JP5652292B2 - Regenerative system - Google Patents

Description

  The present invention relates to a regeneration system.

  An electrically heated catalyst is provided upstream of the filter, and the temperature of the filter can be raised to remove particulate matter (hereinafter also referred to as PM) from the filter. This removal of PM from the filter is referred to as filter regeneration. Then, when the low-load operation of the internal combustion engine continues during regeneration of the filter, the temperature of the exhaust gas is raised by adding fuel to the electrically heated catalyst while supplying power to the electrically heated catalyst, A technique for increasing the temperature is known (see, for example, Patent Document 1).

  However, supplying electric power to the electrically heated catalyst reduces the remaining capacity (SOC) of the battery. For this reason, it is necessary to charge the battery, and there is a risk that the fuel efficiency will deteriorate. Here, since the ease of charging of the battery (charge acceptability) changes according to the remaining capacity of the battery, the power charged during regeneration changes depending on the state of the battery. In addition, the amount of power generated during regeneration varies depending on the state of the system. That is, the efficiency during regeneration may be reduced. Furthermore, if the engine is decelerated during regeneration of the filter, the catalyst may be overheated, so the throttle provided in the intake passage may be opened. When the throttle is opened in this manner, exhaust gas having a low temperature passes through the filter, so that the temperature of the filter may be excessively lowered. If the temperature of the filter is increased again, it takes time to regenerate the filter, and a large amount of fuel and a large amount of electric power are required.

Japanese Patent Application Laid-Open No. 2008-106865 JP 2009-144513 A JP-A-7-247825 JP 2010-268639 A JP 2000-027631 A

  The present invention has been made in view of the above-described problems, and an object thereof is to increase the efficiency of regeneration.

To achieve the above object, the regenerative system according to the present invention provides:
A generator that generates electric power by converting kinetic energy into electrical energy;
A battery for storing the power;
Regenerative control means for reducing kinetic energy by generating electric power with the generator and storing the electric power in a battery;
An exhaust purification device for purifying exhaust gas provided in an exhaust passage of the internal combustion engine;
A heating element that generates heat by supplying electric power and raises the temperature of the exhaust purification device;
Regeneration means for recovering the ability of the exhaust purification device by raising the temperature of the exhaust purification device;
Deceleration control for supplying power to the heating element when the purification capability of the exhaust gas purification device is restored by the regeneration means and when the regeneration control means stores power in the battery Means,
Is provided.

Examples of the exhaust purification device include a filter that collects PM in the exhaust. This filter can oxidize and remove PM by raising the temperature of the exhaust. In this case, the reproducing means performs filter regeneration. Further, the exhaust purification device can include an NOx storage reduction catalyst (hereinafter referred to as NOx catalyst) that stores NOx in the exhaust. In the NOx catalyst, sulfur components contained in the fuel are also occluded in the same manner as NOx. The sulfur component occluded in this way is less likely to be released than NOx and accumulates in the NOx catalyst. This is called sulfur poisoning. Since the NOx purification rate of the NOx catalyst is reduced by this sulfur poisoning, it is necessary to perform a sulfur poisoning recovery process for recovering from sulfur poisoning at an appropriate time. This sulfur poisoning recovery process is performed by raising the temperature of the NOx catalyst and flowing exhaust gas having a stoichiometric or rich air-fuel ratio to the NOx catalyst. In this case, the regeneration means performs sulfur poisoning recovery. Note that the regeneration means may increase the temperature of the exhaust gas purification device with a heating element, or may increase the temperature of the exhaust gas purification device without using the heating element.

  The heating element may be provided in an exhaust passage on the upstream side of the exhaust purification device, or may be integrated with the exhaust purification device. Further, a catalyst may be supported on the heating element. An exhaust gas purification device may be provided by supporting a catalyst on the heating element. Further, the heating element may have a filter function. It is good also as an exhaust gas purification device by giving a heat generating body the function of a filter. When a catalyst is supported on the heating element and the heating element is energized, a reducing agent may be supplied from the upstream side of the heating element to generate heat.

  The regenerative control means, for example, generates power by the generator and charges the battery when the internal combustion engine is decelerated or when the vehicle on which the internal combustion engine is mounted is decelerated.

  Here, when the performance of the exhaust gas purification device is being restored by the regeneration means, if the temperature of the exhaust gas purification device falls halfway, a large amount of energy is required to raise the temperature again. , Fuel consumption worsens. On the other hand, it can suppress that the temperature of an exhaust gas purification device falls by supplying electric power to a heat generating body. Thereby, deterioration of fuel consumption can be suppressed.

  In addition, when the battery is charged by the regenerative control means, the electric power generated during the regeneration (hereinafter also referred to as the regenerative power amount) is larger when discharging at the same time than when charging only, because the resistance is reduced. Become. This increases the efficiency of regeneration. That is, the efficiency of regeneration is higher when the power is stored in the battery by the regenerative control means and when the power is supplied from the generator or the battery to the heating element at the same time, rather than separately.

  Therefore, when power is supplied to the heating element when the purification capability of the exhaust purification device is recovered by the regeneration means and when the power is stored in the battery by the regeneration control means, The regenerative electric energy can be increased while suppressing the temperature drop. Thereby, the efficiency of regeneration can be increased. In addition, by suppressing the temperature reduction of the exhaust purification device, it is possible to shorten the time required to restore the capacity of the exhaust purification device, so that the energy consumption of the entire system can be reduced. For this reason, fuel consumption can be improved.

Further, in the present invention, a heater that generates heat by supplying electric power and raises the temperature of the internal combustion engine;
In the cold state of the internal combustion engine, when supplying power to the heating element by the deceleration control means, prohibiting means for prohibiting the supply of power to the heater;
Can be provided.

The heater increases the temperature of the internal combustion engine, for example, by increasing the temperature of the lubricating oil of the internal combustion engine. Further, the temperature of the internal combustion engine may be increased by increasing the temperature of the cooling water of the internal combustion engine. When the internal combustion engine is cold, the fuel efficiency can be improved by increasing the temperature of the internal combustion engine. However, the prohibiting means prohibits the supply of power to the heater when supplying power to the heating element by the deceleration control means. As a result, the fuel consumption can be deteriorated by that amount, but the temperature of the exhaust gas is increased accordingly. Then, by prohibiting the supply of power to the heater, the amount of power supplied to the heating element can be increased. As a result, the time required for recovery of the purification capability of the exhaust emission control device can be shortened, so that the fuel efficiency of the entire system can be improved. That is, since the improvement in fuel efficiency by completing the recovery of the exhaust purification device quickly is greater than the improvement in fuel consumption by supplying electric power to the heater, priority is given to recovery of the purification capability of the exhaust purification device . Thus, fuel consumption can be improved.

  According to the present invention, the efficiency of regeneration can be further increased.

It is a figure which shows schematic structure of the internal combustion engine which concerns on an Example, and its exhaust system. 6 is a time chart showing changes in remaining battery capacity (SOC) and engine speed when the battery is discharged about 300 seconds before deceleration. It is the time chart which showed transition of the remaining capacity (SOC) of a battery and engine speed when discharging a battery just before deceleration. 6 is a time chart showing the transition of the remaining capacity (SOC) of the battery 21 and the engine speed when the battery is discharged during deceleration. It is the figure which showed the regenerative electric energy about each of the case of FIG. 3 is a flowchart illustrating a control flow according to the first embodiment. FIG. 3 is a diagram illustrating a schematic configuration of an internal combustion engine and an exhaust system thereof according to a second embodiment. 6 is a flowchart illustrating a control flow according to a second embodiment.

  Hereinafter, specific embodiments of the regeneration system according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and its exhaust system according to the present embodiment. The internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle diesel engine having four cylinders.

  An exhaust passage 2 is connected to the internal combustion engine 1. An electrically heated catalyst 3 is provided in the middle of the exhaust passage 2.

In the electrically heated catalyst 3, a catalyst having an oxidation function is supported on a catalyst carrier made of a material that generates electrical resistance and generates heat when energized. The catalyst carrier has a plurality of passages that extend in the direction in which the exhaust flows and whose cross section perpendicular to the direction in which the exhaust flows forms a honeycomb. Exhaust gas flows through this passage. Examples of the catalyst include an oxidation catalyst, a three-way catalyst, an occlusion reduction type NOx catalyst, and a selective reduction type NOx catalyst. In this embodiment, the electrically heated catalyst 3 corresponds to the heating element in the present invention. Moreover, it is good also as the electric heating type catalyst 3 by providing a catalyst downstream from a heat generating body.

The exhaust passage 2 downstream of the electrically heated catalyst 3 is provided with a filter 4 for collecting PM in the exhaust. The filter 4 may carry, for example, an oxidation catalyst, a three-way catalyst, a storage reduction type NOx catalyst, a selective reduction type NOx catalyst, and the like. In the present embodiment, the filter 4 corresponds to the exhaust purification device of the present invention. Further, the electrically heated catalyst 3 and the filter 4 may be integrated. The catalyst carrier of the electrically heated catalyst 3 may have the function of the filter 4.

  Further, an injection valve 5 for injecting a reducing agent into the exhaust gas is attached to the exhaust passage 2 upstream of the electrically heated catalyst 3. The injection valve 5 is opened by a signal from the ECU 10 described later, and injects the reducing agent into the exhaust. For example, the fuel (light oil) of the internal combustion engine 1 is used as the reducing agent, but the reducing agent is not limited thereto.

  The fuel injected from the injection valve 5 into the exhaust passage 2 reacts in the electrically heated catalyst 3. The temperature of the filter 4 can be raised by the heat generated at this time. Note that the amount of reducing agent injected from the injection valve 5 is determined based on, for example, the operating state (engine speed and fuel injection amount) of the internal combustion engine 1. The relationship among the amount of reducing agent, engine speed, and engine load can be mapped in advance.

  The reducing agent can also be supplied by discharging unburned fuel from the internal combustion engine 1. That is, an in-cylinder injection valve for injecting fuel into the cylinder is provided, and sub-injection (post-injection) for injecting fuel again during the expansion stroke or exhaust stroke after performing main injection from the in-cylinder injection valve is performed. Alternatively, by delaying the fuel injection timing from the in-cylinder injection valve, the gas containing a large amount of reducing agent can be discharged from the internal combustion engine 1. Note that the temperature of the filter 4 can be raised by energizing the electrically heated catalyst 3 without using a reducing agent.

  Further, an air-fuel ratio sensor 6 for detecting the air-fuel ratio of the exhaust and a temperature sensor 7 for detecting the temperature of the exhaust are attached to the exhaust passage 2 downstream of the filter 4.

  The internal combustion engine 1 is provided with a generator 20. The generator 20 generates power by obtaining kinetic energy from the crankshaft of the internal combustion engine 1. The generator 20 is connected to a battery 21 and a battery 31 via electric wires. Moreover, the generator 20 and the battery 21 are connected to the electrically heated catalyst 3 via electric wires. The generator 20, the battery 21, the battery 31, and the electrically heated catalyst 3 are electrically grounded. The battery 21 may be a battery having an electromotive force of 36 volts, for example. Alternatively, three batteries having an electromotive force of 12 volts may be connected in series to form the battery 21. On the other hand, the battery 31 is a battery having an electromotive force of 12 volts. An electric load is connected to each of the batteries 21 and 31. The electrically heated catalyst 3 is connected as an electrical load of the battery 21. The number of batteries and the electromotive force are not limited to these. Further, the battery 31 may not be provided.

  A first switch 22 is provided in the middle of the electric wires from the generator 20 toward the electrically heated catalyst 3 and the batteries 21 and 31. The first switch 22 connects the generator 20 to either the battery 21 or the battery 31. That is, when the first switch 22 is ON, power is supplied to the battery 21 and power is not supplied to the battery 31. On the other hand, when the first switch 22 is OFF, power is supplied to the battery 31, and power is not supplied to the battery 21 and the electrically heated catalyst 3. And according to ON-OFF of the 1st switch 22, the voltage of the generator 20 is changed by ECU10 mentioned later. On the other hand, a second switch 23 is provided in the middle of the electric wire from the generator 20 and the battery 21 toward the electrically heated catalyst 3. The second switch 23 conducts electricity when ON, and does not conduct electricity when OFF. When the second switch 23 is OFF, the power from the generator 20 and the power from the battery 21 are not supplied to the electrically heated catalyst 3.

The internal combustion engine 1 configured as described above is provided with an ECU 10 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 10 controls the operation state of the internal combustion engine 1 according to the operation conditions of the internal combustion engine 1 and the request of the driver.

  In addition to the above sensors, the ECU 10 outputs an electric signal corresponding to the amount of depression of the accelerator pedal 11 by the driver to detect the engine load, and an accelerator position sensor 12 for detecting the engine speed. 13 are connected via electric wiring, and the output signals of these various sensors are input to the ECU 10.

  On the other hand, the injection valve 5, the generator 20, the first switch 22, and the second switch 23 are connected to the ECU 10 through electric wiring, and these devices are controlled by the ECU 10. For example, at the time of deceleration of the internal combustion engine 1 or a vehicle on which the internal combustion engine 1 is mounted, regenerative control is performed to cause the generator 20 to generate power while turning on the first switch 22. The battery 21 is charged by this regenerative control. Further, the battery 31 can be charged by causing the generator 20 to generate power while turning off the first switch 22 during deceleration. Then, the ECU 10 changes the voltage of the generator 20 in accordance with the ON / OFF of the first switch 22. In this embodiment, the ECU 10 that performs the regeneration control corresponds to the regeneration control means in the present invention.

  In this embodiment, the reducing agent is supplied from the injection valve 5 to cause the reducing agent to react with the electrically heated catalyst 3, and the temperature of the filter 4 is increased by the reaction heat. Then, the PM is removed from the filter 4 by raising the temperature of the filter 4 to a temperature at which PM is oxidized. That is, the filter 4 is regenerated. At this time, the amount of reducing agent injected from the injection valve 5 may be feedback controlled based on the air-fuel ratio detected by the air-fuel ratio sensor 6. Further, the amount of reducing agent injected from the injection valve 5 may be feedback controlled based on the temperature of the exhaust gas detected by the temperature sensor 7. In this embodiment, the ECU 10 that regenerates the filter 4 corresponds to the regenerating means in the present invention.

  The regeneration of the filter 4 is performed when the amount of PM collected by the filter 4 reaches a predetermined amount. For example, since the PM amount flowing into the filter 4 is correlated with the engine speed and the engine load, the PM amount calculated from the engine speed and the engine load is integrated, and the integrated value reaches a predetermined amount. The filter 4 is regenerated. Alternatively, the differential pressure between the upstream side and the downstream side of the filter 4 may be measured, and the filter 4 may be regenerated when the differential pressure reaches a threshold value. Further, the filter 4 may be regenerated every time the vehicle travels a predetermined distance.

  In addition, when the electric heating catalyst 3 is not in an active state when the filter 4 is regenerated, electric power is supplied to the electric heating catalyst 3. Thereby, the temperature of the electrically heated catalyst 3 can be raised and activated. Then, after the electrically heated catalyst 3 is activated, a reducing agent is injected from the injection valve 5.

  In the present embodiment, when the internal combustion engine 1 or the vehicle on which the internal combustion engine 1 is mounted is decelerated during regeneration of the filter 4, power is supplied to the electrically heated catalyst 3. If it does so, it can suppress that the temperature of the exhaust gas which flows into the filter 4 at the time of deceleration falls. Furthermore, since the electric energy obtained by regeneration can be increased, the efficiency of regeneration can be improved.

Here, the influence of the discharge timing and the charge timing of the battery 21 on the remaining capacity (SOC) of the battery 21 and the amount of electric power (regenerative electric energy) obtained by regeneration will be considered. FIG. 2 is a time chart showing changes in the remaining capacity (SOC) of the battery 21 and the engine speed when the battery 21 is discharged about 300 seconds before the deceleration. FIG. 3 is a time chart showing changes in the remaining capacity (SOC) of the battery 21 and the engine speed when the battery 21 is discharged immediately before deceleration. FIG. 4 is a time chart showing changes in the remaining capacity (SOC) of the battery 21 and the engine speed when the battery 21 is discharged during deceleration. The battery 21 is discharged during the period indicated by “discharge”, and the battery 21 is charged during the period indicated by “charge”. The discharge corresponds to, for example, supplying electric power to the electrically heated catalyst 3. Charging corresponds to charging power generated by the generator 20 during deceleration. In addition, SOC has shown the ratio of the remaining capacity (Ah) with respect to a full charge capacity (Ah). In FIGS. 2, 3 and 4, the engine speed is changed in the same manner. At the time of discharging, 1 kW of power is discharged for 25 seconds.

  2, 3, and 4, the electric energy to be discharged is the same, but the SOC of the battery 21 at the completion of charging is different. Also, the amount of increase in SOC is different. That is, the SOC at the time of completion of charging is the largest in the case shown in FIG. 4 and the smallest in the case shown in FIG. On the other hand, the amount of increase in SOC during charging is greatest in the case shown in FIG.

  Here, FIG. 5 is a diagram showing the amount of electric power (regenerative electric energy) obtained by regeneration in each of the cases of FIGS. A shows the case of FIG. 2, B shows the case of FIG. 3, and C shows the case of FIG. In the case of FIG. 4 (C), the resistance is reduced by discharging simultaneously at the time of charging, so that the regenerative power amount increases. Further, when the case of FIG. 2 (A) and the case of FIG. 3 (B) are compared, the regenerative electric energy is larger in the case of FIG. It can be estimated that this is because, if discharging is performed immediately before charging, a concentration distribution is generated in the electrolytic solution of the battery 21.

  Therefore, in order to increase the amount of regenerative electric power generated by the generator 20, it is preferable to perform discharge according to the time of regeneration. That is, the regeneration efficiency can be improved by performing discharge in accordance with the regeneration. Further, in order to increase the charge amount of the battery 21, it is preferable to discharge immediately before the battery 21 is charged. That is, by performing discharging immediately before the battery 21 is charged, charge acceptability can be improved.

  Therefore, in this embodiment, in order to improve the regeneration efficiency, electric power is supplied to the electrically heated catalyst 3 during regeneration of the filter 4 and during deceleration. Thereby, it is possible to suppress a decrease in the temperature of the catalyst, and the time required for regeneration of the filter 4 can be shortened. Moreover, the amount of regenerative power can be increased. For this reason, a fuel consumption can be improved as the whole system.

  FIG. 6 is a flowchart showing a control flow according to the present embodiment. This routine is executed every predetermined time by the ECU 10.

  In step S101, it is determined whether or not the filter 4 is being regenerated. During the regeneration of the filter 4, the process includes raising the temperature of the filter 4 to a temperature at which PM is oxidized. If an affirmative determination is made in step S101, the process proceeds to step S102, and if a negative determination is made, the process proceeds to step S104.

  In step S102, it is determined whether the vehicle is decelerating. That is, it is determined whether power generation by regeneration is possible. If an affirmative determination is made in step S102, the process proceeds to step S103, and if a negative determination is made, the process proceeds to step S104.

  In step S <b> 103, power is generated by the generator 20, and the electric power at this time is supplied to the electric heating catalyst 3 and the battery 21. That is, the first switch 22 and the second switch 23 are turned on. Thereby, since the electrically heated catalyst 3 generates heat, the temperature drop of the filter 4 is suppressed. In this embodiment, the ECU 10 that processes step S103 corresponds to the deceleration control means in the present invention.

In step S104, the supply of electric power to the electrically heated catalyst 3 is stopped. That is, even if the first switch 22 is turned on, the second switch 23 is turned off. However, if the electrically heated catalyst 3 is not in an active state during regeneration of the filter 4, the second switch 23 may be turned on to supply power to the electrically heated catalyst 3.

  As described above, according to the present embodiment, the amount of regenerative power can be increased, so that the efficiency during regeneration (power generation) can be improved. For this reason, deterioration of fuel consumption can be suppressed. Moreover, since the time required for the regeneration of the filter 4 can be shortened, it is possible to suppress the deterioration of fuel consumption.

In the present embodiment, an NOx storage reduction catalyst may be provided in place of the filter 4.
In this case, if the regeneration of the filter according to the present embodiment is replaced with the sulfur poisoning recovery of the NOx storage reduction catalyst, the present embodiment can be similarly applied.

  FIG. 7 is a diagram showing a schematic configuration of the internal combustion engine and its exhaust system according to the present embodiment. Differences from the internal combustion engine 1 shown in FIG. 1 will be described. In addition, the same code | symbol is attached | subjected to the same member and description is abbreviate | omitted.

  In this embodiment, an oil heater 24 is connected in parallel with the electrically heated catalyst 3 as an electrical load. The oil heater 24 generates heat by supplying electric power and heats the lubricating oil of the internal combustion engine 1. An electric wire connected to the oil heater 24 is branched from the middle of the electric wire from the generator 20 and the battery 21 to the second switch 23, and a third switch 25 is provided in the middle of the electric wire. The third switch 25 is also controlled by the ECU 10 in the same manner as the first switch 22 and the second switch 23. When electric power is supplied to the oil heater 24 when the internal combustion engine 1 is cold, the combustion state is improved by increasing the temperature of the lubricating oil. Moreover, since the viscosity of lubricating oil falls, loss can be reduced. By these, fuel consumption can be improved. In this embodiment, the oil heater 24 corresponds to the heater in the present invention.

  However, in this embodiment, even when the internal combustion engine 1 is cold, the oil heater 24 is stopped during deceleration and when the filter 4 is regenerated. That is, the supply of power to the oil heater 24 is prohibited. As a result, the temperature of the lubricating oil does not rise and the fuel efficiency is deteriorated. However, the temperature of the exhaust gas rises accordingly, so that the temperature drop of the filter 4 can be suppressed. Then, the electric power that was scheduled to be supplied to the oil heater 24 is supplied to the electrically heated catalyst 3. Thereby, the power consumption in the electrically heated catalyst 3 increases, and the temperature of the filter 4 can be quickly raised. Then, since the regeneration time of the filter 4 can be shortened, the amount of fuel added from the injection valve 5 can be reduced. Then, the amount of improvement in fuel consumption is shortened by reducing the time required for regeneration of the filter 4 than the amount of deterioration in fuel consumption caused by stopping the oil heater 24. Therefore, the fuel efficiency can be improved as a whole system.

  FIG. 8 is a flowchart showing a control flow according to the present embodiment. This routine is executed every predetermined time by the ECU 10. In addition, about the step in which the same process as the flow shown in FIG. 6 is made, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  If an affirmative determination is made in step S102, the process proceeds to step S201. In step S201, it is determined whether or not the internal combustion engine 1 is cold. For example, if the temperature of the lubricating oil or cooling water is lower than the threshold value, it is determined that the internal combustion engine 1 is cold. The threshold here is set in advance as a temperature at which the internal combustion engine 1 is warmed up. If an affirmative determination is made in step S201, the process proceeds to step S202, and if a negative determination is made, the process proceeds to step S103.

  In step S202, the oil heater 24 is stopped. The oil heater 24 is normally operated when the internal combustion engine 1 is cold, but the oil heater 24 is stopped in step S202. Thereby, the electric power supplied to the electrically heated catalyst 3 can be increased. Further, the temperature of the exhaust can be raised. At this time, the third switch 25 is turned off. In this embodiment, the ECU 10 that processes step S202 corresponds to the prohibiting means in the present invention.

  In this way, the regeneration of the filter 4 can be completed quickly, so that the fuel efficiency of the entire system can be improved.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Exhaust passage 3 Electric heating type catalyst 4 Filter 5 Injection valve 6 Air-fuel ratio sensor 7 Temperature sensor 10 ECU
11 accelerator pedal 12 accelerator opening sensor 13 crank position sensor 20 generator 21 battery 22 first switch 23 second switch 24 oil heater 25 third switch 31 battery

Claims (1)

A generator that generates electric power by converting kinetic energy into electrical energy;
A battery for storing the power;
Regenerative control means for reducing kinetic energy by generating electric power with the generator and storing the electric power in a battery;
An exhaust purification device for purifying exhaust gas provided in an exhaust passage of the internal combustion engine;
A heating element that generates heat by supplying electric power and raises the temperature of the exhaust purification device;
Regeneration means for recovering the ability of the exhaust purification device by raising the temperature of the exhaust purification device;
Deceleration control for supplying power to the heating element when the purification capability of the exhaust gas purification device is restored by the regeneration means and when the regeneration control means stores power in the battery Means,
A heater that generates heat by supplying electric power and raises the temperature of the internal combustion engine;
In the cold state of the internal combustion engine, when supplying power to the heating element by the deceleration control means, prohibiting means for prohibiting the supply of power to the heater;
Ru equipped with a regenerative system.

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