JP2009203876A - Thermal engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve efficiency in a thermal engine using bending moment caused by deformation of a shape memory alloy. <P>SOLUTION: A material of which deformation temperature can be changed according to surrounding magnetic field is used for a material included in an endless belt 4. This engine is provided with a magnetic pole 7 (magnetic force apply means) arranged in such a manner that magnetic force can be applied on the endless belt 4, a hot water supplier 5 (heat apply means) arranged in such a manner that heat can be applied on the endless belt 4, and a controller 8 (control means) controlling the magnetic pole 7 according to an operation state of the hot water supplier 5. Energy efficiency of the thermal engine 1 can be improved by applying magnetic field on the endless belt 4 and controlling deformation temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat engine using a material having a shape memory characteristic that generates a restoring force to a shape stored in advance as the temperature rises above a deformation temperature.

  There has been proposed a shape memory alloy engine in which a shape memory endless belt is wound around a pair of pulleys. In the device described in Patent Document 1, when the heat applying means is arranged at a portion where the endless belt is unwound from one pulley and heated so as to exceed the deformation temperature, the endless belt is stored in a linear shape or A bending moment is generated to return to the inverted R shape, and a rotational force is generated based on this bending moment.

JP 2006-207441 A

  However, the apparatus of Patent Document 1 has a problem that the energy efficiency is lowered when the temperature of the heat applying means is lower than the deformation temperature, and the energy efficiency is not increased in a region higher than the deformation temperature.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel means for improving the efficiency of a heat engine that uses a bending moment accompanying deformation of a shape memory alloy.

  In order to solve the above problems, a heat engine according to the present invention is a pair of pulleys and an endless belt wound around the pair of pulleys, and has a shape memorized in advance as the temperature rises above the deformation temperature. And an endless belt including a material having shape memory characteristics that generates a restoring force of the material, wherein the deformation temperature of the material can be changed according to an ambient magnetic field.

  In the present invention, the material contained in the endless belt is a material whose deformation temperature can be changed according to the surrounding magnetic field. Therefore, by controlling the deformation temperature by applying a magnetic field to the endless belt, It becomes possible to improve the energy efficiency of the engine.

  In the present invention, it is preferable to further include magnetic force applying means arranged to be able to act on the endless belt. Further, the deformation temperature of the material is preferably lowered as the ambient magnetic field becomes stronger.

  Moreover, in this invention, it is suitable to further provide the heat provision means arrange | positioned so that it can act with respect to an endless belt, and the control means which controls the said magnetic force provision means according to the operation state of the said heat provision means.

  Embodiments of the present invention will be described below with reference to the drawings. The heat engine 1 according to the embodiment of the present invention shown in FIGS. 1 to 3 includes a low temperature side pulley 2 and a high temperature side pulley 3, an endless belt 4 wound around the pair of pulleys 2, 3, and an endless belt 4. Are provided with a hot water supply device 5, a cold water supply device 6, and a magnetic pole 7.

The low temperature side pulley 2 has a larger diameter than the high temperature side pulley 3 (r _c > r _h ). The axis of the low temperature side pulley 2 is arranged in parallel and vertically above the axis of the high temperature side pulley 3. The low temperature side pulley 2 is supported by a shaft 12 fixed to the support column 11 and is rotatable by a bearing 13 provided on the shaft 12. The high temperature side pulley 3 is fixed to the output shaft 14, and the output shaft 14 is rotatably supported by a bearing 15 provided on the support 11.

  The endless belt 4 contains a shape memory material. As the shape memory material used in the present embodiment, a material that generates a restoring force to a previously memorized shape with a temperature rise exceeding a certain deformation temperature is used. This deformation is considered to be accompanied by a transformation (reverse transformation) from the martensite phase (M phase) to the austenite phase (A phase).

  The shape memory material contained in the endless belt 4 has a characteristic that its deformation temperature changes according to the surrounding magnetic field. As shown in FIG. 3, the shape memory material used in the present embodiment undergoes transformation from the M phase to the A phase at a relatively high temperature as shown by the curve a in the non-excited state. The transformation temperature from the M phase to the A phase decreases as the surrounding magnetic field increases (curve-induced reverse transformation characteristics), as shown by the curve b in a strong magnetic field and the curve c in a strong magnetic field. The deformation of the shape memory material and the transformation from the M phase to the A phase are reversible and have a predetermined hysteresis. In this embodiment, this characteristic is used to change the transformation temperature from the M phase to the A phase by controlling the strength of the magnetic field.

  As such a shape memory material, a NiMnIn alloy, a NiCoMnIn alloy, a NiMnSn alloy, or a NiMnSb alloy is preferably used, but other materials may be used. Such a shape memory material is obtained by inductively heating particulate raw materials mixed at a desired mass ratio in an argon atmosphere, slicing the resulting ingot, and homogenizing at 1000 ° C for one day in a vacuum. After that, it can be obtained by quenching in water.

  As shown in FIG. 4, the endless belt 4 in the present embodiment is formed by alternately laminating layers 4p made of a shape memory material foil or a single crystal and an elastomer layer 4q, and deformed into a saw-tooth shape or a zigzag shape. It has a ribbon shape. Endless belt 4 is in a stretched state in which pitch p, which is the interval between adjacent valleys, takes a relatively large value at room temperature, and is higher than the deformation temperature (for example, 100 ° C. in a non-excited state). Is preliminarily stored in a shape so as to be in a degenerated state having a relatively small value.

  The hot water supply device 5 can supply hot water such as engine cooling water from an on-vehicle radiator (not shown) to the endless belt 4 continuously or intermittently. Hot water from the hot water supplier 5 is supplied to a linear portion 4 h of the endless belt 4 from the low temperature side pulley 2 to the high temperature side pulley 3.

  The cold water feeder 6 can supply cold water from a cold water tank (not shown), for example, continuously or intermittently toward the endless belt 4. The cold water from the cold water feeder 6 is supplied to a portion 4 c that is lower in temperature than the hot water and extends from the high temperature side pulley 3 to the low temperature side pulley 2 in the endless belt 4.

  The magnetic pole 7 is disposed outside the endless belt 4 along the entire travel path, and the magnetic field can be applied to the endless belt 4. The magnetic pole 7 is fixed to the magnetic pole base 16, and the magnetic pole base 16 and the column 11 are fixed to the base 17.

  The magnetic pole 7 has an iron core 7a and a coil 7b fixed therein. The coil 7b is connected to the controller 8 and a power source (not shown). The controller 8 is a one-chip microprocessor having a CPU, a ROM, a RAM, and an input / output interface connected to each other by a data bus. A detection signal from the temperature sensor 9 is input to the input interface of the controller 8. The temperature sensor 9 detects the temperature of the endless belt 4 in the vicinity of the hot water supply point by the hot water supply device 5, and for example, an infrared non-contact thermometer (radiation thermometer) is preferably used.

  The current supplied from the power source to the coil 7b is controlled by the controller 8. For this control, a temperature-excitation current map (see FIG. 5) in which the temperature of the endless belt 4 and the output current to the coil 7b are stored in association with each other is stored in advance in the ROM of the controller 8. In this temperature-excitation current map, the relationship between the two is set so that the output current value to the coil 7b gradually increases as the detected temperature of the endless belt 4 gradually decreases.

  In the above configuration, when the hot water from the hot water supply device 5 is supplied to the high temperature portion 4h of the endless belt 4 and the cold water from the cold water supply device is supplied to the low temperature portion 4c of the endless belt 4, the high temperature portion 4h. At least a portion of the temperature rises above the deformation temperature of the shape memory material contained therein, the endless belt is deformed into a pre-stored degenerated state, and the magnetic properties of the shape memory material change from the M phase to the A phase. Change. On the other hand, the temperature of at least a part of the low temperature portion 4c is lowered below the deformation temperature and the transformation temperature by cooling, and returns to the extended state and the M phase.

  The bending moment accompanying the degeneration of the high temperature portion 4h acts in the direction in which the low temperature side pulley 2 and the high temperature side pulley 3 are rotated in the opposite direction, but the radius rc of the low temperature side pulley 2 is larger than the radius rh of the high temperature side pulley 3. Therefore, the low temperature side torque Fc is larger than the high temperature side torque Fh, and the endless belt 4 generates a rotational force in the R direction in the figure. Therefore, the heat engine 1 rotates in the R direction in the figure while the supply of hot water and cold water continues.

  Here, when the temperature of the endless belt 4 becomes lower than the deformation temperature at the time of non-excitation, the coil 7b of the magnetic pole 7 is excited by the control of the controller 8, and the magnetic field is strengthened. As the magnetic field gradually increases, the transformation temperature from the M phase to the A phase decreases, and as shown in FIG. 6, the energy efficiency curve corresponds to the curve b in FIG. After passing through the efficiency ηb in a medium magnetic field, the temperature gradually shifts to the low temperature side as the efficiency ηc in a strong magnetic field corresponding to the curve c in FIG. As a result, the operating efficiency of the apparatus is from the curve ηa (curve pqu) when no excitation by the magnetic pole 7 is performed, to the curve pqr-s-s that is an envelope of the curves ηa, ηb, and ηc. As a result, the energy efficiency is improved by a portion corresponding to the difference between the two (ie, the hatched area in FIG. 6).

  As described above, in the first embodiment, the material included in the endless belt 4 is a material whose deformation temperature can be changed in accordance with the surrounding magnetic field. Therefore, the endless belt 4 is deformed by applying a magnetic field. By controlling the temperature, the energy efficiency of the heat engine 1 can be improved.

  Moreover, in this embodiment, the magnetic pole 7 (magnetic force provision means) arrange | positioned so that it can act with respect to the endless belt 4, the hot water supply device 5 (heat provision means) arrange | positioned so that it can act with respect to the endless belt 4, and hot water supply Since the controller 8 (control means) for controlling the magnetic pole 7 in accordance with the operating state of the device 5 is further provided, the desired effect of the present invention can be obtained with a simple configuration.

  Although the temperature sensor 9 detects the temperature of the endless belt 4 in the first embodiment, the temperature sensor detects the temperature of the hot water supply device 5 as a heat source, and the controller 8 executes an estimation calculation. The temperature value of the endless belt 4 may be acquired. Further, the temperature value of the endless belt may be estimated from other parameters indicating the state of the vehicle.

  In the first embodiment, according to the temperature-excitation current map (see FIG. 5), the relationship between the two is set so that the output current to the coil 7b changes continuously according to the temperature change of the endless belt 4. In the present invention, the change in the output current in response to the temperature change may be not continuous but discrete.

  Next, a second embodiment of the present invention will be described. The heat engine 101 according to the second embodiment shown in FIGS. 7 to 10 uses a magnetic pole 107 having a permanent magnet 107b instead of the magnetic pole 7 in the first embodiment. The magnetic pole 107 is disposed so as to cover at least a part of the high temperature portion 4 h to which hot water is supplied by the hot water supplier 5. The magnetic pole 107 can be moved in the protruding and retracting directions by the actuator 110.

  As shown in more detail in FIGS. 8 and 9, the magnetic pole 107 includes two iron cores 107 a facing both side edges of the endless belt 4, and an outer side (pulley) of the endless belt 4 sandwiched between the two iron cores 107 a. 2 and 3 on the opposite side) of the permanent magnet 107b. The actuator 110 is, for example, a combination of a screw shaft and a nut that are rotationally driven by a servo motor. Due to the action of the actuator 110, the magnetic pole 107 approaches the endless belt 4 as shown in FIG. 9, and moves away from the endless belt 4 at the first position where the endless belt 4 becomes a part of the magnetic path of the permanent magnet 107b. Is driven steplessly in the direction A in the figure.

  For example, the controller 108 of the second embodiment reduces the deviation between the target rotational speed that is predetermined according to the detection value of the temperature sensor 9 and the actual rotational speed of the output shaft 14 detected by the rotational speed sensor 109. Next, the actuator 110 is controlled. Since the remaining configuration of the second embodiment is the same as that of the first embodiment, the same reference numerals are given and detailed description thereof is omitted.

  In the above configuration, when the hot water from the hot water supply device 5 is supplied to the high temperature portion 4h of the endless belt 4 and the cold water from the cold water supply device is supplied to the low temperature portion 4c of the endless belt 4, The endless belt 4 rotates in the R direction in the figure by the same operation as in the embodiment.

  Here, as shown in FIG. 10, the characteristic of the endless belt 4 as a whole in the non-excited state is a curve a, and the entire endless belt 4 is placed in a magnetic field corresponding to the time when the magnetic pole 107 protrudes (when approaching). Assuming that the characteristic in the state is a curve d, the endless belt 4 in the second embodiment is excited by at least a part of the high temperature part 4h by the magnetic pole 107, so that the characteristic is shown by a dotted line in FIG. In addition, the temperature rises steeply in the vicinity of the minimum temperature Tth of the high temperature portion 4h (symbol e), and after almost 100% becomes the A phase, it gradually shifts to the M phase (symbol f). The area of the region surrounded by the hysteresis loop in this characteristic curve is considered to correspond to the energy loss of the apparatus. In the second embodiment, the area of the region surrounded by the hysteresis loop by the excitation of the magnetic pole 107 is the curve a. It becomes smaller than the said area in the characteristic of the non-excitation state shown by. Therefore, in the second embodiment, the energy efficiency of the apparatus can be improved by using the magnetic pole 107.

  Next, a third embodiment of the present invention will be described. In the third embodiment, the transformation temperature of the shape memory material in the endless belt 4 is controlled so as to control the position of the magnetic pole 107 according to the temperature of the high temperature portion 4h of the endless belt 4 and to compensate for the decrease in temperature. Is. Since the mechanical configuration of the third embodiment is the same as that of the second embodiment described above and only differs in control, the same members will be described using the same reference numerals.

  The controller 108 of the third embodiment controls the position of the magnetic pole 107 by controlling the operation of the actuator 110. For this control, the ROM of the controller 108 stores in advance a temperature-magnetic pole position map (see FIG. 11) in which the temperature of the endless belt 4 and the position of the magnetic pole 107 are stored in association with each other. In this temperature-magnetic pole position map, the relationship between the two is set such that the position of the magnetic pole 107 approaches the endless belt 4 as the detected temperature of the endless belt 4 gradually decreases.

  In the above configuration, when the hot water from the hot water supply device 5 is supplied to the high temperature portion 4h of the endless belt 4 and the cold water from the cold water supply device is supplied to the low temperature portion 4c of the endless belt 4, The endless belt 4 rotates in the R direction in the figure by the same operation as in the embodiment.

  Here, when the temperature of the endless belt 4 becomes lower than the deformation temperature at the time of non-excitation, the magnetic pole 107 is brought close to the endless belt 4 by the control of the controller 108, and the magnetic field acting on the endless belt 4 is strengthened. As the magnetic field gradually increases, the transformation temperature from the M phase to the A phase decreases, and as shown in FIG. 6, the energy efficiency curve corresponds to the curve b in FIG. After passing through the efficiency ηb in a medium magnetic field, the temperature gradually shifts to the low temperature side as the efficiency ηc in a strong magnetic field corresponding to the curve c in FIG. As a result, the operating efficiency of the apparatus is from the curve ηa (curve pqu) when no excitation by the magnetic pole 107 is performed to the curve pqr-s-s which is an envelope of the curves ηa, ηb, and ηc. As a result, the energy efficiency is improved by a portion corresponding to the difference between the two (ie, the hatched area in FIG. 6).

  As described above, in the third embodiment, the transformation of the shape memory material in the endless belt 4 is controlled so as to control the position of the magnetic pole 107 according to the temperature of the high temperature portion 4h of the endless belt 4 and compensate for the temperature decrease. Since the temperature is controlled, the desired effect of the present invention can be obtained with a simple configuration.

  In the above embodiments, the present invention has been described with a certain degree of concreteness, but various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention described in the claims. It must be understood that it is possible. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents. For example, although the endless belt in each of the above embodiments uses a shape in which the retracted state is memorized, it may be a shape in which the stretched state is conversely memorized.

  Moreover, although the endless belt in each said embodiment used what expands-contracts according to temperature, this invention memorize | stored the endless belt in the vicinity of the extraction | feeding point of the belt from a pulley like the said patent document 1. The present invention can also be applied to a heat engine in which a rotational force is generated based on a bending moment for returning to a linear shape or a reverse R shape. In this case, the same magnetic pole 7 as that in the first embodiment or the same magnetic pole 107 as that in the second and third embodiments so as to cover a part or all of the entire travel path of the endless belt. By arranging the above and controlling them in the same manner as described above to change the magnetic field strength, it is possible to obtain the expected effect of the present invention.

  Further, as the heat applying means, a heat source other than the engine cooling water, for example, an engine exhaust pipe, an oil pan, or a dedicated heater may be used, and such a modification belongs to the category of the present invention.

It is a front view showing a schematic structure of a heat engine of a 1st embodiment of the present invention. It is a side view which shows the longitudinal cross-section of 1st Embodiment. It is a graph which shows the change by the magnetic field of the temperature state characteristic of the material used suitably for 1st Embodiment. It is a perspective view which shows the endless belt in 1st Embodiment. It is a graph which shows the example of a setting of the temperature-excitation current map used in 1st Embodiment. It is a graph which shows the energy efficiency curve in 1st Embodiment. It is a front view which shows schematic structure of the heat engine of 2nd Embodiment. It is a side view which shows the structural example of the magnetic pole in 2nd Embodiment. It is IX-IX sectional drawing of FIG. 8 which shows the magnetic pole in 2nd Embodiment. It is a graph which shows the temperature state characteristic of the material used suitably for 2nd Embodiment. It is a graph which shows the example of a setting of the temperature-magnetic pole position map used in 3rd Embodiment.

Explanation of symbols

1,101 Heat engine 2 Low temperature side pulley 3 High temperature side pulley 4 Endless belt 5 Hot water supply device 6 Cold water supply device 7, 107 Magnetic pole

Claims (3)

An endless belt comprising a pair of pulleys and an endless belt wound around the pair of pulleys, the material having a shape memory characteristic that generates a restoring force to a previously memorized shape with a temperature rise exceeding a deformation temperature And comprising
The heat engine characterized in that the deformation temperature of the material can be changed according to an ambient magnetic field. The heat engine according to claim 1,
Magnetic force applying means arranged to act on the endless belt;
The heat engine, wherein the deformation temperature of the material decreases as the surrounding magnetic field increases. The heat engine according to claim 1 or 2,
Heat applying means arranged to be operable with respect to the endless belt;
Control means for controlling the magnetic force application means according to the operating state of the heat application means;
A heat engine characterized by further comprising:

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