JP7838519B2 - On-vehicle snow melting device - Google Patents

Description

This matter concerns on-board snow-melting devices installed in vehicles.

Conventionally, a device has been known to assist in driving vehicles in cold climates by applying electricity to a heating element attached to the windshield to melt snow accumulated on the glass. This type of heating element is positioned, for example, outside the area wiped by the wiper blades in the vehicle width direction. The wiper blades act to move the snow accumulated on the glass towards the area where the heating element is installed. This efficiently melts the snow on the glass, making it easier to maintain the driver's visibility (see Patent Document 1).

Japanese Patent Publication No. 2009-196458

On the other hand, when driving on unplowed roads or roads with deep ruts formed by snow accumulation, the underside of the vehicle may come into contact with the snow on the road surface, causing the wheels to lift off the road and the vehicle to get stuck. In this case, even if the accelerator pedal is pressed, the wheels will spin freely, necessitating the use of other vehicles or a large number of people to move the vehicle and get the wheels back on the ground. This problem is particularly pronounced in vehicles with low ground clearance (i.e., vehicles whose undersides are more likely to ride up onto the snow on the road surface).

One of the objectives of this invention is to provide an on-board snow-melting device that addresses the aforementioned problems and can resolve vehicle-related issues such as getting stuck due to contact between the snow on the road surface and the underside of the vehicle, using a simple configuration. Furthermore, beyond this objective, other objectives of this invention include achieving effects and benefits not obtainable with conventional technology, derived from the various configurations described in the "Modes for Carrying Out the Invention" section below.

The disclosed vehicle-mounted snow melting device can be realized in the following embodiments (application examples) and solves at least some of the above-mentioned problems. Each of the embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and is also an embodiment that can be omitted. None of the embodiments from Embodiment 2 onward disclose any embodiments or configurations that are essential to this case.

Embodiment 1. The disclosed on-board snow melting device comprises: a heating wire routed on the underside of the vehicle so as to face the road surface on which the vehicle travels; a detection means for detecting the vehicle getting stuck on a snowy road; and a control means for performing control to energize the heating wire when the vehicle getting stuck on a snowy road is detected.
Embodiment 2. In Embodiment 1 described above, it is preferable that the vehicle is an electric vehicle equipped with a drive motor and a traction battery, and that the control means performs control to supply power from the traction battery to the heating element.

Embodiment 3. In Embodiment 2 described above, it is preferable that the vehicle is a hybrid vehicle equipped with a drive engine, and the control means performs control to start the drive engine.
Embodiment 4. In Embodiment 3 described above, it is preferable that the hybrid vehicle is equipped with a generator that generates electricity using the power of the drive engine, and that the control means implements control to supply the power generated by the generator to the traction battery and the heating element.

Embodiment 5. In Embodiment 3 or 4 described above, it is preferable that the exhaust pipe of the drive engine is routed on the underside of the vehicle, and the heating element is routed in a meandering manner so as to avoid the exhaust pipe and cover a planar area when viewed from the underside of the vehicle.
Embodiment 6. In an embodiment including Embodiment 1 described above, it is preferable that the detection means determines that the distance of the wheels from the vehicle body is greater than or equal to a predetermined distance when detecting the stack.

Embodiment 7. In an embodiment including Embodiment 1 described above, it is preferable that the detection means determines an increase in the rotational speed of the drive wheels when detecting the stack.
Embodiment 8. In an embodiment including Embodiment 1 described above, it is preferable that the detection means determines whether the vehicle has stopped when detecting the stack.
Embodiment 9. In an embodiment including Embodiment 1 described above, it is preferable that the detection means determines that the temperature on the underside of the vehicle is below a predetermined temperature when detecting the stack.

According to the disclosed on-board snow-melting device, when a vehicle is detected to be stuck on a snowy road, a control system is implemented that energizes heating wires routed on the underside of the vehicle so as to face the road surface. This efficiently melts the snow accumulated on the underside of the vehicle. As a result, the distance between the underside of the vehicle and the road surface (the bottom of the rut) beneath the wheels can be reduced, allowing the wheels to make contact with the road surface. Therefore, a simple configuration can be used to resolve the issue of the vehicle getting stuck on snowy roads.

This is a block diagram showing the configuration of a vehicle to which the on-board snow melting device of the present invention is applied. Figure 1 is a schematic diagram illustrating the underside structure of the vehicle shown. The configuration of the control device shown in Figure 1 is a block diagram. This is a flowchart illustrating the control flow by the control device. This is a flowchart illustrating the control flow by the control device.

The disclosed on-board snow melting device is applied to the vehicle 10 shown in the following embodiment. This vehicle 10 is provided with a heating element 7 routed on its underside so as to face at least the road surface on which the vehicle 10 travels. The power supplied to the heating element 7 is provided by a power storage device mounted on the vehicle 10. Specific examples of the power storage device include an auxiliary battery (12V battery), the vehicle 10's traction battery, a general-purpose storage battery, a fuel cell, and the like.

Suitable vehicles 10 for applying the disclosed on-board snow melting device include, for example, electric vehicles equipped with a drive motor and a traction battery. In this case, the traction battery, which stores the power to drive the drive motor, can be used as the power source for the heating element 7. Another suitable vehicle 10 is a hybrid vehicle equipped with a drive engine and a generator that generates electricity using engine power. In this case, it is possible to power the heating element 7 using the electricity generated by the generator.

The vehicle 10 described in the following embodiment is a plug-in hybrid electric vehicle (PHEV) equipped with a drive motor, drive engine, generator, and traction battery. A plug-in hybrid vehicle refers to a hybrid vehicle capable of external charging of the traction battery, or external power supply from the traction battery to various electrical appliances. This plug-in hybrid vehicle is equipped with a charging port (inlet) for inserting a charging cable that receives power from an external charging facility, and an outlet for external power supply.

[1. Structure]
Figure 1 is a block diagram showing the configuration of a vehicle 10 to which an on-board snow melting device is applied as an embodiment. This vehicle 10 is a hybrid vehicle (electric vehicle) equipped with a motor 1 (drive motor) and an engine 2 (drive engine) as drive sources, a generator 3 connected to the drive shaft of the engine 2, and an inverter 4 and a battery 5 (driving battery) connected to the motor 1 and generator 3.

Motor 1 is, for example, a three-phase AC synchronous motor and generator. Motor 1 has the function of driving the vehicle 10 using power from the battery 5 or the power generated by the generator 3, and also the function of regenerating power to charge the battery 5. The drive shaft of motor 1 is connected to the drive wheels of the vehicle 10. A transmission mechanism or differential mechanism (not shown) may be interposed in the power transmission path connecting motor 1 and the drive wheels. The number of motors 1 is not limited; for example, a single motor 1 may drive the front and/or rear wheels, or multiple motors 1 may be used to individually drive the front and rear wheels.

Engine 2 is an internal combustion engine, such as a gasoline or diesel engine. The exhaust pipe 6 of engine 2 is routed along the underside of the vehicle 10 in the longitudinal direction. The generator 3 is, for example, a three-phase AC synchronous motor/generator. The generator 3 combines the function of an electric motor that cranks the engine 2 when it starts, and the function of a generator that generates electricity when driven by the engine 2 after it has started. The electricity generated by the generator 3 is used to drive the motor 1 and charge the battery 5. A transmission mechanism (not shown) may be interposed in the power transmission path connecting engine 2 and generator 3.

Battery 5 is a secondary battery capable of supplying a high-voltage DC current of several hundred volts, such as a lithium-ion secondary battery or a nickel-metal hydride battery. Battery 5 is connected to the motor 1 and generator 3 via an inverter 4. The inverter 4 is a power conversion device for converting DC power from the battery 5 to AC power from the motor 1 and generator 3. The inverter 4 incorporates an inverter circuit including switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

The output (torque) of the motor 1 and generator 3 is controlled by controlling the operating state of the inverter 4 (the timing of the on/off switching of the switch element and the drive frequency). The operating state of the inverter 4 is controlled by the control device 20. The control device 20 is an electronic control unit (computer, ECU, Electronic Control Unit) that has the function of controlling at least the output (torque) of the motor 1 and generator 3. Inside the control device 20, for example, there is a processor (central processing unit), memory (main memory), storage device, interface device, etc. The content of the control performed by the control device 20 (control program) is stored in memory, and the content is executed by appropriately reading it into the processor.

Vehicle 10 has two driving modes (control modes for the transmission path of driving force and the combination of driving force used): an EV mode in which the vehicle is driven using motor 1 with engine 2 stopped, and a hybrid mode in which the vehicle is driven using both motor 1 and engine 2 (or, in some cases, only engine 2). The EV mode is automatically selected for relatively low-speed driving conditions, and the hybrid mode is automatically selected for relatively high-speed driving conditions. Various known conditions can be applied to the specific switching conditions for these driving modes.

The underside of the vehicle 10 is equipped with a heating element 7 to melt snow on the underside of the vehicle 10 in case the vehicle 10 gets stuck on a snowy road. The heating element 7 is routed on the underside of the vehicle 10 so as to face the road surface on which the vehicle 10 travels. As shown in Figure 1, the heating element 7 is routed in parallel with the inverter 4, branching off from the DC circuit connecting the battery 5 and the inverter 4. A switch 8 is also installed along the routing path of the heating element 7 to control the energization state of the heating element 7. The operation state of the switch 8 is controlled by the control device 20.

Figure 2 illustrates the routing layout of the heating element 7. In a view from below the vehicle 10, the heating element 7 is routed to avoid the exhaust pipe 6 of the engine 2 and is routed in a meandering manner to cover a planar area. The exhaust pipe 6 of the engine 2, shown in Figure 2, is positioned, for example, near the center of the vehicle's width direction, extending in the longitudinal direction of the vehicle. The rear end of the exhaust pipe 6 is connected to a muffler 16 located at the rear of the underside of the vehicle 10. Furthermore, the underside of the vehicle 10 is covered by a flat underside plate 17, which has a slit-shaped cutout that exposes the exhaust pipe 6 to the underside of the vehicle 10. The exhaust pipe 6 is routed in a layout corresponding to this slit-shaped cutout.

The heating element 7 is routed along the surface of the lower plate 17, on its underside. Preferably, the lower plate 17 is made of a material with high thermal conductivity. Furthermore, to enhance the protection of the exhaust pipe 6, the lower plate 17 is preferably positioned approximately horizontally below the lower end of the exhaust pipe 6. In this case, the heating element 7 is routed below the exhaust pipe 6 (i.e., closer to the road surface than the exhaust pipe 6), making it easier to efficiently melt snow on the underside of the vehicle 10.

In this embodiment, the control device 20 functions as a control means for performing snow-melting control to resolve a stuck state in the vehicle 10 when it becomes stuck on a snowy road. In performing this snow-melting control, the control device 20 controls the operating states of the engine 2, generator 3, inverter 4, switch 8, etc., based on information obtained from various devices. Furthermore, the control device 20 is connected to a tire position sensor 11, an underside temperature sensor 12, an accelerator opening sensor 13, and a wheel speed sensor 14 via an in-vehicle communication network (not shown). The control device 20 performs snow-melting control based on the information acquired by these various sensors 11-14. These various sensors 11-14, in cooperation with the control device 20, function as detection means for detecting when the vehicle 10 is stuck on a snowy road.

The tire position sensor 11 is a sensor for detecting the degree to which the wheel 15 is lifted off the road surface, and it detects the distance from the vehicle body to the axle of the wheel 15. For example, the tire position sensor 11 detects the distance from the vehicle body to the axle of the wheel 15 based on the amount of extension and contraction of the suspension connecting the wheel 15 and the side member. This distance becomes extremely large, for example, when the underside of the vehicle 10 is in contact with snow on the road surface and the wheel 15 is lifted off the road surface. Therefore, if this distance is greater than or equal to a predetermined distance, it can be determined that the wheel 15 is lifted off the road surface. The tire position sensor 11 is provided on at least the drive wheels.

The underside temperature sensor 12 is a sensor that detects the temperature of the underside of the vehicle 10. When the vehicle 10 is traveling on a snowy road, the temperature detected here will be close to the freezing point. Therefore, based on the temperature detected here, it is possible to determine whether or not the vehicle 10 is traveling on a snowy road. The underside temperature sensor 12 is installed at multiple locations on the underside of the vehicle 10, for example, as shown in Figure 2. The accelerator pedal position sensor 13 is a sensor that detects the amount the accelerator pedal is pressed. The wheel speed sensor 14 is a sensor that detects the angular velocity of the wheels 15. Based on the angular velocity detected here, the vehicle speed (movement speed) and odometer value (odometer reading, cumulative distance traveled) of the vehicle 10 are calculated. The wheel speed sensor 14 is installed, for example, on each of the four wheels.

Figure 3 is a block diagram illustrating the specific configuration of the control device 20. This control device 20 includes a PHEV-ECU 21 (vehicle control device), an engine ECU 22 (engine control device), a motor ECU 23 (motor control device), and a BMU 24 (Battery Management Unit). These ECUs 21-24 are connected to each other via an in-vehicle communication network (not shown).

The PHEV-ECU 21 is an electronic control unit that comprehensively manages all other electronic control units installed in the vehicle 10. It monitors the operating status of various devices included in the powertrain and the driving status of the vehicle 10, and centrally manages the operating status of various devices controlled by the various electronic control units. The driving mode of the vehicle 10 is selected and set by the PHEV-ECU 21 based on the driving status of the vehicle 10 and the driver's input. Furthermore, the operating status of switch 8 in this embodiment is controlled by either the PHEV-ECU 21 or the BMU 24.

The engine ECU 22 is an electronic control unit that specializes in controlling the operating state of engine 2. The motor ECU 23 is an electronic control unit that specializes in controlling the operating state of motor 1, generator 3, and inverter 4. The output of motor 1 and generator 3 is controlled by the motor ECU 23. The BMU 24 is an electronic control unit that controls the operating state of battery 5. Here, the voltage, current, temperature, etc., of battery 5 are measured, and the charge level (SOC, State of Charge), degradation level (SOH, State of Health), maximum output, etc., are calculated.

[2. Control]
The snow melting control performed by the control device 20 will be described in detail. The snow melting control in this embodiment is a control that melts the snow accumulated on the underside of the vehicle 10, and is started at least when the vehicle 10 gets stuck on a snowy road. Various conditions for determining whether or not the vehicle is stuck on a snowy road are exemplified below. In this embodiment, the snow melting control is started when both start conditions 1 and 2 are met, and either start condition 3 or 4 is met.

Starting condition 1. The driving mode of vehicle 10 is EV mode.
Starting condition 2. The temperature of the underside of the vehicle 10 is below a predetermined temperature.
Starting condition 3. The wheels 15 (drive wheels) are lifted off the road surface.
Starting condition 4. The vehicle 10 is unable to move in response to accelerator operation.
Starting condition 5. The current location of vehicle 10 is within a snow-covered area.
Starting condition 6. It is snowing at the current location of vehicle 10.
Starting condition 7. The charge level of battery 5 is at or above a predetermined charge level.

The starting condition 1 can be determined based on the driving mode set in the PHEV-ECU 21. Determining starting condition 1 can promote snow melting on the underside of the vehicle 10 in situations where exhaust heat from the engine 2 cannot be expected. Starting conditions 2 to 4 can be determined based on information detected by the various sensors 11 to 14 described above. The predetermined temperature included in starting condition 2 is set to, for example, a temperature close to freezing point, where the presence of snow on the road surface is estimated. Starting condition 3 can be determined, for example, by calculating the distance from the vehicle body to the axle of the wheel 15 based on the detection value of the tire position sensor 11, and confirming that this distance is greater than or equal to a predetermined distance. Alternatively, it can be determined if the state of this distance being greater than or equal to the predetermined distance continues for a predetermined time or longer.

Starting conditions 5 and 6 can be determined based on, for example, the location information of the vehicle 10 measured by a car navigation system (not shown) or weather information obtained via the internet. Starting condition 7 can be determined based on the charge rate calculated by the BMU 24. In addition to the above, other starting conditions may be checked, such as whether the engine 2 or generator 3 is malfunctioning, the degree of battery degradation, and the amount of fuel that can be supplied to the engine 2.

Furthermore, the snow melting control terminates when the vehicle 10 is freed from being stuck. However, if the snow melting control takes an excessively long time, the control may be stopped, taking into consideration possibilities such as over-discharge of the battery 5 or the presence of ice and snow that is difficult to melt. Examples of termination conditions for snow melting control are given below. In this embodiment, the snow melting control terminates when any of termination conditions 1 to 3 are met.

Termination condition 1. The snow melting control operation time exceeds the specified time.
Termination condition 2. The wheel 15 (drive wheel) is in contact with the road surface.
Termination condition 3. Vehicle 10 becomes capable of moving in response to accelerator operation.
Termination condition 4. The charge level of battery 5 falls below the predetermined second charge level.

Termination condition 1 can be determined based on the duration of snow melting control, which is measured by a timer (not shown). The predetermined time included in termination condition 1 is set within a range of, for example, several minutes to several tens of minutes. Termination conditions 2 and 3 can be determined based on information detected by the various sensors 11, 13, and 14 described above, and termination condition 4 can be determined based on the charge rate calculated by the BMU 24. The predetermined second charge rate for termination condition 4 may be the same value as the predetermined charge rate for start condition 7, or it may be a lower value. In addition to the above, other termination conditions may be checked, such as whether there is a malfunction in the engine 2 or generator 3, the degree of battery degradation, and the amount of fuel that can be supplied to the engine 2.

The snow melting control includes a control that melts snow on the underside of the vehicle 10 by energizing the heating element 7 with at least the power from the battery 5. Preferably, in addition to this, it also includes a control that operates the engine 2 (a control that melts snow on the underside of the vehicle 10 using exhaust heat) and a control that energizes the heating element 7 with the power generated by the generator 3 (a control that melts snow on the underside of the vehicle 10 using the power generated by the generator 3). The operating state of the engine 2 is controlled by the engine ECU 22, and the operating state of the generator 3 is controlled by the motor ECU 23. Furthermore, the operating state of the switch 8 of the heating element 7 is controlled by the PHEV-ECU 21 and BMU 24.

[3. Flowchart]
Figures 4 and 5 are flowcharts illustrating the procedure for snow melting control. The flowchart shown in Figure 4 relates to the determination of the start conditions for snow melting control and is executed repeatedly at predetermined intervals when the main switch (main power supply) of the vehicle 10 is ON. The flowchart shown in Figure 5 relates to the determination of the end conditions for snow melting control and is executed repeatedly at predetermined intervals after snow melting control has started, instead of the flowchart shown in Figure 4.

In step A1 of Figure 4, it is determined whether the vehicle 10 is in EV mode. If the driving mode is EV mode, the process proceeds to step A2; otherwise, the control cycle ends. In step A2, it is determined whether or not the accelerator has been operated based on the detection information from the accelerator pedal position sensor 13. If the accelerator has been operated, the process proceeds to step A3; if there has been no accelerator operation, the process proceeds to step A5.

In step A3, it is determined whether the current (latest) tire rotation speed for the drive wheels is greater than the previous value (the value calculated in a previous calculation cycle). Here, it is determined whether the drive wheels are rotating due to accelerator operation. If the drive wheels are rotating, the process proceeds to step A4; if they are not rotating (for example, if the drive wheels are constrained for some reason), the control for this cycle ends.

In step A4, it is determined whether or not vehicle 10 is stuck. For example, it is determined whether the current odometer value, calculated based on the detection value of the wheel speed sensor 14, is equal to the previous value (i.e., whether the odometer value is constant). Alternatively, it is determined whether or not the vehicle speed is approximately zero. If it is determined that vehicle 10 is stuck, the process proceeds to step A6; if it is determined that vehicle 10 is not stuck, the control for this control cycle ends.

In step A5, which is performed when there is no accelerator operation, it is determined whether or not lift of the drive wheels has been detected. For example, it is determined whether the distance from the vehicle body to the axle of the wheel 15, calculated based on the detection value of the tire position sensor 11, is greater than or equal to a predetermined distance. Alternatively, it is determined whether the state of this distance being greater than or equal to the predetermined distance has continued for a predetermined time or longer. If lift of the drive wheels is detected, the process proceeds to step A6; otherwise, the control for this control cycle ends.

In step A6, it is determined whether the temperature of the underside of the vehicle 10 is below a predetermined temperature. While steps A2 to A5 are for detecting when the vehicle 10 is stuck, step A6 is for determining whether the stuck vehicle is stuck on a snowy road. If the temperature of the underside is below the predetermined temperature, the process proceeds to step A7. On the other hand, if the temperature is above the predetermined temperature, it is determined that the vehicle is stuck on a road other than a snowy road, and the control for this control cycle ends.

In step A7, a control signal for connecting switch 8 is output from the PHEV-ECU 21 or BMU 24, energizing the heating element 7 and initiating snow melting control. At this time, a timer (not shown) begins timing, and the duration of the snow melting control is counted. In the subsequent step A8, a control signal for starting engine 2 is output from the engine ECU 22, and engine 2 is driven. Furthermore, the operating states of generator 3 and inverter 4 are controlled by the motor ECU 23, and the power generated by generator 3 is introduced into the DC circuit connecting inverter 4 and battery 5. This supplies power from generator 3 to battery 5 and heating element 7.

When snow melting control is initiated, the flow shown in Figure 5 begins. In step B1 of Figure 5, it is determined whether the snow melting control execution time is less than a predetermined time. If the execution time is less than the predetermined time, the process proceeds to step B2. If the execution time is equal to or greater than the predetermined time, it is determined that the snow melting control termination condition is met, and the process proceeds to step B6. In step B6, a control signal to disconnect switch 8 is output from the PHEV-ECU 21 or BMU 24, stopping the power supply to the heating element 7. In the following step B7, a control signal to stop engine 2 is output from the engine ECU 22, rendering engine 2 inoperable and stopping power generation by generator 3. This completes the snow melting control.

In step B2, it is determined whether or not the accelerator has been operated based on the detection information from the accelerator position sensor 13. If the accelerator has been operated, the process proceeds to step B3; if the accelerator has not been operated, the process proceeds to step B5.
In step B3, similar to step A3, it is determined whether or not the drive wheels are rotating due to accelerator operation. If the drive wheels are rotating, the process proceeds to step B4; otherwise, it proceeds to step B8 and snow melting control continues.

In step B4, it is determined whether the vehicle 10 has been freed from being stuck. For example, it is determined whether the current odometer value, calculated based on the detection value of the wheel speed sensor 14, is greater than the previous value. Alternatively, it is determined whether the vehicle speed is above a predetermined positive speed. If it is determined that the vehicle 10 has been freed from being stuck, the process proceeds to step B6 to terminate the snow melting control. On the other hand, if it is determined that the vehicle 10 is not freed from being stuck, the process proceeds to step B8, and the snow melting control continues.

In step B5, it is determined whether or not the drive wheels have made contact with the ground. For example, it is determined whether the distance from the vehicle body to the axle of the wheel 15, calculated based on the detection value of the tire position sensor 11, is less than a predetermined distance (normal value). Alternatively, it is determined whether the state of this distance being less than the predetermined distance (normal value) has continued for a predetermined time or longer. If contact with the ground is detected for the drive wheels, the process proceeds to step B6 to terminate the snow melting control. On the other hand, if contact with the ground is not detected for the drive wheels, the process proceeds to step B8, and the snow melting control continues.

[4. Effects]
(1) The vehicle-mounted snow melting device according to the above embodiment comprises a heating element 7, detection means (various sensors 11 to 14 and a control device 20), and control means (control device 20). The heating element 7 is routed on the underside of the vehicle 10 so as to face the road surface on which the vehicle 10 travels. The detection means detects when the vehicle 10 is stuck on a snowy road. The control means performs control to energize the heating element 7 when it is detected that the vehicle 10 is stuck on a snowy road.

In the above embodiment, when vehicle 10 is detected to be stuck on a snowy road, a control is implemented to energize the heating element 7, which is routed on the underside of vehicle 10 so as to face the road surface. This efficiently melts the snow accumulated on the underside of vehicle 10. As a result, the distance between the underside of vehicle 10 and the road surface (bottom of the rut) beneath the wheels 15 can be shortened, allowing the wheels 15 to make contact with the road surface (ground contact). Therefore, vehicle 10 can be resolved from being stuck on snowy roads with a simple configuration, improving the usability of vehicle 10.

(2) The above-described on-board snow melting device can be applied to an electric vehicle (vehicle 10) equipped with a drive motor (motor 1) and a traction battery (battery 5), as shown in Figure 1. The control means can also control the supply of power from the traction battery to the heating element 7. This configuration allows for snow melting to be accelerated by utilizing the power of the traction battery, which is not consumed when the vehicle 10 is stuck. Furthermore, since the traction battery can output a larger current compared to, for example, an auxiliary battery, it can efficiently resolve snow-stuck situations in a short time, further improving the convenience of the vehicle 10.

(3) The above-described on-board snow melting device can be applied to a hybrid vehicle (vehicle 10) equipped with a drive engine (engine 2), as shown in Figure 1. The control means can perform control to energize the heating element 7 and simultaneously control to start the drive engine. With this configuration, snow melting can be efficiently promoted by utilizing the heat from the exhaust pipe 6 of the drive engine. Therefore, snow-stuck situations can be resolved quickly and efficiently, further improving the convenience of the vehicle 10.

(4) The above-described on-board snow melting device can be applied to a hybrid vehicle (vehicle 10) equipped with a generator 3 that generates electricity using the power of the drive engine, as shown in Figure 1. The control means can also control the supply of power generated by the generator 3 to the traction battery and the heating element 7. With this configuration, snow-stuck conditions can be resolved quickly and efficiently by utilizing the power generated by the generator 3. Furthermore, since the power of the traction battery can be conserved, a reduction in the remaining driving range after snow-stuck conditions can be prevented, for example, ensuring the driving performance of vehicle 10. Therefore, the convenience of vehicle 10 can be further improved.

(5) In the above embodiment, the exhaust pipe 6 of the drive engine is routed on the underside of the vehicle 10. Furthermore, as shown in Figure 2, the heating wire 7 is routed in a meandering manner to cover a planar area, avoiding the exhaust pipe 6 when viewed from below the vehicle 10. This configuration allows for efficient heating of the area on the underside of the vehicle 10 other than the exhaust pipe 6 using the heating wire 7. Additionally, by not providing the heating wire 7 directly below the exhaust pipe 6, exhaust heat can be efficiently transferred to the snow surface. Moreover, compared to the case where the heating wire 7 is routed across the entire underside of the vehicle 10, the length of the heating wire 7 (total length) can be shortened, thereby increasing energy-saving effects.

(6) The above detection means can determine if the distance of the wheel 15 from the vehicle body is greater than or equal to a predetermined distance when detecting a stuck vehicle. This determination is made, for example, by comparing the distance from the vehicle body to the axle of the wheel 15, as detected by the tire position sensor 11, with a preset predetermined distance. With this configuration, the state in which the wheel 15 is lifted off the road surface can be accurately grasped, and the accuracy of detecting stuck vehicles on snowy roads can be improved.

(7) The above detection means can determine an increase in the rotational speed of the drive wheels when detecting a stuck state. This determination is made, for example, by comparing the current value and the previous value of the tire rotational speed of the drive wheels, as shown in step A3 of Figure 4. With this configuration, the slip state of the drive wheels due to accelerator operation during a stuck state (i.e., the state in which the vehicle 10 does not move forward even when the accelerator pedal is pressed) can be accurately grasped, and the accuracy of detecting a stuck state on a snowy road can be improved.

(8) The above detection means can determine if the vehicle 10 is stopped when detecting a stuck vehicle. This determination is made, for example, by comparing the current odometer value with the previous odometer value, as shown in step A4 of Figure 4. With this configuration, it is possible to accurately determine if the vehicle 10 is stuck (stopped), and the accuracy of detecting stuck vehicles on snowy roads can be improved.

(9) The above detection means can determine if the temperature of the underside of the vehicle 10 is below a predetermined temperature when detecting a vehicle getting stuck. This configuration allows for accurate detection of the vehicle getting stuck due to snow (i.e., not stuck on a muddy or gravel road), improving the accuracy of detecting vehicles stuck on snowy roads.

[5. Others]
The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

In the above embodiment, snow melting control performed when the vehicle 10 is in EV mode has been described in detail, but it may also be performed in other driving modes. The start and end conditions for snow melting control can be changed as appropriate. In the above embodiment, four sensors 11 to 14 were used as examples to describe how they function as detection means in cooperation with the control device 20, but some of the sensors 11 to 14 may also function as detection means. At a minimum, by performing snow melting control when vehicle 10 is detected to be stuck on a snowy road, the snow accumulated on the underside of vehicle 10 can be efficiently melted, and the vehicle 10 can be resolved from being stuck.

Furthermore, in the snow melting control according to the above embodiment, in addition to energizing the heating element 7, the engine 2 is started to generate electricity in the generator 3, and this generated power is used to efficiently melt the snow. However, starting the engine 2 and generating electricity in the generator 3 may be omitted. Also, the power used to energize the heating element 7 may be from the battery 5 (driving battery), or from an auxiliary battery (12V battery) or fuel cell (not shown). The power source for energizing the heating element 7 can be changed as appropriate.

This technology is applicable to the manufacturing industry of on-board snow-melting devices installed in vehicles, and also to the manufacturing industry of vehicles equipped with such devices.

1. Motor (Drive motor)
2. Engine (Drive engine)
3. Generator 4. Inverter 5. Battery (driving battery)
6. Exhaust pipe 7. Heating element 8. Switch 10. Vehicle (electric vehicle, hybrid vehicle)
11. Tire position sensor (detection means)
12. Bottom surface temperature sensor (detection means)
13. Accelerator opening sensor (detection means)
14. Wheel speed sensor (detection means)
15 Wheels 16 Muffler 17 Bottom plate 20 Control device (control means, detection means)
21 PHEV-ECU
22 Engine ECU
23 Motor ECU
24 BMU

Claims (9)

A heating element is routed on the underside of the vehicle so as to face the road surface on which the vehicle travels,
A detection means for detecting when the vehicle gets stuck on a snowy road,
A control means that implements a control to energize the heating element when the vehicle is detected to be stuck on a snowy road,
A vehicle-mounted snow melting device characterized by being equipped with the following features. The aforementioned vehicle is an electric vehicle equipped with a drive motor and a traction battery,
The on-board snow melting device according to claim 1, characterized in that the control means performs control to supply power from the traction battery to the heating element. The aforementioned vehicle is a hybrid vehicle equipped with a drive engine,
The on-board snow melting device according to claim 2, characterized in that the control means performs control to start the drive engine. The aforementioned hybrid vehicle is equipped with a generator that generates electricity using the power of the drive engine,
The on-board snow melting device according to claim 3, characterized in that the control means performs control to supply the power generated by the generator to the traction battery and the heating element. The exhaust pipe of the aforementioned drive engine is routed on the underside of the vehicle,
The on-board snow melting device according to claim 3 or 4, characterized in that the heating element is routed in a meandering manner so as to avoid the exhaust pipe and cover a planar area when viewed from below the vehicle. The on-board snow melting device according to claim 1, characterized in that the detection means determines that the distance of the wheels from the vehicle body is greater than or equal to a predetermined distance when detecting the stack. The on-board snow melting device according to claim 1, characterized in that the detection means determines an increase in the rotation speed of the drive wheels when detecting the stack. The on-board snow melting device according to claim 1, characterized in that the detection means determines that the vehicle has stopped when it detects the stack. The on-board snow melting device according to claim 1, characterized in that the detection means determines that the temperature on the underside of the vehicle is below a predetermined temperature when detecting the stack.