US2713800A

US2713800A - Device for controlling internal combustion engine drive

Info

Publication number: US2713800A
Application number: US188198A
Authority: US
Inventors: Hans J M Forster
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1949-10-05
Filing date: 1950-10-03
Publication date: 1955-07-26
Anticipated expiration: 1972-07-26

Description

26, 5 H. J. M. F'ciRs-rER 2,713,800

DEVICE FOR CONTROLLING INTERNAL COMBUSTION ENGINE DRIVE Filed Oct. 5 1950 3 Sheets-Sheet l TAIL/613,701! $49: 54575: 4 MW v G July 26, 1955 H. J. M. F'cSRsTER DEVICE FOR CQNTROLLING INTERNAL COMBUSTION ENGINE DRIVE Filed Oct. 5, 1950 3 Sheets-Sheet 2 Ml-CLLM QM July 26, 1955 I v H. J. M. FbRSTER 2,713,800

DEVICE FOR CONTROLLING INTERNAL COMBUSTION ENGINE DRIVE Filed Oct. 3, 1950 3 Sheets-Sheet 3 m m 1 121 I29 131i 3 111' 115 11 1 111 I56 117 I30 15/ I]! If! 7.13 133 1.71

n J J 11 1 J 172' 170 728 7619 Fig.5

-LA/I/ENTDIQ f/nr/s Fauesnse 6/: #a z. A. I

United States Patent DEVICE FfiR ONTRQLLING INTERNAL COlVIBUSTIONENGINE BRIVE Hans J. M. Forster, Harthausen A. F., Kr. Esslingen (Neckar),.Germany, assignor to Daimier-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany AppiicationOctoberS, 1950, Serial No. 188,198 Claims priority, appiication Germany Qctober 5, 1949 17 Claims. ((11. 74-472) efiicient, and especially suitable control mechanism for the operation of the machine, particularly a motor vehicle, primarily in a manner enabling the driver to obtain an accurately predetermined control of the output of the power plant'by adjusting a single device.

The invention provides more particularly a control which renders the shifting of gears or changing of the gear ratio dependent upon the speed of the driven shaft of the transmission, that is, dependent upon road speed, with a simultaneous control by throttling the power output of the engine.

An important object of the invention is to combine different possibilitiesof control and to simplify and im prove the automatic shift, in such a manner that for each respective shift level, adjustable at the will of the driver, maximum power output of the engine is utilized and peak efficiency of operation is obtained simultaneously therewith.

Accordingly, an essential feature of the invention consists in controlling the drive so that, at least within the range of several of the upper gear positions or ratios, the power output of the engine, at all speeds of the driven shaft, that -is, at all road speeds, is essentially constant, assumes only a slightly inclined, for example, alternately rising and falling course within relatively small power limits, with the power output level being adjustable at willor preselectable.

A further object of the invention resides in the provision of a control system for drives of thedescribed character wherein the element which affects the engine power is controlled by one or more factors determining the power of the engine (for example, engine speed, charge or the like), and wherein the associated gear shifting assembly is not only shifted dependent upon the driving speed, engine speed, oranother corresponding value, but also dependent upon the existing or selected power output of the engine, the pressure at the narrowest point of the carburetor Venturi tube, or of a Pitot tube or the like being employed as an especially suitable measure of function of the engine power to be used in controlling the latter.

Another object of the invention resides in the provision of an arrangement in which, with increasing speed of the driven shaft of the transmission, the prime mover is operated, within each of the several gear conditions, alternately first unthrottled or essentially unthrottled and then with gradually increased throttling up to the shift to the next higher gear, so that for each gear condition a certain initial increase in power occurs corresponding to the power curve, and then a decrease in power takes place in turn prior to the shift to the next higher gear condition or ratio.

2,713,800 Patented July 25, 1955 A further object of the invention resides inproviding a control arrangement for obtaining uniform power output of the engine at a preselected power level, without special reaction on the part of the operator to accommodate himself to the resistance or load on the driven shaft of the machine by utilizing the pressure below atmospheric at the narrowest point of the carburetor Venturi tube as an engine control factor which changes, within the range considered to be suitable for operation of the vehicle, nearly proportional to the power output of the engine, with a minor drop with increasing engine speed.

A further objectof the invention is to provide control mechanism which, when applied to automatically shifting transmissions, efiects the shift from one gear .to another gear automatically at predetermined throttle position of the engine, without substantial drop of power from the adjusted or selected power level during the interval of the shift and likewise .during operation .within an engaged gear position and the acceleration of the vehicle takes a steady course and the ,shift of the transmission from lower to higher gears is accomplished practically imperceptibly for the driver and occupants of the car while the demanded power of the engine is fully utilized and peak efficiency of operation is obtained, and wherein the control mechanism effects automatic adjustments of the drive in response to changing road resistance, for example, in hilly teritory, in an especially advantageous manner, so that, decreasing road speed, corresponding to increasing road resistance, results ina certain power increase at the same time.

Still another object is to provide control mechanism having the above characteristics and adapting the selection of the gears to the total road resistance, so that-it is possible for the machine to run-at least undernormal circumstances--in nearly unthrottled condition, as soon as the vehicle has reached its maximum speed, 'determined by the road resistance, in high gear (for example, overdrive) and this maybe so even if the operating member which adjusts the power level is adjusted to part-load only. 7

Still another object is to provide control mechanism having the above characteristics and which when the preselected powerlevel is suddenly increased, effects a return shift to the next lower gear ratio, and when 'the power level'is suddenly decreased, then a shift to the'next higher gear takes place, in the first case provision may be made for a suitable perceptible resistance, and in the second case for a suitable retarding device.

A still further object is to prevent the engine noise from surpassing the road noise in the lower gear'sta'ges, provision beingmade in the latter for a premature shift to the next higher gear deviating from the previously described control, and furthermore, the return shift from higher to lower gear may suitably take place at a lower speed of the driven shaft than that at which the up-shift takes place.

Finally, another'objectis to provide for the employment of the engine as a brake in the control as embodied in the invention.

In accordance with the present invention, the above objects are accomplished by providing a control device which comprises an output regulator by means of which output regulator and automatic shiftgear are, for example, linked to a mutual operating member (for 'example, a foot pedal) which can be adjusted by the driver, while regulation of the power output is accomplished, for example, by means of an adjustable feeler mechanism such as a diaphragm case responsive to the pressure below atmospheric in the carburetor venturi throat and subject to overriding control by the operator to adjust the power level. This feeler in turn adjusts a sliding control valve for an auxiliary force which controls the power output of the machine. This auxiliary force actuates, for example, depending upon the position of the control valve, a piston or the like which opens or closes the output regulator of the prime mover (for example, a throttle valve in the air intake of the engine).

The above and other objects, features and advantages of the present invention will be apparent in the a following description of illustrative embodiments thereof, which description is to be read in connection with the accompanying drawings, and the invention consists in the mode of operation, combinations of elements and details of construction appearing in the description and drawings and defined in the appended claims.

In the drawings: Fig. 1 is a shift diagram of a known automatic shift control,

Fig. 2 is a shift diagram for an automatic shift control embodying the present invention,

Fig. 3 is a schematic layout illustrating a power output regulation and shift control embodying the features of the invention.

Fig. 4 is a schematic layout showing the details of a shift device included in the embodiment of the invention illustrated by Fig. 3, and

Fig. 5 is a schematic layout similar to that shown in Fig. 3, but applied to an arrangement for using the engine as braking power.

In the diagrams, Fig. l and Fig. 2, the-loads on the engine for five different gear ratios of an associated transmission are plotted against the road speed v. The fully drawn out curves I to V are the power output curves at unthrottled operation of the engine (that is, with fullyopen throttle in case of a carburetor engine). The fifth speed or gear ratio is used as overdrive or overgear. The total resistance of the vehicle composed primarily of road resistance and air resistance is represented, by way of example for normal conditions on level roads, by the curve W.

Fig. 1 shows a hitherto usual mode of shift control for an automatic gear shift. The shift is accomplished in response to certain road speeds at fully-open throttle and normal operating position, for example, from first to .1

second gear at a road speed of via, from second to third gear at v23, from third to fourth gear at 1 34. and from fourth to fifth gear at 1/45. The power will, with rising road speed, at first rise on the power output curve I for the first gear ratio up to point b1, at which the automatic shift to second gear takes place. Then the power suddenly drops down to value (12, and hereuponlikewise at open throttleascends 011 the power output curve II for the second gear ratio up to point b2, whereupon the shift to point as for the third gear takes place at road speed we. The further power course is in corresponding manner represented by the serrated curve a3b3a4b4a5bw The point bw represents the point of equilibrium between full throttle power output of engine in overdrive and total resistance corresponding to curve W.

If the vehicle, instead of being driven with wide-open throttle, is driven under lesser power demand, that is, with partially-open throttle only, then the power delivered during acceleration from standstill up to a point of equilibrium has correspondingly lowered values, for example, by the points on the dotted curves I0, Ho etc., which define the serrated curve Obo1-ao2boz etc.

By shifting into low operating position the road speeds at which the shift from one gear ratio to the next takes place at the lower gears can (in the known modes of shifting) be transferred to higher values, by way of example for the shift from first to second gear to the higher value we, and for the shift from second to third gear to the higher value v23. The course of power at open throttle is in this case represented by the serrated curve Ob1-a2-b2-a3. A further shift to higher gear speeds is generally not provided for within this range of operation.

The shift method or pattern described in connection with Fig. 1 has the disadvantage that a sharp power drop takes place at every shift, which results in a correspondingly unsteady acceleration curve for the vehicle and likewise in lower efficiency.

According to another one of the hitherto proposed modes of shift control, the shift takes place at the precise moment or speed at which the power curve for the respective gear position or gear ratio and respective throttle position, intersects the full-load or full throttle curve for the immediately following gear position, that is, by way of example, at partially-open throttle, at the intersection point of the curve In with curve II. However, since the throttle is only partially opened, in this case a corresponding power drop also takes place from the power on curve 10, at the point of intersection with the curve II to the power on curve H0 at the same road speed as said point of intersection, provided that the operator does not happen to operate the vehicle with wide-open throttle at the precise moment at which the shift is made.

As distinguished from the hereinbefore described systems, Fig. 2 represents a method of shift control, proposed in accordance with the invention. The driver preselects by way of example any desired power level for the engine, for example, a power output level N, N or N". The output control of the engine is so adjusted that the engine runs with wide-open throttle as long as a further regulation impulse will not be given. When the machine is put in operation and the power level N has been set by the driver, then the power output of the engine rises with increasing road speed and at wide-open throttle up to point B1 corresponding to the speed v1 on the curve I. At this point a feeler mechanism, which has been set to value N by the driver, begins to act, in response to further increasing road or engine speed, on the throttle valve of the engine to adjust the latter towards its closed position. If an accurate and acutely responsive feeler mechanism is available, then it is possible to achieve the closing of the throttle valve in each case only so far that the power level N remains constant through the whole range of shift control, hence, the power curve would run exactly horizontal from point B up to point B2 on curve II at which point the shift from first to second gear takes place and the throttle valve at the time of such shift is restored to wideopen position. The course of power would then occur on the horizontal line N from E2 via B3, B4, B5 etc. up to the intersection point of horizontal line N and curve W, so that the shift control is effective to change the gear ratios without any loss of power from the selected power output level.

However, in practice it will usually be more suitable to use a feeler mechanism acting in a slightly different mannor. in the embodiment according to Fig. 3, the pressure below atmospheric or vacuum at the throat of the carburetor venturi is used as the power-dependent value.

Within the control range to be considered this pressure below atmospheric is sufiiciently proportional to the power output of the engine to make it useful for the desired method of controi. Numeral l in Fig. 3 represents the control member which is manipulated by the operator, and which is connected to a linkage 2 for reciprocating the latter to control, by means of a lever 3, a feeler mechanism. The feeler mechanism includes a diaphragm case or ancroid 4, connected to the lever 3 and to a control valve 5. The linkage 2 is also connected,

'15 or through a line 16 to the topside 17 of the piston 15, depending upon the position ofthe valve 5. The side of the piston 15 which at any time is not supplied with oil is communicated through either line 13 or line 16 past the control valve 5 with the chambers 18 and 19 respectively, which open to atmospheric pressure. The throttle plate 29 in the air intake 21 of the engine is operated by the piston 15. Besides shift lever 1 the road speed of the vehicle also acts uponthe automatic shiftgear 7, for example, by way of a mechanical or hydraulic linkage 22, in such a manner that an adjustment of the lever 1 toward the left and an increase in road speed oppositely affect the automatic shiftgear 7. Then, dependent upon the magnitudes of the opposite effects of the manipulation of control lever 1 and of the road speed, the shift from one gear ratio to another takes place as indicated schematically at 23. The shift, for example, can be effected by a control valve (seen in Fig. 4) which, under the effect of a spring which is to be drawn taut by the lever 1 and under the effect of a pressure of a fluid which changes with the road speed, adjusts itself to a respective position of equilibrium. A similar effect is, for example, obtainable through a compensating lever, not shown, to whose three points of application are connected lever 6, linkage 1:2 and control member 23 which eifects the shift of the gears.

Further, provision may be made for a lever 24 or the like, as schematically indicated, which, as the foot lever 1 is released, positively closes the throttle 2G in order to provide a positive control within the range of pressures of less than atmospheric. in such a case a spring loaded device 25 can be interposed in the linkage which connects the piston 15 with the throttle plate. A manually adjustable lever with a spring loaded stop 26 may serve for limiting the travel of the operating lever 1. The stop can be adjusted by the operator, before starting or while driving, to a position defining an upper power limit which appears to be suitable to him. The operators foot may then rest on the lever 1 to move the latter against the Spring loaded stop and the driver is induced to attain economical fuel consumption, because he can only change to higher power and eventually less economical fuel consumption by overcoming the spring resistance of the stop. The mode of action of the described device is as follows:

In Fig. 3 the no-load position of lever 1 is indicated at x0, the full-load position x1 and the position for the engine brake as. The lever being in an intermediate position x, for example, corresponding to the adjusted power level N of Fig. 2. When the vehicle is just being set in motion from a standstill, the control housing 8 is still under atmospheric pressure, and the aneroid 4 is contracted to raise the control valve 5 to its highest position corresponding to position x of the lever 1. Even during this initial movement of the vehicle, the line 12 is supplied with fluid under pressure and the same flows through the open line 13 into the chamber 14 below the piston 15 and builds up a pressure whereby the piston 15 is moved upwardly into the position shown on the drawing and the throttle valve 2i -being released by the lever 24is moved into wide-open position. With increasing road and engine speed the pressure below atmospheric at the narrowest point it) of the carburetor venturi decreases, that is, the vacuum becomes greater, and this pressure decrease is communicated to the chamber 8. The aneroid 4 expands to move the control valve 5 downwards. However, initial downward movement of the 6 valve ,5 does not cause any change in the flow through the

lines

13 and 16 and the throttle valve is not yet affected. Consequently, the power output ascends from point along the curve I (Fig. 2).

When the road speed v1 is attained, the pressure below atmospheric at point 16, and hence in the housing .8, is down to a value and the control valve has executed a certain downward stroke of predetermined length, line 13 will be closed by the control valve 5 and line 16 connected with the control chamber 11 instead. At this instant, the piston 15 begins to move downward and to close the throttle valve 20. As a necessary result of this closing of the valve 20,.the power output of the machine will be decreased and the pressure below atmospheric .1 at point and in the housing 8 will undergo a proportional increase or rise toward atmospheric pressure. 7 Consequently, the aneroid 4 is contracted and in turn moves the control valve 5 up. A pressure is again built up in the chamber .14 and the throttle is opened. Due to this alternate up and down movement of the control valve 5, the piston willbe adjusted to an intermediate point of equilibrium, which is dependent upon the pressure below atmospheric at point 10, so that the piston 15, with increasing engine speed and, therefore, at the same gear ratio with increasing road speed, is gradually moved downwards and the throttle valve is adjusted towardsits closed position to maintain substantially constant power output even as the road speed increases above v1. This substantially constant power is characterized bythe curve portion Bi-Bs. Since the proportional relationship of the characteristics of the pressure below atmospheric at point 10 to the power varies slightly with increasing engine speed, the power is decreased by a certain amount, so that at point A2 it lies somewhat below the adjusted power level N. At point A2, that is, at a road speed via, the power curvell for the second gear, as applied to wideopen throttle, is reached. The automatic, hereinafter described in detail, is so adjusted that in this instant, that is, at a road .speed we, the shift fromfirstto second gear is made. Due to the shift the speed of the engine is reduced, the pressure below atmospheric at point 10 decreases, that is, rises toward atmospheric pressure, and the aneroid 4 is again contracted. A pressure is again built up by the oil in the chamber 14 and moves the throttle plate into wide-open position. At a further increase in road speed the power output rises again from A2 to B2 where the same occurrence as described for point B1 is repeated. At a road speed 1223, the shift to third gear takes place at A3, at point A4 to fourth gear, and at point As to fifth gear, resulting collectively in an only slightly wavy or irregular course of power from Br via A2, B2, A2, B2, A4, B4,, A5, B5, up to point Aw. At point A power output and total resistance of the vehicle in motion are in equilibrium: and the maximum speed vw possible with the power level N is attained.

With a preselected power level, increasing road resistance, for example, when negotiating a hill, moves point Aw towards point B5, and the throttle opens gradually and the power output of the engine increases somewhat to compensate for the increased resistance. This corresponds to a certain ability of accommodation of the engine to adjust itself to changing road conditions. The drivers work is, therefore, substantially reduced, since he is less often compelled to react against the changing road resistance.

As the road resistance continues to increase, the engine at first continues to run with engaged overdrive at wideopen throttle and then at a certain road speed or speed of the driven shaft, the transmission is returned to the fourth speed or gear ratio. This speed v54 preferably lies lower than the speed v at which the corresponding shift from fourth to fifth gear has taken place, in order to retain the hysteresis effect requisite for the stability of the control. At the instant of the shift the power output would then increase from point =E5-on curve V to F on the line connecting B4 and A5. However, the return shift, if necessary, may take place on another curve, for example, a return shift from fourth gear to third gear, at a road speed v43, may take place from E4 to F3.

When the lever 1 is adjusted to position x to provide a higher power level, for example, N, then the occurrences which lead to the automatic shift of the transmission are basically the same as those in the previously described instance. Since, when the lover I is moved to position x, the aneroid 4 and therewith the sliding control valve 5 are raised higher, a higher pressure below atmospheric at point 16 is also requisite in order to enable the control valve 5 to effect a change in the flow of oil from line 13 to line 16 and thus bring about a closing of the throttle. Using power level adjustment N this change in the oil flow is reached at point 31. By the adjustment of the lever 1 to position x, the automatic shiftgear is also affected, so that the road speed must rise to higher values, before the successive shifts to the next higher gear takes place.

If the gear shifts for the power level N are similar to those in the previously described case (N), then the second gear would be engaged only at point A2. Hence, the engine would run at first up to point By with wideopen throttle and from point B1 up to point B2 with gradually closing throttle. This would, however, under certain circumstances have the effect that the engine speed becomes so high that the engine noise drowns the road noise, thereby giving the occupants of the car the impression that too low a gear is engaged. In order to avoid this impression, the road speed at which the first shift takes place can, if desired, be lowered, for example, to value V12. In that event the shift takes place at point C1, at which the wide-open throttle curve II for the second gear is not yet reached. Consequently, the power drops to point Dz immediately after the shift. At the same time the speed of the engine is lowered, the pressure below atmospheric at point 10 reduced and the throttle plate again moved into wide-open position. With increasing road speed the power rises along curve II from point D2 to point B2, at which latter point the adjusted power level N is reached again. The course of power from first to fifth gear or overdrive is therefore given by the curve B1'-Cr -D: -B2'A3'B3'A4'B4' As'-B5 A\v-'. At point Aw, with slightly throttled overdrive, the maximum speed attainable with the power level N is again reached.

In case of adjustment to a still higher power level, for example, N, it is under certain circumstances desirable to locate the shift speed 1 12 for the shift from first to second gear at so low a value that the shift takes place dircctiy from unthrottled first gear, for example, at point B1" on curve I, while the shift from second to third gear takes place at a road speed v23" which is short of the curve III, that is, at point C2". The course of power for the adjusted power level N" is in this case given collectively by the following curve: B1-D2"B2"C2- D3"-B3"-A4"B4"Aw".

The control of the power output can, if desired, be arranged in such a manner that, even with the selected low power level (for example, N) the shift from first to second gear takes place at wide-open throttle position that is, at a point on curve i, or at an intermediate shift point be tween the points B1 and A2, so that an up-shift at throttled engine then occurs for all settings of the power level only in shifting between the higher gear speeds.

When, for example, the selected power output is adjusted to value N and the engine is in an operational stage corresponding to point B3 (hence, in third gear), a sudden increase of the power level (at essentially constant road speed), effected by movement of the lever 1 from position x to position x1 which corresponds to power level N, will produce a return of the transmission to second speed and at a still further increase of the power level, for example, to power level l will produce a further return controller L.

to first gear. The return shift, if desired, can be made mechanically perceptible depending on the adjustment of the spring stop 26 so that the adjustment of lever 1 to a higher power level may be effected only against the resistance of the stop.

if the selected power output is suddenly decreased (for example, out of point B3) the next higher (hence, for example, fourth gear) would be engaged, as soon as the curve IV (at a point located perpendicularly below B3) is undercut. However, a device is preferably provided in the gear shifting device hereinafter described to accomplish such an up shifting only after a certain time lag.

In order to also provide for the use of the engine as a brake in the automatic operation of the transmission, a special brake position x2 may be provided for the lever i and is situated beyond the normal zero or neutral position .m. in this brake position, the side 17 of the piston is steadily supplied with oil under pressure through the steadily open line 16 so that the throttle valve 20 is maintained continuously in closed position. Another mechanical point of resistance (not shown), for example, resilient stop similar to the stop 26, may be provided at position x0 of the lever 1 so that the backward motion to position x2 is perceptible to the driver. Further, the backward motion of the lever to position x2 may be indicated by a signal, for example, a red lamp. The backward motion to position x2 may also be accomplished by means of a special, for example, manually adjustable lever (not shown) which is separate from, or in addition to, the lever 1.

Fig. 4 shows a schematic layout of a preferred automatic gear shifting device embodying the present invention and represented generally by the numeral 7 in Fig. 3. The output control member 191, corresponding to the iever 1 of 3, is connected to an output control device (not shown), which may be identical with the device shown in Fig. 3 and is omitted from Fig. 4 for the sake of clarity. A link M2, connected to the control lever 161, acts upon a controller L consisting of a piston 1d and a pilot valve N5 coupled to the latter by means of a spring it'l which operates to control the pressure of a control fluid in accordance with the position of lever 161.

Oil pressure is built up by a single pump 1M which is continuously in operation or may be replaced by two pumps, one of which may be driven continuously by the engine and the other by the vehicle in motion (for example, from the driven shaft). The pressure oil line 107 extending-from the pump is connected to a pressure regulator R having a spring-loaded piston 215 and communicates with a selector valve W. The selector valve W has a pilot valve member $93 therein operated by a lever 199. The line Hi7 also communicates, through a branch line lid, with the pilot valve 1% of the output The lever 169 is moved to position Z1 for forward gear position and to position Z2 for idling position. Other gear shift positions, for example, for revcrse and motor brake may be provided.

Another line or conduit 111i connects the pump 1% with a speed controller V, consisting of a pilot valve 113 sliding in a cylinder 112 and loaded by a spring 1.14. The spring 114 is influenced by a speed governor 115 which is driven by the vehicle, for example, from the driven shaft of the transmission and thus, increases 3 or decreases the tension of the spring 114 as a function of the road speet. A return line 111a extends from the body or cylinder 112 of the speed controller V to the input side of the pump 106 so that the pressure in the chamber 116 of the speed controller will be determined by the extent to which the end of line 11111 is covered by the pilot valve 113. As the valve 113 moves downwardly, the line 1310 is progressively covered to decrease the return of hydraulic fluid to the inlet of the pump so that the pressure in chamber 116 increases up to the pressure developed at the output side of pump "by

lines

134, 135 and 136.

devices U1, U2, U3 and U4.

9 106. From the control chamber 116 containing the valve 113 of the speed controller V a line 117 leads to a plurality of shifting devices U1, U2, U3 and U4. respectively including pilot valves 118, 119, 120 and 121. The line 117 opens into the

upper portions

122, 123, 124 and 125 of the shifting devices U1, U2, U3 and U4, and through a branch line 126 into the chamber 127 on the side of the pilot valve 113 opposite to the spring 114.

Branch lines

129, 131i, 131, 132 and 133 communicate with a line 128 which is in communication with line 1437 throughthe selector valve 188 when the latter is in forward gear position. The branch lines 129 and 130 open into the upper and lower parts of the cylinder of device U while the

branch lines

131, 132 and 133 respectively open into the lower portions of the cylinders of the devices U2, U3 and U4. The cylinders of the shifting devices are in communication with each other 7 A line 137 leads from the pilot valve cylinder of the shifting device U1 to a shift cylinder for the first gear, a line 138 from the device Uzto the shift cylinder for the second gear, a line 139 from the device Us to the shift cylinder for the third gear, a line 140 from the device U4 to the shift cylinder for the fourth gear and a line 141 from the device U4 to the shift cylinder for the fifth gear.

The control chamber 142 of the controller L which receives the valve 105 communicates through a line 143 with the left side of a piston 144 of the pilot valve 105 and through a line 1435, 1% opening into branch lines :147, 1455, 149, communicates with the lower pressure chambers 151 to 154- of the pilot valves cylinders of the The pilot valves in the devices U1, U2, U and U; are, as clearly shown in the drawing, formed as differential pistons, so that, if oil under pressure is admitted into the central chambers 155 to 153, 21

pressure is built up which acts upon the pilot valves in downward direction.

Aline 159 branchesoif from the line 145 to communicate the output controller L with a piston 16% of a pushrod control assembly D. This assembly includes, be-

sides piston ldil, further .

pistons

161, 162, 163, 164, which have different diameters, and are connected in series under the tension of a spring 165. A pushrrod 166cm the piston 161 is arranged in such a manner that itcomes within the range of the lower lever arm 167 of the power output control member 131 when the piston 161 is in its left-hand end position (as viewed in the drawing). The chamber 16% receiving the piston 161 communicates through .a line 169 with the line 117 and hence withthe control chamber 116 of the speed coni":

troller V. A line 1711 branching off from line 138 extendingto the second gear shifting device establishes communication with the right-hand side of the piston 164, and likewise a line 171 extends from line 139 of the thirdgear shifting device to the piston 163, a line 172 from ;line 140 of the fourth gear shifting device to the piston 162, and a line 173 from line 1 51 of the fifth gearto the piston 161.

The pilot valves 118 to 121 inclusive are urged downwardly by springs 174 to 177 respectively, the springs being so proportioned that spring 174 is the strongest and .177 the weakest. At the points designated by O the lines and control chambers are open to the atmosphere.

The mode of operation of the described device is as follows: Each of the pilot valves 118, 119, 121i and 121 is subjected to a combined load from above exerted by the pressure dependent upon the speed of the driven shaft of the transmission and controlled by the speed controller V, and by the related one of the springs 174 7 wards.

10 which, for example, correspond to the speed below 1 1, all of the pilot valves 118 to 121 are moved up by the selected power output-dependent pressure which is efiective in the chambers 151 to 154 through the

lines

145, 146, 147, 148 and 149. If, in such a case, the selector valve W is in the position shown on the drawing, then the oil under pressure from the pump 106 is passed through the selector valve, through line 129 and the control chamber containing the pilot valve 118, and into line 13-7 to engage the first gear. The lines 138 to 141 for the second to fifith gear shifting cylinders are exposed to atmospheric pressure when the related pilot valves are raised. If the road speed increases with constant power output setting, then the pressure, which is effective upon the pilot valves from above, also increases in such a manner that this pressure at a certain road speed exceeds the pressure from below which is dependent upon the power output and moves the respective pilot valve down- Since the spring 174 is the strongest, the pilot valve 118 of the shifter device U1 is at first, at a definite road speed (1 12), moved downwards. (The automatic shiftgear is shown in this position on the drawing.) When .valve 113 is thus moved downwardly, line 137 is opened to the atmosphere, while the pressure oil enters line 138 119 and thus engages the second gear. Since the forced oil which has entered the control chamber 155 (owing to the fact that the pilot valve is formed as a differentialpiston) exerts an additional downward pressure upon the piston of valve 119, the pilot valve 119, after the shift, is held with increased force in its lower position, so that even if the road speed should decrease again, the shift to low .gear takes place only at a lower road speed than the shift to a higher gear.

The shift to the higher gears takes place in a manner corresponding to the shift from first to second gear, and thatconforming to the speeds v23, 1 34 and v45 of Fig. 3.

When such a low power output is selected that the power dependent pressure even at low speeds of the driven .shaft or low road speeds, is insufficient for the purpose of holding the pilot valves 118,119, 120 and 121 in their upper positions, then, a higher gear is engaged at these lower speeds. If, by way of example, at a definite speed.(for example, vi) the selected power curve vlies below the output level V (Fig. 2), then all the pilot valves are 'in their lower position, This causes the lines 137 to 149 to be opened to the atmosphere, whereas line 141 via the selector valve W,

lines

128 and 133 and chamber 158, is under operating pressure. Accordingly, the fifth gear is engaged. If, at constant road speed, the set power is increased by depressing the pedal 101, which results in an additional tension of the spring 104 andconcurrently an increase in pressure in the chamber 144, then initially the pilot valve 121 is lifted since the spring 177 is weakest. This results in line 141 being opened to the atmosphere, while line 140 is brought into communication with line 136, which in turn communicates, viacontrol chamber 157, with line 132 Thus, the fifth gear is disengaged and the fourth gear engaged. The point of passage from one gear to theother conforms in Fig. 2 to the intersection point of line 1 1 with curve V. With further increase in poweron the perpendicular line frompoint vrto point B1 of Fig. 2 at each respective crossing of the curves IV, 111, H, the respective next following gear is successively engaged.

The mode of action of thepush-rod control device D, forminga part of the assembly of Fig. 4, is asfollows: The selectedpower-dependent pressure is eifective on the right-hand side of the piston through the line 159 while the left hand side of the piston 161'is subjected to the force of spring and also the speed-dependent pressure through the line 169. The pistons 161 to 164 are graded to conform tothe gear shift positions. If the drive, for example, with a selected power level N is in fifth gear (for example, at a driven shaft speed W) and henceforth the speed, at a constant setting of the power, decreases, then the pressure acting in the chamber 168 to the left of piston 161 drops so much, that at a definite road speed (for example adjacent to 1/54) the force acting from the right, being composed of power-dependent pressure upon the piston 160 and the force upon the piston 161 caused by the pressure oil flowing in line 173, predominates, so that the push-rod 166 is moved to the left against the lever arm 167 of the power output control member 101 whereby a force is exerted upon the control member. Simultaneously the speed-dependent pressure in line 117 has decreased so much that the powerdependent pressure in the chamber 154 acting upon the pilot valve 121 surmounts the counteracting pressure in the top chamber 125 and moves the slide valve 121. up, thereby fifth gear is disengaged and fourth gear engaged. As an accompaniment to the disengagement of the fifth gear the pressure in the

lines

141 and 173 drops, while

lines

140, 172 are put under pressure. piston 161, the piston 162 is subjected to the pressure oil acting at the right-hand face thereof. However, since this piston is smaller than piston 161, the force applied by the push-rod of the piston 62 is smaller and at first the speed-dependent pressure in the chamber 168 predominates again, so that the piston with the push-rod 166 is moved again to the right. Not till the speed of the driven side has decreased further (for example, to 1143) does the pressure upon the

pistons

160 and 162 begin to surmount the counterpressure in 'the chamber 168, effecting a repeat movement of the push-rod toward the left and therewith exerting a repeat force upon the lever 101. At this instance shifting from fourth to third gear is actuated by the up movement of pilot valve 120.

In a similar manner, at the passage from third to econd and from second to first gear, a force is exerted by the rod 166 upon the lever 101 by reason of the operating pressure becoming effective upon the piston 163 and then on the piston 164.

Fig. 5 shows an arrangement for using the engine as a braking force. The preselector lever or the power output control member 201 is in the present instance connected through a link 202 with a lever 203 of a power output regulator, for example, that shown in Fig. 3, whereas lever 206 which connects to an automatic gear shift, for example, the gear shift 7 of Fig. 3 which is shown in detail in Fig. 4-, is connected to the link 202 by means of an intermediate transmission. This intermediate transmission is formed by toothed segment 204 connected to link 202, a pinion 205 meshing with the segment, and by a rod 207 which is attached crank-like to the pinion 205.

The power output control member 201 in the illustrated idling position is supported against a movable stop 208 situated on a rod 209 which can be actuated by the selector lever 210. The control lever 201 also has an extension 211 which serves as contact for an electric circuit in which a signal lamp 213 is connected so that as soon as the lever 211 touches the fixed contact 214, the circuit is closed and thus causes the lamp 213 to be illuminated.

In the drawing the control lever 201 is shown in idling position. In order to change to greater power output the lever 201 is moved to the left in the direction of the arrow y, to thereby rotate the pinion clockwise thus moving the crank rod 207 to the left. When applied to the automatic gear shifting assembly of Fig. 4, this movement of rod 207 causes the power-dependent pressure in chamber 142 to be correspondingly increased.

If it is desired to use the engine as a braking force, then the control lever 201 must be moved in the direction of the arrow y. However, this is only possible if the control lever 210 is moved into position 210 to retract the stop 208. The pinion 205 is rotated by counter- Now instead of clockwise movement of lever 201 in the direction y and this likewise adjusts the automatic shiftgear on the linkage 206 for greater power through the lever 206. However, at the same time the output regulator of the engine on the lever 203 is adjusted for lesser power and therein lies the adaptability of the engine as a braking force.

Simultaneously with moving the lever 201 in direction y the

contacts

211, 214 are closed to cause the signal lamp to be illuminated.

The invention is not only applicable to carburetor engines but also in spirit and scope to other engines, for example diesel engines. In this latter case instead of utilizing a throttle valve for control the amount of fuel to be injected, for example, delivered by a fuel injection pump, is controlled. In this case also a pressure below atmospheric could be used as the power-dependent value or factor with this low pressure being induced by a contraction or restricted neck corresponding to the carburetor air venturi 10. It is to be understood that the invention is not limited or restricted to the employment of such a pressure below atmospheric as the powerdependent control value or factor, and that other changes and modifications may be made in the described embodiments without departing from the scope or spirit of the invention as defined in the appended claims.

What is claimed is:

1. Apparatus for controlling an internal combustion engine drive assembly including a transmission having several gear ratios interposed between the engine and a driven shaft; said apparatus comprising feeler means responsive to an operating characteristic of the engine which varies substantially proportionally to the power output of the engine, power output control means actuated by said feeler means for manipulating the engine throttle so that the power output tends to be maintained at a preselected value, adjusting means operatively connected to said feeler means for adjusting the latter to vary the preselected value of power output which said control means tends to maintain, a shift device for shifting the transmission, means actuating said shift device in response to changes of speed of the driven shaft of predetermined values, and means operatively connected to said adjusting means and to said shift device actuating means for adjusting said predetermined values of driven shaft speed in response to variations of said preselected value of power output.

2. Apparatus according to claim 1; wherein said feeler means includes an aneroid, and means for subjecting said aneroid to the reduced pressure at the throat of the carburetor venturi associated with the engine; and wherein said power output control means is operatively connected to said aneroid and is effective to move the engine throttle in a closing direction when said reduced pressure at the throat of the carburetor venturi falls to a value indicating that the engine power output has exceeded said preselected value thereof.

3. Apparatus according to claim 1; wherein said means operatively connected to said adjusting means and to said shift device actuating means is effective to increase said predetermined values of driven shaft speed simultaneously with the increasing of the preselected power output by said adjusting means.

4. Apparatus according to claim 1; wherein said shift device comprises a pilot valve for each gear ratio of the transmission, and means controlled by each of said pilot valves for effecting the shift of the transmission to the respective gear ratio; and wherein said means actuating the shift device includes means urging each of said pilot valves in one direction with a force proportional to the speed of the driven shaft.

5. Apparatus according to claim 4; wherein said means operatively connected to said adjusting means and to said shift device actuating means includes means urging each of said pilot valves in the opposite direction with a 13 force proportional to the value of the selected poweroutput.

6. Apparatus according to claim 1; further comprising means actuated by-said shift device and operative to displace said adjusting means in response to the operation of said shift device in-shifting the transmission from a higher gear ratio to a lowergear'ratio.

7. A control device-for'a'drive assembly including an internal combustion engine, a driven shaft and a multigear ratio transmission therebetween; said device comprising means for throttling the power of the engine, feeler means responsive to an operating characteristic of the engine which varies substantially proportionally to the power output of the engine, said throttling means speeds of the driven shaft, and means operatively connected to said shifting device for increasing the values of said predetermined speeds in response to the increase of the selected power output by said adjusting means.

8. A control device according to claim 7; including resilient means adjustably positioned in the path of movement of said adjusting means so that the latter can be manipulated to set a power output value higher than that defined by the position of said resilient means only by overcoming the yieldable resistance of the latter.

9. A control device for a drive assembly including an internal combustion engine, a driven shaft and a multigear ratio transmission therebetween; said device comprising an air intake for the engine having a restricted throat, a throttling element in said air intake, a conduit communicating with said restricted throat, a sealed housing connected to said conduit so that the pressure in said housing varies in response to pressure changes at said restricted throat, an aneroid in said housing, control means operatively connected to said aneroid, adjusting means connected to said aneroid for varying the initial position of the latter and of said control means, actuating means for manipulating said throttling element in response to the position of said control means so that a decrease of pressure at said throat below a predetermined value, as determined by the initial position of said aneroid, will result in closing movement of said throttling element, a shift device for shifting the transmission in response to the attainment of predetermined speeds by the driven shaft, and means actuated by said adjusting means and operatively connected to said shift device to increase said predetermined speeds of the driven shaft at which the transmission is shifted in response to movement of said adjusting means in the direction operative to increase the pressure below atmospheric at said throat at which said throttling element begins said closing movement.

10. A control device for a drive assembly including an internal combustion engine, a driven shaft and a multigear ratio transmission therebetween; said device comprising means for throttling the power of the engine, means controlling the operation of said throttling means in response to an operating characteristic of the engine which varies substantially proportionally to the power output of the engine, adjusting means operatively connected to said controlling means for varying the power at which the latter becomes effective to operate said throttling means, a shift device operative in response to predetermined speeds of the driven shaft to shift the transmission, and means actuated by said adjusting means and operatively connected to said shift device to normally vary said predetermined speeds in accordance with variations in the power at which said throttling means becomes effective, said adjusting means in one position fit being operative to condition said controlling means for maintaining said throttling means continuously in a power throttling position.

11.,A control device according to claim 10; wherein said means actuated by said adjusting means and operatively connected to said' shift device includes link means constructed and arranged to inversely vary said predetermined speeds with respect to the power at which said throttling means becomes effective when said adjusting means is moved to said one position thereof.

12. An hydraulic control device for a drive assembly including an internal combustion engine, a driven shaft and a multi-speed transmission therebetween; said device comprising means for selecting a definite engine power,

-' adevice =for'establishing an hydraulic pressure proportional to the selected engine power, a device for establishing an hydraulic pressure proportional to the speed of the driven shaft, pilot valves, gear shift operators, said pilot valves controlling the flow of fluid pressure to said gear shift operators, means for applying a load to each of said pilot valves in one direction by said pressure proportional to the speed of the driven shaft and in the other direction by said pressure proportional to the selected power in such a manner that at constant selected power and increasing speed of the driven shaft said pilot valves for the separate gear shift operators are successively moved in said one direction into a position effecting the shift of the related speed.

13. A control device according to claim 12 wherein said pilot valves are formed as differential pistons, means directing the hydraulic pressure which actuates the shifting against the differential area of each piston as soon as the respective pilot valve has been moved into gear shifting position, thedifferential area of each piston being so arranged that the pressure brought to bear on said area acts in the same direction as said pressure proportional to the speed of the driven shaft.

14. A control device according to claim 12 including, resilient elements which are effective upon said pilot valves in the same direction as said pressure proportional to the speed of the driven shaft, the resilient element which is associated with a lower gear shift position being in each case stronger than the resilient element which is associated with a higher gear shift position.

15. A control device according to claim 12 including, a control piston for each of the different gear shift positions, the related one of said pistons being placed under hydraulic pressure when the respective gear is engaged, another piston, means for applying a pressure against the latter proportional to the selected power, resilient means applying a yieldable force counteracting said pressures, means applying the pressure proportional to the speed of the driven shaft in a direction to also counteract said aforementioned pressures, and means for transmitting the movements of said pistons caused by the differences of said pressures and said yieldable force to said means for selecting the power of the engine in such a manner that said piston movements are perceptible in said selecting means.

16. A control device for a drive assembly including an internal combustion engine, a driven shaft and a multigear ratio transmission therebetween; said control device comprising means for setting a selected power to be imparted to the driven shaft and for automatically controlling the engine to maintain the power output substantially constant at said selected power so that the performance of the engine remains substantially uniform at all speeds of the driven shaft, a shift device for shifting the gear ratio of the transmission in response to predetermined speeds of the driven shaft, and means operatively associated with said shift device for varying said predetermined speeds in response to changes in said selected power set by the first mentioned means.

17. Control device according to claim 16 wherein said first mentioned means comprises an adjusting device for defining said selected power, a throttling member for controlling the power output of the engine, means responsive to the actual power output of the engine, and means for manipulating said throttling member by said adjusting device and the last mentioned means in such a manner that said throttling member is maintained in open position so long as the selected power is not attained, and is moved towards closed position as soon as said selected power is attained.

Hayes May 31, 1932 Bloxsom May 30, 1933 1 6 Erban Aug. 8, Fleischel Mar. 5, Drabin Apr. 16, Vincent July 16, Livermore June 7, Brunner Oct. 31, Hale Dec. 16, Scott-Paine Sept. 28, Hefel Sept. 28, Lang et a1 June 27, Aspinwall Nov. 11, Britton Aug. 24, Peterson et al Nov. 23,