Patent Publication Number: US-2023159007-A1

Title: High-pressure thermal fluid brake and engine energy recovery system

Description:
TECHNICAL FIELD 
     The invention relates to the technical field of vehicle energy recovery, in particular to a high pressure thermal fluid brake and engine energy recovery system. 
     BACKGROUND TECHNOLOGY 
     Petroleum is non-renewable energy, and they are polluting when used, and they also produce greenhouse gases. In order to reduce the consumption of Petroleum and reduce greenhouse gas emissions, we must increase the total vehicle energy efficiency by controlling vehicle energy waste, and recovering the brake energy. Whether electric cars are “green energy vehicles” in the new era depends on where the electricity comes from. Coal, petroleum, natural gas and nuclear power plants are not clean energy. 
     The automobile industry has encountered a strong push for all-electric, but the energy density of traditional gasoline is 13 times than of the most advanced lithium batteries, which means that the output of the same energy is small and light in weight (The fuel weight of the same energy is 1/50 of the battery). The energy efficiency of the power system is much higher than that of a traditional internal combustion engine, but the overall comparison is still lighter and more practical than traditional gasoline or diesel vehicle. 
     At present, the average energy efficiency of fuel vehicles is 40% to 45% (the energy efficiency of pure electric vehicles is 90%). If the efficiency of the whole vehicle can be improved to 70%, it will achieve an environmental protection effect that even electric vehicles cannot surpass; however, the actual efficiency of various vehicle energy recovery systems is currently less than 50%. Currently, the commonly used vehicle energy recovery systems include high-pressure gas or hydraulic recovery systems, and hybrid recovery power systems, all of which have shortcomings. 
     High pressure gas recovery system: waste of compressor thermal energy, waste of engine thermal energy, low recovery efficiency. 
     High pressure hydraulic recovery system: need to be equipped with hydraulic system, the use is limited, the recovery efficiency is low. 
     Hybrid/all-electric recovery system: brake recovery is limited by the motor capability, and still needs to use the traditional brake system, especially in high-speed emergency braking. 
     SUMMARY OF THE INVENTION 
     The purpose of the present invention is to provide a high pressure thermal fluid brake and engine energy recovery system for the problems existing in the prior art. 
     For achieving the above object, the technical scheme adopted in the present invention is: 
     The high pressure thermal fluid brake and engine energy recovery system includes one or more interconnected energy collection system and energy storage system, and a control unit connected to the energy collection system and the energy storage system. The control unit is connected with the vehicle controller to at least read and collect acceleration pedal position information, brake pedal position information, vehicle travel parameters and cooling system parameters of the vehicle. The energy collection system recovers vehicle kinetic energy, engine mechanical energy and engine thermal energy and stores the recovered energy in the energy storage system. The control unit controls the energy recovery and release of the energy collection system and the energy storage system according to the vehicle information read and collected. 
     The high pressure thermal fluid brake and engine energy recovery system effectively recovers vehicle braking energy, engine idle energy and engine heat energy by setting energy collection system (ECS) and the energy storage system (ESS) on the vehicle, and controlling the recovery and release of energy through control unit, so as to achieve the purpose of reducing energy waste of motor vehicle system, saving energy, fuel and reducing emissions. At the same time, the recovered energy can provide power for the vehicle through purposeful release, provide air intake boost for the internal combustion engine through supercharge or turbocharger, heating for the vehicle cabin, and charge the battery for hybrid vehicle and all electric vehicle. 
     Specifically, the energy collection system includes an air compressor/engine with a heat exchanger, and the air compressor is respectively provided with solenoid on/off valve, first temperature sensor and first pressure sensor. 
     The air compressor with a heat exchanger is used to recover the kinetic energy of the vehicle and to provide braking for the vehicle. The solenoid on/off valve is used to activate the air compressor. The first temperature sensor and the first pressure sensor are respectively used to monitor the temperature, pressure and other working status of the air compressor. 
     The energy storage system includes a high pressure gas storage tank and a thermal storage tank. The high pressure gas storage tank is connected to the air compressor through a pipe and a few check valves and controllable regulators. The thermal storage tank is connected to the air compressor heat exchanger through a circulating pipeline and a pump. The second temperature sensor and the second pressure sensor are installed on the high pressure gas storage tank, and the third temperature sensor, the third pressure sensor, and a liquid level sensor are installed on the thermal storage tank. 
     The high pressure gas storage tank is used for storing the compressed high pressure gas, and when the system is reversed, the working pressure of the air compressor is controlled by the controllable regulator; the thermal storage tank is used for storing the hydrothermal liquid, and the circulation pump is capable of circulating the hydrothermal liquid and heat exchange with the air compressor; the second temperature sensor and the second pressure sensor respectively monitor the working temperature and pressure of the high pressure gas storage tank. The third temperature sensor, the third pressure sensor and the liquid level sensor monitor the working temperature, pressure and liquid level of the thermal storage tank, respectively. 
     The air compressor is also connected with an solenoid three-way valve, and the engine or battery radiator is also connected through the solenoid three-way valve; the connection between the engine or battery radiator and the energy collection system is controlled by the solenoid three-way valve, the hydrothermal fluid is introduced to absorb the engine heat energy when the vehicle engine needs heat dissipation, and the path is closed when the engine does not need heat dissipation. 
     The solenoid on/off valve, the first temperature sensor, the first pressure sensor, the controllable regulator, the second temperature sensor, the second pressure sensor, the third temperature sensor, the third pressure sensor, the liquid level sensor, and the solenoid three-way valve is connected and or controlled by the control unit. 
     The control unit will also be connected with the vehicle controller to read the acceleration pedal position information, brake pedal position information, vehicle driving speed, engine temperature, coolant temperature and other information. In conjunction of liquid level information, temperature sensor information and pressure sensor information the control unit adjusts the pressure of the regulators, opens and closes of the circulation pump, and switches the flow direction of the solenoid three-way valve. 
     A specific process is: When the control unit reads the vehicle travel parameters and cooling system parameters from the vehicle central controller, and when the brake pedal is activated, the solenoid on/off valve is closed, the air compressor is activated, and the pedal position information is read; the pressure setting of the controllable regulator is adjusted according to calculation (controller calculation), and through the different pressures to be overcome by the air compressor, different braking forces are provided for the vehicle and vehicle kinetic energy is collected. When the throttle pedal is activated, the system reverses and adjusts the pressure setting of the controllable regulator according to the pedal position information, and the air compressor also reverses operation to provide pressure to the air engine to provide power to propel the vehicle. In the process of energy collection, the heat generated by the air compressor will be absorbed by the hydrothermal liquid driven by the liquid pump and stored in the thermal storage tank; in the reverse process, the hydrothermal liquid is returned to the air compressor by the pump to release heat energy, providing energy (thermal energy) to boost the high-pressure gas in the air engine. 
     Further, the air compressor is also provided with a bypass, and the solenoid on/off valve controls the opening and closing of the air inlet and/or the bypass of the air compressor. The air compressor can be bypassed when it is not required to work. 
     Further, an exhaust pipe is arranged on the high pressure gas storage tank, and an overpressure safety protection valve is arranged on the exhaust pipe. When the pressure of the high pressure gas storage tank exceeds the set pressure value of the safety protection valve, the overpressure safety protection valve automatically opens, and after the gas with excessive pressure is discharged through the exhaust pipe, the overpressure safety protection valve will be automatically closed to ensure the safety of the high pressure gas storage tank. 
     Further, the air compressor is connected with an air filter. The air filter filters impurities and dust for the air compressor to ensure the normal operation of the air compressor. 
     Further, the heat exchanger of the air compressor connects the coolant outlet of the engine (the heat source of the engine cooling system) and the radiator inlet from the engine (the inlet of the engine cooling system) respectively through the solenoid three-way valve. The solenoid three-way valve was controlled to recover the engine heat energy according to the need. 
     Further, when recovering the kinetic energy of the vehicle, the energy collection system is connected to the wheel, transmission shaft or transmission of the vehicle; the energy storage system is installed on the vehicle and linked with the energy collection system; the heat of the compressed high pressure gas is extracted from the gas and the air compressor, and the separated heat energy is stored in the thermal storage tank, and the high pressure air of the separated heat energy is stored in the high pressure gas storage tank. When the brake pedal is pressed, the control system controls the braking force by collecting vehicle travel data to adjust the pressure of the regulator connected to the air compressor. 
     When the mechanical energy of the engine is recovered, the energy collection system is directly connected to the engine of the vehicle through a belt or two-stage clutch; and the air compressor is activated when the vehicle is idle and the energy is recovered and stored in the energy storage system. 
     When the engine heat energy is recovered, the energy collection system and energy storage system are directly connected to the engine hot end of the vehicle cooling system; the engine heat energy is absorbed through the heat exchanger and stored in the thermal storage tank. 
     Further, at least one energy recovery method is as follows: the energy collection system separates the heat of the compressed high pressure gas from the air compressor. The compressed air is stored in the high pressure gas storage tank in the energy storage system, and the extracted heat is stored in the thermal storage tank in the energy storage system. The acceleration pedal position information, brake pedal position information, vehicle travel parameters and cooling system parameters of the vehicle are fed back to the control unit, and the control unit will adjusts the pressure setting of the controllable regulator on the air compressor, the pump connected to the thermal storage tank according to the need of energy recovery or propulsion. 
     Further, the energy collection system is connected to each of the vehicle axles; multiple energy collection systems are connected to one energy storage system. 
     Further, the utilization mode of the energy stored through the energy collection system and energy storage system includes at least the following ways: when providing heating to the cabin by connecting the thermal storage system to the cabin heat exchanger; providing high pressure air to air suspension and air brakes by connecting the high pressure gas storage tank to vehicle air tanks through a regulator; providing high pressure air to supercharger or turbocharger by connecting the high pressure gas storage tank to engine air intake through a regulator; providing charging power to electric vehicle battery by connecting high pressure gas storage tank and thermal storage system to a generator through an air motor. 
     The high pressure thermal fluid brake and engine energy recovery system has high energy recovery efficiency with minimum energy loss. When propulsion is needed, the reversed system has the same high efficiency. This system can even substitute the current brake system (friction brake). With the ability to recover engine mechanical energy and waste heat energy, this system can increase the vehicle&#39;s total energy efficiency by 25%˜30%. Considering the normal vehicle energy efficiency is between 40˜45%, implementing this system will cut down fuel consumption and emission greatly. 
     Compared with the prior art, the beneficial effects of the invention are as follows: 1. The high pressure thermal fluid brake and engine energy recovery system effectively recovers vehicle braking energy, engine idle energy and engine heat energy by installing energy collection system (ECS) and the energy storage system (ESS) on the vehicle, and controlling the recovery and release of energy through control unit, so as to achieve the purpose of reducing energy waste of motor vehicle system, saving energy, fuel and reducing emissions; 2. The recovered energy can provide propulsion to the vehicle, provide air intake boost for the internal combustion engine through supercharge or turbocharger, provide heat to the vehicle cabin, provide propulsion to trailer with better handling, and charge the hybrid vehicle and all electric vehicle battery; 3. This system can directly replace the current brake system (brake pad friction braking); and 4. After using this system, the energy efficiency can be improved by 25% to 30%. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system; 
         FIG.  2    is the other schematic diagram of the high pressure thermal fluid brake and engine energy recovery system; 
         FIG.  3    is a schematic diagram of the relationship between pressure and volume change; 
         FIG.  4    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system connected with transmission; 
         FIG.  5    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system connected with axle; 
         FIG.  6    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system connected with axle, wheel; 
         FIG.  7    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system applied to a trailer; 
         FIG.  8    is the schematic diagram of the high pressure thermal fluid brake and engine energy recovery system charging vehicle battery; 
         FIG.  9    is a schematic diagram of the high pressure thermal fluid brake and engine energy recovery system supplying boosting air to engine; 
     
    
    
     Wherein:  1 , energy collection system (ECS);  2 , energy storage system (ESS);  3 , air compressor;  301 , heat exchanger;  4 , solenoid on/off valve;  5 , exhaust pipe;  6 , first temperature sensor;  7 , first pressure sensor;  8 , high pressure gas storage tank;  9 , first controllable regulator;  9   a , second controllable regulator;  10 , overpressure safety protection valve;  11 , exhaust pipe;  12 , second temperature sensor;  13 , second pressure sensor;  14 , thermal storage tank;  15 , pump;  16 , third temperature sensor;  17 , third pressure sensor;  18 , liquid level sensor;  19 , control unit;  20 , air filter;  21 . solenoid three-way valve;  22 , radiator inlet pipe;  23 , coolant outlet;  24 , wheel;  25 , generator;  26 , battery. 
     MODE OF CARRYING OUT THE INVENTION 
     The technical scheme of the invention will be clearly and completely described below in combination with the drawings of the invention. It is clear that the described embodiments are only some of the embodiments of the present invention but not all of them. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in the field without creative working conditions fall within the scope of the protection of the invention. 
     In the description of the present invention, it should be noted that the azimuth or position relations indicated by the terms “middle”, “upper”, “lower”, “inner” and “outer” are based on the azimuth or position relationship shown in the attached drawings, it is only for the purpose of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation and be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to the present invention. In addition, the terms “first” and “second” are used only for descriptive purposes and cannot be understood to indicate or imply relative importance. 
     Embodiment 1 
     As shown in  FIG.  1   , a high pressure thermal fluid brake and engine energy recovery system includes interconnected energy collection systems  1  and energy storage system  2 , and a control unit  19  connected to the energy collection system  1  and the energy storage system  2 . The control unit  19  is connected to a vehicle controller and at least reads and collects acceleration pedal position information, brake pedal position information, vehicle travel parameters and cooling system parameters of the vehicle. The energy collection system  1  recovers vehicle kinetic energy, engine mechanical energy and engine thermal energy and stores the recovered energy in the energy storage system  2 , and the control unit  19  controls the energy recovery and release of the energy collection system  1  and the energy storage system  2  according to the vehicle information read and collected. 
     The high pressure thermal fluid brake and engine energy recovery system effectively recovers vehicle braking energy, engine idle energy and engine heat energy by setting energy collection system (ECS) and the energy storage system (ESS) on the vehicle, and controlling the recovery and release of energy through control unit, so as to achieve the purpose of reducing energy waste of motor vehicle system, saving energy, lowering fuel consumption and reducing emissions. At the same time, the recovered energy can provide power to the vehicle through purposeful release, provide air intake boost for the internal combustion engine through supercharge or turbocharger, heat the vehicle cabin, and charge the hybrid vehicle and all electric vehicle battery. 
     Specifically, the energy collection system  1  includes an air compressor  3  with a heat exchanger  301 , and the air compressor  3  is respectively provided with solenoid on/off valve  4 , first temperature sensor  6  and first pressure sensor  7 . 
     The air compressor  3  with a heat exchanger is used to recover the kinetic energy of the vehicle and to provide braking for the vehicle, the solenoid valve  4  is used to activate the air compressor  3 , and the first temperature sensor  6  and the first pressure sensor  7  are respectively used to monitor the temperature, pressure and other working conditions of the air compressor  3 . 
     The energy storage system  2  comprises a high pressure gas storage tank  8  and a thermal storage tank  14 . The high pressure gas storage tank  8  is connected with the air compressor  3  through a pipe and is provided with a first controllable regulator  9  and a second controllable regulator  9   a  in the opposite control direction. The thermal storage tank  14  is connected with the heat exchanger  301  of the air compressor  3  through a circulation pipe and is provided with a pump  15  on the circulation pipe. The high pressure gas storage tank  8  is respectively provided with second temperature sensor  12  and second pressure sensor  13 , and the thermal storage tank  14  is provided with third temperature sensor  16 , third pressure sensor  17  and liquid level sensor  18 . 
     Wherein, when the air compressor  3  supplies gas to the high pressure gas storage tank  8 , the first controllable regulator  9  is used (i.e., the system is turning forward, at this time the second controllable regulator  9   a  is closed); when the high pressure gas storage tank  8  delivers gas to the air compressor  3  or to the vehicle, the second controllable regulator  9   a  is used (i.e., the system is reversed, and the first controllable regulator  9  is closed). 
     The high pressure gas storage tank  8  is used for storing the compressed high pressure gas, and when the system is reversed, the working pressure of the air compressor  3  is controlled by a second controllable regulator  9   a ; the thermal storage tank  14  is used for storing the thermal energy absorbing liquid (hydrothermal liquid), and the pump  15  is capable of circulating the thermal energy absorbing liquid to exchange heat with the air compressor  3 . The second temperature sensor  12  and the second pressure sensor  13  monitor the working temperature and pressure of the high pressure gas storage tank  8  respectively; the third temperature sensor  16 , the third pressure sensor  17  and the liquid level sensor  18  monitor the working temperature, pressure and liquid level of the thermal storage tank  14 , respectively. 
     The solenoid on/off valve  4 , the first temperature sensor  6 , the first pressure sensor  7 , the first controllable regulator  9 , the second controllable regulator  9   a , the second temperature sensor  12 , the second pressure sensor  13 , the third temperature sensor  16 , the third pressure sensor  17  and the liquid level sensor  18  are respectively connected with the control unit  19 . 
     The control unit  19  is also connected with a vehicle controller to read the acceleration pedal position information, brake pedal position information, vehicle driving speed, engine temperature, coolant temperature and other information, and combine these temperature sensors, pressure sensors and real-time data such as temperature and pressure feedback from liquid level sensor to adjust the pressure setting of the first/second controllable regulator and control the opening and closing of the pump  15 . The control unit  19  is an electronic control unit or chip. 
     One specific control process is that when the control unit  19  reads the vehicle travel parameters and cooling system parameters from the vehicle controller, and when the brake pedal is activated, close the solenoid valve  4 , activate the air compressor  3 , and read the pedal position information. According to the calculation (chip calculation), the pressure setting of the first controllable regulator  9  is adjusted to provide different braking forces for the vehicle and collect the kinetic energy of the vehicle through the different pressures to be overcome by the air compressor  3 . When the throttle pedal is activated, the system reverses and adjusts the pressure setting of the second controllable regulator  9   a  according to the pedal position information, and the air compressor  3  also reverses the operation to provide pressure to the air engine to provide propulsion for the vehicle; in the process of energy collection, the heat generated by the air compressor  3  is absorbed by the hydrothermal fluid driven by the pump  15  and stored in the thermal storage tank  14 . In the reverse process, the hydrothermal fluid is returned to the air compressor  3  by the pump  15  to release heat energy to provide energy to the compressed air which runs the air engine. 
     Further, the air compressor  3  is also provided with an exhaust pipe  5 , and the solenoid on/off valve  4  controls the opening and closing of the air inlet and/or the exhaust pipe  5  of the air compressor. The exhaust tube  5  can be bypassed for the air compressor  3  when it is not required to work. 
     Further, the high pressure gas storage tank  8  is provided with an exhaust pipe  11 , and the exhaust pipe  11  is provided with an overpressure safety protection valve  10 . When the pressure of the high pressure gas storage tank  8  exceeds the set value of the overpressure safety protection valve  10  installed on it, the overpressure safety protection valve  10  is automatically opened, the gas with excessive pressure is discharged through the exhaust pipe  11 , ensuring safety, and automatically shuts off after the gas with excessive pressure is discharged. 
     Further, an air filter  20  is connected to the air compressor  3 . The air filter  20  filters impurities and dust for the air compressor  3  to ensure the normal operation of the air compressor. 
     The present embodiment applies the high pressure thermal fluid brake and engine energy recovery system to gasoline or diesel or gas-electric hybrid vehicles, and the whole system is composed of energy collection system (ECS) and energy storage system (ESS). Multiple CES and ESS can be carried according to the structure and load of the vehicle. 
     Further, solenoid three-way valve  21  is connected to the air compressor  3 , and the engine or battery radiator is connected through the solenoid three-way valve  21 ; the connection between the engine or battery radiator and the energy collection system is controlled by the solenoid three-way valve  21 , and the hydrothermal fluid is introduced when the vehicle needs heat, and the heat recovery or hydrothermal reflux is carried out when the heat energy is not needed; the solenoid three-way valve  21  is connected with the control unit  19 . 
     Specifically, the heat exchanger  301  of the air compressor  3  is respectively connected with the coolant outlet  23  of the engine (the heat source of the engine cooling system) and the radiator inlet pipe  22  of the engine (the inlet of the engine cooling system) through the solenoid three-way valve  21 . The solenoid three-way valve  21  is controlled to dissipate heat (recover energy) or provide thermal energy for the engine as needed. 
     Embodiment 2 
     The difference between this embodiment and Embodiment 1 is that the system of embodiment 1 is simplified without setting an solenoid three-way valve. 
     As shown in  FIG.  2   , the heat exchanger  301  in the air compressor  3  of the energy collection system  1  (ECS) is not connected to the heat dissipation system of the vehicle for use by vehicles that do not have thermal energy to recover, such as some all electric vehicles. 
     However, the energy storage system  2  (ESS) is still cyclically connected with the heat exchanger  301  in the air compressor  3  of the energy collection system  1  (ECS), and can recover the heat energy generated by the air compressor itself and the heat energy brought by the high pressure gas, and release the heat energy when the vehicle or the air compressor needs the heat energy. 
     Embodiment 3 
     The present embodiment describes the principle of high pressure thermal fluid brake and engine energy recovery system in embodiment one or two. 
     As shown in  FIG.  3   , according to the first law of thermodynamics and Carnot cycle, adiabatic compression and adiabatic expansion can store or release more energy (PD&lt;PB) when the gas is compressed (isothermal compression: C point to D point or adiabatic compression C point to B point) or expansion (isothermal expansion A point to B point or adiabatic expansion A point to D point). When air compressor works, because a large amount of heat generated by compressed air will damage the compressor parts or reduce the life of the compressor, the radiator is usually connected to the compressor to ensure that the working temperature of the compressor is not too high. As a result, the system that uses compressed air to recover vehicle braking energy is just like the existing friction brake system, energy (thermal energy) is wasted. 
     The system will recover the heat dissipated from air compressor  3  into the thermal storage tank  14  to realize quasi-adiabatic compression, and when using the stored compressed gas to expand and release energy, the stored thermal energy will be injected back into the system to realize quasi-adiabatic expansion. 
     This system can recover the heat energy of vehicle engine, and can inject more heat energy when using compressed gas expansion than that of quasi-adiabatic compression to realize super adiabatic expansion (system release energy&gt;system recovery energy). 
     In the existing technology, the brake energy recovery system is inefficient because the brake mainly depends on the friction brake system (brake pad friction brake disc), and energy recovery is only used as an auxiliary; therefore, the limited brake energy can only be proportionally distributed to the energy recovery system, and then excluding its own energy conversion waste, the energy recovery is very limited. 
     This system can effectively recover the heat energy of the compressor (will not cause the compressor to overheat and fail), and can flexibly adjust the gas compression pressure, so this system can completely replace the existing friction brake system (brake pad friction brake disc) to recover 100% vehicle kinetic energy and will not be wasted. 
     A theoretical embodiment of energy recovery calculation is as follows: 
     If the vehicle with a weight of 1600 KG (m) drives at a speed of 100 KM/H (v). 
     The kinetic energy of the vehicle is: 
     
       
         
           
             KE 
             = 
             
               
                 
                   1 
                   2 
                 
                 ⁢ 
                 
                   mv 
                   2 
                 
               
               = 
               
                 0.6173 
                     
                 MJ 
               
             
           
         
       
     
     Then the work required to compress the air to brake the vehicle is equal to the kinetic energy of the vehicle. 
     According to thermodynamic formula, PV=nRT 
     
       
         
           
             W 
             = 
             
               
                 
                   ∫ 
                   
                     V 
                     ⁢ 
                     1 
                   
                   
                     V 
                     ⁢ 
                     2 
                   
                 
                 
                   
                     P 
                     ⁡ 
                     ( 
                     V 
                     ) 
                   
                   ⁢ 
                   dV 
                 
               
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                       V 
                       ⁢ 
                       1 
                     
                     
                       V 
                       ⁢ 
                       2 
                     
                   
                   
                     
                       nRT 
                       V 
                     
                     ⁢ 
                     dV 
                   
                 
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                   ln 
                   ⁢ 
                   
                     
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     Assuming that the air temperature is 20° C., R=0.287 kJ/(kg·K), V is the compressed volume of the gas, and the compressed air sets the pressure to 20 MP. When the isothermal compression heat is not recovered by the system, it is necessary to compress 1.385 KG air to 20 MP. 
     When all adiabatic compression heat is recovered by the system, only 0.827 KG air is compressed to 20 MP, and the system efficiency is 1.675 times higher than that of the isothermal compression system. 
     Assuming that the actual working efficiency of the adiabatic compression system is only 80%, the isothermal compression system can only recover 47.76% of the vehicle kinetic energy. 
     Further, the comparison of the above energy recovery calculation is the efficiency ratio when there is no engine thermal energy recovery (such as the system in Embodiment 2), and when there is additional engine thermal and mechanical energy recovery (the system in embodiment 1), depending on the energy recovery time, the efficiency of the vehicle kinetic energy recovery system can be compensated (100%, 80%, 20%). If the engine thermal and mechanical energy recovery time is long enough, the system can recover more than 100% of the kinetic energy of the vehicle. 
     Embodiment 4 
     The present embodiment illustrates several energy recovery modes of the high pressure thermal fluid brake and engine energy recovery system in the first or second embodiment. 
     Depending on the vehicle design, the system can be connected to the transmission output or loaded directly on the wheel or axle. As shown in  FIG.  4   ˜ FIG.  6   , the arrangement of the system connected to the transmission, the axle and the axle and the wheel is illustrated respectively. 
     When recovering the kinetic energy of the vehicle, the air is directly used as the medium, and the pressure of the compressed air is controlled to brake the vehicle. When the air is compressed, a large amount of heat will be generated at the same time. The kinetic energy of the vehicle will be converted into compressed air, mechanical energy and thermal energy will be stored and extracted and reused when needed. 
     Specifically, the energy collection system  1  and energy storage system  2  are connected to the drive shaft or transmission of the vehicle; the heat of the compressed high pressure gas is extracted from the gas at the air compressor  3 , and the high pressure air with lowered temperature is stored in the high pressure gas storage tank  8 , and the separated heat energy is stored in the thermal storage tank  14 . When the brake pedal is pressed, the control system controls the braking force by collecting vehicle travel data to adjust the pressure of the first controllable regulator  9  connected to air compressor  3 . 
     When the mechanical energy of the engine is recovered, the energy collection system  1  and the energy storage system  2  are directly connected to the engine of the vehicle through a belt or two-stage clutch, and connected to the air compressor  3  when the vehicle is at idle. 
     When the engine heat energy is recovered, the energy collection system  1  and energy storage system  2  are directly connected to the engine heat source of the vehicle cooling system; the engine heat energy is recovered through the heat exchanger  301  and stored in the thermal storage tank  14 . 
     Embodiment 5 
     The system can be installed on heavy-duty truck trailer axles to recovery brake energy, provide propulsion and better handling, and increase whole vehicle energy efficiency. As shown in  FIG.  7   , the axle of each pair of wheels  24  is respectively provided with the energy collection system  1 , and a plurality of groups of the energy collection system  1  are connected in parallel with the same energy storage system  2 . 
     Embodiment 6 
     This embodiment describes several energy utilization modes of high pressure thermal fluid brake and engine energy recovery system in embodiment one or two. 
     When providing heating for the vehicle, the thermal storage tank  14  of the energy storage system  2  is connected with the heating radiator of the vehicle. 
     When charging the vehicle battery, as shown in  FIG.  8   , the energy storage system  2  is connected to the generator  25  and then connected to the battery  26 . 
     As shown in  FIG.  9   , when boosting the engine turbocharger or supercharger, the high pressure gas storage tank  8  of the energy storage system  2  is equipped with the second controllable regulator  9   a  and connected with the vehicle engine. 
     When supplying air to the heavy-duty truck pneumatic brake and air suspension system, the high pressure gas storage tank  8  of the energy storage system  2  is equipped with the second controllable regulator  9   a  and connected with the vehicle air tanks. 
     The present system can effectively convert the kinetic energy of vehicle braking into thermal energy and mechanical energy to store, recover and reuse, and reversely convert the recovered energy back to vehicle to provide propulsion, heating and charging when needed. After using this system, the energy utilization rate of the vehicle is increased by 25˜30%, reaching more than 70%, so as to achieve the purpose of energy saving, fuel saving and emission reduction. 
     Although embodiments of the invention have been shown and described, for ordinary technical personnel in the art, it is understandable that a variety of changes, modifications, replacements, and variants can be made to these embodiments without departing from the principle and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.