US2547781A

US2547781A - Apparatus for regulating the indicated power of hot gas motors

Info

Publication number: US2547781A
Application number: US614572A
Authority: US
Inventors: Rinia Herre; Brey Heinrich De
Original assignee: Hartford National Bank and Trust Co
Current assignee: Hartford National Bank and Trust Co
Priority date: 1943-05-29
Filing date: 1945-09-05
Publication date: 1951-04-03
Anticipated expiration: 1968-04-03

Description

April 3, 1951 H. RINIA ETAL 2,547,781

. APPARATUS FOR REGULATING THE INDICATED POWER OF HOT GAS MOTORS Filed Sept. 5, 1945 Herre Ri-nia & Heinvickcle Brey INVENTORS BY% AGENT Patented Apr. 3, 1951 APPARATUS FOR REGULATING THE INDI- CATED POWER OF HOT GAS MOTORS Herre Rinia and Heinrich de Brey, Eindhoven, Netherlands, assignors to Hartford National Bank & Trust 00., Hartford, Conn., as trustee Application September 5, 1945, Serial No. 614,572 In the Netherlands May 29, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires May 29, 1963 6 Claims.

1 The present invention relates to a method of regulating the indicated power of a hot-gas motor and to a hot-gas motor to which such a reging in the cylinder, in other words a change of the pressure level of the cycle. In this case it is assumed that the compression ratio, i. e., the ratio between the maximum and'the minimum pressures in the cylinder, remains constant. Constructionally this regulation may be realized by admitting gas into the cylinder or by removing gas therefrom at one or more points of the cycle.

Regulations of the second kind are carried out while maintaining the average pressure level constant, but by varying the compression ratio. Such a regulation may be constructionally realized by a changing the phase between the motions of the piston and of the expeller. Another possibility consists in having the interior of the cylinder brought into communication with a separate chamber of variable volume or with one or more chambers of different total volume. Although those forms of construction can be realized in practice with satisfactory results, this realization however, entails some drawbacks. The change of the phase angle between the motions of "the piston and of the expeller requires an adjusting device between the two driving means. Regulation by adding separate chambers only affords a step-by-step change of the power. Continuous change is possible if the volume of this added chamber is continuously variable, but, since the pressure prevailing in this chamber is usually different from the atmospheric pressure, the adjusting force has a high value.

A primary object of this invention is to provide means in a hot-gas engine for changing the power output of said engine upon load demand changes of the same without the previous defects in such control.

Another important object of this invention is to control the power of a hot-gas engine by various fluid flow resistances selectively made in accordance with load demands of said engine.

Other objects, features and advantages of the present invention will become apparent as the description of the invention proceeds hereinafter.

Fig. 1 shows an indicator diagram of a hotgas motor obtained by the present invention.

Fig. 2 represents, partly diagrammatically, a hot-gas motor with a regulating system according to the invention and;

Fig. 3 represents another embodiment of a power regulating device used with the engine shown in Fig. 2.

The regulation of power according to the invention belongs to that of the second kind mentioned above. With respect to the previously proposed or known regulations it affords the advantage of simplicity accompanied by a continuous course.- of power change and an adjusting force of low value.

According to the present invention, the interior of the motor cylinder is brought into communication with another chamber through the intermediary of a flow resistance to be regulated either automatically or manually. A regular exchange of gas between the cylinder and the other chamber takes place through this flow resistance, i. e. a flow out of the cylinder if the pressure prevailing in the latter exceeds the pressure in the other chamber and a flow towards the cylinder if the pressure in the latter is lower.

The ratio between the maximum pressure and the minimum pressure in the cylinder is thus reduced, so thatthe area of the diagram decreases. The value of this ratio can be exactly regulated by means of the value of the flow resistance'. In this manner it is therefore possible as by means of a regulator to vary the motor power of the motor to a desired value for handling a given external load.

According to one embodiment of the present invention a communication between the motor cylinder and the other chamber is provided parallel to the flow resistance to be regulated, in the form of two channels which can be shut off and which allow the passage of gas only in opposite directions. If the closure of one of these channels is removed the gas can flow from the motor cylinder into the other chamber, as long as the pressure prevailing in the former exceeds the pressure in the other chamber, the gas being prevented from flowing back by a valve provided in this channel. If the closure of the other channel is removed, the gas can only flow be raised to a maximum, so that the indicated motor power can rapidly vary between maximum and minimum. The maintained regulation of the gas current between the motor cylinderand the other chamber via the flow resistance to be regulated serves for a slow control of the desired power.

The closure means of thesaid channels which allow th passage of gas only in mutually opposite directions may likewise be subject v to the action of the regulator, which closure means, if desired, may be mechanically combined with the flow resistance to be regulated.

The invention will be explained more fully with reference to the accompanying drawing which represents, by way of example, one embodiment thereof.

In Figure 1, l denotes the indicator diagram of a hot-gas motor. Asindicated by the legends,

the abscissa represents the motion of the piston whereas the ordinate represents the variation of the pressure prevailing in the cylinder in the different positions of the piston. The diagram II], which is representedby a full line, represents the indicator diagram in case of the full power of the motor. The pressure in the cylinder varies in this case between the maximum pressure H and the minimum pressure 12. The average level of the pressure is located at i3, the indicated motor power is determined by the area enclosed by this diagram.

When the power regulation according to the invention is started, i. e., when the interior of the working cylinder is brought into communication with an auxiliary chamber via regulated flow resistances, the pressure in the working cylinder, if it originally exceeds the pressure prevailing in this auxiliary chamber, will then decrease through any one of these flow resistances whereas on the other hand the pressure in the cylinder will be raised if its pressure is lower than that which prevails in the said chamber. The diagram consequently acquires the configuration represented in the figure by a dotted line I 6, in which event the maximum pressure decreases to a value M and the minimum pressure increases to a value l5. Assuming that in the said auxiliary chamber there prevails a pressure which is equal to the average pressure level E3, the average pressure level in the working cylinder also remains constant after this regulation has started. The pressure in this auxiliary chamber automatically adjusts itself approximately to the said average pressure level l3 when the communication between the working cylinder and this auxiliary chamber has already existed for some time.

The auxiliary chamber may act as a separate closed vessel but any convenient space present in the motor may also be utilized for this purpose. Hot-gas motors frequently have a crank case which, for the purpose of reducing the leakage losses from the cylinder along the piston is hermetically sealed with respect to the surroundings. This sealed crank shaft box may act without any objections as the auxiliary chamber for the above-mentioned regulations. Care must be taken to ensure that the chamber utilized as the auxiliary chamber does not become too small with respect to. the volume of stroke, for in a small auxiliary chamber there will soon be produced a counterpressure of such value that the range of regulation becomes only small. This is especially so inthe case of a low number of revolutions, in which event consequentl; a fairly 4 large period of time is available for the medium to flow to and fro through the flow resistance. An auxiliary chamber which is small with respect to the volume of piston stroke acts as an additional clearance even in case of a smaller flow resistance. The sealed auxiliary chamber for the regulation ofiers the advantage that the same gas always remains -.in circulation in the motor so that this method of regulation may also be applied to motors having a particular type of gas, for example of hydrogen or helium.

Figure 2 represents, for the major part diagrammatically, the construction of a hot-gas motor in connection with the present power regulation. Within a cylinder 26 are movable an expeller 2| and a piston 22 which are actuated from-a .common crank shaft 23. The force exerted on the piston is transmitted to this crankshaft by means of the usual crank 2 3 from which the expeller 2| is driven by means of an eccentric 25. A crank shaft 23 is present in a crank case 25 which is hermetically sealed with respect to the surroundings.

For regulating the power of the motor the cylinder 26 communicates with the crank shaft box 26 through a channel 29-2l'. By means of a cylindrical bush or plunger 36 which is movable in this channel along an elongated and narrow slit-shaped aperture 28 the channel 29.' 21 can be closed either completely or partly. The bush 30 can be raised and lowered in the channel 21 in such manner that in the extreme position the slit-shaped aperture 28 between the channel 29 and the channel 2 can be completely closed. When the bush or selective fluid-resistance control means 36 is raised, part of this slit 28 is opened so that the communication between the cylinder 26 and the crank shaft box 26 is established. The gases flowing through this junction channelZ-l must, now, however, pass through the narrow slit 28 in which they encounter an appreciable flow resistance whose value is higher when a greater length of this slit is covered by the cylindrical bush 3B. The position of this selective fluid resistance control means with respect to the slit is acted upon by the speed regulator of the motor, which regulator of the type shown in the Patent No. 336,093 to Daelen can adjust the position of the bush through the intermediary of a lever 32 and a thin rod 31.

The conventional structure of the said regulator, the details of which form no part of the present invention, will now be described. A rod 46 is mounted for rotation on a gear box diagrammatically represented in Figure 2 with the use of a suitable legend. The said gear box houses suitable gearing (not shown) for dri-vingly connecting the crankshaft 23 with the rotatable rod 46. Obviously, the speed of rotation of the rod 46 will vary with the speed of rotation of the crankshaft. Mounted on the rod for rotation therewith is a collar 5! affixed to the said rod 16 by means of conventional key means '52. Centrifugal weights 49 are connected by hinge rods 58 to said fixed collar 5| and to a slidable collar 45. The aforesaid lever 32 is affixed to said collar 45 for vertical movement therewith. A spring 41 pressed at one end thereof against a third collar 48 fixed on rod 46, has the other free end abutting slidable collar 45 to bias the latter upwardly.

It will be apparent from the foregoing that the greater the speed of rotation of the crankshaft 23, .and with it that of rod 46; the greater the radial displacement of the centrifugal weights 49 and the lower the position of collar 45 against the action of spring 41. Since valve 3|] moves vertically with collar 45, the smaller will be the portion of aperture 28 uncovered. It follows, of course, that momehtary reduction in the speed of crankshaft 23 (as by increased load thereon) results in more of aperture 23 bein uncovered.

The cross-section of the rod 3| is taken so small that the force exerted on this rod due to the overpressure prevailing in the channel 21 is substantially neutralized by the weight of this bush and of the parts associated therewith. The regulation may therefore occur without a great regulating force being required.

The power regulating mechanism represented in Figure 3 consists of a casing 35 in which several channels are provided. In the casing is provided a central bore in which a specially constructed plunger 39 can be raised and lowered. Through the intermediary of a lever 32 this plunger is connected to a regulator (not shown) but of the type mentioned above sothat the position of this plunger may be made dependent upon the desired power of the motor. In the casing 35 are provided three

parallel bores

36, 31 and 38 which join at right angles the central bore containing the plunger 39, so that the plunger 39 can release one bore at the most. These bores 36, 31 and 38 open into a common channel 21 which communicates with a separate auxiliary chamber 26. On the other side of casing 35, the three bores 33, 31 and 38 are likewise connected by means of a common channel 29 which is in open communication with the motor cylinder as shown in Fig. 2.

The undermost bore 38 of these three bores retains a non-return valve 49 which only opens for a gas current which moves from the chamber 23 through the channel 21, the bore 38 and the channel 29 to the motor cylinder. The bore 31 contains a valve M of similar construction which opens in just the opposite direction. The bore 33 is locally narrowed and thus forms a resistance to any liquid medium flow between the motor cylinder and the other chamber 26. This flow resistance is regulable since the plunger 39 exhibits a similar narrow aperture 44 which may be caused to communicate more or less with the bore 36 by raising and lowering the plunger 39.

Furthermore, the plunger 39 is constructed in such manner that during the ordinary operation of the motor the

bores

31 and 38 are completely closed. If the external load on the motor is suddenly greatly increased, the direct result thereof is a decrease of the speed. The power regulator starts functioning and lowers the plunger 39 to such an extent that a circulation aperture 42 in this plunger opens the bore 38. As long as the gas pressure in the motor cylinder is lower than the gas pressure available in the vessel 26, a current of gas will flow towards the motor cylinder. A return of the gas is impossible since this is prevented by the non-return valve 49 and the two

other bores

36 and 31 are closed by the plunger. For a short time a maximum quantity of gas consequently flows towards the cylinder so that the indicated power greatly increases. Conversely, suppression of the external load results when the regulator by displacing the plunger 39 brings the aperture 43 in line with the bore 31, thus establishing only fluid flow from the motor cylinder towards the vessel 26.

During the ordinary operation of the-motor. when rapid regulation is impossible,- the

bores

31 and 38 are closed. For adjusting the power to a value lower than that which can be obtained in the above-mentioned manner the open ing 44 is caused to register with the bore 33.

What we claim is:

1.'In a hot-gas engine with a working chamber, a control system comprising a distinct chamber, means including a variable flowresistant circulation aperture open at all times for coupling said distinct chamber to said working chamber, valve means for varying said flowresistant circulation aperture, actuating means for operating said valve means, said actuating means being responsive to the speed of said engine.

2. In a hot-gas engine with a working chamber, a control system comprising a distinct chamber, means including a variable flowresistant circulation aperture open at all times for coupling said distinct chamber to said working chamber, sliding valve means for varying said flow-resistant circulation aperture, actuating means for operating said sliding valve means, said actuating means being responsive to the speed of said engine.

3. In a hot-gas engine with a working chamber, a control system comprising a distinct chamber, first means including a flow-resistant variable circulation aperture for coupling said distinct chamber to said working chamber, second means including one way fluid flow means for coupling said distinct chamber to said working chamber, third means including another one way fluid flow means for coupling said distinct chamber to said working chamber, said one way fluid flow means included by said third means being constructed and arranged to permit fluid flow in a direction opposite to that permitted by said second one way fluid flow means, selector means for selecting which one of said first means, second means, or third means operatively couples said distinct chamber to said working chamber for fluid flow therebetween, and actuating means for actuating said selector means, said actuating means being responsive to the speed of said engine.

4. In a hot-gas engine as claimed in claim 3 wherein a sealed crankcase comprises said distinct chamber.

5. In a hot-gas engine having a working chamber, a control system comprising a distinct chamber, first means including a check Valve for coupling said distinct chamber to said working chamber, said check valve being so constructed and arranged as to permit fluid flow from said distinct chamber to said working chamber only, second means including a second check valve for coupling said distinct chamber to said working chamber, said second check valve being so constructed and arranged as to permit fluid flow to said distinct chamber from said working chamber only, third means including a flow-resisting restricted passageway for coupling said distinct chamber to said working chamber and permitting fluid flow in either direction, selector means for selecting which one of said first means, said second means, or said third means operatively couples said distinct chamber to said working chamber for fluid flow therebetween, said selector means comprising a slidable valve member and actuating means for actuating said selector means, said actuator means i being responsive to the speed of said engine,

7 8 6. In a, hot-gas engine as claimed in. claim UNITED STATES PATENTS 5 wherein a sealed crankcase comprises said Number Name Date distinct chamber- 2 70 036 Eimecke Jane 1883 HERRE RINIAB EY 324,060 Woodbury et a1. e Aug. 11, I885 HEINRICH R 5 336,093 Daelen Feb, 16, 1886 REFERENCES CITED 623,137 Creuzbaur Apr. 18, 1899 The following references are of record in the file of this patent: