Stirling waste heat recovery system for a hybrid commercial vehicle

Abstract

The utility model discloses a kind of Stirling waste heat recovery systems for hybrid commercial vehicles, including hybrid power engine, Stirling engine and generator, exhaust pipe is arranged between the hybrid power engine and Stirling engine, the inlet end of the exhaust pipe is communicated with the outlet end of the hybrid power engine, the outlet end of this exhaust pipe is communicated with the expansion chamber of Stirling engine, the end of Stirling engine away from expansion chamber is connected with the input end of the generator, the output end of this generator is connected with electric air pump, the electric air pump is communicated with the exhaust pipe close to one end of hybrid power engine by adjusting pipeline.The system compared with other commercial vehicles containing waste heat recovery system, structure is more simple, easy to arrange and control of whole vehicle, thermoelectric conversion efficiency is higher;The system compared with other commercial vehicles not containing waste heat recovery system, effectively recycles and utilizes the exhaust waste heat of hybrid engine, improves whole vehicle fuel efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of automotive exhaust waste heat recovery systems, specifically to a Stirling waste heat recovery system for hybrid commercial vehicles. Background Technology

[0002] In 2023, the China Society of Automotive Engineers launched the "Technical Roadmap for Energy-Saving and New Energy Vehicles". Figure 3 The revised and upgraded version .0 emphasizes the transformation of the automotive industry and the construction of an emerging industrial ecosystem guided by "green and low-carbon, intelligent connectivity, and digital integration." The roadmap points out that during 2025-2030, technological upgrades and optimizations will be carried out on powertrain technologies such as high-efficiency hybrid powertrains for commercial vehicles and the integration of engine waste heat recovery, in order to achieve the goal of achieving internationally leading levels of vehicle fuel consumption.

[0003] During the operation of hybrid commercial vehicles, components such as the engine and motor generate a significant amount of waste heat. If this energy is not utilized, it will result in energy waste and thermal pollution. With the advancement of high-efficiency hybrid engines, approximately 40-50% of the chemical energy generated by fuel combustion can be converted into effective work output, 15-20% is carried away by cooling water, and 30-40% is discharged as exhaust gas. Since engine exhaust temperature is much higher than cooling water temperature, fully utilizing this waste heat will significantly improve fuel efficiency. While waste heat recovery technology has been successfully applied in some fields, it is still in the exploratory research stage in the field of hybrid commercial vehicles. Furthermore, commercial vehicle users are highly sensitive to the overall operating cost of the vehicle; therefore, effectively improving fuel efficiency has become crucial for developers of commercial vehicles. Thus, it is necessary to design and develop feasible waste heat recovery systems for hybrid commercial vehicles to maximize energy utilization.

[0004] From the perspective of total energy efficiency, waste heat recovery is the most direct means of energy saving in internal combustion engines. Therefore, waste heat recovery technology for internal combustion engines has received widespread attention and research. The most commonly used engine waste heat recovery methods include exhaust gas turbocharging, thermoelectric conversion, and thermodynamic cycle.

[0005] Exhaust gas turbocharging has been widely used in internal combustion engines, but this technology can only utilize a portion of the energy from engine exhaust; the exhaust temperature at the turbine outlet remains relatively high, making it unsuitable for reuse. Waste heat recovery through thermoelectric conversion is primarily limited by the development and application of thermoelectric materials. Currently, these materials are expensive, and their thermoelectric conversion efficiency is relatively low, making them uneconomical for use in engine waste heat recovery systems. Organic Rankine cycle waste heat recovery is the most researched thermodynamic cycle, with companies like Bosch and BorgWarner offering related products for trucks and passenger vehicles. However, Rankine cycle-based waste heat recovery systems are complex, and their size and weight are difficult to meet the requirements for vehicle-wide applications. While there has been some research on Stirling cycle-based waste heat recovery, developments specifically for hybrid commercial vehicle systems are rare. Utility Model Content

[0006] To address the above technical problems, this utility model provides a Stirling waste heat recovery system for hybrid commercial vehicles that has a simple structure, can effectively recover and utilize the exhaust waste heat of hybrid engines, and improves the overall fuel efficiency of the vehicle.

[0007] The technical solution is as follows: A Stirling waste heat recovery system for hybrid commercial vehicles, the key features of which include a hybrid engine, a Stirling engine, and a generator. An exhaust pipe is provided between the hybrid engine and the Stirling engine. The inlet end of the exhaust pipe is connected to the outlet end of the hybrid engine, and the outlet end of the exhaust pipe is connected to the expansion chamber of the Stirling engine. The end of the Stirling engine away from the expansion chamber is connected to the input end of the generator. The output end of the generator is connected to an electric air pump, which is connected to the exhaust pipe near the hybrid engine via a regulating pipe. With this structure, the exhaust gas generated by the hybrid engine after operation is transferred to the Stirling engine to perform work, thereby driving the connected generator to generate electricity and reusing the exhaust gas. The electric air pump is also provided to regulate the air pressure of the hybrid engine, creating a negative pressure to reduce the engine exhaust back pressure, thereby improving engine combustion efficiency and reducing fuel consumption.

[0008] Preferably, an exhaust gas purification device is also installed on the exhaust pipe, located near one end of the hybrid engine. With this structure, the exhaust gas purification device can perform preliminary purification of the exhaust gas generated by the hybrid engine before it is fed into the Stirling engine, reducing damage to the Stirling engine from the exhaust gas and extending its service life.

[0009] Preferably, the Stirling engine includes an expansion chamber and an expansion piston disposed within the expansion chamber. A compression chamber is also disposed near the expansion piston, and a compression piston is disposed within the compression chamber. With this structure, the exhaust gas from the hybrid power engine can enter the expansion chamber of the Stirling engine. The working fluid in the expansion chamber expands upon heating, pushing the expansion piston and causing the compression piston to perform work.

[0010] Preferably, the Stirling engine further includes a regenerative pipe and a regenerator mounted on the regenerative pipe. One end of the regenerative pipe communicates with the expansion chamber located away from the expansion piston, and the other end communicates with the compression chamber located near the expansion piston. With this structure, the working fluid is recovered and reused through the regenerator and regenerative pipe, reducing losses.

[0011] Preferably, the generator input terminal is connected to the compression piston;

[0012] The generator's output terminals are connected to a drive motor, a power battery, and an electric air pump. With this structure, the compression piston drives the generator to produce electricity, which is then consumed and used through three different pathways (drive motor, power battery, and electric air pump), thus achieving full utilization.

[0013] Preferably, the power battery and the electric air pump are electrically connected. With this structure, the electricity stored in the power battery can not only power the vehicle's next operation or meet the needs of the vehicle's electrical equipment, but also provide energy for the electric air pump.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: by adding a simple hardware structure, the waste heat recovery of the hybrid system of the hybrid commercial vehicle is realized. Compared with other commercial vehicles with waste heat recovery systems, the system has a simpler structure, is easier to arrange and control in the whole vehicle, and has higher thermoelectric conversion efficiency. Compared with other commercial vehicles without waste heat recovery systems, the system effectively recovers and utilizes the exhaust waste heat of the hybrid engine, thereby improving the fuel efficiency of the whole vehicle. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a schematic diagram of hybrid power engine 1;

[0017] Figure 3 This is a schematic diagram of the Stirling engine 2. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0019] like Figures 1 to 3As shown, a Stirling waste heat recovery system for a hybrid commercial vehicle includes a hybrid engine 1, a Stirling engine 2, and a generator 3. An exhaust pipe 13 is provided between the hybrid engine 1 and the Stirling engine 2. The inlet end of the exhaust pipe 13 is connected to the outlet end of the hybrid engine 1, and the outlet end of the exhaust pipe 13 is connected to the expansion chamber 21 of the Stirling engine 2. The end of the Stirling engine 2 away from the expansion chamber 21 is connected to the input end of the generator 3. An electric air pump 6 is connected to the output end of the generator 3. The electric air pump 6 is connected to the exhaust pipe 13 near the hybrid engine 1 through an adjusting pipe 7, which can reduce the exhaust back pressure of the hybrid engine and achieve effective combustion of the hybrid engine.

[0020] An exhaust gas purification device 12 is also provided on the exhaust pipe 13. The exhaust gas purification device 12 is close to one end of the hybrid engine 1 and can perform preliminary purification treatment on the exhaust gas discharged by the hybrid engine 1, reduce the wear and tear on the Stirling engine 2, and shorten the service life of the Stirling engine 2.

[0021] The Stirling engine 2 includes an expansion chamber 21 and an expansion piston 22 disposed in the expansion chamber 21. A compression chamber 25 is also disposed on the side near the expansion piston 22, and a compression piston 23 is disposed in the compression chamber 25.

[0022] The Stirling engine 2 also includes a regenerative pipe and a regenerator 24 disposed on the regenerative pipe. One end of the regenerative pipe is connected to the expansion chamber 21 at the end away from the expansion piston 22, and the other end is connected to the compression chamber 25 at the end close to the expansion piston 22.

[0023] The input end of the generator 3 is connected to the compression piston 23; the output end of the generator 3 is connected to the drive motor 4, the power battery 5, and the electric air pump 6. The power battery 5 and the electric air pump 6 are electrically connected.

[0024] The operating principle is as follows: After the exhaust gas and waste heat from combustion in the cylinder 11 of the hybrid engine 1 are initially purified by the exhaust gas purification device 12, they are sent into the expansion chamber 21 of the Stirling engine 2 through the exhaust pipe 13 to heat the working fluid in the expansion chamber 21. The working fluid expands due to the heat and pushes the expansion piston 22 to move, thereby causing the compression piston 23 to do work. The compression piston 23 is connected to the generator 3 and can drive the generator 3 to generate electricity. The electricity generated by the generator 3 can be used in three ways according to the operating needs of the vehicle: first, it can be used directly as the energy source of the drive motor 4 to drive the vehicle; second, this part of the electrical energy can be stored in the power battery 5 for the next use of the vehicle; third, it can be used to directly drive the electric air pump 6 at the exhaust end of the hybrid engine 1 to reduce the exhaust back pressure of the hybrid engine 1 and achieve effective combustion of the hybrid engine.

[0025] The specific situation of the first approach is as follows: when the SOC value (state of charge, i.e., charge) of the power battery 5 is ≥80%, and the vehicle is in a high-power operation (high-speed cruising, climbing, etc.) condition, the electricity generated by the generator 3 is directly used as the driving energy of the drive motor 4 through the power connection. It and the electrical energy provided by the power battery 5 drive the drive motor 4 to do work, providing the high power required for the operation of the vehicle.

[0026] The second approach is as follows: when the SOC value of the power battery 5 is less than 80%, and the vehicle is operating under medium to low load conditions, the electricity generated by the generator 3 is stored in the power battery 5 through the power connection to supply the next operation of the vehicle or the needs of the vehicle's electrical equipment.

[0027] The third approach works as follows: When the vehicle is operating at high power, the hybrid engine 1 is also typically operating at high power with a large exhaust flow. The exhaust back pressure increases exponentially with the increase in exhaust flow. Simultaneously, the addition of the Stirling engine 2 further exacerbates the exhaust back pressure of the hybrid engine 1. Increased exhaust back pressure worsens the in-cylinder combustion of the hybrid engine 1, reducing combustion efficiency. The electric air pump 6, driven by the generator 3, operates at the exhaust end of the hybrid engine, creating negative pressure to reduce the engine's exhaust back pressure, thereby improving engine combustion efficiency and reducing fuel consumption.

[0028] By adding a simple hardware structure, waste heat recovery of the hybrid system in hybrid commercial vehicles is achieved. Compared with other commercial vehicles with waste heat recovery systems, the system has a simpler structure, is easier to arrange and control in the vehicle, and has higher thermoelectric conversion efficiency. Compared with other commercial vehicles without waste heat recovery systems, the system effectively recovers and utilizes the exhaust waste heat of the hybrid engine, improving the overall fuel efficiency of the vehicle.

[0029] Finally, it should be noted that the above description is merely a preferred embodiment of the present utility model. Those skilled in the art, under the guidance of the present utility model, can make various similar representations without departing from the spirit and claims of the present utility model, and such modifications all fall within the protection scope of the present utility model.

Claims

1. A Stirling waste heat recovery system for a hybrid commercial vehicle, characterized by: The device includes a hybrid power engine (1), a Stirling engine (2), and a generator (3). An exhaust pipe (13) is provided between the hybrid power engine (1) and the Stirling engine (2). The inlet end of the exhaust pipe (13) is connected to the outlet end of the hybrid power engine (1), and the outlet end of the exhaust pipe (13) is connected to the expansion chamber (21) of the Stirling engine (2). The end of the Stirling engine (2) away from the expansion chamber (21) is connected to the input end of the generator (3). The output end of the generator (3) is connected to an electric air pump (6). The electric air pump (6) is connected to the exhaust pipe (13) near the hybrid power engine (1) through an adjusting pipe (7).

2. The Stirling waste heat recovery system for hybrid commercial vehicles according to claim 1, characterized in that: An exhaust gas purification device (12) is also provided on the exhaust pipe (13), and the exhaust gas purification device (12) is located near one end of the hybrid engine (1).

3. The Stirling waste heat recovery system for hybrid commercial vehicles according to claim 1, characterized in that: The Stirling engine (2) includes an expansion chamber (21) and an expansion piston (22) disposed in the expansion chamber (21). A compression chamber (25) is also disposed on the side near the expansion piston (22), and a compression piston (23) is disposed in the compression chamber (25).

4. A Stirling waste heat recovery system for hybrid commercial vehicles according to claim 3, characterized in that: The Stirling engine (2) also includes a regenerative pipe and a regenerator (24) disposed on the regenerative pipe. One end of the regenerative pipe is connected to the expansion chamber (21) away from the expansion piston (22), and the other end is connected to the compression chamber (25) near the expansion piston (22).

5. A Stirling waste heat recovery system for hybrid commercial vehicles according to claim 4, characterized in that: The input end of the generator (3) is connected to the compression piston (23); The output terminals of the generator (3) are respectively connected to the drive motor (4), the power battery (5) and the electric air pump (6).

6. A Stirling waste heat recovery system for hybrid commercial vehicles according to claim 5, characterized in that: The power battery (5) and the electric air pump (6) are electrically connected.

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