US3672164A

US3672164A - Independent ignition engine

Info

Publication number: US3672164A
Application number: US23368A
Authority: US
Inventors: Don B Pieper
Original assignee: WHIM Inc
Current assignee: WHIM Inc
Priority date: 1970-03-27
Filing date: 1970-03-27
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

Optimum or most economical air-fuel mixture for a turbine engine is maintained by having the fuel injection system, the ignition system and the pressure air system operate independently of the rotational velocity of the drive shaft of the engine or any of its primary rotating parts. The engine turbine and its drive shaft may be decelerated by placing a high air compression load on the drive shaft.

Description

United States Patent Pieper 1 June 27, 1972 [54] INDEPENDENT IGNITION ENGINE [72] Inventor: Don B. Pieper, Rolling Meadows, Ill. 1 73] Assignee: Whim, Inc.

122] Filed: March 27, 1970 I21 Appl. No.: 23,368

1521 u.s.c| ..60/39.3s,60/39.78,60 3981 511 1111. C1. ..F02c s/04,1=02d s 00; [58] FleldofSearch ..60/39.81,39.8,

56 References Cited UNITED STATES PATENTS 2,273,406 2/1942 Lasley ..60/39.38 2,129,691 9/1938 Hazwarth ..60/39.79 2,003,292 6/1935 Hazwarth ..60/39.79 8/ l 950 Anderson ..60/39.8

2,112,672 3/1938 Lasley ..60/39.38

FOREIGN PATENTS OR APPLICATIONS 418,184 10/1934 Great Britain ..60/39.79

449,1 15 6/1936 Great Britain ..60/32 M Primary Examiner-Benjamin W. Wyche Assistant ExaminerWarren Olsen Attorney-Mason, Albright and Stansbury 57 ABSTRACT Optimum or most economical air-fuel mixture for a turbine engine is maintained by having the fuel injection system, the ignition system and the pressure air system operate independeritly of the rotational velocity of the drive shaft of the engine or any of its primary rotating parts. The engine turbine and its drive shaft may be decelerated by placing a high air compression load on the drive shaft.

1 1 Claims, 5 Drawing Figures INDEPENDENT IGNITION ENGINE The present invention refers to an engine wherein the fuel injection system, ignition system, and pressure air system operate independently of the rotational velocity of the drive shaft of the engine or any of its primary rotating parts.

In a conventional internal combustion gasoline engine utilizing a fuel injection system, valves are opened by a cam shaft attached to the main drive shaft to inject fuel into the cylinders and to allow the exhaust gases to escape. A distributor is connected to the main drive shaft to fire the combustible mixtures in the chambers. Thus, the rate of fuel injection and ignition in the cylinders or firing chambers of an internal combustion gasoline engine depend upon the rotational velocity of the main drive shaft. In diesel engines of the type not requiring spark ignition, a high pressure fuel pump device is connected to the main drive shaft to time the repetition rate of the fuel injectors to the rotational velocity of the main drive shaft. In ram jet engines and in turbo jet engines, fuel burning is continuous and if there is variable control it is accomplished by varying the amount of fuel being injected into the firing chamber per unit time. In all these normally conventional engines, the air-fuel ratio must necessarily vary with the desired torque of the drive shaft and thus a constant predetermined air fuel ratio cannot be maintained at alloperating speeds.

For every combustible fuel used in these various engines there is a best air-fuel ratio for the most complete combustion of the fuel, which reduces to a minimum undesired pollution of the air by the release of unburned hydrocarbons to the surrounding atmosphere. The most economical air-fuel mixture for each of these engines is usually different from the others. However, in order to achieve either the most economical airfuel mixture or the most completely combustible air-fuel mixture, it is necessary to maintain the ratio of air to fuel in the mixture. at a predetermined constant ratios The present invention provides means for setting the airfuel mixture at a substantially constant ratio for all speeds of the drive shaft, for all speeds of the fuel injection system, and for all speeds of the ignition system. A separate control provides and governs the repetity of the operation of the fuel injection system and the ignition system.

Thus, an object of the present invention is to provide a new and improved engine.

Another object is to provide an engine wherein the torque on the drive shaft and the output horsepower of the engine is controlled by the repetitive frequency of the fuel injection and ignition systems.

An additional object is to provide an engine wherein the operations of the fuel injection and ignition systems are independent of the rotational velocity of the main drive shaft and independent of any other primary driving parts of the engine.

Still another object is to provide an engine that does not require a lubricating system.

Yet another object is to provide an engine which does not require a liquid cooling system and fan.

A further object is to provide an engine which utilizes a constant optimum productive fuel-air mixture at all ranges of velocity.

A still further object is to provide an engine which uses fuel only when it is required to produce work.

Still another object is to provide a high acceleration turbinetype engine.

An important object is to provide an engine wherein the combustion chambers are purged of exhaust gases without the use of complicated and expensive valves.

Another additional object is to provide an exhaust turbine with'an engine which recovers part of the energy in the exhaust gases.

Another additional object is to provide a method of storing kenetic energy obtained in a forced deceleration by conversion to pressure air for use in the next acceleration of a vehicle.

Another additional important object is to provide an engine having smooth acceleration in a wide range of speeds.

A still further object is to provide an engine that does not require an automatic transmission with heavy heat energy losses.

Still another object is to provide an engine with a minimum of machined and lubricated parts in combustion areas.

Further objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of a preferred embodiment of my invention;

FIG. 2 is a partially broken away cross sectional end view of the turbine portion of my preferred embodiment illustrated in FIG. 1;

FIG. 3 is an elevational view of the turbine portion illustrated in FIG. 2 taken along the line 3-3;

FIG. 4 is an exploded view of a single combustion chamber of the turbine illustrated in FIGS. 2 and 3; and

FIG. 5 is a partial sectional view of the combustion chamber illustrated in FIG. 4 taken generally along the line 5-5.

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail, an embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Referring to FIGS. 1 3, a turbine 10 has six combustion chambers 11 16 mounted on a rotor housing 19. A shaft 20 is rotatably mounted in

bearings

21 and 22 which are mounted on the rotor housing 19. A turbine rotor 23 is rigidly mounted on the shaft 20 for rotation therewith. A series of turbine blades generally indicated as 24, r are mounted on the periphery of the rotor 23 in the conventional manner well known to those skilled in the art. 1

Referring to FIG. 1, an air compressor 30, which may be of any conventional type well known to those skilled in the art, has an air intake 31 mounted thereon to receive atmospheric air and has a compressor drive shaft 32 rotatably mounted therein. The air compressor shaft 32 is driven by the turbine shaft 20 through a pulley 33 rigidly mounted on one end of shaft 20, a drive belt 34 and a forward engaging clutch type pulley 35 mounted on the compressor shaft 32. A compressed air output port 36 of the compressor 30 is connected to a demand pressure control manifold 37 by a compressed air line 38 to supply compressed air to the manifold 37. The demand pressure control manifold 37 is connected by a high pressure air line 39 to an air accumulator tank 40for the purpose of supplying compressed air to the accumulator tank. Manifold 37 is connected to a relief valve 155, which is connected through a shut-off valve 151 to a vent 153, and to a high pressure relief valve 154. High pressure air from the accumulator tank 40 is supplied to each of the combustion chambers 1 1-16 and thereby to the entire turbine housing 19 through a high pressure line 41, a valve 42, a high pressure line 43, a pressure regulator 44, and a high pressure air manifold 45 connected to each of the respective firing chambers 11-16. Pressure in-the turbine housing 19 is controlled by a pressure release valve 47 which is preset to open at a pressure slightly below the release pressure setting of pressure regulator 44.

Two alternative methods for aiding the driving of the compressor 30 are provided in addition to the direct drive from the turbine shaft 20. An exhaust line 46 connects an exhaust port 26 of the turbine 10 to the input side of the pressure release valve 47. An output side of the pressure release valve 47 is connected to a conventional exhaust turbine 50 by an exhaust gas line 48. An output drive of the exhaust turbine 50 (not shown) is connected to the compressor shaft 32 by a one way forward clutch coupling generally indicated at 49. Exhaust gas from the exhaust turbine 50 is expelled through an exhaust gas line 51.

An electric compressor drive motor 52, large enough to turn the compressor unassisted, has an output drive shaft 53 with a pulley 54 rigidly mounted thereon. Compressor shaft 32 has a one way clutch coupling 55 with a drive pulley 56 incororated therein for driving the shaft 32 through the coupling 55 when the electric compressor motor 52 is energized. A drive belt 57 connects the pulleys 54 and 56.

A pressure operated electrical switch 60 is mounted on the accumulator tank 40 so that a pair of contacts are closed when the pressure in the accumulator tank 40 falls below a predetermined value. The motor 52 is connected to the switch 60 by an electrical conductor 64. Switch 60 is connected to a terminal 65 of a storage battery 66 by a conductor 67. The storage battery 66 may be of any conventional design well known to those skilled in the art and may, for example, provide 12 volts of potential between a grounded terminal 68 and the terminal 65. The electrical motor 52 is connected to circuit ground in order that the battery 66 may be connected across the motor 52 to energize it whenever the switch 60 is closed. Thus, three sources of energy to turn the compressor are evidenced. Each is connected to compressor shaft 32 with a forward clutch type pulley so that the effort exerted can be alternate combinations of torque forces. At constant operating speed the exhaust turbine 50 and the turbine shaft will turn compressor 30. But, it should be noted that motor 52 and exhaust turbine 50 can take over, assuring demand air volume irrespective of the speed of turbine shaft 20.

A fuel and firing system generally indicated within the dash line 70 operates completely independently of the speed of the turbine rotor 23 and the turbine output shaft 20. An accelerator pedal (or lever) of any conventional design well known to those skilled in the art 71 is connected through suitable mechanical linkage 72 to the high pressure air valve 42. An electrical motor 73 and a rheostat 74 having a slide 75 are connected in series across the

terminals

65 and 68 of battery 66 by the electrical conductors 76, 77 and 78, respectively. The position of the slide 75 of the rheostat 74 is controlled by the position of the accelerator pedal 71 through connecting mechanical linkage 79. Therefore, the position of the accelerator pedal 71 controls the speed of rotation of the motor 73.

A fuel and ignition distributor unit 80 has a drive shaft 81 rotatably mounted therein. A high pressure fuel pump having six compression pump chambers is mounted in the unit 80 and driven by the shaft 81 so that fuel is pumped through a set of six fuel line 90 to each of a set of injectors 87 mounted on the respective combustion chambers 11 16 so that fuel is supplied to the injectors sequentially at a rate determined by the speed of rotation of the drive shaft 81. The drive shaft is driven by the motor 73 through the motor output pulley 82, a belt 83, and a pulley 84 rigidly mounted on shaft 82. A fuel tank 85 is connected bya fuel line 86 to the input side of the pump in unit 80. An electric distributor is also mounted in the unit 80 and connected to the drive shaft 81 to be driven thereby. An electrical output harness 89 connects the distributor to a spark plug or ignitor such as 88 mounted in the wall of each of the respective chambers 11 16. The connections of the pump and the distributor are such that immediately after fuel is sequentially introduced in each of the chambers 11 16 an ignition spark is provided by the spark plug or ignitor in each of the respective firing chambers to ignite the fuel mixture. During the operation of the engine, high pressure air is supplied at all times to the respective firing chambers and, therefore, is available to produce a combustible mixture and to aid in purging of the tired chambers of exhaust gases after each cumbustion. The air regulator 44 keeps the pressure introduced in the chambers by the air manifold 45 at a constant pressure and the fuel pump of distributor unit 80 delivers a given amount of fuel to each chamber regardless of the seed of rotation of the drive shaft. Therefore, a constant fuel-air mixture may be maintained. This fuel-air mixture, being constant, may be set at the optimum fuel-air ratio for the most complete combustion so that the harmful exhaust products of the exhaust gas from the turbine are reduced to a minimum.

Referring now to FIGS. 2, 3, 4 and 5, each chamber has a port 91 96 m the side of each firing chamber angled toward the nozzle. These are each in turn connected through gas conduits 101 106 to a ring tube 100. When combustion occurs in any given firing chamber the efiect, due to ventouri action, is to draw air or exhaust from the respective attached gas conduit which in turn tends to reduce the internal pressure in the ring. Because of the tendency to equalize this lowered pressure some exhaust will be purged or drawn from each of the other chambers as indicated by the arrows in FIG. 3. When a chamber is fired the purging of exhaust will be substantially complete with fresh air replacing the exhaust gases through one way valve 111 116 and the pressure air inlet 121 126. Increasing the firing rate tends to lower the internal ring pressure and make purging of chambers more rapid.

An electrical generator is connected to shaft 20 to be driven thereby through a pulley 131 rigidly mounted on shaft 20, a drive belt 132 and a pulley 133 and a generator drive shaft 134. The electrical output of the generator is connected to battery 66 through a conductor 135, a voltage regulator 136, a conductor 137 and a grounded conductor 138. The shaft 20 is connected to a conventional transmission 140 which may be of any type well known to those skilled in the art. It may be of either the mechanical gear type or a fluid drive type. The transmission 140 has an output drive shaft 121 to be connected to suitable driving wheels or tracks of a land vessel, the propellor of an aircraft, the propellor or fluid drive pump of a vessel or to the input drive shaft of stationary machinery.

An alternate form of firing chamber may be utilized in the turbine 23. Rather than utilizing the ring purging system, a valve exhaust port may be provided which is opened subsequent to combustion in each chamber which allows the exhaust gases to be removed under the pressure of incoming air from high air pressure manifold 45.

Those skilled in the art will recognize that the present invention may be utilized in many varying forms. All such forms are intended to be within the scope of the appended claims. For example, either one or a large multiplicity of firing chambers may be employed. Either the ring 100 exhaust purging system shown in FIGS. 2, 3, 4 and 5, the exhaust system set forth in the previous paragraph, or neither of these may be utilized relying upon only the high pressure air to force excess gases out through the nozzles and into the turbine blades. Various voltage electrical systems may be utilized and other auxilliary drive systems, such as hydraulic systems may be employed to drive such motors as motor 52 and motor 73.

The braking system illustrated in FIG. 1 is substituted for conventional braking systems. Referring now to FIG. 1, a brake pedal is connected to a shut-off valve 151 by a mechanical linkage 152, closing off an over demand release vent 153. Because shaft 20 would continue to turn compressor 30 on the deceleration of a vehicle, an increasing volume and pressure would be added to the accumulator tank 40. THis would tend to slow a vehicle by converting kinetic energy to static energy in the form of increased air pressure which is stored for the next start. Further depression of brake pedal 150 would engage conventional braking shoes (not shown) if needed. An extreme high pressure relief valve 154 is provided.

Referring now to FIGS. 1 through 5 of the drawings, the

operation of the preferred embodiment of the invention illustrated in the figures will be described in greater detail. In order to start the engine, the accelerator pedal 71 is slightly depressed opening shut-off valve 42 to allow air from the accumulator tank 40 to flow through the pressure regulator 44. The output pressure from regulator 44 is held by the regulator at 90 psi. This air flows through combustion chambers 11 16 and finally against the turbine blades 24 causing the turbine to commence to rotate. At the same time that air begins entering the combustion chambers 11 16, the foot accelerator has operated slide 75 to allow current to commence flowing through the rheostat 74 energizing the motor 73 to run at a low speed. This causes the distributor unit 80 to provide fuel and electrical ignition to the cylinders sequentially. The order of charging and firing the combustion chambers is not critical, but it is believed desirable to fire cylinders which are approximately opposite to each other. in other words, a sequence which might begin with chamber 11, followed by chamber 14, chamber 12, chamber 15, chamber 13, and chamber 16. If desired, all six chambers could be fired at once, but under this situation all of the residual burnt gases in the chambers would have to be expelled by the fresh air coming from the manifold 45. As the accelerator pedal 71 is further depressed, it moves a slider 75 on rheostat 74 to increase the speed of motor 73 whereby increasing the number of firings of the chambers 11 16 per unit time. Thus, the pressure on the turbine blades is kept at a higher average level increasing the speed of the turbine rotor.

As aforementioned, there are three methods of maintaining sufficient pressure in the accumulator tank 40 to insure that the engine will have at least the required 90 psi in the air manifold 45. At low speeds the direct drive from the turbine shaft 20 to the compressor shaft 32 drives the compressor 30. As the rotational speed of the turbine increases, the pressure of the exhaust gases in the line 46 increases to the point that the relief valve 47 opens allowing the exhaust gases to operate the turbine 50. Thus, the exhaust gases themselves through the one way clutches 49 will be driving the shaft 32 as the turbine speed increases reducing the torque that must be supplied by the shaft 22 to a zero value so that the shaft 22 is then applying all of its available torque to the transmission 140. The compressor under such conditions provides a pressure of approximately 125 psi to the demand pressure control manifold 37. However, the pressure relief valve 155 will open at a pressure of lOO psi, thereby preventing the pressure in the acculator 40 from exceeding approximately 100 psi. Since the shut-off 150 is normally open, air passing through the relief valve 155 escapes easily through the vent 153. ln starting the unit, after the turbine has been shut down for a long period of time, there may not be sufficient pressure in the accumulator tank 40 to operate the regulator valve 44. However, the switch 60 is activated whenever the pressure in the tank falls below 90 psi to energize the motor 52 which will operate the compressor 32 to build up the pressure in the accumulator tank. Thus, there is available sufficient air to start the turbine, and with this air, the firing chambers commence to fire immediately upon the operation of the foot pedal 71 because the firing rate is completely independent of the speed of the drive shaft 20.

As aforementioned, the compressor and accumulator tank can be utilized to slow down the turbine. With the combustion chambers not firing, the exhaust turbine 50 slows down and the compressor is driven by the shaft 20 through the belt 34 placing a load on the shaft 20 tending to bring it to a stop. This slowing of the shaft 20 is further increased by the operation of the brake pedal 150 which closes shut-off valve 151 forcing the pressure in the accumulator tank to increase to 175 psi. The compressor attempts to provide increasing pressure and thereby puts a greater demand on the turbine shaft 20. if the pressure in the tank 40 and the connecting line 38 reaches 175 psi the release valve 154 will open to prevent the pressure in the system from exceeding 175 psi.

The constant source of air pressure allows the ratio of fuel to air to be held at substantially a constant value. This is a ratio which has been selected for the most complete burning of the fuel, and, therefore, the least possible production of unwanted exhaust by-products such as hydrocarbons.

1 claim:

1. An engine comprising:

a. a housing,

b. a drive shaft rotatably mounted in said housing,

c. a turbine rotor having turbine blades and rigidly mounted on said drive shaft,

d. at least one combustion chamber mounted on said housing having an exhaust nozzle directing exhaust gases against said turbine blades,

e. means for injecting air into said combustion chamber,

f. means for injecting fuel into said combustion chamber at periodic intervals, to produce a fuel and air combustible mixture at said periodic intervals, g. means for igniting said combustible mixture at said periodic intervals, and h. means for starting, stopping and varying the rotational speed of said drive shaft including 1. a variable speed electric motor mechanically connected to drive said fuel injection means and mechanically connected to drive said igniting means at variable frequencies of said periodic intervals and 2. control means connected to said motor for energizing, deenergizing and varying the operating speed of said motor.

2. An engine in accordance with claim 1, wherein said means for injecting air into said combustion chamber comprises:

a. an accumulator tank,

b. a pressure regulator connected between said tank and said combustion chamber to deliver air to said combustion chamber at a constant pressure, and

c. a compressor connected to said accumulator tank to raise the air pressure in said tank to a valve grater than the pressure regulated by said pressure regulator.

3. An engine in accordance with claim 2, wherein said compressor is connected to be driven by an electric motor which is energized by an electrical pressure switch that is mounted on said tank to determine the interval air pressure of said tank.

4. An engine in accordance with claim 2, wherein said compressor is connected to be driven by said turbine drive shaft.

5. An engine in accordance with claim 2, wherein said compressor is connected to be driven by another exhaust gas turbine that is connected to said housing through a pressure re gulator to receive exhaust gases from said housing at a predetermined pressure.

6. An engine in accordance with claim 1, wherein said means for injecting fuel into said combustion chamber, comprises:

a. a source of fuel,

b. a fuel pump connected to be driven by said variable speed motor and connected to said source of fuel to pump at said periodic intervals a predetermined quantity of fuel,

c. an injector mounted on each said combustion chamber,

and,

d. a fuel conduit connecting said pump and each said combustion chamber to inject fuel into each said combustion chamber at said periodic intervals.

7. An engine in accordance with claim 6, wherein said control means connected to said motor comprises a variable resistance connected in series with a'source of electrical potential and said variable speed motor to vary the rotational velocity of said motor.

8. An engine in accordance with claim 1, wherein said means for igniting said combustible mixture at said periodic intervals comprises:

a. an ignitor mounted in each combustion chamber, and

b. an electrical distributor connected to be driven by said variable speed motor and having a rotor periodically contacting each ignitor.

9 An engine in accordance with claim 8, wherein said means for injecting fuel into said combustion chamber, comprises:

a. a source of fuel,

b. a fuel pump connected to said source of fuel to pump at said periodic intervals a predetermined quantity of fuel, said pump being driven by said variable speed motor,

c. an injector mounted on each said combustion chamber,

and

d. a fuel conduit connecting said'pump and each said combustion chamber to inject fuel into each said firing chamber at said periodic intervals.

10. In an engine as specified in claim 1:

a. a multiplicity of combustion chambers,

b. a port adjacent the nozzle of each combustion chamber,

and

into said at least one combustion chamber whereby the ratio of fuel and air in said combustible mixture remains constant at a predetermined value regardless of the frequency of said periodic intervals.

Claims

1. An engine comprising: a. a housing, b. a drive shaft rotatably mounted in said housing, c. a turbine rotor having turbine blades and rigidly mounted on said drive shaft, d. at least one combustion chamber mounted on said housing having an exhaust nozzle directing exhaust gases against said turbine blades, e. means for injecting air into said combustion chamber, f. means for injecting fuel into said combustion chamber at periodic intervals, to produce a fuel and air combustible mixture at said periodic intervals, g. means for igniting said combustible mixture at said periodic intervals, and h. means for starting, stopping and varying the rotational speed of said drive shaft including 1. a variable speed electric motor mechanically connected to drive said fuel injection means and mechanically connected to drive said igniting means at variable frequencies of said periodic intervals and 2. control means connected to said motor for energizing, deenergizing and varying the operating speed of said motor.

2. control means connected to said motor for energizing, deenergizing and varying the operating speed of said motor.

2. An engine in accordance with claim 1, wherein said means for injecting air into said combustion chamber comprises: a. an accumulator tank, b. a pressure regulator connected between said tank and said combustion chamber to deliver air to said combustion chamber at a constant pressure, and c. a compressor connected to said accumulator tank to raise the air pressure in said tank to a valve grater than the pressure regulated by said pressure regulator.

5. An engine in accordance with claim 2, wherein said compressor is connected to be driven by another exhaust gas turbine that is connected to said housing through a pressure regulator to receive exhaust gases from said housing at a predetermined pressure.

6. An engine in accordance with claim 1, wherein said means for injecting fuel into said combustion chamber, comprises: a. a source of fuel, b. a fuel pump connected to be driven by said variable speed motor and connected to said source of fuel to pump at said periodic intervals a predetermined quantity of fuel, c. an injector mounted on each said combustion chamber, and, d. a fuel conduit connecting said pump and each said combustion chamber to inject fuel into each said combustion chamber at said periodic intervals.

7. An engine in accordance with claim 6, wherein said control means connected to said motor comprises a variable resistance connected in series with a source of electrical potential and said variable speed motor to vary the rotational velocity of said motor.

8. An engine in accordance with claim 1, wherein said means for igniting said combustible mixture at said periodic intervals comprises: a. an ignitor mounted in each combustion chamber, and b. an electrical distributor connected to be driven by said variable speed motor and having a rotor periodically contacting each ignitor. 9 An engine in accordance with claim 8, wherein said means for injecting fuel into said combustion chamber, comprises: a. a source of fuel, b. a fuel pump connected to said source of fuel to pump at said periodic intervals a predetermined quantity of fuel, said pump being driven by said variable speed motor, c. an injector mounted on each said combustion chamber, and d. a fuel conduit connecting said pump and each said combustion chamber to inject fuel into each said firing chamber at said periodic intervals.

10. In an engine as specified in claim 1: a. a multiplicity of combustion chambers, b. a port adjacent the nozzle of each combustion chamber, and c. manifolds means connecting two or more said ports.

11. An engine as specified in claim 1, wherein said means for injecting air includes pressure regulator means to deliver air into said at least one combustion chamber at a predetermined pressure and said means for injecting fuel includes quantity measuring means to deliver equal quantities of fuel into said at least one combustion chamber whereby the ratio of fuel and air in said combustible mixture remains constant at a predetermined value regardless of the frequency of said periodic intervals.