System and method for controlling a vehicle with an electric heater

Abstract

A method for controlling a hybrid vehicle with an internal combustion engine and an electric heater, comprising: instruct the electric heater to switch on; and Starting the engine when an actual power consumption of the electric heater is below a corresponding threshold based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Application Serial No. 61 / 716,474, filed October 19, 2012, entitled "System and Method for Controlling a Vehicle Having an Electric Heater," the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to a heating control strategy for a vehicle with an electric heater. GENERAL STATE OF THE ART

[0003] Electric heating systems can be used to supplement the heat provided by an internal combustion engine and to heat the passenger compartment of a vehicle. While such heating systems are often found in electric vehicles powered solely by a traction battery and in hybrid vehicles with an internal combustion engine combined with a traction battery, they can also be found in other applications. For example, electric heating systems can be used in air conditioners, dehumidifiers, dryers, portable heaters, and other electrical devices.

[0004] To provide passenger comfort in automotive applications, vehicles have the ability to heat or cool the passenger compartment. Conventional vehicles use waste heat from the internal combustion engine as the sole source of heating for the passenger compartment. With the introduction of battery electric vehicles (BEVs), little or no waste heat is available for use in heating the vehicle cabin. As such, BEVs can use an electric heater to warm the passenger compartment. Although hybrid electric vehicles (HEVs) contain a small internal combustion engine that can provide some waste heat for heating the vehicle cabin, these vehicles are similarly designed to minimize the use of the internal combustion engine to maximize fuel economy.As such, these vehicles present different heating challenges because the internal combustion engine may not always be running, generating waste heat for use by the heating system. Plug-in hybrid electric vehicles (PHEVs) exacerbate this problem because they run with the internal combustion engine off for significant periods. To provide optimal fuel economy benefits, it is desirable to heat the passenger compartment without relying solely on internal combustion engine waste heat.

[0005] As such, various alternatives for heating the passenger compartment of electric and hybrid vehicles have been developed. One such solution uses an electric heater as a heat source to provide heat for electric vehicles or to supplement heat from the internal combustion engine in hybrid vehicles when the internal combustion engine waste heat is insufficient to meet a heating demand for the vehicle cabin. An electric heater generally includes one or more heating elements that act as electrical resistors, converting electricity into heat. Electric heaters may include a thermostat to regulate heat output. Alternatively, electric heaters may include heating elements with a positive temperature coefficient (PTC).PTK heating elements consist of small ceramic bricks that exhibit an electrical resistance that increases with temperature, providing self-limiting temperature characteristics, eliminating the need for a thermostat. PTK heaters also feature fast heating response times and the ability to automatically vary the resistance and associated current / power to maintain a predefined temperature.

[0006] DE 10 2004 024 212 A1 describes a method for controlling the operation of a motor vehicle with an internal combustion engine (12), in particular a hybrid vehicle with at least one additional electric motor (14), and an automatic start-stop system (30). The system comprises an automatic shutdown system which, when stop conditions are present, causes the internal combustion engine (12) to be automatically shut off or suppresses the restart of a switched-off internal combustion engine (12), and an automatic startup system which, when start conditions are present, causes the internal combustion engine (12) to start automatically. It is provided that a first stop condition exists when (a) a vehicle speed is greater than 0 km / h and at least one of the following conditions is met: (b) a disengaged clutch (20) and (c) a vehicle transmission (16) is in the neutral position.

[0007] KR 2011 0 044 549 A describes a power monitoring device and method for vehicles to improve vehicle reliability by determining abnormal operation for vehicle energy consumption through a comparison with the vehicle battery and the power consumed in each part. The vehicle power monitoring method includes: a battery power monitoring step for monitoring the generated battery power and transmitting the battery power when a battery is discharged in the BMS; a consumption power monitoring step; a power difference and reference difference comparison step; a power difference maintenance confirmation step; and a fault diagnosis step.

[0008] DE 203 20 474 U1 describes an electric heater for a vehicle with several groups of heating elements connected in parallel, each group comprising at least one heating element; with several switch elements for selectively switching the heating element groups on and off; with a control unit for controlling the switch elements to switch them on and off;with a total current determination unit for determining the sum of the currents through all of the heating element groups that are switched on, and with a monitoring unit for monitoring the heating element group for short circuits or line breaks, wherein the monitoring unit determines the difference between the total current flowing before a heating element group is switched over and the total current flowing after the switching over, and wherein the monitoring unit detects a short circuit in the switched heating element group if the current difference is greater than a predefinable short circuit threshold value, and detects a line break if the current difference is less than a break threshold value;

[0009] Various commercially available electrical component heaters may include certain built-in diagnostic or self-test functions to determine the heater's operating status. However, these diagnostics may be insufficient or unsuitable for some applications. In particular, built-in heater diagnostics may not provide sufficient or timely feedback to determine whether the heater is operating as desired for a particular application. In automotive applications, these diagnostics may require multiple key cycles to detect or report various operating conditions, may not be able to detect some operating anomalies, and / or may not possess the desired accuracy or granularity in detecting various conditions.

[0010] None of the above-mentioned prior art documents discloses the subject matter of present claim 1 nor of the dependent claims thereon. BRIEF DESCRIPTION OF THE INVENTION

[0011] A system and method for operating an electric heater are disclosed to determine heater functionality based on actual heater power consumption relative to expected heater power consumption during operating conditions when electrical power consumption can be accurately estimated by other system components. The system and method may also include controlling one or more components to control a second heating source based on the heater functionality.

[0012] In one embodiment, a hybrid vehicle includes: an internal combustion engine, an electric heater, a heat exchanger or heater core, a valve positioned to direct coolant through the internal combustion engine and / or the electric heater to the heater core, and a controller configured to store a diagnostic code when the electric heater is commanded to turn on and when the actual electric heater power consumption is below a corresponding threshold associated with an expected electric heater power consumption. In various embodiments, the measured and / or estimated electric heater power consumption is determined during vehicle operating conditions when other electrical power-consuming components are off or operating in a known power consumption state.Embodiments may also include starting the engine to provide heat to vehicle components and / or the vehicle cabin. In one embodiment, a sensor configured to measure coolant temperature exiting the electric heater provides a corresponding signal to the controller, and the controller estimates expected electric heater power consumption based on the coolant temperature and the commanded electric heater duty cycle.

[0013] Embodiments according to the present disclosure may include a method for controlling a hybrid vehicle having an internal combustion engine and an electric heater, including receiving a heat request and estimating an actual power consumption of the electric heater. The actual power consumption may be based on the actual power consumption of the electric heater integrated over a predetermined time interval, wherein the actual power consumption is further based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. The method also includes comparing the actual power consumption of the electric heater to a corresponding threshold and storing a diagnostic code if the actual power consumption is below the corresponding threshold.The corresponding threshold may be based on an expected electric heater power consumption estimated from a coolant temperature and a current duty cycle, wherein the coolant temperature may be obtained from a corresponding sensor that measures the coolant temperature exiting the electric heater. Furthermore, the measured electric heater power consumption is based on the power supplied by the traction battery, and the at least one vehicle component may include at least one of a DC / DC converter, an inverter system controller, and an electric compressor.

[0014] In various embodiments, a method for controlling a vehicle having an internal combustion engine and an electric heater may include commanding the electric heater to turn on, and starting the engine, when an actual power consumption of the electric heater is below a corresponding threshold based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. The actual power consumption of the electric heater may be averaged over a predetermined time interval, integrated over a time period, or may be based on an instantaneous measurement of power consumption. The method may further include controlling a valve to selectively direct coolant from the internal combustion engine to a heater core to heat the vehicle when the actual power consumption of the electric heater is below the corresponding threshold.

[0015] Embodiments according to the present disclosure provide various advantages. For example, according to various embodiments, a controller of an electric heater and / or a vehicle with an electric heater performs opportunistic diagnostic testing under operating conditions when operating conditions of other electrical loads are known to provide more accurate and timely feedback of the electric heater's functionality based on an estimated heater power consumption relative to the expected heater power consumption. Embodiments of the present disclosure provide additional diagnostic granularity (diagnostic structure) to more accurately identify various operating conditions associated with the heater functionality and related electrical system components to facilitate repair operations.

[0016] The above advantages and other advantages and features will be readily apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a representative embodiment illustrating the operation of a heating control strategy for a hybrid vehicle according to the present disclosure; Fig. 2 is a schematic diagram of an internal combustion engine coolant circuit for a vehicle according to an embodiment of the present disclosure, and Fig. 3 is a flowchart illustrating operation of a system and / or method for operating an electric heater according to embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to variously employ the present invention.

[0018] Various embodiments of a heating control strategy according to the present disclosure may be implemented in vehicles, which may include, for example, vehicles with a powertrain having a single propulsion device, such as an internal combustion engine or an electric machine (electric motor / generator or traction motor) powered by a traction battery. Vehicles may also have two or more propulsion devices. For example, the vehicle may have an internal combustion engine and an electric motor, a fuel cell and an electric motor, or other combinations of propulsion devices as known in the art. The internal combustion engine may be a compression-ignition or spark-ignition internal combustion engine, or an external combustion engine, and the use of different fuels is contemplated.In one example, the vehicle is a hybrid electric vehicle (HEV) with an internal combustion engine and a battery-powered traction motor, and may additionally have the capability of connecting to an external power grid, such as a plug-in hybrid electric vehicle (PHEV). The PHEV structure is used in the figures and to describe the following various embodiments, but it is contemplated that various embodiments may be used with vehicles having other propulsion devices or combinations of propulsion devices, as is known in the art.

[0019] A plug-in hybrid vehicle (PHEV) is an extension of existing hybrid vehicle (HEV) technology, in which an internal combustion engine is supplemented by a traction battery and at least one electric motor to further achieve greater mileage and reduced vehicle emissions. A PHEV uses a larger-capacity battery than a standard hybrid vehicle and is complemented by the ability to recharge the battery from an electrical grid that delivers energy to a power outlet at a charging station. This further improves overall vehicle system operating efficiency in an electric driving mode and in a hydrocarbon / electric mixed driving mode.

[0020] Fig. 1 illustrates the powertrain configuration and control system of an HEV 110. A power-split HEV 110 may be a parallel HEV. The HEV configuration as shown is for example purposes only and is not intended to be limiting, as the present disclosure applies to BEVs, HEVs, and PHEVs with any suitable architecture. In this powertrain configuration, there are two power sources connected to the driveline, which includes a combination of engine and generator subsystems, using a planetary gear set 122 to interconnect them, and the electric drive system (electric motor, generator, and battery subsystems). The battery subsystem is an energy storage system for the generator and electric motor. The variable generator speed varies the engine output split between an electrical path and a mechanical path.In a vehicle 110 having a power split driveline system, unlike conventional vehicles, the internal combustion engine 116 requires either the generator torque resulting from engine speed control or the generator braking torque to transmit its output power to the driveline for forward motion through both the electrical and mechanical paths (split modes) or the fully mechanical path (parallel mode), as is generally known in the art.

[0021] During operation using the second power source, the electric motor 120 draws power from the battery 126 and provides propulsion independent of the internal combustion engine 116 for forward and reverse motion. This operating mode is referred to as "electric propulsion" or electric-only mode or EV mode. The operation of this power-split powertrain system, unlike conventional powertrain systems, integrates the two power sources to work seamlessly together to meet driver demand without exceeding system limits (such as battery limits), while optimizing the overall efficiency and performance of the powertrain system.

[0022] As in Fig. 1, a vehicle system controller (VCS) 128 coordinates the control of the powertrain in addition to implementing the vehicle heating strategy as described with reference to Fig. 2. Under normal powertrain conditions, the VSC 128 interprets the driver requests (e.g., PRND and acceleration or deceleration demand) and then determines the wheel torque command based on the driver request and powertrain limits. The VSC 128 also determines when and how much torque each power source must deliver to meet the driver torque demand and achieve the operating point (torque and speed) of the internal combustion engine. The battery 126 may also be rechargeable in a configuration of the PHEV vehicle 110 (shown in outline) using an outlet 132 connected to the electrical grid or other external electrical power source and coupled to the battery 126, possibly through a battery charger / converter 130.

[0023] The vehicle 110 may operate in electric vehicle (EV) mode, in which the battery 126 supplies all power to the electric motor 120 to operate the vehicle 110. In addition to the fuel savings benefit, operating in EV mode may improve driver comfort through reduced noise and better drivability, e.g., quieter electric operation, lower noise, vibration, and harshness (NVH), and faster response. Operating in EV mode also benefits the environment through zero emissions from the vehicle during this mode. However, operating in EV mode provides little or no waste heat that can be used to heat the passenger cabin or to heat various other vehicle components to provide desired vehicle performance or emissions control when the internal combustion engine 116 is started and running, for example.The vehicle 110 may include a climate control system with various climate control functions coordinated by the controller 128. Alternatively, a separate climate control computer may be provided and may communicate with the VSC 128 over a wired or wireless network using a standard protocol such as, for example, the Controller Area Network (CAN) protocol. The VSC may include various inputs (e.g., engine coolant temperature sensor (ECTS) and heater core temperature sensors (HCTS1, HCTS2)) and outputs connected to sensors and actuators for controlling heating and cooling of the vehicle cabin and / or vehicle components in response to operator input and / or vehicle and ambient operating conditions.For example, the VSC 128 may include outputs connected to the electric water pump (EWP) 140, the auxiliary water pump (AWP) 142, the heater core isolation valve (HCIV) 144, and the engine coolant valve (ECV) 146. A human machine interface (HMI) implemented using voice activation, a touchscreen, and / or knobs, sliders, and buttons may be used to set a desired cabin temperature or operating mode used by the VSC 128 and / or a climate control system computer to implement the vehicle heating strategy, as described in more detail herein.

[0024] Various approaches are taken to meet vehicle heating demand, which may be based on operator input and / or ambient operating conditions as previously described. With reference to Fig. 2 shows an embodiment of a vehicle heating strategy for heating the passenger compartment of a hybrid vehicle. Fig. The system or method for vehicle heating illustrated in Figure 2 provides two sources of coolant heating. The system may use heat from the internal combustion engine 116 to heat the coolant, as in a conventional vehicle employing an internal combustion engine. The system may also use an electric heater 224, implemented in this embodiment by a PTC heater, to heat the coolant. Multiple heat sources allow flexibility during normal operating conditions and some redundancy during operating conditions when heat from one source is insufficient or unavailable. Coolant from the various heat sources flows through the heater core 230. The system may use an HCIV 144 that selectively directs coolant from the various heat sources. A VSC module 128 (in Fig. 1) may control the operation of the system or may coordinate control of the system with a climate control computer or control module, as previously described. The VSC module 128 may determine the heating mode based on the heat demand and the status of the various components in the heating system, and in particular, the status of the electric heater 224.

[0025] Further with reference to Fig. 2, the system may also utilize an AWP 142 and an EWP 140 to push coolant through the system. Multiple temperature sensors may be used to measure the temperature of coolant entering and exiting the heater core 230. For example, a first heater core temperature sensor (HCTS1) 226 may be included to measure the temperature of coolant exiting the electric heater 224, and a second heater core temperature sensor (HCTS2) 228 may be included to measure the temperature of coolant exiting the heater core 230. The system may also include a radiator 222 for dissipating heat in the coolant and a thermostat 218 for controlling the flow of coolant between the radiator 222 and the engine 116.

[0026] As in Fig. 2, multiple coolant paths are available for heating coolant. The illustrated coolant paths include an all-electric heater loop 210, a combined heater loop 212, an engine cooler loop 216, and an engine bypass loop 214. The all-electric heater loop 210 directs coolant through the electric heater 224, the AWP 142, HCT sensors 226, 228, and the heater core 230. In this heater loop, the electric heater 224 alone heats the coolant, independent of any coolant flowing through the engine. Specifically, the AWP 142 circulates the coolant through the heater core 230 and the electric heater 224.

[0027] In the combined heating loop 212, both the engine 116 and the electric heater 224 can supply heat to the coolant. The EWP 140 can be configured to force coolant through the engine 116 and an electric heater 224. When the engine 116 is running, heat is transferred from the engine 116 to the coolant. The engine coolant can flow through the HCIV 144, the electric heater 224, the AWP 142, and the heater core 230. Additionally, the AWP 142 can also be turned on to assist the flow of coolant through the system.

[0028] Additionally, the HCIV 144 may be configured to allow coolant to flow through either the all-electric heater loop 210 or the combined heater loop 212. The HCIV 144 may be a three-way valve that alternately allows one port to connect to each of the other two ports based on a commanded vehicle operating mode. The HCIV 144 may also be operated to allow coolant to flow from the engine 116 to the electric heater 224, forming the combined heater loop 212. Similarly, the ECV 146 may be configured to allow coolant to flow through the engine bypass loop 214 and / or the engine cooler loop 216.

[0029] The engine cooling loop 216 cools the engine. The engine cooling loop 216 may consist of an EWP 140 that can force coolant through the engine 116 and the radiator 222. The engine cooling loop may also include a thermostat 218 that can regulate the flow of coolant into the engine 116 based on the coolant temperature. In particular, the thermostat 218 allows coolant to flow through the engine cooling loop 216 when the coolant reaches a desired threshold. The cooled fluid then flows back into the engine 116, and the process repeats.

[0030] If the electric heater 224 is inoperative or otherwise unable to provide the desired heat, the controller may store an appropriate diagnostic code and, in response, control the HCIV 144 to direct coolant through the combined heater loop 212. Residual heat from the engine 116 may be used to heat the coolant to a desired target temperature. Alternatively, or in combination, the engine 116 may be started in response to heat the coolant to a target temperature. The system may determine that the electric heater 224 is not functioning as expected by Fig. 1 is measured and / or estimated under operating conditions when the electric heater 224 is the only electrical component in use, such as, for example, at zero vehicle speed with the internal combustion engine 116 off. After minimizing other loads drawing battery power, the battery pack power usage should closely match the power usage of the electric heater if the electric heater is functioning properly. The electrical power demand of the electric heater 224 may be measured or estimated. The method may also work when other components are using electrical power, as long as a measured or estimated power demand is available for those other components.

[0031] Fig. 3 is a flowchart illustrating the operation of a representative embodiment of a system or method for controlling an electric heater and / or vehicle with an electric heater according to the present disclosure. As one of ordinary skill in the art will understand, the Fig. 3 are performed by software and / or hardware depending on the respective application and implementation. The various functions may be performed in a different order or sequence than in Fig. 3. Similarly, one or more steps or functions may be performed repeatedly or in parallel and / or omitted under certain operating conditions or in certain applications, although not explicitly depicted. In one embodiment, the depicted functions are implemented primarily by software, instructions, or code stored in a computer-readable storage device and executed by one or more micro-based computers or controllers to control the operation of the vehicle.

[0032] As in Fig.3, a functionality test is performed whenever a heater is commanded to turn on. The functionality test may include a first phase 310 and a second phase 326. During the first phase 310, the test evaluates whether the electric heater has completed a ramp-up cycle. The ramp-up cycle refers to the period of time necessary for the heater to reach full power. During the second phase 326, the test evaluates the functionality of the electric heater. Specifically, at block 312, it is determined whether the electric heater has completed a ramp-up cycle. If the heater has not completed a ramp-up cycle, an estimated or measured expected power is then compared to a first calibrated power threshold 314.The expected performance is measured and / or estimated based on the duty cycle or commanded heater power, coolant temperature, and coolant flow rate. If the expected performance is not above the first calibrated power threshold at 314, then a first counter is cleared 316 at block 310 and the test returns to the beginning of the first phase of the test. Conversely, if the expected performance is above the first calibrated power threshold at block 314, the first counter is incremented 318 and the first counter is compared to a first calibrated timer value 320 associated with the time period required for the heater to reach full power. If the first counter is not greater than the first calibrated timer, then the ramp-up cycle is not completed 324 and the test returns to block 310.If the first counter is greater than the first calibrated timer value, then a power-up cycle is completed 322 and the test can proceed to the second phase 326.

[0033] During the second phase of the test 326, it is determined whether the expected power is above a second calibrated power threshold 328. If the expected power is below the second calibrated threshold, the functionality test is restarted and returns to the start of the first phase 310. If the expected power is above the second calibrated power threshold at block 328, the test then evaluates whether entry conditions remain 332. Entry conditions 332 may include the following: vehicle speed is zero, the engine is not running, the temperature sensor configured to measure the temperature of the coolant leaving the electric heater is operating, the AWP is operational, and the HCIV is operational.Alternatively, the need to operate the vehicle at zero speed can be eliminated by using a current sensor on the inverter that can measure the actual consumption of the inverter system controller. The power consumption of the electric heater can then be calculated by subtracting the power consumed by the inverter and other components (such as the DC / DC converter and AC compressor) from the total power output of the vehicle battery.

[0034] If no entry conditions remain, a second counter is then cleared and all previously stored values ​​of the actual and expected power consumption are cleared 338, allowing the test to return to the start of the second phase 326. Conversely, if entry conditions remain, the second counter is then incremented at block 334. At block 336, the actual and expected power consumption values ​​are accumulated over a second calibrated timer value associated with the time interval over which the second phase of the functionality test is to run. The actual heater power consumption may be based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. To determine the actual power consumption, the power consumption may be integrated over the second calibrated timer value (energy consumption).In particular, this may involve taking the battery power (voltage multiplied by current) and reducing it by the actual DC / DC converter consumption, the air conditioning consumption, the inverter system controller and / or the transmission power consumption to obtain the actual power corresponding to the heater power consumption.

[0035] At block 340, it is determined whether the second counter is above the second calibrated timer value. If the second counter is not above, the test then returns to the start of the second phase 326. If the second counter is above the second calibrated timer value at block 340, then the actual energy consumption (actual power consumption integrated over the second calibrated timer) is then compared at block 342 to a threshold value that is the expected energy consumption (expected power consumption integrated over the second calibrated timer) adjusted for a predetermined percentage of allowable deviation. If the actual energy consumption is below this threshold, then a diagnostic code is stored at 344. Conversely, if the actual energy consumption is within the allowable deviation, the heater passes the functionality test.

[0036] Alternatively, the actual and expected power consumption can be averaged over the second calibrated timer value and then compared to an appropriate threshold based on an expected power value corrected for the allowable deviation. The instantaneous actual and expected power consumption can also be estimated or measured and compared to an appropriate threshold to determine the functionality of the electric heater.

[0037] Additionally, the controller may be configured to perform other actions in response to storing one or more diagnostic codes 344. Other actions may include, but are not limited to, storing a diagnostic code and / or starting the engine to provide heat to the vehicle. Other actions may also include controlling the HCIV to direct coolant through the combined heater loop and activating an indicator within the vehicle. The indicator may be a light (e.g., a wrench light), a sound, or a message. The purpose of the indicator is to alert the driver to a vehicle problem. When a heat request is present, the controller is configured to perform the functionality test at least once per drive cycle.

[0038] While embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the words used in the application documents are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Furthermore, the features of various implementing embodiments may be combined to form further embodiments of the invention. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as will be appreciated by those skilled in the art, one or more characteristics may be compromised to obtain desired system attributes depending on the specific application and implementation.These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Embodiments discussed herein that are described as being less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for certain applications.

[0039] It is generally described: A method for controlling a hybrid vehicle having an internal combustion engine and an electric heater, comprising: receiving a heat request; estimating an actual energy consumption of the electric heater, wherein the actual energy consumption is based on an actual power consumption of the electric heater over a predetermined period of time, wherein the actual power consumption is based on a measured vehicle power consumption adjusted for power consumed by at least one vehicle component; comparing the actual energy consumption of the electric heater to a corresponding threshold; and storing a diagnostic code if the actual energy consumption is below the corresponding threshold. B Method according to A, wherein the measured vehicle power consumption is based on the power supplied by a traction battery. C Method according to A or B, wherein the at least one vehicle component includes a DC / DC converter, an air conditioning compressor and / or an inverter system controller. D Method according to a method from A to C, wherein the actual energy consumption is estimated after the electric heater has reached a minimum power after being instructed to switch on. E A method according to any one of methods A to D, wherein the corresponding threshold is based on an expected power consumption of the electric heater, integrated over the predetermined time period, adjusted for a certain percentage of deviation. F Method according to a method from A to E, wherein the expected electric heater power consumption is estimated based on the coolant temperature and the current duty cycle of the electric heater. G A method according to a method of A to F, wherein the actual energy consumption of the electric heater is compared with the corresponding threshold after entry conditions are met, the entry conditions including at least one of the following: a sensor configured to measure the temperature of a coolant leaving the electric heater is operational, a pump configured to push coolant through an electrically operated heating loop is operational, a valve configured to selectively direct coolant through the internal combustion engine and / or the electric heater is operational, the vehicle speed is zero, and the internal combustion engine is off. H A method for controlling a hybrid vehicle having an internal combustion engine and an electric heater, comprising: commanding the electric heater to turn on; and starting the engine when an actual power consumption of the electric heater is below a corresponding threshold based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. I Method according to H, wherein the actual power consumption of the electric heater is averaged over a predetermined time interval. J Method according to H or I, wherein the actual power consumption of the electric heater is based on an instantaneous measurement of the power consumption. K Method according to any one of H to J, wherein the actual power consumption of the electric heater is integrated over a predetermined time interval. L A method according to a method of H to K, further comprising: storing a diagnostic code when the actual power consumption of the electric heater is below the corresponding threshold value, indicating an inoperability of the electric heater. M A method according to any one of H to L, further comprising: controlling a valve to selectively direct coolant from the internal combustion engine to a heater core for heating the vehicle when actual electric heater power consumption is below the corresponding threshold. A hybrid vehicle comprising: an internal combustion engine; an electric heater; a heater core; a valve positioned to direct coolant through at least one of the internal combustion engine and the electric heater to the heater core; and a controller configured to store a diagnostic code when the electric heater is commanded to turn on and an actual power consumption of the electric heater is below a corresponding threshold based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. O hybrid vehicle according to N, wherein the actual power consumption of the electric heater is averaged over a predetermined time interval. P Hybrid vehicle according to P or O, where the actual power consumption of the electric heater is based on an instantaneous measurement of power consumption. Q Hybrid vehicle according to a hybrid vehicle from N to P, wherein the actual power consumption of the electric heater is integrated over a predetermined time interval. R hybrid vehicle according to a hybrid vehicle from N to Q, further comprising a sensor configured to measure a temperature of coolant leaving the electric heater, wherein the temperature is used by the controller in conjunction with the current duty cycle to estimate an expected power consumption of the electric heater, and wherein the corresponding threshold is based on the expected power consumption adjusted for an allowable deviation. S Hybrid vehicle after a hybrid vehicle from N to R, where the measured vehicle power consumption is based on the power supplied by a traction battery. T Hybrid vehicle according to a hybrid vehicle from N to S, wherein the at least one vehicle component includes a DC / DC converter, an air conditioning compressor and / or an inverter system controller.

Claims

[1] A method for controlling a hybrid vehicle with an internal combustion engine and an electric heater, comprising: instruct the electric heater to switch on; and Starting the engine when an actual power consumption of the electric heater is below a corresponding threshold based on a measured vehicle power consumption corrected for power consumed by at least one vehicle component. [2] The method of claim 1, wherein the actual power consumption of the electric heater is averaged over a predetermined time interval. [3] The method of claim 1, wherein the actual power consumption of the electric heater is based on an instantaneous measurement of power consumption. [4] A method according to claim 1, wherein the actual power consumption of the electric heater is integrated over a predetermined time interval. [5] The method of claim 1, further comprising: Storing a diagnostic code when the actual power consumption of the electric heater is below the corresponding threshold, indicating that the electric heater is inoperative. [6] The method of claim 1, further comprising: Controlling a valve to selectively direct coolant from the internal combustion engine to a heater core for warming the vehicle when the actual electrical heater power consumption is below the corresponding threshold.

Images