Method for heating the interior of a motor vehicle and motor vehicle

Abstract

Method for heating the interior of a motor vehicle with a turbocharged internal combustion engine (10), in which the waste heat of the turbocharged internal combustion engine (10) is used for interior heating, wherein at least temporarily the turbocharged internal combustion engine (10) is operated in an operating state with a higher generation of waste heat for interior heating compared to an efficiency-optimal operation, characterized in that the turbocharger is operated in a non-efficiency-optimal operating point, and that the turbocharger has a bypass line, wherein a mass flow through the bypass line is controllable or adjustable, and that a mass flow greater than an efficiency-optimal mass flow passes through the bypass line.

Description

[0001] The invention relates to a method for heating an interior of a motor vehicle having the features according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle having the features according to the preamble of claim 9.

[0002] When the ambient temperature is low, people using a motor vehicle expect the interior to be heated to a desired temperature as quickly as possible so that their stay in the vehicle is perceived as comfortable. A key energy source for heating is the waste heat from the motor vehicle's drive engine, which is often an internal combustion engine. In situations where the drive engine is started from cold or is operated with low power output, there is often little waste heat available to heat the interior. This fact is exacerbated in modern internal combustion engines by the fact that the internal combustion engine itself must first be heated to a certain operating temperature as quickly as possible in order to achieve the most efficient operation possible, particularly with minimal pollutant emissions.This need may require people to wait until the engine has reached a higher temperature before the interior is heated or becomes warm.

[0003] Auxiliary heating systems, whether electric or powered by an internal combustion engine, are therefore very common, and these disadvantageously require space in the vehicle. Furthermore, diesel engines also use combustion processes that accept a reduction in the diesel engine's efficiency in order to generate more waste heat. However, it has been found, especially with regard to auxiliary heating systems, that these solutions are often expensive and usually have a performance that is considered too low.

[0004] Document WO 2003 / 048548 A1 describes an improvement in heating the interior of a motor vehicle by operating the motor vehicle's internal combustion engine with partially deactivated cylinders. This results in more waste heat being produced in the still-operating cylinders due to the work performed and a reduction in the fresh air flowing through the internal combustion engine. This feeds additional energy into the engine's cooling system, which, among other things, heats the interior. The cylinders are deactivated using a variable valve train that can activate or deactivate cylinder valves.

[0005] Document WO 2003 / 048 548 A1 also points out that increasing the operating temperature of an internal combustion engine can also be achieved in various other ways: providing a valve in the exhaust system to reduce additional air flow, throttling the intake fresh gas, increasing the mass flow of recirculated exhaust gas, changing the injection timing or changing the valve opening or closing timing.

[0006] Furthermore, it is known from document DE 10 2012 217 714 A1 to open a valve of a compressor or turbine bypass of the turbocharger for the purpose of reducing noise from a turbocharger during a cold start.

[0007] The published patent application DE 10 2010 044 923 A1 describes a heating method for a motor vehicle with an internal combustion engine which has a supercharging and charge gas cooling as well as a low-pressure exhaust gas recirculation, and in which the fuel consumption of the internal combustion engine is artificially increased at least temporarily by the engine control unit by controlling the valves of an “exhaust gas recirculation” system when the cabin heating requirement is increased.

[0008] The published patent application DE 10 2009 042 745 A1 describes a cooling and heating circuit for motor vehicles with a coolant-cooled internal combustion engine with high charging potential and charge air cooling, in which coolant is pumped from a coolant pump to the heating heat exchanger for the cabin and finally back to the internal combustion engine, and in which, when the cabin heating power requirement increases, the fuel consumption of the internal combustion engine is artificially increased by adjusting devices influenced by the engine control system to vary the combustion process within the internal combustion engine.

[0009] The object of the present invention is to enable rapid heating of an interior of a motor vehicle, in particular during a cold start of the internal combustion engine of the motor vehicle.

[0010] This object is achieved according to the invention by a method for heating an interior of a motor vehicle having the features according to claim 1. Advantageous developments of the invention are characterized in the dependent claims.

[0011] In the method according to the invention for heating the interior of a motor vehicle with a supercharged internal combustion engine with a turbocharger, in which the waste heat of the supercharged internal combustion engine is used for interior heating, at least the following step is performed: At least temporarily, the supercharged internal combustion engine is operated in an operating state with a higher generation of waste heat for interior heating compared to an efficient operation. The turbocharger is operated at a non-efficient operating point.

[0012] In other words, according to the invention, the operating point of a turbocharger of a superchargeable internal combustion engine of a motor vehicle is selected with reduced efficiency compared to the optimum as a function of the heating power required, for example, by a person using the motor vehicle.

[0013] Advantageously, an additional heating device is no longer required: The inventive approach can be implemented solely by controlling the turbocharged internal combustion engine, for example, as software. It is therefore cost-effective and / or can be implemented with minimal manufacturing effort.

[0014] For the purposes of this presentation, the term "efficiency-optimal operating point" means that the turbocharged internal combustion engine is operated under conditions and / or with a parameter value and / or settings at an operating point in which the highest possible efficiency, preferably a substantially maximum efficiency, in particular the maximum efficiency, exists from the absorbed power (from the exothermic reaction of combustion) to the desired power output, in particular for the drive. A condition, a parameter value, or a setting can also be described as "efficiency-optimal" if it contributes to the efficiency-optimal operating point of the internal combustion engine.

[0015] Preferably, a cold start condition for the turbocharged internal combustion engine exists at least partially during use of the method according to the invention. During a cold start, the turbocharged internal combustion engine does not (yet) have reached its appropriate, in particular efficiency-optimal, operating temperature, but is essentially at ambient temperature. The interior is preferably an interior in which people using the motor vehicle are present. The turbocharged internal combustion engine can be a compression-ignition or spark-ignition internal combustion engine.

[0016] In operating situations where rapid warm-up of the turbocharger and subsequently the passenger compartment is desired, the turbocharger is not operated at optimal efficiency according to the invention. Such an adjustment, in particular control or regulation, of the turbocharger can advantageously be performed whenever the torque demand on the turbocharger does not permit the turbocharger to operate at optimal efficiency.

[0017] In a first group of embodiments, the method according to the invention is carried out in a turbocharged internal combustion engine whose turbocharger has a variable turbine geometry. The turbine geometry is then set to a position that is not optimal for efficiency. As a result, the turbocharged internal combustion engine does not reach its optimal operating point and is less efficient.

[0018] In a second group of embodiments, the method according to the invention is carried out in a superchargeable internal combustion engine whose turbocharger has a bypass line, wherein a mass flow flowing through the bypass line is controllable or regulatable. A mass flow that is smaller or (preferably) larger than an efficiency-optimized mass flow then flows through the bypass line. The bypass line can be opened in an operating state so that the optimal boost pressure for this operating state is not reached. The compressor of the turbocharger is then driven less, so that the superchargeable internal combustion engine operates at a lower efficiency. Alternatively, the engine can be operated in a less efficient operating state by a wider or completely closed bypass line than with a wider open bypass line. In particular, the bypass line can be maximally open.The bypass line can be opened before the maximum boost pressure for the operating condition is reached. The turbocharger's compressor is then not driven, so the turbocharged internal combustion engine operates in pure aspirated mode with lower efficiency.

[0019] It is particularly advantageous if, in the method according to the invention for heating the interior of a motor vehicle, the torque delivered by the turbocharged internal combustion engine is essentially the torque during efficient operation. In this case, the modified control of the turbocharger is essentially imperceptible to a person using the motor vehicle.

[0020] It is preferred for the method according to the invention that the interior heating is controllable or regulatable by means of a controller. The controller receives a heating output request, in particular as a function of an input from a person using the motor vehicle. The non-efficiency-optimal operating point of the turbocharger is (subsequently) set as a function of the heating output request. Various parameter profiles for the heating output request can preferably be set and executed by means of the controller or regulating system. In particular, there can be at least one profile for a comfortable heating output of the interior, which uses the method according to the invention, and one profile for an efficiency-optimized heating output. A switching element can be provided for a person using the motor vehicle, by means of which switching can be made between the available profiles.

[0021] To easily and / or conveniently indicate the special operation according to the method for heating an interior to a person using the motor vehicle, developments of the method according to the invention provide that, depending on the operation of the turbocharger at a non-optimal efficiency operating point, a signal is generated for perception by a person using the motor vehicle and emitted into the interior of the motor vehicle. The signal can, in particular, be an acoustic or optical signal, for example, the display of a visible symbol or text on a display element or an emitted signal tone. The display element can, in particular, be self-illuminating.

[0022] In specific embodiments of the method according to the invention, a variable that represents a measure of the interior temperature or a measure of the temperature of the turbocharged internal combustion engine, for example, the measured interior temperature, is monitored. After a threshold for the variable is exceeded, for example, if a predetermined target value for the interior temperature is exceeded, the non-efficient operation of the turbocharger is terminated.

[0023] The method according to the invention obviously leads to a changed, in particular reduced, boost pressure of the supercharged internal combustion engine. To counteract the perception of reduced power output from the supercharged internal combustion engine by a person using the motor vehicle, the method according to the invention can additionally provide for the changed boost pressure of the supercharged internal combustion engine compared to the efficient operation to be substantially compensated by a counteracting change in the air supply and / or the charge and / or the quantity of fuel supplied.

[0024] Another further development of the method according to the invention concerns at least partial automation of the control system: The turbocharger can only be operated at a non-optimal efficiency operating point if a variable representing the temperature of the turbocharged internal combustion engine lies within a predetermined value range. For example, the predetermined value range can be a temperature range in which a cold-start condition for the turbocharged internal combustion engine is met.

[0025] The inventive concept also relates to a motor vehicle with an interior, a rechargeable internal combustion engine, and a controller comprising at least one computer and a memory element. In the motor vehicle according to the invention, a program is stored in the memory element which, when at least partially executed in the computer with the aid of the rechargeable internal combustion engine, carries out a method according to the invention for heating the interior with features or combinations of features according to this description.

[0026] The motor vehicle according to the invention is preferably a railless and / or chainless land vehicle, in particular a passenger car or a commercial vehicle.

[0027] Further advantages and advantageous embodiments and developments of the invention are presented in the following description with reference to the figures. In detail: Fig. 1 a schematic representation of an embodiment of a superchargeable internal combustion engine with a control which allows the implementation of the method according to the invention, and Fig. 2 the topology of an advantageous embodiment of the links of the control elements for carrying out the method according to the invention.

[0028] The Fig. 1 schematically illustrates an embodiment of a superchargeable internal combustion engine 10 with a control system that allows the implementation of the method according to the invention. The superchargeable internal combustion engine 10 comprises a four-cylinder engine 12 that is supercharged by means of a turbocharger. A compressor 16 is located in the fresh gas line 14, and a turbine 20 of the turbocharger is located in the exhaust line 18. The turbine 20 is operatively connected to the compressor 16 to drive it. The turbine 20 has a variable geometry, i.e., the flow to the turbine 20 is changeable or variable by changing the positions of guide vanes, in particular by pivoting them. The turbine 20 is typically brought into the state for optimal efficiency by adjusting the variable geometry, so that the engine meets the torque requirement with minimal fuel consumption.

[0029] The turbine 20, more specifically the variable geometry actuator, is controlled by an engine control unit 22. The engine control unit 22 has a signal connection to an engine temperature sensor 24 and an outside temperature sensor 26. Furthermore, the engine control unit 22 is linked to an air conditioning control unit 28.

[0030] If the air conditioning is in heating mode, according to the invention the air conditioning control unit 28 sends a heating request to the engine control unit 22. The engine temperature sensor 24 determines whether the cooling water temperature of the engine 12 is below a predetermined switch-on threshold, for example below 70 degrees Celsius (example of a cold start condition). If this is the case, according to the invention the turbocharger is operated at a non-efficient operating point, so that compared to efficient operation more waste heat is initially generated for heating the engine 12 and thus for heating the interior. The amount of waste heat made available for heating the interior can depend on the outside temperature, which is measured in particular by the outside temperature sensor 26 and processed in the engine control unit 22.As soon as the cooling water temperature or alternatively the interior temperature reaches a predetermined switch-off threshold, in particular identical to the predetermined switch-on threshold, for example at 70 degrees Celsius, the heating operation according to the invention is switched off.

[0031] The turbocharged internal combustion engine 10, along with the control system, is arranged in a motor vehicle's engine compartment (not shown in the drawing). The motor vehicle (not shown in the drawing) has an interior designed specifically for passenger transportation. The waste heat generated by the engine 12 is used at least partially to heat a medium for interior heating. Waste heat absorbed from the cooling water of the engine 12 is passed through a heat exchanger to heat the medium. The medium can, in particular, be the air supplied to the interior.

[0032] The climate control unit is used to control or regulate the air conditioning, particularly the temperature of the interior of the motor vehicle. For this purpose, the interior contains a plurality of controllable or adjustable air outlet elements and, if appropriate, at least one temperature sensor. They serve as a source of tempered air for the interior, with the temperature depending, among other things, on the position of a mixed air flap located upstream of the air outlet elements. The temperature can be adjusted by changing the position of the mixed air flap.

[0033] The Fig.Figure 2 shows the topology of an advantageous embodiment of the control element connections for implementing the method according to the invention. For the advantageous implementation of the method according to the invention, the engine control unit 22 receives, on the one hand, signals from various sensors 30 for the turbocharged internal combustion engine and, on the other hand, signals from the climate control unit 28. In addition to the engine temperature sensor 24 and the outside temperature sensor 26, other measured variables of the internal combustion engine are advantageously taken into account: For this purpose, the signals from a sensor 32 for the (at least partially modeled) exhaust gas temperature, a sensor 34 for the torque demand, and a sensor 36 for the vehicle speed are received and processed by the engine control unit 22.

[0034] The engine control unit 22 receives signals from the climate control unit 28 regarding the heating request 38 specified by a person using the vehicle's interior and regarding the position of the mixed air flap 40. The received information is processed in the engine control unit 22. A control signal for the turbine actuator 42 is generated and transmitted to the turbine actuator 42. In the case of a turbine 20 with variable geometry, the turbine actuator 42 is an actuator for changing the turbine flow. In the case of a turbine 20 with a bypass line (wastegate), the turbine actuator 42 is an actuator for the bypass line valve.

[0035] In heating mode according to the invention, a torque of the internal combustion engine is generated with an increased use of fuel, in particular a maximum use of fuel under the boundary conditions to be observed, such as torque neutrality, in order to produce as much waste heat as possible. In turbochargers, this can be achieved in particular by a high exhaust gas backpressure. For turbines 20 with variable geometry, the cross-section of the exhaust gas flow towards the turbine is reduced for this purpose by adjusting the guide vanes. This increases the speed of the turbine. The consequently increased boost pressure is compensated for in a spark-ignition internal combustion engine by a throttled air supply and in a compression-ignition internal combustion engine by a reduced fuel injection quantity. List of reference symbols 10 rechargeable internal combustion engines 12 Engine 14 Fresh gas system 16 compressors 18 Exhaust system 20 turbines 22 Engine control unit 24 Engine temperature sensor 26 Outside temperature sensor 28 Climate control unit 30 sensors for internal combustion engines 32 Exhaust gas temperature sensor 34 Torque request sensor 36 Vehicle speed sensor 38 Heating power requirement 40 Position mixed air flap 42 turbine actuators

Claims

[1] Method for heating an interior of a motor vehicle with a superchargeable internal combustion engine (10) with a turbocharger, in which the waste heat of the superchargeable internal combustion engine (10) is used for heating the interior, wherein at least temporarily the superchargeable internal combustion engine (10) is operated in an operating state with a higher generation of waste heat for heating the interior compared to an efficient operation, characterized by that the turbocharger is operated at a non-efficiency-optimal operating point, and that the turbocharger has a bypass line, wherein a mass flow flowing through the bypass line is controllable or regulatable, and that a mass flow which is greater than an efficiency-optimal mass flow flows through the bypass line. [2] Method for heating an interior of a motor vehicle according to claim 1, characterized bythat the turbocharger has a variable turbine geometry and that the turbine geometry is placed in a position that is not optimal for efficiency. [3] Method for heating an interior of a motor vehicle according to claim 1, characterized by that the torque delivered by the superchargeable internal combustion engine (10) is essentially the torque in efficiency-optimal operation. [4] Method for heating an interior of a motor vehicle according to claim 1, characterized by that the interior heating can be controlled or regulated by means of a control, that the control receives a heating power request (38) and that the non-efficiency-optimal operating point of the turbocharger is set as a function of the heating power request (38). [5] Method for heating an interior of a motor vehicle according to claim 1, characterized bythat, as a function of the operation of the turbocharger at a non-efficient operating point, a signal is generated for perception by a person and emitted into the interior of the motor vehicle. [6] Method for heating an interior of a motor vehicle according to claim 1, characterized by that a variable which represents a measure of the interior temperature or a measure of the temperature of the superchargeable internal combustion engine (10) is monitored and, after passing a threshold for the measure, the non-efficient operation of the turbocharger is terminated. [7] Method for heating an interior of a motor vehicle according to claim 1, characterized by that the change in the boost pressure of the superchargeable internal combustion engine (10) compared to the efficiency-optimal operation is substantially compensated by a counteracting change in the air supply and / or the filling and / or the quantity of fuel supplied. [8] Method for heating an interior of a motor vehicle according to claim 1, characterized by that the turbocharger is only operated at a non-efficient operating point, provided that a variable which represents a measure of the temperature of the superchargeable internal combustion engine (10) lies within a predetermined value range. [9] Motor vehicle with an interior, a rechargeable internal combustion engine (10) and a control system which comprises at least one computer and one memory element, characterized by that a program is stored in the memory element which, when at least partially executed in the computer with the aid of the rechargeable internal combustion engine, carries out a method for heating the interior according to one of the preceding claims.

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