by a shaft operating at engine speed or at half engine speed. The timing can be adjusted over a wide range by varying the position of the pulse generator and its drive shaft relative to the engine crankshaft, and the magnitude of the pulses can be determined by the design of the pulse generator. Furthermore, the timing can be adjusted as a function of boost to more accurately control the decompression operation.

BRIEF DESCRIPTION OF THE DRAWINGS Objects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

The basic operation of decompression engine retarders is currently well known in the art and therefore need not be described in detail here. However, in brief, the well-known decompression retarder involves moving an element in the valve system or fuel injection system, typically a push tube, in close proximity to a desired timing, and with this movement driving a master piston. . The master piston is hydraulically interconnected with a slave piston that opens an exhaust valve (or dual exhaust valve) at or near the beginning of the expansion or power stroke of the four-stroke engine during braking. It works like this. If the decompression engine retarder is activated, since this is a braking period, the fuel supply is automatically cut off and the engine supplies only air. By opening the exhaust valve at the beginning of the engine's expansion or "power" stroke, the work done in compressing the air during the compression stroke is not recovered during the expansion stroke, but rather the engine exhaust and cooling systems. is dissipated through.

The energy absorbed by the engine can be measured by an electric dynamometer as the number of decelerating horsepower produced by the engine. Of course, the total deceleration effect includes the energy losses exhibited by the internal friction of the engine and all other losses associated with engine appurtenances. The absolute value of the reduced horsepower number produced during decompression deceleration is a substantial portion of the positive horsepower number produced by the engine during normal refueling operations.

Reference will now be made to FIG. 1, which shows various exhaust valve movements. In FIG. 1, exhaust valve motion is plotted on the vertical axis and crank angle starting at top dead center (TDC) is plotted on the horizontal axis. Curve 10 shows the normal operating pattern of the exhaust valve at the beginning of the engine's exhaust stroke. Curve 12 shows typical exhaust valve motion for an engine with a compression brake designed to open the exhaust valve as close as possible to top dead center at the beginning of the engine's expansion stroke. More specifically, curve 12 shows the exhaust valve movement imparted by the fuel injection push tube. The motion represented by curve 12 can be produced, for example, by the apparatus described in the above-mentioned US Pat. No. 4,271,796 to Schickler et al. Curve 16 shows the desired optimal movement of the exhaust valve to maximize the dissipation of the power stored in the engine during the compression stroke. It is understood that the precise timing of opening the decompression exhaust valve should be selected to maximize the work of compression and minimize recovery of that maximized work during the subsequent expansion stroke. Good morning. This means that the valve opens rapidly near the end of the compression stroke and close to the top dead center position. However, if the valve actuation movement originates from other parts of the engine, such as a fuel injection push tube or an exhaust push tube for another cylinder, it is not possible to obtain optimal operation of the decompression mechanism.

FIG. 2A is a graph of volume versus time for a positive displacement pulse generator, such as the piston pump 18 of FIG. 2B. Pump 18 includes a shaft 20 that drives a crank 22 that drives a connecting rod 24 that is fixed to a piston 26 that is constrained to move within a cylinder 28 . It will be observed that the positive portion of displacement curve 30 is similar to optimal valve travel curve 16 of FIG.
A portion of the displacement curve 30, for example the portion above line 32, therefore acts as a valve actuation pulse if properly timed.

3A-3F, which sequentially illustrate the operation of a decompression engine retarder according to the present invention using a three-unit pulse generator. The engine block of a six-cylinder, four-stroke internal combustion engine is shown in fragments at 34. Cylinder No. 1 is designated by the reference numeral 36 and contains a piston 38.
Cylinder No. 6 is designated by the reference numeral 40 and contains a piston 42 . In the particular engine shown, the pistons for cylinders No. 1 and 6 reach top dead center (TDC) at the same time and move in unison. However, if piston No. 138 moves upward during the exhaust stroke, piston No. 642 moves upward during the compression stroke. It will be appreciated that cylinders Nos. 2 and 5 and cylinders Nos. 3 and 4 are similar pairs. The operation of the present invention will be explained with reference to the sequential operations related to cylinders No. 1 and 6.
It will be appreciated that similar operations may occur for other cylinders at different times.

The intake valve 44 for cylinder No. 136 is normally biased to a closed position by a valve spring 46. Similarly, suction valve 4 for cylinder No. 640
8 is also biased into the closed position by valve spring 50.
Inlet valves 44, 48 can be actuated by swinging arms (not shown).

Exhaust valve 52 for cylinder no. 136 is biased to its closed position by valve spring 54. The exhaust valve 52 is opened by a swinging arm 56 driven by an engine camshaft (not shown) and acting through a crosshead 58 during the refueling cycle of engine operation. A slave piston 60 is mounted for reciprocating movement within a slave piston cylinder 62, which cylinder is formed within a housing 64 secured to an engine head 63, which is secured to the engine block 34. Subordinate piston 60
is biased away from crosshead 58 by spring 65.

Similarly, exhaust valve 66 for cylinder No. 640
is also biased to its closed position by valve spring 68. The exhaust valve 66 is opened by a swinging arm 70 acting through a crosshead 72 during a refueling cycle. A slave piston 74 is reciprocatingly mounted to a slave piston cylinder 76 formed within the housing 64. Subordinate piston 74
is biased away from crosshead 72 by spring 78.

The duct 80 is connected to the subordinate piston cylinders 62, 7
6 and a master cylinder 82 formed within a housing 84 of a pulse generator 85 .
The master cylinder 82 is a pulse generator drive shaft 86
disposed within the housing 64 in a radial direction relative to the
The drive shaft 86 may be any engine accessory or auxiliary drive shaft that operates at engine speed and is actively driven, directly or indirectly, by the engine crankshaft to maintain synchronization therewith. . Master cylinders 88 and 90 are also radially disposed relative to drive shaft 86 and spaced apart from each other and from master cylinder 82 by an arc of 120 degrees. Duct 92 runs from master cylinder 88 to slave piston cylinder (not shown).
These slave piston cylinders are identical to slave piston cylinders 62 and 76, but are interlocked with engine cylinders Nos. 2 and 5. Similarly, the duct 94 is connected to the master cylinder 90
extending from to a third pair of slave piston cylinders (not shown), which slave piston cylinders are identical to slave piston cylinders 62 and 76, but are interlocked with engine cylinders Nos. 3 and 4.
Eccentric 96 is secured to drive shaft 86 which is driven counterclockwise as shown in Figures 3A-3F. The rotation of the drive shaft 86 is caused by an eccentric 96 against a ring 97.
, said ring 97 contacts master pistons 98 , 100 and 102 mounted for reciprocating motion within master cylinders 82 , 88 and 90 , respectively, to sequentially move the pistons radially outwardly from drive shaft 86 . let Eccentric 96 allows master pistons 98, 100 and 102
The motion imparted to is functionally equivalent to the motion produced by the slider crank mechanism shown in FIGS. 2A and 2B. Details regarding the structure of pulse generator 85 are further described below with respect to FIGS. 4 and 5.

Referring to Figure 3A, piston 3 of cylinder No. 1
8 starts moving upward during the exhaust stroke, and the cylinder
No. 6 piston 42 begins to move upward during the compression stroke. Ring 9 driven by eccentric 96
7 also begins to move the master piston 98 radially outward. At this point, exhaust valves 52 and 6
6 is still closed and the master piston 98
has moved sufficiently to isolate the duct 80 and the hydraulic fluid contained therein from the low pressure hydraulic fluid supply within the eccentric chamber 104 of the pulse generator. This is the third
The L-shaped passageway 1 in the master piston 98 is shown in Figure A and communicates the duct 80 with the eccentric chamber 104 when the master piston 88 is in the radially inward position.
06 is not in communication with the eccentric chamber 104 in this case.

Figure 3B shows the decompression mechanism at a point slightly later than when swing arm 56 opens exhaust valve 52 in the normal valve opening sequence required for the normal exhaust stroke of cylinder No. 136. . When the exhaust valve 52 and its crosshead 58 are displaced downwardly, the movement of the slave piston 60 is restrained only by the bias of the spring 65. As shown in detail in FIG. 3G of the slave piston housing 64, the slave piston 60 has an upper cylinder portion;
up to a contact portion 108 defined by the upper end of said groove opposite a stop 110 mounted on the housing 64 and extending across said groove; can be slidably moved in the subordinate piston cylinder 62;
A spring 65 is disposed between the upper wall of the slave piston cylinder 62 and the stop 110 to bias the slave piston 60 toward the top of the slave piston cylinder. As a result, as the pressure within duct 80 increases due to the radially outward movement of master piston 98, hydraulic fluid flows into slave cylinder 62, causing contact 108 on slave piston 60 to contact housing 64. The subordinate piston 60 is driven downward until it abuts the installed stop 110. The movement of the slave piston 60 that occurs while the hydraulic fluid in the duct 80 is still at a relatively low pressure has no effect on the exhaust valve 52 controlled by the rocking arm 56 during this time. will be understood.
As soon as the pressure in the duct 80 is high enough to overcome the bias of the spring 65 in the slave piston cylinder 62, it also overcomes the bias of the spring 78 in the slave piston cylinder 76, causing the slave piston 74
contacts the crosshead 72, thereby closing the clearance normally existing between each slave piston and its associated exhaust valve when the duct 80 is in communication with the low pressure present in the eccentric chamber 104. However, slave piston 74 does not open exhaust valve 66 at this point. This is because the force required to open valve 66 causes slave piston 74 to force spring 7
8 and therefore only movement of the slave piston 74 occurs.

FIG. 3C shows the decompression mechanism when master piston 98 has reached its maximum stroke. At this point, the hydraulic pressure in the duct 80 has reached a high level and the biasing force of the valve spring 68 and the cylinder no.
0 is sufficient to overcome the force on valve 66 due to the air compressed in 0 and opens exhaust valve 66.
The movement of the master piston 98 is controlled by the position of the eccentric 96, and the exhaust valve 66 is controlled by the position of the eccentric 96.
It will be appreciated that it is opened close to the TDC position to maximize the deceleration horsepower produced by the engine. This ensures that the maximum amount of work is done compressing the air in the compression step and that the least portion of the work done is recovered during the subsequent expansion step.

Figure 3D shows the mechanism in which the eccentric 96 has been moved to the point where the master piston 98 has been substantially retracted to the position shown in Figure 3B. As a result of the master piston 98 retracting, the pressure within the slave cylinder 76 decreases to the point where the valve spring 68 closes the valve 66. Meanwhile, the swing arm 5
6 swings back to its initial position and the valve spring 54 closes the exhaust valve 52. As the exhaust valve 52 closes, the slave piston 60 is driven upward. It will be seen that axis 86 has moved by an angle slightly less than 90 DEG, as indicated by the arcuate motion of dashed line 112 between FIGS. 3A and 3D. Then, upon movement of the drive shaft by approximately 30 degrees, the master piston 98 retreats, causing the duct 80 to communicate with the eccentric chamber 104 through the L-shaped passage 106, thereby reducing the pressure in the duct 80 and the pressure in the eccentric chamber 104. to balance. Under these conditions, the bias of springs 65 and 78 will cause slave pistons 60 and 74 to move toward crossheads 58 and 72, respectively.
This is sufficient to move the object away from the object. As can be seen from the position of dashed line 112 in FIG. 3D, successive crankshaft rotations, i.e. rotations of pulse generator drive shaft 86, cause eccentric 96 to move master piston 100 radially outward;
The cycle of operation of cylinders No. 2 and 6 is therefore initiated in the same manner as described above for cylinders No. 1 and 5. Continued rotation of the pulse generator drive shaft 86 then transfers these cyclic movements for cylinders Nos. 3 and 4 to the master piston 102.
repeat as a result of the movement of

FIG. 3E shows the state of the decompression mechanism when the eccentric 96 reaches the master piston 98 again. At this point, cylinder No. 640 has begun its exhaust stroke and cylinder No. 136 has begun its compression stroke. In these conditions, the swing arm 70 swings downward against the crosshead 72, opening the exhaust valve 66. Thereafter, as the pressure within duct 80 begins to rise, hydraulic fluid flows into slave cylinder 76 and forces slave piston 74.
The slave piston 74 is moved downward until the contact portion 114 abuts a stop 116 mounted on the housing 64 . As mentioned above, hydraulic fluid again flows into the slave cylinder 62 to move the slave piston 60 downwardly into contact with the crosshead 58.

FIG. 3F is substantially similar to FIG. 3C above, except that the master piston 96 has moved to its outer end position and increased the pressure in the duct 80 so that the slave piston 60 opens the exhaust valve 52. It shows the points to be made. Again, this condition is top dead center (TDC)
Occurs close to the location. Pulse generator drive shaft 86
Continued rotation of reduces the pressure within duct 80, causing exhaust valve 52 to close, and eventually slave pistons 60 and 74 return to their rest position.
This operating sequence is repeated for cylinders Nos. 2 and 5 as well as cylinders Nos. 3 and 4.

During two revolutions of the pulse generator drive shaft 86, corresponding to two revolutions of the engine crankshaft, each of the engine cylinders undergoes a decompression movement near the end of the compression stroke and near the top dead center position of the piston.

Reference will now be made to Figures 4A and 4B, which show enlarged views of the pulse generator shown in Figures 3A and 3F. Figures 4A and 4B also include a timing advance mechanism, a pressure relief mechanism, an electromagnetic switch controlling the pulse generator, and other master piston structures. The pulse generator 85 consists of a housing 84 containing an eccentric chamber 104. Master cylinders 82, 88 and 90 are spaced 120 degrees apart radially around eccentric chamber 104. Duct 118 guides a low pressure hydraulic fluid, such as oil, to eccentric chamber 104 and then through master cylinders 82, 88 and 90 to duct 80 and slave cylinders 62, 76. Similarly, hydraulic fluid is guided to the ducts 92, 94 and their corresponding slave cylinders.

The operation of the pulse generator 85 is controlled by a solenoid valve 120 consisting of a solenoid coil 122, a moving iron disk 124, a control rod 126, and a ball valve 128 seated in a valve seat 130. Ball chamber 132 communicates with a drain (not shown). Beyond the ball valve seat 130 is a disk valve chamber 134 . Passages 136, 138, and 140 are connected from the disk valve chamber 134 to the master cylinder 8, respectively.
It extends to 2,88,90. Disc valve 142
is movably located within the disc valve chamber 134.
When the solenoid valve is deenergized as shown in Figure 4A,
The movable iron disk 124 is released from the magnetic force of the coil 122, and the control rod 126 and ball valve 128 move to the right (as shown in FIG. 4A), draining the hydraulic fluid from the disk valve chamber 134 from the housing 85. Let it liquefy. This action moves the disc valve 142 to the right, thereby causing the disc valve chamber 134 to
acts as a manifold for passages 136, 138 and 140. When the disc valve 142 opens, the master pistons 98, 100, 102
It will be appreciated that the hydraulic fluid pumped sequentially by the pumps returns to the eccentric chamber 104. It will be appreciated that when one master piston is pumping, the other two master pistons (and their associated passageways) are draining.

However, when coil 122 is energized,
The movable iron disk 124 is pulled to the left, moving the control rod 126 and ball valve 128 to the left, thereby closing the disk valve chamber 134. Once the disc valve chamber 134 is closed, the disc valve 1
Since the pressure of the hydraulic fluid on the right side of 42 is established,
The openings to passageways 136, 138, and 140 are closed. When the eccentric 96 is driven into the master piston 98 as shown in FIG. 4B, the passage 13
The high pressure from 6 is transferred to the low pressure passage 13 by the disc valve 142.
8 and 140, so that the low pressure passages 138 and 140 are connected to a drain. This then allows high pressure hydraulic fluid to flow into the duct 80 to perform the functions described above.

As shown in FIGS. 4A and 4B, the master pistons 98, 100, and 102 are each comprised of three parts: a cylindrical shell 144, an internal sliding piston 146, and a snap ring 148, the snap ring being connected to the internal piston 164. and the cylindrical shell 144. Eccentric 96 and ring 97 first sealingly engage piston 146 to cylindrical shell 144 and then master piston 98 (or 100, 10
2) by moving these parts radially outward,
It will be appreciated that this creates the necessary hydraulic pressure within the duct 80 (or 92, 94).

4A and 4B further illustrate pressure control mechanism 150 inserted within duct 80. FIG.
Corresponding ducts 92 reaching cylinders No. 2 and 5
and ducts 94 reaching cylinders No. 3 and 4.
It will be understood that a similar mechanism could be installed in Pressure control mechanism 150 includes diametrical passage 15
4, the passage 154 communicating with the duct 80 and the axial passage 15 terminating the duct into a cylindrical chamber 158.
Connect to 6. The piston 160 is attached to the housing 1
52 for reciprocating movement within a cylindrical chamber 158 and biased toward the axial passageway 156 by a relatively stiff spring 162. Spring 162 and piston 160 are held in place by a cap 164 threaded onto housing 152.

In operation, the pressure control mechanism 150 acts as a type of shock absorber, limiting the maximum pressure that can be produced by the pulse generating mechanism 85 by increasing the volume of the hydraulic circuit when the pressure exceeds a predetermined level. . As will be understood by those skilled in the art, when the hydraulic circuit is relatively short, the bulk modulus of the hydraulic fluid is such that the fluid can be considered to be substantially incompressible, and some form It is desirable that the pressure control mechanism relieves excess pressure in the system. However, if the hydraulic path is relatively long, the compressibility of the hydraulic fluid is sufficient to effectively form its own expansion chamber. Instead of the above pressure control mechanism,
Other devices can also be used, such as bourdon tubing that expands with pressure. In any event, whether or not a particular pressure control mechanism is used, the ducts 80, 92, and 94 have approximately the same length and contain approximately the same amount of hydraulic fluid to act on each dependent cylinder. Care must be taken to ensure that they are the same.

Additionally, the pulse generator 85 includes a timing advance mechanism that allows the timing of the hydraulic pulses to be varied as a function of the boost generated by the engine turbocharge (if the engine is equipped with this). It will be appreciated that the pressure build-up in the engine inlet manifold varies with the speed of the turbocharger and that the amount of air introduced into the engine is also a function of the pressure build-up. Additionally, the pressure developed within the engine cylinder during the engine's compression stroke varies with the amount of air introduced into the cylinder during the engine's intake stroke, and the force required to open the exhaust valve is is a function of the pressure within the engine cylinders.

FIG. 6 shows a family of curves plotting the force required to open the engine exhaust valve on the vertical axis and the crank angle on the horizontal axis. curve 166
shows how this force varies with crank angle for low boosts, and curve 168 shows a similar curve for high boosts. It will be appreciated that the engine may be operated at various pressure increases within the range shown by curves 166 and 168.

If it is desired to begin opening the exhaust valve at a particular point, e.g. 15 degrees B, T, D, C, to maximize the decompression deceleration effect, the master piston 98
It will be appreciated that an initial movement of (or 100, or 102) must precede this point. The slope of line 170 is similar to the hydraulic system, e.g.
The pressure in 0, 92 and 94 increases as a function of time (or crank angle) during low pressure increases;
It shows the speed to achieve the force required to open the exhaust valve as shown at point 172. line 17
The intersection of 0 and the axis (point 174) indicates the crank angle at which master piston movement begins to open the exhaust valve at point 172. Similarly, point 176 on the high pressure rise curve 168 indicates the force required to open the exhaust valve at 15 degrees B, T, D, and C under high pressure conditions. To obtain this power,
The pressure in the hydraulic system increases along line 178;
and intersects the axis at point 180. As can be seen from FIG. 6, it is desirable to have a mechanism that automatically adjusts the timing of movement of the master piston in response to pressure increase.

This type of mechanism is shown in Figures 4A and 4B.
Boss 182 integrally formed with housing 84
includes a cylindrical hole 184 communicating at one end with a duct 188 via a passage 186;
8 communicates with an engine intake manifold (not shown). This intake manifold is constantly subject to a pressure increase caused by the engine turbocharger (not shown). A piston 190 is placed within the cylindrical bore 184 and biased toward the passageway 186 by a spring 192 . A trilobal cam 194 is mounted on the drive shaft 86 so that it can rotate independently of the eccentric 96 and ring 97. The cam 194 is axially offset from the eccentric 96 so that each piece of the cam 194 contacts the sliding cylindrical shell 144 of one of the pistons 98, 100 or 102, but not the inner sliding piston 146. do. fitting 196
interconnects cam 194 and piston 190.

At low pressure increases, the piston 190 is biased to the left (as viewed in FIG. 4A), causing the cam 194 to force the cylindrical shells 144 of the pistons 98, 100, and 102 radially outwardly from the drive shaft 86 in a counterclockwise direction. Rotate to the point where it is driven. As shown in FIG. 4B, upon high pressure increase, the piston 190 is driven to the right and the cam 194 rotates clockwise. This rotation of the cam 194 causes the piston 98,1
00 and 102 allow cylindrical shells 144 to move radially inwardly in the direction of axis 86.
The movement of the cylindrical shell 144 advances the movement of the master pistons 98, 100 and 102 inwardly relative to the drive shaft 86, which movement is synchronous with the engine crankshaft. Thus, the timing of master piston movement is a function of pressure increase. As a result, the exhaust valve is opened during the decompression deceleration operation at some point (eg, 15 degrees B, T, D, C), regardless of changes that may occur in pressure build-up, for example as a result of changes in engine speed.

Referring now to FIG. 5, the pulse generator drive shaft 86' operates at half the speed of the engine crankshaft.
Other embodiments of the invention are described for use with the invention. In FIG. 5, parts common to FIGS. 3 and 4 are designated by the same reference numerals, and modified parts are designated by a dash "'". Housing 8
4' are cylinders No. 6 and 4, respectively, during decompression operation.
six master cylinders 198 for controlling the opening of exhaust valves for 2, 4, 1, 5 and 3;
200, 202, 204, 206 and 208 are built in. Master cylinder 198, 200, 2
02, 204, 206 and 208 are arranged in the same order as the engine firing order. Passage 210,
212, 214, 216, 218 and 220 are master cylinders 198, 200, 20, respectively.
2, 204, 206, and 208 and six ball check valve chambers, only three of which are illustrated as chambers 222, 226, and 230. The other three ball check valve members are located behind chambers 222, 226 and 230, respectively, and are therefore not visible in FIG. Each ball check valve chamber is equipped with a seat 234, a ball check valve 236, and a spring 238 that normally biases the ball check valve 236. Each of the six ball check valve chambers communicates with the armature manifold chamber 240 through six passageways, only three of which are illustrated as 242, 246, and 250. The other three passages are located behind passages 242, 246 and 250, respectively, and are therefore not visible in FIG. armature 25
4 is placed in the movable iron disk manifold chamber 240.

Hydraulic fluid passage 256 is connected to armature manifold chamber 2
40 and duct 258 to supply hydraulic fluid to pulse generator 85'. The electromagnetic coil is shown at 260 and the leads to the electromagnetic coil are shown at 262 and 264. A relatively stiff spring 266 is seated in a hole 268 formed in the electromagnetic core and is normally connected to the armature 254.
is biased away from coil 260. control rod 27
0 to armature 254 and passages 242, 246 and 2
50 as well as the ball check valve 236 in three invisible passages.

Master piston 272, 274, 276, 2
78, 280 and 282 as master cylinder 1
98, 200, 202, 204, 206 and 2
08, and these are connected to the ring 97 and the eccentric 9.
6 from the drive shaft 86'. The duct 284 communicates between the master cylinder 198 and a subordinate cylinder (not shown) that is linked to engine cylinder No. 6. Duct 286, 288, 29
0,292,294 are the engine cylinders respectively
Nos. 2, 4, 1, 5 and 3 are connected to slave cylinders (not shown). Figures 4A and 4B
A pressure control mechanism 15 similar to that described in connection with the figures.
0 to duct 284, 286, 288, 290, 2
92 and 294, respectively. A circular eccentric 296 is mounted adjacent to the cam 96 on the shaft 8.
6' and can be fixed to or rotatable relative to this shaft 86'. In any case, the cam 296 is connected to the master piston 272, 2
74, 276, 278, 280 and 282, respectively.

The operation of the mechanism shown in FIG. 5 is as follows. When the electromagnetic coil 260 is deenergized (as shown in FIG. 5),
Ball check valve 236 remains open. As a result, each cylinder 198, 200, 202, 20
Piston 27 at 4, 206 and 208
2,274,276,278,280 and 28
2 sequential movements direct hydraulic fluid through passages 210, 21
2, 214, 216, 218 and 220 and into the master cylinder through armature manifold chamber 240 and ducts 284, 286, 2.
88, 290, 292, and 294 create almost no pressure build-up. Chamber 240 acts as a manifold for ducts 284, 286, 288, 290, 292, and 294 and the master cylinders associated with these ducts, respectively. The system remains filled with hydraulic fluid. Because the solid master pistons 272, 274, 276, 278, 28 into the eccentric chamber 104
0 and 282 is compensated for from the supply duct 258. It will be appreciated that a drainage path (not shown) is provided from the eccentric chamber 104 to a hydraulic fluid reservoir (not shown).

However, when electromagnetic coil 260 is energized, armature 254 is attracted to coil 260 against the biasing force of spring 268, resulting in check valve 23
6 is seated on the seat portion 234. Passage 210, 21
2,214,216,218 and 220 are closed, the pistons 272,274,276,27
The sequential movements of ducts 8, 280 and 282 respectively
and 294, sequentially generating pressure pulses in
These pulses determine the engine cylinder number.
6, 2, 4, 1, 5 and 3 to operate the slave piston. It will be appreciated that the precise timing of the pressure pulses depends on the relative positions of drive shaft 86' and eccentric 96. Since shaft 86' is driven at half the engine speed, one
The rotation produces one pulse in each cylinder of the engine when this cylinder is near the end of its compression stroke. If it is desired to vary the timing of the pressure pulses as a function of pressure increase, cam 29
6, the trilobal cam 194 shown in Figures 4A and 4B.
Six leaves of the same shape can be provided. cam 2
The position of 96 is controlled by a piston and coupling that responds to increased pressure as shown in Figures 4A and 4B. In this case, of course, the cam 296 is
6'.

Modified crossheads, such as those disclosed in US Pat. No. 4,399,787 and South African Patent No. 80/7495, may also be used to open the exhaust valve during braking.

Then, with reference to FIGS. 7 and 8, another pulse generator 37 using a positive displacement gear pump
6 will be explained. When applied to an engine with six cylinders, this pulse generator 376 has six teeth and an eccentrically mounted five-tooth gear 378.
An internal gear member 378 is provided which is designed to mesh with the internal gear member 378. Gear 380 is journalled on an eccentric 382 fixed to a shaft 384 that is positively driven at half engine speed. More specifically, a spline ring 386 (FIG. 8) is secured to the shaft 384 and is secured to the shaft by a washer 388 and a cap screw 390. This spline ring 386 engages internal splines formed in an auxiliary drive shaft 392 that is actively driven at half the speed of the engine crankshaft. If other accessories are also to be driven by this auxiliary drive shaft 392, a second spline ring 394 can be secured to the opposite end of the shaft 384.

The main body of the pulse generator includes an adapter plate 396 and a main housing 398 secured to the engine block (not shown) by cap screws 466.
and a rear housing 400. The rear housing 400, internal gear member 378, and main housing 398 are secured together with six cap screws 402 located between the six lobes or roots of the internal gear 378.
An annular groove 404 is formed in the rear housing 400 and communicates with a hydraulic fluid supply duct 408 via a passageway 406. The annular groove 404 has a maximum diameter smaller than a circle tangential to the lobes of the internal gear 378 so that as the external gear 380 rotates within the internal gear 378, the gear 380 traverses the annular groove 404 and allows hydraulic fluid to flow through the annular groove 404. The teeth of gears 378, 380 and housing 398,
400 into a chamber defined by 400 surfaces. The diameter of the annular groove 404 is equal to the chamber 410.
and the point at which the hydraulic fluid can be pressurized. The diameter of annular groove 404 thus defines the location of line 32 in FIG. 2A. Dimensions are groove 40
An annular groove 412 equal to 4 is formed in the housing 398 . O-rings 414, 416 may be installed between internal gear 378 and housing 400, 398 to prevent hydraulic fluid leakage.

A passageway 418 is formed within housing 398 adjacent the root of each of the six teeth of internal gear 378 . Passage 418 is connected to main housing 39
8 and an adapter plate 396 which acts as a manifold for the passage 418 and several chambers 410 of the positive displacement gear pump. Annular manifold chamber 420 may be conveniently sealed using O-rings 422 and 424 located between adapter plate 396 and main housing 398. A plurality of springs 428 seat annular ring valve 426 in a blind hole 430 formed in adapter plate 396 and freely position annular ring valve 426 within annular chamber 420 .
bias toward the housing 398 by.

A passageway 432 communicates between the annular chamber 420 and a ball valve chamber 434 (FIG. 7) that includes a ball valve 436. Passage 438 is connected to ball valve chamber 434
and the supply path 440 are connected. A solenoid valve 442 is attached to the adapter plate 396, and the solenoid valve includes a solenoid coil 444, a core 446, and an armature chamber 45.
Movable iron disk 448 loosely attached within 0
and an armature 448 and a ball valve 43 in the core 446.
6 and a pin 452 installed between the two.

When the electromagnetic coil 444 is energized, the armature 448
moves pin 452 against ball valve 436 so that hydraulic fluid flow from passage 432 to passage 438
and then to the supply path 440.

Further, an outlet duct 4 is provided in communication with each passage 418.
54, which duct extends to a mounting portion 456 within the main housing 398. The mounting portions 456 are connected to the ducts 284, 286, 288, 290, respectively.
Suitable to accommodate 292 and 294 (5th
(Fig.), these ducts are connected to subordinate cylinders respectively associated with cylinders No. 6, 2, 4, 1, 5 and 3 of the engine.

A passageway 45 formed in the bottom of the housing 400
8 communicates with tube 460 and a passageway 464 formed in adapter plate 398 . tube 460
can be conveniently sealed into housing 400 and adapter plate 396 by O-ring 462.

In operation, the rotation of the auxiliary drive shaft 392 is caused by the rotation of the shaft 38.
4 and eccentric 382 to rotate the five-tooth external gear 380 within the six-tooth internal gear 378. Pulses of hydraulic fluid are sequentially provided from each of chambers 410 through passageways 418 into annular chamber 420 . Some of the hydraulic fluid is circulated between chamber 410 and annular manifold chamber 420 via passage 418, while a portion of the hydraulic fluid passes through passages 432 and 438 to supply passage 440 ( (See Figure 7). Fluid that may leak from chamber 410 along axis 384 flows into passageway 458 and returns to the engine hydraulic fluid reservoir via tube 460 and passageway 464.
Since the passage 432 is open when the solenoid valve is deenergized, no significant pressure can be created in the outlet duct 454.

However, when solenoid valve 442 is energized,
Ball valve 436 seals passageway 432 and allows pressure to build up in annular manifold chamber 420. This pressure causes the ring valve 426 to seat in the passageway 418 under low pressure such that a pulse of hydraulic fluid from the chamber 410 flows through the passageway 418 and the outlet duct 45.
4 and pressurize the ducts 284, 286, 288,
290, 292 or 294 and its associated subordinate cylinders. Continuous rotation of the auxiliary drive shaft 392 is achieved through the ducts 284 and 28.
6, 288, 290, 292, and 294 and their associated dependent cylinders. Auxiliary drive shaft 3
92 rotates at half the speed of the engine crankshaft, one hydraulic pulse is generated in ducts 284, 286, 288, 2 during two revolutions of the engine crankshaft.
90, 292 and 294 and their associated subordinate cylinders. Spline ring 3 for auxiliary drive shaft 392
By appropriate adjustment of 86, the pulses can be timed so that each engine exhaust valve opens at a predetermined point near the TDC position of the engine piston at the end of the compression stroke of the associated cylinder. .

Although the above description assumes the use of a six-cylinder engine, the pulse generator described in FIGS. By providing an external gear 380 having one fewer tooth than the number of cylinders in the engine, the present invention can be applied to an engine having an arbitrary number of cylinders.

The pulse generator of FIGS. 7 and 8 includes one chamber 410 for each engine cylinder. If desired, only three chambers can be used in accordance with the subordinate cylinder arrangement shown in FIG. In this case, the outlet 456 of the other chamber 410 could be directed to the supply channel 408 or 440, or the outlet of the other chamber 410 could be used for other purposes. Of course, the pulse generator of FIGS. 7 and 8 could also be designed with one chamber 410 for each pair of engine cylinders. Similarly, the pulse generator of Figure 5 is modified to provide the engine with one master piston for each pair of cylinders, and the pulse generator of Figures 3 and 4 is modified to provide one master piston for each engine cylinder. However, a master piston can also be provided.

Although neither the pressure control mechanism nor the boost timing mechanism is shown in FIGS. 7 and 8, it is understood that either or both of these mechanisms could be used in the embodiment of FIGS. 7 and 8. It will be obvious to business owners.
Pressure control mechanism 1 shown in Figures 4A and 4B
A duct 80, 92 or 94 or duct 2 communicating 50 between the outlet 456 and the slave cylinder.
84, 286, 288, 290 or 294. In order to incorporate the boost timing mechanism into the embodiments of FIGS. 7 and 8, the drive shaft 3
It is necessary to swing the internal gear 378 relative to the rotation angle 84. This is achieved by forming the hole for the cap screw 402 as an arcuate slot, and by providing the hydraulic cylinders 184, 190 and the coupling portion 196 as shown in FIGS. 4A and 4B to connect the gear 378 to the suction manifold. This can be achieved by swinging in response to changes in pressure increase.

[Brief explanation of drawings]

FIG. 1 is a graph of exhaust valve motion during each cycle of engine operation, FIG. 2A is a graph of positive displacement pulse generator displacement as a function of time, and FIG. 2B is a graph of the displacement of the crank drive piston and cylinder. FIG. 3A is a schematic diagram of a positive displacement pulse generator in the form of a positive displacement pulse generator operating at engine speed.
1 is a layout diagram of a decompression engine retarder with a pulse generator of units, each unit suitable for opening the exhaust valves of two cylinders in a six-cylinder engine alternately at the beginning of a braking operation for cylinder No. 6; Fig. 3B is an explanatory diagram showing the mechanism of Fig. 3A in the initial stage of the pulse when the subordinate piston of cylinder No. 1 is seated on the stop portion, and Fig. 3C is an explanatory diagram showing the mechanism of Fig. 3A in the initial stage of the pulse when the subordinate piston of cylinder No. 1 is seated on the stop portion. 3A is an explanatory diagram showing the mechanism of FIG. 3A at the maximum pulse pressure when the exhaust valve No. 6 is opened;
FIG. 3D is an explanatory diagram showing the mechanism of FIG. 3A when the pulse is completed and the subordinate pistons for cylinders No. 1 and 6 have returned to the reset position;
FIG. 3E is an explanatory view showing the mechanism of FIG. 3A at an initial stage in the continuous pulse for cylinders No. 1 and 6 when the subordinate piston of cylinder No. 6 is seated in the stop part, and FIG. FIG. 3G is an explanatory view showing the mechanism of FIG. 3A at the maximum pulse pressure when the dependent piston of No. 1 opens the exhaust valve of cylinder No. 1, and FIG. 3G is an explanatory view of the mechanism of the housing 64 shown in FIGS. It is an enlarged detailed explanatory diagram,
FIG. 4A is an enlarged view of the pulse generator showing details of the structure with the solenoid valve in the deactivated position and the timing advance mechanism in the low boost position, and FIG. 4B is an enlarged view of the pulse generator with the solenoid valve in the energized position and the timing advance mechanism in the high boost position. FIG. 5 is an enlarged view of a pulse generator showing a timing advance mechanism; FIG. 6 is a graph showing the effect of turbocharge boost on exhaust valve timing; and FIG. 7 is a partially cut away end view of another pulse generator using a positive displacement gear pump. 8 is a sectional view taken along line 8-8 in FIG. 7. 10, 12... Curve, 16... Curve, 18... Pump, 20... Shaft, 22... Crank, 24... Connecting rod,
26...Piston, 28...Cylinder, 30...Curve,
32... Line, 34... Engine block, 36... Cylinder, 38... Piston, 40... Cylinder, 42...
Piston, 44...Valve, 46...Spring, 48...Valve, 5
0...Spring, 52...Valve, 54...Spring, 56...Arm, 58...Crosshead, 60...Piston, 62
...Cylinder, 63...Crosshead, 64...Housing, 65...Spring, 66...Valve, 68...Spring, 70
...Arm, 72...Crosshead, 74...Piston, 76...Cylinder, 78...Spring, 80...Duct, 82...Cylinder, 84...Housing, 85...
Pulse generator, 86... Drive shaft, 88, 90... Cylinder, 92, 94... Duct, 96... Eccentric, 97
...Ring, 98,100,102...Piston, 1
04... Eccentric chamber, 106... Passage, 108... Contact part,
110... Stop part, 112... Broken line, 114... Contact part, 116... Stop part, 118... Duct, 120...
Solenoid valve, 122... Solenoid coil, 124... Movable iron disk, 126... Control rod, 128... Ball valve, 1
30... Valve seat, 132... Ball chamber, 134... Valve chamber, 136, 138, 140... Passage, 142... Disk valve, 144... Cylindrical outer shell, 146... Piston, 148... Ring, 150... Pressure control mechanism, 1
52... Housing, 154, 156... Passage, 15
8... Cylindrical chamber, 160... Piston, 162... Spring,
164...cap, 166,168...curve, 17
0... line, 172, 174, 176... point, 178...
Curve, 180... Point, 182... Boss, 184... Hole, 186... Passage, 188... Duct, 190... Piston, 192... Spring, 194... Cam, 196...
Joint, 198, 200, 202, 204, 20
6,208...Cylinder, 210,212,21
6,218,220...Aisle, 222...Chamber,
226…Chamber, 230…Chamber, 234…
Seat portion, 236... Check valve, 238... Spring, 240...
Manifold chamber, 242...chamber, 246...chamber, 250...chamber, 254...movable iron disk, 256...passage, 258...duct, 260...
Coil, 262, 264...Lead, 266...Spring, 268...Core, 270...Control rod, 272,2
74,276,278,280,282...piston, 284,286,288,290,292,
294...Duct, 296...Cam, 376...Pulse generator, 378, 380...Gear, 382...Eccentric, 384...Shaft, 386...Ring, 388...Washer, 390...Screw, 392...Drive shaft, 3
94...Ring, 396...Adapter plate, 398,4
00...Housing, 402...Screw, 404
...Groove, 406...Passage, 408...Duct, 410
...Chamber, 412...Groove, 414,416...O
- ring, 418... passage, 420... annular chamber, 42
2,424...O-ring, 426...valve, 428...
Spring, 430... Hole, 432... Passage, 434... Chamber, 436... Valve, 438... Passage, 440... Supply path, 442... Valve, 444... Coil, 446... Core, 448... Movable iron disk, 450... Chamber, 452... Pin, 454... Duct, 456... Mounting part, 458... Passage, 460... Tube, 462
...O-ring, 464...passage, 466...screw.

Claims (1)

[Scope of Claims] 1. A crankshaft 86, an intake and exhaust manifold, at least one exhaust valve for each cylinder, and at least one slave for opening said exhaust valve in conjunction with a deceleration operation. A decompression engine retarder for use in a multi-cylinder four-stroke internal combustion engine comprising a piston, which is actively driven in synchronization with the engine crankshaft to sequentially duct pulses of hydraulic fluid under pressure to predetermined slave pistons. rotary hydraulic pulse generators 85, 85' supplied by 80, 92, 94;
The ducts 80, 92, 94, 284-294,
Reference numeral 454 interconnects the slave piston and the hydraulic pulse generator, and further includes a common valve control section 120 arranged in relation to the duct, which valve control section 120 is connected to a movable iron plate movable by an electromagnetically actuated valve and the hydraulic pulse generator. a manifold connecting the ducts, when the electromagnetically operated valve is not actuated, the connection of the ducts establishes through the manifold a low pressure fluid condition that occurs during a fuel supply operation in the duct; When the actuation valve is operated during deceleration, the connection of the duct through the manifold is directly or indirectly blocked by another valve actuated through movement of the movable iron plate, so that the connection of the duct through the manifold is directly or indirectly blocked. A decompression engine retarder characterized by establishing high pressure fluid conditions in the decompression engine retarder. 2 The duct has branches 136, 138, 140
or 210, 212, 214, 216, 218,
2. The engine retarder according to claim 1, wherein the engine retarder is connected to the manifold via 220. 3. A patent characterized in that the pressure control means 150 are provided with a chamber communicating with the duct and expandable in response to pressure to limit the maximum pressure produced by the pulse generator to a predetermined level. An engine retarder according to claim 1 or 2. 4. The pressure control means includes a cylinder 152 that communicates with the ducts 80, 92, and 94, a piston 160 that is installed in the cylinder and reciprocates, and that controls the piston against the pressure of the hydraulic fluid in the cylinder and the duct. 4. The engine retarder according to claim 3, further comprising a biasing spring 162. 5. The engine retarder according to claim 3, wherein the pressure control means comprises a Bourdon tube. 6. A rotary hydraulic pulse generator is driven at engine speed and comprises one positive displacement pump member 85 for each pair of engine cylinders, said engine cylinders simultaneously reaching top dead center of the engine. An engine retarder according to claim 1, characterized in that the engine retarder comprises: 7 A rotary hydraulic pulse generator is driven at half engine speed and one for each engine cylinder.
2. The engine retarder of claim 1, further comprising: positive displacement pump members. 8. Each positive displacement pump member includes a first piston 272 reciprocatable within the first cylinder 198 between a first position and a second position, the first position of the first piston being controlled by a pressure regulating means. The pressure regulating means is adjustable in response to the pressure within the intake manifold, and the pressure regulating means is arranged via a rotary cam 194 that cooperates with the first piston 272 to define the first position of the first piston, and a second duct. a second cylinder 182 communicating with the intake manifold;
and a second piston 190 that can reciprocate within the second cylinder 182 in response to pressure in the second cylinder 182 and the intake manifold.
and the second cylinder against the pressure in the second cylinder.
the second cylinder 1 that biases the piston 190;
82 and the second piston 190
and the rotating cam 194.
6. The engine retarder according to claim 6 or 7, characterized in that the engine retarder comprises: 9. Another valve actuated via the movement of said movable iron plate consists of a disc valve 142 movable in said manifold 134 connecting the duct between a first position and a second position, and one of said positions. 10. In claim 1, wherein said disc valve prevents interconnection of said ducts, but in other of said positions allows said ducts to be interconnected through said manifold to a drain. 8th
Engine retarder as described in section. 10 Rotary hydraulic pulse generator driven at half engine speed and internal gear 378
a positive displacement gear pump having a positive displacement gear pump, the internal gear meshing with an external gear 380 having a number of teeth or lobes equal to the number of cylinders in a multi-cylinder engine; a number of positive displacement pump chambers 410 equal to the number of cylinders in said multi-cylinder engine with one fewer tooth than
2. The engine retarder of claim 1, wherein said duct interconnects each positive displacement pump chamber and a slave piston. 11 the other valve comprises a ring valve 448 movable within the manifold 450 between a first position and a second position, the ring valve 448 preventing interconnection of the ducts in the first position; 11. The engine retarder of claim 10, wherein, in its second position, each of the ducts can be interconnected through the manifold to a drain.