JP5370505B2 - Power supply control device and power management method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately estimate power to be generated and improve fuel economy for power generation while coping with power demand. <P>SOLUTION: Maximum supply power and power cost of a waste heat power generation system 5 and maximum supply power and power cost of other power supply sources are respectively calculated. Allocation of power to be requested to each power supply source is determined so that each power supply source can supply power in a range up to its maximum supply of power while giving priority to power supply sources with lower power cost for the power demand. Each power supply source supplies the determined requested power. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a power supply control device including a thermal generator that uses an engine or the like as a heat source and generates heat using the heat energy of the heat source, and a power management method thereof.

  Conventionally, a vehicular thermoelectric generator that generates electric power using thermal energy of exhaust gas discharged from an engine has been proposed (see, for example, Patent Document 1). According to the vehicular thermoelectric generator disclosed in Patent Document 1, the thermoelectric conversion element is wound around the exhaust passage of the combustion gas of the internal combustion engine, and the thermal energy transmitted to the thermoelectric conversion element is converted into electric energy.

JP 7-12009 A

  In addition to the device that generates power using the thermal energy of the exhaust gas described in Patent Document 1, for example, there is a thermoelectric generator that uses a Rankine cycle of refrigerant condensation and expansion. In this method, the refrigerant is expanded by the heat energy of the engine coolant, and the kinetic energy generated by the expansion is changed to rotational energy by the expander to drive the generator to generate power. In this way, if the power of the vehicle is covered by using the heat energy of the engine that has been almost discarded in the past, not only will the supply power shortage be resolved, but power generation using the driving force of the engine until now ( This saves fuel spent on engine power generation and improves fuel economy.

  However, such a thermoelectric generator system using a thermoelectric generator does not always generate constant electric power. For example, immediately after the engine is started, the generated power is small because the coolant temperature is low, and conversely, in the high-speed running state, the generated power is large because the coolant temperature is high. Therefore, even if thermoelectric power generation covers the power demand of the vehicle, in practice, combined use with engine power generation is indispensable, and how the generated power is shared between thermoelectric power generation and engine power generation can improve fuel efficiency. The problem is whether it can be improved.

  Further, when determining the sharing (distribution) of the generated power, the power generated by the thermoelectric power generation system must be accurately predicted in order to determine the distribution that leads to improved fuel efficiency. Here, in order to predict the generated power in the thermoelectric generation system, it is necessary to calculate the mechanical energy for driving the expander and the thermal generator from the internal energy of the refrigerant Rankine cycle. For that purpose, the vehicle speed, the outside temperature, the cooling water temperature are calculated. The balance calculation of Rankine cycle is performed using the above as input conditions.

  However, due to factors such as errors in the above input conditions, loss in parts that are difficult to predict, such as cooling water piping, and changes over time in the characteristics of various devices, the predicted generated power and the power that can actually be generated An error occurs between As a result, when the predicted generated power is smaller than the actual maximum generated power, the heat energy cannot be effectively used, and the effect of improving the fuel consumption is reduced. On the other hand, if the predicted generated power is larger than the actual maximum generated power, an excessive load is applied to the expander, and the Rankine cycle cannot be maintained. As a result, the rotational fluctuation of the expander gradually increases, and finally there is a problem that power generation becomes impossible due to step-out or stoppage.

  In addition, since the thermoelectric generation system includes auxiliary devices that consume electric power, such as a refrigerant pump, a water pump, and a cooling fan, it is necessary to subtract the electric power consumed by the auxiliary device from the generated electric power. However, since the cooling fan and the like are shared with other systems, the net amount of generated power can be obtained as a thermoelectric power generation system by simply subtracting the power consumed by such auxiliary equipment from the generated power. I ca n’t figure out exactly. In addition, since it is assumed that the generated power is lower than the power consumption of the auxiliary machine, handling of the generated power in that case is also a problem.

The present invention has been made in view of the above problems, the generated power to predict accurately, while responding power generation can Ru power control device to improve the fuel consumption at the time of the power demand, and power management It aims to provide a method.

The power supply control device according to claim 1 is a power supply control device including a plurality of power supply sources including a thermal generator that generates power using thermal energy of a heat source,
Temperature detection means for detecting the temperature of the heat source or the heat transfer medium of the heat source;
Calculating the maximum supply power that can be supplied by the thermal generator based on the temperature and the power cost, and calculating the maximum supply power and power cost of other power supply sources;
A distribution determining means for determining the distribution of required power to each power supply source so that power is supplied within the range of maximum supply power with priority given to power supply sources with low power costs with respect to demand power Each power supply source supplies required power.

  For example, when the vehicle power demand is higher than the maximum supply power that can be supplied by the power generation of the thermal generator, it is necessary to cover the power in cooperation with other power supply sources such as engine power generation. On the other hand, when the demand for power is small relative to the maximum power supply of the thermal generator, it is possible to cover the power only by thermal power generation, but unnecessary power generation not only produces surplus power without a place to go, but also the cooling water of the engine. When using a thermal generator that generates heat using thermal energy, the cooling water temperature of the engine may be excessively lowered, which may lead to deterioration of fuel consumption and emission.

  Therefore, for example, in order to improve fuel efficiency by using an engine as a heat source and generating power using the heat energy of the heat source, the appropriate power to be generated is determined from the maximum power supply and demand power of the thermal generator. In addition to controlling the thermal generator, a mechanism for appropriately determining the required power for other power supply sources such as engine power generation is required.

  Therefore, in the present invention, as described above, the maximum supply power of the thermal generator and the power cost are calculated based on the temperature of the heat source or the heat transfer medium of the heat source, and the maximum supply power of the other power supply sources, and Calculate the power cost, determine the distribution of the required power to each power supply source so that power is supplied within the range of the maximum power supply with priority from the power supply source with low power cost to the demand power, Each power supply source supplies this required power.

  As a result, electric power is covered by thermoelectric power generation that is basically free of power costs (zero), and thus power costs can be reduced. As a result, it is possible to improve fuel efficiency during power generation while meeting power demand.

The power supply control device according to claim 2 is a power supply control device including a plurality of power supply sources including a thermal generator that generates power using thermal energy of a heat source,
Temperature detection means for detecting the temperature of the heat source or the heat transfer medium of the heat source;
Calculating the maximum supply power that can be supplied by the thermal generator based on the temperature and the power cost, and calculating the maximum supply power and power cost of other power supply sources;
Distribution determining means for determining the distribution of the required power to each power supply source so that the total power cost of the total power cost of each power supply source is minimized, and each power supply source has the required power It is characterized by supplying.

  In this way, the allocation of the required power to each power supply source is determined so that the total power cost is minimized, and each power supply source generates power according to the distribution of the required power to meet the power demand. However, the power cost can be minimized.

  According to the power supply control device of the third aspect, the calculating means calculates the increment of the fuel consumption amount of the heat source at the time of power generation by the thermal generator with respect to the unit generated power of the thermal generator as the power cost of the thermal generator. And Thereby, the increment of the fuel consumption of the heat source by thermoelectric generation can be made into the electric power cost of a thermoelectric generator.

  According to the power supply control device of the fourth aspect, the thermoelectric generator uses engine cooling water as the heat transfer medium of the heat source, expands the refrigerant with the heat energy of the cooling water, and generates electric power using the operating energy. It is characterized by being. Thereby, the electric power generation using the thermal energy of the cooling water used for cooling the engine becomes possible.

  According to the power supply control device of the fifth aspect, the calculating means calculates the maximum power supply of the thermal generator from the pressure before expansion of the refrigerant, the flow rate of the refrigerant, and the coolant temperature. Thereby, in the thermoelectric generator using the refrigerant condensation and expansion cycle, the maximum supply power of the thermoelectric generator can be calculated from the pressure before the refrigerant expansion, the flow rate of the refrigerant, and the coolant temperature that can be used for the refrigerant expansion. it can.

According to the power supply control device of the sixth aspect, the calculating means includes
If the cooling water temperature falls below the lower limit value of the cooling water temperature control, the maximum power supply of the thermal generator is calculated as zero,
When the coolant temperature exceeds the lower limit value of the coolant temperature control, power that is approximately proportional to the difference between the coolant temperature and the lower limit value is calculated as the maximum supply power of the thermoelectric generator.

  Thus, when the coolant temperature falls below the lower limit value, the maximum power supply of the thermal generator can be set to zero so that no power can be supplied from the thermal generator. Can be prevented from excessively decreasing. As a result, deterioration of fuel consumption and emission can be prevented. Moreover, since the maximum supply power of the thermal generator is approximately proportional to the rise in the coolant temperature, the maximum supply power can be calculated based on the coolant temperature.

The power supply control device according to claim 7,
A power shortage detection means for detecting power shortage in a power supply system that receives power supply from a plurality of power supply sources;
When the power shortage detecting means detects the power shortage, the power supply power restriction reducing means for relaxing the restriction on the power supply of the thermal generator caused by falling below the lower limit value of the water temperature control is provided.

  As a result, in an emergency such as a shortage of power, priority can be given to avoiding a battery run-up or a bus voltage drop due to power shortage rather than a deterioration in fuel consumption or emissions.

  As described in claims 8 and 9, the power shortage detecting means detects power shortage when the required power exceeds the supplied power or the bus voltage of the power supply system falls below a predetermined lower limit voltage. can do.

  According to the power supply control device of the tenth aspect, the supply power restriction alleviating means lowers the lower limit value of the coolant temperature control. Thereby, the restriction | limiting of the power supply of a thermal generator can be eased. In addition, as described in claim 11, a new restriction of power supply is calculated based on a function map in which the maximum power supply of the thermal power generator is separately determined or a change in the internal energy of the heat transfer medium, thereby relaxing the restriction. You may make it plan.

  According to the power supply control device of claim 12, the calculating means is the maximum supply that can be supplied by the thermal energy of the cooling water that exceeds the target water temperature of the cooling water temperature control as the maximum supply power and power cost of the thermal generator. The power and the power cost are calculated.

  Heat energy exceeding the target water temperature of the cooling water becomes completely unnecessary heat energy. Therefore, by calculating the maximum supply power that can be supplied using this completely unnecessary thermal energy and the power cost, the maximum supply power that can be supplied without incurring power costs and causing deterioration in fuel consumption and emissions. It can be.

The power supply control device according to claim 13 includes water temperature increase control means for performing water temperature increase control for increasing the coolant temperature.
The calculation means is characterized in that the additional fuel consumption of the heat source necessary for the water temperature increase control with respect to the electric power that can be supplied by the water temperature increase control is added to the power cost of the thermoelectric generator.

  For example, when there is more electric power demand than the maximum supply power, there is a case where the temperature of the cooling water is raised higher than usual, and the thermal power is generated by the thermal generator using the heat energy of the rise. In such a case, for example, as disclosed in JP-A-9-88564, the coolant temperature of the engine can be increased by retarding the ignition timing of the engine.

  Therefore, in the present invention, when the water temperature increase control is executed, the engine shaft output is kept within a predetermined range (the engine output decreases at the ignition delay angle, so this compensation is necessary), and the electric power that can be supplied by the water temperature increase control is controlled. Then, the additional fuel consumption of the engine required for the water temperature rise control is obtained, and this is added to the power cost. Thereby, when performing water temperature rise control, it can be reflected on electric power cost.

According to the power supply control device according to claim 14, the plurality of power supply sources include a plurality of capacitors,
At least one of the plurality of capacitors is connected to the thermoelectric generator via the first power supply bus so as to store the electric power generated by the thermoelectric generator,
The other battery is connected to a second power bus different from the first power bus,
Power supply bus connection means for connecting the first power supply bus and the second power supply bus;
Power transfer between the first power bus and the second power bus is performed by the power bus connecting means. Thereby, two power supply buses can be managed and operated flexibly.

  According to the power control device of the fifteenth aspect, the first power bus is a power power bus of the hybrid electric vehicle, and the electric power of the thermal generator is used for traveling of the hybrid electric vehicle via the power power bus. It is used as electric power. Thereby, the electric power generated by the thermal generator can be used as electric power for running the hybrid electric vehicle.

  Since the power management method of the power supply control device according to the sixteenth to thirty-third embodiments is the same as the operation effect of the power supply control device according to the first to fifteenth embodiments, the description thereof is omitted.

It is a block diagram which shows the electric system of the vehicle in embodiment of this invention. It is a lineblock diagram of waste heat power generation system 5 concerning a 1st embodiment. It is a flowchart which shows the calculation process which calculates the maximum supply electric power and electric power cost by the waste heat generator 5c. It is a flowchart which shows the first half part of the distribution determination process which determines the distribution of the request | requirement electric power to each power supply source performed in the vehicle power supply control means 13. It is a flowchart which shows the second half part of the distribution determination process which determines the distribution of the request | requirement electric power to each power supply source performed in the vehicle power supply control means. It is a graph which shows the relationship between the maximum supply electric power of the waste heat generator 5c, a refrigerant | coolant pressure, a refrigerant | coolant flow volume, and engine cooling water temperature. It is a graph which shows the relationship between the electric power cost of the waste heat generator 5c, and engine cooling water temperature. It is a block diagram which shows the electric system of the vehicle in the modification 1 of 1st Embodiment. It is a flowchart which shows the allocation determination process which determines allocation of the request | requirement electric power to two electric power supply sources in the modification 1 of 1st Embodiment. It is a figure for demonstrating the electric power management method of the electric system of the vehicle in the modification 2 of 1st Embodiment. It is a figure for demonstrating the relationship between the electric power cost of thermoelectric power generation at the time of performing water temperature rise control (waste heat increase control), and engine cooling water temperature. (A) is a figure which shows the case where the maximum supply power is increased by lowering the lower limit value ( _{Tw_LL} ) to ( _{Tw_LL} ′), and (b) is a separately determined map, Rankine cycle balance calculation, etc. It is a figure which shows the case where a water temperature restriction _| limiting ( _{WTG_MAX} ) is calculated. It is a block diagram which shows the electric system of the vehicle in the modification 4 of 1st Embodiment. It is a block diagram which shows the electric system of the vehicle in the modification 5 of 1st Embodiment. It is a block diagram which shows the electric system of the hybrid electric vehicle (HV) in the modification 6 of 1st Embodiment. It is a block diagram at the time of simplifying the structure of the electric system of a hybrid electric vehicle (HV) in the modification 6 of 1st Embodiment. It is a block diagram of the waste heat power generation system 5 concerning 2nd Embodiment. Calculation procedure of maximum supply power (W _{TG — MAX} ), power cost (C _TG ), and load power (L _TG ) in the waste heat generator 5 c according to the second embodiment, and a control procedure of the generated power by the waste heat generator 5 c It is a flowchart which shows. Is a flowchart showing details of calculation procedure of the maximum supply power _{(W TG_MAX)} and power cost _{(C TG)} in the waste heat generator 5c. It is a Mollier diagram of a refrigerant (HFC-134a). It is a flowchart which shows the procedure which determines the operating point of Rankine cycle. (A) is a right triangle CDR having a hypothetical side of the refrigerant state stroke C → D on the Mollier diagram in the prediction cycle, and (b) is a refrigerant state stroke C ′ → on the Mollier diagram in the actual machine cycle. It is a right triangle C′D′R ′ with D ′ as the hypotenuse. It is a flowchart which shows the flow of the calculation procedure of the power consumption (Wcp) in the waste heat power generation system.

  Hereinafter, embodiments of a thermoelectric generator, a power supply controller, and a power management method thereof according to the present invention will be described with reference to the drawings. In this embodiment, an explanation will be given of an application example of a power control device in an electric system including a thermoelectric generator mounted on an automobile, and its power management method, but not limited to automobiles, railway vehicles, ships, The present invention can also be applied to a moving body having a heat source such as an aircraft.

(First embodiment)
FIG. 1 is a block diagram showing an electric system of a vehicle in the present embodiment. The electric system of the vehicle shown in the figure includes an engine 1, an engine control means 2, an alternator 3, an alternator control means 4, a waste heat power generation system 5, a waste heat power generation control means 6, a water temperature detection means 7, a battery 8, and a battery state detection. A means 9, a bus voltage detection means 10, a current detection means 11, a load control means 12, and a vehicle power supply control means 13 are configured.

  The engine 1 is an internal combustion engine that uses gasoline, light oil, or the like as fuel, and is connected to an alternator 3 by a belt. The alternator 3 and the waste heat power generation system 5 are connected to the battery 8 and the load control means 12 through a power bus. The load control means 12 performs power feeding control of the loads 1 to n, and includes an operation switch (not shown) necessary for performing the power feeding control and various sensors (not shown) for the power feeding control. Therefore, output control or intermittent operation of the load belonging to itself is performed according to the external input signal and the output of these sensors.

  The engine control means 2 is a control device for controlling the engine 1 and is connected to the vehicle power supply control means 13. The engine control means 2 transmits various information such as the engine speed detected by a sensor (not shown) for detecting various states of the engine 1 to the vehicle power supply control means 13 and from the vehicle power supply control means 13. The output of the engine 1 is controlled according to the command.

  The alternator control means 4 transmits information such as the current generated power and the rotation speed of the alternator 3 to the vehicle power supply control means 13. The alternator control means 4 receives vehicle braking information input from a vehicle controller (not shown), and controls the generated power of the alternator 3 to a value corresponding to the vehicle braking amount recognized by the vehicle braking information. It is also possible to increase the magnetic current and perform regenerative braking to generate a necessary vehicle braking amount (regenerative braking amount).

  The vehicle controller calculates a vehicle braking amount corresponding to an operation amount of a braking operation means such as a brake depression amount sensor (not shown) and generates a braking amount obtained by subtracting the regenerative braking amount from the vehicle braking amount. This is a command to the control unit of the hydraulic brake device that does not.

  Further, the alternator control means 4 determines the increase amount of the generated power in the regenerative braking within the range of the maximum power (maximum supply power value) that can be generated (supplied) by the alternator 3 and the maximum charge of the battery 8. Set within the range of possible power value (maximum charging power value). That is, the alternator control means 4 controls the power generation of the alternator 3, controls the charge / discharge of the battery 8, and controls the power consumption of each electric load.

  The vehicle power supply control means 13 includes a battery state detection means 9 for detecting the state of the battery 8 such as battery temperature, battery input / output current, and battery voltage, a bus voltage detection means 10 for detecting the voltage level of the power supply bus, and load control. The current detection means 11 for detecting the load current to the means 12 is connected. The vehicle power supply control means 13 is connected to the load control means 12 through a multiplex signal transmission line, and exchanges information bi-directionally with the load control means 12 through multiplex communication.

  The vehicle power supply control means 13 monitors the state of the alternator 3, the waste heat power generation system 5, the battery 8, the power bus, etc., and the alternator 3 and the waste heat power generation system 5 through the alternator control means 4 and the waste heat power generation control means 6. To control. The power generated by the alternator 3 and the waste heat power generation system 5 is controlled by a command from the vehicle power supply control means 13.

  FIG. 2 shows a configuration of the waste heat power generation system 5. The waste heat power generation system 5 performs thermoelectric generation using a refrigerant condensation and expansion cycle. That is, the heat energy of the engine cooling water is absorbed into the refrigerant by the heat exchanger 5a, and this refrigerant expands with the heat energy of the engine cooling water in the expander 5b, and drives the waste heat generator 5c with the kinetic energy. Generate electricity. Thereby, the electric power generation using the thermal energy of engine cooling water becomes possible.

  The refrigerant pump 5e is a pump for circulating the refrigerant in the expander 5b and the condenser. The refrigerant pump 5e transmits the refrigerant pump rotation speed (Np) to the refrigerant pump motor control means 5g, and is controlled by the refrigerant pump motor control means 5g. The The refrigerant pump motor control means 5 g transmits the refrigerant pump rotation speed (Np) to the waste heat power generation control means 6.

  The pressure sensor 5 f detects the refrigerant pressure (Ph) at the inlet of the refrigerant pump 5 e and transmits it to the waste heat power generation control means 6. The water temperature detection means 7 detects the engine cooling water temperature (Tw) and transmits it to the waste heat power generation control means 6.

  The waste heat power generation control means 6 transmits a generated power command to the generator control means 5d, and the generator control means 5d receives the generated power command and controls the waste heat power generator 5c to generate power from the waste heat power generator 5c. Supply generated power to the power bus. The waste heat power generation control means 6 transmits a water pump rotation command to the water pump motor control means 5h, and the water pump motor control means 5h receives the water pump rotation command and controls the electric water pump.

  Next, the electric power management of the electric system shown in FIG. In this power management, the maximum power supply and power cost in a plurality of power supply sources (in this embodiment, the engine 1, the regenerative braking device, the battery 8, another power source not shown, and the waste heat generator 5c) are calculated. Then, the distribution of the required power to each power supply source is determined so that power is supplied within the range of the maximum supply power with priority from the power supply source having a low power cost to the demand power of the electric system. The determined required power is transmitted to each power supply source, and each power supply source supplies this required power. The regenerative braking device as the power supply source includes an alternator 3 at the time of regenerative braking and an alternator control means 4 for controlling it.

  Here, the calculation method of the maximum generated power and the power cost in the engine 1, the regenerative braking device, the battery 8, and another power source as the power supply source, and the calculation method of the demand power are disclosed in Japanese Patent Application Laid-Open No. 2004-260908 by the present applicant. Since the calculation method in the vehicle electrical system management method disclosed in Japanese Patent Publication No. Gazette may be adopted, the description thereof is omitted. In the present embodiment, calculation processing for calculating the maximum supply power and power cost by the waste heat generator 5c, which is executed in the waste heat power generation control means 6, will be described with reference to the flowchart shown in FIG.

  First, in step (hereinafter referred to as S) 10, the refrigerant pressure (Ph) at the inlet of the refrigerant pump 5e from the pressure sensor 5f, the refrigerant pump rotation speed (Np) from the electric motor of the refrigerant pump 5e, and the engine cooling from the water temperature detecting means 7 Collect each data of water temperature (Tw).

In S20, the refrigerant mass flow rate (Gr) is obtained by multiplying the refrigerant pump rotation speed (Np) by the discharge volume (Vp), the refrigerant density (ρ), and the refrigerant pump efficiency (ηp). The maximum supply power (W _{TG — MAX} ) in the waste heat generator 5c is _estimated from the refrigerant pressure (Ph), the refrigerant mass flow rate (Gr), and the engine coolant temperature (Tw).

For example, as shown in FIG. 6, a map with each variable of the refrigerant pressure (Ph), the mass flow rate (Gr) of the refrigerant, and the engine coolant temperature (Tw) is prepared in advance, and the maximum power generation from this map is possible. The supplied power (W _{TG_MAX} ) is obtained. Thus, in thermoelectric generation using the refrigerant condensation and expansion cycle, the maximum power supply for thermoelectric generation is calculated from the pressure before refrigerant expansion, the mass flow rate of the refrigerant, and the coolant temperature that can be used for refrigerant expansion. can do.

As can be seen from the relationship between the engine cooling water temperature (Tw) and the maximum supply power (W _{TG_MAX} ) in the _figure , the maximum supply power (W _{TG_MAX} ) is the lower limit value of the water temperature control for the engine cooling water temperature (Tw). if the control limit _{(Tw _LL),} theoretically, the power is substantially proportional to the difference between the engine coolant temperature (Tw) and the water temperature control limit _{(Tw _LL).} Therefore, it may be calculated by the following equation. The variables in the following equation are as shown in FIG.

(Equation 1)
Maximum power supply (W _{TG_MAX} ) = k × ηTG × (Tw− _{Tw_LL} )
Thereby, the maximum supply power can be calculated based on the water temperature of the engine cooling water. When the engine coolant temperature (Tw) is lower than the water temperature control lower limit ( _{Tw_LL} ), the maximum power supply (W _{TG_MAX} ) may be zero. Thereby, since it can be considered that there is no power supply from the waste heat generator 5c, it is possible to prevent the engine cooling water temperature from being excessively lowered by thermoelectric power generation. As a result, deterioration of fuel consumption and emission can be prevented.

In S30, the power cost (C _TG ) in the waste heat generator 5c is calculated. This power cost (CTG) is calculated by the following equation. Note that the variables in the following equation are as shown in FIG.

(Equation 2)
Power cost (C _TG ) = [{k _F (Tw−a × W _TG ) −k _F (Tw)} × F (ω, τ)] / W _TG
As shown in the above formula, the power cost (C _TG ) is increased from the consumption amount based on the fuel consumption amount of the engine 1 at the control target (center) temperature ( _{Tw_M} ) of the temperature control of the engine coolant temperature (Tw). Calculate from minutes. That is, the fuel consumption when the engine coolant temperature (Tw) is the control target temperature ( _{Tw_M} ) is F (ω, τ), and the fuel at the engine coolant temperature (Tw) at the same rotational speed and output torque. When the ratio to the consumption is k _F (Tw), the rate of change in temperature is proportional to the generated power (W _TG ), so the increase in fuel consumption can be obtained from the numerator of the above equation. Therefore, the power cost (C _TG ) can be obtained by dividing the increment of the fuel consumption by the generated power (W _TG ).

Thereby, the increment of the fuel consumption of the engine 1 with respect to the unit generated electric power of the waste heat generator 5c can be made into the electric power cost ( _CTG ) of the waste heat generator 5c. In S _<b> 40, the calculated maximum supply power (W _{TG_MAX} ) and power cost (C _TG ) are transmitted to the vehicle power supply control means 13.

The maximum supply power _{(W TG_MAX)} in the S20 and S30, and in the calculation of the power cost _{(C TG),} the thermal energy of the engine cooling water exceeds the control target temperature of the water temperature control of the engine cooling water _{(Tw _M)} The maximum supply power that can be generated and supplied and the power cost may be calculated.

That is, the heat energy exceeding the control target temperature ( _{Tw_M} ) of the engine coolant becomes completely unnecessary heat energy. Therefore, by calculating the maximum supply power that can be supplied using this completely unnecessary thermal energy and the power cost, the maximum supply power that can be supplied without incurring power costs and causing deterioration in fuel consumption and emissions. It can be.

In S50, the required power (W _{TG_rq} ) is received from the vehicle power supply control means 13, and in S60, the rotational speed of the waste heat generator is set so that the actual generated power (W _TG ) is equal to the required power (W _{TG_rq} ). Control torque.

Subsequently, a distribution determination process for determining the distribution of the required power to each power supply source executed in the vehicle power supply control means 13 will be described with reference to the flowcharts shown in FIGS. First, in S110 shown in FIG. 4, the power demand (W _D ) of the entire electric system of the vehicle is calculated, and in S120, information on the maximum supply power (W _{XX_MAX} ) and power cost (C _XX ) from each power supply source. collect.

In S130, the power supply source (AA) with the lowest power cost is extracted from the collected information. In S140, first, the maximum supply power (W) of the power supply source (AA) is selected for the power demand (W _D ). _{AA_MAX} ). Therefore, when the power cost of the waste heat generator 5c is 0, power is preferentially supplied from the waste heat generator 5c to the loads 1 to n.

In S150, it is determined whether or not the power demand (W _D ) can be covered by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA). Here, when an affirmative determination is made, i.e., when the power demand (W _D ) can be covered by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA), the _{process proceeds} to S180 and a negative determination is made. In the case, that is, when the power demand (W _D ) cannot be covered only by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA), the process proceeds to S160.

In S180, the required supply power (W _{AA_rq} = W _D ) to the power supply source (AA) is determined, and the determined required power (W _{AA_rq} ) is transmitted to the power supply source (AA). As a result, the power supply source (AA) supplies power so that the actual generated power (WAA) becomes equal to the required power ( _{WAA_rq} ).

On the other hand, in S160, it determines the power supply required power to _{(AA) (W AA_rq = W} AA_MAX), and transmits the determined required power _{(W AA_rq)} power supply to the (AA). As a result, the power supply source (AA) supplies power so that the actual generated power (WAA) becomes equal to the required power ( _{WAA_rq} ).

In S170, the required power (W _D1 ) for the shortage that cannot be covered by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA) is _obtained by the following equation.

(Equation 3)
Insufficient power demand (W _D1 ) = power demand (W _D ) _−maximum supply power (W _{AA_MAX} )
In S190 shown in FIG. 5, the power supply source (BB) with the lowest power cost is extracted next to the power supply source (AA). In S200, the power supply source (W _D1 ) is supplied to the shortage of required power (W _D1 ). BB) maximum supply power (W _{BB_MAX} ) is allocated.

In S210, it determines whether it is possible to cover the shortage of the required power _{(W D1)} at the maximum supply power of the power source _{(BB) (W BB_MAX).} If the determination is affirmative, the process proceeds to S250. If the determination is negative, the process proceeds to S220.

In S250, the required power (W _{BB_rq} = W _D1 ) for the power supply source (BB) is determined, and the determined required power (W _{BB_rq} ) is transmitted to the power supply source (BB). As a result, the power supply source (BB) supplies power so that the actual generated power (W _BB ) is equal to the required power (W _{BB — rq} ).

On the other hand, in S220, the required power (W _{BB_rq} = W _{BB_MAX} ) for the power supply source (BB) is determined, and the determined required power (W _{BB_rq} ) is transmitted to the power supply source (BB). As a result, the power supply source (BB) supplies power so that the actual generated power (W _BB ) is equal to the required power (W _{BB — rq} ).

In S230, the required power (W _D2 ) for the shortage that cannot be covered by the maximum supply power (W BB — MAX) of the power supply source (BB) is _obtained by the following equation.

(Equation 4)
Insufficient power demand (W _D2 ) = power demand (W _D1 ) _−maximum supply power (W _BB — _MAX )
In S240, the power supply source (CC) with the lowest power cost is extracted next to the power supply source (BB), and thereafter the power supply source (CC) is sequentially installed so that the required power (W _D2 ) for the shortage is covered. , S200 to S250 are repeatedly executed.

In S300, the maximum supply power (WEE_MAX) <the required power (W _D4 ) for the power supply source (EE) having the highest power cost (in this embodiment, five power supply sources). In this case, control is performed so as to suppress the power supply of the load with low priority so that the maximum supply power (WEE_MAX) ≧ the required power for the shortage (W _D4 ).

  Thus, in the electric system of the vehicle of the present embodiment, the maximum supply power and power cost of the waste heat generator 5c are calculated, the maximum supply power and power cost of other power supply sources are calculated, and the demand power Therefore, the allocation of the required power to each power supply source is determined so that power is supplied within the range of the maximum supply power in preference to the power supply source having a low power cost. Supply the required power.

  As a result, electric power is covered by thermoelectric power generation that is basically free of power costs (zero), and thus power costs can be reduced. Thereby, the fuel consumption at the time of electric power generation can be improved, responding to electric power demand.

(Modification 1)
FIG. 8 is a block diagram showing the electric system of the vehicle in this modification. The vehicle electrical system shown in the figure is obtained by adding a waste heat power generation system 5, a waste heat power generation control means 6, and a water temperature detection means 7 to a conventional vehicle electrical system.

  In this embodiment, in addition to calculating the maximum supply power and power cost of the waste heat generator in the waste heat power generation system 5 by the waste heat power generation control means 6, the power cost when the same power is generated by the alternator 3 is Calculation is made based on the rotation speed, torque, and fuel consumption rate of the engine 1 from the engine control means 2, and is compared with the power cost of the waste heat generator.

  When the power cost of the waste heat generator is low, the waste heat generator generates power and keeps the bus voltage of the power bus at a predetermined value or higher. As a result, power generation in the alternator 3 is automatically suppressed, so that the waste heat generator preferentially covers the required power. If the power cost of the waste heat generator is high because the cooling water temperature is low, etc., or if the maximum power supply is not sufficient for the demand of the load, the bus voltage will decrease, so the alternator By turning on a regulator (not shown) 3 and supplying power generated by engine power generation, the bus voltage is maintained at a predetermined value or more.

  Next, a flowchart shown in FIG. 9 is shown for the distribution determination process for determining the distribution of the required power to the two power supply sources (waste heat generator and alternator 3), which is executed in the heat generation control means 6 in this modification. It explains using.

First, in S310 shown in FIG. 9, the power demand (W _D ) of the entire electric system of the vehicle is calculated, and in S320, information on the maximum supply power (W _{XX_MAX} ) and power cost (C _XX ) from two power supply sources. To collect.

In S330, the power supply source (AA) with the lower power cost is extracted from the collected information, and in S340, the maximum supply power ( _{WAA_MAX} ) of the power supply source (AA) with respect to the power demand (W _D ). ).

In S350, it is determined whether or not the power demand (W _D ) can be covered by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA). If the determination is affirmative, the process proceeds to S390. If the determination is negative, the process proceeds to S360.

In S390, the required power (W _{AA_rq} = W _D ) for the power supply source (AA) is determined, and the determined required power (W _{AA_rq} ) is transmitted to the power supply source (AA). As a result, the power supply source (AA) supplies power so that the actual generated power (WAA) becomes equal to the required power ( _{WAA_rq} ).

On the other hand, in S360, it determines the power supply required power to _{(AA) (W AA_rq = W} AA_MAX), and transmits the determined required power _{(W AA_rq)} power supply to the (AA). As a result, the power supply source (AA) supplies power so that the actual generated power (WAA) becomes equal to the required power ( _{WAA_rq} ).

In S370, the required power (W _D1 ) for the shortage that cannot be covered by the maximum supply power (W _{AA_MAX} ) of the power supply source (AA) is _obtained by the following equation.

(Equation 5)
Insufficient power demand (W _D1 ) = power demand (W _D ) _−maximum supply power (W _{AA_MAX} )
In S380, the required power (W _BB — _rq = W _D1 ) to the other power supply source (BB) is determined. The maximum supply power _{(W BB_MAX)} <when a shortage of the required power _{(W D1),} like the maximum supply power _{(W BB_MAX)} ≧ shortage of the required power _{(W D1),} priority Control to suppress the power supply of low load.

  Thereby, when the power supply source is limited to the waste heat generator and the conventional alternator 3, the power cost can be minimized with the above-described simple configuration.

(Modification 2)
The distribution determination process for determining the distribution of the required power to each power supply source, which is executed in the vehicle power supply control means 13 of the present embodiment, is the maximum supply with priority given to the demand power from the power supply source having a low power cost. The distribution of required power to each power supply source is determined so that power is supplied within the range of power, but the total power, which is the total power cost of each power supply source, as in this modification, is determined. You may determine distribution of the request | requirement electric power to each electric power supply source so that cost may become the minimum.

FIG. 10 is obtained by adding waste heat power generation as a supply source to the above-described vehicle power management method disclosed in Japanese Patent Laid-Open No. 2004-260908 by the present applicant. As shown in the figure, when waste heat power generation is added, the amount of power generation (maximum supply power: W _{TG_MAX} ) and power cost information (power cost: C _TG ) are output as with other power supply sources. Each power supply source generates power based on the distribution command determined so that the total power cost, which is the total power cost of each power supply source, is minimized. Thereby, in each electric power supply source, it can suppress electric power cost to the minimum, respond | corresponding to electric power demand by generating according to distribution of request | requirement electric power.

(Modification 3)
The thermoelectric power generation of this embodiment is usually one that generates power using waste heat that has been completely discarded, but when the electric power of the vehicle's electrical system is insufficient (that is, there is more power demand than the maximum supply power). In some cases, the temperature of the engine cooling water is raised from the normal temperature, and it is desired to generate electric power by the thermal generator using the thermal energy of the rise. In such a case, for example, as disclosed in JP-A-9-88564, the engine coolant temperature can be raised by retarding the ignition timing of the engine.

  Therefore, in the present modification, when executing the water temperature increase control, the additional fuel consumption of the engine required for the water temperature increase control with respect to the electric power that can be supplied by the water temperature increase control while keeping the engine shaft output within a predetermined range. Is added to the power cost. Thereby, when performing water temperature rise control, it can be reflected on electric power cost.

Note that the relationship between the generated power (W _TG ) and the additional fuel consumption ( _{F_add} ) in this water temperature rise control (waste heat increase control) is made into a map (FIG. 11) or modeled in advance, and waste heat power generation By providing the control means 6, the maximum power supply (W _{TG_MAX} ) can be increased even when the engine coolant temperature (Tw) is low. Further, it is possible to cope with the case where it is desired to increase the thermoelectric power generation even using fuel, such as when the alternator supply is insufficient for the increase in the vehicle power load.

  Further, as described above, the water temperature increase control is performed not only when the electric power of the vehicle is short, that is, when the remaining capacity (SOC) of the battery 8 is significantly reduced, not only when the power demand is higher than the maximum supply power. At the same time, power generation restrictions due to a decrease in the coolant temperature may be relaxed (or canceled) to generate power, thereby avoiding device malfunctions and battery exhaustion due to a decrease in bus voltage.

That is, the water temperature limit {(W _TG — _MAX ) = k × ηTG × (Tw− _{Tw_LL} )} in the maximum generated power is relaxed, and the supplied power is increased as much as possible. Specifically, as shown in FIG. _12A , the maximum supply power is increased by lowering the lower limit value ( _{Tw_LL} ) to ( _{Tw_LL} ′), or separately set as shown in FIG. 12B. The water temperature limit (W _{TG_MAX} ) is calculated by a balance map or Rankine cycle balance calculation.

  As a result, in an emergency such as a shortage of power, priority can be given to avoiding a battery run-up or a bus voltage drop due to power shortage rather than a deterioration in fuel consumption or emissions. As for the relaxation (cancellation) control of the water temperature restriction, a command from the vehicle power supply control means 13 to the waste heat power generation control means 6, the waste heat power generation control means 6 falls below a predetermined lower limit voltage of the bus voltage, or It may be activated by detecting that the required power exceeds the supplied power.

(Modification 4)
FIG. 13 is a block diagram showing an electric system of the vehicle in this modification. In this modification, as shown in the figure, a battery 1 and a battery 2 are arranged in a power bus 1 connected to an alternator 3 and a power bus 2 connected to a waste heat power generation system 5, respectively. They are connected by different voltage bus connection means 14 such as a DC / DC converter.

  The battery 2 stores electric power whose electric power cost of the waste heat power generation system 5 is approximately 0 (zero), and supplies electric power to the power supply bus 1 through the different voltage bus connection means 14. In addition, this embodiment corresponds to idling stop of the vehicle, and by discharging the battery 2, power is supplied to the loads 1 to n at idling stop and to the starter at engine start.

  As a result, instead of the electric power that has conventionally been stored in the battery by engine power generation, the electric power can be accommodated at the time of idling stop by thermoelectric power generation, so that the fuel efficiency of the vehicle can be improved.

  In addition, since the power bus 2 also has a large voltage change, it is necessary to provide the different voltage bus connection means 14 so as not to transmit the influence to the power bus 1. As a result, the two power buses can be flexibly managed and operated, so that it is possible to construct a power system that is resistant to failure and flexibly cope with the addition of a new power supply source. Since the battery 2 has a large change in SOC, it is desirable to use a nickel metal hydride battery or a lithium ion battery that is less likely to deteriorate than a lead battery.

(Modification 5)
FIG. 14 is a block diagram showing an electric system of the vehicle in this modification. In this modification, the configuration of the modification 1 shown in FIG. 8 is divided into a power bus 1 and a power bus 2, and a different voltage bus connection means 14, a battery 2, and an idle stop starter are added.

  Basically, the operation is the same as that of the first modification, but the presence of the battery 2 enables a more flexible operation for reducing the power cost. For example, when the engine cooling water temperature is low during idle stop and the power cost is generated even by thermal power generation, it is possible to supply the power with the low power cost stored in the battery 2 in advance. In addition, when the engine cooling water temperature is high and the power cost of thermoelectric power generation is 0 (zero) during running, the total power cost can be reduced by generating surplus power in the battery 2 by generating more than the power demand of the vehicle. Can be lowered.

(Modification 6)
FIG. 15 is a block diagram showing an electric system in a hybrid electric vehicle (HV) in the present modification. In this modification, the battery 2 described in the modification 5 corresponds to a 12V battery, the battery 1 corresponds to an HV battery, and the different voltage bus connection means 14 corresponds to a DC / DC converter. Similar to Example 5.

  Thus, by connecting the power supply bus connected to the waste heat generator to the high power bus of the HV battery, the electric power generated by the thermoelectric generation can be used as electric power for traveling. In addition, a large-capacity HV battery can be utilized to enable more flexible power generation operation in accordance with the use situation and conditions of the vehicle, and the fuel efficiency of the hybrid electric vehicle (HV) can be further improved. FIG. 16 is a block diagram in the case where the configuration of the electrical system in FIG. 15 is simplified.

(Second Embodiment)
Since the second embodiment is often in common with that according to the first embodiment, a detailed description of the common parts will be omitted below, and different parts will be mainly described. In the first embodiment described above, when calculating the maximum supply power (W _{TG_MAX} ) by the waste heat generator 5c, as shown in FIG. 6, the refrigerant pressure (Ph), the refrigerant mass flow rate (Gr), and the engine A map with each variable of the coolant temperature (Tw) is prepared in advance, and the maximum supply power (W _{TG_MAX} ) that can be generated is obtained from this map.

On the other hand, in the present embodiment, when calculating the maximum supply power (W _{TG_MAX} ) by the waste heat generator 5c, the calculation is performed with the balance of the Rankine cycle of the refrigerant and the correction by the actual measurement of the refrigerant pressure. The supply power (W _{TG_MAX} ) is calculated.

  In FIG. 17, the structure of the waste heat power generation system 5 in this embodiment is shown. The waste heat power generation system 5 of the present embodiment includes pressure sensors 5i and 5j that detect a refrigerant pressure (Pex_in) at the inlet of the expander 5b and a refrigerant pressure (Pex_out) at the outlet. . As described above, by providing the pressure sensors 5i and 5j that actually detect the pressure during expansion or / and condensation of the refrigerant, it is possible to correct the predicted value of the generated power, which will be described later, by actual measurement. The detection signals of the pressure sensors 5 i and 5 j are output to the waste heat power generation control means 6.

  The cooling fan 5k shown in FIG. 17 is shared with other in-vehicle systems, and receives power supply from the load control means 12 via the cooling fan control means shown in FIG. The operation of the cooling fan 5k is controlled by the cooling fan control means. The cooling fan control means is controlled in response to a command from the waste heat power generation control means 6.

  Next, electric power management performed by the vehicle power supply control means 13 will be described. In this power management, the maximum power supply and power cost in a plurality of power supply sources (in this embodiment, the engine 1, the regenerative braking device, the battery 8, another power source not shown, and the waste heat generator 5c) are calculated. Then, as shown in FIG. 10, the distribution of the required power to each power supply source is determined so that the total power cost, which is the total power cost of each power supply source, is minimized.

  When determining the distribution, the power cost of each power supply source is compared, and if the power cost of the waste heat generator 5c is lower than other power supply sources, the maximum supplyable power by the waste heat generator 5c is calculated. The distribution of the required power to the waste heat generator 5c is determined so that the power generated by the waste heat generator 5c is preferentially supplied within the range. Thereby, it can be expected to determine the distribution of required power that leads to improved fuel efficiency.

  Moreover, when deciding the distribution, the priority of the power load of the waste heat generator 5c may be set higher than other power loads. Thereby, priority is given to the starting of thermoelectric generation, and thermoelectric generation can be realized. The waste heat generator 5c normally generates power preferentially because the power cost is zero (0). However, when the waste heat generator 5c is not started after a cold start or the like, power shortage occurs and power load control is performed. Even when necessary, it is possible to secure the operating power of auxiliary equipment for starting a thermal generator such as a refrigerant pump and an electric water pump, and to start the thermal power generation.

  Here, the calculation method of the maximum generated power and the power cost in the engine 1, the regenerative braking device, the battery 8, and other power sources as the power supply source, the calculation method of the demand power, and the determination method of the distribution of the required power are as follows. Since the calculation method in the management method of the electric system for vehicles disclosed in Japanese Patent Application Laid-Open No. 2004-260908 by the applicant may be adopted, the description thereof is omitted.

Hereinafter, a calculation procedure of the amount of power that can be generated by the waste heat generator 5c (maximum supply power: W _{TG — MAX} ), power cost information (power cost: C _TG ), and load power (L _TG ), which is executed in the waste heat power generation control unit 6 The control procedure of the generated power by the waste heat generator 5c will be described with reference to the flowchart shown in FIG.

First, in S10a, the maximum supply power (W _{TG_MAX} ) and power cost (C _TG ) of the waste heat generator 5c are calculated from the current vehicle state. Since the waste heat power generator 5c generates power using heat energy that has been discarded, the power cost (C _TG ) is basically 0 (zero), but is shown in FIG. 7 of the first embodiment. As described above, the power cost corresponding to the increase in the fuel consumption accompanying the decrease in the cooling water temperature may be defined.

In S20a, whether or not the maximum supply power (W _{TG_MAX} ) is less than 0 (zero), that is, whether or not the engine 1 is just started or the waste heat generator 5c is just started Therefore, it is determined whether or not the waste heat generator 5c is in a state where it cannot generate power. If the determination is affirmative, the process proceeds to S30a. If the determination is negative, the process proceeds to S31a.

In S30a, the absolute value of the maximum supply power (W _{TG_MAX} ) indicating a negative value is set as the load power (L _TG ), and the maximum supply power (W _{TG_MAX} ) is set to 0 (zero). Thereby, when the electric power generated by the waste heat generator 5c is lower than the power consumption of an auxiliary machine described later, this can be handled as an electric power load. On the other hand, in S31a, the load power (L _TG ) is set to 0 (zero).

In S40a, the maximum power supply (W _{TG_MAX} ), power cost (C _TG ), and load power (L _TG ) are transmitted to the vehicle power supply control means 13. In response to this, the vehicle power supply control means 13 determines the power generation share of each power supply source from the demand of the power load, the maximum supply power from other power supply sources such as the alternator 3 and the battery 8, and the power generation cost, The required power for each power supply source is transmitted. As a result, the required power distribution can be determined in consideration of the required load power required by the power load.

As described above, when the maximum supply power (W _{TG_MAX} ) is less than 0 (zero), the vehicle power supply control means 13 determines the load power (L _TG ) indicating the absolute value of the maximum supply power (W _{TG_MAX} ) indicating a negative value. By transmitting to, the vehicle power supply control means 13 can handle the waste heat generator 5c as one of the loads.

In S50a, the waste heat power generation control means 6 receives the required power (W _{TG_rq} ) for the waste heat generator 5c from the vehicle power supply control means 13, and in S60a, the actual power generation (W _TG ) of the waste heat power generator 5c is requested. The rotational speed (Np) of the refrigerant pump 5e and the rotational speed and torque of the waste heat generator 5c are controlled so as to be equal to the electric power (W _{TG — rq} ).

The required power (W _{TG — rq} ) is allocated so that the power generated by the waste heat generator 5c is preferentially supplied within the range of the maximum power that can be supplied by the waste heat generator 5c, as described above. The waste heat power generation control means 6 controls the rotational speed and torque of the waste heat generator 5c so as to generate power within the range.

Next, details of the procedure for calculating the maximum supply power (W _{TG_MAX} ) and the power cost (C _TG ) in S10a of FIG. 18 will be described using FIG. In S410 shown in FIG. 19, the vehicle speed (Vv), the outside air temperature (Ta), the rotational speed (Ng) of the waste heat generator 5c, the engine cooling water temperature (Tw), the engine rotational speed (Ne), and the rotational speed of the electric water pump ( Nwp), the rotational speed (Np) of the refrigerant pump 5e, and the actual value (Pp_in) of the refrigerant pressure at the inlet of the refrigerant pump 5e that controls the flow rate of the refrigerant.

  In S420, the cooling water flow rate (Fw) of engine cooling water is calculated from the engine speed (Ne) and the electric water pump speed (Nwp). Thus, about the cooling water flow rate (Fw) of engine cooling water, the flow rate of cooling water can be acquired from the rotation speed (Nwp) of the electric water pump.

  Further, the refrigerant density (ρ) is calculated from the outside air temperature (Ta) and the measured value (Pp_in) of the refrigerant pressure at the inlet of the refrigerant pump 5e, and the rotation speed (Np), discharge volume (vp), pump of the refrigerant pump 5e is calculated. The mass flow rate (Gr) of the refrigerant is calculated by multiplying by the efficiency (ηp).

  In S430, the steady state of the Rankine cycle (A → B → C → D → A →...) Of the refrigerant (for example, HFC-134a) shown in FIG. 20 from the various amounts acquired and calculated in S410 and S420 described above. The state is obtained by balance calculation. Thereby, the refrigerant | coolant pressure and enthalpy (internal energy) in each state can be estimated.

  FIG. 21 shows the specific procedure. Since the balance calculation method itself is a well-known technique, the steps S431 to S438 shown in FIG. 21 will be briefly described below. First, in S431, initial conditions are set. That is, the estimated value (Tp_in) of the refrigerant temperature at the inlet of the refrigerant pump 5e is the outside air temperature (Ta) + α (for example, about 5 [° C.]), and the estimated value (Pp_in) of the refrigerant pressure at the inlet of the refrigerant pump 5e is the inlet of the refrigerant pump 5e. Is set to the measured value (Pp_in ′) of the refrigerant pressure at. Based on the set initial condition, a temporary position “A (1)” of A in the Mollier diagram shown in FIG. 20 is calculated.

  In S432, calculation of the stroke from cycle A (1) to cycle B under the condition that the entropy is equal from the engine coolant temperature (Tw) and the mass flow rate (Gr) of the refrigerant (that is, the pressurization stroke of the refrigerant by the refrigerant pump 5e). And the predicted value (Pp_out) of the refrigerant pressure at the outlet of the refrigerant pump 5e is calculated. And the position of B in the Mollier diagram shown in FIG. 20 is calculated.

  In S433, the amount of heat transferred (input) to the refrigerant from the coolant flow rate (Fw) of the engine coolant and the outside air temperature (Tw) is calculated. Thus, by calculating the amount of heat transferred to the refrigerant from the coolant flow rate (Fw) of the engine coolant and the outside air temperature (Tw), the prediction error from the actual amount of heat transferred can be reduced.

  In S433, it is assumed that the predicted value (Pex_in) of the refrigerant pressure at the inlet of the expander 5b and the predicted value of the refrigerant pressure (Pp_out) at the outlet of the refrigerant pump 5e are substantially equal, and the process from cycle B to cycle C (that is, The heating / vaporization process) by the heat exchanger 5a is calculated, and the position of C in the Mollier diagram shown in FIG. 20 is calculated.

  In S434, it is assumed that the predicted value (Pex_out) of the refrigerant pressure at the outlet of the expander 5b and the predicted value of the refrigerant pressure (Pp_in) at the inlet of the refrigerant pump 5e are substantially equal, and the process from cycle C to cycle D under the same entropy condition. (In other words, the expansion stroke by the expander 5b) is calculated, and the position D in the Mollier diagram shown in FIG. 20 is calculated.

  In S435, the heat radiation amount of the capacitor is calculated from the vehicle speed (Vv) and the outside air temperature (Tw), and the process from cycle D to A (2) (that is, the condensation / heat radiation process by the capacitor) is calculated. The position of A (2) in the Mollier diagram shown in FIG.

  Thereby, the flow rate of the gas (air) flowing around the condenser is obtained from the vehicle speed (Vv), and the amount of heat released can be calculated based on the flow rate of the air and the temperature of the refrigerant before being radiated from the refrigerant. .

  In S436, it is determined whether or not the position of A (1) and the position of A (2) in the Mollier diagram shown in FIG. If the determination is affirmative, the position of A (1) is determined as A in S438 and the process is terminated. If the determination is negative, the position of A (2) is set to A in S437. After setting the position (1), the processes of S432 to S436 are repeated until the position A (1) and the position A (2) substantially coincide.

  Thereby, the operating point of the Rankine cycle under the input conditions is determined, and the state of the refrigerant and various performances can be predicted. The predicted value (Wex) of the mechanical output of the expander 5b, which is the input of waste heat generated power, is the difference between the predicted values of the enthalpy of the refrigerant at the inlet and outlet of the expander 5b (ΔHex) in the Mollier diagram shown in FIG. Predicted by multiplying (= Hex_in−Hex_out) by the refrigerant mass flow rate (Gr) and expander efficiency (ηex).

  Further, based on the same principle, the refrigerant pump input power (Wp) consumed by the refrigerant pump 5e can be predicted in the process from the cycle A to the B, that is, in the process of pressurizing the refrigerant by the refrigerant pump 5e. Thereby, power consumption can be predicted from the prediction result of refrigerant pressure and enthalpy.

  In S440 of FIG. 19, the measured values (Pex_in ′) and (Pex_out ′) of the refrigerant pressure at the inlet and outlet of the expander 5b are acquired. In S450, the mechanical output (Wex) of the expander 5b predicted in S430, the predicted value and the actual measurement value (Pex_in), (Pex_out), (Pex_in ′), (Pex_out ′) of the refrigerant pressure at the inlet and outlet of the expander 5b. Is used to calculate the output correction coefficient (Aw) of the expander 5b.

  Here, a method of calculating the output correction coefficient (Aw) of the expander 5b will be described with reference to FIGS. In FIG. 20, the cycle predicted from the balance calculation changes as indicated by a broken line (A → B → C → D → A →...). In this cycle, A → B indicates the pressurization process of the refrigerant by the refrigerant pump 5e, and B → C indicates the heating / vaporization process by the heat exchanger 5a. C → D represents the expansion stroke by the expander 5b, and D → A represents the condensation / heat radiation stroke by the condenser. On the other hand, it is assumed that the cycle of the actual machine changes as shown by a solid line in FIG. 20 (A ′ → B ′ → C ′ → D ′ → A ′ →...).

The predicted value (W _TG ) of the generated power of the waste heat generator 5c is obtained by multiplying the predicted value (Wex) of the mechanical output of the expander 5b by the power generation efficiency (η _G ) of the waste heat generator 5c, as shown in the following equation. The difference in power consumption (Wcp) in the waste heat power generation system 5 is taken from the thing. The predicted value (Wex) of the mechanical output of the expander 5b is the difference between the predicted value of the enthalpy of the refrigerant at the inlet and the outlet of the expander 5b (ΔHex), the mass flow rate (Gr) of the refrigerant, and the expander efficiency (ηex). Multiplied by.

(Equation 6)
W _TG = Wex × η _G −Wcp = {(1 / 3.6) × ΔHex × Gr × ηex} −Wcp
Further, the correction value (W _TG ′) of the generated power of the waste heat generator 5c is expressed by the following formula from the above formula. In the following equation, the correction value (Wex ′) of the mechanical output of the expander 5b and the correction value (ΔHex ′) of the difference between the enthalpies of the refrigerant at the inlet and the outlet of the expander 5b.

(Equation 7)
W _TG ′ = Wex ′ × η _G −Wcp = {(1 / 3.6) × ΔHex ′ × Gr × ηex} −Wcp = Wex × (Wex ′ / Wex) × η _G −Wcp
Here, by multiplying the predicted value (Wex) of the mechanical output of the expander 5b by the ratio of the enthalpy difference between the predicted cycle and the actual cycle, it is possible to calculate an accurate expander output that matches the actual refrigerant state. .

  Although it is difficult to directly measure the difference (ΔHex ′) between the correction values of the enthalpy of the refrigerant at the inlet and outlet of the expander 5b in the actual cycle, the pressure at the inlet and outlet of the expander 5b should be measured. Thus, (ΔHex ′ / ΔHex) can be estimated.

  That is, as shown in FIG. 22 (a), a right triangle CDR having a slope C of the refrigerant state on the Mollier diagram in the prediction cycle and a Mollier in the actual cycle as shown in FIG. 22 (b). Consider a right triangle C′D′R ′ having a hypotenuse of the refrigerant state stroke C ′ → D ′ on the diagram.

  Since the hypotenuses CD and C′D ′ of these two triangles move along the isentropic line in FIG. 20, they can be regarded as being substantially parallel (CD // C′D ′). The two right triangles CDR and C′D′R ′ are almost similar. Therefore, since the ratio of the length of the horizontal side in FIG. 22 is equal to the ratio of the length of the vertical side, the ratio of the enthalpy difference is changed to the ratio of the refrigerant pressure on the logarithmic axis as shown in the following equation. Can be replaced.

(Equation 8)
Aw = (ΔHex ′ / ΔHex) = (log ₁₀ Pex_in′−log ₁₀ Pex_out ′) / (log ₁₀ Pex_in−log ₁₀ Pex_out) = log ₁₀ (Pex_in ′ / Pex_out ′) / log ₁₀ (Pex_in / Pex_out)
In this way, the output correction coefficient (Aw) of the expander 5b is acquired. In S460, power consumption (Wcp) in the waste heat power generation system 5 is calculated from the sum of refrigerant pump input power (Wp) consumed by the refrigerant pump 5e and other auxiliary machine power consumption (Wc). A method of calculating power consumption (Wcp) in the waste heat power generation system 5 will be described with reference to FIG.

  In S461 shown in FIG. 23, the refrigerant pump input power (Wp) consumed by the refrigerant pump 5e is acquired. In S462, an auxiliary machine other than the refrigerant pump 5e is extracted, and it is determined whether or not it is operating in response to an instruction only from the waste heat power generation control means 6. If an affirmative determination is made here, the power consumption (Wci: i = 1 to n) of the auxiliary machine is acquired in S463. On the other hand, if a negative determination is made, the power consumption (Wci: i = 1 to n) of the auxiliary machine is set to 0 (zero) in S464.

  This is because there are auxiliary machines that are used not only for waste heat power generation but also for other purposes (for example, the cooling fan 5k also operates during the operation of the in-vehicle air conditioner). It is determined whether or not the power is consumed. If the determination is affirmative, the corresponding power consumption is counted to be subtracted from the generated power. In S465, the power consumption (Wcp) of all the auxiliary machines subtracted from the waste heat generated power is calculated.

When the power consumption (Wcp) in the waste heat power generation system 5 is obtained, in S470 shown in FIG. 19, as shown in the following equation, the predicted maximum mechanical output value ( _{Wex_MAX} ) of the expander 5b and the output of the expander 5b From the correction coefficient (Aw), the power generation efficiency (η _G ) of the waste heat power generator 5c, and the power consumption (Wcp) in the waste heat power generation system 5, the maximum supply power (W _{TG —} MAX) of the waste heat power generator 5c of the waste heat power generator 5c is obtained. .

(Equation 9)
_{W TG_MAX = Wex _MAX × Aw ×} η G -Wcp _MAX
In this way, by correcting for subtracting the maximum power consumption ( _{Wcp_MAX} ) by the auxiliary machine operating in response to a command only from the waste heat power generation control means 6, accurate maximum supply reflecting the refrigerant state of the actual machine is performed. It becomes possible to predict the power.

In addition, as shown in the above formula 9, the maximum supply power (W _{TG_MAX} ) is calculated by subtracting from the power consumption (Wcp) in the waste heat power generation system 5, but the power consumption (Wcp) in the waste heat power generation system 5 May be transmitted to the vehicle power supply control means 13 as load power (L _TG ) without subtracting.

  In this case, the net power generation amount of the waste heat power generation system 5 is grasped and managed in the vehicle power source control means 13, but the balance between the power supply and the demand is all balanced including the case where the power generation amount is not sufficient. There is an advantage that the vehicle power supply control means 13 can perform unified management.

(Modification 7)
The prediction of Rankine cycle by balance calculation in the present embodiment is a convergence calculation, so the calculation processing load is large and it is expected that calculation in real time is difficult. In such a case, the calculation result of the balance calculation may be mapped, the map may be stored in a storage means such as a memory, and prediction may be performed using this map.

(Modification 8)
Since it is clear that the refrigerant pressure (Pex_out ′) at the outlet of the expander 5b and the refrigerant pressure (Pp_in ′) at the inlet of the refrigerant pump 5e are substantially equal, the pressure sensor 5j of FIG. The refrigerant pressure (Pex_out ′) at the outlet may be the refrigerant pressure (Pp_in ′) at the inlet of the refrigerant pump 5e. In order to further improve the prediction accuracy, the refrigerant pressure at the outlet of the expander 5b is added to the refrigerant pressure (Pp_in ′) at the inlet of the refrigerant pump 5e with reference to the calculation or the map for the pressure loss of the capacitor in the cycle stroke D → A. (Pex_out ′) may be used.

(Modification 9)
In the present embodiment, the distribution of the required power to each power supply source is determined so that the total power cost, which is the total power cost of each power supply source, is minimized, but as in the first embodiment. In addition, the distribution of the required power to each power supply source should be determined so that power is supplied within the range of the maximum supply power with priority given to the power demand of the electrical system from the power supply source with a low power cost. May be.

(Modification 10)
Also in the thermoelectric generation system of this embodiment, as explained in the third modification of the first embodiment, when the electric power of the vehicle electric system is insufficient, the temperature of the engine cooling water is raised from the normal temperature, You may make it generate electric power with a thermal generator using thermal energy.

(Modification 11)
Also in the thermoelectric generation system of the present embodiment, as described in Modification 4 (FIG. 13) of the first embodiment, the power supply bus 1 connected to the alternator 3 and the power supply connected to the waste thermoelectric generation system 5 A battery 1 and a battery 2 may be disposed in each of the buses 2 and the power supply buses may be connected by different voltage bus connection means 14 such as a DC / DC converter.

(Modification 12)
Also in the thermoelectric generator system of the present embodiment, as described in the sixth modification (FIG. 15) of the first embodiment, the power bus connected to the waste heat generator 5c is connected to the high power bus of the HV battery. It may be. Thereby, the electric power by thermoelectric power generation can be utilized as electric power for driving | running | working. In addition, a large-capacity HV battery can be utilized to enable more flexible power generation operation in accordance with the use situation and conditions of the vehicle, and the fuel efficiency of the hybrid electric vehicle (HV) can be further improved.

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine control means 3 Alternator 4 Alternator control means 5 Waste heat power generation system 5a Heat exchanger 5b Expander 5c Waste heat generator 5d Generator control means 5e Refrigerant pump 5f, 5i, 5j Pressure sensor 5g Refrigerant pump motor control means 5h Water pump motor control means 5k Cooling fan 6 Waste heat power generation control means 7 Water temperature detection means 8 Battery 9 Battery state detection means 10 Bus voltage detection means 11 Current detection means 12 Load control means 13 Vehicle power supply control means

Claims (30)

A power supply control device comprising a plurality of power supply sources including a thermal generator that generates heat using thermal energy of a heat source,
Temperature detecting means for detecting a temperature of the heat source or a heat transfer medium of the heat source;
Calculating the maximum supply power that can be supplied by the thermal generator based on the temperature and the power cost, and calculating the maximum supply power and power cost of other power supply sources;
Distribution determining means for determining distribution of required power to each of the power supply sources so as to supply power within the range of the maximum supply power in preference to the power supply source having a low power cost with respect to demand power; With
Each of the power supply sources supplies the required power. A power supply control device comprising a plurality of power supply sources including a thermal generator that generates heat using thermal energy of a heat source,
Temperature detecting means for detecting a temperature of the heat source or a heat transfer medium of the heat source;
Calculating the maximum supply power that can be supplied by the thermal generator based on the temperature and the power cost, and calculating the maximum supply power and power cost of other power supply sources;
Distribution determining means for determining distribution of required power to each power supply source so that a total power cost obtained by totaling the power costs of each power supply source is minimized,
Each of the power supply sources supplies the required power.   The said calculation means calculates the increment of the fuel consumption of the said heat source at the time of the power generation by the said thermoelectric generator with respect to the unit power generation of the said thermoelectric generator as the electric power cost of the said thermoelectric generator. Power supply control device.   The heat generator uses engine cooling water as a heat transfer medium of the heat source, expands a refrigerant with heat energy of the cooling water, and generates electric power using the operating energy. The power supply control device according to any one of 1 to 3.   5. The power supply control device according to claim 4, wherein the calculation unit calculates a maximum power supply of the thermoelectric generator from a pressure before expansion of the refrigerant, a flow rate of the refrigerant, and a water temperature of the cooling water. The calculating means includes
When the cooling water temperature is lower than the lower limit value of the cooling water temperature control, the maximum power supply of the thermal generator is calculated as zero,
When the coolant temperature exceeds the lower limit value of the coolant temperature control, calculating the power approximately proportional to the difference between the coolant temperature and the lower limit value as the maximum supply power of the thermal generator. 6. The power supply control device according to claim 4 or 5, characterized in that: A power shortage detection means for detecting power shortage in a power supply system that receives power supply from the plurality of power supply sources;
The power shortage detecting means comprises a supply power restriction alleviating means for relaxing the restriction on the supply power of the thermal generator caused by falling below a lower limit value of the water temperature control when the power shortage is detected. Item 7. The power supply control device according to Item 6.   The power supply control device according to claim 7, wherein the power shortage detection unit detects that the required power exceeds the supply power.   8. The power supply control device according to claim 7, wherein the power shortage detecting means detects that the bus voltage of the power supply system is below a predetermined lower limit voltage.   The power supply control device according to any one of claims 7 to 9, wherein the supply power restriction mitigation unit lowers a lower limit value of water temperature control of the cooling water.   The supply power restriction mitigation means calculates a new restriction of the supply power based on a function map that separately defines the maximum supply power of the thermal generator or a change in internal energy of the heat transfer medium. The power supply control apparatus of any one of Claims 7-10.   The calculation means calculates the maximum supply power and power cost that can be supplied by the thermal energy of the cooling water that exceeds the target water temperature of the cooling water temperature control as the maximum supply power and power cost of the thermal generator. The power supply control device according to claim 4, wherein: Water temperature increase control means for performing water temperature increase control for increasing the water temperature of the cooling water,
The said calculation means considers the additional fuel consumption of the said heat source required for the said water temperature rise control with respect to the electric power which can be supplied by the said water temperature rise control to the electric power cost of the said thermoelectric generator. The power supply control device according to any one of 12. The plurality of power supply sources include a plurality of capacitors,
At least one of the plurality of capacitors is connected to the thermoelectric generator via a first power supply bus so as to store electric power generated by the thermoelectric generator,
The other battery is connected to a second power bus different from the first power bus,
Power supply bus connection means for connecting the first power supply bus and the second power supply bus;
The power supply control apparatus according to any one of claims 1 to 13, wherein power is transferred between the first power supply bus and the second power supply bus by the power supply bus connection means. The first power bus is a power power bus of a hybrid electric vehicle,
15. The power supply control device according to claim 14, wherein the electric power of the thermal generator is used as electric power for running the hybrid electric vehicle via the power supply bus. A power management method for a power supply control device including a plurality of power supply sources including a thermal generator that generates power using thermal energy of a heat source,
Detecting the temperature of the heat source or a heat transfer medium of the heat source;
While calculating the maximum supply power that can be supplied by the thermal generator and the power cost based on the temperature, calculating the maximum supply power and power cost of other power supply sources,
Determining the allocation of the required power to each power supply source so as to supply power within the range of the maximum supply power in preference to the power supply source having a low power cost with respect to the demand power;
The power management method for a power supply control device, wherein each of the power supply sources supplies the required power. A power management method in a power supply control device including a plurality of power supply sources including a thermal generator that generates power using thermal energy of a heat source,
Detecting the temperature of the heat source or a heat transfer medium of the heat source;
While calculating the maximum supply power that can be supplied by the thermal generator and the power cost based on the temperature, calculating the maximum supply power and power cost of other power supply sources,
Determining the distribution of required power to each power supply source so that the total power cost of the power costs of each power supply source is minimized,
The power management method for a power supply control device, wherein each of the power supply sources supplies the required power.   18. The power control according to claim 16, wherein the power cost of the thermal generator is calculated as an increase in fuel consumption of the heat source during power generation by the thermal generator with respect to unit generated power of the thermal generator. Device power management method.   The heat generator uses engine cooling water as a heat transfer medium of the heat source, expands a refrigerant with heat energy of the cooling water, and generates electric power using the operating energy. The power management method for a power supply control device according to any one of 16 to 18.   20. The power management method for a power supply control device according to claim 19, wherein the maximum power supply of the thermal generator is calculated from the pressure before expansion of the refrigerant, the flow rate of the refrigerant, and the coolant temperature. The maximum power supply of the thermal generator is
When the water temperature of the cooling water is lower than the lower limit value of the water temperature control of the cooling water, and zero,
21. The electric power that is substantially proportional to the difference between the cooling water temperature and the lower limit value when the cooling water temperature exceeds the lower limit value of the cooling water temperature control. Power management method for power control device.   When a power shortage of a power supply system that receives power supply from the plurality of power supply sources is detected, a restriction on power supply to the thermal generator caused by falling below a lower limit value of the water temperature control is relaxed. Item 22. A power management method for a power supply control device according to Item 21.   23. The power management method for a power supply control device according to claim 22, wherein the power shortage is detected when the required power exceeds supply power.   23. The power management method for a power supply control device according to claim 22, wherein the power shortage is detected when a bus voltage of the power supply system falls below a predetermined lower limit voltage.   The power management method for a power supply control device according to any one of claims 22 to 24, wherein a restriction on the supply power is relaxed by lowering a lower limit value of water temperature control of the cooling water.   26. The new limit of the supply power is calculated based on a function map in which the maximum supply power of the thermo-generator is separately determined or a change in internal energy of the heat transfer medium. The power management method of the power supply control device according to Item 1.   The maximum supply power and power cost of the thermal generator are maximum supply power and power cost that can be supplied by thermal energy of the cooling water that exceeds a target water temperature of the cooling water temperature control. The power management method for a power supply control device according to 19 or 20.   When executing the water temperature increase control for increasing the water temperature of the cooling water, the additional fuel consumption of the heat source required for the water temperature increase control with respect to the electric power that can be supplied by the water temperature increase control is the electric power of the thermal generator The power management method for the power supply control device according to any one of claims 19 to 27, wherein the power management method is added to the cost. The plurality of power supply sources include a plurality of capacitors,
At least one of the plurality of capacitors is connected to the thermoelectric generator via a first power supply bus so as to store electric power generated by the thermoelectric generator,
The other battery is connected to a second power bus different from the first power bus,
The power transfer between the first power supply bus and the second power supply bus is performed by a power supply bus connection unit that connects the first power supply bus and the second power supply bus. Item 29. The power management method for a power supply control device according to any one of Items 16 to 28. The first power bus is a power power bus of a hybrid electric vehicle,
30. The power management method for a power supply control device according to claim 29, wherein the electric power of the thermal generator is used as electric power for running the hybrid electric vehicle via the power supply bus.

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