US2914054A - Fuel injection timing apparatus - Google Patents

Description

2 Sheets-Sheet 1 H. DEUTSCHMANN FUEL INJECTION TIMING APPARATUS Nov. 24, 1959 Filed April 7', 1958 A INVENTOR. 'HERBERT oEuTscHMANN du@ *my ATToRNEY D ID i In

...wImHIH Nov. 24, 1959 FUEL Filed April '7, 1958 H. DEUTSCHMANN INJECTION TIMING APPARATUS 2 Sheets-Sheet 2 INVENTOR.

HERBERT DEUTSCHMANN ATTORNEYS United States Patent() FUEL INJECTION TIMING APPARATUS Herbert Deutschmann, Stuttgart-Bad Cannstatt, Germany, assgnor to Daimler-Benz Aktiengesellschaft, Stuttgart-Untereturkheim, Germany.

This invention relates to an apparatus for adjusting the timing of fuel injection for an internal combustion engine and in particular for a reversible engine in which the fuel injection timing is automatically adjusted in response to changes both in engine speed and direction of rotation.

One of the objects of this invention is to provide an improved fuel injection timing device for` an internal combustion engine of the above type. l

Another object of this invention is to provide an improved hydraulically operated fuel injection control device, more specifically a device of this type using oil from the engine lubricating system for actuation thereof.

Another object of this invention is to provide anV improved device of the above-mentioned type which uses oil pressure from the engine lubricating system for at least partially actuating the device.

Still another object of this invention is to provide an improved hydraulic control system for a device of the above-mentioned type, more particularly a hydraulic control system including means responsive to engine speed for controlling the system.

A further object `of this invention is to provide a simplied fuel injection control device Vthat is easily adjusted automatically for proper timing of fuel injection for engine rotation in both directions at various speeds.

The invention relates to a device for the adjustment of the beginning of injection for internal combustion engines with fuel injection which are reversible for righthand or left-hand rotation and especially those usedfor driving ships and locomotives. `The device responds to the rotative engine speed and, by means of `flyweights workjection for various speeds in both directions of engine rotation.

The invention purports to attain an automatic adjustment of the most suitable beginning of injection with simple means and without rebuilding of reversible internal combustion'engnes, which without reverse gears are of small weight and used for driving of ships. The invention comprises for right-hand rotation as well as left-hand rotation a pair of flyweights, each pair cooperating with a slide valve. Both valves control the ilow of oil delivered by a reversible oil pump, in dependence on the rotative engine speed and direction, to actuate a piston in a cylinder. For right-hand engine rotation, the piston is movedV in one direction for an axial adjustment and setting of the driveshaft of the injection pump from a later to an earlier beginning of injection, and for left-hand engine rotation the piston is 2 moved in the other direction for axial adjustment and setting from a later to an earlier beginning of injection.

The control arrangement can be made so that .the slide valves cooperating with the flyweights are arranged coaxially with each other and enclose a valve-adjusting piston therebetween which, in dependence on the oil pressure acting on the piston in the cylinder and controlled by one slide valve for one direction of engine rotation; brings the other slide valve, which controls the oil pressure in the other direction of rotation, outof contact with the yweights `that cooperate therewith so as to be inoperable thereby.

According to another feature of the invention for operation of the internal combustion engine in one direction, the `oil delivered at one pressure by the pump for the movement of the pistonv inthe cylinder in one axial direction may be advantageously controlled by one slide valve, andthe other slide valve controls, at the same time, the admission of oil at a smaller pressure into the cylinder for effecting a restoring force which acts against the adjusting force on the piston and vice versa. f

ln the pressurized oil circuits which effect the adjusting force and the smaller restoring force, the delivery lines, the control openings and the discharge lines may advantageously have functions depending on direction of engine rotation whereby the operation of the system may be readily reversed. i

The oil pump which furnishes oil under pressure `for adjusting the force on the piston may be connected to the pressurized lubricating oil circuit of the internal combustion engine.

The oil pump suction and discharge chambers, which are'alternately interchanged in their Vfunctions depending on the direction of engine rotation, may each be provided with an inlet valve and an outlet valve, preferably ball valves not spring loaded, to `prevent reverse flow at each valve. 4

Furthermore, the inlet or supply valves for both pump chambers may be connected to a common supply conduit while the outlet valves of the respective pump chambers may, however, bearranged in independent discharge lines through one ofwhich, depending on the direction of rotation of the oil pump, ows oil for effecting the adjusting force and through the other is delivered `oil of thel pressure -of thelubrication oil system for effecting the 'restoring force. '.-Adv'antageously, both pressure oil circuits for the adjustingdevice may be conducted thereto in an axial direction at opposite sides thereof.

In the preferred embodiment of the invention, the main adjusting piston and the centrifugally actuated control valvestherefor are rotatable With the driving shaft of the fuel injection `pump and the cylinder which encloses the piston and valve means.

The foregoing and other objects, features and advantages of the present invention will become more obvious fromthe following description when taken in connection with the accompanying drawing, which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

Figure l is a longitudinal section through a -fuel injection timing device with a reversible gear pump connected thereto and shown in a larger scale; and

,Figure 2 is a partial section of the control device of Figure l with some of the control elements in different operating positions.

Inside a housingl, a hollowr shaft 2, which in fourcycle internal combustion engines rotates at half the crankshaft speed, is supported in bearings 3, 4 and is not axially slidable. ABetween the bearings 3, 4 the hollow shaft 2 forms a cylinder 5 -in which is arranged a disk-shaped piston 6 which divides the cylinder into two v`ruimten Nov. 24, 1959A 3 chambers 7, 8. The piston 6 is solidly connected with a tubular shaft 9 and both are slidable in the hollow shaft 2.

,.Inside thetubular shaft 9,axiallynslidable valves 10, 11 are arrangedto enclose betweevnthemanaxially slidablevvalve-djustiiig piston 12. The slide valves 10, 11 arel provided at their outer circumference with annular grooves 13 and 14, n respectively, and have axially directed .lbloreiholes 15 and 16, respectively. The slide valvs'l10 ,11 are connected with the abutment members 23 and 24, respectively, which are slidably arranged on the hollow shaft 2, ,by means of bolts 17 and A18 which extend respectively transverselythrough therslide valves, longitudinal grooves `19;V and 42 0l inthe tubular shaft 9, and longitudinal grooves 21 and 22 inthe hollow shaft 2.,'.4 The abutment members 2324usupportends of controlfcompression springsr25jand 26respecti'vely, which in turn are positivel`y'J supportedat theirmother ends on the hollow shaft 2. Y When the; control is inactive, springs 25 and 26 act through Athe abutmentsy2`3 and 24 to move bothrvalvles 10 and 11.l against piston 12. In the range Vof the longitudinalA grooves 2,1` and 22',dresp ect,ive`ly, bore holes 27 and 28, respectively are Aprovided in the `abutment members 23 and 24lrespectively. Levers 29 of llyweights 30 abut against theabutment member 23 and ear pivotally mounted onone `end of the cylinder 5. Levers 31 of lllyweigihts v32 abut against the abutment member 24 andare pivotally mounted on the other end of the cylinder 5K. e e Y Y An oil pump 33, which is preferably arrangedY inside the housing 1, is a gear pump having gears 34, 35 and suction and discharge chambers 36, 37 which are inter- 0changeable in operation. A vcommon oil delivery line 3S leads to these chambers from the pressure lubricating sys- -tern of the internal combustion engine, which, for instance, supplies the bearings of the crankshaft. In the path of delivery from line 38, ball check valves 39, 40, which are not .spring loaded, are arranged ahead of the chambers 36, 37, respectively. l l

The chambers 36 and 37 discharge respectively through independentlines 41, 4 2 which have in their respective paths , ballz'check valves 43, 44,` which also are not spring loaded.i ,The ball valves 43, 44 are arranged above the ball valves 39,140, and there exists a directcommunication between the ball valve 39 land the ball valve 43 and between the ball .valve 40 and the ball valveN 44, The discharge .line 41 leads through bearing 3, the hollow shaft 2 and the tubular shaft `9 to a chamber 45 in shaft ,9Maxially ahead ofthe slide valve 10, whereas the discharge line 42 leads through a bearing cover 46 to` a amber 47 in shaft 2 axially in front of the slide valve l right-hand'rotation of the internal combustion engine, the gear 34 of the pressure oil pump 33 is driven in the direction of arrow 48 in Figure l. At the same time, the hollow shaft 2 is rotatably driven by the crankshaft-driven'gear 49 in one direction along with the cylinder 5, Vthetubular shaft 9, the lpiston 6, the slide valves 1t), 11 and the valveadjusting piston 12. y

:I'he piston 6, until a mean speed of rotation of perhaps IOQQ r.p.m. lis reached remain iirst of all in apposition, as shown in Figure ,1, in which the driveI shaft 55 of an injection pump (not shown) `is rotatably adjusted relative to gear 49 for a late beginning of injection Aby axial adjustment of the tubular shaft 9 and shaft 51, which is,Y connected vto an axial extension of shaft 9 guided inside the hollovvfshaft 2, to shift helical grooves 52 on shaft Slaxally relative corresponding cooperating grooves in a bearingmember 53 of the gear 49. The axial splines 52 'of the shaft 51 are slidrable'inrternallysplined shaft 55;

,Theloil which "branches v' )lf fi'o'1n thelubricating oil system having a pressure of, Yfor instance, two atmospher'es (2 kg./c"m.2) is delivered, for rightLhand rotation through lthe delivery lin'e`3'8 pastthe ball valve 40`into the chamber 37 which acts as suction chamber. From there the oil is delivered at a higher pressure by the gears 34, 35 to the chamber 36, which is effective as the discharge chamber, and past the ball valve 43 through the discharge line 41 to the bearing 3 and'into the chamber 45. From the chamber 45, the oil having a pressure of approximately 10 atmospheres (10 kg./cm.2) is lead through the bore 15 in the slide valve 10 and pushes the piston 12 to the right which in turn pushes the slide valve 11 in the same direction so that it compresses the control spring 26 by means of the bolt 18 and the abutment 24. r

When pushed to the right, as seen in Figure 1, the slide valve 11 at least partially uncovers an annular groove 57 in thetubular s haft 9 from which bores 58 through the piston 6 lead to the chamber 7 in the cylinder 5. In this way, oil, which is furnished the oil pump 33 through the supply line 38 and which has passed to discharge line 42 through the ball valve 40`as Well as the ball valve 44, is delivered to the chamber 7 of the cylinder 5 by way of discharge line 42, chamber 47, bore 16 in the slide valve 11, annular groove 57 and the bore hole 58. Each of the end faces of piston 12 are provided with transversely cut slots or grooves so as not block the bores V15 or 16 when the piston abuts valves 10 or 11, respectively.

Until the engine speeds up, oil pressure in chamber 7 holds the piston 6 in the extreme right position as shown in Figure l. With increasing engine speed, the centrifugally operated yweights 30 a'c't on abutment 23 through levers 29 and overcome the effect of the control spring 25, whereby the slide valve 10 is moved toward the left along with the abutment 23 and the bolt 17. Thus, the slide valve l10 uncovers the annular groove 59 in the tubular shaft 9 so that the oil in the chamber 45 of approximately l0 atmospheres pressure (l0 kg./cm.2) ows into groove 59 and then into the chamber 8 of the cylinder 5 through bore holes 60 in piston 6. Inasmuch as the pressure in chamber 8 is larger than in the chamber 7, the piston 6 is moved in response to increasing engine speed to the left to a position corresponding to the de'ection of the flyweight's 30. When the yweights 30 and 32 Vrotate at low speeds, those weights not restrained by abutments 23 and 24 may swing outwardly as indicated for 32 in Figure 1 and for 30 in Figure 2.

In moving to the left, piston 6 and tubular shaft 9 move the shaft 51 axially so that the 'drive shaft 55 of the injection pump is rotatably adjusted relative to the gear 49 to 'advance the start of fuel injection for each cycle of engine operation. The relative angular rotation of ge'ar 49 and shaft 55 is produced by means of helical grooves 52 oirth'e shaft and corresponding internal helicalgrooves' in the rotatable bearing member 53 conn'e'cted to gear 49. AAs indicated lin the drawings, the shaft 51 is axially s'lidable in'the injection pump drive shaft 55.

iAs the engine speed fluctuates, the radial position of the weights 30 will vary andaccordingly adjust the axial position of valve 10, which in turn effects adjustment of the piston 6 and drive shaft 55 to adjust the -fuel injection timing.

When the internal combustion engine is reversed from a right-hand rotation to left-hand rotation, as for instance by an axial movement of the camshaft to engage a new set of cams, vthe gear v34 in the pressure oil pump rotates in -the direction opposite arrow 48. The chamber 36 becomes the'suction chamber whilerchamber 37 becomes the pressure chamber. Oil at approximately l0 atmospheres (l0 kg./cm.2) is delivered by the pressure oil pump 33 through its pressure chamber 37, and passes the ball valve 44, through the discharge line 42, into the chamber 47 and then through bore 16'to move piston 12 to the left. Accordin'gly, the slide valve 1Q is also moved to the left, as'shown in Figure 2, uncovering groove 59.

The pressure "oil which owsthrough Vthe supply line 38 at a pressure the same as exists in the lubricating oil system of the internal combustion engine, for instance, 2 atmospheres (2 kg./cm.2), passes Ythe ball valve 39 and ball valve 43 and flows through discharge line 41, vcharnber 45, bore 15, groove 59 and through the bore 60 in the piston 6 into the chamber 8 of the cylinder 5. The piston' 6 is thereby held in a position as shown in Figure 2 in which, for left-hand rotation, the beginning of injection is retarded.

Thereafter, for controlling the timing of fuel injection for left-hand operation, the yweights 32 act'on abutment 24 to shift valve 11 axially, controlling admission of oil to chamber 7 and accordingly'determining axial displacement of piston 6 and shaft 9. Inasmuch as with increasing speed, for instance above 1000 revolutions per minute, the iiyweights 32 overcome the effect of the control spring 26, the slide valve 11 allows delivery of oil through groove 57 and the bores 58 in the piston 6 to the chamber 7 of the cylinder 5. The piston 6 and tubular shaft 9 are thereby moved to the right along with the shaftSl so that a relative angular rotation of the drive shaft 55 in relation to the gear 49, corresponding to an advance or earlier beginning of injection, is produ'ced through the helical grooves 52 and the correspondingly formed bearing member 53 of the gear 49.

The oil returning from the chambers 7, 8 of the cylinder 5 flows into the slide valves 10, 11 through the bores 58, 60, the annular grooves 13, 14 through the longitudinal grooves 19, 20, 21, 22 in the hollow shafts 9, 2 and through the bore holes 27, 28 in the abutments 23, 24 into the housing 1 and the oil sump of the internal combustion engine. lf necessary, suitable means may be provided to limit the oil pressure in lines 41 and 42 to valuesadequate to operate the device as described without damage-thereto, any excessV pressure being preferably relieved to the interior of housing 1.

By the described arrangement, the reversing of an internal combustion engine from a right-hand operation to left-hand operation and vice versa may be done without any additional manipulations for setting of the timing or beginning of injection which is automatically controlled by control springs and centrifugal means in a man ner dependent on the speed and direction of rotation.

In order that the two end positions of the piston 6 correctly set the beginning of injection equally before top dead center at maximum engine speeds for righthand as well -as left-hand rotation, it is advantageous to form the cams which are arranged on the drive shaft of the injection pump for the operation of the pump plungers as symmetric cams in such a manner that the beginning of delivery in one direction of rotation repeats itself in the opposite direction of rotation after rotation through an angle referred to as the symmetry angle of the beginning of delivery and, in a four-cycle engine, equal to one half of the following computation:

360, minus angle of delivery before top dead center at maximum rotative speed, minus angle of delivery before top dead center at minimum rotative speed, minus tooth clearance of the fuel pump drive in degrees of crank.

The above-described apparatus is especially adaptable for lreversible four-stroke cycle engines in which the working stroke for one direction of rotation corresponds to the compression stroke of the opposite direction of rotation.

While I have shown and described one embodiment in accordance with the present invention, it isl understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit of the present invention, and I intend to cover all such changes and modifications as encompassed in the appended claims.

I claim:

1. A device for adjusting the timing of fuel injection for a reversible internal combustion engine comprising a cylinder, a piston slidable in said cylinder, hydraulic means including pump means for applying uid under pressure to opposite sides of said piston, a shaft member movable axially by said piston, a driven member adjusted by axial movement of said shaft member for controlling the timing of fuel injection during engine operation, valve means for controlling the application of fluid pressure to opposite sides of said piston to move the latter, and weights centrifugally actuated in response to engine speed for automatically operating said valve means to correspondingly adjust the fuel injection timing for rotation of said engine at different speeds in either direction, said shaft being axially movable in one direction to advance the fuel injection for one direction of engine rotation and being 'axially movable in the opposite direction to advance the fuel injection for rotation of the engine in the opposite direction.

2. A device according to claim 1, wherein the cylinder, piston, valve means, shaft and weights are rotated at a speed dependent on engine speed and further including helically grooved members for coupling said shaft to an engine crankshaft, said grooved members being relatively rotatably adjusted by axial displacement of said shaft.

3. A device for adjusting the timing of fuel injection for a reversible internal combustion engine comprising a cylinder, a piston slidable in said cylinder, hydraulic means including Vpump means for applying uid under pressure to opposite sides of said piston, a shaft member movable axially by said piston, a driven member adjusted by axial movement of said shaft member for controlling the timing of fuel injection during engine operation, valve means forA controlling the 'application of uid pressure to opposite sides of said piston to move the latter, and weights centrifugally actuated in response to engine speed for automatically operating said valve means to correspondingly adjust the fuel injection timing for rotation of said engine at different speeds in either direction, said shaft being axially movable in one direction to advance the fuel injection for one direction of engine rotation and being axially movable in the opposite direction to advance the fuel injection for rotation of the engine in the opposite direction, said cylinder, piston, valve means, shaft and weights being rotated at a speed dependent on engine speed and further including helically grooved members for coupling said shaft to an engine crankshaft, said grooved members being relatively rotatably adjusted by axial displacement of said shaft, said valve means comprising a separate valve for controlling displacement of the piston for each direction of engine rotation, each of said valves having a separate centrifugally actuated valve operating weight, said pump means comprising a reversible pump having its direction of rotation dependent on the direction of engine rotation, and means responsive to the direction o f rotation of said pump for rendering one or the other of said valves, respectively, inoperable by its associated weight.

4r. A device for adjusting the timing of fuel injection for a reversible internal combustion engine comprising a cylinder, a piston slidable in said cylinder, hydraulic means including pump means for applying fluid under pressure to opposite sides of said piston, Aa shaft member movable axially by said piston, a driven member adjusted by axial movement of said shaft member for controlling the timing of fuel injection during engine operation, valve means for controlling the application of liuid pressure to opposite sides of said piston to` move the latter, and weights centrifugally actuated in response to engine speed for automatically operating said valve means to correspondingly adjust the fuel injection timing for rotation of said engine at different speeds in either direction, said shaft being axially movable in one direction to advance the fuel injection for one direction of engine rotation and being axially movable in the opposite direction to advance the fuel injection for rotation of the engine in the opposite direction, said cylinder, piston, valve means,

7 shaft and weights being-rotated at a speed dependent on engine speed and further including helically grooved members for coupling 'said Shaft to an engine crankshaft, said grooved members being relatively rotatably adjusted by axial displacement of said shaft, said valve means cornprising a separate valve for controlling displacement of the piston in response to the engine speed for each direction of engine rotation, said pump means including a reversible pump, the pumping direction of which is dependent on direction of engine rotation, and means responsive to the direction of pumping of the pump for rendering one or the other o f said valves, respectively, inactive with regard to control of piston position for different engine speeds.

5. A device according to claim 4, wherein said lastmentioned means includes a second -piston engageable with both said valves and movable in response to uid pressure from said pump.

6. A device according to claim 5, wherein said valves and the second piston are slidable in a tubular structure fixed to the first-mentioned piston.

7. A device according to claim 4, wherein said valves are coaxially and slidably arranged and wherein the pump delivers oil at one pressure to actuate the piston in one direction, the oil delivery being controlled by one of the valves while Vthe other valve simultaneously admits loil at lower pressure to the opposite side of the piston when the engine is rotating in one direction and wherein for rotation of 'the engine in the opposite direction the relationship of oil pressures and the controlling action of the valves is reversed.

8. A device according to claim 4, wherein oil conduits are connected between said pump and said valves and wherein for one direction of engine rotation'one conduit carries oil to one valve at one pressure and another con- 'which furnishes 'oil for adjusting the piston is connected to a lubricating oil system of the internal combustion engine Which is also under pressure.

10. A device according to claim 8, wherein the oil pump comprises two chambers which may be alternately interchanged as suction and pressure'charnbers depending from the direction of rotation of the engine, each chamber being provided with inlet and outlet check valves.'

11. A device `according 'to claim 10, wherein said check valves are ball valves, unbiased except by gravity and oil pressure.

12. A device according to claim 10, wherein the inlet valves for each of the pump 'chambers are connected in common to an engine vlubricating system supply while the other valves of each pump chamber are connected to independent discharge lines, one of said lines carrying oil at the pressure of the engine lubricating system and the other line carrying oil from the pump at a higher pressure when the engine rotates in one direction, the pressure relationships i'n said lines being reversed for engine rotation in the opposite direction.

13. A device according to claim 12, wherein said independent discharge lines are connected to deliver oil axially at opposite sides of said piston.

References Cited in the le of this patent UNITED STATES PATENTS

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