JP3707629B2 - Intake air heating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for heating intake air at the time of cold start in an internal combustion engine.
[0002]
[Prior art]
When the internal combustion engine is started at a low temperature, the fuel supplied to the internal combustion engine is poorly vaporized, and the fuel is supplied to the combustion chamber of the internal combustion engine body in a state where the fuel is not sufficiently atomized. There is an example in which a starter-specific bi-starter mechanism is incorporated in the carburetor so as to supply dark fuel at the time of start-up so that the start can be easily performed.
[0003]
However, the dark fuel supplied to the internal combustion engine at the time of start-up is still in a state of poor vaporization, combustion is unstable, start-up time becomes long, and carbon monoxide and hydrocarbons in the exhaust gas It increases or drivability after cold start deteriorates.
[0004]
In view of this, a heater for heating the intake air is conventionally provided in the intake passage of the internal combustion engine. In the example disclosed in Japanese Patent Laid-Open No. 6-257523, a PTC heating element (a positive temperature coefficient thermistor is provided on the inner surface of the intake hole of the internal combustion engine. Element) is attached.
[0005]
When the internal combustion engine is started, the PTC heating element generates heat by energization from the battery, heats the intake air to improve the vaporization of the fuel, improves the warming performance such as smoothing the start and reducing harmful components in the exhaust. are doing. When the temperature of the PTC heating element itself rises to some extent, the resistance becomes infinite and the energization is cut off, heating of the intake air is terminated, and a normal operation state can be entered.
[0006]
[Problems to be solved by the invention]
However, the PTC heating element is a dedicated element for heating the intake air, and a dedicated heating control device for controlling the operation of the PTC heating element must be provided separately, which increases the number of parts and costs. In addition, the PTC heating element is built in the inner surface of the inlet of the intake hole, so that the manufacturing cost of the intake pipe itself increases.
[0007]
The present invention has been made in view of such a point, and the intended process is to use a bi-starter mechanism, which does not require a separate heating control device dedicated to intake air heating, and is excellent in cost reduction. The present invention is to provide an intake air heating device for an internal combustion engine that can ensure a good warm-up performance.
[0008]
[Means for solving the problems and effects]
In order to achieve the above object, the invention of claim 1 includes a carburetor, an electric bi-starter mechanism provided in the carburetor for adjusting the mixture when the internal combustion engine is warmed up, a carburetor, and the internal combustion engine body. In the internal combustion engine including the intake pipe to be connected, the control circuit of the electric bi-starter mechanism is a control circuit using a positive temperature coefficient thermistor element, a resistance heating element is connected in series to the positive temperature coefficient thermistor element, and the resistance heat generation The body is an intake air heating apparatus for an internal combustion engine that is fixed to the outer wall of the intake pipe by a bolt with flat surfaces in contact with each other .
[0009]
The electric heating starter mechanism is used and a resistance heating element that heats the intake pipe is connected to the control circuit. Therefore, a separate circuit for controlling the operation of the resistance heating element is not required. It is possible to heat the intake air for the time.
Therefore, the cost can be greatly reduced, and the startability can be smoothly performed to maintain the warm-up performance well, the harmful components in the exhaust gas can be reduced, and the drivability after the low temperature start can be improved.
[0010]
By connecting the resistance heating element in series to the positive temperature coefficient thermistor element, the resistance that has been conventionally installed in the control circuit of the electric bi-starter mechanism is used for heating the intake air as a heating resistor. A heating element dedicated to intake air heating is not required and the cost is low, and the warm-up performance can be kept good in conjunction with the operation of the bi-starter mechanism.
[0011]
The resistance heating element is fixed to the outer wall of the intake pipe, the structure is simplified and the assembly work is easy, and the characteristic of the control circuit of the bi-starter mechanism can be easily changed by replacing the resistance heating element. Since it can be configured with simple resistance, durability, reliability, and serviceability are greatly improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is a side view of a scooter type motorcycle 1 provided with a unit swing type internal combustion engine according to the present embodiment.
[0013]
The vehicle body front part 2 and the vehicle body rear part 3 are connected via a low floor part 4, and the vehicle body frame 5 that forms the skeleton of the vehicle body branches into two after descending the vehicle body front part and below the floor part 4. The vehicle body rear part 3 is then extended upward and rearward.
[0014]
A seat 6 is provided at the upper part of the rear part 3 of the vehicle body, and a steering head 8 having a handle 7 is provided at the upper part of the front part 2 of the front vehicle body. A front wheel 10 is suspended from the front body 2 via a front fork 9 and is steered by a handle 7.
[0015]
Then, a bracket 11 is projected from a cross member erected between the left and right inclined portions rising obliquely above the rear portion of the body frame 5 (see FIG. 10), and the unit swing case 16 is mounted on the pivot 12 supported by the bracket 11. A pair of left and right hanger brackets 17 projecting upward from the front are pivotally supported so that the swing unit 15 can swing up and down, and a rear cushion 19 is interposed between the body frame 5 and the rear of the pivot 12. It is disguised.
[0016]
An internal combustion engine 20 is integrally provided at the front part of the swing unit 15, and a rear wheel 21 is pivotally supported at the rear part. Power of the internal combustion engine 20 is transmitted to the rear wheel 21 by a belt transmission mechanism 22 having an automatic transmission function. Is done. The fuel tank 23 is fixedly mounted on the vehicle body frame 5 below the floor portion 4.
[0017]
The internal combustion engine 20 is a two-cycle internal combustion engine, and a cylinder 25 protrudes slightly upward from the front part of the unit swing case 16, and the cylinder 25 is located below the pivot 12 and between the left and right body frames 5. It penetrates.
[0018]
The internal combustion engine 20 employs a crankcase reed valve system in which a reed valve is provided in the crankcase portion, and an intake pipe 27 extends from the upper portion of the crankcase portion of the unit swing case 16 as shown in FIG. The rear wheel 21 avoids the rear wheel 21 and extends rearward on the left side and is connected to the carburetor 28. Air is introduced into the carburetor 28 from an air cleaner 29 mounted on the rear part of the unit swing case 16.
[0019]
An exhaust pipe 30 extending downward from the lower portion of the cylinder 25 of the internal combustion engine 20 is connected to a muffler 31 disposed on the right side of the vehicle body, bypassing the lower side of the crankcase portion 16a backward and to the right. An AC generator 32 is provided at the right end of the crankshaft of the engine 20.
[0020]
The carburetor 28 is an electric motorcycle starter provided with an air passage 41 for a starter separately from an original venturi air passage between an intake air inlet 28a and an air-fuel mixture outlet 28b connected to an air cleaner 29. It has a structure in which the mechanism 40 is integrated.
[0021]
FIG. 3 is a cross-sectional view of the motorcycle starter mechanism 40. A cylindrical valve 43 is slidably fitted up and down between an intake air introduction path 41a and an air-fuel mixture outlet path 41b. In the valve 43, a bi-starter needle 44 is inserted so as to be slidable inside perpendicularly to an air passage 43a formed in a side wall, and the bi-starter needle 44 penetrates the tip downward and communicates from below with a fuel supply passage 45. Is inserted into the opening.
[0022]
Above the valve 43, a sleeve 46 is urged upward by a spring 47 so as to freely move up and down, and a locking projection 46a protruding downward from the lower portion of the sleeve 46 inserts the tip into the valve 43. ing. The sleeve 46 is integrally fitted with a piston 47 that slides up and down by a thermo wax 48 disposed above the sleeve 46, and the thermo wax 48 is a PTC heater 49 that is a positive temperature coefficient thermistor element provided on the top. Is heated by. A cord 50 that is a power line is connected to the PTC heater 49.
[0023]
The motorcycle starter mechanism 40 has the above-described structure. When the temperature is not heated by the PTC heater 49, the valve 43 is open. When the PTC heater 49 is energized to generate heat and the thermowax 48 is heated, The thermowax 48 expands and pushes down the piston 47 against the spring 47 together with the sleeve 46. When the thermowax 48 is lowered a predetermined distance, the locking projection 46a of the sleeve 46 hits the head of the bi-starter needle 44, and the bi-starter needle 44 together with the valve 43 The valve is pushed down to decrease the fuel supply. Finally, the fuel supply is stopped and the valve 43 is closed at the same time.
[0024]
The PTC heater 49 generates heat when energized, and has a property that the resistance becomes infinite when a certain temperature is exceeded. Therefore, the energization is automatically stopped when a predetermined temperature is exceeded. When the energization is stopped, the internal combustion engine is out of the cold state, the motorcycle starter mechanism 40 keeps the valve 43 closed, and the carburetor 28 does not depend on the motorcycle starter mechanism 40.
[0025]
As described above, the motorcycle starter mechanism 40 opens the valve 43 at the time of low temperature start of the internal combustion engine to supply fuel, so that the start is easily performed with the fuel supplied to the internal combustion engine being dark, and the cold engine state When the engine is released, the valve 43 is automatically closed and the fuel supply by the motorcycle starter mechanism 40 is stopped.
[0026]
The intake pipe 27 connected to the gas mixture outlet 28b of the carburetor 28 incorporating such a motorcycle starter mechanism 40 extends upward from the upper part of the crankcase portion as described above, and then bends substantially to the left rear. Since the gas is liable to be liquefied and collected in a structure that is inherently difficult to warm because it extends relatively long horizontally and is connected to the vaporizer 28, the resistance heating element 60 is bolted from the outside to the intake pipe 27 in this embodiment. The structure is fixed by 65 (see FIG. 2).
[0027]
As shown in FIG. 4, an inverted T-shaped flat surface 27a is formed on the rear side surface of the intake pipe 27, and a mounting hole 27b for a bolt 65 is provided in a part thereof. On the other hand, as shown in FIGS. 6 to 9, the resistance heating element 60 is inverted T-shaped in a front view from a rectangular box portion 61a elongated in the left and right direction and a bracket portion 61b whose center bulges along the opening surface. A steel case 61 is formed, and a nichrome wire 63 is embedded in a heat-resistant cement 62 filled in the rectangular box portion 61a.
[0028]
One end of the nichrome wire 63 is fixed to the case 61, and the other end is connected to the cord 64 and extends outward from the bottom wall of the rectangular box portion 61a of the case 61.
A bolt hole 61c is formed in the bracket portion 61b, and the heat resistant cement 62 in which the nichrome wire 63 is embedded forms a flat surface in the opening of the rectangular box portion 61a.
[0029]
The resistance heating element 60 is brought into contact with the flat surface 27a of the intake pipe 27 in contact with the inverted T-shaped flat surface 27a, the bolt hole 61c is aligned with the mounting hole 27b, and the bolt 65 is screwed. (See FIG. 5). Therefore, when the nichrome wire 63 is energized, it generates heat and the intake pipe 27 is heated via the heat-resistant cement 62.
[0030]
As shown in FIG. 10, a cord 64 extending from the resistance heating element 60 and a cord 50 extending from the motorcycle starter mechanism 40 extend upward and are connected to a connecting portion 36 of the wire harness 35 positioned at the inclined portion of the left body frame 5. The cord 33 extending from the AC generator 32 is connected to the wire harness 35 via the connector 34.
[0031]
A control circuit of the motorcycle starter mechanism 40 and the resistance heating element 60 is shown in FIG. In the AC generator 32, a cord 33 connected to the power generation coil is connected to a cord 50a extending from one end of a PTC heater 49 of the motorcycle starter mechanism 40 via a connector 34, a wire harness 35, and a coupling portion 36. The cord 50b connected to the other end is connected to a cord 64 extending from the nichrome wire 63 of the resistance heating element 60 via the coupling portion 36, and the other end of the nichrome wire 63 is in contact with the vehicle body via the case 61. That is, the PTC heater 49 and the nichrome wire 63 are connected in series to the power source of the AC generator 32.
[0032]
As described above, the PTC heater 49 is turned off because the resistance becomes infinite at a certain temperature or higher. At that time, the nichrome wire 63 is not turned on and the resistance heating element 60 stops generating heat.
[0033]
Therefore, the resistance heating element 60 generates heat and heats the intake pipe 27 only when the motorcycle starter mechanism 40 is in a cold state at the time of cold start of the internal combustion engine and dark fuel is supplied. By heating the air-fuel mixture that is in a state in which the gas easily liquefies through the inside of the intake pipe 27, it is possible to maintain good fuel vaporization.
[0034]
Therefore, it is possible to smoothly start the internal combustion engine, improve warm-up performance, reduce harmful components in the exhaust, and improve drivability after low-temperature start.
[0035]
As described above, in the present embodiment, the control circuit of the motorcycle starter mechanism 40 uses the resistance connected in series to the PTC heater 49 as the resistance heating element 60 and the control circuit for the resistance heating element 60 that heats the intake pipe 27. Also use.
Therefore, a heating element and a control circuit dedicated to special intake air heating are unnecessary, the number of parts is small, the structure is simple, and the cost can be greatly reduced.
[0036]
The resistance heating element 60 is an external structure fixed to the outer surface of the intake pipe 27. Therefore, the structure is simplified and the structure is composed of a simple nichrome wire 63, which has durability, reliability, and serviceability. It has improved significantly.
[Brief description of the drawings]
FIG. 1 is a side view of a scooter type motorcycle provided with a unit swing type internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a plan view in which a part of the front portion of the swing unit is omitted.
FIG. 3 is a cross-sectional view of a motorcycle starter mechanism.
FIG. 4 is a rear view of the intake pipe.
FIG. 5 is a rear view of a state in which a resistance heating element is attached to the intake pipe.
FIG. 6 is a front view of a resistance heating element.
FIG. 7 is a top view with the same part cut away.
FIG. 8 is a side view of the same.
FIG. 9 is a back view of the same.
FIG. 10 is a perspective view of a principal part, partially omitted, showing a wiring state of a control circuit.
FIG. 11 is a control circuit diagram of a motorcycle starter mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... Front part of vehicle body, 3 ... Rear part of vehicle body, 4 ... Floor part, 5 ... Body frame, 6 ... Seat, 7 ... Handle, 8 ... Steering head, 9 ... Front fork, 10 ... Front wheel, 11 ... Bracket, 12 ... Axis, 15 ... Swing unit, 16 ... Swing case, 17 ... Hanger bracket, 19 ... Rear cushion,
20 ... Internal combustion engine, 21 ... Rear wheel, 22 ... Belt transmission mechanism, 23 ... Fuel tank, 25 ... Cylinder, 27 ... Intake pipe, 28 ... Vaporizer, 29 ... Air cleaner, 30 ... Exhaust pipe, 31 ... Muffler, 32 ... AC generator, 33 ... cord, 34 ... connector, 35 ... wire harness, 36 ... joint,
40 ... motorcycle starter mechanism, 41 ... air passage, 43 ... valve, 44 ... bi-starter needle, 45 ... fuel supply passage, 46 ... sleeve, 47 ... spring, 48 ... thermowax, 49 ... PTC heater, 50 ... cord,
60 ... resistance heating element, 61 ... case, 62 ... heat-resistant cement, 63 ... nichrome wire, 64 ... cord, 65 ... bolt.

Claims (4)

In an internal combustion engine comprising a carburetor, an electric bi-starter mechanism provided in the carburetor for adjusting an air-fuel mixture when the internal combustion engine is warmed up, and an intake pipe connecting the carburetor and the internal combustion engine body,
The control circuit of the electric bi-starter mechanism is a control circuit using a positive temperature coefficient thermistor element, and a resistance heating element is connected in series to the positive temperature coefficient thermistor element,
The internal combustion engine intake heating apparatus according to claim 1, wherein the resistance heating element is fixed to the outer wall of the intake pipe in a detachable manner by abutting flat surfaces with each other . In an internal combustion engine comprising a carburetor, an electric bi-starter mechanism provided in the carburetor for adjusting an air-fuel mixture when the internal combustion engine is warmed up, and an intake pipe connecting the carburetor and the internal combustion engine body,
The control circuit of the electric bi-starter mechanism is a control circuit using a positive temperature coefficient thermistor element, and the resistance heating element is connected in series to the positive temperature coefficient thermistor element,
The intake heating device for an internal combustion engine, wherein the resistance heating element is fixed to an outer wall of the intake pipe opposite to the main body side of the internal combustion engine . 3. The intake air heating apparatus for an internal combustion engine according to claim 2, wherein the intake pipe is arranged behind the internal combustion engine main body . 4. An intake air heating apparatus for an internal combustion engine according to claim 3, wherein the resistance heating elements are detachably fixed by bolts with their flat surfaces abutting against the outer wall of the intake pipe.

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