JP2007077951A - Piston for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston for an internal combustion engine, whose cooling performance is greatly improved without the need for increasing its length and size. <P>SOLUTION: On the inner face of the piston, there are arranged a generating means consisting of a coil 7 and a magnet 8, a commutation circuit 14 consisting of a diode 12 electrically connected to the generating means and a capacitor 13, and a thermoelectric conversion means consisting of a thermoelectric conversion element 2 electrically connected to the commutation circuit 14 and a heat sink 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

 The present invention relates to a piston for an internal combustion engine.

  The piston (1) provided in the internal combustion engine is an engine part that defines a high-temperature combustion chamber at the top and converts the combustion pressure generated in the combustion chamber into the rotational force of the crankshaft through the connecting rod (5). Thermally in the most harsh environment.

  The top (11) of the piston (1) is exposed to high-temperature combustion gas, and the heat received at the top (11) is the piston ring (22, 23, 24) or skirt attached to the land (15). A heat dissipation path that escapes from (16) to the cylinder (2), a heat dissipation path that escapes to the connecting rod (5) via the piston pin (4), and a lubricating oil supplied between the piston (1) and the cylinder (2) There is a heat dissipation path taken away by. Furthermore, there is also an internal combustion engine provided with an oil jet that injects lubricating oil toward the back surface (19) of the piston (1), and added with a heat radiation path for removing the heat of the piston (1) by the lubricating oil. The piston (1) is cooled through these heat radiation paths.

  By the way, as one of the recent demands for automobile engines, the volume of the clevis sandwiched between the top land (31) and the cylinder (2) provided above the ring grooves (12, 13, 14) is reduced. In some cases, the quenching region in the combustion chamber is reduced, the amount of unburned gas in the engine is reduced, and the fuel consumption is improved.

  Alternatively, the land portion (15) tends to be downsized by reducing the width of each ring (22, 23, 24) or eliminating the compression ring (23) provided in the middle. As the piston (1) is reduced in size, the amount of heat released to the cylinder (2) is reduced, so that it is required to improve its cooling performance.

  However, if the land portion (15) is reduced in size as described above, the amount of heat released from the land portion (15) to the cylinder (2) via the rings (22, 23, 24) is reduced. There may be a problem that the cooling performance of the piston (1) deteriorates.

Therefore, in order to increase the heat radiation amount of the piston (1) carried away by the lubricant, the surface area of the piston (1) with respect to the lubricant supplied between the piston (1) and the cylinder (2) is increased. A piston (1) is known in which cooling fins (30) are formed so as to protrude between the land portion (15) and the skirt portion (16) while being inclined with respect to the axial direction of the piston (1). (For example, see Patent Document 1)
However, in response to an increase in thermal load accompanying an increase in engine output in recent years, an increase in the length of the piston is inevitable with the above-described method that relies on an expansion of the heat radiation area.
Japanese Patent Laid-Open No. 06-341346

  It is a technical object of the present invention to improve the cooling performance of a piston for an internal combustion engine piston without significantly increasing the length.

The first technical measure taken to solve the above problems is as follows:
A piston of the internal combustion engine that is provided in a reciprocating manner in a cylinder of the internal combustion engine and forms a combustion chamber with the cylinder;
Power generation means;
Current rectifying means electrically connected to the power generation means;
Thermoelectric conversion means electrically connected to the current rectification means,
It is arranged on the inner surface of the piston.

The second technical means is the first technical means,
The power generation means is composed of a coil wound around an axis parallel to the central axis of the piston and a magnet capable of reciprocating around the outer periphery of the coil.

The third technical means is the second technical means,
The magnet has a ring shape.

The fourth technical means is the first technical means,
In the thermoelectric conversion means, the low temperature portion of the thermoelectric conversion element is closely fixed to the top surface of the piston, and a heat sink is closely fixed to the high temperature portion of the thermoelectric conversion element.

 According to the invention of claim 1, by disposing the power generation means, the current rectification means, and the thermoelectric conversion means on the inner surface of the piston, a heat dissipation electric circuit for cooling can be configured in the reciprocating piston, so that the piston It will not be long.

 According to the invention of claim 2, since the power generation means is constituted by the coil wound around the axis parallel to the central axis of the piston and the magnet capable of reciprocating the outer periphery of the coil, the inertia due to the reciprocating motion of the piston The magnet reciprocates by force, and can generate alternating current.

 According to invention of Claim 3, since the magnet was made into ring shape, a coil can receive a magnetic force equally from outer periphery, and can generate | occur | produce the stable magnetic induction current.

 According to the invention of claim 4, the thermoelectric conversion means closely fixes the low temperature portion of the thermoelectric conversion element to the top surface of the piston and also fixes the heat sink to the high temperature portion of the thermoelectric conversion element. It can be cooled effectively.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a piston for an internal combustion engine according to the present invention will be described with reference to FIGS.

  On the inner top surface 1 a of the piston 1, for example, a thermoelectric conversion element 2 typified by a Peltier device is fixed in close contact with the inner top surface 1 a side of the piston 1 at a low temperature portion. Further, a heat sink 3 for radiating heat is closely fixed to the inner top surface 1 a of the piston 1 through the thermoelectric conversion element 2 by a fixing member 4 at a high temperature portion of the thermoelectric conversion element 2.

  A U-shaped support member 5 is fixed to the piston skirt inner surface 1b by a fixing member 6 in parallel with the piston axis. A coil 7 is wound around a portion parallel to the piston axis of the support member 5, and a ring-shaped magnet 8 is slidably held on the outer periphery of the coil 7.

  A magnet holder 9 that slidably holds the magnet 8 has a long plate shape integrally formed with a cylindrical sliding portion that encloses the magnet 8, and is fixed to the piston skirt inner surface 1 b by a fixing member 10. .

  At both ends of the coil 7, dampers 11 are disposed as stoppers for restricting the range of reciprocal movement while absorbing the impact when the magnet 8 reciprocates due to the inertial force due to the reciprocal movement of the piston.

  The coil 7 and the thermoelectric conversion element 2 are electrically connected and have a rectifier circuit 14 including a diode 12 and a capacitor 13 in the middle. An example of the circuit configuration is shown in FIG.

  The operation of the piston for the internal combustion engine of the present embodiment configured as described above will be described.

  The piston 1 defines a high-temperature combustion chamber at the top, and converts the combustion pressure generated in the combustion chamber into the rotational force of the crankshaft via a connecting rod (not shown). At that time, it reciprocates at a high speed in a cylinder (not shown).

  Since the magnet 8 is slidably held on the outer periphery of the coil 7, the magnet 7 reciprocates on the outer periphery of the coil 7 due to the inertial force generated by the reciprocating motion of the piston 1. Will occur. The alternating current is converted into a direct current by the rectifier circuit 14 and flows to the thermoelectric conversion element 2.

  A Peltier element known as the thermoelectric conversion element 2 is an element that utilizes the Peltier effect that heat is transferred from one metal to the other when an electric current is passed through a joint between two kinds of metals. When a DC voltage is applied, one side becomes low temperature and the other side becomes high temperature, and when the high temperature part is radiated, the low temperature part becomes further low temperature and functions as a so-called heat absorbing material. The low temperature portion is brought into close contact with the inner top surface 1a of the piston 1 to cool the inner top surface 1a of the piston 1, and the heat is dissipated by the heat sink 3 which is closely fixed to the high temperature portion, thereby cooling the piston 1 as a whole.

  In the present embodiment, half-wave rectification is described as an example of the circuit configuration, but it is needless to say that a full-wave rectification circuit configuration may be used.

It is sectional drawing of the piston to which this invention is applied. It is AA sectional drawing of FIG. It is an example of the circuit diagram to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piston 2 ... Thermoelectric conversion element 3 ... Heat sink 4 ... Fixing member 5 ... Supporting member 6 ... Fixing member 7 ... Coil 8 ... Magnet 9 ... Magnet Holder 10 ... fixing member 11 ... damper 12 ... diode 13 ... capacitor 14 ... rectifier circuit

Claims (4)

A piston of the internal combustion engine that is provided in a reciprocating manner in a cylinder of the internal combustion engine and forms a combustion chamber with the cylinder;
Power generation means;
Current rectifying means electrically connected to the power generation means;
Thermoelectric conversion means electrically connected to the current rectification means,
A piston for an internal combustion engine disposed on the inner surface of the piston. In claim 1,
The power generation means is a piston for an internal combustion engine comprising a coil wound around an axis parallel to the central axis of the piston and a magnet capable of reciprocating around the outer periphery of the coil. In claim 2,
The magnet is a piston for an internal combustion engine having a ring shape. In claim 1,
The thermoelectric conversion means is a piston for an internal combustion engine in which a low temperature portion of the thermoelectric conversion element is closely fixed to the top surface of the piston and a heat radiating plate is closely fixed to the high temperature portion of the thermoelectric conversion element.

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