JP4683487B2 - Engine with breather device - Google Patents

Description

  The present invention relates to an engine with a breather device, and more particularly to an engine with a breather device suitable for suppressing moisture icing in a breather passage.

  In a small general-purpose engine used for an engine-driven generator or the like, a breather tube is routed outside the engine in order to allow blow-by gas to communicate with an intake passage. Therefore, in this type of engine, the breather tube is exposed to the outside air temperature, and in cold regions where the outside air temperature is extremely low, the moisture contained in the blow-by gas passing through the breather tube freezes to block the breather tube. It can happen.

As a countermeasure, for example, in an engine described in Japanese Patent Application Laid-Open No. 8-151917, the breather tube is guided by introducing cooling exhaust air from a cylinder or a muffler, which is a high temperature portion during engine operation, to the outer peripheral portion of the breather tube. Attempts have been made to heat. Japanese Utility Model Publication No. 61-2253 proposes a blow-by gas introduction device in which a breather tube is heated by an electric heater.
Japanese Patent Laid-Open No. 8-151917 Japanese Utility Model Publication No. 61-2253

  In the apparatus described in Patent Document 1, since cold air is blown when the engine is started, the effect of heating cannot be obtained. Rather, blowing cold air may promote moisture freezing. Further, in the apparatus described in Patent Document 2, the breather tube or the connection portion between the breather tube and the engine is considerably low in temperature, so that a heating effect cannot be obtained unless a large heat capacity heater is used. Even if a heater with a large heat capacity is used, there is a problem that it is not easy to secure the arrangement space.

  The objective of this invention is providing the engine with a breather apparatus suitable for heating the gas which eliminates the said subject and passes the inside of a breather tube efficiently.

  In order to achieve the above object, the present invention provides an engine with a breather device that introduces blowby gas into an intake passage of an engine via a blowby gas passage, wherein a breather tube that is an external passage portion of the engine is included in the blowby gas passage. A breather heater which is composed of a joint tube and a divided tube connected to both ends of the joint tube, and is supported by the inner periphery of a slot formed in the tube wall of the joint tube and protrudes inside the joint tube There is a first feature in that

  In addition, the present invention has a second feature in that the breather heater includes a heater body and a radiator that extends from the heater body in the longitudinal direction of the breather tube and dissipates heat generated by the heater body. .

  In addition, the present invention has a third feature in that the heater body is a PTC heater covered with a case, and the radiator is joined to the case.

  Furthermore, the present invention has a fourth feature in that a cylindrical heat insulator that covers at least the joint tube including the slot among the breather tubes is provided.

  According to the present invention having the first feature, since the gas passing through the breather tube is directly heated by the breather heater, the breather tube can be efficiently heated. Moreover, since the breather heater can be attached to the engine via the divided tube in a state of being integrated with the joint tube in advance, the breather heater can be easily attached. Since the breather heater is supported by the joint tube and protrudes inwardly, it becomes difficult to release heat to the outside air through the breather tube, and the inside of the breather tube can be efficiently heated. In addition, since it is easy to remove the breather heater in engines other than those for cold regions, the engine can be made common to each destination, and can be easily taken out in seasons other than the cold season.

  In the present invention having the second feature, since a large heat radiation area can be secured along the longitudinal direction of the breather tube, the heating effect on the gas flow passing through the breather tube is great. Further, even when the heater main body cannot be disposed directly on the portion to be heated due to the structure, the desired portion can be heated via the radiator.

  In the present invention having the third feature, since the PTC heater performs a self-temperature control action, control for heating is unnecessary, and the configuration is simplified. In addition, the PTC heater is not covered with the breather tube, but is covered with the case and provided inside the breather tube, and directly exposed to the passing flow, so that the amount of wasted heat consumed for heating the breather tube itself is reduced. Efficient heating is possible.

  According to the fourth feature, the amount of heat released to the outside air through the breather tube can be further reduced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a perspective view of an engine-driven generator driven by an engine with a breather device according to an embodiment of the present invention. The generator 1 includes an engine 4 and a generator main body 5 housed in the bottom of a space formed by a bottom plate 2 and a pipe-like frame 3. A fuel tank 6 is provided above the engine 4 and the generator body 5, and an operation panel 7 is disposed behind the fuel tank 6. An air cleaner 8 and a muffler 9 are disposed adjacent to the engine 4. A breather tube 11 is provided between the head cover 10 of the engine 4 and the air cleaner 8 to connect the two. The breather tube 11 passes through a support portion (choke stay) of the choke assembly 12, and one end is inserted into a hole formed in the head cover 10, and the other end is drawn into the case of the air cleaner 8 to hook inside (not shown). ).

  FIG. 4 is an exploded view of the heating part of the breather tube 11, that is, the breather heater. In the figure, a breather heater 13 includes a heater body 14 that is a heating element, a pair of electrode plates 15 and 15 disposed on both sides of the heater body 14, and electrical wirings 17 and 17 connected to the electrode plates 15 and 15. And a case 21. The electric wires 17 and 17 are connected to a power source (not shown). In this embodiment, a PTC heater which is a semiconductor ceramic made of barium titanate is used as the heater body 14. The PTC heater has a characteristic that heat is generated and resistance is increased when a current is passed. As a result, the flowing current decreases and the temperature decreases. When the temperature decreases, the resistance decreases and the flow of current increases. As described above, the PTC heater is advantageous in that it has a self-temperature control function in which the temperature becomes constant without specially providing a control device.

  The case 21 is a substantially rectangular parallelepiped container having one surface opened, and a flange 21A is provided on the edge of the open surface. The case 21 is preferably a deep-drawn molded product made of a metal having good thermal conductivity, such as copper, brass, or aluminum. The side surfaces of the case 21 are joined to both end portions of a band-shaped radiator 20 folded in half. Joining is preferably by welding or brazing. The radiator 20 is not limited to a metal plate folded in half, but may be a rod-like member or a linear member. However, in order to improve heat dissipation, it is preferable that the radiator 20 has a shape with a large surface area. In this case, the area of the joint base portion with the case 21 is preferably large, but a shape in which heat is efficiently transmitted to the tip portion is preferable.

  Since the case 21 is made of metal, when the heater main body 14 including the heat radiating body 20 is accommodated in the case 21, an electrical insulating sheet or the like is interposed on the contact surface of the case 21 with the electrodes 15, 15 and the heater main body 14. The The heater main body 14 is accommodated in the case 21 together with the electrode plates 15 and 15 to which the electric wirings 17 and 17 are connected, and is filled with a heat conductive mold material and bonded to the case 21.

  The assembled breather heater 13 is mounted in the breather tube 11. FIG. 5 is a perspective view of the breather heater 13 and the breather tube 11 showing the mounting process of the breather heater 13. The breather tube 11 includes a joint tube 18 and divided tubes 22 and 23 fitted to small diameter portions 18a and 18b at both ends of the joint tube 18. The joint tube 18 is preferably made of nylon or the like having an appropriate heat insulating property, and the divided tubes 22 and 23 are preferably made of rubber so that they can be easily fitted to the connection portions with the air cleaner 8 and the head cover 10.

  A seating surface 18c is formed in a flat shape at the intermediate portion of the joint tube 18 so that the flange 21A of the case 21 can be seated. A slot 18d extending along the longitudinal direction of the joint tube 18 is formed on the seating surface 18c. The radiator 20 and the case 21 are inserted into the joint tube 18 along the path 24 from the front end side of the radiator 20 using the slot 18d, and the edge of the upper open portion of the case 21, that is, the flange 21A is seated on the seating surface. Position so as to be seated on 18c. Thus, the heater main body 14 is disposed at the center of the cross section of the joint tube 18, and the radiator 20 is disposed in a state of extending along the longitudinal direction of the joint tube 18. The arrangement of the heater body 14 and the radiator 20 will be further described later.

  After attaching the breather heater 13 to the joint tube 18, the divided tubes 22 and 23 are fitted into the joint tube 18. The assembly of the breather heater 13 and the breather tube 11 assembled in this way is connected to the air cleaner 8 and the engine head cover 10 at both ends.

  FIG. 1 is a side sectional view of a breather tube incorporating a breather heater 13, and FIG. 2 is a front sectional view thereof. 5 denote the same or equivalent parts. In FIG. 1, the split tube 23 of the breather tube 11 is fitted into a blow-by gas receiving port 8 </ b> A that is a cylindrical protrusion formed in the air cleaner 8. As can be understood from FIG. 2, the breather heater 13 is disposed so as to protrude from the center of the cross section of the joint tube 18 with the flange 21 </ b> A of the case 21 supported on the edge of the slot 18 d. The radiator 20 protruding from the case 21 is arranged along the longitudinal direction of the breather tube 11, and the tip thereof extends to the base of the blow-by gas receiving port 8A. The breather tube 11 is covered with an outer tube 25 made of a heat insulating material. The outer tube 25 may cover the entire breather tube 11 as long as it covers at least the connecting portion between the divided tubes 22 and 23 and the joint tube 18 incorporating the heater main body 14 as illustrated. The outer tube 25 shields the open portion of the upper surface of the case 21 of the breather heater 13 from the external environment, and heat-insulates the breather tube 11 from the external low-temperature environment.

  According to the configuration shown in FIGS. 1 and 2, the breather heater 13 is assembled to the joint tube 18 in advance to form an assembly, and this assembly can be connected to the divided tubes 22 and 23 in a separate process. It is easy to install the breather heater 13 in the engine-driven generator.

  FIG. 6 is a cross-sectional view showing a modification of the attachment portion with the air cleaner 8. Depending on the layout of the air cleaner 8, the joint tube 18 may not be arranged linearly in the direction in which the tip of the blow-by gas receiving port 8 </ b> A extends. Therefore, in this modification, the joint tube 18 is formed in an elbow shape, that is, a curved pipe.

  The breather heater 13 is inserted inward from a slot 18d formed in the horizontal portion 18H of the elbow-shaped joint tube 18. The radiator 20 is joined to the side perpendicular to the longitudinal direction of the case 21, that is, to the bottom surface of the case 21 in order to extend from the vertical portion 18 </ b> V of the joint tube 18 to the blow-by gas inlet 8 </ b> A. The vertical portion 18 </ b> V of the breather tube 11 and the blow-by gas receiving port 8 </ b> A are connected by a split tube 23, and the horizontal portion 18 </ b> H of the breather tube 11 is connected to the split tube 22.

  Thus, by appropriately selecting the shape and size of the heat dissipating body 20 extended from the breather heater 13 and the extending direction, the heater body 14 of the breather heater 13 cannot be provided at a desired heating target site. In addition, the portion can be arbitrarily heated via the radiator 20 that extends along the breather tube 11.

  Further, a subassembly in which the breather heater 13 is incorporated in the joint tube 18 is formed, and the divided tubes 22 and 23 are assembled in the subassembly to form an assembly. Further, the assembly is connected to the air cleaner 8 or the head cover 10 of the engine. A blowby gas passage can be formed. Thus, since the breather heater 13 can be incorporated in the joint tube 18 in advance, the breather heater 13 can be easily attached.

  In addition, when the heat radiator 20 is provided in the breather heater 13, the heat radiation area can be increased. However, the present invention can also include an engine to which the breather heater that does not have the heat radiator 20 is applied.

  The present invention is not limited to the above-described embodiment, and can be appropriately modified based on a configuration in which the breather heater is disposed in the joint tube through at least a slot provided in the joint tube.

It is side surface sectional drawing of the breather tube which accommodated the breather heater which concerns on one Embodiment of this invention. It is front sectional drawing of the breather tube which accommodated the breather heater which concerns on one Embodiment of this invention. It is a perspective view of an engine drive type generator with a breather device concerning one embodiment of the present invention. It is an exploded view of a breather heater. It is a perspective view which shows the assembly process of a breather heater and a breather tube. It is sectional drawing which shows the attachment part of an air cleaner and a breather tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine drive type generator, 4 ... Engine, 5 ... Generator main body, 8 ... Air cleaner, 10 ... Head cover, 11 ... Breather tube, 15 ... Electrode plate, 17 ... Electric wiring, 18 ... Joint tube, 18c ... Case seating Surface, 18d ... slot, 20 ... radiator, 21 ... case, 22,23 ... divided tube, 25 ... outer tube

Claims (2)

In an engine with a breather device that introduces blow-by gas into the intake passage of the engine via the blow-by gas passage,
Of the blow-by gas passage, a breather tube that is an external passage portion of the engine is composed of a joint tube and divided tubes connected to both ends of the joint tube.
The joint tube has a slot formed along a longitudinal direction of the joint tube in the tube wall;
A case that has a flange that engages with the inner periphery of the slot, and is disposed so as to protrude inside the joint tube and accommodates a PTC heater as a heater body, and extends from the case in the longitudinal direction of the joint tube An engine with a breather device, comprising a breather heater including a heat radiator that dissipates heat generated by the heater body . 2. The engine with a breather device according to claim 1 , wherein a cylindrical heat insulator that covers at least the joint tube including the slot is provided in the breather tube .

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