JP2016098930A - High pressure accumulator of automobile, and regeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automobile superior in energy recovery efficiency by utilizing temperature change generating in a high pressure accumulator.SOLUTION: A high pressure accumulator 23 of an automobile C is connected to an oil pump motor 13 and stores an oil and a gas under pressure. A piston 14b is disposed to divide the inside of a container 14a into an oil chamber OR and a gas chamber GR. In the oil chamber OR, an oil of variable storage amount is stored, and in the gas chamber GR, a gas of constant amount is stored. Thermoelectric elements 25a, 25b generating power by utilizing temperature difference, are disposed at a peripheral region of the gas chamber GR.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an automobile regeneration system using a high-pressure accumulator.

  The basic structure of this type of regeneration system will be described with reference to FIG.

  FIG. 1 is a simplified drive system for an automobile equipped with a regenerative system ERS, and shows a state where the vehicle is running with the engine 1 as a power source (the power source may be a motor). An output shaft of the engine 1 is connected to drive wheels 5 via an engine clutch 2, a transmission 3, and a differential gear 4, and the drive wheels 5 are rotationally driven by the engine 1.

  The regenerative system ERS includes a coupling mechanism 11, a motor clutch 12, an oil pump motor 13, a high pressure accumulator 14, a low pressure reservoir 15, and the like. The rotation shaft of the oil pump motor 13 is connected to the output shaft to the drive wheels 5 via the motor clutch 12 and the connection mechanism 11. The motor clutch 12 is in a disconnected state.

  The oil pump motor 13 is connected between a high-pressure accumulator 14 and a low-pressure reservoir 15 that store oil in communication with each other. The oil pump motor 13 has both functions of an oil pump and a hydraulic motor, and can be used as either one of the devices. The high pressure accumulator 14 stores high pressure oil at a level of several hundred atmospheres, and the low pressure reservoir 15 stores low pressure oil at a level of several atmospheres to several tens of atmospheres.

  As shown in FIG. 2, the high pressure accumulator 14 includes a container 14a having pressure resistance and a piston 14b that freely slides inside the container 14a. The inside of the high pressure accumulator 14 is partitioned into an oil chamber OR and a gas chamber GR by a piston 14b. If the capacity of the oil chamber OR increases due to the sliding of the piston 14b, the capacity of the gas chamber GR decreases accordingly, and if the capacity of the oil chamber OR decreases, the capacity of the gas chamber GR increases accordingly.

  The oil chamber OR communicates with the oil pump motor 13, and oil that moves between the low pressure reservoir 15 is stored. Therefore, the amount of oil stored in the oil chamber OR changes according to the operation of the oil pump motor 13.

  On the other hand, the gas chamber GR is sealed and a certain amount of gas is stored therein.

  As shown in FIG. 3A, during braking such as downhill traveling, the engine clutch 2 is disengaged and the motor clutch 12 is connected, whereby the power of the drive wheels 5 is input to the oil pump motor 13.

  Thereby, the oil pump motor 13 is driven as an oil pump, and the oil in the low pressure reservoir 15 is sent to the high pressure accumulator 14. As a result, the internal pressure of the high pressure accumulator 14 rises and higher pressure oil is accumulated (regeneration).

  At that time, the piston 14b slides from the oil chamber OR toward the gas chamber GR.

  As shown in FIG. 3B, when starting the automobile, the oil in the high pressure accumulator 14 flows out toward the low pressure reservoir 15 with the motor clutch 12 engaged. The oil pump motor 13 is driven as a hydraulic motor by the oil discharge pressure, and the power is output to the drive wheels 5 (powering).

  At that time, the piston 14b slides from the gas chamber GR toward the oil chamber OR.

  An example of such a regeneration system is disclosed in Patent Document 1, for example. An example of the high pressure accumulator 14 is disclosed in Patent Document 2, for example.

  Regarding the present invention, the basic content of the maximum power point tracking control is disclosed in, for example, Patent Document 3.

JP 2013-189084 A Special table 2008-512616 gazette JP 2005-222863 A

  During regeneration, energy loss occurs due to temperature changes in the high pressure accumulator.

  In FIG. 4, an example of the temperature change in the high voltage | pressure accumulator at the time of regeneration is shown. The broken line represents the change in vehicle speed, and the solid line represents the temperature change in the high pressure accumulator.

  When the vehicle speed is rapidly decelerated and oil is sent to the high pressure accumulator at once, the piston slides to the gas chamber side and the gas in the gas chamber is compressed (adiabatic compression). Thereby, the pressure and temperature of the gas rise, and the temperature of the high-pressure accumulator rises at a stretch as the heat is transmitted.

  Thereafter, the temperature of the high pressure accumulator gradually decreases due to heat dissipation and returns to room temperature. As a result, the energy stored in the high-pressure accumulator is reduced by the amount of heat energy that is lost due to heat dissipation than before the regeneration.

  For example, when the vehicle speed is suddenly reduced by 60 km / h, the temperature of the high pressure accumulator rises to near 80 ° C.

  Further, since oil flows out from the high pressure accumulator during power running, the temperature change of the high pressure accumulator also occurs at that time.

  That is, when oil flows out from the high-pressure accumulator at once, the piston slides to the oil chamber side and the gas in the gas chamber expands (adiabatic expansion). Thereby, since the pressure and temperature of gas fall, a high pressure accumulator is cooled. For example, the temperature of the high pressure accumulator can decrease from room temperature to −20 ° C.

  Accordingly, an object of the present invention is to provide an automobile having excellent energy recovery efficiency by utilizing a temperature change generated by a high pressure accumulator.

  The disclosed high-pressure accumulator is an automobile high-pressure accumulator that is connected to an oil pump motor that functions as one of an oil pump and a hydraulic motor and stores oil and gas under pressure.

  The high-pressure accumulator includes a pressure-resistant container and a piston that is slidably disposed inside the container and divides the interior of the container into an oil chamber and a gas chamber in a sliding direction. The oil chamber stores oil whose storage amount changes according to the operation of the oil pump motor, and the gas chamber stores a certain amount of gas. And the thermoelectric element which produces electric power using a temperature difference is installed in the peripheral part of the said gas chamber.

  According to this high pressure accumulator, the piston slides with a change in the amount of oil stored in the oil chamber, and the capacity of the gas chamber changes in size. When the gas sealed in the gas chamber is compressed or expanded all at once, the temperature of the gas chamber changes. Since a thermoelectric element that generates electric power by utilizing a temperature difference is installed in the peripheral part of the gas chamber, it is possible to convert the thermal energy accompanying the temperature change of the gas into electric energy and recover it.

  For example, the thermoelectric element may be installed on at least one of a surface layer portion of the piston facing the gas chamber and an end surface portion of the gas chamber facing the surface layer portion.

  Then, the temperature change of the gas chamber can be directly transmitted to the thermoelectric element, so that power can be generated efficiently.

  When configuring an automobile regeneration system using such a high-pressure accumulator, the following is preferable.

  The regenerative system includes the above-described high-pressure accumulator, a storage battery electrically connected to the thermoelectric element, and a polarity switching circuit electrically interposed between the thermoelectric element and the storage battery. When the oil pump motor functions as an oil pump, oil flows out of the high pressure accumulator during regeneration when the oil flows into the high pressure accumulator and when the oil pump motor functions as a hydraulic motor. At the time of power running, the polarity switching circuit reverses the polarity of the electromotive force output from the thermoelectric element to the storage battery.

  During regeneration, the temperature of the gas chamber increases, and during powering, the temperature of the gas chamber decreases. Therefore, during regenerative operation and power running, a temperature difference associated with the temperature change of the gas chamber acts on the thermoelectric element, so an electromotive force is generated in the thermoelectric element. However, the temperature difference acting on the thermoelectric element is higher or lower than that during regeneration. It is reversed with time. For this reason, the polarity of the electromotive force generated in the thermoelectric element is also reversed between regeneration and power running.

  On the other hand, according to this regenerative system, the polarity switching circuit inverts the polarity of the electromotive force output from the thermoelectric element during regeneration and powering, so that the electromotive force is always output to the storage battery with a constant polarity. Is possible. Therefore, since heat energy can be recovered both during regeneration and during power running, energy recovery efficiency can be improved.

  In this case, it is preferable to further intervene a current adjustment circuit downstream of the polarity switching circuit and perform maximum power point tracking control by the current adjustment circuit.

  If it does so, even if the temperature change which acts on a thermoelectric element is sudden, since electric power can be output efficiently, the recovery efficiency of energy can be improved further.

  According to the high-pressure accumulator and the like of the present invention, it is possible to provide an automobile excellent in energy recovery efficiency.

It is the schematic which shows an example of the regeneration system of a motor vehicle. It is a schematic sectional drawing which shows the basic structure of a high voltage | pressure accumulator. It is the schematic explaining the regeneration control of a motor vehicle. (A) has shown the state at the time of regeneration, (b) has shown the state at the time of power running, respectively. It is a graph which shows an example of the temperature change in the high pressure accumulator at the time of regeneration. It is the schematic which shows the outline | summary of the motor vehicle which mounted the regeneration system of this embodiment. It is a schematic sectional drawing which shows the structure of the high voltage | pressure accumulator of this embodiment. It is a figure explaining the principal part of a regeneration system. (A) has shown the connection state at the time of regeneration, (b) has shown the connection state at the time of power running, respectively. It is a graph which shows the relationship between the electric power obtained with a thermoelectric element, and an electric current. It is a graph which shows an example of the temperature change of the high voltage | pressure accumulator corresponding to the driving | running | working pattern of a motor vehicle. It is a figure explaining operation | movement of a polarity switching circuit. (A) has shown the electromotive force which a thermoelectric element generate | occur | produces at the time of regeneration and power running. (B) has shown the electromotive force output from a polarity switching circuit. It is a schematic sectional drawing which shows the modification of a high voltage | pressure accumulator.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following description is merely illustrative in nature and does not limit the present invention, its application, or its use.

(Configuration of regenerative system)
In FIG. 5, the outline | summary of the motor vehicle C which mounted the regeneration system ERS of this embodiment is shown. Since the basic configuration is the same as that of the automobile shown in FIG. 1, the same reference numerals are used for the configurations having the same functions, and the description thereof is omitted.

  The regenerative system ERS is further provided with a polarity switching circuit 20, a current adjustment circuit 21, a battery 22 (an example of a storage battery), and the like. The high pressure accumulator of the regenerative system ERS is partially different in structure from the high pressure accumulator 14 (referred to as a power generation type high pressure accumulator 23).

  The power generation type high pressure accumulator 23 is electrically connected to the battery 22 and ACC (accessory power source). The polarity switching circuit 20 and the current adjusting circuit 21 are electrically connected between the power generation type high pressure accumulator 23, the battery 22 and the ACC, and are connected in series in this order from the power generation type high pressure accumulator 23 side.

  FIG. 6 shows a power generation type high pressure accumulator 23. In this power generation type high pressure accumulator 23, a surface layer portion 23a of the piston 14b facing the gas chamber GR, and an end surface portion 23b of the container 14a (a portion facing the surface layer portion 23a and facing the gas chamber GR), Are provided with thermoelectric elements 25a and 25b (these are also referred to as piston side element 25a and end face side element 25b).

  The thermoelectric elements 25a and 25b have a function of generating power using a temperature difference. That is, an electromotive force is generated by a so-called Seebeck effect by using a thermoelectric element material that generates a potential difference by giving a temperature difference.

  Since the structures of the thermoelectric elements 25a and 25b themselves are known, detailed description thereof is omitted here. However, in the case of this regenerative system ERS, the thermoelectric element material is preferably a bismuth-tellurium-based material containing bismuth and tellurium as elements.

  As will be described later, the thermoelectric elements 25a and 25b are used near normal temperature in both the minus temperature range and the plus temperature range, such as −20 ° C. and 80 ° C. On the other hand, bismuth-tellurium-based thermoelectric element materials are suitable for this temperature range, and thus can exhibit excellent power generation performance.

  Each thermoelectric element 25a, 25b is installed with one of a pair of working surfaces receiving the temperature difference facing the gas chamber GR. The working surface facing the gas chamber GR may not be exposed to the gas chamber GR, but in that case, it is preferably disposed in the vicinity of the gas chamber GR.

  Each pair of lead-out wirings p1, p2, t1, and t2 for outputting the electromotive force generated in the thermoelectric elements 25a and 25b is led out of the power generation type high-pressure accumulator 23 through the through hole 27 opened in the end face portion 23b. ing. The through hole 27 through which the lead-out wirings p1, p2, t1, and t2 are inserted is sealed by a sealing member 28. The lead-out wirings p1, p2, t1, and t2 may be electrically connected to the outside of the power generation type high-pressure accumulator 23 through a relay terminal.

  The lead-out wirings p1 and p2 of the piston-side element 25a are accommodated in a bent state in the gas chamber GR so that the piston 14b does not extend even if the piston 14b slides to the limit toward the oil chamber OR. . The end face side element 25 b is formed with an introduction hole 29 that penetrates a pair of working surfaces, and the lead-out wirings p 1 and p 2 are led to the through hole 27 through the introduction hole 29.

  As shown in FIG. 7, each lead-out wiring p <b> 1, p <b> 2, t <b> 1, t <b> 2 drawn from the power generation type high pressure accumulator 23 is connected to the polarity switching circuit 20.

  Specifically, out of the derived wirings p1, p2, t1, and t2, the derived wirings p1 and t1 having the same polarity of the electromotive force generated in each thermoelectric element 25a and 25b corresponding to the temperature change of the gas chamber GR are derived. The wirings p2 and t2 are connected to each other, aggregated into a pair of output wirings s1 and s2, and then connected to the polarity switching circuit 20. In FIG. 7, the piston side element 25 a and the end face side element 25 b are simplified as one thermoelectric element.

  Each of the output wirings s1 and s2 is connected to the pair of relay wirings h1 and h2 by the polarity switching circuit 20 so that they can be switched alternately.

  In the polarity switching circuit 20 of the present embodiment, two switching terminals including a regeneration side terminal 20a and a power running side terminal 20b are provided, and the output wirings s1 and s2 are branched to regenerate one switching terminal. The side terminal 20a is connected to the power running side terminal 20b of the other switching terminal. Each relay wiring h1, h2 is connected to the switch terminal 20c of each switching terminal, and each switch terminal 20c switches electrical connection between the regeneration side terminal 20a and the power running side terminal 20b of each switching terminal.

  (A) of FIG. 7 represents the connection state at the time of regeneration, and each switch terminal 20c is connected to each regeneration side terminal 20a. (B) of FIG. 7 represents the connection state at the time of power running, and each switch terminal 20c is connected to each power running side terminal 20b.

  As described above, the polarity switching circuit 20 alternately switches the connection between the pair of output wirings s1 and s2 and the pair of relay wirings h1 and h2 between regeneration and power running, and thus is output from the thermoelectric elements 25a and 25b. The polarity of the electromotive force is reversed between regeneration and power running.

  The pair of relay wirings h <b> 1 and h <b> 2 are connected to the current adjustment circuit 21. The current adjustment circuit 21 has a function of performing maximum power point tracking control. In the maximum power point tracking control, the electrical operating point is adjusted so that the maximum power generation amount can be obtained with respect to the electromotive force of the fluctuating thermoelectric elements 25a and 25b.

  FIG. 8 shows the relationship between electric power and current obtained by the thermoelectric elements 25a and 25b. In the thermoelectric elements 25a and 25b, the electric resistance increases as the current flowing through the thermoelectric element material increases, so that there is a peak in the obtained power. Therefore, in this current adjustment circuit 21, maximum power point tracking control is performed so that the thermoelectric elements 25a and 25b operate at the maximum power point indicating the peak.

  The current adjustment circuit 21 is connected to the battery 22 and the ACC through the power transmission line k. The electromotive force whose output is adjusted by the current adjustment circuit 21 is transmitted to the battery 22 and the ACC through the transmission line k.

(Operation of regenerative system ERS)
FIG. 9 shows an example of a temperature change of the power generation type high pressure accumulator 23 corresponding to the traveling pattern of the automobile C. A broken line represents a change in vehicle speed, and a solid line represents a temperature change in the power generation type high pressure accumulator 23.

  When the vehicle speed is suddenly decelerated and the regeneration is performed, the oil is sent to the power generation type high pressure accumulator 23 at a stretch, so that the pressure in the oil chamber OR rapidly rises and the piston 14b slides toward the gas chamber GR, and the gas chamber The GR is adiabatically compressed.

  When the gas chamber GR is adiabatically compressed, the temperature of the gas chamber GR rises from normal temperature (normal temperature) at a stretch, and the temperature of the power generation high-pressure accumulator 23 also rises accordingly. Since the thermoelectric elements 25a and 25b are installed in the peripheral part of the gas chamber GR with one of the operation surfaces facing the gas chamber GR, the thermoelectric elements 25a and 25b are caused by a temperature difference with the other operation surface. Electric power is generated.

  Therefore, since the thermal energy lost by heat radiation can be recovered by the thermoelectric elements 25a and 25b, the energy recovery efficiency can be improved.

  The electromotive force generated in the thermoelectric elements 25a and 25b is output from the power generation type high-pressure accumulator 23, adjusted by the current adjustment circuit 21, and then transmitted to the battery 22 and the ACC.

  Although the temperature change of the thermoelectric elements 25a and 25b is large, since the maximum power point tracking control is performed by the current adjustment circuit 21, energy loss during power generation can be effectively suppressed.

  When the vehicle speed is suddenly accelerated and powering is performed, the oil flows out from the power generation high-pressure accumulator 23 at a stretch, so that the pressure in the oil chamber OR decreases suddenly, and the piston 14b slides toward the oil chamber OR, and the gas The chamber GR is adiabatically expanded.

  When the gas chamber GR is adiabatically expanded, the temperature of the gas chamber GR is reduced from room temperature all at once, and accordingly, the temperature of the power generation type high pressure accumulator 23 is also decreased, so that an electromotive force is generated in the thermoelectric elements 25a and 25b.

  At this time, since the temperature acting on the working surface of each thermoelectric element 25a, 25b is opposite to that during regeneration, the electromotive force generated in each thermoelectric element 25a, 25b as shown in FIG. The polarity is also reversed.

  In contrast, in this regenerative system ERS, the polarity switching circuit 20 switches the connection state between the pair of output wirings s1, s2 and the pair of relay wirings h1, h2, and the electromotive force output from the thermoelectric elements 25a, 25b. The polarity is controlled to be reversed between regeneration and power running.

  Thereby, as shown in FIG. 10B, the polarity of the electromotive force output to the current adjusting circuit 21 is always constant. Therefore, energy can be recovered using the temperature change generated in the power generation type high pressure accumulator 23 both during power running and during regeneration, so that energy recovery efficiency can be improved.

  In addition, the power generation type high pressure accumulator according to the present invention is not limited to the above-described embodiment, and includes other various configurations.

  For example, the thermoelectric element is not necessarily installed on the surface layer portion 23a and the end surface portion 23b. You may install only in the surface layer part 23a or only the end surface part 23b. In short, it is only necessary that a thermoelectric element is installed in a peripheral part of the gas chamber GR that causes a temperature change.

  As shown in FIG. 11, the thermoelectric element 25c may be installed not on the inside of the container 14a but on the outer peripheral portion of the gas chamber GR outside the container 14a. It is a heat insulating material that covers the periphery of the thermoelectric element 25c. In this case, there is an advantage that wiring can be easily performed and the structure is simplified.

  Moreover, you may perform electric power generation only at the time of any one of the time of regeneration or power running. In that case, since the polarity switching circuit 20 can be omitted, there is an advantage that the system can be simplified.

13 Oil pump motor 14 High pressure accumulator 14a Container 14b Piston 15 Low pressure reservoir 20 Polarity switching circuit 21 Current adjustment circuit 22 Battery (storage battery)
23 Power generation type high pressure accumulator (high pressure accumulator)
23a Surface layer part 23b End surface part 25a, 25b Thermoelectric element C Automobile ERS regeneration system OR Oil chamber GR Gas chamber

Claims (4)

A high-pressure accumulator for an automobile that is connected to an oil pump motor that functions as one of an oil pump and a hydraulic motor and stores oil and gas under pressure,
A container having pressure resistance;
A piston that is slidably disposed within the container, and that divides the interior of the container into an oil chamber and a gas chamber in a sliding direction;
With
In the oil chamber, oil whose storage amount changes according to the operation of the oil pump motor is stored, and in the gas chamber, a certain amount of gas is stored,
A high-pressure accumulator in which a thermoelectric element that generates power using a temperature difference is installed in a peripheral portion of the gas chamber. The high pressure accumulator according to claim 1,
A high-pressure accumulator in which the thermoelectric element is installed on at least one of a surface layer portion of the piston facing the gas chamber and an end surface portion of the gas chamber facing the surface layer portion. An automobile regeneration system,
A high-pressure accumulator according to claim 1 or 2, and
A storage battery electrically connected to the thermoelectric element;
A polarity switching circuit electrically interposed between the thermoelectric element and the storage battery;
With
When the oil pump motor functions as an oil pump, when the oil flows into the high pressure accumulator, and when the oil pump motor functions as a hydraulic motor, when the oil flows out of the high pressure accumulator In the regenerative system, the polarity switching circuit reverses the polarity of the electromotive force output from the thermoelectric element to the storage battery. In the regeneration system according to claim 3,
A current adjustment circuit is further interposed downstream of the polarity switching circuit,
A regeneration system in which maximum power point tracking control is performed by the current adjustment circuit.

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