JP2007032486A - Latent heat accumulator and engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a latent heat accumulator having simple construction for keeping the temperature of an engine as long as possible even when the engine is stopped after completing warm-up of the engine, and for avoiding cold start when restarting the engine. <P>SOLUTION: The latent heat accumulator 1 comprises a latent heat accumulating material storage chamber 4 installed in the engine 2 and storing a latent heat accumulating material 5, and a protruded part (a low temperature holding part 6) communicated with the latent heat accumulating material storage chamber 4 and led to the outside of the engine 2 for keeping at least part of the inside latent heat accumulating material 5 at a low temperature such as to be held in a solid-phase state. The liquid-phase latent heat accumulating material 5 mixed with the latent heat accumulating material 5 in the solid-phase state is subjected to a phase change from a liquid phase into a solid phase in the process of temperature drop. During the phase change, the temperature of the latent heat accumulating material 5 is kept almost constant, therefore suppressing the temperature drop of the engine 2. Thus, a longer time is gained before causing cold start. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a latent heat storage device that can effectively keep an engine warm.

  Since the engine has a problem such as a large friction when the warm-up is not completed, early warm-up is required. In particular, components having sliding portions such as cylinder bores, pistons, crankshafts, and the like are desired to complete early warm-up in order to realize efficient operation. When an in-cylinder explosion starts, a normal engine warms engine components such as cylinder blocks and cylinder heads, and engine oil that circulates in the oil passages formed in these engine components. Progresses. Conventionally, in order to achieve the early warm-up completion of such an engine, an engine rapid warm-up device in which a latent heat storage material (heat storage material) is stored in a heat storage material storage chamber formed so as to surround a cylinder has been proposed. (Patent Document 1). Such a rapid warm-up device is configured to apply a voltage to a heat storage material in a supercooled state when the engine is cold started, thereby starting a phase change and generating latent heat. .

JP 11-182393 A

  As described above, the rapid warm-up device for an engine described in Patent Document 1 can raise the temperature locally around the cylinder directly immediately after the cold start, and can efficiently raise the temperature of the engine. is there.

  However, the rapid warm-up device for an engine described in Patent Document 1 is concerned that the structure may be complicated, for example, an electrode for applying a voltage to the heat storage material must be attached. In addition, once the engine has been warmed up, if the engine is stopped, as long as the engine is at an appropriate temperature, a new warm-up operation is not required by operating the rapid warm-up device. It is.

  Therefore, the present invention provides a latent heat storage device that can maintain the engine temperature as much as possible even when the engine is stopped once the engine has been warmed up and that is unlikely to start cold during engine restart. Let it be an issue.

  In order to solve such a problem, the latent heat storage device of the present invention is installed in the engine, and communicates with the latent heat storage material storage chamber in which the latent heat storage material is stored, and the latent heat storage material storage chamber, And a protrusion that is led out of the engine and maintains a low temperature so as to hold at least a portion of the internal latent heat storage material in a solid phase state (Claim 1). In the present invention, a material having a large heat capacity is accommodated in an engine so that the temperature of the engine can be maintained for a long time even after the engine is stopped. As such a substance having a large heat capacity, a latent heat storage material such as sodium acetate trihydrate can be employed. Conventionally, such a latent heat storage material is similar to a material that generates heat by a nucleation operation and uses the heat to warm up the engine. However, the latent heat storage material in the present invention is used in a different manner from the conventional latent heat storage material, and the latent heat storage material in the present invention avoids being in a supercooled state, The temperature of the engine after the completion of warm-up is maintained (warming) as much as possible by changing the phase between the two. That is, there is almost no change in temperature during the phase change, and the purpose is to keep the engine warm by utilizing that temperature.

  In view of this, the present invention has a configuration that includes a protruding portion that is led out of the engine and maintains a low temperature so as to hold at least a portion of the internal latent heat storage material in a solid state, that is, a low temperature holding portion. . The latent heat storage material has a portion that is in a solid phase state even in a part of the latent heat storage material housed in the same room, that is, if the liquid phase and the solid phase are mixed, The existing latent heat storage material changes into a solid phase without being supercooled. The present invention utilizes this principle, and the projection portion encloses a solid-phase latent heat storage material therein so that the solid-phase latent heat storage material does not change to a liquid phase due to a temperature rise. In addition, it is configured as a portion led out of the engine in order to keep the temperature low (melting point or less).

  By the way, in order to prevent the latent heat storage material from being overcooled, it may be possible to add other substances. However, the latent heat utilization value may be reduced due to the lowering of the melting point, or the safety of the poisoning may be reduced. There is a risk of degrading. Moreover, when the added substance causes a chemical change due to a temperature change or the like, the effect of avoiding the supercooled state of the latent heat storage material may be lost. With the configuration of the present invention, it is possible to avoid a supercooled state of the latent heat storage material without causing such inconvenience.

  The latent heat storage material accommodation chamber in such a latent heat storage device is installed at a location where the heat of the engine can be held, but for example, it may be configured around a water jacket formed in the bore portion of the engine. (Claim 2). The latent heat storage material storage chamber has a certain height when disposed around the water jacket. In such a case, the protrusion (low temperature holding unit) is provided with the latent heat storage material storage. It is desirable that the latent heat storage material accommodation chamber communicates with the vicinity of the lower end of the chamber. The reason for this configuration is as follows. In the latent heat storage material storage chamber having a height, the volume of the internal latent heat storage material may decrease for some reason. In this case, if the protrusion is in communication with the latent heat storage material storage chamber above the liquid surface of the latent heat storage material, the solid phase latent heat storage material in the protrusion and the liquid phase latent heat in the latent heat storage material storage chamber The heat storage material is separated. If the solid phase latent heat storage material and the liquid phase latent heat storage material are separated in this way, there is a possibility that the transition to the supercooled state of the liquid phase state portion cannot be avoided. Therefore, if the protrusion is configured to communicate with the latent heat storage material storage chamber in the vicinity of the lower end of the latent heat storage material storage chamber, the solid phase latent heat storage material in the protrusion and the latent heat storage heat in the latent heat storage material storage chamber. Can be mixed with materials and kept together.

  As described above, the protrusions must keep the internal latent heat storage material in a solid state. Therefore, it is desirable to maintain a heat exchanger around the protrusion so that the latent heat storage material in the protrusion is kept at a predetermined temperature or lower so that it does not change to the liquid phase.

  Note that the engine of the present invention can be obtained by incorporating the latent heat storage device as described above into various engines.

  According to the present invention, the latent heat storage material storage chamber installed inside the engine and containing the latent heat storage material is communicated with the latent heat storage material storage chamber. And a protrusion that maintains a low temperature so as to hold at least a portion of the heat storage material in a solid state, so that the engine temperature is maintained for a long time while avoiding the overcooling state of the latent heat storage material. be able to.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  1 and 2 are schematic configuration diagrams showing a part of an engine 2 in which the latent heat storage device 1 of this embodiment is incorporated. 1 is a cross section taken along the line BB shown in FIG. 2, and FIG. 2 is a cross section taken along the line AA shown in FIG. A water jacket 3 through which cooling water flows is formed in the bore portion 2 a of the engine 2, and a latent heat storage material storage chamber 4 is disposed around the water jacket 3. In this latent heat storage material storage chamber 4, sodium acetate trihydrate which is the latent heat storage material 5 is stored. As sodium acetate trihydrate, those having melting points of about 58 ° C. and 89 ° C. can be used, but in this embodiment, those having 89 ° C. are used.

  The latent heat storage material accommodation chamber 4 is arranged along the cylinder 2a1 as shown in FIG. 2 and has a certain height. However, the latent heat storage material accommodation chamber 4 has a low temperature in the vicinity of the lower end 4a of the latent heat storage material accommodation chamber 4. A holding unit 6 is provided continuously. As shown in the drawing, the low temperature holding unit 6 is a protruding portion led out to the outside of the engine 2. That is, the low temperature holding part 6 corresponds to the protrusion in the present invention. A latent heat storage material 5 similar to that stored in the latent heat storage material storage chamber 4 is stored inside the low temperature holding unit 6. However, at least a part of the latent heat storage material 5 in the low temperature holding unit 6 is in a solid state. A heat exchanger 7 is disposed around the low temperature holding unit 6. With such a configuration, the latent heat storage material 5 in the low temperature holding unit 6 is held at a temperature equal to or lower than the melting point to maintain a solid state.

  A temperature change after stopping the engine 2 incorporating the latent heat storage device 1 configured as described above will be described in comparison with a conventional engine that does not include the latent heat storage device 1.

First, in the conventional engine without a latent heat storage apparatus 1 shown by the solid line, the temperature gradually decreases from the state of t ₀ immediately after the engine stop. On the other hand, in the engine 2 of this embodiment having the latent heat storage device 1 shown in broken lines, first, temperature gradually decreases from t _0, reaches t ₂ (I point). t ₂ is the melting point of the latent heat storage material 5. The process from t ₀ to t ₂ is a temperature decrease due to sensible heat, and follows a process similar to that of a conventional engine. Thereafter, the latent heat storage material 5 undergoes a phase change from the liquid phase to the solid phase between the points I and II. During this time, since the temperature is constant, the engine temperature is also maintained at a constant temperature. That is, the engine 2 is kept warm. Thereafter, it reaches point II where the phase change of the latent heat storage material 5 ends. After point II, the temperature starts to decrease again.

This because the process of temperature decrease are different as, after reduced time and elapsed same time until t ₁ the temperature of the conventional engine, the engine 2 of this embodiment are still holding the t ₃ (t 1 _{<t 3} ). If it caused to restart the engine in this timing, so that it is possible to improve the starting initiation temperature by ₁ minute Temperature T. If in the case where the engine is restarted during the phase change proceeds during the I point of latent heat storage material 5 to II points can improve startup initiation temperature only ₂ minutes the temperature T.

  As described above, the latent heat storage device 1 of the present invention can extend the time until the cold start, and improves the engine start start temperature when the engine is restarted within a relatively short time after the engine is stopped. Can be made. If the engine start start temperature can be improved, the fuel consumption can be improved by reducing the friction, and the exhaust composition can be improved. In addition, the latent heat storage device 1 of the present invention does not need to be equipped with a special nucleation device or the like, so it can be configured in a very simple manner and has excellent mountability to the engine.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

It is the schematic block diagram which showed a part of engine which incorporated the latent heat storage apparatus of the Example, and is made into the cross section by the BB line shown in FIG. It is the schematic block diagram which showed a part of engine which similarly incorporated the latent heat storage apparatus of the Example, and made it the cross section by the AA line shown in FIG. It is the figure which showed the mode of the engine temperature fall of an Example compared with the conventional engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Latent heat storage apparatus 2 Engine 2a Bore part 2a1 Cylinder 3 Water jacket 4 Latent heat storage material accommodation room 5 Latent heat storage material 6 Low temperature holding part 7 Heat exchanger

Claims (5)

A latent heat storage material storage chamber installed inside the engine, in which the latent heat storage material is stored;
A protrusion that communicates with the latent heat storage material storage chamber, is led out of the engine, and is maintained at a low temperature so as to maintain at least a portion of the internal latent heat storage material in a solid state;
A latent heat storage device comprising: The latent heat storage device according to claim 1,
The latent heat storage material storage chamber is disposed around a water jacket formed in a bore portion of an engine. The latent heat storage device according to claim 1 or 2,
The protrusion is in communication with the latent heat storage material storage chamber in the vicinity of the lower end of the latent heat storage material storage chamber. In the latent heat storage device according to any one of claims 1 to 3,
A latent heat storage device, wherein a heat exchanger is disposed around the protrusion. An engine comprising the latent heat storage device according to any one of claims 1 to 4.

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