Method for heating a passenger compartment of a vehicle

Abstract

Method for heating a passenger compartment of a vehicle (10) wherein the method comprises: Increasing the temperature of a coolant in a coolant circuit (230) comprising a heating heat exchanger (244) by supplying an electric current to a heating device with a positive temperature coefficient (265) in response to an ambient temperature lower than a threshold temperature, and Increasing the temperature of the coolant using heat transferred by a heat pump (232) in response to an ambient temperature higher than the threshold temperature, wherein the heating device with a positive temperature coefficient (265) is arranged in an intermediate heat exchanger (242), and wherein the heat pump (232) contains a compressor (260).

Description

Area

[0001] The present invention relates to methods for improving the heating of a vehicle. These methods can be particularly useful in vehicles that are exclusively electrically powered, or in vehicles that may have an engine which can be stopped during operation to improve hydrocarbon fuel savings. Background and brief description

[0002] Methods for heating vehicles are disclosed in WO 2012 / 144 151 A1 and JP 2008-94 366 A. A vehicle's passenger compartment can be heated by an engine at low ambient temperatures. However, some hybrid vehicles can be operated temporarily without starting the engine to save hydrocarbon fuel. For such vehicles, it may be desirable to provide an alternative method for heating the passenger compartment. One way to heat a passenger compartment without starting an engine is to supply heat to the passenger compartment using a heat pump. The heat pump extracts heat from the ambient environment to heat the passenger compartment. Heat pumps are effective at some temperatures, but their efficiency can decrease at lower temperatures. Therefore, it may be desirable to heat a vehicle's passenger compartment using a different device.

[0003] The inventor of the present invention has recognized the aforementioned disadvantages and has developed a method for heating a passenger compartment of a vehicle, comprising: increasing the temperature of a coolant in a coolant circuit having a heating heat exchanger by supplying electric current to a positive temperature coefficient heater (PTC heater) in response to an ambient temperature lower than a threshold temperature, and increasing the temperature of the coolant by means of heat transferred by a heat pump in response to an ambient temperature higher than the threshold temperature, wherein the positive temperature coefficient heater is arranged in an intermediate heat exchanger, and wherein the heat pump includes a compressor.

[0004] By heating the coolant using a PTC heater and / or a heat pump, it is possible to achieve the same result as heating a vehicle's passenger compartment across a wide range of ambient temperatures. Furthermore, because the coolant is heated by the PTC heater and heat pump, numerous components of a non-hybrid vehicle can also be used in a hybrid or electric vehicle. For example, a passenger compartment ventilation system can be used in both hybrid and non-hybrid vehicles, as coolant is the heat transfer medium in both types of vehicles. Additionally, an engine can be heated using PTC heaters, thus reducing engine emissions and fuel consumption.

[0005] The present description can offer several advantages. In particular, the approach can improve the heating of the passenger compartment in electric and hybrid vehicles. Furthermore, the approach can reduce fuel consumption and vehicle emissions by heating the engine using the vehicle's kinetic energy. In addition, the approach can improve the range of an electric vehicle by reducing the charge consumed by the battery for heating the passenger compartment.

[0006] The aforementioned advantages, as well as other advantages and features of the present description, can easily be seen from the following detailed description, whether taken alone or in conjunction with the accompanying drawings.

[0007] It should be noted that the foregoing summary is intended to introduce, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to identify principal or essential features of the claimed subject matter, the scope of which is clearly defined by the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that solve any of the problems identified above or in any part of this disclosure. Brief description of the drawings

[0008] The advantages described here can be more fully understood by reading an example of an embodiment, referred to here as the detailed description, either individually or with reference to the drawings, wherein: Fig. 1 is a schematic diagram of a vehicle; Fig. 2 an exemplary vehicle heating system for the vehicle made of Fig. 1 shows; Fig. 3 an exemplary vehicle powertrain for the vehicle made of Fig. 1 shows; Fig. 4 shows a method for operating a heating system and Fig. 5 a simulated example sequence for operating a vehicle heating system according to the procedure from Fig. 4 shows. Detailed description

[0009] The present description concerns the provision of heat to a vehicle. In particular, a vehicle's coolant circuit can be heated to warm a passenger compartment and / or an engine when the engine is not running. The vehicle can be a passenger car, such as in Fig. 1 shown, or it could be a commercial vehicle (not shown). The vehicle has a climate control system, as shown in Fig. 2 shown. The climate control system may include a motor that is part of a hybrid powertrain, as shown in Fig. 3 shown. The vehicle can be identified based on the procedure from Fig. 4. The vehicle can be supplied with heat, as shown in the operating sequence from Fig. 5 shown, according to the procedure from Fig. 4 are heated.

[0010] With reference to Fig. Figure 1: A vehicle 10 is shown, equipped with an engine (internal combustion engine) 12, an electric machine, and an electrical energy storage device 11. In one example, the vehicle can be powered exclusively by the engine 12, exclusively by the electric machine 14, or by both the engine 12 and the electric machine 14. Electrical power can be supplied to the electric machine by means of the electrical energy storage device 11. The electrical energy storage device 11 can be recharged by the engine 12 supplying power to the electric machine 14, and the electric machine supplying electrical energy to the electrical energy storage device 11.Alternatively, the electrical energy storage device can be recharged by converting the vehicle's kinetic energy into electrical energy using the electric machine 14 during deceleration or downhill driving. The electrical energy storage device 11 can also be recharged from a stationary power grid using a home charging system or a remote charging system (e.g., a charging station). In one example, the electrical energy storage device 11 is a battery. Alternatively, the electrical energy storage device 11 could be a capacitor or another type of storage device.

[0011] Fig. Figure 2 shows a vehicle heating system or a climate control system 224. Devices and fluidic channels or lines are shown as solid lines. Electrical connections are shown as dashed lines.

[0012] Vehicle 10 can have a powertrain like the one in Fig. 3 or another suitable powertrain to propel the vehicle 10 and / or supply energy to vehicle components. The vehicle 10 is shown with an internal engine, such as an internal combustion engine 12, and it can be selectively coupled to an electric machine (not shown). The internal combustion engine 12 can burn gasoline, diesel, alcohol, hydrogen, or a combination of fuels.

[0013] The vehicle 10 can have a passenger compartment 220, an engine compartment 222, and a climate control system 224. The passenger compartment 220 can be located within the vehicle 10 and can accommodate one or more occupants. A section of the climate control system 224 can be located within the passenger compartment 220.

[0014] The engine compartment 222 can be located near the passenger compartment 220. One or more energy sources, such as the internal combustion engine 12, as well as a section of the climate control system 224, can be located in the engine compartment 222. The engine compartment 222 can be separated from the passenger compartment 220 by a bulkhead 226. The climate control system 224 can circulate air and / or regulate or change the temperature of air circulating in the passenger compartment 220. Furthermore, the internal combustion engine 12 can be heated using the climate control system 224 to reduce fuel consumption and emissions. The climate control system 224 can include a coolant subsystem (coolant circuit) 230, a heat pump 232, and a ventilation subsystem 234.

[0015] A coolant such as glycol can circulate via the coolant subsystem 230, which can also be referred to as a coolant circuit, to cool the internal combustion engine 12. For example, waste heat generated by the internal combustion engine 12 when the engine is running or ready for operation can be transferred to the coolant and subsequently circulate to the radiator 231 to cool the internal combustion engine 12. In at least one example, the coolant subsystem 230 can include a coolant pump 240, an intermediate heat exchanger 242, an electrically activated positive temperature coefficient (PTC) heater 265 integrated into and immersed in the coolant within the intermediate heat exchanger 242, a heater 244, and a bypass circuit 248, all of which are interconnected by means of lines or channels such as tubes, hoses, pipes, or the like.The coolant subsystem 230 includes a radiator 231 for transferring heat energy to the ambient air surrounding the vehicle 10. The coolant subsystem 230 also includes electrically operated valves, a bypass circuit control valve 250 and a valve 251, for adjusting the coolant flow through the internal combustion engine 12, the radiator 231, and the intermediate heat exchanger 242. The electrically operated valves 250 and 251 are selectively controlled by the control unit 212.

[0016] The coolant pump 240 circulates coolant through the coolant subsystem 230. The coolant pump 240 can be powered by an electrical or non-electrical energy source. For example, the coolant pump 240 can be operationally coupled to an internal combustion engine 12 by means of a belt, or alternatively, it can be driven by an electrically driven motor. The coolant pump 240 can receive coolant from the internal combustion engine 12 and circulate the coolant in a closed circuit. For example, if the climate control system 224 is in heating mode, coolant can be directed by the coolant pump 240, bypassing the radiator 231, to the intermediate heat exchanger 242 and then to the heater core 244 before flowing back to the internal combustion engine 12, as indicated by the arrows.When the internal combustion engine 12 emits a higher level of heat energy, coolant can flow from the coolant pump 240 to the radiator 231 before flowing back to the internal combustion engine 12 via the intermediate heat exchanger 242 and the heater core 244. The electrically operated valve 251 directs coolant from the coolant pump 240 through or around the radiator 231 and to the electrically operated valve 250. Based on the position of the electrically operated valve 250, coolant can flow through or around the internal combustion engine 12.

[0017] The intermediate heat exchanger 242 facilitates the transfer of thermal energy between the coolant subsystem 230 and the heat pump 232. Specifically, heat can be transferred from the heat pump 232 to the coolant subsystem 230. The intermediate heat exchanger 242 can be part of both the coolant subsystem 230 and the heat pump 232. The intermediate heat exchanger 242 can have any suitable configuration. For example, the intermediate heat exchanger 242 can have a plate-fin, tube-fin, or tube-and-shell configuration, which facilitates the transfer of thermal energy from the heat pump 232 to the coolant subsystem 230 without mixing or exchanging the heat transfer fluids in the coolant subsystem 230 and the heat pump 232.Heat can be transferred from the heat pump 232 to the coolant via the intermediate heat exchanger 242 when the climate control system 224 is in heating mode. The intermediate heat exchanger 242 has an integrated electrically operated positive temperature coefficient (PTC) heater 265. The PTC heater can be activated by the control unit 212 in response to a request to heat the passenger compartment 220 and / or a request to heat the internal combustion engine 12.

[0018] The heating heat exchanger 244 allows heat energy to be transferred from the coolant to the air in the passenger compartment 220. The heating heat exchanger 244 can be located in the passenger compartment 220 within the ventilation subsystem 234 and can have any suitable configuration. For example, the heating heat exchanger 244 can have a finned plate or finned tube design in one or more examples.

[0019] The bypass circuit 248 allows coolant to be routed in such a way that it is not heated by the internal combustion engine 12. A bypass circuit control valve 250 regulates the flow of coolant through the bypass circuit 248. More precisely, when in its first position, the bypass circuit control valve 250 allows coolant to flow through a bypass line 252 while blocking the flow of coolant from the internal combustion engine 12 to the intermediate heat exchanger 242. In this position, a second coolant pump 254 circulates coolant through the bypass circuit 248, from the intermediate heat exchanger 242 to the heater core 244, back to the bypass line 252, and then back to the second coolant pump 254.Therefore, the coolant in the coolant subsystem 230 can be heated by the heat pump 232 through the intermediate heat exchanger 242 or the PTC heaters 265, or, in some operating modes, independently by the intermediate heat exchanger 242 and the PTC heaters 265. The bypass circuit control valve 250 may also block the flow of coolant through the bypass line 252 when it is in a second position. The second coolant pump 254 can circulate coolant or not, depending on whether coolant is flowing through the bypass line 252.

[0020] The heat pump 232 can transfer thermal energy to or from the passenger compartment 220 and to or from the coolant subsystem 230. In at least one example, the heat pump 232 can be configured as a compression heat pump subsystem in which a fluid circulates through the heat pump 232 to transfer thermal energy to or from the passenger compartment 220. The heat pump 232 can operate in various modes, including, but not limited to, a cooling mode and a heating mode. In cooling mode, the heat pump 232 can circulate a heat transfer fluid, which can be referred to as a refrigerant, to transfer thermal energy from inside the passenger compartment 220 to outside the passenger compartment 220. In heating mode, the heat pump 232 can transfer thermal energy from the refrigerant to the coolant using the intermediate heat exchanger 242, without the refrigerant circulating through a heat exchanger in the passenger compartment 220.

[0021] In heating mode, the heat pump 232 can have a pump 260, which can also be called a compressor, a first control valve 262, a first expansion device 264, an external heat exchanger 266, a second control valve 268, a third control valve 270, a storage tank 272, a second expansion device 274, an internal heat exchanger 276, and an optional internal heat exchanger 278. Components of the heat pump 232 can be interconnected via one or more lines, such as a pipe, a hose, or the like. Fig. 2 shows the refrigerant circulation path in heating mode, represented by the arrow lines.

[0022] The pump 260, which can also be called a compressor, pressurizes the refrigerant and circulates it through the heat pump 232. The pump 260 can be powered by an electrical or non-electrical energy source. For example, the pump 260 can be operationally coupled to the internal combustion engine 12 or driven by an electrically driven motor. In heating mode, the pump 260 can supply the intermediate heat exchanger 242 with high-pressure refrigerant, which in turn can transfer heat from the high-pressure refrigerant to a coolant flowing through the intermediate heat exchanger 242 to heat the coolant flowing in the coolant subsystem 230.

[0023] The first control valve 262 can be arranged along a bypass path 280, which may be located between the intermediate heat exchanger 242 and the first expansion device 264. The bypass path 280 allows some refrigerant to bypass the first expansion device 264 and the outer heat exchanger 266 and flow to the internal heat exchanger 278 (if present), the second expansion device 274, and the inner heat exchanger 276 when the first control valve 262 is open. In heating mode, the first control valve 262 can be closed to block the flow of refrigerant through the bypass path 280 to the inner heat exchanger 276.

[0024] The first expansion device 264 can be arranged between the intermediate heat exchanger 242 and the outer heat exchanger 266 and be flow-connected to them. The first expansion device 264 can be designed to change the pressure of the refrigerant. For example, the first expansion device 264 can be a thermal expansion valve (TXV) or a fixed or variable-position valve that can be controlled externally. The pressure of the refrigerant flowing from the intermediate heat exchanger 242 through the first expansion device 264 to the outer heat exchanger 266 can be reduced by means of the first expansion device 264. Therefore, in heating mode, the high-pressure refrigerant received from the intermediate heat exchanger 242 can exit the first expansion device 264 at a lower pressure and as a liquid-vapor mixture.

[0025] The external heat exchanger 266 can be located outside the passenger compartment 220. In a cooling mode or air conditioning context, the external heat exchanger 266 can act as a condenser and transfer heat to the surrounding environment to condense the refrigerant from a vapor to a liquid. In a heating mode, the external heat exchanger 266 can act as an evaporator and transfer heat from the surrounding environment to the refrigerant, causing it to evaporate.

[0026] The second control valve 268 can be located between the external heat exchanger 266 and the bypass path 280. The second control valve 268 can be a shut-off valve, and it can block the flow of refrigerant from the bypass path 280 to the external heat exchanger 266. Therefore, refrigerant escaping from the external heat exchanger 266 when the climate control system 224 is in heating mode can be directed to the third control valve 270.

[0027] A third control valve 270 can be arranged between the external heat exchanger 266 and the storage tank 272. The third control valve 270 helps to regulate the flow of refrigerant exiting the external heat exchanger 266. In heating mode, the third control valve 270 can be open to allow refrigerant to flow from the external heat exchanger 266 to the storage tank 272. In other modes, such as cooling mode, the third control valve 270 can be closed and the second expansion device 274 can be open.

[0028] Storage unit 272 can serve as a reservoir for storing any remaining liquid refrigerant, allowing pump 260 to be supplied with vaporous refrigerant instead of liquid. Storage unit 272 may contain a desiccant that absorbs small amounts of water vapor from the refrigerant.

[0029] The second expansion device 274 can be arranged between the outer heat exchanger 266 and the inner heat exchanger 276 and be fluidically connected to them. The second expansion device 274 can have a similar structure to the first expansion device 264 and can be configured to change the refrigerant pressure in a similar manner. Furthermore, the second expansion device 274 can be closed to block the refrigerant flow. More precisely, the second expansion device 274 can be closed to block the flow of refrigerant from the outer heat exchanger 266 to the inner heat exchanger 276 in heating mode. Therefore, closing the second expansion device 274 can block the flow of refrigerant through the second control valve 268 to the internal heat exchanger 278 (if present) and also through the inner heat exchanger 276.

[0030] The internal heat exchanger 276 can be fluidically connected to the second expansion device 274. The internal heat exchanger 276 can be located within the passenger compartment 220. In a cooling mode or air conditioning context, the internal heat exchanger 276 can act as an evaporator and absorb heat from the air in the passenger compartment 220 to evaporate the refrigerant. Refrigerant exiting the internal heat exchanger 276 can be directed to the reservoir 272. In heating mode, no refrigerant may be directed to the internal heat exchanger 276 due to the closed state of the second expansion device 274.

[0031] The internal heat exchanger 278, if present, can transfer thermal energy between refrigerants flowing through different sections of the heat pump 232. The internal heat exchanger 278 can be located outside the passenger compartment 220. In cooling mode or an air conditioning context, heat can be transferred from refrigerant flowing from the external heat exchanger 266 to the internal heat exchanger 276 to refrigerant flowing from the reservoir 272 to the pump 260. In heating mode, the internal heat exchanger 278 does not transfer thermal energy between such refrigerant flow paths because the second expansion device 274 is closed, thus blocking the flow of refrigerant through a section of the internal heat exchanger 278.

[0032] The ventilation subsystem 234 allows air to circulate in the passenger compartment 220 of the vehicle 10. The ventilation subsystem 234 can include a housing 290, a blower 292, and a temperature door 294.

[0033] The housing 290 can accommodate components of the ventilation subsystem 234. In Fig. Figure 2 illustrates the housing 290 such that internal components are visible for clarity. Furthermore, an airflow through the housing 290 and internal components are represented by the arrow lines 277. The housing 290 may be located, at least partially, within the passenger compartment 220. For example, the housing 290, or a section thereof, may be located beneath the dashboard of the vehicle 10. The housing 290 may have an air inlet section 200 that can draw in air from outside the vehicle 10 and / or air from within the passenger compartment 220. For example, the air inlet section 200 may draw in ambient air from outside the vehicle 10 via an intake duct, pipe, or opening, which may be located at any suitable location, such as near a cowl, wheel well, or other body panel of the vehicle.The air intake section 200 can also draw in air from inside the passenger compartment 220 and return such air through the ventilation subsystem 234. One or more flaps or air slots can be provided to allow or block the return of air.

[0034] The blower 292 can be arranged in the housing 290. The blower 292, which can also be referred to as a fan, can be located near the air inlet section 200 and can be configured as a radial fan, which helps to circulate air through the ventilation subsystem 234.

[0035] The temperature damper 294 can be arranged between the inner heat exchanger 276 and the heater heat exchanger 244. In the example shown, the temperature damper 294 is arranged downstream of the inner heat exchanger 276 and upstream of the heater heat exchanger 244. The temperature damper 294 can be used to block or allow airflow through the heater heat exchanger 244, thus helping to regulate the temperature of the air in the passenger compartment 220. For example, the temperature damper 294 can allow airflow through the heater heat exchanger 244 in heating mode, so that heat can be transferred from the coolant to the air flowing through the heater heat exchanger 244. This heated air can then be supplied to a plenum for distribution to ducts and air dampers or outlets located in the passenger compartment 220.The temperature damper 294 can be moved between a variety of positions to supply air at a desired temperature. Fig. Figure 2 shows the temperature flap 294 in a position at maximum heat, in which an airflow is directed through the heating heat exchanger 244.

[0036] The control unit 212 displays executable instructions for the procedure. Fig. 4 for operating the valves, fans and pumps or compressors of the in Fig. The system shown in Figure 2. The control unit 212 has inputs 201 and outputs 202 for connecting to devices in the system. Fig. 2. The control unit 212 also includes a central unit 205 and non-volatile memory 206 for executing the procedure. Fig. 4 up.

[0037] Fig. Figure 3 shows a block diagram of a vehicle powertrain 300 in the vehicle 10. The powertrain 300 can be driven by the engine 12. The engine 12 can be started using an engine starting system with a starter 301 or using the electric machine 14, which can be designed as a driveline integrated starter generator (DISG). Furthermore, the engine 12 can generate or adjust torque using a torque actuator 304, such as a fuel injector, throttle, camshaft, etc.

[0038] An engine output torque can be transmitted to a drivetrain disconnect clutch 305. The drivetrain disconnect clutch selectively engages or disengages the drivetrain 300. The drivetrain disconnect clutch 305 can be actuated electrically or hydraulically. The power side of the drivetrain disconnect clutch 305 is shown mechanically coupled to the DISG input shaft 303.

[0039] The machine (DISG) 14 can be operated to supply torque to the drivetrain 300 or to convert drivetrain torque into electrical energy for storage in the electrical energy storage device 11. The machine (DISG) 14 has a power output greater than that of the starter 301. Furthermore, the machine (DISG) 14 directly drives the drivetrain 300 or is directly driven by the drivetrain 300. There are no belts, gears, or chains to couple the DISG 14 to the drivetrain 300. Instead, the machine (DISG) 14 rotates at the same speed as the drivetrain 300. The electrical energy storage device 11 can be a battery, a capacitor, or an inductor. The power side of the machine (DISG) 14 is mechanically coupled to the transmission 308.

[0040] The automatic transmission 333 includes gear clutches (e.g., gears 1 to 6) for setting a gear ratio. The gear clutches can be selectively engaged to propel the vehicle 10. A torque output from the transmission 308 can, in turn, be transmitted to the wheels 316 to propel the vehicle by means of an output shaft 334. The output shaft 334 transmits torque from the transmission 308 to the wheels 316. The transmission 308 can transmit an input drive torque to the wheels 316.

[0041] Furthermore, the wheels 316 can be subjected to a frictional force by engaging wheel friction brakes 318. In one example, the wheel friction brakes 318 can be engaged in response to the driver pressing their foot on a brake pedal (not shown). In other examples, the control unit 212 or a control unit connected to the control unit 212 can engage the wheel friction brakes. In the same way, a frictional force acting on the wheels 316 can be reduced by releasing the wheel friction brakes 318 in response to the driver releasing their foot from a brake pedal. Additionally, vehicle brakes can apply a frictional force to the wheels 316 as part of an automated procedure for stopping the engine, using the control unit 212.

[0042] The control unit 212 can be programmed to receive inputs from the engine 12 and accordingly control the engine's torque output and / or the operation of the torque converter, transmission, automatic transmission (DISG), clutches, and / or brakes. For example, torque output can be controlled by adjusting a combination of ignition timing, fuel pulse width, fuel pulse timing, and / or air charge, using throttle opening and / or valve timing control, valve lift, and boost for turbocharged or supercharged engines. In the case of a diesel engine, the control unit 212 can control the engine's torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In any case, engine control per cylinder can be implemented to control the engine's torque output.The control unit 212 can also control torque output and the generation of electrical energy by the machine (DISG) by adjusting the current flowing to and from the DISG windings, as is known in the field.

[0043] If idle stop conditions are met, the control unit 212 can initiate engine shutdown by cutting off fuel and spark to the engine. However, in some cases, the engine may continue to turn over. Conversely, if restart conditions are met and / or a vehicle operator wishes to start the vehicle, the control unit 212 can reactivate the engine by resuming combustion in cylinders. The engine can be started by turning it over using the Disabled Gearbox (DISG) 14 or the starter 301.

[0044] In this way, the system is made up of Fig. 1, Fig. 2 to Fig. 3. A vehicle system is provided comprising: a coolant circuit with a positive temperature coefficient (PTC) heater immersed in a coolant, the coolant flowing through a heater core and a heat exchanger, and a heat pump incorporating the heater core. The vehicle system is characterized by the heater core being located in a passenger compartment. The vehicle system also comprises a control unit, the control unit having instructions stored in non-volatile memory for heating an engine using the PTC heater. The vehicle system also comprises further executable instructions stored in non-volatile memory for supplying heat to a passenger compartment. The vehicle system also comprises further executable instructions stored in non-volatile memory for heating the passenger compartment using the PTC heater.The vehicle system also includes an electric machine that supplies power to the PTC heating device during regenerative braking.

[0045] In Fig. Figure 4 shows a flowchart of a procedure for heating sections and / or components of a vehicle. The procedure from Fig. 4 can be executed as instructions in non-volatile memory in the system. Fig. 1, Fig. 2 to Fig. 3 are stored. Through the procedure from Fig. 4 can also be the one in Fig. The operating sequence shown in section 5 is provided. In some examples, the procedure is derived from... Fig. 4. This may only be called up if the ambient temperature is lower than a threshold temperature, thus saving electrical energy. Heat can be supplied to the passenger compartment using a heat pump, as in Fig. Figure 2 shows what happens when the ambient temperature is higher than the threshold temperature. Furthermore, heat can be supplied to the passenger compartment using the PTC heaters and the heat pump.

[0046] In procedure 402, procedure 400 determines whether a battery state of charge (SOC) greater than the first threshold charge (GA) is a threshold charge. The battery SOC can be determined by measuring a battery voltage and / or measuring current flow into and out of the battery. If procedure 400 determines that a battery SOC is greater than the first threshold SOC, the answer is "Yes," and procedure 400 proceeds to 420. Otherwise, the answer is "No," and procedure 400 proceeds to 404.

[0047] At step 420, procedure 400 decides whether heat is requested for the vehicle's passenger compartment. In one example, a request for passenger compartment heat might be made by an operator activating a climate control input device. In other examples, a request for passenger compartment heat might be made using a climate controller. If procedure 400 decides that there is a request for passenger compartment heat, the answer is "Yes," and procedure 400 proceeds to step 422. Otherwise, the answer is "No," and procedure 400 proceeds to the end.

[0048] In procedure 422, procedure 400 determines whether the engine is running and burning air and fuel. In one example, procedure 400 determines whether the engine is burning air and fuel based on whether it is receiving spark and fuel. If procedure 400 determines that the engine is running, the answer is "Yes," and procedure 400 proceeds to 426. Otherwise, the answer is "No," and procedure 400 proceeds to 424.

[0049] At 424, the procedure activates 400 PTC heaters in the intermediate heat exchanger 242 to heat coolant flowing in the coolant subsystem 230. Furthermore, when the engine is not running, the valve 250 is set to a position where coolant flows through the bypass line 252 and not through the internal combustion engine 12. However, when the engine is running, the valve 250 is set to a position where coolant exiting the engine is routed through the intermediate heat exchanger 242 and the heater core 244. Additionally, when the internal combustion engine 12 is burning air and fuel, the valve 251 is set to a position bypassing the radiator 231 to increase the heat held in coolant flowing to the heater core 244. Coolant heated by the PTC heating devices is directed to the heating heat exchanger 244 by means of activation of the pump 254.The blower 292 can also be activated to draw air from the passenger compartment through the heating heat exchanger 244, where the passenger compartment air is heated by heat exchanged between a coolant flowing through the heating heat exchanger 244 and the passenger compartment air. The flow of electrical current to PTC heaters can be controlled by feedback to set the coolant temperature to a desired temperature. Furthermore, the heat pump 232 can be activated by activating the pump 260 when the ambient temperature exceeds a threshold temperature, so that both the heat pump 232 and the PTC heater 265, via the intermediate heat exchanger 242, supply heat to the coolant and the passenger compartment.Furthermore, if an ambient temperature is higher than a second threshold ambient temperature, the current flow to the PTC heater 265 can be terminated, while the heat pump 232 remains in operation to improve the efficiency of the heat pump. In this way, the passenger compartment can be heated solely by the heat pump, solely by the PTC heater, or, if the engine is not running, by the PTC heater and the heat pump. Method 400 proceeds to completion after the air in the passenger compartment has been heated using a coolant, the heat pump, and / or the PTC heaters. It should be noted that installing PTC heaters in the intermediate heat exchanger 242 allows the PTC heater voltage and current to remain outside a passenger compartment 220. Furthermore, exposing the PTC heaters to a coolant instead of air allows a larger percentage of climate control components to be used in both electrically and non-electrically powered vehicles.

[0050] At 426, procedure 400 determines whether an engine temperature is higher than a first threshold temperature. The engine temperature could be a cylinder head temperature, engine coolant temperature, or another engine temperature. The first threshold engine temperature can be lower than a warm, stabilized operating temperature for the engine (e.g., 90°C). For example, the first threshold engine temperature could be 20°C. If procedure 400 determines that an engine temperature is higher than the first threshold temperature, the answer is "Yes," and procedure 400 proceeds to 428. Otherwise, the answer is "No," and procedure 400 proceeds to 424.

[0051] At 428, procedure 400 determines whether the engine temperature is higher than a second threshold temperature. The engine temperature can be a cylinder head temperature, an engine coolant temperature, or another engine temperature. The second threshold engine temperature can be slightly lower than a warm, stabilized operating temperature for the engine. For example, the first threshold engine temperature can be 65°C. If procedure 400 determines that an engine temperature is higher than the second threshold temperature, the answer is "Yes," and procedure 400 proceeds to 432. Otherwise, the answer is "No," and procedure 400 proceeds to 430.

[0052] At step 430, the procedure activates 400 PTC heaters in the intermediate heat exchanger 242 to heat the coolant flowing in the coolant subsystem 230. Additionally, the heater core 244 is supplied with heat from the engine. Specifically, valve 250 is set to a position in which coolant exiting the engine is routed through the intermediate heat exchanger 242 and the heater core 244, and no coolant flows through the bypass line 252. Furthermore, valve 251 is set to a position so that coolant exiting the engine bypasses radiator 231 to increase the heat retained in the coolant flowing to the heater core 244. Coolant heated by the PTC heaters is then directed to the heater core 244 by activating pump 254. Therefore, the motor and the PTC heating devices supply heat to the heating heat exchanger 244.The blower 292 can also be activated to draw air from the passenger compartment through the heater heat exchanger 244, where the passenger compartment air is heated by heat exchanged between a coolant flowing through the heater heat exchanger 244 and the passenger compartment air. The flow of electrical current to PTC heaters can be controlled by feedback to set the coolant temperature to a desired temperature. The process 400 proceeds to completion after the air in the passenger compartment has been heated by a coolant heated by the motor and the PTC heaters.

[0053] Furthermore, the 400 procedure at 430 can determine whether an ambient temperature is higher than a threshold temperature. If so, the heat pump section of the system delivers... Fig. 2. Heat is transferred to the coolant flowing to the heating heat exchanger while the PTC heaters are deactivated. The heat pump can be more efficient at heating a coolant than the PTC heaters when the ambient temperature is higher than a threshold temperature. However, when the ambient temperature is lower than the threshold temperature, the PTC heaters are activated, and the heat pump is deactivated. In this way, coolant in the coolant circuit can be heated using either the PTC heaters or the heat pump 232.

[0054] In vehicle 432, method 400 provides heat for the passenger compartment exclusively from coolant heated by the engine. Method 400 terminates the flow of electrical current to the PTC heaters when the PTC heaters are activated. Since the engine is at operating temperature, it can provide sufficient heat to warm the passenger compartment without activating the PTC heaters, thus saving electrical energy. Method 400 also allows the position of valve 251 to be adjusted so that coolant flows through radiator 231 when the engine temperature reaches a desired temperature. Furthermore, valve 250 is adjusted to allow coolant flow from valve 251 to the intermediate heat exchanger 242 and the heater core 244.Procedure 400 progresses to completion after coolant has been provided to heat the passenger compartment solely using the engine.

[0055] In procedure 404, procedure 400 decides whether a driver-requested torque is less than (KA) a threshold level and whether the vehicle decelerates. In one example, a driver-requested torque can be determined by the position of an accelerator pedal. Procedure 400 can also decide that the vehicle is decelerating based on a reduction in vehicle speed. In still other examples, procedure 400 can use a global positioning system (GPS) or other means to decide whether the vehicle is traveling downhill and whether a driver-requested torque is less than a threshold torque. If procedure 400 decides that a driver-requested torque is less than a threshold torque, and if the vehicle is decelerating or traveling downhill, the answer is "yes," and procedure 400 proceeds to 406.Otherwise, the answer is "No", and procedure 400 proceeds to 420.

[0056] In procedure 406, regenerative braking is activated by procedure 400, and the vehicle's kinetic energy is converted into electrical energy by means of a starter / generator or other electric machine integrated into the powertrain. The electric machine operates in generator or alternator mode while regenerative braking is activated. The electrical energy generated during regenerative braking is transferred to a vehicle energy bus so that it can be supplied to a battery, PTC heaters, and other electrically operated devices. Naturally, the voltage supplied by the electric machine can be increased or decreased to match the voltage limits of components. After regenerative braking is activated, procedure 400 proceeds to procedure 408.

[0057] In method 408, electrical energy generated from the vehicle's kinetic energy is directed to PTC heaters. By supplying the PTC heaters with the vehicle's kinetic energy while the battery is charged to a level greater than the state of charge (SOC), it may be possible to heat the engine and passenger compartment without reducing the vehicle's range in an electric drive mode, where only the electric motor provides torque to the vehicle's wheels to propel it. The electrical energy supplied to the PTC heaters can be varied in response to the coolant temperature to provide a desired engine coolant temperature. The desired engine coolant temperature can be varied depending on whether heat is required for the passenger compartment and the current engine temperature.Procedure 400 proceeds to 410 once electrical energy generated during regenerative braking is directed to the PTC heating devices.

[0058] In procedure 400, the engine is heated using PTC heaters in device 410. The engine is heated by activating the PTC heaters and adjusting the position of valve 250 so that no coolant flows through bypass line 252, while coolant flows through the internal combustion engine 12. Additionally, valve 251 can be adjusted so that coolant exiting the internal combustion engine 12 bypasses the radiator 231. Bypassing the radiator 231 allows additional thermal energy to be stored in the coolant before it is reheated by the PTC heaters. Heating the engine in this way reduces its preheating time.Furthermore, preheating the engine can improve fuel vaporization when the engine is restarted, thus reducing fuel consumption for restarting and potentially lowering engine emissions. Therefore, the engine and passenger compartment can be warmed using PTC heaters without drawing electrical energy from a battery or other engine storage device during regenerative braking. Such operation of the PTC heaters can help maintain or extend a vehicle's driving range. Method 400 proceeds to completion after activating PTC heaters to warm the engine.

[0059] In this way, the process is made up of Fig. 4. A method for heating a vehicle is provided, comprising: increasing the temperature of a coolant in a coolant circuit having a heater heat exchanger by supplying electric current to a positive temperature coefficient (PTC) heater in response to an ambient temperature lower than a threshold temperature, and increasing the temperature of the coolant by means of heat transferred by a heat pump in response to an ambient temperature higher than the threshold temperature. The method includes the PTC being arranged on the heat exchanger.

[0060] In some examples, the method also includes not operating the heat pump when the PTC heating elements are in operation. The method specifies that heat transferred by the heat pump is transferred using a heat exchanger. The method also includes heating the refrigerant using a motor. The method also includes deactivating the PTC heating element in response to a motor temperature exceeding a threshold temperature. The method specifies that the heat pump is a compression heat pump.

[0061] Through the process from Fig. 4. A method for heating a vehicle is also provided, comprising: heating a passenger compartment using PTC heaters, which, in response to a request to heat the passenger compartment and while not operating in regenerative braking mode, transfer heat to a coolant without heating an engine; and heating the engine using the PTC heaters in response to entering regenerative braking mode. The method also includes terminating the engine heating in response to the termination of regenerative braking mode. The method features an electric machine supplying current to the PTC heaters during regenerative braking mode. The method features the coolant flowing through a heater heat exchanger.

[0062] In some examples, the method specifies that the PTC heaters are arranged at a heat exchanger that transfers heat from a heat pump to the coolant. The method specifies that the PTC heaters are activated in response to an ambient temperature below a threshold temperature. The method specifies that the vehicle has an engine, and that the engine does not burn air and fuel.

[0063] Fig. Figure 5 shows an example simulated sequence for operating a vehicle heating system. The vertical markers T0 to T10 represent times of interest during the operating sequence.

[0064] The first curve from the top in Fig. Figure 5 is a curve of engine temperature versus time. The x-axis represents time, with time starting on the left side of the curve and increasing in the direction of the x-axis arrow. The y-axis represents an engine temperature (e.g., engine coolant temperature, cylinder head temperature, or other engine temperature), and the engine temperature increases in the direction of the y-axis arrow.

[0065] The second curve from the top in Fig. Figure 5 is a curve of a PTC heater state versus time. The x-axis represents time, with time starting on the left side of the curve and increasing in the direction of the x-axis arrow. The y-axis represents a PTC heater state. The PTC heater is off when the PTC heater state is at a lower level. The PTC is on when the PTC heater state is at a higher level.

[0066] The third curve from the top in Fig. Figure 5 is a curve representing a passenger compartment heat demand against time. The x-axis represents time, with time starting on the left side of the curve and increasing in the direction of the x-axis arrow. The y-axis represents a passenger heat demand state. A passenger heat demand is not made when the passenger heat demand state is at a lower level. A passenger heat demand is made when the passenger heat demand state is at a higher level.

[0067] The fourth curve from the top in Fig. Figure 5 is a curve of regenerative braking versus time. The x-axis represents time, with time starting on the left side of the curve and increasing in the direction of the x-axis arrow. The y-axis represents the regenerative braking state. Regenerative braking is off when the regenerative braking state trace is at a lower level. Regenerative braking is on when the regenerative braking state trace is at a higher level.

[0068] The fifth curve from the top in Fig. Figure 5 is a curve of a battery's state of charge (SOC) versus time. The x-axis represents time, starting on the left side of the curve and increasing in the direction of the x-axis arrow. The y-axis represents the battery's SOC, increasing in the direction of the y-axis arrow. The horizontal line 502 represents a low battery SOC threshold.

[0069] The sixth curve from the top in Fig. Figure 5 is a curve of drive torque versus time. The X-axis represents time, and time starts on the left side of the curve and increases in the direction of the X-axis arrow. The Y-axis represents torque requested by the driver, and the torque requested by the driver increases in the direction of the Y-axis arrow.

[0070] The seventh curve from the top in Fig. Figure 5 is a curve of a motor operating state versus time. The X-axis represents time, with time starting on the left side of the curve and increasing in the direction of the X-axis arrow. The Y-axis represents a motor operating state. The motor is off and not running when the motor operating state trace is at a lower level. The motor is running when the motor operating state trace is at a higher level.

[0071] At time T0, the engine is not running, and the engine temperature is at a lower level. The PTC heaters are not activated, and no heat is being requested for the passenger compartment. The battery state of charge (SOC) is at a higher level, and regenerative braking (e.g., braking by applying negative drivetrain torque using an electric machine operating in generator mode) is not activated. The torque requested by the driver is also at a lower level. Such conditions may indicate that a vehicle has been parked and is being activated for driving.

[0072] At time T1, the engine remains off, and the driver requests heat for the passenger compartment. The PTC heaters are activated in response to this request. The PTC heaters are powered by the vehicle battery. The battery charge level is relatively high and begins to decrease when the PTC heaters are activated. The driver requests increased torque, and an electric motor delivers torque to the vehicle wheels in response. The engine is not running. Such conditions may indicate the operation of a hybrid vehicle with a charged battery. The engine temperature is not elevated because coolant heated by the PTC heaters is circulated around the engine and to a heater core.

[0073] At time T2, the driver withdraws the request for passenger compartment heating, and the PTC heaters are switched off in response to the absence of this request. The motor temperature remains at a lower level because the motor is not engaged. The battery state of charge (SOC) continues to decrease, and the driver-requested torque increases in response to the driver requesting additional torque to propel the vehicle. The vehicle has not entered regenerative braking mode.

[0074] At time T3, no heating request is made for the passenger compartment, and the vehicle enters regenerative braking mode in response to low driver-requested torque and deceleration (not shown). The PTC heaters are activated in response to the vehicle entering regenerative braking mode and the battery state of charge (SOC) increasing. The motor temperature begins to rise as heat is transferred from the PTC heaters to the motor. The motor remains stopped, and the battery SOC continues to increase as electrical current is supplied to the PTC heater and the vehicle battery.

[0075] At time T4, the torque requested by the driver increases, and the vehicle exits regenerative braking mode in response to this increase. The PTC heaters are deactivated to conserve electrical current for propulsion. The request for passenger compartment heating is no longer made, and the battery charge level begins to decrease. The motor remains off, and its temperature stabilizes at a moderate level.

[0076] At time T5, the driver requests heat for the passenger compartment. The PTC heaters are activated in response to this request, and heat is supplied to the passenger compartment via a heated coolant. The battery state of charge (SOC) continues to decrease, and the torque requested by the driver stabilizes at a mid-range level. The motor remains off.

[0077] At time T6, the battery state of charge (SOC) has decreased to a level below the lower threshold of 502. The motor is started and activated in response to the lower battery SOC. The torque requested by the driver remains constant, and the PTC heaters continue to warm the coolant and passenger compartment while the engine preheats. The vehicle is not in regenerative braking mode, and the passenger compartment heating request continues. The PTC heaters are deactivated in response to the engine starting and the engine coolant temperature increasing.

[0078] At time T7, the demand for heat to the passenger compartment is withdrawn. The PTC heaters remain off, and the engine temperature continues to rise. The battery state of charge (SOC) has stabilized at a lower level, and the torque requested by the driver increases in response to accelerator pedal input. The vehicle is not in regenerative braking mode, and the engine is burning air-fuel mixtures.

[0079] At time T8, the vehicle enters regenerative braking mode in response to low torque requested by the driver and deceleration. The PTC heaters are not activated because the motor is running and its temperature is at a higher level. The battery state of charge (SOC) increases as electrical current from regenerative braking is fed back into the battery. The request for heat to the passenger compartment remains unfulfilled.

[0080] At time T9, the vehicle exits regenerative braking mode in response to an increase in torque requested by the driver. The engine is deactivated shortly thereafter, and the electric motor provides power to propel the vehicle. A request for passenger compartment heating is also made at time T9 in response to a driver request. The PTC heaters are not activated because the engine temperature is high and heat can be transferred from the engine coolant to the passenger compartment. The battery state of charge (SOC) is at a higher level.

[0081] At time T10, the engine temperature has decreased, and the PTC heaters are activated in response to the lower engine temperature and the demand for heat in the passenger compartment. The vehicle is not in regenerative braking mode, and the battery state of charge (SOC) continues to decrease. Torque requested by the driver varies according to the driver's torque demand. The engine is not burning any air-fuel mixture.

[0082] As experts will understand, in Fig.The procedures described in section 4 represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Therefore, various illustrated steps or functions may be executed in the illustrated order, in parallel, or, in some cases, omitted. Similarly, the order of processing is not necessarily required to achieve the goals, features, and benefits described here, but serves to simplify illustration and description. Although not explicitly illustrated, those skilled in the art will recognize that, depending on the particular strategy employed, one or more of the illustrated steps or functions may be executed repeatedly.

[0083] This concludes the description. Reading this description may bring to the attention of those skilled in the art numerous changes and modifications that do not deviate from the inventive concept and the scope of protection described. For example, the present description could be advantageously applied to R3 (I3-), R4 (I4-), R5 (I5-), V6, V8, V10 and V12 engines operating on natural gas, gasoline, diesel or alternative fuel configurations.

[0084] It is further described as follows: A. Method for heating a vehicle, the method comprising: increasing the temperature of a coolant in a coolant circuit having a heater heat exchanger by supplying electric current to a positive temperature coefficient (PTC) heater in response to an ambient temperature lower than a threshold temperature, and Increasing the temperature of the coolant using heat transferred by a heat pump in response to an ambient temperature higher than the threshold temperature. B. Method according to A, wherein the PTC is arranged at the heat exchanger and the method also includes transferring heat to the coolant using the heat pump and the PTC heating devices. C. Method according to A, which also includes not operating the heat pump when the PTC heating devices are in operation. D. Method according to A, wherein heat transferred by the heat pump is transferred using a heat exchanger. E. Method according to A, which also includes heating the coolant using a motor. F. Method according to E, which also includes deactivating the PTC heating device in response to a motor temperature that is higher than a threshold temperature. G. Method according to A, wherein the heat pump is a compression heat pump. H. Method for heating a vehicle, the method comprising: heating a passenger compartment using PTC heating devices which, in response to a request to heat the passenger compartment and while no operation is taking place in a regenerative braking mode, transfer heat to a coolant without heating an engine, and Heating the motor using the PTC heating devices in response to entering regenerative braking mode. I. Method according to H, which also includes terminating the heating of the engine in response to exiting the regenerative braking mode. J. Method according to H, wherein an electric machine supplies current to the PTC heating devices during the regenerative braking mode. K. Method according to H, wherein the coolant flows through a heating heat exchanger. L. Method according to H, wherein the PTC heating devices are arranged at a heat exchanger which transfers heat from a heat pump to the coolant. M. Method according to H, wherein the PTC heating devices are activated in response to an ambient temperature that is lower than a threshold temperature. N. Method according to H, wherein the vehicle has an engine, and wherein the engine does not burn air and fuel. O. Vehicle system, which includes: a coolant circuit with a positive temperature coefficient (PTC) heating device immersed in a coolant, the coolant flowing through a heater heat exchanger and a heat exchanger, and a heat pump that includes a heat exchanger. P. Vehicle system according to O, wherein the heating heat exchanger is located in a passenger compartment. Q. Vehicle system according to O, which also includes a control unit, wherein the control unit has instructions stored in a non-volatile memory for heating an engine using the PTC heating device. R. Vehicle system according to Q, which also includes further executable instructions stored in the non-volatile memory for supplying heat to a passenger compartment. S. Vehicle system according to Q, which also includes further executable instructions stored in the non-volatile memory for heating the passenger compartment using the PTC heating device. T. Vehicle system according to S, which also includes an electric machine that supplies power to the PTC heating device during regenerative braking.

Claims

[1] Method for heating a passenger compartment of a vehicle (10) wherein the method comprises: Increasing the temperature of a coolant in a coolant circuit (230) comprising a heating heat exchanger (244) by supplying an electric current to a heating device with a positive temperature coefficient (265) in response to an ambient temperature lower than a threshold temperature, and Increasing the temperature of the coolant using heat transferred by a heat pump (232) in response to an ambient temperature higher than the threshold temperature, wherein the heating device with a positive temperature coefficient (265) is arranged in an intermediate heat exchanger (242), and wherein the heat pump (232) contains a compressor (260). [2] Method according to claim 1, which further comprises not operating the heat pump (232) when the heating device with a positive temperature coefficient (265) is in operation. [3] Method according to claim 1, further comprising heating the coolant using a motor (12). [4] Method according to claim 3, further comprising deactivating the heating device with a positive temperature coefficient (265) in response to a temperature of the motor (12) that is higher than a threshold temperature. [5] Method according to claim 1, wherein the heat pump (232) is a compression heat pump.

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