US2439325A - Governing arrangement with servomotor - Google Patents

Description

April 6, 1948.

Filed May 19, 1944 2 Sheets-Sheet J.

I N V E N TOR Bvtz Mas-07480;

Mm Bu g whmkkw April 6, 1948. F. WIESENDANGER GOVERNING ARRANGEMENT WITH SERVOMOTOR Filed May 19, 1944 2 Sheets-Sheet 2 J 26 J J llllll ATTORNEYS Patented Apr. 6, 1948 v GOVERNING ARRANGEMENT WITH SERVOMOTOR Fritz Wiesendanger, Winterthur, Switzerland, as-

signor to Sulzer Freres, Soclt Anonyme,

Winterthur, Switzerland Application May 19, 1944, Serial No. 536,252

- l The invention relates to a governing arrangement having a servomotor and an adjusting piston which returns the control member of the servomotor and whose motion is effected independently of the servomotor piston through actuation by pressure medium controlled by the control member of the servomotor piston; and in particular to an output governing means in vehicles driven by internal combustion engines with electrical power transmission.

, Known output governors which act with the aid of a servomotor and in which the function required of the governing arrangement renders impossible a mechanical returning of the control member by the servomotor piston, suffer in certain circumstances from oscillations caused by over-regulation.

In order to prevent these oscillations, it has already been proposed to return the control member of the servomotor by means of a piston which is actuated at the same time as the servomotor piston by the control member of the latter and is not mechanically connected to the servomotor piston. This known form of return arrangement has the disadvantage that it acts immediately and thus only reduces the opening of the control member. In practice it amounts to the same thing as using a control member with a smaller cross-section for the servomotor.

In order to prevent the oscillations presenting themselves, it is proposed in the present invention that the returning action of the adjusting piston should be delayed relatively to the motion of the control member by means of throttling members in the pipes which connect the adjusting piston to the control member.

This arrangement has the advantage that when the governor of the internal combustion engine is deflected to a certain extent from the position corresponding to the closing position of the control member of the servomotor, this control member now opens rapidly and immediately. Only when the deflection of the engine governor no longer increases so rapidly does the returning piston gradually come into action and reduce the opening of the control member. The return motion is thus delayed.

The essential effect of the throttling described in the present invention only makes itself felt when the engine governor has reached a maximum deflection and is again returning to the position of equilibrium. This reversal in the movement of the engine governor means that the output governor is sufflciently loaded or relieved and should now return to the closed position.

7 Claims. (Cl. 290-17) In the absence of a throttled return system this does not happen, but instead the control member of the servomotor only comes into the closed position when the engine governor has 'again reached the normal position. If, however,

the supply of pressure medium to the returning piston is throttled, the piston cannot go back very quickly" into its middle position. Thus the control member of the servomotor comes into the closed position long before the engine governor is in the normal position.

If the degree of throttling is rightly set, the control member of the servomotor oscillates steadily about the closed position as long as the engine governor is returning towards the normal position. The phase displacement of of a period between the engine governor and the output governor, which is present when the throttling arrangement is not used, is thus eliminated. During the time in which the two governors previously moved in opposition to each other, the output governor now only remains at a standstill.

In the drawings,

Fig. 1 illustrates diagrammatically a dieselelectric drive installation embodying my invention;

Fig. 2 is an enlarged view of an alternative return spring arrangement for my invention; and

Fig. 3 is the servomotor control system of my invention alone.

In Figs. 1 and 3 the internal combustion engine i is provided with a governor 3 driven from the crankshaft by means of the gear 2. The collar 4 of the governor 3 adjusts through the linkage 5 to E4 the control member E5 of the servomotor I6, whose piston I1 is connected to the contact lever I 8 of a regulating resistance I9 which, for instance, serves for the regulation of the excitation of the generator 40 provided with an armature winding 4| and a field Winding 42 and driven by the internal combustion engine i. The armature winding 4| is connected through an operating switch 43 to motors 44. The field winding 42 of the generator 40 is electrically connected to the armature 45 of an exciter generator 46 which isalso driven by the engine I. The exciter 46 has a field winding 41. The circuit 48 with the armature 45 of the exciter 46 and the field winding 42 of the generator 40 contains the regulating resistance I9. The generator 40 produces the current for the driving motors 44 of a rail vehicle not shown in the drawing.

The device 20 with the adjusting piston 21 serves to return the control member l5 of the servomotor IS. The adjusting piston 2| is rejusting to exactly the load given by the device 21,

28 for setting the value required. If the load alters on account of any external influences, for instance the running of the vehicle on to an incline, or on account of any internal influences arising from the engine, and if then the load 33 to the upper surface of the piston II. In this way the resistance I9 is increased, that is to say the excitation of the generator is decreased.

At the same time, however, pressure medium also passes through the branch 32 to the upper surface of the piston 2i, which moves downwards and, by displacing the fulcrum I4, turns the lever I3 about the point I2 and thus returns the slide valve I5 a little towards its closed position. The pressure medium below the pistons I1 and 2I escapes through the pipes 35 and 38 and the passage 34. The movement of the piston 2i is nevertheless more or less strongly retarded by the throttling members -3'l and 38, so that the valve I5 in any case retains an upward deflection, as long as the collar 4 continues to move downwards. The relief of the engine is then great enough when the collar 4 comes to a standstill in its downward movement.

If, when the collar 4 again moves upwards, the piston 2i were in the middle position, the valve I5 would actuate the piston I! so as to relieve the engine, until the governor 3 is again in the normal position shown. This whole period of upward motion of the collar 4 would thus represent an overreguiation. In reality, at the moment when the collar 4 again moves upwards from its lowest position, the piston 2i is not in its middle position, but below this. The valve I5 thus comes into its closed position, considerably earlier than if the adjusting piston 2i were not present and the fulcrum I 4 were fixed.

At the moment when the valve I5 is in its closed position, the'piston 2| again moves slowly into its middle position as a result of the pressure in the spring 23 and the imperfect'sealing. If this takes place too slowly, the valve I5 moves downwards out of the closed position, which leads to' an acceleration of the upward movement of the piston 2|,

By the setting of the throttling members 31 and 38 it is possible to adapt the speed of the piston 2I to the requirements of the governing process. If it should happen that the valve I5 moves temporarily downwards out of the closed position, no harm is done since a relatively rapid upward movement of the collar 4 from its lowest position into the normal position indicates that the relieving effect has already been too great. It is clear from this that the harmful overregulation of the governing arrangement is greatly reduced through the piston 2I or in'some circumstances completely precluded.

If the disturbance of equilibrium is caused by insufllcient loading, the governing process takes place in the opposite direction in a manner which is in principle the same, so that a description of this process is not necessary. 4

If the lever 28 is turned to the right to reduce the normal setting of the load, the fulcrum II is moved upwards with the straight guiding means 21, while the lever Ill turns about the joint 9 of the lever l, which is held firm by the collar 4 through the lever 5 and the link 6. This displacement of the fulcrum II immediately takes the same effect as an increase of the load. The same process then takes place with regard to the members of the servomotor and the return arrangement as is described above.

As a result of the relieving efiect the collar 4 moves upward a little, and the valve I5 only returns finally to its closed position when the pointat 8 of the governor 3 has come to rest at a somewhat lower value on the scale 0 to 10. The scale 0 to 10'for the pointer -8 indicates the amount of fuel injected into the engine from the smallest amount at 0 to the maximum at 10. Pointer 8 is connected to fuel regulating bellcrank 1, la which operates rod 8a controlling the fuel supply device I! of engine I (Fig. 1). If the engine I is designed for adjustable speeds, it may be of advantage to combine the output setting device with the device for setting the speed, so that each speed corresponds to a definite output.

The normal position of collar 4 of engine speed governor 3 is definitely adjustable for any given engine speed setting, since for any set position of fulcrum II, control valve I5 holds the neutral position for only one certain position of collar 4. Simultaneously, fuel-regulating bell crank l is definitely positioned by any position assumed by collar 4, and the amount of fuel to be injected with respect to any such position is thus predetermined. If the fulcrum II is displaced by means of lever 28, it can be seen from the foregoing that the neutral position of valve I5 is reached with a new position of collar 4, i. e. at another speed of engine I, and that a new fuel setting is made, since another position of crank l (and of pointer 8) will correspond to the new position of collar 4. Therefore, by means of lever 28 the speed and fuel supply of engine I may be varied,

The conditions of regulation of the governor 3 are in certain circumstances not the same when the normal load setting is exceeded or not attained. When the normal setting is not attained, for instance, the quantity of fuel injected is regulated down to the fuel setting 0. As a result the speed changes only slightly. When the normal setting is exceeded, on the'other hand, the maximum fuel setting is perhaps very rapidly reached and the speed falls correspondingly. It may then be expedient to set the speed of the piston 2I differently for the two directions of motion.

This can be done most simply by the use of a differential piston, as shown in Figs. 1 and 3, in which, because of piston rod 22, the eflective area of piston 2| exposed to pressure from above is less than that exposed below. A similar end can be attained, as shown in Fig. 2, by using two springs 23 and 23a with different characteristics instead of the one spring 23 for returning the adjusting piston 2| into itsmiddle position, one of the two springs coming into action for each of the two directions of motion of the piston 2i. Thus, weak spring 23 opposes downward motion 0! piston 2! while stiff spring 23a opposes upward.

I claim:

1. Regulating apparatus for the simultaneous static regulation of prime mover and astatlc regulation of electric generator excitation in vehicles driven by internal combustion engines with electrical power transmission including in combination an internal combustion engine, means for regulating the fuel supply to said engine, an electric generator driven by said engine, means for regulating the excitation of said generator, a speed governor driven by said engine, means influenced by said governor for adjusting said fuel supply regulating means whereby for any given engine speed there is a predetermined fuel setting, a hydraulic servomotor for adjusting said generator excitation regulating means, and control means for said servomotor influenced by said governor comprising a control member and an adjusting piston for returning the control member, pipe means for supplying fluid to and removing fluid from the adjusting piston'under the action oi the control member, separate pipe means for supplying fluid to and removing fluid from the piston oi the servomotor under the action of the control member, throttling means in each of said pipe leans, means connecting the speed governor to the control anember, whereby the governor adjusts the positions of the control member and the throttling means retards the return action oi the adjusting piston relative to the motion of the control member.

2. Regulating apparatus for the simultaneous static regulation of prime mover and astatic regulation of electric generator excitation in vehicles driven by internal combustion engines with electrical power transmission including in combination an internal combustion engine, means for regulating the fuel supply to said engine, an electric generator driven by said engine, means for regulating the excitation of said generator, a speed governor driven by said engine, means infiuenced by said governor for adjusting said fuel supply regulating means whereby for any given engine speed there is a predetermined fuel setting, a piston-type hydraulic servomotor for adjusting said generator excitation regulating means, control means for said servomotor influenced by said governor, and manual means for regulating the 'infiuence'of said governor on said control means whereby the normal load level to be maintained on said engine by the regulated excitation level of the generator can be set, said control means comprising a control member, an adjusting piston for returning said control member, a separate pipe means connecting said control member to one side of said adjusting piston and one side of the servomotor piston, a throttle in the pipe entering the one side of said adjusting piston, a separate pipe means connecting said control member to the other side of said adjusting piston and to the other side of said servomotor piston, a throttle in the pipe entering the other side of said adjusting piston, said pipes being for the passage of liquid from said control member to operate said pistons, a linkage with a pivot point set by said manual regulating means connecting said speed governor, said control member and said adjusting piston, said adjusting piston being so connected to the linkage that its movement eifects a return of said control member at any position of said speed governor, and means for setting said throttles to retard the the motion of the control member.

3. Apparatus according to claim 2 which com prises an adjusting piston constructed as a differential piston whereby the retardation is rendered different in one direction of motion than in the other direction of motion.

4. Apparatus according to claim 2 which comprises differential spring means ior returning the adjusting piston to its middle position. v

5. Apparatus according to claim 2 which comprises means for regulating the throttles to vary the action of the adjusting piston.

6. Regulating apparatus for the simultaneous static regulation of prime mover and astatic regulation of electric generator excitation in vehicles driven by internal combustion engines with electric power transmission including in combination an internal combustion engine, means for regulating the fuel supply to said engine, an electric generator driven by said engine, means for regulating the excitation of said generator, a speed governor driven by said engine, means influenced by said governor for adjusting said fuel supply regulating means whereby for any given enginespeed there is a predetermined fuel setting, a hydraulic servomotor for adjusting said generator excitation regulating means, and control means for said servomotor influenced by said governor comprising a source of fluid under pressure, a movable control valve controlling the flow of fluid from said source, conduit means leading from said control valve to said servomotor, said conduit means being cut of! from said source by said control valve in the neutral position, supplying fluid from said source to operate said servomotor in the sense of greater excitation as said control valve is displaced to one side of the neutral position, and supplying fluid from said source to operate said servomotor in the sense of lesser excitation as said control valve is displaced to the other side of the neutral position, an adjusting piston for returning said control valve to the neutral position, further conduit means leading from said control valve to said adjusting piston, said further conduit means being cut off from said source by said control valve in the neutral position, supplying fluid from said source to displace said adjusting piston in one direction from a'central position as said control valve is displaced to one side of the neutral position, and supplying fluid from said source to displace said adjusting piston in the other direction from said central position as said control valve is displaced to the other side of the neutral position, means responsive to said speed governor for moving said control valve to one side of the neutral position in response to a rise in speed thus producing a greater excitation and to the other side of the neutral position in response to a fall in speed thus producing a lesser excitation, said governor responsive means being also influenced by said adjusting piston to return said control valve to the neutral position, and throttling means in the further conduit means connecting said control valve to said adjustin piston whereby the return action of the adjusting piston is retarded in time relative to the motion of said control valve.

7. In output governing apparatus for vehicles driven by internal combustion engines with electrical power transmission including an electrical generator, the improvement which comprises a speed governor driven by the engine, a regulating device for varying astatical-ly the output oi the servomotor including a control member and a regulating piston therefor, means for regulating statically the fuel supplied-to the engine, linkage connecting the governor on one hand to the control member and its regulating piston and on the other hand to the fuel regulating means, an adjustable fulcrum for the linkage, means for setting the fulcrum in different positions to impose variations on the action or the governor, a pipe system for servomotor motive fluid connecting the control member and its regulating piston. and throttling means in the pipe system whereby the action of the regulating piston providing a return motion for the control member is retarded relative to the initial motion 01' that member.

FRITZ WIESENDANGER.

REFERENCES CITED Thefollowing references are of record in the file 01' this patent:

UNITED STATES PATENTS Number Lemp Feb. 13, 1917 Number Number 749,059 224,049 25 Name Date Wettstein June 25. 1929 Birmann Feb. 25, 1930 Schaer Oct. 6, 1934 Carlson June 30, 1936 Schaer Aug. 4, 1936 Simmen Nov. 17, 1936 Sousedik Sept. 2-7, 1938 Carlson Dec. 13, 1938 Schlaepi'er Jan. 31, 1939 Manteufiel Aug. 15, 1939 Brunner Oct. 10, 1939 Brunner Nov. 14, 1939 Dllworth July 9, 1940 Dilworth Dec. 16, 1941 Oswald Dec. 1, 1942- Smith Feb. 9, 1943 Schwendner et al. Dec. 12, 1944 FOREIGN PATENTS Country Date v France May 2, 1933 Germany July 7, 1910

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