US3796207A

US3796207A - Catalytic tank heater for engines

Info

Publication number: US3796207A
Application number: US00145616A
Authority: US
Inventors: E Olson
Original assignee: Walbro Corp
Current assignee: Walbro Corp
Priority date: 1971-05-21
Filing date: 1971-05-21
Publication date: 1974-03-12
Anticipated expiration: 1991-03-12

Abstract

A catalytic tank heater for internal combustion engines which uses vaporized gasoline as a combustion fuel. The vaporized gasoline is air aspirated by air flow through a venturi onto a tubular catalytic heat producing reactor element to produce heat for heating the cooling liquid of an engine. The heater is efficient, and includes a electric heater element that preheats the catalyst, and also initially vaporizes the fuel, in order to obtain ignition of the catalytic heater automatically.

Description

United States Patent n91 @lson CATALYTIC TANK HEATER FOR ENGINES [75] Inventor: Ellis W. Olson, Eden Prairie, Minn.

[73] Assignee: Walbro Corporation, Cass City,

Mich.

[22] Filed: May 21, 1971 [21] Appl. No.: 145,616

[52] US. Cl. 123/1425 R, 23/288 J [51] Int. Cl. F02n 17/02 [58] Field of Search 123/142.5 R; 23/288 J [56] References Cited UNITED STATES PATENTS 2,737,169 3/1956 Kimberlin l23/l42.5 R

2,013,707 9/1935 Williams 23/288 J 2,118,567 5/1938 Milas et al. 23/288 J 3,400,700 9/1968 Lindsey et al 123/1425 R [451 Mar. 12, 1974 1,957,254 5/1934 Eymann 23/288 J Primary Examiner-Laurence M. Goodridge Assistant ExaminerCort Flint Attorney, Agent, or FirmBarnes, Kisselle, Raisch &

Choate [57 ABSTRACT A catalytic tank heater for internal combustion engines which uses vaporized gasoline as a combustion fuel. The vaporized gasoline is air aspirated by air flow through a venturi onto a tubular catalytic heat producing reactor element to produce heat for heating the cooling liquid of an engine. The heater is efficient, and includes a electric heater element that preheats the catalyst, and also initially vaporizes the fuel, in order to obtain ignition of the catalytic heater automatically.

2 Claims, 3 Drawing Figures ENG/NE 6/15 0!. [NE TANK PMENFEWHMM EJ962071 ENG/1W5 J GASOLINE TANK 25 50 INVENTOR.

7* 7 ELL/5 w OLSON 3 PUMP y I m r; I 4T7'0/F/UEV5 1 CATALYTIC TANK HEATER FOR ENGINES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tank heater for use for heating the liquid coolant of an internal combustion engine and more particularly a tank heater which has a catalytic heating element.

2. Prior Art In prior art there are a number of different types of tank heaters for use in automobiles. For example, US.

Pat No. 2,737,169, and 2,632,511 show examples of typical tank heaters. In addition, catalytic heaters are used for devices such as tent heaters. Typical examples are shown in US. Pat. Nos. 3,240,256, and 3,457,021.

In addition, a resistance wire heating element positioned in a catalytic element is shown in US. Pat. Nos. 3,l99,505, and 3,291,199.

qw v there, i n a k hea er f9ULS w' t liater: nal combustion engines which vaporizes the same fuel as the engine, and which includes an air aspiration venturi for insuring proper distribution of fuel vapor across the catalytic heating element.

SUMMARY OF THE INVENTION The present invention relates to a catalytic tank heater for use with liquid cooled internal combustion engines. The tank heater has a means for circulating the engine coolant through a jacket, and a heating element comprising an annular sheath of catalytic material. The fuel utilized may be the fuel supply for the engine such as gasoline or LP. gas (propane or butane). When gasoline is used, a fuel vaporizing tube is embedded in the catalytic material so that the heat from the heat element will vaporize the fuel. The fuel is discharged through a control orifice inside a venturi that is located so that the air flowing through the venturi is moving along the axis of the annular catalytic element. The venturi action properly distributes and disperses the fuel through air aspiration and also insures that the fuel is completely combined with air.

The fuel is supplied initially in response to a thermostat or sensor which is located to be operated in response to the temperature of the heater. As specifically shown the fuel is supplied by an electric fuel pump, which uses the gasoline supply from the automobile tank. With LP. gas, the fuel pump is replaced with a solenoid control valve. Various types of fuel pumps which operate in response to the temperature of the catalytic reactor, or temperature of the output air from the reactor could be used if desired.

The device further includes a preheater of electric resistance wire embedded in the catalytic reactor which will initially heat the reactor, cause the reactive, flameless combustion and also preheat a vaporizer tube for the gasoline.

The venturi aspirator, together with the preheated evaporator tube permits the use of gasoline as a fuel, and obtains the desirable features of a flameless heater or heat source in an internal combustion engine coolant heater.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a tank heater made according to the present invention;

FIG. 2 is a sectional view taken as on line 2-2 in FIG. 1; and

FIG. 3 is a simplified schematic representation of the operating circuit for the heater of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT A engine tank heater illustrated generally at 10 is used in a conventional manner for heating the coolant from an engine, illustrated only with a block 11. The engine is the usual internal combustion engine having a liquid coolant for the engine. In colder climates, starting of internal combustion engines in automobiles, trucks or the like is difficult in cold weather, and one way of insuring that the engine will start easily is to keep the liquid coolant warm, or to warm the liquid coolant prior to an attempt to start the engine. Not only will the engine start easier, but it is an aid in prolonging engine life. The preheating warms the oil and makes sure that the proper lubrication occurs as soon as the engine starts.

The tank heater illustrated generally at 10 is mounted under the hood. of an automobile or truck or on a stationary engine. Suitable hoses are used for connecting the heater to an inlet from a side low down on the engine block. The outlet of the heater assembly can be connected to a high location on the engine block. Usually the tank heater outlet will be connected adjacent connections for the heater for warming the interior of the vehicle. The inlet of the tank heater will be lower than the outlet so that the warmed water will rise and cause a circulation through the tank heater. Suitable mounting brackets are provided, and the heater will be positioned where combustion air can circulate.

As shown, the tank heater has an outer jacket 12 which is cylindrical in shape, and a spaced liner wall 13 which is concentric with the outerjacket 12 and spaced inwardly therefrom. This forms a heat exchange chamber 14 between the two

walls

13 and 14. This chamber 14 is sealed at its ends with a first cap 15, and a second lower cap 16 to form a liquid tight coolant chamber which is an annular chamber made up of the wall I2 and 13, and sealed at its opposite ends.

The chamber 14 has an inlet pipe 17, with a ball check valve 18 therein. The pipe 17 is the inlet for liquid which will fill the chamber 14. An outlet pipe 2l is provided for permitting warmed liquid to flow out of the chamber. The check valve insures that there is no reverse flow through the unit when the engine is runnmg.

A central annular chamber illustrated generally at 22 inside the liner wall 13 forms the flameless combustion reaction area for the tank heater. As shown, a pair of annular, cylindrical perforated baffle walls 23 and 24 (these can be made of an expanded metal or screening) are fastened to the bottom cap 16 for the chamber 14, and extend downwardly therefrom. A support cap 25 is suitably attached to the ends of these

walls

23 and 24.

At the upper end of the tank heater 10 there are a pair of cylindrical

exhaust baffle walls

26 and 27 which are also perforated, and spaced from each other and which are attached to the end cap 15 for the chamber 14. A solid end cap 28 is attached to the outer ends of the

walls

26 and 27. A gasket 28A of asbestos can be used for electrical and heat insulation of the cap 28. The end cap 28 is used to mount an upper catalytic reactor support 31, and the end cap 25 is used to mount a lower catalytic reactor support 32. The catalytic material illustrated generally at 33 for the reactor is formed into an annular band and is supported between the end caps 31 and 32 in any suitable manner. This can be with a screen, if necessary, or if the catalytic reactor material is sufficiently strong it can be merely supported between the two

support members

31 and 32. The catalytic burner material can be a loose stranded ceramic material formed into a cylinder and then impregnated with a platinum compound for a catalyst. The reactor or catalytic element material is well known in the art.

A resistance heating element 35 is extended between the

supports

31 and 32 and is mounted on insulating clips 36. The heating element 35 is embedded in the reactor material, and is wound back and forth between the two

supports

31 and 32 on clips 36 which are spaced annularly around the reactor, so that the resistance heating element 35 forms a number of zig zag bends back and forth between the

supports

31 and 32, and also goes around the reactor. The cross sections of the resistance heating element 35 are shown in FIG. 2.- One end of the resistance heating element is connected to a suitable power supply, and the other end is grounded to the case of the tank heater in a suitable manner. This will be shown in the electrical schematic.

At the lower end cap 25, there is an annular venturi member 40 mounted. The inlet of the venturi member 40 is surrounded by a housing 41 and inlet openings 42 are provided to permit air to flow into the bottom of the venturi 40 and move upwardly. The upper end of the venturi opens into an open center chamber 43 that is surrounded by the cylindrical catalytic reactor.

A fuel evaporator tube 44, which is bent into an inverted U shape, is embedded into the reactor material on one side thereof and extends part way up the reactor. The evaporator tube 44 has a downwardly extending leg that ends in a J-shaped bend portion 45, and at the outlet of the bend there is a fitting 46, which has an orifice of suitable size. The orifice is centered with the venturi 40, and is positioned just below the venturi. A suitable clip 47 can be used for fastening the evaporator tube in place on cap 25.

A fuel pump 50 is connected to a gasoline supply, indicated at 51, which may be the main tank for the vehicle with which the heater is used, or may be a separate tank if desired. The gasoline is the same gasoline utilized for powering the vehicle engine. The fuel pump needs to be only a very low volume pump and the orifice in the outlet of the evaporator controls flow. In operation, for a standard automobile engine, about one quart of gasoline is used in 18 hours of operation. Different size heaters or engines would use different amounts of fuel. The pump can be a pulsating pump that operates on a small amount of power.

Referring to FIG. 3, a schematic representation of the electrical circuit used for operation of the device is shown. A power supply is indicated at 52, and a main power on switch 53 is used for controlling power to the circuit. The power supply 52 would be the vehicle battery or any other desired power source, such as separate nickel cadmium batteries, or rechargeable batteries. In addition, in the circuit there is a timer switch indicated at 54. This would be a variable time switch of usual design, but generally minutes for the purposes of this particular invention has been found to be satisfactory, although the time on could be changed. The electric resistance element 35 is shown in circuit, and a thermostat 55 or other temperature sensor, having a switch is connected in circuit and leads to the electric fuel pump 50. The connection from the other side of the fuel pump leads back to the main line between the timer and the main switch. The thermostat or sensor 55 is positioned between the fuel pump and ground connection, and it can be noted that the circuit for the fuel pump is such that when the thermostat switch is closed, if main power switch 53 is closed, fuel pump 50 will be energized even if the timer switch 54 is open. The fuel pump 50 is an electrically operated fuel pump commonly used in automobiles.

The thermostat 55 is made so that the switch will not close until the temperature at the thermostat has reached a particular level. The thermostat 55 is shown in position adjacent the clamp 47 by the evaporator tube. Thus the thermostat senses the heat from the reactor, but is not mounted directly on the reactor.

When the temperature at the thermostat, adjacent this evaporator tube reaches a preselected level, the thermostat switch will close and the fuel pump will be energized. This will pump gasoline from the tank 51 through the evaporator tube, and will do so only when the unit has been heated to a preselected temperature.

When the heater is to be used, and is installed in a vehicle the main power switch 53 is turned on. Also the timer switch 54 is closed, for example for a period of 15 minutes or other desired time period. This will energize the resistance heater 35 from the power supply 52 and as the heater 35 heats, because it is distributed around the catalytic reactor material 33, it will bring the reactor material up to a preselected temperature. At the same time, it will heat the evaporator tube 44, and the evaporator tube will get quite warm to tend to evaporate any liquid fuel that is in the tube 44.

After the thermostat reaches its operating temperature because of the heat from the resistance heater 35, the fuel pump will be turned on by closing of the thermostat switch and a supply of gasoline will be pumped into the evaporator tube, and out through the nozzle 46.

Because the resistance heater 35 will raise the temperature of the reactor, which surrounds the cavity 43, air will rise and pass into the opening 42, and will flow as indicated by the arrow 57 past the orifice member 46 of the evaporator tube 44 through the venturi member 40. The fuel will be in its gaseous state when it flows from orifice member 46. The fuel will mix with the air flowing through the venturi. The flow through the venturi of course increases the air velocity and when the air flows into the central cavity 43-the pressure is thus increased as the air slows down. The increased pressure in cavity 43 causes the air fuel mixture to be forced through the catalytic reactor material. The catalytic reactor material will be hot because of the heat from resistor wire 35. in the presence of the catalyst the fuel will react chemically causing heat to be generated flamelessly. The air coming in through the venturi 40 will pass through the catalytic reactor material 33 outwardly into the space between the wall 13 and the outer surfaces of the catalytic material will be heated by the chemical reaction at the catalytic reactor. This heated air will also tend to rise and will also combine with any excess fuel at the surface of the catalytic reactor. The heated air will cause convection currents coming in through the

walls

23 and 24, around the outer surfaces of the catalytic material, and then out through the

walls

26 and 27. The heat generated by the reaction at the catalytic material will heat the wall 13, and of course this will transfer heat to the liquid in the chamber 14.

The heating process will continue, until the main switch 53 is turned off. The heat of tube 44 will evaporate the gasoline, and the gaseous form (as used herein, vapor) of the fuel will pass through the orifice member 46, and the venturi action causes rapid movement of air past the orifice to insure adequate mixing of the evaporated fuel vapor and transfer of the fuel vapor into the interior of the tubular catalytic material 33. The flameless combustion will continue and the reactor will continue heating the liquid in the chamber 14. As the liquid in the chamber 14 gets hot, it will set up convection currents so that the heated coolant liquid will pass out through the outlet tube 21, and the cool liquid will come in through the check valve 18 and the intake tube 17.

The device is simple to operate, and easily constructed. The electric fuel pump can be replaced with any desired type of pump, or with gravity feed if necessary. A thermally actuated fuel pump can be used. The use of a thermostat or sensor for the operation of the fuel pump (or valve for fuel), however, is important because it prevents introduction of fuel to the reactor until the reactor is hot enough to support the flameless heat producing reactor. Also, if the reactor quits operating because of a malfunction, the thermostat will cool and the fuel pump will be safely shut off, even if the main switch 53 remains on.

In the use of LP. gas as a fuel, the pump 55 would be replaced by a solenoid valve turned on by the thermostat. The orifice would control fuel flow. The evaporator tube would no longer be necessary.

If desired, a filter or screen can be added to filter the gasoline to prevent plugging of the'orifice.

The heater may be used for air cooled engines by directing the heated air across the engine cylinders.

I claim:

I. A catalytic heater for use for preheating liquid coolant from internal combustion engines comprising ajackct member, said jacket member being liquid tight, means to permit liquid to be transferred into and out of said jacket member, a catalytic reactor element adjacent said jacket member, fuel supply means, evaporator means adjacent said catalytic element, said fuel passing through said evaporator means to vaporized fuel outlet means, said outlet means being positioned so that vaporized fuel and air flows from said fuel outlet means toward said catalytic element, said evaporator means comprising a tube through which said fuel passes embedded in said catalytic element.

2. A flameless heater for use for preheating an internal combustion engine comprising a housing for mounting the heater in an engine compartment, means to mount an elongate tubular catalytic reactor element with its longitudinal axis extending generally vertically in said housing, fuel supply means providing a pressurized combustible fuel without using a fuel pump of the internal combustion engine on which the heater is used, an electrical preheater adjacent said catalytic element for flamelessly preheating at least a portion of said catalytic element to a temperature sufficient for a flameless heat reaction with a vaporized combustible fuel, temperature responsive control means adjacent said catalytic element for operating said fuel supply means. a vaporized fuel outlet receiving combustible fuel under pressure from said fuel supply means, said vaporized fuel outlet positioned adjacent said catalytic element to discharge vaporized fuel into the interior of said tubular catalytic reactor element such that vaporized fuel from said outlet will pass through said catalytic element when said catalytic element is heated and the fuel supply means is operated, said electrical preheater flamelessly heating at least portions of said catalytic element sufficiently to actuate said temperature responsive control means to operate said fuel supply means after said portions reach a temperature sufficient so that a flameless catalytic heat reaction occurs between said element and vaporized fuel supplied by said fuel supply means and an elongate heat exchange engine coolant jacket encircling and extending generally axially adjacent said catalytic reactor element to utilize the flameless heat produced by said heater to warm said internal combustion engine, said internal combustion engine being mounted in a vehicle having a battery, said battery powering said electrical resistance preheater and said fuel supply means, and timer means limiting the length of time said electrical resistance heater is powered, said temperature responsive control means closing an electrical circuit to said fuel supply means independently of said timer means.

l= =l= -l

Claims

1. A catalytic heater for use for preheating liquid coolant from internal combustion engines comprising a jacket member, said jacket member being liquid tight, means to permit liquid to be transferred into and out of said jacket member, a catalytic reactor element adjacent said jacket member, fuel supply means, evaporator means adjacent said catalytic element, said fuel passing through said evaporator means to vaporized fuel outlet means, said outlet means being positioned so that vaporized fuel and air flows from said fuel outlet means toward said catalytic element, said evaporator means comprising a tube through which said fuel passes embedded in said catalytic element.

2. A flameless heater for use for preheating an internal combustion engine comprising a housing for mounting the heater in an engine compartment, means to mount an elongate tubular catalytic reactor element with its longitudinal axis extending generally vertically in said housing, fuel supply means providing a pressurized combustible fuel without using a fuel pump of the internal combustion engine on which the heater is used, an electrical preheater adjacent said catalytic element for flamelessly preheating at least a portion of said catalytic element to a temperature sufficient for a flameless heat reaction with a vaporized combustible fuel, temperature responsive control means adjacent said catalytic element for operating said fuel supply means, a vaporized fuel outlet receiving combustible fuel under pressure from said fuel supply means, said vaporized fuel outlet positioned adjacent said catalytic element to discharge vaporized fuel into the interior of said tubular catalytic reactor element such that vaporized fuel from said outlet will pass through said catalytic element when said catalytic element is heated and the fuel supply means is operated, said electrical preheater flamelessly heating at least portions of said catalytic element sufficiently to actuate said temperature responsive control means to operate said fuel supply means after said portions reach a temperature sufficient so that a flameless catalytic heat reaction occurs between said element and vaporized fuel supplied by said fuel supply means and an elongate heat exchange engine coolant jacket encircling and extending generally axially adjacent said catalytic reactor element to utilize the flameless heat produced by said heater to warm said internal combustion engine, said internal combustion engine being mounted in a vehicle having a battery, said battery powering said electrical resistance preheater and said fuel supply means, and timer means limiting the length of time said electrical resistance heater is powered, said temperature responsive control means closing an electrical circuit to said fuel supply means independently of said timer means.