US2192688A - Reigniter for automobile heaters - Google Patents

Description

March 5 1940 H. J. DE N. MccoLLuM 2,192,688

REIGNITER FOR AUTOMOBILE HEATERS Filed Nov. 29. 1937 Patented Mar. 5, 194() PATENT OFFICE REIGNITER FOR AUTOMOBILE HEATERS l Henryl De N. McCollum, Evanston, lll. Application November 29, 1937, Serial No. 177,078

2 Claims.

My invention relates generally to automobile heaters of the internal combustion type and more particularly to refigniters for use in heaters of this type.

A In heaters of the general type disclosed in my co-pending application Serial No. 61,213, iiled January 28, 1936, difllculty was occasionally experienced in the operation of the heater due to the fact that the reigniter plug therein failed tofunction under certain conditions of operation. For example, the heater might be started in the usual manner and operate a sufllcient length of time to cause the thermostatically controlled switch to disconnect the electrical igniter from the source of current prior to the time that the reigniter plug had been raised to a sumcient temperature to cause reignltion of the combustible mixture in the combustion chamber. This might occur if the flame in the combustion chamber became extinguished due to an unusual and s sudden decrease in the intakemaniiold vacuum. l

Under such circumstances, the ame might remain extinguished for a short period until the heater became cooled sufficiently again to cause the thermostatically controlled switch to close the circuit to the electrical igniter. Such Aoperation had the disadvantage that the heater was temporarily ineffective to heat the passenger compartment oi the vehicle and also because of the additional undesirable drain upon the automobile battery due to the second operation of the electrical igniter.

It is therefore an object oi my present invention to provide an improved reigniter plug which is effective to maintain combustion in the combustion chamber after being heated for a relatively short interval of time.

A further object is to provide an improved reigniter for heaters o! the internal combustion type in which the shape of the reigniter is such that it is rapidly raised to its effective ignition temperature.

Other objects will appear from the following description, reference being had to the accompanying drawing, in which:

Fig. l is a fragmentary sectional View of an automobile heater incorporating the improved reigniter plug of the present invention; and

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. l, showing the reigniter plug in elevation. Y

In order that the improved operating characteristics of the reigniter plug may be more readily understood, the description thereof will be preceded by a brief general 'description of the heater in which it is incorporated.

The heater comprises generally a casting Ill having a combustion chamber I2 formed therein and to which a combustible mixture of liquid fuel (gasoline) and air is supplied through a tube I4 from a carbureting device I6, the latter being supplied with liquid fuel through a conduit I8 which is connected to receive fuel from the fuel supply system of the automobile in which the heater is installed, herein shown as connected to the oat bowl 20 of the engine carburetor.

Ihe combustible mixture of air and fuel supplied to the combustion chamber I2 is raised to its kindling temperature by an electrical igniter 22 which is generally in the form of a high resistance nichrome wire. The products of combustion flow past the reigniter plug 24, hereinafter to be described in detail, and thence through circuitous passageways formed in a radiator core 26 which is surrounded by a shell 21 and heat radiating iln s 28. A Venturi type nozzle 30 is positioned at the end of the circuitous passageway formed in the radiator core 26,V and is con- A nected by a passageway 32 with a conduit 34 leading to the intake manifold 36 of the engine of the automobile upon which the heater is mounted.

The operation of the heater is controlled by means of a knob 38 secured to a rod 40, which, at its end, has a valve 42 engageable with the mouth of the Venturi type nozzle 30 to cut oi ow of gases through the heater. The control knob 28 also serves as a means for operating ar pairof switches 44, 46, which respectively control4 the flow of current to a motor 48 which drives a fan 50. and control the flow of current to the electrical igniter 22. The operation of this switch is such that when the control knob :z is puued outwarcny to initiate operation 4 of the heater, the switch 46 will close i'lrst and cause the electrical igniter 22 to be supplied with heater current. The electrical igniter having ignited the combustible mixture which is drawn through the carbureting device I6 by the intake 45 manifold suction, the heat of combustion raises the temperature of the-radiator core 26 and its associated shell 21 to' a' high temperature, the heat being also transmitted to a bimetal thermostatic actuator 52, the lower end of which 50 moves to the left as the element becomes heated. In this manner, the contacts of the switch 46 will first be opened as the heater attains its substantially normal operating temperature. Shortly thereafter, with a slight increase in the tem- 55 perature of the thermostatic element 52, the latter will close the contact switch 44, and thus the vfan 50 will beoperated to circulate air from the passenger compartment of the vehicle past the radiator 26, 21, 28.

'I'he reigniter plug 24 is made of a ceramic material having a relatively thick central por-4 tion 54 provided with a cylindrical recess 56 and a plurality of concentrically arranged perfora-.

tions 58 which form passageways for the flow of the products of combustion from the combustion chamber I2 to the passageway in the radiator core. Alternate perforations 58Vare intercepted by slots 60 extending radially inwardly from the edge of the plug. These slots are provided to allow for the expansion and contraction of the plug with changes in temperature.

` Upon initiation of the operation Vof the heater, the hot gases of combustion Will surround and impinge against the surface of the reigniter plug, and rapidly heat the latter. The central portion of the plug is in elect thermally insulated from the walls of the combustion chamber so that this portion of the plug will rapidly be raised to the temperature of incandescence at which it is capable of reigniting the combustible mixture should the flame become extinguished accidentally. The central portion 54 of the plug provides a suiiicient heat retaining mass around the recess 56 so that the walls of said recess will be maintained'at an ignition temperature for a considerable length of time. Thus, under adverse conditions of engine operation, when the intake manifold vacuum uctuatesgreatly, the reignition plug will maintain its ignition temperature during the periods when the intake manifold vacuum is insuicient to maintain the flow of combustible mixture into the combustion chamber at the rate suilcient to maintain proper combustion. The reigniterplug will, during these periods, cause ignition of such o! the combustible mixture as is drawn into the combustion chamber even though th'e rate at which it flows is insuilicient to maintain a steady ame, and unless the period of insuiiicient intake manifold vacuum is excessively extended, the reigniter will cause reignition and resumption of steady operation as soon as the intake manifold vacuum is suflicient to cause flow through the heater at a normal rate.

The reigniter plug 24, due to its improved shape, will heat up so rapidly that it will have attained incandescence or at least a temperature surllcient to ignite thev combustible mixture prior to the time that the thermostatic element 52 opens the electrical igniter control switch 46.`

Thus, during the initial starting period, the combustion will be maintained in the first instance by the electrical igniter, for a short period by' both the electrical igniter and the reigniter plug, and thereafter, solely by the reigniter plug. As

a result, there is but a very slight possibility that the flame in the combustion chamber will become extinguished due to extended erratic variations in the degree of intake manifold vacuum, and the possibility that the electrical igniter will be energized more than once substantially eliminated.

Of course, if the operator of the vehicle permits the engine to remain stopped for an extended period, the reigniter plug may cool suiiiciently to necessitate reenergization of the electrical igniter, but with the improved reigniter disclosed herein, the possibility that the intake manifold suction will be reduced for such an extended period during regular operation of the vehicle is so small as to be negligible.

While I have shown and described a particular form of reigniter, it will be apparent to those skilled in the art that variations and modiiications thereof may be made without departing from the essential features of my invention set forth in the accompanying claims. I therefore desire, by these claims to include as my invention all such -modifications and variations by which substantially the same results are secured in substantially the same way.

I claim:

1. In an automobile heater of the internal combustion type, a combustion chamber, means to supply a combustible mixture to said chamber, electrical means for igniting the mixture in said chamber, means responsive to the temperature of the products of combustion owing from said chamber to deenergize said electrical igniter, and a reigniter forming a wall of said combustion chamber and having a central portion of greater thickness than the edge portion thereof, said central portion projecting into said combustion chamber in the path of flow of the burning gases therethrough and having a relatively deep recess formed therein, said recess opening into said combustion chamber.

2. In a heating apparatus in which a combustible mixture of fuel and air is supplied to a combustion chamber and the products of combustion are drawn from the combustion chamber through a heat transfer device by a source of suction which may occasionally fail, a reigniter plug adapted for location between the combustion chamber and the heat exchange device to reignite the combustible mixture after a short failure of said source of suction, said plug being of a ceramic material and having a plurality of generally cylindrical passageways extending therethrough', said passageways being spaced a short distance from the periphery of the plug and at least some of said passageways having communieating slots extending to the periphery of the plug, said plug having a central recess formed in one side thereof.

HENRY J. DE N. yMcCOLLUM.

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