JP2007224739A - Engine with breather device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain freezing of moisture of blow-by gas in a breather tube. <P>SOLUTION: A breather heater 13 being an electric heater is arranged in the breather tube 11. A heater element 14 being a body of the breather heater 13 is joined with an electric lead wire 16 on both ends, and is supported in the tube 11 by a piece 15 penetrated through the electric lead wire 16. The piece 15 is formed of rubber having resiliency, and is strutted and fixed between inner walls of the breather tube 11 by its resiliency. The piece 15 is easily compressively deformed from the periphery, and has a column part 15B radially expanded from a position of the lead wire 16 so as to secure an opening capable of passing the blow-by gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 in a breather tube efficiently, solving the said subject.

  In order to achieve the above object, the present invention provides an engine with a breather device for introducing blowby gas into an intake passage of an engine via a blowby gas passage, in a breather tube that is an external passage portion of the engine in the blowby gas passage. There is a first feature in that an electric heater disposed on the inner wall of the breather tube and supported by a heat insulating member is provided.

  The second feature of the present invention is that the heat insulating member is made of elastic rubber and is compression-inserted into the inner wall of the breather tube with a hole through which blow-by gas can pass. There is.

  Further, according to the present invention, the electric heater is provided such that its length direction is along the length direction of the breather tube, and is supported by the heat insulating member at two or more locations in the length direction of the breather tube. The point has the third feature.

  Furthermore, the present invention has a fourth feature in that the electric heater is a PTC heater whose periphery is sealed from the atmosphere in the breather tube.

  According to the present invention having the first to fourth characteristics, since the breather heater can be directly heated in the flow of the blow-by gas in the breather tube, freezing can be prevented efficiently. Further, since the heater element is thermally shielded from the breather tube, almost no heat is released to the outside air through the breather tube, and excess heating can be suppressed.

  According to the present invention having the second feature, the heat insulating member is stretched and supported between the inner walls of the breather tube by its own elasticity, so that the mounting structure can be simplified.

  According to the present invention having the third feature, the length direction of the electric heater can be made to follow the flow of blow-by gas flowing in the breather tube. The contact area with the flow can be increased, and the support structure is not complicated.

  According to the fourth feature, the PTC heater having a self-control function does not require external control, and the structure can be simplified.

  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). ).

  1 and 2 are cross-sectional views of the main part of the blow-by gas passage provided with the breather heater, and FIG. 4 is a cross-sectional view of the breather tube. FIG. 1 shows an example in which the breather heater is arranged in the breather tube, and FIG. 2 shows an example in which the breather heater is arranged in the connecting portion between the breather tube and the air cleaner.

  In FIG. 1, a breather heater 13 includes a heater element (preferably a PTC heater which is a semiconductor ceramic made of barium titanate) 14 and a set of two pieces as a holding member for fixing the heater element 14 in the breather tube 11. Fifteen. The heater element 14 has a columnar shape, and the length direction of the heater element 14 is arranged in the breather tube 11 along the length direction of the breather tube 11, that is, the gas flow direction. The heater element 14 is sealed around the PTC heater so that the PTC heater does not directly contact the blow-by gas. A current is supplied to the heater element 14 from a power source (not shown) through the electric lead wire 16. The PTC heater generates heat and increases its resistance when supplied with current. As a result, the current decreases, the temperature decreases, and the current increases again. Since the PTC heater has a self-temperature control function for maintaining the temperature substantially constant according to such temperature-resistance characteristics, a temperature control device can be dispensed with.

  The piece 15 has a hole 15A through which the electric lead wire 16 led out from both ends of the heater element 14 passes. The electric lead wires 16 and 16 are in contact with both end portions of the heater element 14 in a state of passing through the hole 15A. Are arranged. The piece 15 is made of an elastic material having a low thermal conductivity such as rubber, and has a plurality of column portions 15B projecting radially from the hole 15A toward the inner surface of the breather tube 11 as can be understood from FIG. The diameter of the circle inscribed on the outermost periphery of the column portion 15B (the outer diameter of the piece) is set slightly larger than the inner diameter of the breather tube 11. That is, the piece 15 is accommodated in the breather tube 11 in a state compressed from the outer periphery. As a result, the heater element 14 is set substantially at the center in the breather tube 11, and the heater element 14 and the breather tube 11 are held in a state of being thermally cut off.

  In FIG. 2, as in FIG. 1, the heater element 14 is arranged in the blow-by gas passage using the piece 15, but the arrangement position is a connection portion between the air cleaner 8 and the breather tube 11. The piece 15 is compression-fitted to the inner periphery of the blow-by gas receiving projection 8A formed in the air cleaner 8, and is held in the projection 8A by its elasticity.

  According to the breather heater 13 described above, the blow-by gas passing through the breather tube 11 is warmed by the heater element 14, and freezing of moisture in the blow-by gas is suppressed. In particular, since the heat generated by the heater element 14 by the piece 15 is made difficult to be transmitted to the wall of the breather tube 11, it is possible to prevent the heat from being diffused to the outside through the wall, and to prevent freezing of moisture. Can effectively use heat.

  In addition, the support | pillar part 15B provided in the piece 15 is not restricted to four as shown in FIG. In order to stably hold the heater element 14 in the tube 11 and to secure a gas passage, three to four are preferable, but two may be used. Further, as long as the piece 15 is insulated and held in the breather tube 11, it is not limited to a columnar shape such as the column portion 15B. For example, as shown in FIG. In addition, the outer periphery may have a large number of irregularities and a plurality of holes 15C through which gas can pass. Two pieces may be provided at both ends of the heater element 14, but the number may be further increased.

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 side surface sectional drawing of the connection part of the breather tube which accommodated the breather heater which concerns on one Embodiment of this invention, and an air cleaner. It is a perspective view of an engine drive type generator with a breather device concerning one embodiment of the present invention. It is AA sectional drawing of FIG. It is sectional drawing of the breather tube which accommodated the breather heater which concerns on a modification.

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, 14 ... Heater element, 15 ... Piece, 15B ... Strut part, 16 ... Electric lead wire

Claims (4)

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,
An engine with a breather device, comprising: an electric heater disposed in a breather tube that is an external passage portion of the engine in the blow-by gas passage and supported on an inner wall of the breather tube via a heat insulating member.   2. The breather apparatus according to claim 1, wherein the heat insulating member is made of elastic rubber and is compression-inserted into the inner wall of the breather tube with a hole through which blow-by gas can pass. With engine.   The electric heater is provided so that a length direction thereof is along a length direction of the breather tube, and is supported by the heat insulating member at two or more locations in the length direction of the breather tube. Item 3. The engine with a breather device according to Item 1 or 2. The engine with a breather device according to any one of claims 1 to 3, wherein the electric heater is a PTC heater whose periphery is sealed from the atmosphere in the breather tube.

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