DE102015214728A1 - Waste heat utilization assembly of an internal combustion engine and method for operating the waste heat recovery assembly - Google Patents

Abstract

Waste heat utilization arrangement of an internal combustion engine with a working medium leading a working circuit, wherein in the working circuit in the flow direction of the working medium, a feed pump, an evaporator, an expansion machine and a capacitor are arranged. In the working cycle, a high-pressure area is formed between the feed pump and the expansion machine, and a low-pressure area is formed between the expansion machine and the feed pump. The evaporator is also arranged in an exhaust tract of the internal combustion engine. In the exhaust tract, an exhaust gas bypass duct is arranged parallel to the evaporator. In the high-pressure region, a first pressure sensor is arranged.

Description

The invention relates to a waste heat utilization arrangement of an internal combustion engine and to a method for operating the waste heat utilization arrangement.

State of the art

Waste heat utilization arrangements of internal combustion engines are known from the prior art, as for example from the published patent application WO 2013/028173 A1 , The known waste heat utilization arrangement of an internal combustion engine comprises a working medium leading a working circuit, wherein in the working circuit in the flow direction of the working medium, a feed pump, an evaporator, an expansion machine and a capacitor are arranged. In the working cycle, a high-pressure area is formed between the feed pump and the expansion machine, and a low-pressure area is formed between the expansion machine and the feed pump. The evaporator is also arranged in an exhaust tract of the internal combustion engine. In the exhaust system, an exhaust gas bypass duct for bypassing the evaporator is further arranged.

The known waste heat utilization arrangement has no control or regulation of the pressures in the high pressure region or low pressure region of the working cycle.

As a result, there is a risk of overloading the components of the working cycle.

Disclosure of the invention

In contrast, the waste heat utilization arrangement of an internal combustion engine according to the invention has the advantage that control or regulation of the pressures takes place in the high-pressure region and in the low-pressure region of the working cycle. This increases the life and also the effectiveness of the waste heat utilization arrangement. Furthermore, the expansion machine can be operated particularly efficiently by controlling or regulating the working medium pressure in the high-pressure region.

For this purpose, the waste heat utilization arrangement comprises a working medium leading working circuit, wherein in the working circuit in the flow direction of the working medium, a feed pump, an evaporator, an expansion machine and a condenser are arranged. In the working cycle, a high-pressure area is formed between the feed pump and the expansion machine, and a low-pressure area is formed between the expansion machine and the feed pump. The evaporator is also arranged in an exhaust tract of the internal combustion engine. In the exhaust tract, an exhaust gas bypass duct is arranged parallel to the evaporator. According to the invention, a first pressure sensor is arranged in the high-pressure region.

As a result, depending on the pressure determined by the pressure sensor, the exhaust gas mass flow can be divided between the evaporator and the exhaust gas bypass duct. An increase in pressure in the high pressure range beyond a limit is thereby avoided. The life of the entire waste heat recovery assembly is thus increased. In addition, safe operation of the waste heat recovery device is ensured. Furthermore, the most favorable or most efficient pressure of the working medium for the expansion machine can thus be set.

If the waste heat utilization arrangement available in the exhaust tract increases, the mass flow of the working medium in the working cycle must be increased in order to operate the waste heat utilization arrangement in a specific temperature range. Particularly in the case of organic working media and the condition that superheated steam must be present at the inlet of the power output expansion machine, the temperature range within which the waste heat recovery device is allowed to operate is small. Consequently, an increasing supply of heat must be absorbed in the working circuit via an increase in the working medium mass flow. Considering a system with a constant expansion cross section, a working medium mass flow increase results in a pressure increase in the high pressure area.

In addition, with increasing heat absorption and thus increasing working medium mass flow, the cooling power requirement in the condenser increases in order to completely liquefy the working medium. Depending on the available and required cooling capacity results in a certain vapor and liquid content in the working cycle. If more cooling capacity is required than is available, the proportion of steam increases in the working circuit, whereby a pressure increase in the low pressure range may result if the fluid amount of the working medium is constant, so for example a collecting container for the working fluid is separated from the working circuit via a feed valve.

In order to limit the increase in pressure both in the low-pressure and in the high-pressure region, the exhaust gas is passed into the exhaust gas bypass passage at defined pressure limits exceeded such that the entire exhaust gas mass flow or at least a portion of the available exhaust gas mass flow past the evaporator becomes. The pressure limits are below the maximum allowable high pressure in the system.

In an advantageous development, a second pressure sensor is arranged in the low-pressure region. As a result, the pressures can be controlled very effectively both in the high pressure range and in the low pressure range. Preferably, both pressure sensors are each attached at the point of maximum pressure in the high pressure region or in the low pressure region.

Alternatively to the control, however, a control in the form of a map or a function in a control device can be used. The control of the distribution of the exhaust gas mass flow to the evaporator and to the exhaust gas bypass channel can be effected in dependence on the operating point of the internal combustion engine or in dependence on the exhaust gas mass flows and temperatures. Advantageously, the sensor system of the internal combustion engine is used for this purpose. Alternatively or additionally, modeled values from an engine control unit of the internal combustion engine can also be used.

In advantageous embodiments, an exhaust gas bypass valve upstream of the parallel circuit of the evaporator and the exhaust gas bypass passage is arranged in the exhaust system. As a result, the distribution of the exhaust gas mass flow to the evaporator and the exhaust gas bypass channel in a simple manner. A very fast and efficient pressure control of the working cycle can be achieved by the control of the exhaust gas bypass valve.

Advantageously, the exhaust gas bypass valve is designed as a proportional valve. With the version as a proportional valve, the amount of heat can be dissipated as needed to the evaporator. As a result, a higher output is achieved on the expansion machine, and the whole waste heat utilization arrangement becomes more efficient.

Alternatively, the exhaust bypass valve is designed as a switching valve. As a result, the exhaust gas bypass valve can be made particularly cost-effective.

In advantageous developments of the invention, at least one temperature sensor is arranged in the high-pressure region between the evaporator and the expansion machine. As a result, on the one hand, the working cycle can be regulated to a maximum temperature which can not be exceeded, and on the other hand, the inlet temperature and inlet pressure in the expansion machine can also be regulated so that the expansion machine is operated extremely efficiently. The efficiency of the entire waste heat recovery assembly increases thereby.

In advantageous embodiments, a further evaporator is arranged parallel to the evaporator in the working cycle. As a result, further heat energy can be supplied to the working cycle, so that the output of the expansion machine is increased.

Alternatively, the further evaporator may also be arranged in series with the evaporator in the working cycle.

Preferably, the further evaporator is also arranged in a return duct for the exhaust gas back to the internal combustion engine. As a result, two heat sources are used in the exhaust system: The exhaust heat in the return channel, which has a very high temperature level, and the exhaust heat, preferably in an end channel of the exhaust tract after exhaust aftertreatment, which is characterized by a high exhaust gas mass flow.

If you want to use these two heat sources effectively to maximize the power output of the waste heat recovery assembly, the maximum pressure in the working circuit must be selected according to the choice of working fluid in both high-pressure and low pressure range correspondingly high to the waste heat recovery assembly in operating points with particular to be able to operate a lot of exhaust gas energy. This would mean that the components in the waste heat recovery assembly would have to be designed for a higher pressure, which would usually be accompanied by an increase in weight and space requirements of the components. Although the expander power could be increased at operating points with a high pressure ratio on the expansion machine, at the same time the system costs would increase significantly, which in turn would adversely affect the economy of the waste heat recovery arrangement. The present invention, however, allows the use of both heat sources and at the same time compliance with pressure limitations within the work cycle.

This is preferably realized by the exhaust gas bypass valve in the exhaust system, with which the exhaust gas is passed over the exhaust gas bypass duct on demand on the evaporator. As a result, the heat input into the working cycle is reduced as needed, which allows an optimal design of the waste heat recovery arrangement.

In various embodiments, the exhaust gas bypass channel can be arranged parallel to the evaporator or to the further evaporator. Furthermore, both evaporators can each with an exhaust bypass duct and preferably also provided with an associated exhaust gas bypass valve.

In the following, methods for operating the waste heat utilization arrangement of the internal combustion engine are described, which include a pressure regulation or pressure control of the working cycle:

The method according to the invention for operating a waste heat utilization arrangement of an internal combustion engine has a working cycle leading to a working medium, wherein a feed pump, an evaporator, an expansion machine and a condenser are arranged in the working circuit in the flow direction of the working medium. The evaporator is also arranged in an exhaust gas tract of the internal combustion engine, wherein an exhaust gas bypass duct is arranged in the exhaust gas tract parallel to the evaporator. An exhaust bypass valve divides the exhaust gas mass flow to the evaporator and to the exhaust bypass passage. The method is characterized in that the exhaust gas bypass valve is controlled by a control unit such that a maximum system pressure of the working medium is not exceeded in the working cycle.

As a result, the control unit regulates the system pressure in the working circuit so that the pressure load of the components arranged in the working circuit does not rise above a defined limit value. This ensures a defined lifetime of the waste heat utilization arrangement. At the same time, the cost-benefit ratio of the waste heat utilization arrangement is optimized, since expensive and oversized components are avoided.

In an advantageous embodiment of the method, a map stored in the control unit for the internal combustion engine is used for the control of the exhaust gas bypass valve. As a result, the exhaust gas bypass valve can be controlled in a simple manner. On the arrangement of sensors, in particular of pressure sensors, in the working cycle can be optionally waived.

In a further advantageous embodiment, a high-pressure region is formed in the working cycle between the feed pump and the expansion machine, and a first pressure sensor is arranged in the high-pressure region. The first pressure sensor transmits signals to the controller, and the controller controls the exhaust bypass valve in response to these signals. As a result, a regulation of the system pressure in the working cycle can be carried out, namely as a function of the high pressure determined by the first pressure sensor in front of the expansion machine. The exhaust bypass valve can be controlled very quickly and efficiently. Even a short-term overload of the components of the waste heat recovery assembly is thereby avoided.

In an advantageous development, a low-pressure region is formed in the working cycle between the expansion machine and the feed pump, wherein a second pressure sensor is arranged in the low-pressure region. The second pressure sensor transmits signals to the controller, and the controller controls the exhaust bypass valve in response to these signals. As a result, the regulation of the system pressure in the working cycle also takes place for the low pressure range. The components of the low-pressure region, such as the condenser, can therefore be designed for a maximum low pressure.

Advantageously, the first pressure sensor and the second pressure sensor are each placed at the location of the highest pressure of the high-pressure region or the low-pressure region.

In advantageous embodiments of the method, the control unit determines on the basis of at least one pressure sensor - first or second pressure sensor - signals transmitted exceeding a pressure limit and then controls the exhaust bypass valve so that the exhaust gas mass flow is increased through the exhaust gas bypass channel. As a result, the exhaust gas mass flow is reduced by the evaporator, it is fed less heat energy in the working circuit and the pressure in the working circuit decreases accordingly.

In an advantageous development, a temperature sensor is arranged in the high-pressure region. The temperature sensor transmits signals to the controller, and the controller controls the exhaust bypass valve in response to these signals. As a result, on the one hand, the working cycle, especially the high pressure area can be protected from excessive temperatures, which means an increase in the service life. On the other hand, however, it is also possible to set an optimum state of the working medium with regard to pressure and temperature for the respective operating situation. The expansion machine can thus be operated very efficiently.

In an advantageous embodiment, the temperature sensor transmits signals to the control unit, and the control unit controls the feed pump as a function of the temperature signals. The control of the feed pump causes an increase or decrease of the working medium mass flow. This in turn leads to a pressure change in the working cycle. Depending on the detected pressure signal value, the control unit activates the exhaust gas bypass valve. As a result, on the one hand the working medium and especially the components in the high pressure area of Working cycle are protected from excessive temperatures, which means an increase in life. On the other hand, it is also possible to set an optimum state of the working medium with regard to pressure and temperature for the respective operating situation. The expansion machine can thus be operated very efficiently.

In an advantageous embodiment, a further evaporator is arranged parallel to the evaporator in the working cycle, wherein the further evaporator is also arranged in a return duct for the exhaust gas back to the internal combustion engine. By disposing a plurality of evaporators, the waste heat utilization assembly is made very efficient. A regulation of the system pressure in the working cycle is particularly important because in certain operating situations, a very high amount of heat can be fed via the evaporator in the working cycle.

Advantageously, a distributor valve divides the mass flow of the working medium onto the evaporator and onto the further evaporator, wherein the distributor valve is actuated by the control unit. The control unit preferably uses all data available to it for controlling the distributor valve, for example the sensor system arranged in the working circuit, or also the sensor system of the internal combustion engine.

Alternatively, two feed pumps can control the respective mass flows to the evaporator and to the further evaporator.

drawings

1 schematically shows an inventive waste heat utilization arrangement of an internal combustion engine, wherein only the essential areas are shown.

2 shows schematically a further inventive waste heat recovery assembly of an internal combustion engine, wherein only the essential areas are shown.

3 shows schematically a further inventive waste heat recovery assembly of an internal combustion engine, wherein only the essential areas are shown.

4 shows schematically yet another inventive waste heat recovery assembly of an internal combustion engine, with only the essential areas are shown.

description

1 schematically shows a waste heat recovery assembly according to the invention 1 an internal combustion engine 50 with a working medium leading working cycle 2 , The internal combustion engine 50 is in a cooling circuit 20 arranged.

The internal combustion engine 50 is fresh air on the inlet side 51 that also recirculated exhaust gas of the internal combustion engine 50 may be included. The exhaust side, the internal combustion engine 50 an exhaust tract 53 on, through the exhaust 52 is ejected from the internal combustion engine.

The working cycle 2 comprises in the flow direction of the working medium a collecting container 7 , a feed pump 6 , an evaporator 10 , an expansion machine 3 and a capacitor 4 , The evaporator 10 is at the same time in the exhaust tract 53 arranged so that the heat energy of the exhaust gas from the exhaust tract 53 to the work cycle 2 can be transferred. Optionally, the sump 7 be arranged in alternative embodiments in a secondary line or stub, not shown.

• – einen Hochdruckbereich 2a zwischen der Speisepumpe 6 und der Expansionsmaschine 3 und
• – einen Niederdruckbereich 2b zwischen der Expansionsmaschine 3 und der Speisepumpe 6.

The working cycle 2 is thus subdivided in the flow direction of the working medium into two areas:

• - a high pressure area 2a between the feed pump 6 and the expansion machine 3 and
• - a low pressure area 2 B between the expansion machine 3 and the feed pump 6 ,

In the high pressure area 2a is a first pressure sensor 11 arranged, and in the low pressure area 2 B a second pressure sensor 12 , The of the two pressure sensors 11 . 12 detected signals are a control unit 5 fed. Furthermore, in the high pressure area 2a between the evaporator 10 and the expansion machine 3 a temperature sensor 13 arranged, wherein the signals detected by him also the control unit 5 be supplied.

In the exhaust tract 53 is parallel to the evaporator 10 an exhaust bypass duct 61 arranged. Furthermore, in the exhaust system 53 in front of the evaporator 10 an exhaust bypass valve 60 arranged, which the exhaust gas mass flow to the evaporator 10 and in the exhaust bypass duct 61 divides or controls. The exhaust bypass valve 60 is preferably designed either as a switching valve or as a proportional valve and is provided by the control unit 5 driven.

The cooling circuit 20 comprises in the flow direction of the cooling medium, a coolant pump 21 , the internal combustion engine 50 , the condenser 4 and a cooler 35 with a fan 36 , where the capacitor 4 for example, between the Coolant pump 21 and the internal combustion engine 50 can be arranged. The capacitor 4 is both in the work cycle 2 as well as in the cooling circuit 20 arranged; that is the capacitor 4 withdraws from the working cycle 2 Heat energy and feeds this into the cooling circuit 20 one. In the cooling circuit 20 is still a temperature sensor 37 arranged, preferably between the coolant pump 21 and the capacitor 4 , The of the temperature sensor 37 detected signals are also the controller 5 fed.

The control unit 5 controls the exhaust bypass valve 60 and optionally also the feed pump 6 depending on the two pressure sensors 11 . 12 determined pressures and depending on the temperature sensor 13 determined temperature, so that thereby a pressure and temperature control in the working circuit 2 he follows. Furthermore, via the control of feed pump 6 and / or exhaust bypass valve 60 and over from the temperature sensor 37 determined temperature in the cooling circuit 20 also a temperature control in the cooling circuit 20 and a temperature control of the working fluid at the outlet of the condenser 4 respectively. Optionally available for temperature control in the cooling circuit 20 also the coolant pump 21 and / or the radiator 35 or the fan wheel 36 from the controller 5 be controlled. By controlling the temperature of the working medium at the outlet of the condenser 4 can be ensured that always liquid working fluid at the inlet to the feed pump 6 is available. So can the feed pump 6 be protected from cavitation, if necessary.

This option for regulating the cooling circuit 20 also applies to the following embodiments; however, was on a presentation of the refrigeration cycle 20 omitted in the accompanying figures.

Optionally, additional sensors, both in the working cycle 2 as well as in the cooling circuit 20 and in the exhaust tract 53 , used to regulate the working cycle 2 and / or the regulation of the cooling circuit 20 even more accurate and efficient, if necessary also faster.

2 schematically shows another waste heat utilization arrangement 1 an internal combustion engine 50 ,

The internal combustion engine 50 has a return channel 54 on. The internal combustion engine 50 is fresh air on the inlet side 51 and optionally also recirculated exhaust gas from the return channel 54 fed. Exhaust side, exhaust gas from the internal combustion engine 50 in the exhaust tract 53 pushed out. The exhaust tract 54 branches into the return channel 54 and into an end channel 55 , About the end channel 55 the exhaust gas, possibly also with the interposition of aftertreatment systems, not shown, to the environment.

The evaporator 10 is in the end channel 55 arranged. In the return channel 54 is another evaporator 40 arranged.

The working cycle 2 includes in the flow direction of the working medium, the feed pump 6 , a distribution valve 45 , a parallel circuit of a first branch line 41 and a second branch line 42 , the expansion machine 3 and the capacitor 4 , In the first branch line 41 is the evaporator 10 arranged, and in the second branch line 42 the other evaporator 40 ,

In alternative embodiments is also a series circuit of the first evaporator 10 and second evaporator 40 possible; a distribution valve 45 can be omitted accordingly in such embodiments.

The collection container 7 is via a branch line and a valve arrangement 70 to the work cycle 2 hydraulically connectable. This arrangement of the collection container 7 is possible as an alternative to all embodiments of the present invention.

• – den Hochdruckbereich 2a zwischen der Speisepumpe 6 und der Expansionsmaschine 3, der auch die beiden Zweigleitungen 41, 42 umfasst
• – den Niederdruckbereich 2b zwischen der Expansionsmaschine 3 und der Speisepumpe 6.

The working cycle 2 is thus subdivided in the flow direction of the working medium into two areas:

• - the high pressure area 2a between the feed pump 6 and the expansion machine 3 who also has the two branch lines 41 . 42 includes
• - the low pressure area 2 B between the expansion machine 3 and the feed pump 6 ,

In the high pressure area 2a is after the feed pump 6 the first pressure sensor 11 arranged, and in the low pressure area 2 B the second pressure sensor 12 , The of the two pressure sensors 11 . 12 detected signals are the control unit 5 fed. Between the parallel connection of the two evaporators 10 . 40 and the expansion machine 3 is at least one temperature sensor 13 arranged, wherein the signals detected by him also the control unit 5 be supplied.

In the exhaust tract 53 , more precisely in the end channel 55 , is parallel to the evaporator 10 the exhaust bypass duct 61 arranged. Furthermore, in the end channel 55 in front of the evaporator 10 the exhaust bypass valve 60 arranged, which the exhaust gas mass flow to the evaporator 10 and in the exhaust bypass duct 61 divides or controls. The exhaust bypass valve 60 is preferably designed either as a switching valve or as a proportional valve and is provided by the control unit 5 driven. This advantageously controls control unit 5 also the feed pump 6 and the distribution valve 45 and thus the Gesamtarbeitsmediummassenstrom and the division of the working medium mass flow in the two branches 41 . 42 or to the two evaporators 10 . 40 , The control unit 5 controls the exhaust bypass valve 60 , the feed pump 6 and the distribution valve 45 depending on the two pressure sensors 11 . 12 determined pressures and depending on the temperature sensor 13 determined temperature, so that thereby a pressure and temperature control in the working circuit 2 he follows.

3 shows a schematic of the 2 alternative waste heat recovery arrangement according to the invention 1 an internal combustion engine 50 , where only the essential areas are shown. In contrast to 2 takes place in the execution of 3 no regulation due to the signals of the two pressure sensors 11 . 12 but a control due to the exhaust gas mass flows and inlet temperatures at the two evaporators 10 . 40 ,

These are in the end channel 55 at the entrance to the evaporator 10 a temperature sensor 55a and a mass flow sensor 55b arranged and in the return channel 54 at the entrance to the further evaporator 40 another temperature sensor 54a and another mass flow sensor 54b arranged. Alternative to the mass flow sensors 55b and 54b the exhaust gas mass flows can be determined via models stored in the engine control unit. The control unit 5 controls the exhaust bypass valve 60 depending on the two temperature sensors 55a . 54a determined exhaust gas temperatures and in dependence of the two mass flow sensors 55b . 54b determined exhaust gas mass flows. The control is carried out based on at least one in the control unit 5 stored map.

Optionally, further sensors can also be used here, for example sensors of the internal combustion engine 50 to control the waste heat recovery assembly 1 even more accurate and efficient.

4 schematically shows yet another waste heat recovery assembly according to the invention 1 an internal combustion engine 50 , where only the essential areas are shown.

The working cycle 2 the execution of 4 comprises in the flow direction of the working medium, a parallel circuit of the first branch line 41 and the second branch line 42 , the expansion machine 3 and the capacitor 4 , In the first branch line 41 are the feed pump 6 and the evaporator 10 arranged. In the second branch line 42 are another feed pump 8th and the other evaporator 40 arranged. Optionally, the sump 7 in the work cycle 2 or be arranged in a secondary line, not shown.

The evaporator 10 is also in the end channel 55 arranged. The further evaporator 40 is also in the return channel 54 arranged. The exhaust bypass duct 61 is parallel to the evaporator 10 in the end channel 55 arranged. The exhaust bypass valve 60 is upstream of the parallel circuit from the evaporator 10 and the exhaust bypass duct 61 arranged and controls the distribution of the exhaust gas mass flow to the evaporator 10 and in the exhaust bypass duct 61 ,

The arrangement of two feed pumps 6 . 8th in a parallel circuit of two evaporators 10 . 40 is generally for all embodiments as an alternative to an arrangement of a feed pump 6 and a distribution valve 45 possible. The embodiments of the 2 and 3 may alternatively be altered accordingly.

The operation of the waste heat recovery device 1 is as follows:
The feed pump 6 promotes liquid working fluid under pressure into the evaporator 10 and / or optionally in the further evaporator 40 , In the evaporators 10 . 40 The working medium is theoretically isobaric evaporated according to the ideal Clausius-Rankine comparison cycle process and then the expansion machine 3 fed. In the expansion machine 3 the gaseous working fluid is expanded and thereby generates a mechanical power, which, for example, in the form of a torque of an output shaft of the internal combustion engine 50 or a generator can be supplied. The working medium is then in the condenser 4 liquefied again and then the sump 7 or the feed pump 6 fed.

To the working medium in the condenser 4 Being able to liquefy, it is deprived of heat energy there. Therefore, the capacitor 4 advantageously simultaneously in the cooling circuit 20 the internal combustion engine 50 arranged, for which purpose any other cooling circuit would be used.

• – der erste Drucksensor 11 im Hochdruckbereich 2a,
• – der zweite Drucksensor 12 im Niederdruckbereich 2b,
• – der Temperatursensor 13 im Hochdruckbereich 2a zwischen Verdampfer 10 und Expansionsmaschine 3
• – der Temperaturfühler 37 im Kühlkreislauf 20
• – der erste Temperatursensor 55a im Endkanal 55
• – der erste Massenstromsensor 55b im Endkanal 55
• – der zweite Temperatursensor 54a im Rückführkanal 54
• – der zweite Massenstromsensor 54b im Rückführkanal 54.

According to the invention are sensors, mainly in the working cycle 2 , arranged to the work cycle 2 to operate in a certain temperature range and pressure range and advantageously to operate the cooling circuit below a certain temperature limit. For this purpose, the following sensors can be used, although any combinations can be carried out:

• - the first pressure sensor 11 in the high pressure area 2a .
• - the second pressure sensor 12 in the low pressure range 2 B .
• - the temperature sensor 13 in the high pressure area 2a between evaporator 10 and expansion machine 3
• - the temperature sensor 37 in the cooling circuit 20
• - the first temperature sensor 55a in the end channel 55
• - the first mass flow sensor 55b in the end channel 55
• - the second temperature sensor 54a in the return channel 54
• - The second mass flow sensor 54b in the return channel 54 ,

The sensors transmit data or signals to the control unit 5 , The control unit 5 can also be fed with other data: For example, with a load or an operating point of the internal combustion engine 50 within a characteristic map, with exhaust gas mass flows in the exhaust gas tract 53 , with exhaust gas temperatures in the exhaust system 53 , or with a forward-looking route profile or load profile for the internal combustion engine 50 , All of these data can therefore be used to control the waste heat recovery device 1 be used.

According to the invention, the exhaust gas bypass channel 61 parallel to the evaporator 10 arranged to exhaust gas at the evaporator when needed 10 to be able to pass by. As a result, too high pressures and / or temperatures in the working cycle 2 avoided. An overload or rapid wear of the components of the waste heat recovery assembly 1 This avoids so that the life of the entire waste heat recovery assembly 1 increases. Advantageously, the controller controls 5 to the exhaust bypass valve 60 and so shares the exhaust gas mass flow to the evaporator 10 and on the exhaust bypass duct 61 on. In addition, the control unit 5 also the feed pump 6 to control the mass flow of the working fluid through the working cycle 2 to regulate.

In embodiments with two parallel evaporators 10 . 40 controls the controller 5 Advantageously, the exhaust gas bypass valve 60 , the feed pump 6 and the distribution valve 45 or the feed pump 6 and the further feed pump 8th at. Furthermore, the control unit 5 also the coolant pump 21 of the cooling circuit 20 To control optimal cooling or complete condensation of the working medium in the condenser 4 to achieve.

By controlling the pressures and optionally the temperatures in the high-pressure range 2a and in the low pressure area 2 B of the working cycle 2 the life of the components of the waste heat recovery assembly 1 increased and the waste heat utilization arrangement 1 operated efficiently. The heat input via the evaporator 10 - and optionally the other evaporator 40 - in the working cycle 2 is reduced as needed, which is an optimal design of the waste heat recovery assembly 1 allowed under economic aspects and at the same time a safe operation of the waste heat recovery arrangement 1 guaranteed. In addition, so can the cooling circuit 20 in certain operating points of the internal combustion engine 50 be relieved.

Alternatively to the use of the sensors can also in the control unit 5 stored maps are used. For example, then the exhaust bypass valve 60 from the controller 5 depending on an operating point of the internal combustion engine 50 be controlled. Of course, the controls of exhaust bypass valve 60 , Feed pump 6 , another feed pump 8th , Distribution valve 45 and coolant pump 21 through the control unit 5 The use of combinations of sensors and maps possible.

• – Steuerung bzw. Regelung des Abgasmassenstroms durch den Verdampfer 10.
• – Steuerung bzw. Regelung des Systemdrucks im Hochdruckbereich 2a.
• – Steuerung bzw. Regelung des Systemdrucks im Niederdruckbereich 2b.
• – Steuerung bzw. Regelung der Arbeitsmediumtemperatur, insbesondere der Dampftemperatur im Hochdruckbereich 2a.
• – Steuerung bzw. Regelung des Arbeitsmediummassenstroms durch das Verteilerventil 45 bzw. die Speisepumpen 6, 8.
• – Steuerung bzw. Regelung der Austrittstemperatur des Arbeitsmediums aus dem Kondensator 4.

The inventive method for controlling or regulating the waste heat recovery assembly 1 , in particular on the basis of the working cycle 2 mounted sensors, provide the following options:

• - Control or regulation of the exhaust gas mass flow through the evaporator 10 ,
• - Control or regulation of the system pressure in the high pressure area 2a ,
• - Control or regulation of the system pressure in the low pressure range 2 B ,
• - Control or regulation of the working medium temperature, in particular the steam temperature in the high pressure region 2a ,
• - Control or regulation of the working medium mass flow through the distribution valve 45 or the feed pumps 6 . 8th ,
• - Control or regulation of the outlet temperature of the working medium from the condenser 4 ,

For all control or regulating operations is preferably the exhaust gas bypass valve 60 controlled accordingly. In addition, for versions with multiple evaporators 10 . 40 also the distribution valve 45 and the feed pump 6 controlled, or alternatively, the two feed pumps 6 . 8th , The pressures in the high pressure area 2a and in the low pressure area 2 B are therefore regulated very quickly and efficiently. Furthermore, the regulation of the temperature in the high-pressure region is particularly advantageous 2a ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2013/028173 A1 [0002]

Claims (15)

Waste heat utilization arrangement ( 1 ) an internal combustion engine ( 50 ) comprising a working medium leading a working medium ( 2 ), whereby in the working cycle ( 2 ) in the flow direction of the working medium, a feed pump ( 6 ), an evaporator ( 10 ), an expansion machine ( 3 ) and a capacitor ( 4 ) are arranged, wherein in the working cycle ( 2 ) between the feed pump ( 6 ) and the expansion machine ( 3 ) a high pressure area ( 2a ) and between the expansion machine ( 3 ) and the feed pump ( 6 ) a low pressure area ( 2 B ), wherein the evaporator ( 10 ) also in an exhaust tract ( 53 ) of the internal combustion engine ( 50 ) is arranged, wherein in the exhaust tract ( 53 ) parallel to the evaporator ( 10 ) an exhaust gas bypass duct ( 61 ), characterized in that in the high pressure area ( 2a ) a first pressure sensor ( 11 ) is arranged. Waste heat utilization arrangement ( 1 ) according to claim 1, characterized in that in the low-pressure region ( 2 B ) a second pressure sensor ( 12 ) is arranged. Waste heat utilization arrangement ( 1 ) according to claim 1 or 2, characterized in that in the exhaust tract ( 53 ) an exhaust bypass valve ( 60 ) upstream of the parallel circuit from the evaporator ( 10 ) and the exhaust gas bypass channel ( 61 ) is arranged. Waste heat utilization arrangement ( 1 ) according to claim 3, characterized in that the exhaust gas bypass valve ( 60 ) is designed as a proportional valve. Waste heat utilization arrangement ( 1 ) according to one of claims 1 to 4, characterized in that in the high pressure area ( 2a ) between the evaporator ( 10 ) and the expansion machine ( 3 ) a temperature sensor ( 13 ) is arranged. Waste heat utilization arrangement ( 1 ) according to one of claims 1 to 5, characterized in that in the working cycle ( 2 ) parallel to the evaporator ( 10 ) another evaporator ( 40 ) is arranged. Waste heat utilization arrangement ( 1 ) according to claim 6, characterized in that the further evaporator ( 40 ) also in a return channel ( 54 ) for the exhaust gas back to the internal combustion engine ( 50 ) is arranged. Method for operating a waste heat utilization arrangement ( 1 ) an internal combustion engine ( 50 ), wherein the waste heat utilization arrangement ( 1 ) a work cycle leading a working medium ( 2 ), wherein in the working cycle ( 2 ) in the flow direction of the working medium, a feed pump ( 6 ), an evaporator ( 10 ), an expansion machine ( 3 ) and a capacitor ( 4 ) are arranged, wherein the evaporator ( 10 ) also in an exhaust tract ( 53 ) of the internal combustion engine ( 50 ) is arranged, wherein in the exhaust tract ( 53 ) parallel to the evaporator ( 10 ) an exhaust gas bypass duct ( 61 ), wherein an exhaust gas bypass valve ( 60 ) the exhaust gas mass flow to the evaporator ( 10 ) and on the exhaust gas bypass duct ( 61 ), characterized in that the exhaust bypass valve ( 60 ) from a control device ( 5 ) is controlled such that a maximum system pressure of the working medium in the working cycle ( 2 ) is not exceeded. A method according to claim 8, characterized in that for the control of the exhaust gas bypass valve ( 60 ) in the control unit ( 5 ) stored map for the internal combustion engine ( 50 ) is used. Method according to claim 8 or 9, wherein in the working cycle ( 2 ) between the feed pump ( 6 ) and the expansion machine ( 3 ) a high pressure area ( 2a ) and wherein in the high-pressure region ( 2a ) a first pressure sensor ( 11 ), characterized in that the first pressure sensor ( 11 ) Signals to the control unit ( 5 ) and the control unit ( 5 ) the exhaust bypass valve ( 60 ) in response to these signals. Method according to claim 10, wherein in the working cycle ( 2 ) between the expansion machine ( 2 B ) and the feed pump ( 6 ) a low pressure area ( 2 B ) and wherein in the low-pressure region ( 2 B ) a second pressure sensor ( 12 ), characterized in that the second pressure sensor ( 12 ) Signals to the control unit ( 5 ) and the control unit ( 5 ) the exhaust bypass valve ( 60 ) in response to these signals. Method according to claim 10 or 11, characterized in that the control unit ( 5 ) on the basis of at least one pressure sensor 11 . 12 transmitted signals determines an exceeding of a pressure limit value and the exhaust gas bypass valve ( 60 ) controls so that the exhaust gas mass flow through the exhaust gas bypass channel ( 61 ) is increased. Method according to one of claims 10 to 12, wherein a temperature sensor ( 13 ) in the high pressure area ( 2a ), characterized in that the temperature sensor ( 13 ) Signals to the control unit ( 5 ) and the control unit ( 5 ) the exhaust bypass valve ( 60 ) in response to these signals. Method according to one of claims 8 to 13, wherein in the working cycle ( 2 ) parallel to the evaporator ( 10 ) another evaporator ( 40 ), wherein the further evaporator ( 40 ) also in a return channel ( 54 ) for the exhaust gas back to the internal combustion engine ( 50 ) is arranged. A method according to claim 14, characterized in that a distributor valve ( 45 ) the mass flow of the working medium on the evaporator ( 10 ) and on the other evaporator ( 40 ), characterized in that the distributor valve ( 45 ) is controlled by the control unit.

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