WO2018050409A2

WO2018050409A2 - Hybrid system for an internal combustion engine

Info

Publication number: WO2018050409A2
Application number: PCT/EP2017/071115
Authority: WO
Inventors: Derya CAKALLIK; Michael Richter; Daniel Schlingmeier
Original assignee: Robert Bosch Gmbh
Priority date: 2016-09-16
Filing date: 2017-08-22
Publication date: 2018-03-22
Also published as: DE102016217743A1; WO2018050409A3

Abstract

The invention relates to a hybrid system (1) for an internal combustion engine (110), particularly for an internal combustion engine (110) of a vehicle. The hybrid system (1) comprises a waste heat recovery system (100) and a recuperation system (120). The waste heat recovery system (100) comprises a circuit (100a) that conducts a working medium. The circuit (100a) comprises, in the direction of flow of said working medium, a fluid supply pump (102), an evaporator (103), an expansion machine (104) and a condenser (105). The expansion machine (104) is mechanically connected to a generator (106). The recuperation system (120) comprises an electrical machine (122). The electrical machine (122) can be connected to a crankshaft (121) of the internal combustion engine (110) by means of a transmission element (123). The generator (106) and the electrical machine (122) are electrically connected to a shared energy store (10), preferably a 48V battery. The waste heat recovery system (100) and the recuperation system (120) have a shared control logic.

Description

Description title

Hybrid system for an internal combustion engine

The present invention relates to a hybrid system for an internal combustion engine, in particular for an internal combustion engine for a vehicle, for the efficient use of energy.

State of the art

Vehicles with an internal combustion engine or an internal combustion engine can be equipped with a recuperation system which, in conjunction with an electrical accumulator (battery), allows recovery of excess kinetic energy. For this purpose, an electric machine is operated as a generator when operating the brake pedal, so that kinetic energy of the vehicle is converted into electrical energy and stored in the battery. Such Rekuperationssystem is from the published patent application

DE 10 2012 208 845 AI known.

Furthermore, waste heat recovery systems for internal combustion engines from the prior art are known, for example from the published patent application DE 10 2014 218 485 AI.

Both recuperation system and waste heat recovery system are the subject of constant development to increase the efficiency and thus ultimately to reduce the fuel consumption of the internal combustion engine, especially when used in vehicles.

Disclosure of the invention The hybrid system according to the invention for an internal combustion engine, in particular for an internal combustion engine of a vehicle, has the advantage that it uses actual energy losses of the internal combustion engine particularly efficiently. It combines a waste heat recovery system and a recuperation system, using synergies, saving components and setting common parameters

Control can be advantageously combined.

For this purpose, the hybrid system comprises a waste heat recovery system and a recuperation system. The waste heat recovery system comprises a Clausius Rankine cycle leading to a working medium with an expansion machine. The expansion machine is mechanically connected to a generator. The recuperation system has an electric machine. The electric machine is connected by means of a transmission element with an output of the internal combustion engine, for example with a crankshaft. The generator and the electric machine are electrically connected to a common energy storage, preferably a 48V battery. Preferably, the Rankine cycle in the flow direction of the working medium comprises a feed fluid pump, an evaporator, an expansion machine and a condenser. The energy storage is thus - depending on the operating points of the internal combustion engine and the hybrid system - charged both via the waste heat recovery system and the recuperation system. Accordingly, the energy storage device can also provide electrical energy for a relatively long period of time for various consumers, but in particular for the internal combustion engine.

Advantageously, the waste heat recovery system and the recuperation system have a common control logic. The common control logic of the waste heat recovery system and recuperation system results in improved control algorithms for both systems. For example, the state of charge of the energy store can thus be used for controlling or regulating both systems. Likewise, the energy states of the two systems can be coordinated. In addition, an energy demand for various consumers can be determined. So it can be tuned with the energy demand energy supply. Ideally, the energy will be very efficient over as short as possible

Efficiency chain provided. In advantageous embodiments, communicating control devices, preferably a common control device, regulate the waste heat recovery system and the recuperation system by means of the common control logic. The hybrid system is thus component-saving controlled by only one control unit, which is the common

Control logic of the two systems includes or generated from this control logic control signal for both systems. Alternatively, several communicating ECUs can be used for this purpose. By using only one control unit or several communicating control units, synergies and algorithms can be used for the control logic, which take into account interactions between waste heat recovery system and recuperation system, resulting in synergies in the hybrid system. The control logic is preferably subdivided such that an energy storage manager for the state of charge of the energy storage device treats relevant input and output data and that a waste heat recovery coordinator treats the data relevant for the control of the waste heat recovery system. The energy storage manager preferably takes into account the range of services and the demand for power as well as the charging states of the energy store and optional further energy storage in the vehicle. Advantageously, the electric machine with respect to the internal combustion engine is operable both as a generator and as a motor. When the electric machine is running as an engine, for example, the electric machine supplies the crankshaft of the internal combustion engine with an additional torque, which ultimately is also obtained from the waste heat recovery system. If the electric machine runs as a generator, it acts as an engine brake, ie as a brake for the internal combustion engine, by applying torque to the crankshaft, which counteracts the torque of the internal combustion engine. In this regenerative state, the electric machine feeds energy into the energy store. By sharing the energy storage with superordinate control logic, the energy efficiency of the two systems waste heat recovery system and recuperation system is optimized. As a result, the fuel consumption of the internal combustion engine is ultimately reduced. In this case, actual energy losses of the internal combustion engine, such as heat energy of the exhaust gas and braking energy of the wheels of a vehicle, used to provide them to the energy storage available. Advantageously, the energy store serves as an intermediate buffer to enable energy flow optimization between the waste heat recovery system and the recuperation system. Due to the storage capacity of the energy storage 5 energy supply and energy demand can be coordinated with each other in a forward-looking manner.

In advantageous developments, additional consumers are attached to the energy store besides the internal combustion engine, for example a vehicle electrical system of a vehicle. This opens up the possibility of providing the required energy more efficiently, in the best case fuel neutral. As a result, components which today have the task of providing electrical energy from fuel, for example an alternator, can be relieved or even eliminated.

l s

If the waste heat recovery system supplies the electric machine with drive power via the energy store, which is coupled into the output of the internal combustion engine as additional torque, then there is direct electrical utilization of the hybrid system. As a result, the hybrid system can be considered as an electric transmission

20 operated between waste heat recovery system and recuperation system; In the corresponding operating states, an additional torque is thus coupled indirectly from the waste heat recovery system in the output of the internal combustion engine. This operation is advantageous if currently no indirect use of electrical energy is possible and an assistance of the internal combustion engine from an energy point of view seems more useful than a storage of energy in the energy storage.

If the waste heat recovery system supplies further electric consumers of the vehicle with electrical energy without intermediate storage in the energy storage device, then there is indirect electrical use of the hybrid system. Furthermore, there is an indirect use when the available energy is cached in an energy storage.

An exclusively indirect electrical utilization of the power output by the waste heat recovery system 35 or by the recuperation system alone would be, without the merger for a hybrid system described here, due to the fact that in Ver to the energy requirement of today's electrical systems high output power of the waste heat recovery system or the recuperation, not energy efficient. Only the combination of the two systems to the hybrid system opens up the possibility of releasing the generated energy by choosing between direct and indirect use as needed. The efficiency of the two individual systems is thus improved only by the summary of the hybrid system.

Furthermore, opens up the possibility of significantly more auxiliary consumers to electrify than currently possible, for example, a water pump, a compressor, an air compressor, a steering assistance, or other comfort functions due to the increased energy through the waste heat recovery system in the electrical system of the vehicle. In particular, it should be pointed out that the waste heat recovery system makes the additional electrical energy fuel-neutral, since it is obtained from the waste heat of the internal combustion engine, that is to say a loss energy. Although an alternator or the electric machine would also be able to apply the additional energy for electrified secondary consumers, but this would increase the additional load of the alternator fuel consumption and the system efficiency would be worse due to the longer loss chain.

In further embodiments, the evaporator of the waste heat recovery system is arranged in an exhaust pipe of the internal combustion engine. As a result, the heat energy of the exhaust gas of the internal combustion engine with the lowest possible transmission losses is fed into the cycle of the waste heat recovery system.

In advantageous developments, an exhaust gas bypass is connected in parallel to the evaporator in the exhaust pipe. An exhaust bypass door is disposed in the exhaust passage and divides the exhaust gas mass flow of the internal combustion engine into the evaporator and the exhaust gas bypass. This can prevent overheating of the cycle of the waste heat recovery system. Preferably, the exhaust gas bypass valve can divide the exhaust gas mass flow proportionally. A complete closing of the entrances in the evaporator or in the exhaust gas bypass is possible.

In advantageous uses, the hybrid systems described above are used in vehicles. In particular, the synergy effects through the common control logic lead to fuel savings, which is very much in mobile applications is advantageous. By increasing the efficiency of the internal combustion engine and pollutants are reduced, for example, the CO2 emissions is reduced.

In further applications, the energy storage of the hybrid system is connected to other consumers of the vehicle, for example with an electrical system, preferably via a DC-DC converter. As a result, auxiliary consumers in the vehicle, such as car radio, low beam, etc., can be supplied with electrical energy via the hybrid system.

In the following, methods according to the invention for operating the above-described hybrid system are set forth:

For this purpose, the hybrid system has a control logic which regulates both the recuperation system and the waste heat recovery system. In a method according to the invention, the control logic implements an energy flow optimization between the waste heat recovery system, the recuperation system and an energy requirement of the vehicle. By synergistic effects already described above, for example, the energy requirements of other auxiliary consumers of the vehicle can ideally be operated fuel neutral.

In an advantageous development, the control logic determines a state of charge of the energy store, an energy requirement of the vehicle and an energy supply of the hybrid system. The state of charge is a central variable for controlling the hybrid system, which is optimized with knowledge of energy supply and energy demand or energy demand. The state of charge determines, especially for the comparatively slow waste heat recovery system, the regulation or control of the components and serves as an intermediate buffer to compensate for short-term fluctuations in energy supply and / or energy demand.

In an advantageous embodiment of the method, the control unit or the control logic determines a maximum permitted output power of the generator as a function of the state of charge, the energy supply and the energy requirement. As a result, an overload of the energy storage is prevented. In advantageous developments, the control unit or the control logic for determining the change in the state of charge takes into account the future energy requirement of the Vehicle, especially by secondary consumers. Preferably, the control logic can control or regulate the operation of the auxiliary consumers. Such auxiliary consumers may be, for example: a vehicle electrical system, a water pump, an air-conditioning compressor, a steering assistance, a compressor or comfort functions of a vehicle. As a result, the control unit can control the waste heat recovery system and its components as well as the secondary consumers in a predictive manner, which is particularly advantageous because the waste heat recovery system reacts relatively slowly. Preferably, the energy storage manager actively controls the auxiliary consumers according to the energy supply of the hybrid system.

In advantageous embodiments, the control logic predicts the development of the waste heat of the internal combustion engine and the development of the energy requirement of the secondary consumers. As a result, future energy supply and future energy demand can be better calculated. This allows a more efficient regulation between energy supply and energy demand.

In advantageous embodiments, the waste heat recovery system has a parallel to the expansion machine switched bypass line. A bypass valve divides the mass flow of the working medium into the expansion machine and into the bypass line. The bypass valve can also the inflow of the working medium in the

Stop the expansion machine or the bypass line completely. When the maximum output power is exceeded, the control unit controls the bypass valve in such a way that the mass flow of the working medium into the expansion machine is reduced. As a result, the rotation energy provided to the generator is also reduced, so that the output of the waste heat recovery system is reduced. An overload of the energy storage is thus avoided.

In advantageous embodiments, the waste heat recovery system has a parallel to the evaporator connected exhaust gas bypass. An exhaust bypass door divides the exhaust gas mass flow of the internal combustion engine into the evaporator and into the exhaust gas bypass. The exhaust gas bypass flap can also completely prevent the inflow of the exhaust gas into the evaporator or into the exhaust gas bypass. When the maximum output power is exceeded, the control unit controls the exhaust gas bypass flap in such a way that the mass flow of the exhaust gas into the evaporator is reduced. This also reduces the heat energy available to the circuit, so that the output of the waste heat recovery system is reduced. An overload of the energy storage is thus avoided.

Brief description of the drawings

Embodiments of the invention are illustrated in the drawings and will be described in more detail below. Show it:

1 shows schematically a hybrid system for an internal combustion engine of a vehicle, wherein only the essential areas are shown, FIG. 2 shows schematically a hybrid system with control unit and control signals,

Fig. 3 shows schematically a control logic of a hybrid system with input and output signals.

Embodiments of the invention

Fig.l shows a schematic hybrid system 1 for an internal combustion engine 110 of a vehicle, wherein only the essential areas are shown. The hybrid system 1 includes a waste heat recovery system 100 and a recuperation system 120.

The internal combustion engine 110 is supplied with oxygen via an air supply 112; the exhaust gas discharged after the combustion process is discharged from the engine 110 through an exhaust pipe 111. The internal combustion engine 110 is connected via a clutch 119 mechanically separable with a transmission 115 of the vehicle. The transmission 115 includes a plurality of gears 116 that may be selected during operation of the vehicle. The gears determine a gear ratio. Via the drive shaft and the wheels 117, the torque generated by the internal combustion engine 110 is transmitted to the road. The waste heat recovery system 100 comprises a working medium leading Clausius Rankine cycle 100a, which includes a feed fluid pump 102, an evaporator 103, an expansion machine 104 and a condenser 105 in the direction of flow of the working medium. Parallel to the expansion machine 104, a bypass line 108a is connected to a bypass valve 108, so that the working medium can be guided by the expansion machine 104 depending on the operating point or passed by the bypass line 108a. The working medium can be further fed as needed via a branch line from a sump 101 and a valve unit 101a in the circuit 100a. The collecting container 101 may alternatively be incorporated into the circuit 100a.

The evaporator 103 is connected to the exhaust pipe 111 of the internal combustion engine 110, thus uses the heat energy of the exhaust gas of the internal combustion engine 110. Parallel to the evaporator 103, an exhaust gas bypass 113 is connected, wherein an exhaust gas bypass flap 114 is disposed in the exhaust pipe 111, that they Exhaust gas mass flow to the evaporator 103 and the exhaust gas bypass 113 can arbitrarily split as needed. As a result, the circuit 100a can be protected against overheating, for example. The expansion machine 104 is connected to a generator via an output shaft 104a

106, so that the rotational energy generated in the expansion machine 104 is converted into electrical energy. For example, the expansion engine 104 may be a turbine, and in the embodiment of FIG. 1, the expansion engine 104, the bypass valve 108, the output shaft 104a, and the generator 106 are combined to form a turbine-generator unit 107. In further embodiments, a transmission can also be interposed between the expansion engine 104 and the generator 106.

The operation of the waste heat recovery system 100 is as follows:

Liquid working medium is conveyed by the feed fluid pump 102, possibly from the collecting container 101, into the evaporator 103 and vaporized there by the heat energy of the exhaust gas of the internal combustion engine 110. The vaporized working fluid is subsequently expanded in the turbine or expansion engine 104, releasing mechanical energy to the generator 106. Subsequently, will the working medium in the condenser 105 is liquefied again and returned to the collecting container 101 or fed to the feed fluid pump 102.

The recuperation system 120 of the internal combustion engine 110 includes an electric machine 122 and a transmission element 123. The electric machine 122 can be operated both as a generator and as a motor. The electric machine 122, for example a claw-pole machine, is connected to a crankshaft 121 of the internal combustion engine 110 via the mechanical transmission element 123, for example a belt drive. Alternatively, any mechanical connection between the engine 110 and the electric machine 122 would be possible. In this case, the arrangement of the transmission element 123 is also possible between the internal combustion engine 110 and the transmission 115.

The internal combustion engine 110 is a heat engine that converts chemical energy of a fuel into mechanical work by combustion. The combustion takes place in a combustion chamber in which a mixture of fuel and ambient air is ignited. The thermal expansion of the hot gas is used to move a piston.

The recuperation system 120 recovers the kinetic energy as electrical energy during braking. This is achieved as a rule by the fact that the electric machine 122 is operated as a generator (regenerative). By the mechanical power consumption of the electric machine 122, a braking effect transmitted by the crankshaft 121 is achieved while electric power is recovered at the same time.

The output or the crankshaft 121 of the internal combustion engine 110 can both be accelerated and braked by the electric machine 122, depending on whether the electric machine 122 is operated as a generator or as a motor. For this purpose, the electric machine 122 is connected to an electrical energy store 10, such as a 48V battery. The electric machine 122 is thus able to reduce the rotational speed of the crankshaft 121 in both regenerative operation and in engine operation. The energy storage 10 serves both for driving the electric machine 122 and for storing electrical energy generated by the electric machine 122 is produced. In addition, the energy store 10 can be connected via a DC / DC converter 20 to an electrical system 30, for example a 12V or 24V vehicle electrical system, to a starter battery and further electrical consumers. The optional DC / DC converter 20 of the hybrid system 1 is used to provide the electrical power provided by the waste heat recovery system 100 to the conventional auxiliary consumers, such as 24V auxiliary consumers, which relieves the electrical machine 122. Optionally, 48V high power consumers can also be powered directly from the waste heat recovery system 100.

According to the invention, the energy store 10 is also connected to the generator 106 of the waste heat recovery system 100. Energy is thus supplied to the energy store 10 from the waste heat recovery system 100 and from the recuperation system 120.

The energy storage 10 of the hybrid system 1, in addition to the buffering of electrical energy from the Rekuperationsbetrieb the Rekuperationssystems 120, also used for caching the electrical energy generated by the waste heat recovery system 100 when the state of electrical system 30, hybrid system 1 and engine 110, a direct coupling of the Energy via the electric machine 122 into the crankshaft 121 or use for auxiliary consumers such as the electrical system 30 does not allow. If the energy is released from the energy store 10 to the crankshaft 121, this is a direct electrical use. If the energy is delivered to the electrical system 30, this is an indirect electrical use.

Thus, the following advantages can be achieved for the hybrid system 1 of an internal combustion engine 110 for a vehicle, for example a passenger car or a lorry:

Common use of the electric machine 122: via the electric machine 122, the energy store 10 is electrically charged when the electric machine 122 is running in generator mode. When the electric machine 122 is in engine operation, the crankshaft 121 is supplied with energy from the energy store 10. The energy storage 10 is operating point dependent both of the generator 106 of the Abwärm recovery system 100 as well as from the electric machine 122 of the Rekuperationssystems 120 filled with energy.

Sharing the energy storage 10 as a cache; Preferably, the buffer 10 is designed as a 48V battery.

Common use of the DC / DC converter 20 for the supply of conventional auxiliary consumers, for example, to supply the electrical system 30 with a voltage of 24V.

Possibility of using a common control unit for the waste heat recovery system 100 and the recuperation system 120.

Possibility of optimizing components of the hybrid system 1. For example, the electrical machine 122 can be relieved by the waste heat recovery system 100 and thus also be dimensioned smaller.

Furthermore, there are the following advantages with regard to the electrical secondary consumers or the entire vehicle electrical system:

Indirect electrical utilization of the power dissipated by the exhaust heat recovery system 100 would not be optimized without the integration with the hybrid system 1 described herein due to the high output of the exhaust heat recovery system 100 relative to the energy requirements of today's vehicle electrical system. Only the combination of the two systems waste heat recovery system 100 and recuperation system 120 to the hybrid system 1 opens up the possibility to release the energy generated again by being able to choose between direct and indirect use as needed.

Due to the increased by the waste heat recovery system 100 energy supply in the energy storage 10 and thus also in the electrical system 30, the possibility opens up significantly more auxiliary consumers to electrify than currently possible. Such auxiliary consumers may be, for example, a water pump, an air-conditioning compressor, a steering assistance, a compressor or comfort functions. In particular, it is important here that the waste heat recovery system 100 provides the additional electrical energy fuel neutral, since it is based on the waste heat of the engine or the internal combustion engine 110, so usually is completely loss energy. FIG. 2 shows a hybrid system 1, as described in FIG. In addition, however, now the control of the hybrid system 1 is outlined. For this purpose, the hybrid system has a control unit 50. The control unit 50 receives input signals from the internal combustion engine 110, the generator 106 and the electric machine 122. Preferably, the control unit 50 also receives further signals, for example from temperature and pressure sensors arranged in the circuit 100a. For simplicity, the illustration refers to only one control unit 50. In principle, it is also possible to distribute the functionalities to a plurality of control units which communicate with one another.

The controller 50 sends signals to the engine 110, the generator 106, the electric machine 122, the exhaust bypass door 114, the bypass valve 108, the feed fluid pump 102, and the valve unit 101a. In addition, the control unit 50 can receive signals from other components or send signals to them, for example, the vehicle electrical system 30 with the control unit 50 and / or with the

DC-DC converter 20 communicate.

3 shows schematically a control logic with input and output signals. In the embodiment of FIG. 3, the control logic is arranged in a common control device 50, but could alternatively also be distributed over a plurality of control devices. The control unit 50 is part of a hybrid system 1 for an internal combustion engine 110 of a vehicle, as sketched in FIG. The control logic includes an energy storage manager 51, a waste heat recovery coordinator 52, a torque coordinator 53 and a vehicle coordinator 54. Further, the control logic includes a generator controller 55, a pump controller 56, a tank controller

57 and a safety controller 58. However, this subdivision of the control logic to individual coordinators or controllers is to be understood in the software, physically the controller 50 may be a unit. The generator controller 55 controls or controls the generator 106, preferably via a

Speed control or speed control of the output shaft 104a. The pump regulator 56 controls the feed fluid pump 102 with respect to the mass flow of the working medium; the control or control of the feed fluid pump 102 is advantageously carried out as a pressure and / or temperature control or control of the working fluid in the circuit 100a between the feed fluid pump 102 and capacitor

105. For example, sensor signals of a temperature sensor can be used for this purpose Evaporator 103 and expansion machine 104 can be used. The tank controller 57 regulates or controls a pressure in the low-pressure region of the circuit 100a, that is, between the expansion engine 104 and the feed fluid pump 102. This can be done, for example, by activating the valve unit 101a. The safety controller 58 controls the bypass valve 108 and the Abgasbypassklappe 114. This is a

Overheating of the circuit 100a and / or damage to the expander 104 is avoided.

The energy storage manager 51 receives an actual charge signal 511 from the energy storage device 10. The actual charge signal 511 indicates the charge state of the energy storage device 10, that is, for example, a 48V battery. Optionally, the energy storage manager 51 receives a further actual charge signal 515 from a further energy store 15 if the vehicle has such a further energy store 15. In addition, the energy storage manager 51 receives a demand signal 513 from sub-users, such as the on-board network 30. The demand signal 513 indicates

Energy requirement of the secondary consumers.

The energy storage manager 51 further receives an actual recovery power signal 61 and / or a prediction recovery power signal 62 from the waste heat recovery coordinator 52. The actual recovery power signal 61 indicates the actual power generated in the expansion engine 104; or which the generator 106 supplies to the energy store 10. The prediction recovery power signal 62 indicates a predicted power that will be generated in the expansion engine 104 or that the generator 106 will provide to the energy storage 10. The predicted performance can also be a predicted time course of a performance. The prediction can be arbitrarily complex; For example, sensor data of the internal combustion engine or a planned route profile can be used. The energy storage manager 51 sends a marginal power signal 63 to the waste heat recovery coordinator 52. The marginal power signal 63 indicates the maximum allowable power that may be generated in the expansion engine 104, or which the generator 106 may supply to the energy storage 10, ie one maximum permitted output power of the generator 106. The limit power signal 63 can also indicate a time profile for the future maximum permitted output power. The energy storage manager 51 sends a charge state signal 64 to the Torque coordinator 53. The state of charge signal 64 indicates the state of charge of the energy store 10, ie the energy stored in the energy store 10. Furthermore, the state of charge signal 64 can also indicate how the change in the state of charge is, that is, whether the energy storage 10 is being filled or emptied.

Optionally, the energy storage manager 51 may also send a controller signal 512 to the DC-DC converter 20. The energy supplied to the energy storage device 10 or the energy dissipated by it can be subjected to high fluctuations. By means of the controller signal 512, the DC-DC converter 20 can, for example, change an electrical voltage supplied to the electrical system 30. This may be necessary, for example, when switching between the supply of different secondary consumers.

The waste heat recovery coordinator 52 sends the actual regeneration power signal 61 and / or the prediction recovery power signal 62 to the energy storage manager 51 and receives the marginal power signal 63 from the energy storage manager 51. Further, the exhaust heat recovery coordinator 52 receives a motor data signal 65 from the vehicle coordinator 54. The engine data signal 65 includes engine data of the engine 110, such as a rotational speed of the crankshaft 121 or a torque of the crankshaft 121. The engine data signal 65 may also include exhaust gas data of the internal combustion engine 110, for example, an exhaust gas temperature or an exhaust gas mass flow, which by the Exhaust pipe 111 flows. The engine data signal 65 may furthermore also contain data of the vehicle management system, for example a maximum cooling water temperature of the internal combustion engine 110.

The exhaust heat recovery coordinator 52 sends a speed signal 521 to the generator controller 55. The speed signal 521 indicates a target speed for the generator 106. As a result, for example, the electrical voltage generated in the generator 106 can be regulated. The waste heat recovery coordinator 52 sends a setpoint

Signal 522 to the pump controller 56. The command signal 522 indicates a target temperature or pressure, in particular as the inlet temperature or inlet pressure of the working fluid into the expansion engine 104. The waste heat recovery coordinator 52 sends a pressure signal 523 to the tank controller 57. The pressure signal 523 indicates a target pressure for the low-pressure region of the circuit 100 a, wherein this pressure can be regulated, for example, via the valve unit 100 a. Of the Exhaust heat recovery coordinator 52 sends a threshold signal 524 to safety controller 58. Threshold signal 524 indicates a maximum pressure or temperature of the working fluid in circuit 100a, particularly between evaporator 103 and expander 104. The limit signal is further processed in the safety controller 58 and for the control of the bypass valve

108 and the exhaust bypass door 114 is used.

The vehicle coordinator 54 receives a driver signal 541. The driver signal 541 includes data transmitted by the driver of the vehicle: for example, these are the accelerator pedal position, the brake pedal position, or the gear selection for the transmission 115 of the vehicle

Vehicle. The driver ultimately wants to control the speed and the acceleration of the vehicle, thereby physically torques or

Braking torques requested. The vehicle coordinator 54 transmits the engine data signal 65 with the operation data of the engine 110 to the exhaust heat recovery coordinator 52. Further, the vehicle coordinator 54 sends a vehicle state signal 66 and a target torque signal 67 to the torque coordinator 53. The vehicle state signal 66 includes the state of motion of the vehicle The torque command signal 67 comprises a torque desired by the driver on the wheels 117 and thus maintaining or changing the torque of the crankshaft 121. The torque coordinator 53 receives the vehicle state signal 66 and the target torque signal 67 from the vehicle coordinator 54 and the state of charge signal 64 from the energy storage manager 51. From this, the torque coordinator 53 determines a target torque signal 531 which it sends to the engine 110 and a torque Signal 532, which he sends to the electric machine 122. The target torque signal 531 gives the internal combustion engine 110 a desired torque, which it is to feed into the crankshaft 121. And the torque signal 532, the electric machine 122 before another target torque, which is to feed the electric machine 122 in the crankshaft 121. The further setpoint torque can be a torque (boosting) accelerating the crankshaft 121 or a (recuperating) torque retarding the crankshaft 121. Thus, the torque signal 532 also includes information as to whether the electric machine 122 should operate as a generator or as a motor.

The common control logic for a waste heat recovery system 100 and a recuperation system 120 may be distributed to a plurality of controllers 50 or, alternatively, integrated into a controller 50. Importantly, information from waste heat recovery system 100 and recuperation system 120 are run together and shared.

This common control logic allow not only the known functionalities of a recuperation system 120 - namely supply auxiliary consumers load energy storage 10 (recuperation) and feed torque into the crankshaft 121 (boosting) - further new additional functionalities:

Direct electrical utilization of the recovered power from the exhaust heat recovery system 100 in the powertrain.

Indirect electrical use of the power obtained from the waste heat recovery system 100 by auxiliary consumers, for example by the electrical system 30. Indirect electrical use of the power obtained or energy from the waste heat recovery system 100 by caching in the energy storage 10th

The exhaust heat recovery system 100 has a higher-level coordinator, the waste heat recovery coordinator 52, which controls the exhaust heat recovery system 100 depending on the state of the engine 110 and the vehicle state, respectively. The waste heat recovery coordinator 52 is therefore connected to the vehicle coordinator 54 and receives information about the current state of the internal combustion engine 110, in particular engine torque and engine speed, as well as information about the current exhaust gas data, in particular exhaust gas temperatures and exhaust gas mass flows, which are used for thermal control of the waste heat recovery system 100.

In addition, the vehicle coordinator 54 has the ability to make requests to the exhaust heat recovery coordinator 52 resulting from the thermal management of the vehicle 110. For example For example, at high ambient temperatures, the thermal performance of the exhaust heat recovery system 100 may be reduced to relieve the vehicle cooling system and limit the use of the vehicle fan, which has a positive effect on fuel demand due to the high power requirements of the vehicle fan.

The waste heat recovery coordinator 52 further determines the target values for the subordinate controls / controls of the waste heat recovery system 100:

Speed control by the generator controller 55 having a communication interface to the generator 106 coupled to the expander 104.

High-pressure and / or temperature control or control by the pump controller 56, the speed of the feed fluid pump 102, a mass flow or a volume flow, and thus the high pressure or the temperature depending on the available exhaust gas exergy controls.

Low-pressure control or control (optional) by the tank controller 57, which leads via the collecting container 101, the low-pressure region of the waste heat recovery system 100 for the purpose of energy optimization.

Limiting or safety functions by the safety controller 58, which ensure compliance with the permissible operating parameters of the circuit 100a via the bypass valve 108 and / or the exhaust gas bypass flap 114. The bypass valve 108 and the exhaust gas bypass flap 114 and the associated control can be embodied for example as proportional valves. The energy storage manager 51 controls the energy flows of the functions supply auxiliary consumption, recuperation and boosting. By integrating the exhaust heat recovery system 100 into the hybrid system 1, the energy storage manager 51 additionally obtains the above-described functions for directly and indirectly utilizing the power recovered from the exhaust heat recovery system 100. In particular, the energy storage manager 51 is provided with the ability to switch between direct and indirect electrical usage as needed. Simultaneous direct and indirect use is also possible.

In order to optimally control the energy flows of the entire hybrid system 1, the waste heat recovery coordinator 52 also has the option of informing the energy storage manager 51 about the current as well as the future electrical output. the output power of the waste heat recovery system 100 and the generator 106 to provide. Conversely, the energy storage manager 51 has the possibility of the waste heat recovery coordinator 52 information about the state of the electrical system to transmit, in particular the maximum allowable electrical output power of the generator 106th

The energy storage manager 51 has the ability to determine the state of charge of any conventional batteries or other energy storage 15 of the vehicle and the energy storage 10, these data being used, inter alia, to limit the performance of the waste heat recovery system 100, e.g. the maximum state of charge of the batteries (energy storage 10, additional energy storage 15, etc.) is achieved.

For the purpose of feedforward control or for reasons of stability of the electrical system 30 in the case of high-energy consumers, the energy storage manager 51 has the option of considering the current and / or future requirements of secondary consumers.

For direct electrical use, the energy storage manager 51 (or optionally also the waste heat recovery coordinator 52) has an interface to the torque coordinator 53, via which the torque of the internal combustion engine 110 can be lowered, if additional power through the electric machine 122 in the drive train or in the Crankshaft 121 is coupled. Depending on the performance of the transmission element 123, this is necessary for reasons of ride comfort or for safety reasons.

In an expanded embodiment, the control unit 50 has prediction functions which, starting from the current operating point of the internal combustion engine 110, predict the development of the exhaust heat and thus of the electrical output of the waste heat recovery system 100. As described above, such information may be provided to the energy storage manager 51 for energy flow optimization. For example, if the internal combustion engine 110 is in a high-load operating point, it is foreseeable that the available waste heat output will increase. This information can be used specifically in the energy storage manager 51 in order to lower the charge state of the energy store 10 in a forward-looking manner and to provide capacity for the following thermal peak. The common control logic of the hybrid system 1 via the above-described components of the control unit 50 has the following advantages:

Only by the common control logic is a demand-driven change between direct and indirect electrical use of the power from the waste heat recovery system 100 possible. As a result, depending on the energy requirement of the electrical system 30 or of the vehicle, the power of the waste heat recovery system 100 can either be used for the drive train - ie for the crankshaft 121 - or for the auxiliary consumers or for the electrical system 30 or be temporarily stored in the energy store 10 , which increases the energy efficiency of the waste heat recovery system 100 and thus reduces the fuel consumption of the vehicle.

Another advantage derives from the different dynamics of recuperation system 120 and waste heat recovery system 100. While the power of electric machine 122 of recuperation system 120 may vary rapidly, waste heat recovery system 100 has high thermal inertia, thereby increasing the output electrical power of generator 106 for a relatively long time is comparatively constant. The total power requirement for direct and indirect use or for charging the energy storage device 10 can thus be broken down into a basic and a peak load component, with only the latter still having to be covered by the electric machine 122 or a further generator or a further energy store 15. On the one hand, this makes it possible to optimize the efficiency chains of the power generation, on the other hand, the electric machine 122 and / or the further generator can be made smaller, which in turn saves costs and weight.

Furthermore, the possibility of extrapolating the relatively dynamic electrical energy balance of the recuperation system 120 as well as the relatively slow available thermal energy of the waste heat recovery system 100 into the future through predictive functions opens up and can be taken into account in energy management. For example, at the beginning of full-load phases of the internal combustion engine 110, an increase in the exhaust gas heat in the range of a few minutes into the future is foreseeable. In such situations, when the state of charge of the energy storage device 10 is lowered, more storage capacity is available for storing the following thermal peak power. Within the common control logic, therefore, one also uses the prediction functions for the prediction of the operating points of internal combustion engine 110 and waste heat recovery system 100, electrical power production and demand (especially indirect use) can be better adjusted over extended periods of time, resulting in a further increase in efficiency, thereby enabling a reduction in fuel consumption.

Claims

A hybrid system (1) for an internal combustion engine (110), in particular for an internal combustion engine (110) of a vehicle, the hybrid system (1) comprising a waste heat recovery system (100) and a recuperation system (120), wherein the waste heat recovery system (100) includes a Working medium leading Clausius-Rankine cycle (100a) with an expansion machine (104), wherein the expansion machine (104) is mechanically connected to a generator (106), wherein the Rekuperationssystem (120) comprises an electric machine (122), wherein the electric machine (122) can be connected to an output (121) of the internal combustion engine (110) by means of a transmission element (123), characterized in that the generator (106) and the electric machine (122) are electrically connected to a common energy store (10), preferably a 48V battery connected.

2. hybrid system (1) according to claim 1, characterized in that the waste heat recovery system (100) and the Rekuperationssystem (120) have a common control logic.

3. hybrid system (1) according to claim 2, characterized in that communicating control units, preferably a common control unit (50), the waste heat recovery system (100) and the Rekuperationssystem (120) by means of the common control logic regulate.

4. hybrid system (1) according to one of claims 1 to 3, characterized in that the electric machine (122) with respect to the internal combustion engine (110) is operable both as a generator and as a motor.

5. hybrid system (1) according to one of claims 1 to 4, characterized in that the energy store (10) serves as an intermediate buffer to enable energy flow optimization between the waste heat recovery system (100) and the Rekuperationssystem (120).

6. hybrid system (1) according to one of claims 1 to 5, characterized in that the evaporator (103) is further arranged in an exhaust pipe (111) of the internal combustion engine (110).

7. hybrid system (1) according to claim 6, characterized in that in the exhaust pipe (111) parallel to the evaporator (103) an exhaust gas bypass (113) is connected, wherein an exhaust gas bypass valve (114) the exhaust gas mass flow of the internal combustion engine (110) in the evaporator (103) and into the exhaust gas bypass (113) divides.

8. Vehicle with an internal combustion engine (110) with a hybrid system (1) according to one of claims 1 to 7.

9. Vehicle according to claim 8, characterized in that the energy store (10) is electrically connected to further consumers of the vehicle, for example with an electrical system (30).

10. A method for controlling a hybrid system for an internal combustion engine of a vehicle, wherein the hybrid system comprises a waste heat recovery system and a recuperation system, wherein the waste heat recovery system determines a work cycle leading to a combustion medium. Rankine cycle (100a) with an expansion machine (104), wherein the expansion machine (104) is mechanically connected to a generator (106), wherein the Rekuperationssystem (120) comprises an electric machine (122), wherein the electric machine (122 ) by means of a transmission element (123) with an output (121) of the internal combustion engine (110) is connectable, wherein the generator (106) and the electric machine (122) are electrically connected to a common energy store (10), wherein the waste heat recovery system (100 ) and the recuperation system (120) have a common control logic,

characterized in that the control logic performs energy flow optimization between the waste heat recovery system (100), the recuperation system (120) and an energy demand of the vehicle.

11. A method for controlling a hybrid system (1) according to claim 10, characterized in that the control logic a state of charge of the energy storage (10), an energy demand of the vehicle, in particular of secondary consumers, and determines an energy supply of the hybrid system (1).

12. A method for controlling a hybrid system (1) according to claim 11, characterized in that the control logic determines a maximum allowable output power of the generator (106) as a function of the state of charge, the energy demand and the energy supply.

13. A method for controlling a hybrid system (1) according to claim 11 or 12, characterized in that the control logic for determining the change in state of charge takes into account the future energy needs of the vehicle, wherein the control logic can control the operation of the auxiliary consumers or regulate.

14. A method for controlling a hybrid system (1) according to any one of claims 11 to 13, characterized in that the control logic predicts the development of the waste heat of the internal combustion engine (110) and the development of the energy consumption of the secondary consumers.

15. A method of controlling a hybrid system according to claim 12, wherein the waste heat recovery system comprises a bypass line connected in parallel with the expansion machine, wherein a bypass valve controls the mass flow of the working medium into the expansion machine (104) and into the bypass line (108a),

characterized in that the control logic when exceeding the maximum allowable output power, the bypass valve (108) controls so that the mass flow of the working medium is reduced in the expansion machine (104).

16. A method for controlling a hybrid system according to claim 12, wherein the waste heat recovery system comprises an exhaust bypass connected in parallel with the evaporator, wherein an exhaust by-pass valve covers the exhaust gas mass flow of the internal combustion engine (110) into the evaporator (103) and into the exhaust gas bypass (113), characterized in that the control logic when exceeding the maximum allowable output power, the exhaust gas bypass valve (114) controls so that the exhaust gas mass flow into the evaporator (103) is reduced.