Low-temperature cng heating system for gas range extender and vehicle gas range extender assembly

Abstract

This invention relates to the field of gas range extenders, specifically a low-temperature CNG heating system for gas range extenders and a vehicle gas range extender assembly, including a heating unit and a piping unit connected to the gas range extender; the heating unit includes a primary heating unit and a secondary heating unit; both the primary and secondary heating units can heat low-temperature CNG; the primary heating unit is connected to the secondary heating unit through the piping unit; the secondary heating unit is connected to the intake manifold of the gas range extender; this invention, through the combined use of the two-stage heating system, can achieve rapid preheating of CNG fuel at low temperatures; the two-stage gradient heating adopts a graded mode of "primary coarse preheating water + secondary fine supplementary heating", avoiding the problems of excessive single-stage heating load and uneven temperature rise.

Description

Technical Field

[0001] This invention relates to the field of gas range extenders, specifically a low-temperature CNG heating system for gas range extenders and a gas range extender assembly for vehicles. Background Technology

[0002] Currently, most range-extended electric vehicles use gasoline engines, with a small number using CNG gas engines.

[0003] In extremely cold regions, CNG range extenders do not perform particularly well in cold starts, and their ignition performance at low temperatures is still inferior to that of gasoline.

[0004] Therefore, in order to improve the above problems, a device is needed to help achieve low-temperature start-up of CNG gas range extenders. Summary of the Invention

[0005] The purpose of this invention is to provide a low-temperature CNG heating system that can assist in the low-temperature start-up of a gas range extender.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A low-temperature CNG heating system for a gas range extender includes a heating unit and a piping unit connected to the gas range extender; the heating unit includes a primary heating unit and a secondary heating unit; both the primary and secondary heating units can heat the low-temperature CNG; the primary heating unit is connected to the secondary heating unit through the piping unit; the secondary heating unit is connected to the intake manifold of the gas range extender.

[0008] The primary heating unit is connected to the secondary heating unit via a valve body unit; the valve body unit can control the gas flow rate in the primary heating unit.

[0009] The primary heating unit includes a primary heater; the primary heater includes a heating body, which has a heating structure; the heating body has a flow chamber; one end of the heating body has a heating air inlet, and the other end has a heating air outlet; the heating air inlet is connected to the heating air outlet through the flow chamber; the secondary heating unit includes a secondary heater, which has an air inlet and an air outlet.

[0010] The circulation chamber has a labyrinthine structure.

[0011] The heating structure includes two heating plates, which are distributed opposite each other on opposite sides of the heating body; each heating plate can be used independently.

[0012] The piping unit includes a primary air intake pipe and a secondary air intake pipe; the primary air intake pipe is connected to the heating air inlet in the primary heating unit; one end of the secondary air intake pipe is connected to the heating air outlet in the primary heating unit, and the other end is connected to the air inlet in the secondary heating unit.

[0013] The low-temperature CNG heating system also includes a quick-connect structure; the quick-connect structure includes a female quick-connect structure and a male quick-connect structure, the male quick-connect structure being able to be inserted into the female quick-connect structure; a locking point and an O-ring are provided between the male quick-connect structure and the female quick-connect structure; the number of locking points is not less than two, and the number of O-rings is not less than three; a rubber sealing gasket is glued to the head of the male quick-connect structure, and the side of the rubber sealing gasket away from the male quick-connect structure is tightly fitted to the inner wall of the female quick-connect structure; the primary intake pipe and the primary heater, as well as the primary heater and the valve body unit, can all be connected via the quick-connect structure.

[0014] The low-temperature CNG heating system for the gas range extender also includes a control unit, which includes an HCU controller; the HCU controller is connected to the primary heating unit and the secondary heating unit.

[0015] A vehicle range extender assembly includes a gas range extender connected to a low-temperature CNG heating system; a secondary heating unit in the low-temperature CNG heating system is connected to the intake manifold of the gas range extender.

[0016] Each of the intake manifolds is connected to a secondary heating unit, and each secondary heating unit is connected to the primary heating unit through a valve body unit.

[0017] The advantages of this invention are:

[0018] The present invention discloses a low-temperature CNG heating system for a gas range extender.

[0019] This invention enables rapid preheating of CNG fuel gas at low temperatures through the combined use of a two-stage heating system.

[0020] Two-stage gradient heating: Employing a staged heating method of "first-stage coarse preheating + second-stage fine supplementary heating," this avoids the problems of excessive single-stage heating load and uneven temperature rise. Actual measurements show that after two-stage heating, the CNG gas temperature can be increased by more than 15°C relative to the ambient temperature, ensuring complete gas vaporization in extremely cold environments and improving ignition success rate.

[0021] The labyrinthine flow chamber inside the primary heater effectively extends the residence time of the low-temperature gas in the heating zone. Combined with the upper and lower double-sided PTC heating plates, it significantly improves the heat exchange efficiency, achieving small volume and high heat transfer.

[0022] Compared to the high cost of traditional gasoline-assisted starting systems, which can easily reach 800-1000 yuan, the cost of a single ceramic PTC heater is only about 20 yuan, significantly reducing the overall investment in the system. At the same time, its compact structure simplifies the production and procurement process, effectively saving manufacturing costs.

[0023] The secondary heater and HCU work in tandem for precise temperature control, effectively shortening the cold start preheating time. Based on a CFD flow rate and heating power model, the heater power and airflow temperature are adjusted in real time to achieve adaptive response to different operating conditions; this ensures stable engine ignition, optimizes gas thermal efficiency, and improves overall power output performance. The modular design reduces the complexity of the control system and facilitates maintenance and upgrades.

[0024] Compared to gasoline-assisted solutions, this invention eliminates the need for an additional fuel system, reducing vehicle weight and simplifying layout. It also eliminates the need for fuel lines and injection devices, reducing potential leakage risks and improving system reliability. The highly integrated electronic heating system reduces the vehicle's electrical load, offering both energy savings and safety advantages. It also facilitates stable ignition at low temperatures, reducing cold-start emissions and improving emissions in cold-weather regions.

[0025] This invention achieves rapid heating and stable ignition of CNG gas in extremely cold environments through the coordinated control of a two-stage electronically controlled PTC heater and an intelligent HCU. This invention is extremely low-cost, compact in structure, and simple to arrange, requiring no additional fuel system, reducing weight and electrical load, and effectively optimizing gas thermal efficiency and emission performance, thus offering both cost advantages and energy-saving and environmental benefits. Attached Figure Description

[0026] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0027] Figure 1 This is a schematic diagram of the overall structure of the vehicle range extender assembly of the present invention.

[0028] Figure 2 This is a simplified structural diagram of the secondary heater.

[0029] Figure 3 To improve the design of the quick-connect structure.

[0030] Figure 4 This is a simplified structural diagram of the first-stage heater.

[0031] Figure 5 This is a cross-sectional view of the heating element in the primary heater.

[0032] In the diagram: 1. Gas range extender, 2. Primary intake pipe, 3. Primary heater, 4. Gas switch valve, 5. Secondary intake pipe, 6. Secondary heater, 7. Intake manifold, 8. Heater control harness, 9. HCU controller, 10. Heater plug, 11. Heating module, 13. Quick-connect female terminal, 14. O-ring seal, 15. Locking point, 16. Rubber gasket, 17. Quick-connect male terminal. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0034] A low-temperature CNG heating system for a gas range extender 1 includes a heating unit and a piping unit connected to the gas range extender 1; the heating unit includes a primary heating unit and a secondary heating unit; both the primary and secondary heating units can heat low-temperature CNG; the primary heating unit is connected to the secondary heating unit through the piping unit; the secondary heating unit is connected to the intake manifold 7 of the gas range extender 1; the present invention, through the combined use of the two-stage heating system, can achieve rapid preheating of CNG gas at low temperatures.

[0035] Two-stage gradient heating: Employing a staged heating method of "first-stage coarse preheating + second-stage fine supplementary heating," this avoids the problems of excessive single-stage heating load and uneven temperature rise. Actual measurements show that after two-stage heating, the CNG gas temperature can be increased by more than 15°C relative to the ambient temperature, ensuring complete gas vaporization in extremely cold environments and achieving successful ignition on the first attempt.

[0036] The low-temperature CNG heating system for the gas range extender 1 disclosed in this invention mainly includes three parts: a heating unit, a pipeline unit, and the gas range extender 1; in essence, it adopts a two-stage series heating architecture, with the heating unit including a primary heating unit and a secondary heating unit.

[0037] The primary heating unit is located at the front end of the system and is the first heating stage after the cryogenic CNG gas enters. It integrates a labyrinthine flow chamber 311 and a double-sided heating plate (such as a ceramic PTC heating plate) for the initial preheating of the gas.

[0038] Secondary heating unit: Located at the rear of the system, close to the gas range extender 1. Each secondary heating unit has an independent intake manifold 7, used for secondary fine heating of the gas that has been preheated in the primary stage.

[0039] The piping unit includes a primary air intake pipe 2 and a secondary air intake pipe 5, which are used to connect the heating units at each stage to form a complete gas flow path.

[0040] The primary heating unit is connected in series with the secondary heating unit through a pipeline unit; the secondary heating unit is directly connected to the intake manifold 7 of the gas range extender 1 to ensure that the heated CNG gas directly enters the combustion chamber; the low-temperature CNG gas flows sequentially through: primary heating unit → pipeline unit → secondary heating unit → intake manifold 7 → combustion chamber of gas range extender 1.

[0041] Working principle: This system achieves efficient preheating of low-temperature CNG gas through staged heating, physical range extension, and optimized heat exchange. Its working principle is as follows:

[0042] In the first stage of preheating (rough heating), low-temperature CNG gas (the ambient temperature may be as low as -30°C) first enters the first heating unit; the gas flows meanderingly in the labyrinthine flow chamber 311, extending the residence time; the upper and lower double-sided heating plates work simultaneously, providing bidirectional heat radiation and heat conduction to the gas, achieving the first rapid temperature rise (temperature rise of about 5-10°C); the labyrinth design not only slows down the flow rate, but also increases the contact area between the gas and the heating wall, significantly improving the heat exchange efficiency.

[0043] In the secondary heating stage (fine heating), the gas that has been preheated in the first stage enters the secondary heating unit through a pipeline; the secondary heating unit heats the gas a second time, further increasing the gas temperature (the total temperature rise relative to the ambient temperature can reach about 15°C); at this time, the CNG gas has been fully vaporized, and the temperature meets the engine's cold start requirements.

[0044] After being heated during the intake combustion stage, the CNG gas enters the combustion chamber of the gas range extender 1 through the intake manifold 7; after mixing with air, it is stably ignited under the action of the spark plug, thus achieving a successful start-up of the engine on the first attempt.

[0045] Compared with existing technologies (such as single-stage heating, gasoline-assisted starting, etc.), this system has the following significant advantages:

[0046] High heating efficiency and reliable start-up; staged heating strategy: two-stage heating with clear division of labor, the first stage is responsible for rapid preheating, and the second stage is responsible for precise temperature replenishment, avoiding the problems of excessive load and uneven temperature rise in single-stage heating. Labyrinth-style flow channel design: extends gas residence time, increases heat exchange paths, achieves high-efficiency heating effect in small volume, and ensures complete gas vaporization and successful ignition on the first attempt in extremely cold environments.

[0047] Extremely low cost and good economic efficiency; low-cost PTC heating element: using ceramic PTC heating plate as the core heating element, the cost of a single heating unit is only tens of yuan, which is far lower than the traditional gasoline auxiliary starting system (which requires the addition of fuel tank, fuel pump, fuel line, etc., costing about 800-1000 yuan); no need for an additional fuel system: directly using CNG itself for heating, eliminating the need for a whole system of carrying and storing auxiliary gasoline, saving hardware procurement and maintenance costs from the source.

[0048] Compact structure and flexible layout; modular design: both heating and piping units use standardized interfaces, allowing for flexible configuration of the number of secondary heating units according to different displacements and cylinder numbers of range extenders (e.g., four independent secondary heaters for a four-cylinder engine). Space saving: eliminates the need for a fuel tank and related piping, reducing overall vehicle weight and simplifying layout within the limited space around the range extender.

[0049] Intelligent control, energy saving and environmental protection; HCU intelligent control interface available: The system has a reserved control interface that can be connected to an HCU (Hybrid Power Control Unit) to adjust heating power and duration in real time according to ambient temperature, achieving "on-demand heating" and avoiding energy waste. Reduced cold start emissions: By precisely increasing the intake air temperature, low-temperature combustion conditions are improved, resulting in more complete combustion of the air-fuel mixture and significantly reducing HC and CO emissions caused by incomplete combustion during the cold start phase.

[0050] The low-temperature CNG heating system for the gas range extender 1 disclosed in this invention achieves efficient and reliable start-up of the CNG range extender in low-temperature environments at extremely low cost through a two-stage series heating architecture and a labyrinth flow channel design. At the same time, it performs excellently in terms of structural compactness, safety, energy saving and environmental protection. It is an innovative technical solution with high cost performance and broad application prospects.

[0051] Furthermore, in this invention, the primary heating unit is connected to the secondary heating unit via a valve body unit; the valve body unit can control the gas flow rate in the primary heating unit; the valve body unit is essentially a flow control valve or regulating valve, mainly used to control the gas flow rate, and thus control the gas residence time in the primary heater 3.

[0052] The valve body unit is located between the primary heating unit and the secondary heating unit, and is connected to both via a piping unit. The core function of the valve body unit is to precisely control the gas flow rate from the primary heating unit. It can employ solenoid valves, proportional valves, or electronic throttle valves, adjusting the opening degree according to control commands to achieve on / off control or flow regulation of the flowing gas. During operation, the low-temperature CNG gas flows sequentially through: primary heating unit → valve body unit → secondary heating unit → intake manifold 7 → combustion chamber of gas range extender 1. The valve body unit is connected in series after the primary heating unit and before the secondary heating unit, forming a "heating-regulation-reheating" process. This system achieves efficient preheating and precise distribution of low-temperature CNG gas through the coordinated operation of staged heating and intermediate valve control. Its working principle is as follows:

[0053] In the first stage of preheating, low-temperature CNG gas enters the first stage heating unit, flows in a labyrinthine channel, and is heated by the upper and lower double-sided heating plates, achieving the first temperature rise (approximately 5-10℃).

[0054] During the flow control phase, the gas, after being preheated in the first stage, flows into the valve body unit. The valve body unit adjusts the gas flow in real time according to the engine operating conditions (such as starting, idling, and loading) and the cylinder demand. In the initial stage of cold start: the valve body is fully open to ensure that the maximum gas volume passes through the secondary heater 6 quickly, achieving rapid warm-up. In idling or low-load conditions: the valve body is partially closed to reduce the gas supply and avoid an overly rich mixture. At the same time, the reduction in the opening can also increase the residence time of the gas in the first-stage heater 3, thus optimizing the initial heating.

[0055] Through the design of the valve body unit, this invention achieves intelligent temperature control and flow management, which not only solves the problem of low-temperature start-up, but also enables precise management of gas supply under all operating conditions. It has significant advantages in combustion optimization, multi-cylinder uniformity, system safety and energy efficiency improvement.

[0056] In this invention, the primary heating unit includes a primary heater 3; the primary heater 3 includes a heating body 31, on which a heating structure is provided; a flow chamber 311 is provided inside the heating body 31; a heating inlet 34 is provided at one end of the heating body 31, and a heating outlet 35 is provided at the other end; the heating inlet 34 is connected to the heating outlet 35 through the flow chamber 311; the secondary heating unit includes a secondary heater 6, which has an inlet end 61 and an outlet end 62; the present invention discloses a low-temperature CNG heating system for a gas range extender 1. The core heating unit includes a primary heater 3 and a secondary heater 6. The primary heater 3 adopts an original structural design of double-sided heating and labyrinth flow channel: Heating body 31: as the base of the primary heater 3, the interior is hollow to form a gas flow space; it is essentially a flow pipe; heating inlet 34: located at one end of heating body 31, used to introduce low-temperature CNG gas; heating outlet 35: located at the other end of heating body 31, used to output preheated gas; flow chamber 311: located between heating inlet 34 and heating outlet 35, is the core area through which the gas flows.

[0057] In this invention, both the heating air inlet 34 and the heating air outlet 35 are connected to a quick-connect male terminal 17.

[0058] In this invention, the flow chamber 311 is required to be a labyrinthine structure; the flow chamber 311 is not a simple straight channel, but adopts a labyrinthine (detour-like) flow channel design; the flow channel is provided with multiple staggered baffles or protrusions, which force the gas to repeatedly turn and detour within the chamber; this design significantly prolongs the residence path and residence time of the gas in the heating area, while increasing the contact area between the gas and the heating wall.

[0059] Meanwhile, the heating structure described in this invention includes two heating plates 32, which are distributed opposite to each other on opposite sides of the heating body 31; the two heating plates 32 can be used independently; the first heating plate 32 is distributed on the upper side or one side of the heating body 31; the second heating plate 32 is distributed on the lower side or the opposite side of the heating body 31; the two heating plates 32 are distributed opposite to each other to form a bidirectional clamping heating of the flow chamber 311 from top to bottom (or left to right); each heating plate 32 can be controlled and used independently, and can be started simultaneously to achieve maximum heating power, or started on one side to achieve energy-saving heating.

[0060] Regarding the structure of the secondary heater 6: the secondary heater 6 has independent air inlet and air outlet; it integrates a heating module (such as a heating ceramic plate or PTC element) for secondary heating of the gas; the secondary heater 6 is located close to the intake manifold 7 to ensure that the heated gas enters the combustion chamber directly.

[0061] Low-temperature CNG gas enters the flow chamber 311 of the primary heater 3 through the heating inlet 34. The labyrinthine flow channel enhances heat exchange; the gas is forced to flow along a meandering path within the labyrinthine flow chamber 311, constantly changing its direction; each turn results in collisions and contact with the heating wall, forming forced convection heat transfer; the meandering design of the flow channel relatively reduces the gas velocity and prolongs the residence time, giving gas molecules more opportunities to absorb heat; the labyrinth structure significantly increases the effective heat exchange area, greatly improving the heat exchange efficiency per unit volume.

[0062] Dual-sided simultaneous heating mode: In extremely low temperature environments (such as below -30℃), both heating plates 32 are activated simultaneously, providing sandwich heating to the flow chamber 311 from both the top and bottom sides to achieve maximum heating power and rapidly increase the gas temperature; Single-sided independent heating mode: In relatively high ambient temperatures or during the maintenance phase after the engine has started, only one heating plate 32 can be activated as needed to achieve energy-saving operation; Thermal radiation + thermal conduction composite heating: The heating plate 32 not only heats the gas through thermal radiation, but also conducts heat to the gas through the metal wall of the heating body 31, forming a composite heating effect.

[0063] The secondary heater 6 provides fine heat replenishment; the gas, preheated in the first stage, enters the secondary heater 6; the secondary heater 6 reheats the gas a second time, further raising the gas temperature to the ideal starting value (the total temperature rise relative to the ambient temperature can reach about 15°C). The heated CNG gas enters the combustion chamber through the intake manifold 7, achieving stable ignition and start-up.

[0064] Enhanced heat transfer in labyrinth flow channels: Compared to straight-through flow channels, the labyrinth design extends gas residence time by 30%-50%, increases heat exchange area by more than 50%, and significantly improves heat exchange efficiency; Double-sided sandwich heating: The upper and lower heating plates 32 heat the flow channel simultaneously, forming a three-dimensional heating field, avoiding the problems of large temperature gradient and uneven heating caused by single-sided heating; Under the same power, the labyrinth double-sided heating structure can increase the gas temperature rise rate by more than 40%.

[0065] Dual-plate independent control: The two heating plates 32 can be started and stopped independently, realizing graded adjustment of heating power; On-demand heating capacity: The HCU controller 9 can flexibly select single-plate heating or dual-plate heating mode according to ambient temperature and engine operating conditions, optimizing energy consumption while ensuring heating effect; If one heating plate 32 fails, the other heating plate 32 can still maintain basic heating function, improving system reliability.

[0066] The labyrinthine flow channel achieves a longer gas flow within a limited volume, making the heater body compact and easy to arrange in the space around the range extender; the double-sided heating plate 32 is directly integrated into the heating body 31, requiring no additional installation space, and the overall structure is compact.

[0067] The gas repeatedly turns within the labyrinthine flow channel, generating turbulence and promoting the mixing of hot and cold airflows, thus avoiding local overheating or undercooling. Double-sided heating makes the temperature distribution on the flow channel cross-section more uniform, resulting in high consistency of outlet gas temperature, which is beneficial for uniform intake of each cylinder.

[0068] The PTC heating element features self-limiting temperature characteristics and rapid thermal response, heating up quickly upon energization without preheating. The labyrinthine flow channel's small-volume design shortens the gas residence time within the heater, resulting in a fast heating response that can adapt to real-time changes in engine operating conditions. The ceramic PTC heating element is inexpensive, and the total cost of the dual-plate design is still significantly lower than that of traditional fuel-assisted starting systems. The labyrinthine flow channel and double-sided independent heating plates 32 of the first-stage heater 3 are among the core innovations of this system. Through four key technologies—extended residence time, increased heat exchange area, bidirectional heat conduction, and independent power control—small-volume, high-efficiency, fast-response, and low-cost low-temperature CNG heating is achieved, providing a fundamental guarantee for the reliable starting of the gas range extender 1 in extremely cold environments.

[0069] Furthermore, the pipeline unit in this invention includes a primary air intake pipe 2 and a secondary air intake pipe 5; the primary air intake pipe 2 is connected to the heating air inlet 34 in the primary heating unit; one end of the secondary air intake pipe 5 is connected to the heating air outlet 35 in the primary heating unit, and the other end is connected to the air inlet in the secondary heating unit; the primary air intake pipe is located at the front end of the system, connecting the gas source and the primary heating unit; one end is connected to a low-temperature CNG gas source (such as a CNG cylinder or pressure reducing valve), and the other end is connected to the heating air inlet 34 of the primary heating unit; it is responsible for transporting the unheated low-temperature CNG gas to the primary heater 3 for initial preheating.

[0070] The secondary air inlet pipe is located between the primary heating unit and the secondary heating unit; one end is connected to the heating outlet 35 of the primary heating unit; the other end is connected to the air inlet of the secondary heating unit; it is responsible for transporting the gas preheated in the primary heater 3 to the secondary heater 6 for secondary heating.

[0071] Gas flow path: Gas source → First-stage intake pipe → First-stage heater 3 → Second-stage intake pipe → Second-stage heater 6 → Intake manifold 7.

[0072] In this invention, each pipe and each heating unit are connected by a quick-connect structure, which facilitates assembly and maintenance.

[0073] The first-stage intake pipe is the inlet channel for cryogenic gas. During the initial stage of cold start, the ambient temperature is extremely low (possibly below -30°C), and CNG gas enters the first-stage intake pipe in a cryogenic state. As the inlet channel for cryogenic gas, the inner wall of the first-stage intake pipe is in direct contact with the cryogenic gas. To reduce heat loss, the first-stage intake pipe can be insulated (e.g., covered with heat-insulating material) to prevent the gas from absorbing ambient heat or causing the pipeline to freeze before entering the heater.

[0074] Secondary intake pipe: The channel for transporting preheated gas; the gas temperature has been increased by 5-10℃ after being preheated by the primary heater 3, and is transported to the secondary heater 6 through the secondary intake pipe; the secondary intake pipe undertakes the task of transporting high-temperature gas, and its material must withstand a certain temperature and maintain structural strength; the length and direction of the secondary intake pipe should be designed to minimize heat loss and ensure that the preheating effect is not significantly reduced due to pipeline transport.

[0075] This invention establishes a complete airflow channel for "low-temperature introduction and preheating delivery" through the clear division of labor and coordinated operation of the primary and secondary air intake pipes. Combined with quick-connect fittings and insulation design, it minimizes heat loss while ensuring high-pressure sealing safety, providing reliable physical support for the efficient operation of the two-stage heating system. This structural design gives the system excellent layout flexibility, ease of maintenance, and multi-cylinder expansion capabilities.

[0076] Furthermore, the low-temperature CNG heating system of this invention also includes a quick-connect structure; the quick-connect structure includes a female quick-connect structure 13 and a male quick-connect structure 17, the male quick-connect structure 17 being able to be inserted into the female quick-connect structure 13; a locking point 15 and an O-ring seal 14 are provided between the male quick-connect structure 17 and the female quick-connect structure 13; the number of locking points 15 is not less than two, and the number of O-ring seals 14 is not less than three; a rubber sealing gasket 16 is glued to the head of the male quick-connect structure 17, and the side of the rubber sealing gasket 16 away from the male quick-connect structure 17 is tightly fitted to the inner wall of the female quick-connect structure 13; The primary intake pipe 2 and the primary heater 3, as well as the primary heater 3 and the valve body unit, can all be connected via a quick-connect structure. The quick-connect structure is a key component in this invention for achieving rapid and reliable connection between modules, and consists of a male end, a female end, and multiple sealing and protection mechanisms. The quick-connect structure disclosed in this invention mainly includes a male end 17: the male end 17 is an insertion end, connected to the intake or exhaust end of components such as the primary heater 3; the female end 13 is a receiving end, connected to another component corresponding to the male end 17, and the female end 13 has an insertion cavity inside to accommodate the male end; the male end is movably inserted into the female end to form a detachable quick connection.

[0077] Locking points 15: Set between the male and female ends, with no fewer than two; after the male end is inserted into place, the locking points 15 automatically engage to prevent the male end from coming out due to vibration or high-pressure airflow impact; they can be arranged circumferentially or axially at intervals to form multi-point locking and improve pull-out resistance.

[0078] O-rings 14 are disposed between the male end and the female end, with no fewer than three; they are spaced apart along the axial direction to form multiple sealing barriers; after the male end is inserted, the O-rings are compressed between the outer wall of the male end and the inner wall of the female end to form a radial seal; the material is generally a rubber material that is resistant to low temperature and gas corrosion (such as fluororubber, EPDM rubber).

[0079] The rubber sealing gasket 16 is glued to the head of the male end 17 of the quick-connect structure; after the male end is fully inserted, the side of the rubber sealing gasket 16 away from the male end is tightly fitted with the inner wall of the female end 13 of the quick-connect structure; as an auxiliary seal at the end, it provides additional sealing protection in the event of O-ring failure or high pressure impact.

[0080] In this invention, the primary intake pipe and the primary heater 3 are connected by a quick-connect structure; the primary heater 3 and the valve body unit are connected by a quick-connect structure; other connection points that require quick assembly and disassembly can adopt the same structure.

[0081] When using the quick-connect structure, align the male end 17 of the quick-connect structure with the insertion hole of the female end and push it in axially. The head of the male end first compresses the rubber sealing gasket 16, making it fit tightly against the inner wall of the female end. Continue pushing until the locking point 15 on the male end aligns with the groove in the female end. The locking point 15 automatically pops into the groove, making a "click" sound to indicate that it is in place. Two or more locking points 15 engage simultaneously to form an axial lock, preventing the male end from loosening. First seal (O-ring group): After the male end is inserted, the three O-rings 14 are compressed in sequence, forming multiple radial sealing rings between the outer wall of the male end and the inner wall of the female end, blocking the path of gas leakage along the axial direction. Second seal (rubber sealing gasket 16): The rubber sealing gasket 16 at the head of the male end fits tightly against the end face or inner conical surface of the inner wall of the female end, forming an auxiliary end face seal. Even if the O-rings completely fail, the sealing gasket can still prevent gas leakage. Sealing synergy effect: The O-rings undertake the main sealing task, and the rubber gasket serves as a backup. Together, they constitute a redundant sealing system.

[0082] During disassembly, use a special tool to press the locking point 15 release mechanism to disengage the locking point from the slot; pull out the male end axially, and the rubber sealing gasket 16 separates from the female end; the O-ring exits with the male end, and the connection is released.

[0083] This invention employs a quadruple seal with three O-rings and end-face rubber gaskets, far exceeding the sealing level of ordinary quick-connect couplings (typically 1-2 seals), ensuring zero leakage of high-pressure CNG gas. Even if one O-ring fails due to aging or damage, the remaining sealing structures still guarantee airtightness, greatly reducing the risk of leakage. Through the synergistic effect of multiple physical seals and multi-point mechanical locking, this invention achieves four core performance characteristics: zero leakage, resistance to detachment, quick assembly / disassembly, and long service life, providing a reliable foundation for the entire cryogenic heating system. This structural design not only enhances the safety and reliability of the system but also significantly optimizes the convenience of production assembly and after-sales maintenance.

[0084] Furthermore, the low-temperature CNG heating system for the gas range extender 1 described in this invention also includes a control unit, which comprises an HCU controller 9. The HCU controller 9 is connected to the primary heating unit and the secondary heating unit. The introduction of the HCU controller 9 in this invention forms an intelligent temperature control system. Through precise environmental perception, model-based control strategies, closed-loop feedback adjustment, and collaborative operation with the entire vehicle, the HCU not only ensures the successful start-up rate of the CNG range extender in extremely cold environments but also achieves advanced functions such as on-demand heating, minimum energy consumption, fault self-diagnosis, and continuous optimization, which is the core embodiment of the intelligent level of this invention.

[0085] HCU Controller 9 is the Hybrid Control Unit, serving as the core control module for the entire vehicle or range extender. It integrates a microprocessor, storage chip, input / output interfaces, and communication module; and has a pre-set control algorithm model, including a temperature-power mapping table, PID control parameters, fault diagnosis logic, etc.

[0086] Connection between HCU controller 9 and primary heating unit: connected to the two heating plates 32 (upper heating plate 32 and lower heating plate 32) of primary heater 3 respectively through heater control harness; Connection between HCU controller 9 and secondary heating unit: connected to the heating module of secondary heater 6 through heater control harness; Waterproof connectors are used to ensure electrical reliability in the harsh environment of engine compartment.

[0087] Signal types include power drive signals (PWM waves or switching signals) and temperature feedback signals (heater built-in temperature sensor).

[0088] The HCU controller 9 is also connected to an ambient temperature sensor (or utilizes an existing intake air temperature sensor); optionally, a gas temperature sensor (installed at the outlet of the secondary heater 6 or the intake manifold 7) is connected for closed-loop control; optionally, engine status signals (such as crankshaft position, speed, load, etc.) are connected for operating condition identification.

[0089] Actuator output; Primary heater 3 control: can independently control the start / stop and power of the upper heating plate 32 and the lower heating plate 32; Secondary heater 6 control: controls the start / stop and power of the secondary heater 6; HCU simultaneously controls the opening degree of the valve body unit.

[0090] The HCU controller 9 collects the ambient temperature (or intake air temperature) in real time; it compares the collected temperature with the internally preset low temperature start-up threshold (such as -10℃, -20℃); when the ambient temperature is lower than the set threshold, the HCU determines that the heating system needs to be started and enters the cold start heating mode.

[0091] The HCU determines the target heating temperature and heating duration by looking up a table in the preset model based on the ambient temperature. For example, the target temperature rise is 15℃ at -30℃, 10℃ at -20℃, and 5℃ at -10℃. At the same time, it determines the power allocation for the primary / secondary heating stages and the start / stop strategy (single or double plate) for the primary heater's three dual plates.

[0092] Primary heating control: The HCU sends a control signal to the primary heater 3: In extremely cold conditions (e.g., <-25℃): both upper and lower heating plates are activated simultaneously for full-power heating and rapid preheating; in general low-temperature conditions (-15℃ to -25℃): a single heating plate (e.g., the upper plate) is activated for medium-power operation and energy-saving insulation; in slightly cold conditions (-5℃ to -15℃): a single heating plate is activated for low-power or intermittent operation. If the primary heater 3 has a built-in temperature sensor, the HCU can receive real-time temperature feedback, forming a closed-loop control for precise power adjustment.

[0093] Secondary heating control; The HCU sends a control signal to the secondary heater 6, which typically employs a full-power rapid heating strategy; The goal of secondary heating is to precisely raise the gas temperature to the required starting value (e.g., -15°C); If a temperature sensor is installed at the outlet of the secondary heater 6 or in the intake manifold 7, the HCU can achieve precise closed-loop control to prevent overheating or underheating.

[0094] Timing coordination control; preheating sequence: the HCU controls the first-stage heater 3 to start first, and then starts the second-stage heater 6 after a certain delay (such as 10-30 seconds), so that the two-stage heating works in coordination;

[0095] Start-stop sequence: After the engine starts successfully, the HCU gradually reduces the heating power or shuts down the heater according to the operating conditions;

[0096] Fault protection: If a short circuit, open circuit, or overheating is detected in the heater, the HCU will immediately cut off the power supply to the corresponding heater and report a fault code.

[0097] A vehicle range extender assembly includes a gas range extender 1 connected to a low-temperature CNG heating system. A secondary heating unit in the low-temperature CNG heating system is connected to the intake manifold 7 of the gas range extender 1. Each intake manifold 7 is connected to a secondary heating unit, and each secondary heating unit is connected to a primary heating unit via a valve body unit. The range extender assembly disclosed in this invention achieves independent and precise control of the intake air temperature of each cylinder through a distributed heating architecture of "primary centralized preheating + independent secondary heating before each cylinder." This solution not only solves the starting problem in low-temperature environments but also significantly improves the starting smoothness, operational stability, and overall reliability of the multi-cylinder gas range extender 1 through cylinder heating uniformity assurance, flexible control strategies, and optimized energy efficiency. Combined with quick-connect fittings and HCU intelligent control, it constitutes a complete, advanced, and practical low-temperature starting solution.

[0098] The vehicle range extender assembly disclosed in this invention includes a gas range extender 1 body integrated with a low-temperature CNG heating system, and adopts a distributed heating architecture of "first-stage centralized preheating and heating + second-stage independent heating": the gas range extender 1 is an internal combustion engine that uses CNG (compressed natural gas) as fuel for power generation in hybrid vehicles; it has multiple cylinders (such as three-cylinder or four-cylinder), each cylinder corresponding to an independent intake manifold 7; the intake manifold 7 is responsible for introducing the combustible mixture into the combustion chamber of each cylinder.

[0099] The low-temperature CNG heating system includes a primary heating unit, a valve body unit, a secondary heating unit, and a piping unit. The primary heating unit adopts a labyrinthine flow channel + double-sided PTC heating plate 32 structure to centrally preheat the total intake air. The valve body unit is located between the primary heating unit and each secondary heating unit and is responsible for airflow distribution and flow control. The secondary heating units are configured one-to-one, with each intake manifold 7 independently connected to a secondary heater 6. The piping unit includes a primary intake pipe (from the air source to the primary heater 3) and a secondary intake pipe (from the primary heater 3 to each secondary heater 6).

[0100] The primary heating unit is located at the front end of the system and receives low-temperature CNG from the gas cylinder. The outlet of the primary heating unit is connected to the inlet of the valve body unit through a pipe. The outlet of the valve body unit is divided into multiple paths, each connected to the inlet of the secondary heating unit through an independent secondary inlet pipe. The outlet of each secondary heating unit is directly connected to the intake manifold 7 of the corresponding cylinder. The HCU controller 9 is electrically connected to the primary heater 3, each secondary heater 6, and the valve body unit. The HCU can independently control the start / stop and power of each secondary heater 6. The HCU can control the total flow rate or the flow rate of each branch of the valve body unit.

[0101] The low-temperature CNG gas first enters the primary heating unit and is heated by the double-sided heating plate 32 in the labyrinthine flow channel; the primary heater 3 preheats all the gas that is about to enter each cylinder uniformly to achieve a basic temperature rise (5-10℃); this stage solves the temperature threshold for raising the gas from extremely low temperature to a temperature that can be further heated.

[0102] Flow distribution and control; preheated gas enters the valve body unit; the valve body unit distributes the airflow to the corresponding secondary heater 6 of each cylinder according to the HCU command; the valve body unit can have total flow regulation function or branch independent regulation function: total flow regulation: adjust the valve body opening according to the total air demand of the engine; branch independent regulation: independently control the air volume of each cylinder to compensate for the differences in intake manifold 7 of each cylinder.

[0103] The gas is independently preheated and distributed to each cylinder before entering the corresponding secondary heater 6. Each secondary heater 6 independently reheats the gas about to enter its cylinder. The secondary heater 6 can perform differentiated heating according to the actual needs of the cylinder (e.g., cylinders closer to the exhaust pipe can be heated less, and cylinders farther away can be heated more). This ensures that the temperature of the gas entering each cylinder reaches a consistent and optimal starting value (total temperature rise of about 15°C).

[0104] Uniform heating of each cylinder is guaranteed; independent secondary heating: each cylinder has its own dedicated secondary heater 6, which can independently adjust the heating power according to the actual needs of the cylinder; eliminate inherent differences: it can compensate for the temperature differences between cylinders caused by different intake manifold length, position and heat dissipation conditions.

[0105] Improve the smoothness of multi-cylinder engine starting; ensure that the gas temperature of each cylinder is as consistent as possible, and ensure that the ignition time and combustion rate of each cylinder are similar to avoid starting vibration caused by misfire of individual cylinders; after starting, the combustion of each cylinder is uniform, the idle speed fluctuates little, and the engine runs smoothly; avoid problems such as incomplete combustion and increased carbon deposits caused by overcooling of individual cylinders.

[0106] For cylinders that dissipate heat quickly (such as end cylinders or cylinders near the cooling water passage), the secondary heating power can be increased; for cylinders that dissipate heat slowly, the heating power can be reduced.

[0107] Example:

[0108] Reference Figures 1 to 4 A low-temperature start heating system for a CNG range extender 1 is disclosed, which is a technical research and development design developed from the perspective of solving practical low-temperature cold start. The CNG range extender 1 is existing technology, and its specific structural design will not be described in detail here. The input end of the CNG range extender 1 is connected to an intake manifold 7. The end of the intake manifold 7 away from the CNG range extender 1 is connected to a secondary heater 6, which is used to heat the CNG gas a second time. The end of the secondary heater 6 away from the intake manifold 7 is connected to a secondary intake pipe 5. The end of the secondary intake pipe 5 away from the secondary heater 6 is connected to a gas switch valve 4. The input end of the gas switch valve 4 is connected to a primary heater 3, which is used to heat the CNG gas for the first time. The end of the primary heater 3 away from the gas switch valve 4 is connected to a primary intake pipe 2. The low-temperature CNG gas sequentially enters the combustion chamber of the CNG range extender 1 through the primary intake pipe 2, the primary heater 3, the gas switch valve 4, and the intake manifold 7 for combustion.

[0109] The primary heater 3 has a sandwich-like structure design. The upper layer is a ceramic PTC heating plate, the middle layer is a gas heating labyrinth layer, and the lower layer is a ceramic PTC heating plate. Both the upper and lower ceramic PTC heating plates are connected to positive and negative electricity respectively, heating the gas heating labyrinth layer from both sides simultaneously. The gas heating labyrinth layer has an inlet and an outlet. The internal labyrinth design is used to slow down the CNG gas flow rate, improve the heat transfer level of the upper and lower heating plates 32, and quickly increase the temperature, thereby achieving full heating of CNG gas. It is also easy to install and maintain.

[0110] The secondary heater 6 is an existing technology that uses mainstream mass-produced heaters to reduce system costs and enable rapid application. Its structure includes a heater plug 10 and a heating module 11. The heating module 11 generally uses heating ceramic plates to heat the flowing low-temperature gas.

[0111] The CNG gas temperature can be increased by 5 to 10 degrees Celsius after passing through the primary heater 3, and after passing through the secondary heater 6, its temperature can be increased by about 15 degrees Celsius relative to the ambient temperature. At this point, the CNG gas temperature meets the start-up requirements.

[0112] The CNG gas range extender 1 is equipped with an HCU controller 9 on one side. The HCU controller 9 is existing technology and is connected to the primary heater 3 and the secondary heater 6 through the heater control harness 8. The HCU controller 9 is used to collect ambient temperature and control the start-up and shutdown of the primary heater 3 and the secondary heater 6 according to the pre-set model limit value. At the same time, it controls the start-up time and shutdown time to control the heating duration and heating temperature, thereby realizing intelligent control.

[0113] The primary intake pipe 2, primary heater 3, gas switch valve 4, and secondary intake pipe 5 are all connected to each other via quick-connect structures. Each quick-connect structure includes a female end 13 and a male end 17. The female end 13 and male end 17 are movably connected to their respective devices. The male end 17 is movably inserted into the female end 13. Locking points 15 and O-rings 14 are provided between the male end 17 and the female end 13. The locking points 15 protect the high-pressure CNG, and there are at least two of them. The O-rings 14 ensure airtightness, and there are at least three of them. To further ensure airtightness, a rubber sealing gasket 16 (as shown in the attached image) is glued to the head of the male end 17. Figure 3 As shown), the side of the rubber sealing gasket 16 away from the male end 17 of the quick-connect structure is tightly fitted to the inner wall of the female end 13 of the quick-connect structure.

[0114] When using this invention, the first-stage intake pipe 2, the first-stage heater 3, the gas switch valve 4, and the second-stage intake pipe 5 are connected sequentially through a quick-connect structure. Then, the HCU controller 9, the first-stage heater 3, and the second-stage heater 6 are started. Based on the actual ambient temperature and the specific engine power requirements, a simulation model is established in the HCU controller 9 to ensure that the required temperature of the range extender is accurately met.

[0115] Next, the low-temperature CNG gas is introduced into the first-stage heater 3 through the first-stage intake pipe 2. After the HCU model signal is controlled, the first-stage heating power and time are regulated. The first-stage heater 3 raises the CNG gas temperature by 5 to 10 degrees Celsius. The heated CNG gas enters the gas switching valve 4 to wait for distribution to the four cylinders.

[0116] Secondly, the CNG gas enters the secondary heater 6 through the secondary intake pipe 5 for secondary heating. After secondary heating, the temperature of the CNG gas can be increased by about 15 degrees Celsius relative to the ambient temperature, at which point the temperature is suitable for startup.

[0117] Finally, CNG gas enters the intake manifold 7, and then follows the opening of the valve of the CNG range extender 1 to enter its combustion chamber for combustion, thus achieving a cold start for the CNG range extender 1.

[0118] 1. This invention achieves rapid preheating of CNG fuel at low temperatures by introducing multi-stage electronically controlled PTC heaters. Compared with the high cost of traditional gasoline-assisted starting systems (often 800-1000 yuan), the cost of each of the five newly added ceramic PTC heaters is only about 20 yuan, significantly reducing the overall system investment. At the same time, the compact structure simplifies the production and procurement process, effectively saving manufacturing costs.

[0119] 2. The two-stage heating system works in conjunction with the HCU's precise temperature control, effectively shortening the cold start preheating time. Based on a CFD flow rate and heating power model, the heater power and airflow temperature are adjusted in real time to achieve adaptive response to different operating conditions; this ensures stable engine ignition, optimizes gas thermal efficiency, and improves overall power output performance. The modular design reduces the complexity of the control system and facilitates maintenance and upgrades.

[0120] 3. Compared to gasoline-assisted solutions, this device eliminates the need for an additional fuel system, reducing overall vehicle weight and simplifying layout. It also eliminates the need for fuel lines and injection devices, reducing potential leakage risks and improving system reliability. The highly integrated electronic heating system reduces energy consumption and vehicle electrical load, offering both energy-saving and safety advantages. It also facilitates stable ignition at low temperatures, reducing cold-start emissions and improving emissions in cold regions.

[0121] In summary, this invention achieves rapid heating and stable ignition of CNG gas in extremely cold environments through the coordinated control of a two-stage electronically controlled PTC heater and an intelligent HCU. This solution is extremely low-cost, compact, and simple to arrange, requiring no additional fuel system, reducing weight and electrical load, and effectively optimizing gas thermal efficiency and emission performance, thus offering both cost advantages and energy-saving and environmental benefits.

[0122] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A low-temperature CNG heating system for a gas range extender, characterized in that... This includes the heating unit and piping unit connected to the gas range extender; The heating unit includes a primary heating unit and a secondary heating unit; Both the primary heating unit and the secondary heating unit can heat low-temperature CNG; The primary heating unit is connected to the secondary heating unit via a piping unit; the secondary heating unit is connected to the intake manifold of the gas range extender.

2. The low-temperature CNG heating system for a gas range extender according to claim 1, characterized in that... The primary heating unit is connected to the secondary heating unit via a valve body unit; the valve body unit can control the gas flow rate in the primary heating unit.

3. A low-temperature CNG heating system for a gas range extender according to any one of claims 1-2, characterized in that... The primary heating unit includes a primary heater; the primary heater includes a heating body, and the heating body is provided with a heating structure; the heating body is provided with a flow chamber; one end of the heating body is provided with a heating air inlet, and the other end is provided with a heating air outlet; the heating air inlet is connected to the heating air outlet through the flow chamber; the secondary heating unit includes a secondary heater, and the secondary heater is provided with an air inlet end and an air outlet end.

4. A low-temperature CNG heating system for a gas range extender according to claim 3, characterized in that... The flow chamber has a labyrinthine structure.

5. A low-temperature CNG heating system for a gas range extender according to claim 3, characterized in that... The heating structure includes two heating plates, which are distributed opposite each other on opposite sides of the heating body; the two heating plates can be used independently.

6. A low-temperature CNG heating system for a gas range extender according to claim 1, characterized in that... The pipeline unit includes a primary air intake pipeline and a secondary air intake pipeline; the primary air intake pipeline is connected to the heating air inlet in the primary heating unit; one end of the secondary air intake pipeline is connected to the heating air outlet in the primary heating unit, and the other end is connected to the air inlet in the secondary heating unit.

7. A low-temperature CNG heating system for a gas range extender according to claim 6, characterized in that... The low-temperature CNG heating system also includes a quick-connect structure; the quick-connect structure includes a female quick-connect structure and a male quick-connect structure, the male quick-connect structure being able to be inserted into the female quick-connect structure; a locking point and an O-ring are provided between the male quick-connect structure and the female quick-connect structure; the number of locking points is not less than two, and the number of O-rings is not less than three; a rubber sealing gasket is glued to the head of the male quick-connect structure, and the side of the rubber sealing gasket away from the male quick-connect structure is tightly fitted to the inner wall of the female quick-connect structure; the primary intake pipe and the primary heater, as well as the primary heater and the valve body unit, can all be connected via the quick-connect structure.

8. A low-temperature CNG heating system for a gas range extender according to claim 1, characterized in that... The low-temperature CNG heating system for the gas range extender also includes a control unit, which includes an HCU controller; the HCU controller is connected to the primary heating unit and the secondary heating unit.

9. A vehicle range extender assembly, characterized in that, Includes a gas range extender, the gas range extender being connected to a low-temperature CNG heating system as described in any one of claims 1-8; a secondary heating unit in the low-temperature CNG heating system is connected to the intake manifold of the gas range extender.

10. A vehicle range extender assembly according to claim 9, characterized in that, Each of the intake manifolds is connected to a secondary heating unit, and each secondary heating unit is connected to the primary heating unit through a valve body unit.

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