US3258054A - Engine preheater - Google Patents

Description

United States Patent Ofiice 3,25%,d54 Patented June 28, 1966 igan Filed June 9, 1964, Ser. No. 373,814 11 Claims. (Cl. 15828) This invention relates to preheater systems for internal combustion engines, and more particularly to arrangements for supplying fuel to a flame type preheater useful with diesel engines especially in cold climates.

Diesel engines in extremely cold climates are diflicult to start because they depend upon the heat generated only by compression to ignite the air and fuel charge in the cylinder. When the intake air is too cool, compression of such air is frequently insufficient to ignite the air-fuel mixture. Consequently, the intake air must be preheated before it is introduced to the cylinders of the engine during the periods when the cold engine is being started.

Prior to the present invention, numerous systems have been proposed for heating the intake air during diesel engine start-up; however, many such proposals are subject to one or more of the following disadvantages. First, it is desirable to introduce fuel flow to the nozzle which sprays air past an ignition device such as a coil in the intake manifold at a predetermined full flow rate and pressure without letting small quantities of fuel seep to the nozzle with inadequate pressure. Second, it is important that excess fuel flow not used by the spray nozzle be returned to the fuel supply system without leakage or other loss from the preheater system. Moreover the arrangement for returning excess fuel to the source must be subject to proper closure when the system is not operational to positively prevent leakage of supercharged air from the intake manifold through the system to the fuel source. Finally, such prior systems frequently depend upon pairs of solenoid valves which are subject to malfunction especially in colder climates. Examples of such prior systems are disclosed in Wirrer Patent 2,229,714 dated January 1941, Bakke Patent 2,717,- 586 dated September 1955, Konrad Patent 2,993,487 dated July 1961 and Baker Patent 3,024,777 dated March 1962.

Accordingly, it is an object of the present invention to provide an air preheater system free of such drawbacks.

Another object of the present invention is to provide an air preheater system for internal combustion engines including a single, self-contained valve arrangement which inherently functions automatically to admit fuel from a source to a nozzle with proper pressure and flow characteristics as well as to permit return flow of unused fuel without danger of air leakage from the nozzle to the fuel source.

Other objects and advantages of the present invention will become apparent to one skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawings,

The valve arrangement is shown in longitudinal sectional elevation in the upper portion of the drawings, and the elements of the system which cooperate with the valve arrangement to comprise the new and useful preheater system are shown in purely schematic fashion in the lower portion of the drawings to make clear their functional relationship with the valve arrangement.

Referring in more particularity to the drawings, the system comprises a valve unit formed in a unitary cast housing 12 having a stepped down threaded connection 14 at one end thereof for securing in a side wall of the intake manifold, described below, of an internal combustion engine, preferably of the compression ignition or diesel variety. The housing 12 of the valving arrangement includes a threaded conduit connection 16 communicating with a lateral inlet port 18, and a threaded conduit connection 20 communicating with a lateral outlet port 22. Formed concentrically within the threaded portion 14 is an internal generally cylindrical nozzle chamber 24 having internal threads 26 within which a nozzle, described below, is received. A valve bore 28 having three concentric stepped down sections extending longitudinally of housing 12 is provided in the other end of the unit 12 for the reception of a first shiftable valve element 30 and a second shiftable valve element 32. A port or passageway 34 concentric with the inner end of the bore 23 communicates with a mid-portion of the nozzle chamber 24, and a port of passageway 36 concentric with the nozzle chamber 24 communicates with a mid-portion of the valve bore 28, all as can be seen from the drawings.

The first shiftable valve element 30 includes a forward piston portion 38 and a rear operating stem or rod portion 40 the outer end 42 of which may take the form of a needle plunger. An O-ring type resilient valve seat 44 on the face of the piston portion 38 is adapted to close the port 34 communicating with the nozzle chamber 24 when the first valve member 30 is shifted forwardly to the left in the drawings against an annular boss 46 surrounding the inlet end of the passageway 34.

Surrounding the stem or rod portion 40 of the first valve member is a yieldable biasing means comprising a mechanical coil spring 48 adapted to bias the valve member 30 normally against the shoulder 46 to close communication between the inlet port 18 and the midportion of the nozzle chamber 24.

The second shiftable valve member 32 includes an O- ring valve seat 50 and a spring pocket 52. A yieldable biasing means such as a mechanical coil spring 54 urges the valve member 32 normally to the left in the drawing to a closed position. Longitudinal grooves 56 on the outer surface of the valve member 32 permit fluid flow from the spring pocket 52 to allow shifting of the valve 32 to the right.

The valve members 30 and 32 are positioned in the bore 23 by means of .a stationary seat member 58 having an outer annular shoulder 60 against which the righthand end of the coil spring 48 may abut. An annular boss or shoulder 62 is adapted to form with the O-ring seat 50 of the valve member 32 a closed condition preventing communication between the passage 36 and the outlet port 22. Longitudinally angled and radial-1y extending passages 64 provide communication between the valve seat 62 and the passage 36, and radially extending passages 66 provide communication between the valve seat 62 and the outlet port 22. A concentric longitudinal bore 68 in the right-hand end of the seat member 58 forms a cylinder housing in which the second valve member 32 is positioned for longitudinal shifting.

The coil spring 48 maintains the right-hand end of the seat member 58 against a closure member 70 retained in the bore 28 by a snap ring 72. The central portion of the closure member 70 is recessed to serve as a spring seat for the right-hand end of the coil spring 54 for the second valve member 32. A trio of O-ring seals 74 surrounding the piston portion 38 of the first valve member 30, the stationary seat member 58, and the end closure member 70 serve to prevent leakage in an axial direction between these respective members and the wall of the bore 23.

A nozzle member 76 including a threaded portion 78 is secured by means of the threads 26 in the nozzle chamber 24. Suitable openings, not shown, in the rear or righthand portion 80 of the nozzle are adapted to admit fuel from the passageway 34 for atomized spraying from the front or left-hand end 82 of the nozzle as indicated by the dashed line arrows 84. An overflow outlet portion 86 at the rear portion of the nozzle communicates with the passage 36 to direct excess fuel which does not flow through the nozzle back to the fuel source, as explained below. Details per se of the nozzle 76 form no part of the present invention, as the construction thereof is wellknown, and many varieties of such nozzles may be employed with the air preheating system of this invention. One characteristic of such nozzles is that they require significantly more flow to the rear end thereof than they are designed to atomize out the front end thereof; additionally, it is characteristic of such nozzles that full pressure and flow be desirably fed to the rear portion thereof without small quantities of fuel dribbling thereto at the beginning and end of each period of operation.

A source of fuel 88 may comprise a tank which conveniently may be the fuel tank for the internal combustion engine itself. Suitable conduit means 90 are provided to conduct fuel from the outlet port connection 20 to the fuel source 88. Other conduit means 92 are connected to conduct fuel from the source 88 to the inlet port connection 16 of the valve arrangement. Suitable compressor means such as the schematically illustrated fuel pump 94 are included in the inlet or feed conduit 92 to pressurize fuel from the source 88 to the nozzle 76 under suitable predetermined pressures and flow rates. If desired, a filtering device 96 may be included in the conduit 92 between the source 88 and the compressor means 94. The pressurizer or compressor 94 may be driven by suitable drive means such as an electric motor 98 connected as at 100 therewith.

An ignition device 102 may comprise a coil such as the one schematically illustrated. The coil 102 is positioned adjacent the outlet end of the nozzle 76 so as to ignite atomized fuel sprayed therefrom, in the well-known manner. A wall 104 of an intake manifold chamber 106 of an internal combustion engine is illustrated fragmentally showing the coil 102 located adjacent the outlet end of the nozzle 76. The nozzle is arranged within the housing 12 for the valving arrangement which in turn is threaded at 14 in a tapped hole 108 in the wall of the intake manifold.

A suitable power source 110 such as the battery of the internal combustion engine electrical system is connected by conductors 112 in the well-known manner to supply power to the motor 98 of the compressor 94 as well as the coil 102. A manual operating device such as a normally open spring-loaded push button switch 114 is conveniently connected in the conductor 112 to control operation of the air preheating system as desired.

In operation, the air preheater system of this invention may be operated during engine start-up to suitably preheat supercharged or pressurized air in the intake manifold of the internal combustion engine. By depressing the manual switch '114, the compressor 94 pressurizes fuel to the inlet port 18 of the valve 10, and the coil 102 serves to ignite fuel atomized from the nozzle 76. The flame created at the nozzle exit serves to suitably warm the intake air to facilitate compression combustion in diesel engines.

As the pressure in the fuel communicating with the outer annular portion of the front face of the piston portion 38 of the first valve member 30 increases in pressure, no fuel will dribble or leak to the rear portion of the nozzle until sufiicient pressure is attained to overcome the biasing force of the closure spring 48. During the following discussion, exemplary values of pressure will be mentioned solely for purposes of illustrating operation of the air preheater system of this invention, and such values are to be considered relative only and in no way limiting. For instance, the compressor 94 may pressurize fuel to a value of 100 p.s.i., and the spring 48 may be compressed or overcome by a force of, for instance, 50 p.s.i. When this latter value is reached, the piston 38 begins to shift to the right from its closed position. At this point, pressurized fuel flowing through the passage 34- to the entrance portion of the nozzle, which acts as a restriction, acts against the full front face of the piston 38 to rapidly shift the first valve member 30 to its full open position with a snap action, as can be understood.

When the valve member 30 is partly open, the needle operating end 42 thereof contacts the front face of the second valve member 32 and shifts it away from its closed position. The spring 54 of the second valve member is designed to be overcome by, for instance, 20 p.s.i. Thus, it is clear that the p.s.i acting against the full front face of the valve member 30 is sufficient to shift both valve members to the right. Shifting of the second valve member 32 to the right opens communication at the annular shoulder 62 between passage 36 leading from the rear portion 86 of the nozzle to the passage 66 in the seat member 58 leading to the outlet port 22. Thus, the overflow outlet controlled by the second valve member 32 is opened shortly after initial opening of the first valve member 38. Because the snap action of the valve member 30 is so rapid, the two valve members may be considered as acting practically simultaneously. However, it is clear that the first valve admits fully pressurized fuel at the proper flow rate to the nozzle an instant before opening of the excess overflow valve 32 to insure that fuel is moving in the proper direction through the nozzle and that no .air leaks back through the nozzle with the resultant danger of conducting air to the fuel source 88.

Once both valves 30 and 32 are in their full open position, it is clear that 100 p.s.i. fuel at the proper flow rate is directed via the passages 18 and 34 to the nozzle 76, and that excess fuel not used by the nozzle returns via passages 36, 64 and 66 and the outlet port 22 to the fuel supply 88. Continued operation of the compression motor 98 and the coil 102 maintains a continuous flame in the intake manifold 106 to heat the supercharged intake air.

Once the internal combustion engine is operating in self-sustaining fashion, release of the manual switch 114 interrupts electric power from the source 110 to the coil 102 and to the motor 98 of the fuel compressor 94. As pressure in the inlet port 18 quickly drops, the spring 48 shifts the first valve member 30 leftward to the closed position when there is still 50 p.s.i. fuel behind the nozzle 76. The second valve member 32 remains open until excess fuel in the passages 36, 64 falls below the 20 p.s.i. value at which the spring 54 shifts the second valve member 32 leftward to the closed position. Since the supercharged air in the intake manifold 106 is at an approximate value of 15 p.s.i., it will be clear that this is insufficient to open the second valve 32 when the air preheater system of this invention is not in operation.

Thus, an air preheater system has been disclosed which creates a flame by suitably igniting atomized fuel in an intake manifold of a diesel type internal combustion engine. This system is extremely simple and reliable. Well-known compressor and ignition devices are employed in cooperation with the valve arrangement 10 which insure trouble free, low cost operation. The valve arrangement 10 is an extremely simple, self-contained unit having self-cleaning features simplified by strictly mechanical operation.

While the single above described embodiment constitutes a preferred mode of practicing this invention, many other embodiments and equivalents may be resorted to within the scope of the actual invention, which is claimed 1. An intake air preheater system for internal combustion engines comprising a nozzle communicating with the air intake manifold of the engine, a source of fuel and means connected to pressurize fuel from the source to the nozzle, a valve arrangement connected to control flow of fuel from the source to the nozzle including a first shiftable member displaceable by pressurized fuel to permit flow thereof to the nozzle, a second shiftable member displaceable by shifting of the first member to permit flow of excess fuel away from the nozzle, and means restraining displacement of the shiftable members when fuel is not pressurized from the source to the nozzle.

2. An intake air preheater system for internal combustion engines comprising a nozzle communicating with the air intake manifold of the engine, an ignition device positioned in the air intake manifold adjacent the point of communication of the nozzle therewith, a source of fuel, compressor means connected to pressurize fuel from the source, a source of power, manually operable means connected to activate both the ignition device and the compressor means from the source of power, and a valve arrangement connected to open communication from the source of fuel to the nozzle upon pressurization of fuel from the source of fuel and to open communication from the nozzle back to the source of fuel until excess flow from the nozzle is interrupted.

3. An intake air preheater system as in claim 2 wherein the source of power is electrical and wherein the manually operable means is a switch normally yieldably biased to the inactive position which may be activated briefly during times such as engine start-up to preheat air.

4. An intake air preheater system for internal combustion engines comprising a nozzle having a predeteriined flow rate, means connected to pressurize fuel to the nozzle at a predetermined pressure and at a flow rate materially in excess of the predetermined nozzle flow rate, a valve arrangement connected to control flow of pressurized fuel to the nozzle including a first valve member normal-1y biased to a closed position (by a force which is overcome by the predetermined pressure to direct fuel at the excess flow rate to the nozzle, and a second valve member normally biased to a closed position by a force which is overcome by excess pressurized fuel which does not flow through the nozzle to direct such excess fuel away from the nozzle.

5. An intake air preheater system as in claim 4 wherein the first valve member includes an operating portion adapted to overcome the biasing force of the second valve member so that both valve members move from their closed positions essentially simultaneously.

6. An intake air preheater system as in claim 4 wherein the first valve member moves from its closed position with a snap action to direct flow to the nozzle only at a value near the full flow rate.

7. An intake air preheater system as in claim 4 wherein the force which biases the first valve member to the normally closed position is at least twice the force which lbiases the second valve member to the normally closed position, and wherein the latter force is sufficient to bias the second valve closed against pressures at the nozzle when fuel is not pressurized thereto.

8. An intake air preheater system valve arrangement for internal combustion engines comprising a first valve member shiftable between an open and a closed position, the open position permitting flow from a fuel inlet port to a nozzle chamber, yieldable biasing means connected to normal-1y shift the first valve member to the closed position, a second valve member shiftable between an open and a closed position, the open position permitting flow from the nozzle chamber to a fuel outlet port, and yieldable biasing means connected to normally shift the second valve member to the closed position.

9. An intake air preheater system valve arrangement as in claim 8 wherein the first valve member includes an operating portion adapted to shift the second valve member away from its closed position as the first valve member shifts to its open position.

10. An intake air preheater system Valve arrangement as in claim 8 wherein the first valve member includes a face of predetermined area only a portion of which overlies a valve port communicating with the nozzle chamber and another portion of which is exposed to the inlet port in the closed position and the total area of which is exposed to the inlet port in the open position.

11. An intake air preheater system valve arrangement as in claim 8 wherein the yieldable biasing means connected with the first and second valve members include mechanical spring devices.

References Cited by the Examiner UNITED STATES PATENTS FREDERICK KETTERER, Primary Examiner.

Claims (1)

1. AN INTAKE AIR PREHEATER SYSTEM FOR INTERNAL COMBUSTION ENGINES COMPRISING A NOZZLE COMMUNICATING WITH THE AIR INTAKE MANIFOLD OF THE ENGINE, A SOURCE OF FUEL AND MEANS CONNECTED TO PRESSURIZE FUEL FROM THE SOURCE TO THE NOZZLE, A VALVE ARRANGEMENT CONNECTED TO CONTROL FLOW OF FUEL FROM THE SOURCE TO THE NOZZLE INCLUDING A FIRST SHIFTABLE MEMBER DISPLACEABLE BY PRESSURIZED FUEL TO PERMIT FLOW THEREOF TO THE NOZZLE, A SECONG SHIFTABLE MEMBER DISPLACEABLE BY SHIFTING OF THE FIRST MEMBER TO PERMIT FLOW OF EXCESS FUEL AWAY FROM THE NOZZLE, AND MEANS RESTRAINING DISPLACEMENT OF THE SHIFTABLE MEMBERS WHEN FUEL IS NOT PRESSURIZED FROM THE SOURCE TO THE NOZZLE.

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