Apparatus for liquid supply in internal combustion engine

An apparatus for liquid supply in an internal combustion engine having a liquid chamber containing a liquid such as fuel, lubrication oil or the like and located at one side of an intake passage of the internal combustion engine, which liquid chamber is in communication with the intake passage through a delivery passage having a metering throttle interposed therein; and a heating means provided proximately to the throttle portion of the delivery passage.

BACKGROUND OF THE INVENTION 
This invention relates to an apparatus for supplying liquid such as liquid 
fuel such as gasoline, alcohol or the like, or lubrication oil, etc. to 
the interior of an intake passage of an internal combustion engine. 
There has been known apparatus of this kind in which a liquid chamber 
containing liquid such as gasoline or the like is provided at the side of 
an intake passage in an internal combustion engine, and the chamber is in 
communication with the intake passage through a delivery passage having a 
metering or throttle portion interposed therein, so that when there is 
generated a negative pressure in the intake passage, the liquid is sucked 
by the negative pressure into the intake passage through the delivery 
passage. It is usual with this type that the flow rate of the liquid 
introduced thereto will depend on the throttle size of the throttle 
portion, the difference between the pressures of the front side and the 
rear side thereof, and the viscosity of the liquid. Therefore, if the 
viscosity of the liquid is increased with lowering of a temperature, the 
flowing rate thereof tends to be decreased accordingly, but this is not 
desirable. Namely, in the case where the liquid is such fuel as gasoline, 
alcohol or the like, for instance, the starting characteristic of the 
engine, the driving property of the vehicle, the fuel consuming cost and 
others at the time of low temperature are liable to be unfavorable, and in 
the case where the liquid is lubrication oil, for instance, this may cause 
such an inconvenience that oil distribution becomes bad and the friction 
loss is increased. 
SUMMARY OF THE INVENTION 
This invention has for its object the provision of an apparatus free from 
the inconveniences of the prior art. More particularly, an apparatus 
having a liquid chamber containing liquid such as liquid fuel or 
lubrication oil is provided by the side of an intake passage in an 
internal combustion engine, and the liquid chamber is in communication 
with the intake passage through a delivery passage having a metering 
throttle portion interposed therein. This is characterized in that the 
delivery passage is provided at the throttle portion or at the upstream 
side thereof including heating means provided proximately to the throttle 
portion of said delivery passage.

DETAILED DESCRIPTION OF THE INVENTION 
Embodying examples of this invention will now be set forth with reference 
to the accompanying drawings: 
Referring to FIG. 1, illustrating one embodiment of this invention, element 
1 denotes a liquid chamber containing liquid such as liquid fuel, 
lubrication oil or the like and the liquid chamber 1 is in communication 
through a delivery passage 3 having a metering throttle portion 2 
interposed therein, with an intake passage in an internal combustion 
engine (not illustrated), so that a negative pressure is generated in the 
intake passage, the liquid in the liquid chamber 1 may be drawn by the 
negative pressure introduced into the intake passage through the delivery 
passage 3. In other words, the whole of the elements 1, 2 and 3 may serve 
as a carburetor for a fuel supply in an internal combustion engine or an 
apparatus for supply of lubrication oil in a two-cycle internal combustion 
engine. 
The above is not especially different from a conventional engine. According 
to this invention, the delivery passage 3 is provided at the throttle 
portion 2 or on the upstream side thereof with a heater such as an 
electric one or the like for heating so that when the liquid is being 
supplied through the delivery passage 3 the same may be heated by the 
heater 4 and be lowered in its viscosity. 
This will be explained more in detail with reference to the illustrated 
example, as follows: 
The delivery passage 3 is constructed of a metal pipe of which the 
thickness is comparatively large, and an inner annular surface 3a thereof 
is provided with a heat insulation material such as ceramic or the like; 
an outer annular surface 3b thereof is formed with a thermal conduction 
cut-off groove 3e which is applied with a heat insulation material 3d. The 
throttle or restricted portion 2 is of a metering jet type, one as is used 
in a conventional carburetor; the heater 4 is formed by printing or the 
like as a coil-shaped electric type, one of tungsten or the like on the 
inner annular surface or in the interior of the throttle portion as 
illustrated. The heater 4 may for instance, be composed of a 
semi-conductor heater or a temperature controlled type, one combined with 
a DN junction diode having a Pertier effect. 
The heater 4 is constructed to be an electric type one, for instance, as 
illustrated, and is connected to an electric power source 5 such as a 
battery or the like mounted on a vehicle, and there is interposed in a 
connecting circuit a key switch 6 which is arranged to be closed against 
the action of a return spring 6a by insertion of an ignition key or by 
moving thereof to its operative position, and thus the heater 4 can be 
energizing only when the key is inserted or is moved to its operative 
position; thereby, an electric power loss can be eliminated. It is 
preferable in this case that, though not illustrated, the key is so 
arranged that the same is returned automatically to its inoperative 
position, or its pulled-out position, on detecting a stop of the engine by 
a sensing mechanism. 
It is additionally preferably that, though not illustrated, a temperature 
detecting means such, as a thermistor or the like, be provided in the 
delivery passage 3 and the electric current flowing through the heater 4 
is so controlled thereby that the temperature of the liquid flowing 
through the passage 3 may be kept always almost constant. Numeral 7 
denotes a control circuit for this purpose. 
Instead of the thermistor or the like, a construction can be considered 
such that the temperature of the liquid is detected from the amount of the 
electric current flowing through the heater 4, so that the heat generating 
amount of the heater 4 is controlled. It is in general that the control 
temperature is 40.degree.-50.degree. C. where the liquid is gasoline or 
lubrication oil and is 60.degree.-70.degree. where the same is alcohol. 
The operation of the apparatus of this example is as follows: 
If the ignition key is inserted or is further turned to its operative 
position, the key switch 6 is closed, so that the heater 4 is connected to 
the electric source 5 and is operated. Thus, the liquid being drawn to 
flow through the delivery passage 3 into the intake passage by the 
negative pressure is heated by the heater 4 at the restricted metering 
portion 2 or the upstream side thereof to reach a predetermined 
temperature, that is, the foregoing 40.degree.-50.degree. C. or 
60.degree.-70.degree. C., for instance. Consequently, the liquid is 
lowered in its viscosity according to rise in temperature, and the flowing 
rate thereof is always kept to be a predetermined value, and thus the 
foregoing inconvenience in the conventional one wherein the flowing rate 
is decreased can be removed. On this occasion, the heating of the liquid 
is carried out only partially, so that large electric power is not 
required, and a conventional battery is sufficient as the power source. 
FIGS. 2 to 6 show another embodiment of this invention, this embodiment 
serving as an apparatus for supply of lubrication oil in a two-cycle 
internal combustion engine. 
Referring to FIGS. 2 to 6, element 8 denotes an intake passage in a 
two-cycle internal combustion engine; the passage 8 is provided with a 
carburetor for supply of fuel; the liquid chamber 1 is composed of an oil 
chamber containing lubrication oil, while the chamber 1 is in 
communication with a carburetor passage 10 in the carburetor 9 through the 
delivery passage 3. The passage 3 is provided with both the restricted 
metering portion 2 and the heater 4 in almost the same manner as in the 
prior embodiment and, in almost the same manner, the restricted metering 
portion 2 is made of ceramics and the electric heater 4 is embedded 
therein. 
In this embodiment the restricted metering portion 2 is provided with a 
needle valve 11 inserted therein and the valve 11 is connected, together 
with a needle valve 12 in the carburetor 9, to a single common 
acceleration wire 14 through a junction 13. It is desirable, though not 
illustrated, that the carburetor 9 is also provided at its main jet 
portion with a heater. The foregoing carburetor passage 10 is provided 
with a venturi portion 10a, and the delivery passage 3 is arranged to open 
in the venturi portion 10a. Numeral 15 denotes a float chamber of the 
carburetor 9, and as shown clearly in FIG. 4, the chamber 15 is provided 
with a float 16 and a float valve 17 so that a fuel supply opening 18 may 
be opened and closed by the valve 17. This is the case with the oil 
chamber 1; as shown in FIG. 5, the chamber 1 is provided with a float 19 
and a float valve 20 so that a lubrication oil supply opening 21 may be 
opened and closed by the valve 20. As shown in FIG. 6, the foregoing 
heater 4 is connected to the electric source 5 through the key switch 6 
and a control circuit which includes a contact 7c of a relay 7b arranged 
to be operated by a temperature detector 7a, and a covered wire 22 for 
connection. 
The operation of the above embodiment is as follows: 
When a negative pressure is generated in the intake passage 8, the fuel in 
the float chamber 15 of the carburetor 9 is drawn thereto and thus the 
supply of fuel is performed. The negative pressure acts also on the oil 
chamber 1 and the oil in the same is drawn thereby, and thus supply of 
lubrication oil is also achieved. At that time also, the lubrication oil 
is heated by the heater 4 and the viscosity thereof becomes substantially 
constant and, thus, an accurate measuring can be carried out. 
Thus, in this example, the fuel and the lubrication oil are both drawn by 
the negative pressure generated in the intake passage 8 so as to be 
supplied, and a predetermined mixture gas can be obtained simply and 
reliably. 
FIGS. 7 to 10 show a further embodiment thereof, wherein the intake passage 
8 is provided therein with a negative pressure generating portion 23 such 
as a subsidiary venturi or the like which is disposed in series with the 
foregoing venturi portion 10a, and the oil chamber 1 is in communication 
through the passage 3 with that portion 23. 
In the embodiment of FIGS. 7 to 10, the oil chamber 1 is constructed 
separate and apart from the carburetor 9. Alternatively, the same may be 
constructed as one integral unit as shown in the embodiment of FIGS. 11 
and 12. 
The negative pressure generating portion 23, that is, the subsidiary 
venturi, is positioned nearer to the engine side than the venturi 10a of 
the carburetor 9. 
The carburetor 9 is also provided at its main jet portion with a heater 24. 
The remainder parts thereof are not different from those in the foregoing 
example. 
The operation of the apparatus of this further embodiment is as follows: 
The carburetor 9 serves to supply fuel through the venturi 10a by the 
action of the negative pressure generated in the intake passage 8 and, at 
that time, the negative pressure in the intake passage 8 acts at the 
subsidiary venturi 23 to draw the oil contained in the oil chamber 1, and 
on this occasion the drawn oil is heated by the heater 4 when passing the 
delivery passage 3 and the viscosity thereof becomes nearly constant and 
an accurate measuring thereof can be obtained and, thus, the air-fuel 
mixture is led to the engine together with lubrication oil of a 
corresponding amount. 
Many modifications and variations of the present invention are possible in 
light of the above teachings. It is, therefore, to be understood that 
within the scope of the appended claims, the invention may be practiced 
otherwise than as particularly described.