CA1126114A

CA1126114A - Fuel preheater

Info

Publication number: CA1126114A
Application number: CA346,923A
Authority: CA
Inventors: Ernest Woods
Original assignee: Individual
Current assignee: WOODS ERNEST
Priority date: 1980-03-04
Filing date: 1980-03-04
Publication date: 1982-06-22

Abstract

"FUEL PREHEATER"
ABSTRACT OF THE DISCLOSURE
A main conduit is engaged serially with a heater hose extending from the coolant system of an engine to the in-car heater and coolant passes freely therethrough. A fur-ther conduit concentrically surrounds the first conduit and the ends of the further conduit axe secured and sealed to the outer wall of the first conduit as by soldering, brazing or the like thus defining a relatively narrow annular passageway or channel between the two conduits. The further conduit is connected on one side to the fuel tank and on the other side to the metering device such as a carburetor float chamber so that all fuel passing to the carburetor, flows through the narrow annular chamber and is preheated by the heated coolant passing through the first conduit when the engine generates enough heat to heat the coolant passing through said first conduit.

Description

"FUEL PREHEATER"
BACKGROUND OF THE INVEN~ION
This invention relates to new and useful improve-ments in heat exchangers, particularly the heat exchangers adapted for use in the preheating of fuel prior -to same reach-ing the carburetor.
In relative cold climates, where ambient temperatures vary considerably between the seasons, it is well known that for any given automobile, the fuel consumption increases as the ambient temperature decreases.
Ideally, means should be provided whereby the fuel consumption is approximately the same regardless of the pre-vailing ambient temperatures.
Attempts have been made in the past to accomplish this, most of which are involved in preheating the charge prior to it entering the cylinders. As an example, General Motors incorporated an early fuel evaporation valve in conjunction with a thermostatic vacuum switch which direc~s heat to the intake manifold to permit fuel vaporization as the eng:ine warms up.
However prewarming of the charge itself has to be monitored and controlled carefully since too much heat:ing of a ~uel/air mixture will cut down on the volumetric efficiency.
In ol,her words the mixture will become less dense and conse-quently less charge can enter the cylinder during a given in-take stroke thereby entailing less power. Furthermore any '`

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antiknock characteristics of the fuel will be decreased per-ceptively and the risk of preignition burning is of course introduced.
SUMMARY OF THE INVENTION
The present invention overcomes these disadvantages inasmuch as the device warms the fuel prior to its entry to carburetor float chamber or other metering device so that the charge as a whole is not heated unduly.
Heating the fuel rather than the charge el.iminates any danger of fuel boiling and creating vapor lock condi-tions and eliminates any danger of the charge mixture becom-~: ing so lean as to not support combustion.
Preheating the fuel decreases the viscosity there-of thereby assisting in producing better atomization for complete combustion and this preheating of the fuel rather than the charge reduces the dependency of the ambient tem~
perature.
In accordance with the invention there is provid-ed a liquid fuel preheating device for use with automotive engines and the like having a liquid coolant system, in-cluding a selectively controllable circuit operatively con-nected between the coolant system and an in-car heater, a fuel metering dev:Lce ancl a fuel tank operatLvely connected to the meterlng clevlce; comprlslng ln comb:Lnation a main con-duit operatively connected to the ln-car heater clrcult of the coolant system whereby coolant se:Lectively :E:Lows there-- . . - . . - :
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through, a further conduit concentrically surrounding said main conduit and having the ends sealably secured to the outer surface of said main conduit, said further conduit be-ing operatively connected by adiacent one end thereof to the fuel tank and by the other end thereof to the metering device whereby fuel flows from the fuel tank and passes through said other conduit to the metering device, said further con-duit and said main conduit defining an annular channel there-between with the cross sectional area of said annular channel being less than the cross sectional area of said ~n con-duit.
Another advantage of the invention is that it is ~ readily attached or detached from existing vehicles with the ; minimum of trouble and with the minimum of skilled labour.
Another advantage of the invention is that once in-stalled, no monitoring or control is necessary and it can of course be installed on the majority of cars using a coolant system.
Yet another advantage of the present invention is to provide a device of the character herewithin described which is simple in construction, economical in manufacture and otherwise well suited to the purpose for whlch it is designed.
Wlth the ~oregoing in view, ancl othe.r advantages as wil.:L become apparent to those skilled I.n the art to whl.ch this invention relates as this speciEication proceeds, the .: :,, . .
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invention is herein described by reference to t~e accompany-ing drawings Eorming a part hereof, which includes a descrip-tion of the preferred typical embodiments of the principles of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure 1 is a longitudinal cross sectional view of the device per se.
Figure 2 is a cross sectional view along the line - - - . . .. , ~ .,. ~ .. ..

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2-2 of Figure l.
Figure 3 is a schematic view showing the connections of the device to an engine block.
In the drawings like characters of reference indicate corresponding parts in the different figures.

Proceeding therefore to describe the invention in de-tail, reference should first be made to Figures l and 2 inan which a main conduit l0 is provided, with/annular rib l0A form-ed on the outer surface adjacent each end thereof to facilitate the engagement thereon of a coolant hose shown schematically by reference character l0B in Figure 3.
~ The conduit or tube l0 is serially engaged within the coolant hose l0B so that coolant flows in the direction of arrow ll. A further conduit or tube 12 concentrically surrounds the main conduit l0 and the ends 12A are swaged down, in this embodiment, and are secured to the outer surEace of the main conduit l0 by means of solder or braising as indicated by re-ference character 13. Alternatively, the ends may be sealably secured to the conduit l0 by an~ other conventional means.
The concentric relationship of the further tube 12 relative to the main conduit l0, defines an annular chamber 14 between the two conduits and it is de~irab:Le that this chamber be relatively narrow in cross section, the purpose oP which will hereina:Eter be described. In the attached claims, the cross sect:ional area Oe the annular chamber is stated to be .
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less than the cross sectional area of the main conduit 10.
A fuel intake tube 15 communicates with the interior of the further conduit 12 adjacent one end thereof and a fuel outlet tube 16 also communicates with the interior of the fur-ther conduit 12 ad}acent the other end thereof and it is de-sirable -~hat both of these tubes be on the same side of the further conduit 12 as clearly shown in Figures 1 and 2.
The outer ends of the tubes 15 and 16 are preferably flared as illustrated to allow attachment thereto of conduits, other one of which leads from the fuel tank to the tube 15 and the/
which leads from the tube 16 to a metering device such as a carburetor 17. Reference characters 18 and 19, in Figure 3 indicate these two tubes.
In operation, the main conduit 10 is serially engag~
ed between the flexible heater conduit lOB extending from the engine block and through which heated coolant flows to the in-car heater 20.
Fuel from tank 21 is pumped via the conventional pump (not illustrated) to the inlet tube 15 and thence through the annular space 14 between the conduits 10 and 12, to exit via tube 16 and pass to the float chamber of the carburetor 17.
When the car has warmed sufficiently, the coolant ~lowing khrough the main conduit 10 heats the E1lel pa~sing through the chamber 14 pri.or to the fuel entering the carbure-tor Eloat chamber a.nd in this regard the relatively small cross sectional area o~ the annular chamber 14 assists in the rapid " ~, . . . . ~ . : .

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heating of the fuel as it passes therethrough.
By the use of this device, the effect of the ambient temperature is reduced as the temperature of the fuel is main-tained within a reasonably narrow range regardless of whether the ambient temperature is relatively low as in the winter months or relatively high as in the summer months, i~ being understood that in the warmer weather, the in-car heater 20 would not be in use so that coolant would not be flowing through conduit 10.
Tests carried out have shown that an average fuel saving with the device installed is in the order of 8% based on the fuel consumption without the device and as the device is relatively simple in construction and installation, reason-able savings have been effected.
Although the drawings illustrate the device in use with a carburetor using gasoline, lt will be appreciated that any liquid fuel can be used including gasohol, diesel fuel with injection nozzles and the like.
By preheating #2 diesel in the winter months, there 20 are some very definite advantages:
1. ~2 is cheaper 2. ~2 has more energy per gallon

3. 1~2 ha,s better lubrication quality for the injec-tor pumps (less down tirne)

4. Warm ~uel prevents the formation of wax crystals in 1~2 diesel clur:lng cold weather.

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5. By using #2 the threatened shortage of ~1 fuel in the winter months is reduced.
This preheater can be used an air cooled engine by circulating oil in place of coolant through the heater and arrive at the same results.
Since various modifications can be made in my inven-tion as hereinabove described~ and many apparently widely dif-ferent embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the accompanying speci-fication shall be interpreted as illustrative only and not in a limiting sense.

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Claims

WHAT I CLAIM AS MY INVENTION:
(1) A liquid fuel preheating device for use with automotive engines and the like having a liquid coolant sys-tem, including a selectively controllable circuit operative-ly connected between the coolant system and an in-car heater, a fuel metering device and a fuel tank operatively connect-ed to the metering device; comprising in combination a main conduit operatively connected to the in-car heater circuit of the coolant system whereby coolant selectively flows there-through, a further conduit concentrically surrounding said main conduit and having the ends sealably secured to the outer surface of said main conduit, said further conduit being operatively connected by adjacent one end thereof to the fuel tank and by the other end thereof to the metering device whereby fuel flows from the fuel tank and passes through said other conduit to the metering device, said further con-duit and said main conduit defining an annular channel there-between with the cross sectional area of said annular channel being less than the cross sectional area of saicl main conduit.
(2) The device according to Claim 1 in which the ends of said further conduit are swaged down to engage the outer wall of said main conduit and means sealably securing said ends to said outer wall.
(3) The device according to Claims 1 or 2 in which the operative connection from the fuel tank and to the metering device are both on the same side of said further conduit.