April 13, 1965 'r. cuRzON 3,178,149
VALVE DEVICE FOR AIDING' THE STARTING OF INTERNAL COMBUSTION ENGINES Filed June 6, 1962 2 Sheets-Sheet 1 April 13, 1965 Filed June 6, 1962 T CURZON VALVE DEVICE Foh AIDING THE STARTING OF INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 United States Patent VALVE DEVICE FOR AIDING THE STARTING OF INTERNAL COMBUSTION ENGINES Thomas Curzon, London, England, assignor to C.A.V. Limited, London, England Filed June 6, 1962, Ser. No. 200,571
Claims priority, application Great Britain, June 12, 1961,
21,087/ 61 1 Claim. (Cl. 251-11) This invention relates to a device for aiding the starting of internal combustion engines, the device being of the kind adapted to be mounted in the air intake manifold of the engine and comprising a tubular body having a liquid fuel inlet at one end, an electrically heatable coil surrounding the body, a valve seating in the body, and a stern mounted within the body and adapted to hold a valve closure member against the seating, the stem and body having different thermal coefficients of expansion whereby when the body and stem are heated the closure member can move away from the seating to admit of flow of fuel through the body.
In such devices it is intended that the liquid fuel be vapourised as it passes through the heated body. However, it has been found that there is a tendency for the liquid fuel to How along the stem due to surface adhesion, thereby resulting in insufficient vapourisation of the fuel. Also the liquid fuel flowing along the stem tends to cool the stem in relation to the body thereby resulting in inconsistent fuel flow.
The object of this invention is to provide a construction of a device of the kind specified whereby the above mentioned disadvantages may be minimised.
According to the invention a device of the kind specified is characterised in that the periphery of the stem is treated to provide a surface which is interrupted in a longitudinal direction.
In the accompanying drawings:
FIGURE 1 is a part sectional side view of one example of the invention and FIGURE 2 is a part sectional side view of a further example of the invention.
Referring to FIGURE 1 of the drawings there is provided a substantially cylindrical outer casing 1 having on its periphery a screw thread 2 whereby it may be engaged with a complementary screw threaded hole in the air intake manifold of the engine (not shown). At one end of the casing is a cylindrical extension 3 having in its periphery holes 4 through which air can enter the extension from the manifold. Within the casing and its extension is co-axially mounted a tubular body part 5. The end 6 of the body extends from the casing and is externally screw threaded or otherwise adapted for connection to a fuel pipe (not shown) through which liquid fuel can be fed to a stepped bore in the body. Surrounding the opposite end of the body is an electric heating element, which is formed out of a continuous piece of Wire, but which is coiled to stepped form. The smaller diameter portion 7a surrounds the body part in close proximity thereto, whilst the portion having the larger diameter extends within the extension 3. The heating element is electrically insulated from the body and has one end secured to the extension and the other end connected to the terminal 8 mounted at the outer end of the casing.
The end of the bore 10 adjacent the extension 3 is formed with a screw thread on its periphery and is engaged by a complementary screw threaded plug 15 which is provided with a stem 13 which extends with clearance towards the outer end of the body. Moreover mounted on this end of the stem is a ball 12 which can co-operate with a seating 11 formed by an annular shoulder in the bore. Furthermore the stem 13 is formed from material having a smaller temperature coefficient of expansion than the material of the body 5, and formed in the plug is an outlet slot 16 through which vapourised fuel can flow.
The arrangement is such that, when it is required to start the engine with which the device is associated, the heating element is connected to a source of electric supply and portion 7a of the element heats the adjacent portion of the body causing it to expand and allowing the ball 12 to be moved from the seating 11 thereby allowing fuel to flow into the bore 10. The stem 13 is formed with a helical thread on its periphery so as to provide a surface which is interrupted in a longitudinal direction, and this restrains the fuel in its passage to the outlet slot 16. During the time the fuel is within the bore it is vapourised and when it emerges from the outlet slot it mixes with air flowing through the manifold and the portion 712 of the element ignites the vapour and air mixture. The effect of this is to heat the air being drawn into the engine and this assists the starting of the engine.
As soon as the engine starts the heating element is disconnected from the source of supply and the body cools thereby allowing the ball to again act with the seating to prevent the flow of fuel. In a further example of the invention as shown in FIGURE 2 the extension is omitted and the heating element is in the form of strip material which is helically coiled so that there is formed a portion 14a having a smaller diameter and serving to heat the body and a portion 14b of larger diameter which surrounds a portion of the body and extends from beyond the end thereof. Moreover in this case the end of the element remote from the terminal is connected to the body. In this example the screw thread upon the internal periphery of the bore, and which supports the plug, is extended to the end of the bore and serves to prevent fuel running straight down the wall of the bore to the outlet slot. Furthermore instead of forming a screw thread on the stem the periphery of the stem is knurled to produce a surface which is interrupted in a longitudinal direction, or alternatively the surface may be sand-blasted to roughen it.
By the invention the surface treatment of the stem serves to minimise the risk of liquid fuel running along the stem and, as in the second example, along the internal periphery of the body, and thereby improves vapourisation of the fuel.
Having thus described my invention what I claim as new and desire to secure by Letters Patent is:
A device for aiding the starting of an internal combustion engine and of the kind intended to be mounted in the air inlet manifold of the engine comprising, a body in which is formed a bore, a liquid fuel inlet at one end of the bore, a seating defined within the bore, a plug 32 mounted within the end of the bore remote from the inlet, a stern of smaller diameter than the bore mounted on the plug and extending towards the inlet, said stem being formed of material having a smaller temperature coefficient of expansion than the material of which the body is formed and having its peripheral surface interrupted in a longitudinal direction, a passage defined between the plug and the body, a valve closure member mounted on the stern for co-operation with the seating, and an electrical heating element surrounding the body and arranged when energised to heat the body to cause the latter to expand thereby allowing the closure member to be urged otf the seating and allowing fuel to flow from the inlet and through the passage defined between the plug and the body.
References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS Austria. Great Britain.
M. CARY NELSON, Primary Examiner. 15 MILTON KAUFMAN, Examiner.