DESC:
TECHNICAL FIELD
The present disclosure relates generally to the field of delivery boxes mounted on vehicles (e.g., a two-wheeler electric vehicle), and more specifically to a system and method for controlling temperature of a delivery box mounted on a vehicle and a heater casing assembly.
BACKGROUND
Typically, a vehicle, such as a two-wheeler, may be utilized to carry various goods. For example, an electric vehicle (e.g., a two-wheeler electric vehicle) may be utilized to transport goods, such as food items, medical supplies, dairy products, or other perishable items. In such a case, a conventional delivery box may be arranged on the two-wheeler vehicle to transport such goods. In certain scenarios, hot food items, such as Pizza, burgers, hot dogs, and the like that are carried in the delivery box and are required to be maintained at high temperatures while transportation in order to sustain the food items for a desired duration.
Currently, there are some conventional attempts made for maintaining the high temperature of the hot food items. Such attempts include the use of delivery boxes made of insulating materials, which prevents loss of heat from the hot food items. However, such containers absorb some amount of heat from the hot food items, which may result in decrease in temperature of the hot food items. Further, the heat from the hot food items may get leaked through edges of the containers, such as through a gap created due to misalignment of a lid of the delivery box. In addition, an inner surface of the container may get warped due to heat absorbed from the hot food items. Thus, there exists a technical problem of how to maintain the temperature within the delivery box mounted on a vehicle.
Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional temperature control systems.
SUMMARY
The present disclosure provides a system and method for controlling temperature of a delivery box mounted on a vehicle and a heater casing assembly. The present disclosure provides a solution to the problem of how to maintain the temperature within the delivery box that can be mounted on a vehicle. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art and provide an improved system, which preserves one or more food items present in the delivery box.
One or more objectives of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.
In one aspect, the present disclosure provides a system for controlling temperature of a delivery box. The system comprises a voltage regulator integrated circuit (IC) configured to regulate an input voltage to provide a regulated 5V DC voltage. Furthermore, the system includes a thermistor configured to sense an internal temperature of the delivery box and provide a resulting voltage corresponding to the sensed temperature, comprises a reference voltage corresponding to a desired temperature within the delivery box. The system further includes a comparator circuit configured to compare the reference voltage from the thermistor with a pre-defined reference voltage corresponding to a desired temperature range and generate a first signal based on the comparison. Furthermore, the system includes a hysteresis circuit coupled to the comparator circuit and configured to introduce hysteresis for low-to-high and high-to-low transitions of the first signal using positive feedback to control such transitions in order to maintain the pre-defined temperature range. Moreover, the system includes a metal-oxide-semiconductor field-effect transistor (MOSFET) coupled to the hysteresis circuit. Moreover, the MOSFET is configured to control conductivity based on the first signal from the hysteresis circuit. Furthermore, the system includes a heater coupled to the MOSFET and configured to provide heat to the delivery box and at least one fan coupled to the heater and configured to circulate air across the heater within the delivery box. Moreover, the system is configured to turn on or turn off the heater based on the first signal from the hysteresis circuit to maintain the internal temperature of the delivery box within the pre-defined temperature range.
Advantageously, the system is configured to provide a robust and an efficient temperature control mechanism for the delivery box to ensure precise temperature regulation within the desired range. Moreover, such temperature control mechanism is used to store food items and other items that require certain temperature range in order to attain their freshness or to prevent them from getting stale. Furthermore, the hysteresis circuit coupled to the comparator circuit is used to maintain the temperature within the predefined range by controlling the transitions and distribute the heat evenly within the delivery box.
In another aspect, the present disclosure provides a method for controlling temperature within a delivery box, the method comprising receiving an input voltage, regulating the input voltage to provide a regulated voltage, sensing, by a thermistor, an internal temperature of the delivery box and providing a resulting voltage corresponding to the sensed temperature, comprising a reference voltage corresponding to a desired temperature within the delivery box; comparing, by a comparator circuit, the reference voltage from the thermistor with a pre-defined reference voltage corresponding to a desired temperature range; generating, by the comparator circuit, a first signal based on the comparison; introducing hysteresis, by a hysteresis circuit coupled to the comparator circuit, for low-to-high and high-to-low transitions of the first signal using positive feedback to control the transitions and maintain the desired temperature range; controlling conductivity of a metal-oxide-semiconductor field-effect transistor (MOSFET) based on the first signal from the hysteresis circuit; and heating the delivery box by a heater coupled to the MOSFET and circulating air across the heater within the delivery box using at least one fan coupled to the heater. Moreover, the heater is turned on or turned off based on the first signal from the hysteresis circuit to maintain the internal temperature of the delivery box within the desired temperature range.
The disclosed method achieves all the advantages and technical effects of the system for controlling temperature within the delivery box of the present disclosure.
In yet another aspect, the present disclosure provides a heater casing assembly. The heater casing assembly comprises a first casing and a second casing forming an enclosure. The heater casing assembly further comprises a heater mount disposed within the enclosure, the heater mount configured to receive a heater. The heater is configured to heat a delivery box. The heater casing assembly comprises at least one fan disposed within the enclosure and configured to draw air into the enclosure and across the heater. The heater casing assembly comprises an upper cover and a lower cover that enclose the first casing and the second casing. The heater casing assembly comprises a printed circuit board (PCB) disposed within the enclosure and configured to provide electrical connections to the heater and the at least one fan. The heater casing assembly comprises at least one ceramic washer configured to restrict heat flow from the heater mount. The heater casing assembly comprises a casing mount configured to secure the heater casing assembly to another structure.
The integrated design of the heater casing assembly allows for efficient heat generation by the heater, air circulation by the fan, and controlled heat transfer to maintain the desired temperature within the delivery box while minimizing heat loss to the exterior. Further, the heater casing assembly protects the system from exterior wear and tear.
It is to be appreciated that all the aforementioned implementation forms can be combined. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity that performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1 is a block diagram that depicts a system for controlling the temperature of a delivery box, in accordance with an embodiment of the present disclosure;
FIG. 2 is a circuit diagram that depicts various electronic components of a printed circuit board (PCB) of a system, in accordance with another embodiment of the present disclosure;
FIG. 3 is a block diagram that depicts a heater casing assembly of a system for controlling temperature of a delivery box, in accordance with another embodiment of the present disclosure;
FIG. 4 is a graphical representation that depicts temperature range of a heater of a system for controlling temperature of a delivery box, in accordance with various embodiments of the present disclosure; and
FIG. 5 is a flow chart depicting a method for controlling the temperature within a delivery box, in accordance with an embodiment of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
FIG. 1 is a block diagram that depicts a system for controlling the temperature of a delivery box, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a block diagram that depicts a system 100 for controlling the temperature of the delivery box.
The system 100 refers to an electronic system for controlling the temperature within the delivery box or container used for transporting food or other temperature-sensitive items. The system 100 includes a battery 120, a heater 114, at least one fan 116, and a printed circuit board (PCB) 122.
The battery 120 refers to a rechargeable electrochemical cell or a pack of multiple such cells, capable of storing electrical energy chemically and supplying electrical power to the system 100. The battery 120 serves as the primary power source for providing an input voltage 118. The heater 114 refers to a heating element, such as a coil or resistive wire, that generates heat to maintain the desired temperature inside the delivery box.
The at least one fan 116 refers to one or more fans used to circulate the heated air throughout the delivery box, ensuring even distribution of heat and efficient temperature regulation. In other words, the at least one fan 116 is an electrical fan, which circulates air within the delivery box to maintain the predefined temperature range uniformly within the delivery box. The at least one fan 116 is advantageous to avoid non-uniform temperature in the food items (i.e., some part of the food is dry and other part is warm, etc.) and preserve the food items for a definite duration of time.
The printed circuit board (PCB) 122 refers to a board made of insulating material used to connect electronic components to create a functioning electronic device. The PCB 122 further comprises a voltage regulator integrated circuit (IC) 102, a thermistor 104, a comparator circuit 106, a hysteresis circuit 112, and a metal-oxide-semiconductor field-effect transistor (MOSFET) 110.
The voltage regulator integrated circuit (IC) 102 refers to an electronic circuit or device that maintains a constant output voltage regardless of changes in input voltage, load current, or temperature. Examples of the voltage regulator may include, but are not limited to a linear voltage regulator, a low dropout linear regulator, a switching regulator, a synchronous buck converter, a programmable linear regulator, and the like. The voltage regulator IC 102 regulates the input voltage 118 from the battery 120 to provide a stable and consistent voltage output required for the operation of other components in the system 100. The voltage regulator IC 102 is advantageous to maintain the stability and reliability of system 100 by ensuring a constant supply of the input voltage 118 to system 100.
The thermistor 104 refers to a temperature-sensing device that changes its electrical resistance in response to changes in temperature. The thermistor 104 is used to sense the internal temperature of the delivery box.
The comparator circuit 106 refers to an electronic circuit that compares a reference voltage 108 from the sensed temperature of the thermistor 104, with the pre-defined reference voltage 108 corresponding to the desired temperature range for the delivery box.
The hysteresis circuit 112 refers to a circuit coupled to the comparator circuit 106 that introduces hysteresis, a phenomenon where the system's 100 output lags behind and depends on the previous state of the input voltage 118. The hysteresis helps prevent rapid oscillations and provides stable temperature control within the delivery box.
The MOSFET 110 refers to a type of transistor used as a switch to control flow of electric current. The MOSFET 110 is configured to control the conductivity and power supplied to the heater 114 based on the signals from the hysteresis circuit 112.
In operation, system 100 receives an input voltage 118 from the battery 120. The battery 120 includes a lithium-ion battery and a Battery Management System (BMS). The use of the battery 120, particularly the lithium-ion battery, as the power source for the system 100 allows the system 100 to operate independently without the need for a constant external power supply, making it suitable for applications such as temperature control in delivery boxes during transportation. Lithium-ion batteries are known for their high energy density, which translates to longer operating times before requiring recharging.
In an embodiment, the BMS is coupled to the voltage regulator integrated circuit 102 and the comparator circuit 106. The BMS is configured to provide the input voltage 118 from the battery 120. The BMS protects the system 100 from short circuits and provides overcurrent protection. Coupling the BMS to the voltage regulator IC 102 the comparator circuit 106 ensures that the regulated voltage supplied to the other components of the system 100 is protected from potential voltage fluctuations or abnormal conditions. The BMS acts as a gatekeeper, providing the input voltage 118 to the voltage regulator IC 102 the comparator circuit 106 while also safeguarding the system 100 from short circuits and overcurrent situations.
The voltage regulator integrated circuit (IC) 102 of the system 100 receives an input voltage 118 from the battery 120 and regulates the input voltage 118 to provide a stable output voltage to the thermistor 104. The voltage regulator IC 102 ensures stable and consistent operation of the system 100 by providing a regulated output voltage to the thermistor 104. Many electronic components, such as the thermistor 104, require a specific voltage range for accurate and reliable operation. By regulating the input voltage 118 from the battery 120, the voltage regulator IC 102 ensures that the thermistor 104 receives a stable and consistent voltage supply, enabling accurate temperature sensing and minimizing potential errors or fluctuations caused by voltage variations.
Further, the thermistor 104 is placed inside the delivery box to sense the internal temperature of the delivery box. As the temperature increases, the resistance of the thermistor 104 decreases, resulting in a change in the voltage across the thermistor 104. The resulting voltage across the thermistor 104 corresponds to the sensed temperature inside the delivery box. The thermistor 104 also comprises the pre-defined reference voltage 108 that corresponds to the desired temperature inside the delivery box.
Further, placing the thermistor 104 inside the delivery box allows for direct and accurate temperature sensing of the environment where temperature control is needed. The thermistor's 104 ability to change its resistance based on temperature variations enables the system 100 to effectively monitor and respond to temperature changes within the delivery box. In addition, by incorporating the pre-defined reference voltage 108 corresponding to the desired temperature, the system 100 can compare the sensed temperature (through the thermistor's 104 voltage) with the target temperature range, enabling precise temperature regulation and maintenance of the desired conditions within the delivery box.
Furthermore, the comparator circuit 106 compares the resulting voltage from the thermistor 104 with a pre-defined reference voltage 108 corresponding to the desired temperature range for the delivery box. Based on the comparison of the resulting voltage and the reference voltage 108, the comparator circuit 106 generates a first signal, which is either a high or low output signal. In an implementation, the comparator circuit 106 is operated by the battery 120 and is configured to receive the input voltage 118 from the battery 120.
The comparator circuit 106 translates the temperature information from the thermistor 104 into the first signal that can be used for temperature control. By comparing the voltage from the thermistor 104 (representing the sensed temperature) with the pre-defined reference voltage (representing the desired temperature range), the comparator circuit 106 generates a high or low output signal. The high or low output signal serves as a trigger for the subsequent stages of the system 100, enabling the system 100 to take appropriate actions based on whether the sensed temperature is within or outside the desired range. The comparator circuit's 106 operation being powered by the battery 120 ensures that it can function independently and consistently, without being affected by potential fluctuations in external power sources.
In an embodiment, the system 100 further comprises an NTC (Negative Temperature Coefficient) sensor positioned within the delivery box and configured to provide feedback to the comparator circuit 106 for fine-tuning temperature control. The NTC sensor refers to a type of temperature sensor that works based on the principle of a decrease in electrical resistance of certain materials with an increase in temperature.
The inclusion of an NTC sensor within the delivery box provides an additional layer of temperature monitoring and feedback. By providing feedback to the comparator circuit 106, the NTC sensor allows for fine-tuning and precise temperature control within the delivery box. The NTC sensor's principle of decreasing resistance with increasing temperature complements the thermistor's 104 temperature sensing mechanism, enabling the system 100 to accurately detect and respond to temperature variations. Such an additional feedback loop enhances the overall temperature regulation capabilities of the system 100, ensuring that the desired temperature range is maintained with high accuracy and responsiveness.
Furthermore, the hysteresis circuit 112 is coupled to the comparator circuit 106. The hysteresis circuit 112 is configured to introduce hysteresis for low-to-high and high-to-low transitions of the first signal received from the comparator circuit 106. The hysteresis is done using positive feedback to control the transitions and maintain the pre-defined temperature range.
The incorporation of a hysteresis circuit 112 for low-to-high and high-to-low transitions of the signal received from the comparator circuit 106, is done to avoid rapid oscillations and instability in the temperature control process. The hysteresis creates an intentional delay or "lag" in the system's 100 response, preventing it from rapidly switching between heating and cooling modes when the sensed temperature is close to the desired setpoint. Such a positive feedback mechanism helps maintain the temperature within the pre-defined range in a stable and controlled manner, reducing the risk of overshooting or undershooting the target temperature.
In an embodiment, the hysteresis circuit 112 is configured to introduce a first setpoint for turning on the heater 114 and a second setpoint for turning off the heater 114, the second setpoint being higher than the first setpoint. The hysteresis circuit 112 sets different thresholds for turning on the heater 114 (low setpoint) and turning off the heater 114 (high setpoint), preventing rapid oscillations and providing stable temperature control inside the delivery box.
The use of different setpoints for turning on and turning off the heater 114 by the hysteresis circuit 112 is a practical implementation of the hysteresis. By introducing a lower setpoint for turning on the heater 114 and a higher setpoint for turning it off, system 100 creates a temperature "deadband" or hysteresis zone. The deadband prevents the system 100 from rapidly cycling between heating and cooling modes when the sensed temperature is close to the desired range, thus avoiding temperature oscillations and instability. The result is stable and consistent temperature control within the delivery box, ensuring that the temperature remains within the desired range without unnecessary fluctuations or overshoots, which can be detrimental to contents of the delivery box.
Further, the MOSFET 110 is coupled to the hysteresis circuit 112. The MOSFET 110 acts as a switch to control the conductivity and flow of electric current based on the first signal from the hysteresis circuit (112). When the first signal is high, the MOSFET 110 conducts, allowing current to flow; when the first signal is low, the MOSFET 110 does not conduct, cutting off the current flow.
The MOSFET 110 is helpful in high switching speed, low power consumption, and ability to handle high currents. By coupling the MOSFET 110 to the hysteresis circuit 112, the system 100 can efficiently and effectively control the flow of electric current to the heater 114 based on the first signal from the hysteresis circuit 112. When the first signal is high (indicating that heating is required), the MOSFET 110 conducts, allowing current to flow and activating the heater 114. Conversely, when the first signal is low (indicating that heating is not needed), the MOSFET 110 cuts off the current flow, preventing the heater 114 from operating. Th efficient switching mechanism enables precise control over the heating process, contributing to accurate temperature regulation within the delivery box.
The heater 114 is connected to the MOSFET 110. When the MOSFET 110 conducts, the MOSFET 110 allows current to flow through the heater 114, generating heat inside the delivery box. In addition, the at least one fan 116 is coupled to the heater 114 and is configured to circulate the heated air across the heater 114 and throughout the delivery box, ensuring even distribution of heat.
Moreover, the system 100 is configured to turn on or turn off the heater 114 based on the first signal from the hysteresis circuit 112. If the sensed temperature is below the low setpoint (determined by the hysteresis circuit 112), the heater 114 is turned on to raise the temperature inside the delivery box. Once the temperature reaches the high setpoint, the heater 114 is turned off to prevent further heating. The turn-on and turn-off cycle repeats as needed to maintain the internal temperature of the delivery box within the pre-defined desired temperature range.
In another embodiment, the system 100 includes a fuse arranged on the PCB 122. The fuse refers to a safety device, which is configured to protect electrical circuits from overcurrent, short circuits, and other electrical faults. Furthermore, the fuse is configured to protect the voltage regulator IC 102, the thermistor 104, and the comparator circuit 106 from overcurrent. Examples of the fuse may include, but are not limited to, a rewireable fuse, a cartridge fuse, a drop out fuse, a striker fuse, a switch fuse, and the like. The fuse is advantageous to prevent damage to the system 100 from overcurrent.
The system 100 may also be referred to as a Thermicube heater (or a hot keep) that is configured to keep the food items at a 60°C to 75°C temperature so that the food items placed inside the delivery box can remain hot. The system 100 is designed to considering all safety hazards in such a way that system 100 will not harm the quality of the food. The system 100 or the Thermicube heater uses a NTC as a sensor to sense the temperature of the delivery box (or a bag). After reaching the bag temperature up to 75°C, the MOSFET 110 arranged on the PCB 122 will cut off the heater 114 and the heater 114 starts cooling. As the temperature of the delivery box is down to 60°C, then the NTC will sense that temperature, and the MOSFET 110 will turn on the heater 114 so as to start heating the inner temperature of the delivery box.
In an implementation, the system 100 is configured to be operated at below mentioned conditions, such as with an input voltage of 12 Volt, input current of 9 Amp, and a power consumption of 92 watts. The heater 114 generates an electric current flowing into the coil, which transfers the electric energy into heat energy. Moreover, at least one fan 116 is mounted at an inlet of system 100, such as the at least one fan 116 is used for suction of atmospheric air and transferring it to system 100. The PCB 122 is used to mount electronic components on the board and the traces connect the components to form a working circuit or assembly.
FIG. 2 is a circuit diagram that depicts various electronics components of a printed circuit board (PCB) of a system, in accordance with another embodiment of the present disclosure. FIG. 2 is described in conjunction with elements from FIG. 1. With reference to FIG. 2, there is shown the PCB 122 includes the heater 114, the at least one fan 116 (i.e., the first fan 202 and the second fan 204), the voltage regulator IC 102, the comparator circuit 106, and the MOSFET 110.
The first fan 202 and the second fan 204 are positioned within the delivery box enclosure functioned to draw air into the enclosure and across the heat and facilitates the circulation of air, ensuring that the heat generated by the heater is evenly distributed throughout the delivery box. Furthermore, the first fan 202 and the second fan 204 helps in ensuring proper air circulation and heat distribution within the delivery box.
The PCB 122 further consist of the voltage regulator IC 102 configured regulates the voltage supplied by the battery to provide a stable output voltage, ensuring consistent power supply to other components on the PCB. Furthermore, the output of the voltage regulator IC 102 is connected to capacitors for input and output filtering which stabilize the voltage levels, reducing noise and fluctuations in the power supply. The output of the voltage regulator IC 102 is further given as an input to the comparator circuit 106 which allows the PCB to receive temperature readings from the thermistor. Moreover, the output of the comparator circuit 106 is connected to the gate of the MOSFET 110. Furthermore, the connection between the comparator circuit 106 and MOSFET 110 allows the comparator to control the conductivity of the MOSFET 110 based on the temperature readings, regulating the flow of current to the heater 114, the first fan 202 and the second fan 204. Additionally, the drain of the MOSFET 110 is connected to the heater 114, the first fan 202 and the second fan 204. Furthermore, the connection between the MOSFET 110, the heater 114, the first fan 202 and the second fan 204 to control the operation of the heater 114 and the plurality fans based on the temperature readings and system requirements.
By integrating the voltage regulator IC 102, the PCB 122 ensures a stable output voltage from the battery 120, providing consistent power to all components. Furthermore, the capacitors connected to the voltage regulator IC 102 filter the input and output voltage, reducing noise and fluctuations in the power supply. The connection between the voltage regulator IC 102 and the comparator circuit 106 allows precise temperature readings from the thermistor 104, enabling accurate temperature sensing, which helps to dynamically control the conductivity of the MOSFET 110, regulating the flow of current to the heater 114 and fans 116 based on the temperature readings. Consequently, the PCB 122 can effectively control the operation of the heater 114 and fans 116, optimizing temperature regulation and system performance. Overall, the configuration of the PCB 122 enhances the reliability and efficiency of the system 100, ensuring optimal operation and consistent temperature maintenance.
In an exemplary scenario, the integrated voltage regulator IC 102 within the PCB 122 ensures a steady output voltage from the battery 120, providing consistent power to all components of the storage unit. As the storage unit may be subject to external environmental factors or electrical disturbances, the capacitors linked to the voltage regulator IC 102 which can be a 7805 IC acts as a filter, smoothing out any fluctuations in the power supply, thus safeguarding the sensitive electronic components within the system 100. Furthermore, the connection between the 7805 IC and the comparator circuit 106 which can be LM358 IC accurately sense the temperature through the thermistor 104, facilitating precise temperature control. Consequently, the storage unit can efficiently maintain the desired temperature range, optimizing the preservation of perishable goods. Overall, the PCB 122 configuration significantly enhances the reliability and efficiency of the system 100, ensuring consistent temperature maintenance and prolonging the shelf life of stored items.
The circuit diagram represents various electronics components of a printed circuit board (PCB) 122 of the system 100. An exemplary information related to values of the electronics components, that is used during experimentation is given below:
Components
Value/Specifications
Resistor 10K, 2.2K, 100R, 30K
Capacitor 10uf/50v
Voltage Regulator 7805
Op-Amp LM358
Nichrome Wire 24 gauge, 1.33E resistance
MOSFET IRF540
NTC 10K
Diode 1N4007
FIG. 3 is a diagram that depicts an exploded view of a heater casing assembly, in accordance with another embodiment of the present disclosure. FIG. 3 depicts an exploded view of the heater casing assembly 300 that can be installed within the delivery box, such as to protect the system 100.
The heater casing assembly 300 comprises a first casing 302 and a second casing 304. The first casing 302 and the second casing 304 form an enclosure of the heater casing assembly 300. The first casing 302 and the second casing 304 act as a housing that contains all components and keeps the other components in place.
The heater casing assembly 300 comprises a heater mount 306 that is a component disposed within the enclosure formed by the first casing 302 and second casing 304. The purpose of the heater mount 306 is to securely hold and mount the heater 114 inside the heater casing assembly 300.
The heater 114 is the primary heating element in the system 100. The heater 114 is configured to generate heat and maintain the desired temperature within the delivery box. The heater 114 is received and mounted within the heater mount 306. The heater 114 comprises an outer tube made of SS-304 grade stainless steel, which is a food-grade material. Inside the outer tube, a nichrome wire is insulated with magnesium oxide (MgO). The nichrome wire is the heat generation component, while the MgO provides electrical insulation and allows only thermal energy to be transferred to the outer stainless-steel fins.
The at least one fan 116 is disposed within the enclosure formed by the first casing 302 and second casing 304. The at least one fan 116 is responsible for drawing air into the enclosure and circulating the air across the heater 114. The at least one fan 116 facilitates the transfer of heat from the heater 114 to the air inside the delivery box. In an example, the at least one fan 116 used is an inlet fan with dimensions of 50x15x50mm (LxWxH) and a flow rate of 18 CFM (cubic feet per minute).
The heater casing assembly 300 further comprises an upper cover 308 and a lower cover 310 that enclose the first casing 302 and the second casing 304, forming the complete enclosure of the heater casing assembly 300.
The PCB 122 is disposed of within the enclosure formed by the casings of the heater casing assembly 300. The PCB 122 provides electrical connections to the heater 114 and the fan 116, allowing them to receive power and control signals.
The heater casing assembly 300 comprises atleast one ceramic washer 312. The ceramic washer(s) 312 are configured to restrict heat flow from the heater mount 306 through conduction. The ceramic washer(s) 312 helps to reduce the temperature at the outer surface of the heater casing assembly 300, improving the overall efficiency of the system 100.
The heater casing assembly 300 further comprises a casing mount 314 that allows the entire heater casing assembly 300 to be securely mounted or fastened to another structure, such as the delivery box or bag where the food items are kept.
The integrated design of the heater casing assembly 300 allows for efficient heat generation by the heater 114, air circulation by the fan 116, and controlled heat transfer to maintain the desired temperature within the delivery box while minimizing heat loss to the exterior. Further, the heater casing assembly 300 protects the system 100 from exterior wear and tear.
FIG. 4 is a diagram that depicts a graphical illustration of a system for controlling temperature installed within a delivery box mounted on a vehicle, in accordance with another embodiment of the present disclosure. With reference to FIG. 4, there is shown a graphical illustration 400 depicting a system for controlling a temperature installed within the delivery box mounted in the vehicle, such as by depicting a temperature on x-axis 402A and time on y-axis 402B.
In an implementation scenario, the graphical illustration illustrates an experimental data of an experiment that was conducted in no load condition and the ambient temperature of the surrounding was 38°C. The temperature sensors were used to track the temperature and stopwatch was also used to measure the time (as depicted at x-axis 402A). Furthermore, the temperature and the time data are later verified by comparing it with Telematics Data. In an exemplary scenario, the experiment starts at 9:51am at an ambient temperature of 36°C and within a time of 20 minutes the temperature has reached a mark of 85°C, which shows the rise of 49°C temperature is attained within 20 minutes of the start of the experiment. After reaching 85°C the system gets cut-off easily and again starts at 82°C provides an average temperature in between 82-85°C. Therefore, the system 102 provides an efficient and improved heating in order to maintain a predefined temperature within the delivery box.
FIG. 5 is a flowchart of a method for controlling temperature within a delivery box, in accordance with another embodiment of the present disclosure. With reference to FIG. 5, there is shown a flow chart of a method 500 for the controlling the temperature within the delivery box. The method 500 includes steps 502 to 518.
At step 502, the method 500 includes receiving an input voltage 118. At step 504, the method 500 includes regulating the input voltage 118 to provide a regulated voltage. At step 506, the method 500 includes sensing, by a thermistor 104, an internal temperature of the delivery box and providing a reference voltage 108) corresponding to the sensed internal temperature. At step 508, the method 500 includes comparing, by a comparator circuit 106, the reference voltage 108 from the thermistor 104 with a pre-defined reference voltage corresponding to a desired temperature range. At step 510, the method 500 includes generating, by the comparator circuit 106, a first signal based on the comparison. At step 512, the method 500 includes introducing hysteresis, by a hysteresis circuit 112 coupled to the comparator circuit 106, for low-to-high and high-to-low transitions of the first signal using positive feedback to control the transitions and maintain the desired temperature range. At step 514, the method 500 includes controlling conductivity of a metal-oxide-semiconductor field-effect transistor (MOSFET) 110 based on the first signal from the hysteresis circuit 112. Furthermore, at step 516, the method 500 includes heating the delivery box by a heater 114 coupled to the MOSFET 110 and at step 518, the method 500 includes circulating air across the heater 114 within the delivery box using at least one fan 116 coupled to the heater 114. Moreover, the heater 114 is turned on or turned off based on the first signal from the hysteresis circuit 112 to maintain the internal temperature of the delivery box within the desired temperature range.
In an embodiment, introducing hysteresis includes setting a first setpoint for turning on the heater 114 and a second setpoint for turning off the heater 114, the second setpoint being higher than the first setpoint. The use of different setpoints for turning on and turning off the heater 114 by the hysteresis circuit 112 is a practical implementation of the hysteresis. By introducing a lower setpoint for turning on the heater 114 and a higher setpoint for turning it off, system 100 creates a temperature "deadband" or hysteresis zone. The deadband prevents the system 100 from rapidly cycling between heating and cooling modes when the sensed temperature is close to the desired range, thus avoiding temperature oscillations and instability. The result is stable and consistent temperature control within the delivery box, ensuring that the temperature remains within the desired range without unnecessary fluctuations or overshoots, which can be detrimental to contents of the delivery box.
In an embodiment, the method 500 further includes receiving the input voltage 118 from a battery management system (BMS) coupled to the voltage regulator IC 102. Coupling the BMS to the voltage regulator IC 102 ensures that the regulated voltage supplied to the other components of the system 100 is protected from potential voltage fluctuations or abnormal conditions. The BMS acts as a gatekeeper, providing the input voltage 118 to the voltage regulator IC 102 while also safeguarding the system 100 from short circuits and overcurrent situations.
Advantageously, the method 500 is used to provide a robust and an efficient temperature control mechanism for the delivery box to ensure precise temperature regulation within the desired range. Moreover, such temperature control mechanism is used to store food items and other items that require certain temperature range in order to attain their freshness or to prevent them from getting stale.
Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

,CLAIMS:We claim:
1. A system (100) for controlling temperature of a delivery box, comprising:
a voltage regulator integrated circuit (IC) (102) configured to regulate an input voltage (118) to provide a regulated 5V DC voltage;
a thermistor (104) configured to sense an internal temperature of the delivery box and provide a resulting voltage corresponding to the sensed temperature, wherein the thermistor (104) also comprises a reference voltage (108) corresponding to a desired temperature inside the delivery box;
a comparator circuit (106) configured to compare the reference voltage (108) from the thermistor (104) with a pre-defined reference voltage corresponding to a desired temperature range and generate a first signal based on the comparison;
a hysteresis circuit (112) coupled to the comparator circuit (106) and configured to introduce hysteresis for low-to-high and high-to-low transitions of the first signal using positive feedback to control such transitions in order to maintain the pre-defined temperature range;
a metal-oxide-semiconductor field-effect transistor (MOSFET) (110) coupled to the hysteresis circuit (112), wherein the MOSFET (110) is configured to control conductivity based on the first signal from the hysteresis circuit (112);
a heater (114) coupled to the MOSFET (110) and configured to provide heat to the delivery box; and
at least one fan (116) coupled to the heater (114) and configured to circulate air across the heater (114) within the delivery box;
wherein the system (100) is configured to turn on or turn off the heater (114) based on the first signal from the hysteresis circuit (112) to maintain the internal temperature of the delivery box within the pre-defined temperature range.
2. The system (100) as claimed in claim 1, wherein the hysteresis circuit (112) is configured to introduce a first setpoint for turning on the heater (114) and a second setpoint for turning off the heater (114), the second setpoint being higher than the first setpoint.
3. The system (100) as claimed in claim 1, further comprises a battery management system (BMS) coupled to the voltage regulator IC (102) and the comparator circuit (106) and configured to provide the input voltage (118) from a battery (120).
4. The system (100) as claimed in claim 1, further comprises a NTC sensor positioned within the delivery box and configured to provide feedback to the comparator circuit (106) for fine-tuning temperature control.
5. A method (500) for controlling temperature within a delivery box, the method (500) comprising:
receiving an input voltage (118);
regulating the input voltage (118) to provide a regulated voltage;
sensing, by a thermistor (104), an internal temperature of the delivery box and providing a resulting voltage corresponding to the sensed temperature, wherein the thermistor (104) also comprises a reference voltage (108) corresponding to a desired temperature inside the delivery box;
comparing, by a comparator circuit (106), the reference voltage (108) from the thermistor (104) with a pre-defined reference voltage corresponding to a desired temperature range;
generating, by the comparator circuit (106), a first signal based on the comparison;
introducing hysteresis, by a hysteresis circuit (112) coupled to the comparator circuit (106), for low-to-high and high-to-low transitions of the first signal using positive feedback to control the transitions and maintain the desired temperature range;
controlling conductivity of a metal-oxide-semiconductor field-effect transistor (MOSFET) (110) based on the first signal from the hysteresis circuit (112);
heating the delivery box by a heater (114) coupled to the MOSFET (110); and
circulating air across the heater (114) within the delivery box using at least one fan (116) coupled to the heater (114);
wherein the heater (114) is turned on or turned off based on the first signal from the hysteresis circuit (112) to maintain the internal temperature of the delivery box within the desired temperature range.
6. The method (500) as claimed in claim 5, wherein introducing hysteresis comprises setting a first setpoint for turning on the heater (114) and a second setpoint for turning off the heater (114), the second setpoint being higher than the first setpoint.
7. The method (500) as claimed in claim 5, further comprises receiving the input voltage (118) from a battery management system (BMS) coupled to the voltage regulator IC (102) and the comparator circuit (106).
8. A heater casing assembly (300) comprising:
a first casing (302) and a second casing (304) forming an enclosure;
a heater mount (306) disposed within the enclosure, the heater mount (306) configured to receive a heater (114), wherein the heater (114) is configured to heat a delivery box;
at least one fan (116) disposed within the enclosure and configured to draw air into the enclosure and across the heater (114);
an upper cover (308) and a lower cover (310) that enclose the first casing (302) and the second casing (304);
a printed circuit board (PCB) (122) disposed within the enclosure and configured to provide electrical connections to the heater (114) and the at least one fan (116);
at least one ceramic washer (312) configured to restrict heat flow from the heater mount (306); and
a casing mount (314) configured to secure the heater (114) casing assembly to another structure.
9. The heater casing assembly (300) as claimed in claim 8, wherein the at least one fan (116) comprises a first fan (202) and a second fan (204) disposed within the enclosure and configured to draw air into the enclosure and across the heater (114).
10. The heater casing assembly (300) as claimed in claim 8, wherein the heater mount (306) comprises a stainless-steel tube configured to receive the heater (114), the heater (114) comprising a nichrome wire insulated with magnesium oxide.