US1967538A - Starting and reversing mechanism for internal combustion engines - Google Patents

Description

M 24, 1934. J. ROMEYN 67, STARTING AND REVERSING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Oct. 3. 1951 4 Sheets-Sheet '1 \NVENTOR JEAN ROMEYN ATM/W15."

July 234, 19341- J. ROMEYN 1,967,538

STARTING AND REVERSING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Oct. 5, 1951 4 Sheets-Sheet 2 \NVENTOH J EAN ROMEY N By 4Q) m c/r z ATTOANEY M 24, 1934. J. ROMEYN 1,967,538

STARTING AND REVERSING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Oct. 3; 1931 4 Sheets-Sheet 3 \NVENTOR J EAN ROMEVN ATTORNEY July 24, 1934. RQMEYN 1,967,538

STARTING AND REVERSING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Oct. 5, 1931 4 Sheets-Sheet 4 26 INVENTOR J EAN R OM E! N ATTv/PNEY Patented July 24, 1934 PATENT OFFICE STARTING AND REVERSING MECHANISM FOR INTERNAL COMBUSTION ENGINES Jean Romeyn, Brussels, Belgium.

Application octcb'cis, 1931, Serial No. 566,765 In Great Britain October 22, 1930 3 Claims. (01. 60-16) This invention relates to starting and reversing mechanisms for internal combustion engines using liquid fuel.

When the starting and reversing mechanism comprises, as is well known, a plurality of timed air starting valves arranged in whatever position and check valves fitted to the cylinders and connected by pipes with the timed valves, reversing cannot be readily effected with the arrangements existing heretofore. The operator, after having brought the mechanism into the stop position, must wait until the engine actually comes to rest before starting it in the reverse direction, and under the circumstances, the delay thus caused may be very important. If an attempt is made to move the hand control immediately from the forward position into the reverse starting position, there will be a period during which the engine will still be running in a forward direction, while the compressed air cam gear is timed for rearward movement. Consequently, air will be admitted during the upward stroke of the piston and a pressure equal to the starting air pressure will be reached rapidly. The check valve will thus close and the air entrapped will be compressed to a pressure which may be considerably in excess of the maximum of the normal running cycle. Nevertheless, if the braking action exerted by the air thus compressed by the piston is not sufficient to bring the engine to rest before the top dead center is reached, this braking action is completely lost since the air expands during the following down stroke.

It is the object of the present invention to improve the starting and reversing arrangement wherein each cylinder is provided with a timed air starting valve and an air check valve fltted to the cylinder head, so as to eliminate the drawback referred to above.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings, wherein:

Figure 1 shows a reversing mechanism according to the present invention.

Figure 2 shows a detail of Figure 1.

Figure 3 is a section on line III-III of Figure 1.

' Figures 4, 5, 6, 7 and 8 represent more diagrammatically the mechanism, respectively: in the stop position but for another angular position of the 60 starting cams for the forward and for the rearward movement than that in Figure 1; in the position for forward movement after stopping; in the position for forward movement after rearward movement; in the position for rearward move- 55 ment after stopping after rearward movement;

and in the position for rearward movement after stopping after forward movement.

Figures 9, 10, 11, 12 and 13 are views of details in the direction of arrow 56, respectively, of Figures 4, 5, 6, 7 and 8.

Figure 14 represents diagrammatically the mechanism in the normal running position.

In Figure 1, 1 indicates a manually operated control shaft in the stop position. It is brought into the position for starting for forward movement by turning it by means of hand lever 48 in an anti-clockwise direction through 90 and into a starting position for rearward rotation by turning it in a clockwise direction through 90. An eccentric 2 is mounted on the shaft 1 and engages with a fork at the end of a lever 3 of which the other end is pivotally connected to a collar 4. This collar is mounted in a groove of a sleeve 5 which is slidably mounted on a cam shaft 6, but is prevented from rotating independently of the latter by a key 7. The cam shaft 6 is connected to the engine crank shaft (not shown) so as to carry out one revolution for each revolution of the crank shaft, when the engine operates on the two stroke cycle, or a half revolution foreach revolution of the crank shaft when the engine is a four stroke cycle engine. The sleeve 5 carries a cam 8 which is the starting cam for forward movement. The starting cam 9 for rearward movement is formed at the end of a lever 10 of which the other end is pivoted at 11 to the sleeve 5. At the middle the lever 10 engages between two collars 12 secured to the cam shaft 6.

A number of starting air valves 13, one for each cylinder, are arranged with their spindles parallel to the cam shaft 6 in a circle having its centre coincident with the centre line of the cam shaft 6. Two of these valves are visible in the sectional drawings (Fig. 1). These valves are mounted in a valve chest 14 supplied 'with compressed air through a pipe 15. when no air is admitted into the valve chest each valve is held in the open position by a spring 16, each of the springs being coiled around a tappet 17 having a rounded head 18. When a suitable air pressure has been built up in the valve chest 14, the valve stems are forced downwards against the pressure of the springs 16. Each starting valve, when opened, allows air to pass through pipe 49 into the chamber 19 of a corresponding check valve 20. The check valve chambers are mounted on the cylinders heads 50. The valves 20 are controlledby springs 21. A cylinder 22 is fitted to each chamber 19 and a piston 23 slidably mounted in this cylinder opens the valve 20 against the action of the spring 21 when compressed airis admitted through apipe 24.

0n the control shaft 1 are mounted two cams 25 and 30. The cam 25 serves to open the main air valve 26 provided in a valve chest 27 and normally held in the closed position by a spring 28, when the control shaft is turned through 90 in either direction. A pipe 29 connects the valve chest 27 to a compressed air tank 51 so that when the valve 28 is opened compressed air. can pass through the pipe 15 into the valve chest 14. The cam 30 lifts one end of a pivotally mounted lever 31 in the stop position. This lever is connected at its other end by a rod 32 to the fuel pumps in such a manner that the pumps are stopped when the lever is in the position illustrated and supply more and more fuel as the end of the lever gradually moves to the lower portion of the cam surface which is the case when turning the shaft 1 in either direction from the position shown.

The particular construction of the fuel pumps is immaterial. But in order that the working of the mechanism be more readily understood, a group of fuel pumps designated by 52 is shown diagrammatically on the drawings. The construction of fuel pumps of the general type employed to'carry out the present invention is shown in British patents, Nos. 152,757 and 261,598. Generally, the actual delivery of such pumps depends upon the position of some member, such as lever 53 actuated by the rod 32.

The variations of the rate of flow of the pumps are effected by example as follows: To lever 53, which pivots about 53a, is connected an arm 60, the end of which engages in the cross-head 61a of a plunger 61. This cross-head 61a is urged by a spring 62 against a cam 63, the rotation of which is controlled by a motor shaft. The pumps comprise an intake valve 64 loaded by a spring 65, a delivery valve 66 loaded by a spring 67, a liquid return valve 68 loaded by a spring 69, as well as a rod 70 loaded by a spring 71 and pressing on the arm 60. The intake conduit is indicated by numeral 72, the discharge conduit by 73 and the injector by 74.

The different members of the pumps are arranged in such a manner that when the lever 53 is'in the position represented by plain lines and designated 1, the pumps are not producing a flow. is due to the fact that the stem or rod 70 raises the valve 68 while the piston 61 is raised by the cam 63. The parts of the pumps are also disposed in such a manner that when the lever 53 is in the position represented by dotted lines and designated II, the pumps operate to produce their maximum rate of flow. This is due to the fact that for this position of the lever 53, the rod 70, which is removed from the valve under the action of spring 71, will no longer contact with the valve during the raising of piston 61. From the preceding, it may be understood that when the lever 53 is between the positions I and ,II, the pumps set up a flow of more or less liquid.

In the position illustrated, the lever 31 holds a small pilot valve 54 01! its seat through the medium of a small plunger 33. The valve is normally held against its seat by a spring 34 and is located in a valve chest 35. Air under pressure may be admitted into the valve chest through a pipe 36. When the valve is opened a small hole provided in the centre of the plunger '83 is closed by the valve 54 and compressed air passes into a pipe 37 to which the pipes 24 from all the cylinders 22 are connected. When the end of the lever 31 moves on to the lower portion of the 30 the 6, 7 and 8 which show clearly valve 54 is closed, whilst the passage in the plunger 33 is subsequently opened so as to release the air pressure in the cylinders 22 thus enabling the check valves 20 to'close. The lever 31 is also connected by a rod 38 to a slide 40 carrying a roller 39 and movable in a guide. The roller'39 cooperates with a cam 41 formed in two parts which are mounted on the sleeve 5. Figure 2 is a plan view of the cam 41 of Figure 1. The cam' 41 moves laterally with the sleeve 5 and by reason of the friction set up by the spring 42 coiled around the sleeve 43, whichls slidably connected to the sleeve 5 by a key 44, the cam 41 tends to turn with the sleeve; A fixed pin 45 (Figures 1 and 2) engaging in a slot in the cam 41 prevents the latter I from turning beyorid a predetermined angle. When the sleeve 5 is in-its uppermost position a projection 46 on the cam 41 is in the path of the roller 39, whilst when the sleeve 5 is in its lower position a projection 47 on the cam 41 is in the path of the roller 39. i

The operation of the mechanism as above described is as follows:

When the shaft 1 is in the position illustrated, which is the stop position, the cam 30' prevents the fuel pumps from operating and holds the pilot valve 54 away from its seat so that all the check valve cylinders 22 are in communication with pipe 15. The main air valve 26 is closed so that no air pressure exists in the valve chest 14 105 nor in cylinders 22. All the valves 13 are therefore in the open position and the cams 8 and 9 are out of engagement with the tappets 18.

The various parts of the mechanism are represented more diagrammatically on Figures 4, 5, 110

the working of the device.

Figure 4 corresponds to Figure 1 as regards the position of the different parts, exceptthat the sleeve 5 is shown in another angular position so that the shape and the relative position of cams 8 and 9 may be readily visible.

The angular position of sleeve 5 in these figures corresponds to the top dead center for the power cylinder to which the particular valve 13 represented is connected.

Figures 9, 10, 11, 12 and 13 are side views of cam 41 and roller 39 in the direction of arrow 56, showing the respective position of these parts.

Assuming that-the cam shaft 6 is rotated in the direction of the arrow 55 when the engine is running forwardly and assuming that the engine has been running forwardly before being stopped, the cam 41 wfll be in such an angular position that the projection 47 is in line with the roller 39 (Figure 9).

If the control shaft 1 is turned into the position for forward operation (see Figures 5 and 10) the end of the lever 31 in contact with the cam 30 will drop on to the lower portion of the cam 30 whilst the sleeve 5 is raised. This dropping movement is caused by a spring 80 pulling on the arm 31. By reason of the upward movement of the sleeve 5 the projection 47 of the cam 41 is moved out of the pathof the roller 39 movement of the lever 31 is not prevented. The fuel pumps are thus brought into a position for operation, no air pressure is built up in the cylinders 22 and the check valves 20 remain closed.

At the end of the movement of the shaft 1 the 145 main air valve 26 is; opened and the valves 13 closed with the exception of the one of which the tappet 17 is stopped by the starting cam 8 for forward movement Compressed air is admitted into the corresponding cylinder through the check 5.

so that valve and consequently the engine is started. All the starting valves are then operated in succession by the cam for forward movement.

Figure shows clearly that cam 8 will lift the 6 valve 13 represented (and afterwards'the other valves 13 in succession), but that cam 9 is inoperative.

The starting air pressure used with the mechanism described should preferably be lower than the compression pressure.

Thus when ignition takes place in the cylinders the check valves 20 will no longer open except for a short period of time during expansion. By turning the shaft 1 into a position between the starting position and the stop position as represented in Figure 14 the main air valve 26 is closed and the speed of the engine can be controlled as desired as the cam 30 is provided on both sides of the projection thereon with two gradual slopes enabling the lever 31 to be brought into a position in which the pumps do not deliver their maximum amount of fuel, whilst the pilot valve 54 is still closed.

If it is now assumed (see Figures 6 and 11) that the shaft 1 is brought from the stop 'pOSition into the position for forward movement as previously, but the engine has previously been running rearwardly or is still running rearwardly (as shown by arrow 57) by reason of the inertia of the fly wheel and the reaction exerted on the propeller, the cam 41 will be brought into a position in which its projection 46 is in the path of the roller 39 so that this roller can no longer move towards the left. The starting cam for forward movement will thus be brought into operation, whilst the pumps are stopped and the check valves opened.

The cam 8 does no more open each valve 13 at the top dead center and close it somewhere during the expansion stroke, as before, since the engine is yet running rearwardly (arrow 5'1), but it opens the valve while the piston is going upwards and closes it at the top dead center. If the check valve was free at all times, as is the case in the arrangements known heretofore, it would close as soon as the air admitted into the cylinder reaches the pressure of the air receiver, and thereafter this air would be compressed up to the top dead center which would submit the engine to stresses considerably in excess to those which are normally developed. After the top dead center the air would expand again, so that no braking action would be obtained.

But, with the arrangement shown, the air can be transferred back into the air receiver via the check valve 20, the corresponding va1ve.13 and the air valve 26; the power developed by the expansion of the air left in the cylinder, after the top dead center, is much less than the power necessary to drive the greatestpart of the air back into the air receiver, and consequently the engine is rapidly brought to rest and thereupon starts in the opposed direction (arrow 55). Immediately, the cam 41 turns and comes again into the position shown in Figure 10. Thus, the lever 31 is no longer prevented from occupying the position shown in Figure 5. The valve 54 is closed, air pressure in cylinders 22 is released, the check valves become free to close, and the fuel pumps deliver fuel (lever 53 in position II). From this moment, the engine is started forward as explained before.

It will be seen that when bringing the shaft 1 from the stop position into the starting position for rearward movement (Figures '7, 8, 12 and 13) the same sequence of operations takes place except that the cam 9 operates the valves 13 instead of the cam 8. The pumps will come into operation immediately and the check valves will be free from the start (Figures '7 and 12) if'the previous direction of rotation was for rearward movement (arrow 57) but the projection 4'1 will stop movement of the roller 39 (Figures 8 and 13) until the engine actually commences to rotate for rearward movement if the previous direction of rotation was forwardly or is still forwardly (arrow 55) due to inertia.

What I claim is:

1. In a reversing multi-cylinder internal combustion engine comprising means for injecting liquid fuel in the cylinders, a starting and reversing mechanism consisting of a starting valve for each cylinder, a starting cam for forward movement adapted for operating the starting valves, a starting cam for rearward movement adapted for operating the starting valves, a check valve for each starting valve mounted directly on the cylinder heads of each cylinder, pipes for connecting each starting valve to the corresponding check valve, fuel pumps, a hand-controlled mechanism adapted, on the one hand, for varying the position of the cams relatively to the starting valves in such a manner that, according to its position, the starting valves are operated by one or the other of the starting cams or by none, and, on the other hand, for simultaneously opening the check valves and rendering the fuel pumps inoperative when it is placed in its stop position, a member urged by the motor so as to maintain the check valves opened and the fuel pumps inoperative, whenever the hand-controlled mechanism is brought into the forward position and the engine continues to rotate rearwardly or the hand-controlled mechanism is brought into the rear position and the engine continues to rotate forwardly, means for urging the said member to turn with the engine, means for preventing the said member from turning beyond a predetermined angle such that when it has turned from this angle it no longer maintains the check valves in the open position and the fuel pumps inoperative, means for constantly urging the check valves towards their seats, and means for constantly urging the fuel pumps towards their operative position.

2. In a reversing multi-cylinder internal combustion engine comprising means for injecting liquid fuel in the cylinders, a starting and reversing mechanism consisting of a starting valve for each cylinder, a starting cam for forward movement adapted for operating the starting valves. a starting cam for rearward movemev adapted for operating the starting valves, a check valve for each starting valve mounted directly on the cylinder heads of each cylinder, pipes for connecting each starting valve to the corresponding check valve, fuel pumps, a hand-controlled mechanism adapted for varying the position of the cams relatively to the starting valves in such a manner that, according to its position, the starting valves are operated by one or the other of the starting cams or by none, a cam actuated by the said hand-controlled mechanism, a pivoted lever one arm of which rests in contact with the said last cam, a positive connection between the said pivoted lever and the fuel pumps adapted for rendering the fuel pumps inoperative when the said hand-controlled mechanism is in its stop position, a compressed air pilot valve, a spring constantly urging the latter towards its seat, a

, check valves, cylinders containing these pistons,

springs constantly urgingsaid pistons so as to put the check valves on their seats, ducts leading air from the other side of the pilot valve on the pistons connected to the check valves so as to lift the latter from their seats, a shaft rotating with the engine, a sleeve slidably mounted on said shaft and rotating with the latter, a connection between this sleeve and the hand-controlled mechanism adapted to shift the sleeve axially when the said hand-controlled mechanism is displaced for varying the position of the cams relatively to the starting valves, a cam loosely mounted on the said sleeve, a friction drive between this sleeve and this cam,- a stop for this cam preventing the latter from rotating without certainlimits, a roller cooperating with the cam, and a slide carrying this roller and connected to the pivoted lever, the said cam being provided with two bosses arranged in two different planes and in two difierent angular positions so that either of them prevents the roller from returning to the position in which the check valves are released and the fuel pumps put into operation,

-whenever the hand-controlled mechanism is brought into the forward position and the engine continues to rotate rearwardly or the handcontrolled mechanism is brought into the rear position and the engine continues to rotate forwardly. v

3. In a reversing multi'cylinder internal combustion engine comprising means for injecting liquid fuel in the cylinders, a starting and'reversing mechanism consisting of a starting valve for mouse for forward movement in such a manner that the starting valves may be actuated in turn by the cam for forward movement, a lever pivoted at one end of the sleeve, a cam for rearward movement mounted on the other end of this lever,

a pivoting connection between this lever and the said cam-shaft such that the sliding movement of the sleeve brings the first cam out of engagement and tilts the lever so as to bring the second cam into the operative position a check valve for each starting valve mounted directly on the cylinder heads, pipes for connecting each starting valve to the corresponding check valve, fuel pumps, a hand-controlled mechanism adapted,

on the one hand. for shifting the sleeve and so varying the position of the cams relatively to the starting valves in such a manner that, according to its position, the starting valves are operated by one or the other of the starting cams or by none, and. on the other hand, for simultaneously opening the check valves and rendering the fuel pumps inoperative when it is placed in its stop position, a member urged by the motor so as to maintain the check valves opened and the fuel pumps inoperative whenever the hand-controlled mechanism is brought into the forward position and the engine continues to rotate rearwardly or the hand-controlled mechanism is brought into the rear position and the engine continues to rotate forwardly, means for urging the said member to turn with the engine,. means for preventing the said member from turning beyond a predetermined angle such that when it has turned from this angle it no longer maintains the check valves in the open position and the fuel pumps inoperative, means for constantly urging the check valves toward their seats, and means for. constantly urging the fuel pumps towards their operative position.

1 JEAN ROMEYN.

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