US2487924A - Diesel starting igniter - Google Patents

Description

Nov. 15, 1949 M. G.IIFIEDLER DIESEL STARTING IGNITER Filed Feb. 25, 1944 (a v E? v I 2- lznerri Max;

I'M J5 Patented Nov. 15, 1949 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to Diesel engines and more particularly to means for facilitating starting of such engines.

Specifically, the invention relates to a system for starting this type of engine and to apparatus for use therein. Cold starting of solid fuel injection engines is often difllcult and for this reason various attempts have been made to heat the injection area of the engine and thereby promote starting. Among such devices there is found the sci-called igniter consisting of a glowing element which is inserted in the engine and projects into the combustion space. As is well known, the temperature ranges in Diesel engines are extremely high and as a result of these temperatures and explosion forces, such devices rapidly deteriorate and must be replaced. An important object of the present invention is the provision of a device of this general character, which is so constructed and arranged that it is not subject to destruction, is capable of being economically manufactured and is as readily and quickly insertable and replaceable as the ordinary spark plug.

In the use of prior igniters with which I am familiar, the igniter is usualy continued in operation during the operation of the engine thereby resulting in a considerable current consumption and an increased tendency to the destruction of the unit through its self-generated heat. Fur thermore, such devices are often so located that the operation thereof is ineflicient resulting in erratic operation of the engine during starting period when the burning of the charge is dependent upon the igniter.

A further and important object of the present invention is to so locate the igniter element that it is directly subjected to the spray from the nozzle and to so interconnect the igniter starting motor that the igniter is in operation only during starting of the engine.

These and other objects I obtain by the arrangement illustrated in the accompanying drawings wherein for the purpose of illustration I have shown a preferred embodiment of my invention and wherein:

Fig.1 is a sectional view through a fragment of a Diesel engine cylinder showing an igniter and injection nozzle arrangement in accordance with my invention;

cylinder engine in the starting circuit of the engine.

Referring now more particularly to the drawings, numeral [0 generally designates the head end of a Diesel engine cylinder containing the combustion space I I. In accordance with my invention, the seating shoulder I! provided for the nozzle l3 of the engine is modified to the extent that the nozzle is lnsertable only in one rotative position such rotative position being definitely related to the fuel injection openings of the nozzle. In the present instance, the seating flange I5 of the nozzle is shown as provided with a pin it entering a socket I! in the shoulder l2 although obviously any other suitable means may be employed for this purpose.

The cylinder wall is apertured and threaded for the reception of a bushing it, the inner end of this opening being so disposed that it is in the direct path of the spray S from said fuel inlet opening it. The inner or cylinder end of this opening is closed by a plate IQ of good heat conductivity and which may be readily incandesced. This plate may, as shown in Fig. 1 and as is preferred, be directly attached to the inner end of the bushing l8, which, in this case, is so proportioned that the attached plate coincides as nearly as possible with the surface of the cylinder wall when the bushing is fully inserted, or may, as shown in Fig. 2, be brazed directly to the cylinder wall itself. Mounted in the bushing I8 is a heating element 20 preferably consisting of an outer shell of high heat resisting metal 20. having a filling of alkali metal earth such for example as magnesium chloride. At the inner end of this heating element a heating resistance 2i is embedded. in the alkaline earth filling, one end of the resistance being grounded to the tube 20 and thereby through the bushing [8 to the cylinder wall and the opposite end thereof being connected to a suitable terminal 22.

The heating element 20 is connected in the starting system of-the engine as illustrated in Fig. 3, an arrangement being illustrated for a four cylinder engine. A lead 23 from the starting battery B connects the heating elements 2| in parallel; this lead including a heating resistance R. and the usual starting switch SS. A branch 24 of this lead supplies the starting motor M, this branch including a thermal switch TS actuated to close the branch by the heating resistance R.- The heating resistance R. and thermal switch TS are so proportioned that closure of the starting switch SS the circuit to the starting motor is not completed until the heating enemas elements 29 have generated suficient heat to incandesoe the associated plate 6 9 or to so highly heat the same that a spray contacting the same will be ignited. Since the plate is is so disposed that it is in good heat conductivity to the associated walls of the engine cylinder, its destruction by internally generated temperatures of the cylinder is prevented. This plate in turn serves to isolate the heating element from the cylinder temperatures and the heating element is, of course, itselfin good heat transfer relation to the cylinder walls. The igniters accordingly are not subject to destruction as in the ordinary arrangement and are, of course, so disposed that they may be employed with maximum eficiency. With the close of the starting operation when the switch SS is again opened, the igniter be= comes inactive.

Since the specific construction herein illustrated is of course capable of considerable modification without departing from the spirit of the invention, I do not wish to be understood as limiting myself thereto except as hereinafter claimed.

I claim:

1. Igniter means for use in conjunction with a cylinder of a solid fuel injection engine, comprising a readily heatable plate adapted to form a part of the cylinder wall and conforming to the contour of said wall, said plate when heated providing a hot area on said wall against which a spray of the injected fuel may be directed, and an electrical heater adapted to be positioned behind said plate in cooperative relation therewith to heat the plate.

2. Igniter means according to claim 1, wherein said plate and said heater are embodied in an integral unit which is removably insertable in an opening of the cylinder wall.

3. Igniter means according to claim 1, wherein said plate is permanently secured to the cylinder wall and closes an opening in said wall, and said heater is embodied in a unit which is removably insertable in said opening to bring said heater into cooperative relation with said plate.

4. An igniter for use in a solid fuel injection engine and adapted to be inserted in a threaded opening in a cylinder wall of said engine, said device comprising a shell or bushing adapted to be inserted in said opening and having a readily heatable wall at its inner end adapted to form a part of the cylinder wall and conforming to the contour thereof, said shell having threads coacting with the threads of the cylinder opening in a manner such that when said shell is fully seated in the opening, the inner end wall of the shell and the cylinder wall surface are contiguous, whereby the end wall of the shell when heated provides a hot area on the cylinder wall against ed, and an electrical heater within said shell in cooperative relation with said end wall for heating the latter.

5. An igniter for use in starting solid fuel in jection engines and adapted to be inserted in a threaded opening in that portion of the engine wall defining the combustion space thereof, said igniter comprising a, bushing having the inner end thereof closed by a readily incandescable wall, the bushing having threads coacting with the threads of the cylinder opening in a manner such that when said bushing is fully seated in the opening the inner end wall of the bushing and the inner face of the engine wall are substantially coincident, a heat resistant metal tube supported by the bushing with its inner end in close proximity to the inner end wall of the bushing, an alkaline earth filling for said tube, and an electrical heating resistance in the end of said tube adjacent the inner end wall of said bushing.

62' An igniter for use in starting solid fuel in=- jection engines and adapted to be inserted in a threaded opening in that portion of the engine wall defining the combustion space thereof, said igniter comprising a bushing having the inner end thereof closed by a readily incandescable wall, the bushing having threads coacting with the threads of the cylinder opening in a manner such that when said bushing is fully seated in the opening, the inner end wall of the bushing and the inner face of the engine wall are substantially coincident, a heat resistant metal tube mechanically and electrically joined to the bushing, an alkaline earth filling for said tube, and an electrical heating resistance in the end of said tube adjacent the inner end wall of said bushing having one terminal thereof connected to said tube and the other to a source of current in a circuit including the cylinder wall.

MAX G. FIEDLER.

REFERENEES CK'EED The following references are of record in the file of this patent:

UNITED STATES PA "or.

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