US 2444440 A
Description (OCR text may contain errors)
J l 6, 1943, a GR l ESHAB ER aim.
fIuTErhiAL-oimsnbu' ENGINE Filed 'se t. 27, 1946 3 Sha na-Sheet 3,
I Fien- Fig.6
Patented July 6, i948 INTERNAL-COMBUSTION ENGINE Emil Grieshaber and Karl v. Anderson,.Milwaukee, Wia, assignors to Nordberg Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application September 27, 1946, Serial No. 699,697
9 Claims. (Cl. 123-90) This invention relates to the control of two cycle engines in which the cylinders fire serially. The best example of such an engine is the radial single crank type which will be used as the basis of explanation of the principles involved. An'
eleven cylinder engine is illustrated but the scheme can be used with an engine having any odd number of cylinders per crank from three cylinders up.
Control is effected by variation of the fuel sup ply in two ranges one above, and the other-below an intermediate value which will be loosely called halfload." In the upper range all cylinders fire serially in each revolution of the crank so that the firing order is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. In
the lower range the engine operates on the two cycle principle, but alternate cycles for each cylinder are suppressed. Thus, in two revolutions of the crank, the firing order is 1, 3, 5, 7, 9, 11, 2, 4, 6, 8, 10. This will be recognized as a typical 4- cycle firing order for single crank radial engines.
The result is bad by arranging the fluid distribution ports uniformly around a fixed sleeve in the order 1, 3, 5, 7, 9, 11, 2, 4, 6, 8, 10, i. e. all the odd numbers in order, then all the even numbers in order. Turning in the sleeve at half crankshaft speed is a rotor which is shiitable axially to cause one or the other oi two director pom to coact with the distribution ports One director port has one outlet, but the other has two which are diametrically opposed. The latter engages all the distribution ports serially in one half turn of the rotor (i. e, in one turn of the crank), but the former requires a full turn of the rotor (i. 'e. two
turns of the crank) and so gives the firing order' described above as a typical four stroke firing order.
Theoretically such a distributor could be used to deliver-fuel directly to the various cylinders,
but since the connection to the cylinders would ordinarily be oblectionably long, each cylinder is fed by a corresponding normally closed pressure opened valve, and the distributor admits motive fluid serially to the pressure motors of the valves and then exhausts it therefrom.
A further refinement involves the use of gas as a fuel and as the motive fluid for actuating the valves. The gas is delivered at high pressure say 100 p. s. i. and is supplied to the pressure actuated valves for admission to the engine cylinders at a reduced pressure say 50 p. s. i. The distributor directs high pressure gas to the motor units of the valves and exhausts the motor units into the low pressure gas line. This scheme offers the advantage that it any valve actuating motor should leak, the leaking gas will flow to the low pressure line and thus be'fed to the engine.
The forms of the director ports and distribution 1 From idling speed to half load the engine operates on the described 4 cycle firing order (1. e. omits alternate 2 stroke cycles for each cylinder) the duration of opening of the gas valves progressing from minimum to maximum. At half load the sleeve shifts rapidly sufl'iciently to establish the normal two stroke firing order, but with minimum duration of opening. From here on to full load, the duration of opening of the gas valves progresses to maximum.
In the following discussion no attempt will be made to describe the details of the crank-connecting rod arrangement which is preferably that described and claimed in the application of Karl V. Anderson, Serial No. 692,982, filed August 26,
1946. It shouldbe understood that any crank arrangement suited to a single crank radial engine can be used.
The gas inlet valve in Figure 8 of the present application is not claimed per se in the present application, but forms the subject matter of appllcants' pending application Serial No. 699,698, nled September 27, 1946.
In the accompanyin drawings,
Fig, 1 is a general plan view of the engine intended chiefly to indicate the distributor, the cylinders and the connections from the distributor to the inlet valve motors of the various cylinders. Secondary details are omitted.
Fig. 2 is a view, principally in elevation, of the distributor and the control connection from the governor andfrom a manually adjustable controller. The latter is set in full operating position. In this view parts are broken away to show the drive from the crank-shaft to the distributor.
Fig. 3 is a vertical section through the distributor on a relatively large scale. The'line of section is indicated at 3-3 on Fig. 4. The rotary valve is in its lowermost position assumed when and at the right side of the distributor tioned in Fig. 5. I
Fig. 8 is an axial section of one of the pressure operated fuel gas inlet valves.
Fig. 9 is a fragmentary section on the line 9-9 of Fig. 5.
As best indicated ir Figs. 1 and 2, the engine h'as a crank-case I l with cover l2. On the crankcase are mounted eleven cylinders designatedas Ci, C2, C3 and so on to CH. In each of these cylinders is an ordinary trunk piston (not shown) each operatively connected by a connecting rod to a single crank on the vertical crank shaft 13. The shaft l3 turns clockwise when viewed in plan and the normal firing order is CI, C2, C3 CI I. 1
The crank and rod arrangement is preferably that shown in the copending application identifled above.
The distributor which is the distinctive feature of the present invention is driven by a shaft M which turns at half crank shaft speed in the opposite direction to that of the crank shaft l3 (1. e., counter-clockwise when viewed in plan). Shaft I4 is driven by pinion I5 on the upper end of shaft l3, the pinion meshing with gear i6 fixed on shaft l4 and forming a two to one reduction train.
Shaft I4 is mounted in a spider H which carries two bearings I8. A bonnet I9 is mounted on the rim of spider I1 and supports a fixed cylindrically bored bushing which serves as the distributor valve seat 2!. This is ported in a manner to be described in detail. Bolts 22 hold the bonnet and spider to the crank-case cover I2 (see Figs. 2 and 3). Valve seat bushing 2! seats on flange 23 and is positioned by stake 24. Housing 25 held by bolts 23 engages its upper end and as posiholds it fixed in bonnet [9. The valve seat bushing 2i makes a gas-tight fit with bonnet i9 at the circumferential zones 21, 28 and 29 and is relieved in the intermediate spaces to afford gas passages.
Shaft i4 is coaxial with the bore of valve seat 2| and carries at its upper end a hub 3i splined at 32 to a hollow cylindrical distributor valve 33, so that the valve 33 may be shifted axially but always turns with hub 3| and shaft US.
The valve is shifted axially by a governor-controlled rocker 34 fulcrumed at 35 in housing 25. A link 36 connects rocker 34 with the inner race of an annular ball bearing 31, whose outer race is clamped in the upper end of valve 33 by the annular plug 38 threaded into the upper end of valve 33. A spacer 39 holds oil guards as shown in Fig. 3.
The valve 33 has end portions 4i and 42 which fit the bore of seat 2i and between these are two circumferential lands 43 and 44 (see Figs. 5-7). Sealing rings 45 are mounted in grooves in the end portions 4i and 42. The lands 43 and 44 fit the bore of valve seat 2i but have no sealing rings. Intermediate portions of the exterior of valve 33 are reduced in diameter, except for two'diametrically opposed rectangular bosses 46 and 41 which fit the valve seat.
Boss 46 has two triangular recesses 48 and 49 connected by groove 5| at the trailing edge. Boss 41 has a single triangular recess 52 diametrically opposed to 49 and at the same distance from the lower end of valve 33. All recesses 48, 43 andp52 space between lands 43 and 44, which as willbe explained is supplied with fuel gas at high pressure (say 100 lbs.). The space between land 44 are connected by passages 53 and 54 with the Q and the lower end 42 is at a lower gas pressure (say 50 lbs.)
To supply gas at high pressure to the interval between lands 43 and 44 a connection 55 leads from thehigh pressure gas supply line through bonnet l9 to port 53 in bushing 2|. A connection 51 leads from port 58 in bushing 2! to a point in the low pressure gas line which feeds the inlet valves, later described.
The groove between land 43 and end portion 4| is a leakage collecting groove, which is connected by passage 50 and ports 63 with the low pressure gas space below land 44. Thus leakage is recovered and fed to the fuel valves.
Throughout this specification and in the drawings the numeral 55 will be used to signify a connection to the high pressure gas line and 5'! a connection to the low pressure gas line.
A circumferential series of eleven ports 59 are uniformly spaced around bushing 2! in position to be engaged by recess 48 or by recesses 49 and 52 depending on the axial displacement of valve 33. In the position shown in Fig. 3 there is no engagement. If the valve 33 is raised slightly recess 48 alone would engage ports 59 and at the upper narrow end thereof causing the cylinders to fire serially once in two revolutions of the crankshaft. As the valve is raised further, the lower wider end would engage. Further raising will cause the upper narrow ends of 49 and 52 to engage causing the cylinders to fire serially once in each revolution of the crank shaft, and the period of engagement will increase if the valve is raised further.
The ports 59 correspond to the various cylinders Ci to Cll respectively, to which they are connected by connections 'Bi to Bil. The arrangement of these is shown in Figs. 1 and 4. They do not run serially but run through odd and then even ordinals successively in a closed circular series. It should be observed that since the crank-shaft and the distributor rotate in opposite directions, the fact is reflected in a reverse order arrangement clearly indicated in Figs. 1 and 4.
The connections BI to Bil do not supply fuel gas to the cylinders. tive pressure fluid (fuel gas at lbs.) to pressure motors which operate the inlet valves of the various cylinders. These motor operated valves. are generally indicated by the numeral 6i and the construction of the valves is shown in Fig. 8. The actuating connecting lines which lead from Bi, B2, etc., as the case may be, are numbered 32 for all cylinders, and lead as diagrammed in Fi 1.
Each motor operated valve 6| has a body 63 which fits into a recess formed in the corresponding cylinder casting and extends across a gas passage 64 connected to the low pressure gas line. Body 53 has a seat 65 for the inlet valve 66 which has a stem 61 and controls fiow of fuel gas from passage 54 to and through an aperture 63 which communicates with the working space of the cylinder. A piston 69 encircles stem 6'! and works in a cylinder in body 63. A spring seat bushing H is confined between a shoulder 12 in stem 67 and the piston 69. A nut 13 with check-nut, both threaded on the end of valve stem 31, hold the parts in assembled relation. The valve isbiased closed by a coil compression spring 14.
To limit the opening movement of the valve an adjustable stop bushing 15 is threaded into the upper end of body 63 and has an inturned flange 16 which is engaged at the limit of open- Instead they deliver moing movement by an encircling flange formed on piston- 49 for that P p se. The assembly at 'l'l is a clamp to lock bushing in its adjusted position. An internal seal cap 19 is threaded into the interior of bushing 15 and an external seal cap 18 is threaded onto the exterior thereof.
The connection 62 leads to the enclosed space above piston 89. The connection 8| receives another branch of the low pressure gas line andis simply a convenient way of venting gas if it leaks downward past piston 59. The swiv'eled part 82 is not concerned with the normal functioning of the valve. and need not be here described.
A speed responsive governor" (see Fig. 2) is driven by crank-shaft lLthrough gear 84. Its
construction is known. It includes a swinging arm 85 which turns clockwise on rise of speed, and is connected by link 88 with the short arm of a bellcrank lever 81 whose long arm is hinged to link 88. Link 88 and the long arm of bellcrank 81 are equal in length. The other end of link 88 is hinged to radius rod 99 and-to one end of a link'9l whose other end is hinged to arm 92 fast on a shaft 93. :Iournaled in housing 25.
Fast on shaft 98 is a cam 94 which has two complementary portions respectively engaging rollers 95 and 98 on rocker 84. The form of cam 94 is such that as cam 94 is turned counterclockwise rocker 94 is tilted clockwise, lifting sleeve 83.
. 6 uniform firing characteristics below as well as above half load. It greatly extends the range of satisfactory control.
Obviously the simplest and most practical arrangement isto use a fixed valve seat and locate the valve within the seat. Hence this arrangement is'descrlbed for illustrative purposes. It should be remembered, however, that so far as the broad principle of the invention is concerned the essentials are a valve anda seat with provision for relative rotation and relative axial displacement between the two for the purposes set forth. Hence. the description of a fixed valve seat and a valve which may rotate and shift axially is intended to be illustrative and not limiting.
Guide link 89 swings about a pivot 91 adjustmaximum fuel position shown in Fig. 2, and a stop position in which the hinge 99 between links 88 and 9| is coaxial with the fulcrumof bellcrank 81. In the stop position the governor exercises no control and the valve 33 is in its lowermost position as shown in Fig. 3.
The greater slope in cam 94 at IN is provided to accelerate the tilt of rocker 34 at the so-called half load position. a
It should be observed thatsince the space between end rim 42 and land 44 is at the lower gas pressure any port 59 and its connected motor is exhausted except when the port is lapped by one of the bosses 46 or 41. Thus the timing of the commencement of venting of lines 52 is not affected by the governor, but the pressure built up in the line, and hence in the related valve motor is affected by the duration of engagement of the recess 48, 49 or 52 as the case may be with each port 59. This is controlled by the governor,
and does affect the opening'of each valve 55 iii extent and duration of opening, since flow out through any line 62 cannot be instantaneous.
Consideration of Figs. 3 to 7 will show that when only cavity 49 engages ports 59 it will take one turn of the valve 83, or two turns of the crank-shaft for all cylinders to receive charges. The order of feeding the branches is Bl, B3, B5, B1, B9, Bl I, B2, B4, B5, B8, Blll (seeFig. 4, remembering that 33 turns counter-clockwise). If the two cavities 49 and 52 engage ports 59 all cylinders will fire in one half turn of the distributor or one turn of the crank-shaft. To demonstrate, if 49 charges BI, 52 will next charge B2, 49 charges B3. 52 charges B4, and so on to charge all cylinders in one-half, turn of the distributor; after What is claimed is:
1. The combination of an internal combustion engine having a crankshaft and an odd number of cylinders arranged to fire serially on a two stroke .cycle; means for supplying fuel to said cylinders; a cylindrical distributor valve seat having an annular series of ports related to said fuel supply means to control the operation thereof; a distributor valve coacting with said seat and rotatable relatively thereto, said valve being shiftable relatively to the seat in an axial direction and having two sets of director ports which are caused selectively to coact with the annular series of seat ports by said relative axial shifting of the valve, one set comprising a single director port, and the other two director ports which are 3. The combination defined in claim 1 in which the ports in said seat and distributor are so coordinated as to form, that axial shifting of'thevalve relatively to the seat varies the duration of communication of the director ports with the seat ports, in the same sense and in two ranges, in one of which the single director port and in the other of which the two diametrically opposed director ports coact with the seat ports, and the control means is arranged to accelerate the axial motion of the valve at the point of transition lietween the two ranges.
4. The, combination defined in claim 1 in which the engine is of the radial, single-crank type, the portsin said seat and distributor are so coordinated as to form, that axial shifting of the valve relatively to the seat varies the duration of communication of the director ports with the seat ports, in the same sense and in two ranges, in one of whichthe single director port' and in the other of which the two diametrically: opposed director ports coact with the seat ports, and the control means is arranged to accelerate the axial motion of the valve at the point of transition between the two ranges.
5. The combination defined in claim 1-in which the means for supplyingfuel to the cylinders comprise pressure-motor-operated inlet valves.
Alternative arrangements within the scope of the claims are possible and are con-' 6. The combination defined in claim 1 in which fuel gas is supplied to the engine through two pressure lines, a high pressure line and a low pressure line, the means for supplying fuel to the cylinders comprise p'ressure-motonoperated inlet valves, one for each cylinder, each valve being yieldingly biased in a closing direction and arranged to control the flow of gas from the low pressure line to a corresponding cylinder, the distributor valve seat ports being connected with respective valve motors, and the distributor valve serving to, connect the valve motors alternately to the high pressure line and the low pressure line. 1
7. The combination defined in claim 1 in which the ports in said seat and distributor are so ,ordinated as to form, that. axial shifting of the valve relatively to the seat varies the duration of communication of the director ports with the seat ports, in the same sense and in two ranges, in one of which the single director port and in the other of which the two diametrically opposed director ports coact with the seat ports, and the control means comprises a governor responsive to engine speed and connected to shift said distributor valve through both said ranges.
8. The combination defined in claim 1 in which the ports in said seat and distributor are 50 coordinated as to form, that axial shifting of the valve relatively to the seat varies the duration of communication of the director ports with the seat ports, inthe same senseand in two ranges, in one of which the single director port and in the other of which the two diametrically opposed.
director ports coact with the seat ports, and the control means comprises a governor responsive to engine speed, a variable motion-ratio connection between said governor and said distributor valve whereby the governor acts to shift the valve axially, and manually adjustable means for determining the motion ratio between the gov ernor and the distributor valve.
9. The combination defined in claim 1 in which a the ports in said seat and distributor are so coordinated as to form, that axial shifting of the valve relatively to the seat varies the duration of communication of the director ports with the seat ports, in the same sense and in two ranges, in one of which the single director port and in the other of which the two diametrically opposed director ports coact with the seat ports, and the control means comprises a governor responsive to engine Speed, a variable motion-ratio linkage forming the operative connection through which the governor shifts the distributor valve axially, said linkage being adjustable progressively between a stop position in which the valve is in a no load position regardless of the position of the governor, and a. maximum fuel position in which the governor exercises complete control of the axial position oi. the valve, and manually operengine is in operation.
EMIL GRIESHABER. KARL V. ANDERSON.