CN102865166A - Device and method for preparing hydrogen and oxygen by utilizing waste heat of tail gas to perform temperature difference generation - Google Patents

Abstract

The invention relates to a device and a method for preparing hydrogen and oxygen by utilizing waste heat of tail gas to perform temperature difference generation and belongs to the technical field of energy recovery of vehicle. According to the device provided by the invention, a set of temperature difference generation system and a set of hydrogen preparing, storing and supplying system are added on the basis of the maintenance of an internal-combustion engine 1 and an exhaust pipe 7. According to the device provided by the invention, a high-temperature heat source is supplied by smartly utilizing the tail gas of the internal-combustion engine, a low-temperature heat source is supplied by utilizing a radiating fin, and the temperature difference is generated on the two sides of a temperature difference generating device and the electricity is generated and supplied to a hydrogen oxygen preparing machine for preparing the hydrogen and the oxygen, so that the utilization for the waste heat of the tail gas of the internal-combustion engine is realized, the whole running efficiency of the internal-combustion engine is increased, the heating efficiency of the internal-combustion engine is increased and the generation of harmful emission, such as HC and CO, is reduced.

Description

A device and method for producing hydrogen and oxygen by thermoelectric power generation using exhaust waste heat

technical field

The invention provides a device and method for generating hydrogen and oxygen by using the waste heat of the tail gas of an internal combustion engine. The specific content relates to a device and method for generating hydrogen and oxygen by using the waste heat of the tail gas of an internal combustion engine through a thermoelectric power generation device and supplying it to a vehicle-mounted hydrogen and oxygen generator to produce hydrogen and oxygen on board. Device and control method.

Background technique

Improving the thermal efficiency of internal combustion engines has become an important trend in the development of internal combustion engines. In recent years, hydrogen internal combustion engines and hydrogen-doped internal combustion engines have been proven to achieve higher thermal efficiency and lower harmful emissions than traditional gasoline and diesel engines. However, due to the lack of hydrogen infrastructure, both pure hydrogen and hydrogen-doped internal combustion engines have the problem of difficult hydrogenation. The problem of difficult hydrogen refilling can be solved by adding a vehicle-mounted hydrogen and oxygen generator to electrolyze water to produce hydrogen and oxygen, but the hydrogen and oxygen generator still consumes part of the energy when electrolyzing water.

About 30% of the energy in the fuel of an internal combustion engine is directly discharged through the exhaust pipe. Therefore, if the heat energy in the recovered exhaust gas can be used to generate hydrogen, the thermal efficiency of pure hydrogen and hydrogen-doped internal combustion engines can be further improved, and the recovery and utilization of waste heat from engine exhaust can be realized. However, the exhaust gas temperature of the internal combustion engine is usually only about 300 to 400 degrees Celsius, so it belongs to low-grade heat energy, and there is a problem of difficulty in utilization.

The thermoelectric power generation system can use the Seebeck effect to convert thermal energy into electrical energy under the condition that there is a small temperature difference between the two ends of the thermoelectric power generation material. Therefore, the thermoelectric power generation device can convert low-grade thermal energy into high-grade electrical energy.

Contents of the invention

Aiming at the current problems of hydrogen and oxygen filling and on-vehicle storage and transportation, hydrogen and oxygen generator consumes a large amount of battery power, and internal combustion engine exhaust heat is difficult to use, the present invention provides a thermoelectric hydrogen and oxygen production method using the waste heat of internal combustion engine exhaust. devices and methods.

The present invention adopts the following technical scheme. A device for thermoelectrically generating hydrogen and oxygen by using the waste heat of internal combustion engine exhaust in the present invention includes the original internal combustion engine 1 and exhaust pipe 7 of the vehicle. The present invention adds a set of thermoelectric power generation system and a set of hydrogen production, storage and supply system on the basis of retaining the internal combustion engine 1 and the exhaust pipe 7, including: the box body 3 connected to the exhaust pipe of the internal combustion engine through a flange , the thermoelectric generating set 5 installed on the outer surface of the box body 3, the heat sink group 4 installed above the thermoelectric generating set 5, the positive and negative leads of the thermoelectric generating set 5 are connected to the voltage stabilizer 8 respectively, and the voltage stabilizer 8 Negative lead wire is connected with the negative pole of oxyhydrogen generator 9, the positive pole of voltage stabilizer 8 is connected through relay 6, and relay 6 is connected with the positive pole of oxyhydrogen generator 9 by wire, the hydrogen produced by oxyhydrogen generator 9 and oxygen are respectively connected to the hydrogen tank 10 and the oxygen tank 11 through stainless steel pipelines, the hydrogen pressure sensor 13 and the oxygen pressure sensor 12 are respectively installed on the hydrogen tank 10 and the oxygen tank 11, and on the outlets of the hydrogen tank 10 and the oxygen tank 11 A hydrogen tank solenoid valve 15 and an oxygen tank solenoid valve 14 are installed respectively.

The electronic control unit 2 is connected to the voltage stabilizer 8 through wires to obtain a voltage signal f, and the electronic control unit 2 is respectively connected to the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 through wires to obtain the oxygen tank pressure signal a and the hydrogen tank pressure signal c, The electronic control unit 2 is respectively connected with the oxygen tank solenoid valve 14 and the hydrogen tank solenoid valve 15 through wires and controls the oxygen tank solenoid valve 14 and the hydrogen tank solenoid valve by sending the oxygen tank solenoid valve control signal b and the hydrogen tank solenoid valve control signal d 15 is turned on and off, the electronic control unit 2 is also connected to the relay 6 through wires and controls the on-off of the relay 6 by sending the oxygen hydrogen generator relay control signal e to control the start and stop of the hydrogen oxygen generator 9 .

The thermoelectric generating set 5 is made of semiconductor thermoelectric generating material;

The box body 3 is made of a metal material with good thermal conductivity;

The heat sink group 4 is made of metal materials such as copper with good thermal conductivity;

The volume ratio of the hydrogen tank 10 to the oxygen tank 11 is 2:1.

The operating mode of a hydrogen and oxygen production device for thermoelectric power generation by using the waste heat of the exhaust gas of the internal combustion engine is as follows:

A thermoelectric power generation unit 5 in a hydrogen and oxygen plant using the waste heat of the exhaust gas of an internal combustion engine is installed on the outer wall surface of the box body 3, and the box body 3 is connected to the exhaust pipe 7 through a flange, so that the exhaust gas in the box body 3 can be Provide a high-temperature heat source for the thermoelectric generating set 5, and the heat sink group 4 connected with the thermoelectric generating set 5 can dissipate heat for the other end of the thermoelectric generating set 5 and provide a low-temperature heat source for the thermoelectric generating set 5, and the thermoelectric generating set 5 exists in high and low temperature heat sources It can generate electricity under the condition of temperature difference. When the system is running, the electronic control unit detects the voltage signal f sent by the voltage stabilizer 8. When the voltage signal f is stable at 36V±1V, the electronic control unit sends a hydrogen generator relay control signal e Turn on the relay 6 so that the hydrogen and oxygen gas 9 can use the electric energy provided by the thermoelectric power generation unit 5 to electrolyze water to produce hydrogen and oxygen. When the hydrogen and oxygen generator 9 is running, the electronic control unit 2 detects the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 at the same time The oxygen tank pressure signal a and the hydrogen tank pressure signal c sent out, when the oxygen tank pressure signal a and the hydrogen tank pressure signal c indicate that the pressure of any gas tank in the oxygen tank 11 or hydrogen tank 10 is higher than 5bar, the electronic control unit passes Send the hydrogen oxygen generator relay control signal e to disconnect the circuit where the relay 6 is located, so that the hydrogen oxygen generator 9 stops producing gas to ensure system safety. In order to prevent gas backflow during the gas supply process, a certain pressure needs to be maintained in the hydrogen and oxygen tanks. Therefore, when the electronic control unit 2 determines that the pressure of any gas tank in the oxygen tank 11 or the hydrogen tank 10 is lower than 1.5 bar according to the oxygen tank pressure signal a and the hydrogen tank pressure signal c, the electronic control unit 2 sends the oxygen tank electromagnetic valve control signal b or hydrogen tank solenoid valve control signal d to close the oxygen tank solenoid valve 14 or the hydrogen tank solenoid valve 15 to stop the external gas supply of the gas tank whose pressure is lower than 1.5 bar. When the pressure of any gas tank in the oxygen tank 11 and the hydrogen tank 10 is greater than or equal to 1.5 bar, the electronic control unit 2 opens the solenoid valve 14 of the oxygen tank or the solenoid valve 15 of the hydrogen tank by sending control signals b, d, so that the gas with a pressure greater than 1.5 bar The tank can supply air to the outside.

Working process of the present invention: the electronic control unit 2 sends the voltage signal f by the voltage stabilizer 8, when the voltage signal f is stable at 36V ± 1V, the electronic control unit sends the hydrogen oxygen machine relay control signal e to connect the relay 6, so that Hydrogen and oxygen gas 9 can use the electric energy provided by thermoelectric power generation unit 5 to electrolyze water to produce hydrogen and oxygen gas. When the hydrogen and oxygen generator 9 is running, the electronic control unit 2 simultaneously detects the oxygen tank pressure sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13. Signal a and hydrogen tank pressure signal c, when the oxygen tank pressure signal a and the hydrogen tank pressure signal c indicate that the pressure of any gas tank in the oxygen tank 11 or hydrogen tank 10 is higher than 5bar, the electronic control unit will send out the hydrogen generator relay The control signal e disconnects the circuit where the relay 6 is located, so that the hydrogen and oxygen generator 9 stops producing gas to ensure system safety. During the gas supply process, when the electronic control unit 2 determines that the pressure of either the oxygen tank 11 or the hydrogen tank 10 is lower than 1.5 bar according to the oxygen tank pressure signal a and the hydrogen tank pressure signal c, the electronic control unit 2 sends out the oxygen tank electromagnetic The valve control signal b or the hydrogen tank solenoid valve control signal d closes the oxygen tank solenoid valve 14 or the hydrogen tank solenoid valve 15 to stop the external gas supply of the gas tank whose pressure is lower than 1.5 bar. When the pressure of any gas tank in the oxygen tank 11 or the hydrogen tank 10 is greater than or equal to 1.5 bar, the electronic control unit 2 opens the oxygen tank solenoid valve 14 or the hydrogen tank solenoid valve 15 by sending control signals b, d to make the gas with a pressure greater than 1.5 bar The tank can supply air to the outside.

The beneficial effects of the present invention are: aiming at the existing problems of difficulty in hydrogenation of pure hydrogen and hydrogen-doped internal combustion engines and difficulty in utilizing the heat of internal combustion engine exhaust, the exhaust gas of internal combustion engines is skillfully used to provide a high-temperature heat source, and the cooling fins are used to provide a low-temperature heat source, so that the two thermoelectric power generation devices side generates a temperature difference and generates electricity to supply the hydrogen and oxygen production mechanism to extract hydrogen and oxygen, thereby realizing the utilization of the waste heat of the exhaust gas of the internal combustion engine and improving the overall operating efficiency of the internal combustion engine; at the same time, the thermoelectric power generation device does not consume the running time of the internal combustion engine during power generation. The generated power only effectively utilizes the remaining energy that is difficult to utilize when the internal combustion engine is running, so that it will not affect the power of the vehicle; Electric energy electrolyzes water to produce hydrogen and oxygen, and converts electric energy into fuel and combustion aids that can be used for combustion by internal combustion engines, thereby helping to improve the thermal efficiency of internal combustion engines and reduce harmful emissions such as HC and CO.

Description of drawings

Fig. 1 structure and working principle diagram of the present invention

In the figure: 1 internal combustion engine; 2 electronic control unit; 3 box body; 4 heat sink; 5 thermoelectric generating set; 6 relay; 7 exhaust pipe; 8 voltage regulator; ; 12 oxygen pressure sensor; 13 hydrogen pressure sensor; 14 oxygen tank solenoid valve; 15 hydrogen tank solenoid valve;

a oxygen tank pressure signal; b oxygen tank solenoid valve control signal; c hydrogen tank pressure signal; d hydrogen tank solenoid valve control signal; e hydrogen generator relay control signal; f voltage signal

Detailed ways

Present embodiment has carried out following experiment on the 1.8L Elantra car produced by Beijing Hyundai:

Before the experiment, according to the structure shown in Figure 1, a device for thermoelectric power generation and gas production using the waste heat of the exhaust gas of the internal combustion engine was built, and the box 3 was installed on the original exhaust pipe 7 of the internal combustion engine 1 through the flange, so that the exhaust gas could directly enter the box. 3 and provide a high-temperature heat source for the thermoelectric power generation unit 5, install the heat sink group 4 on the thermoelectric power generation unit 5, use the heat sink group 4 to cool down the other end of the thermoelectric power generation group 5 and provide a low-temperature heat source, hydrogen and oxygen generator 9, hydrogen The tank 10, the oxygen tank 11, the electronic control unit 2, the relay 6 and the voltage stabilizer 8 are all arranged in the trunk of the vehicle. Negative lead wire is connected with the negative pole of oxyhydrogen generator 9, the positive pole of voltage stabilizer 8 is connected through relay 6, and relay 6 is connected with the positive pole of oxyhydrogen generator 9 by wire, the hydrogen produced by oxyhydrogen generator 9 and oxygen are respectively connected to the hydrogen tank 10 and the oxygen tank 11 through stainless steel pipelines, and the hydrogen pressure sensor 13 and the oxygen pressure sensor 12 are installed on the hydrogen tank 10 and the oxygen tank 11 respectively, and on the outlets of the hydrogen tank 10 and the oxygen tank 11 A hydrogen tank solenoid valve 15 and an oxygen tank solenoid valve 14 are installed respectively. During the experiment, the vehicle was running on a good level road, the driving speed was controlled around 70km/h, and the gearbox gear was in 5th gear.

(1) Hydrogen and oxygen production experiments by recovering heat from tail gas

In this step of the experiment, in order to test the system’s ability to automatically protect hydrogen by using a thermoelectric power generation device and the system’s automatic protection when the hydrogen and oxygen tanks are overpressured, the solenoid valve 15 of the hydrogen tank and the solenoid valve 14 of the oxygen tank are artificially cut off so that the system does not External supply of hydrogen and oxygen. During the experiment, the electronic control unit 2 detects that the voltage of the voltage stabilizer 8 is 36.5V by the voltage signal f, therefore, the electronic control unit 2 connects the relay 6 by sending the oxygen hydrogen generator relay control signal e, so that the hydrogen oxygen generator 9 Start to electrolyze water to produce hydrogen and oxygen. The hydrogen and oxygen production speeds of the hydrogen and oxygen generator under the experimental conditions are 7L/min and 3.5L/min respectively. When the hydrogen and oxygen generator 9 is running, the electronic control unit 2 monitors in real time The oxygen tank pressure signal a and the hydrogen tank pressure signal c sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13, after the oxygen generator 9 starts to produce hydrogen and oxygen for about 20 minutes, the electronic control unit 2 detects the pressure signal a of the oxygen pressure sensor 12. The signal indicating oxygen tank 11 pressure that sends reaches 5.0bar, and at this moment, the electronic control unit 2 disconnects the relay 6 by sending the relay control signal e of the hydrogen-oxygen generator, so that the hydrogen-oxygen generator 9 stops the electrolysis of water to produce hydrogen and oxygen, with Guarantee the safe operation of the system.

(2) Hydrogen and oxygen storage and supply tests

The experiment first tested the operation effect of the system when the gas reserves in the hydrogen and oxygen tanks were insufficient. The electronic control unit 2 detects that the pressures of the oxygen tank 11 and the hydrogen tank 10 according to the signals a and c sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 are 1.2bar and 1.0bar respectively. Signals b and d cut off the solenoid valve 14 of the oxygen tank and the solenoid valve 13 of the hydrogen tank respectively, so that the system does not supply hydrogen and oxygen to the outside. It is 0bar, indicating that the hydrogen and oxygen solenoid valves are successfully closed.

Afterwards, the operation of the system was tested when the gas reserves in the hydrogen and oxygen tanks were sufficient. The electronic control unit 2 detects that the pressures of the oxygen tank 11 and the hydrogen tank 10 according to the signals a and c sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 are 4.7bar and 4.5bar respectively. Signals b and d respectively open the solenoid valve 14 of the oxygen tank and the solenoid valve 13 of the hydrogen tank, so that the system supplies hydrogen and oxygen to the outside. Under the experimental conditions, the gas pressures at the outlets of the hydrogen solenoid valve and the oxygen solenoid valve are respectively 4.7bar and 4.5bar, indicating that the hydrogen and oxygen solenoid valves are successfully opened.

Third, test the hydrogen supply capacity of the system when the pressure of the hydrogen tank is sufficient and the pressure of the oxygen tank is insufficient. The electronic control unit 2 detects that the pressures of the oxygen tank 11 and the hydrogen tank 10 according to the signals a and c sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 are 0.7 bar and 4.5 bar respectively. Signal b closes the solenoid valve 14 of the oxygen tank and opens the solenoid valve 13 of the hydrogen tank by sending a control signal d, so that the system supplies hydrogen to the outside but not oxygen. The gas pressures are 4.5bar and 0bar respectively, indicating that the hydrogen solenoid valve is opened and the oxygen solenoid valve is closed.

Finally, test the hydrogen supply capacity of the system when the pressure of the hydrogen tank is insufficient and the pressure of the oxygen tank is sufficient. The electronic control unit 2 detects that the pressures of the oxygen tank 11 and the hydrogen tank 10 according to the signals a and c sent by the oxygen pressure sensor 12 and the hydrogen pressure sensor 13 are 4.2 bar and 0.9 bar respectively. Signal b opens the solenoid valve 14 of the oxygen tank and closes the solenoid valve 13 of the hydrogen tank by sending a control signal d, so that the system does not supply hydrogen to the outside but supplies oxygen. The gas pressures are 0 bar and 4.2 bar respectively, indicating that the hydrogen solenoid valve is closed and the oxygen solenoid valve is opened.

The above-mentioned experimental results show that the device for generating hydrogen and oxygen by thermoelectrically using the waste heat of the exhaust gas of the internal combustion engine provided by the present invention can effectively provide electric energy for the oxygen generator by recovering the excess heat energy of the exhaust gas of the internal combustion engine and electrolyze water to produce hydrogen and oxygen . Because the thermoelectric power generation device does not consume the useful work done by the internal combustion engine when it provides electric energy for the hydrogen and oxygen generator, the use of this system will not affect the power of the original machine.

Claims (6)

1. A device for thermoelectrically generating hydrogen and oxygen by using the waste heat of internal combustion engine exhaust, characterized in that a thermoelectric power generation system and a set of hydrogen are added on the basis of retaining the internal combustion engine (1) and exhaust pipe (7) The production, storage and supply system includes: the box body (3) connected to the exhaust pipe of the internal combustion engine through the flange, the thermoelectric power generation unit (5) installed on the outer surface of the box body (3), and the thermoelectric power generation unit (5) installed on the 5) The upper heat sink group (4), the positive and negative wires of the thermoelectric power generation unit (5) are respectively connected to the voltage stabilizer (8), and the negative wire of the voltage stabilizer (8) is connected to the hydrogen-oxygen generator (9) The positive pole of the voltage regulator (8) is connected to the positive pole of the hydrogen oxygen generator (9) through the relay (6), and the hydrogen oxygen generator (9) is connected to the oxygen generator through the hydrogen delivery pipeline and the oxygen delivery pipeline respectively. The hydrogen tank (10) is connected to the oxygen tank (11), the hydrogen pressure sensor (13) and the oxygen pressure sensor (12) are installed on the hydrogen tank (10) and the oxygen tank (11) respectively, and the hydrogen tank (10) and the oxygen tank A hydrogen tank solenoid valve (15) and an oxygen tank solenoid valve (14) are respectively installed on the outlet of the tank (11); The electronic control unit (2) is connected with the voltage regulator (8) to obtain the voltage signal f, and the electronic control unit (2) is respectively connected with the oxygen pressure sensor (12) and the hydrogen pressure sensor (13) to obtain the oxygen tank pressure signal a and The hydrogen tank pressure signal c, the electronic control unit (2) is connected with the oxygen tank solenoid valve (14) and the hydrogen tank solenoid valve (15) respectively, and is controlled by sending the oxygen tank solenoid valve control signal b and the hydrogen tank solenoid valve control signal d To open and close the oxygen tank electromagnetic valve (14) and the hydrogen tank electromagnetic valve (15), the electronic control unit (2) is connected to the relay (6) and controls the relay (6) by sending the relay control signal e of the hydrogen oxygen generator On-off so as to control the start-stop of the hydrogen-oxygen generator (9). 2. A device for producing hydrogen and oxygen by thermoelectric power generation by using exhaust heat of an internal combustion engine according to claim 1, characterized in that: said thermoelectric power generation unit (5) is made of semiconductor thermoelectric power generation materials. 3. A device for thermoelectrically generating hydrogen and oxygen by using exhaust heat of an internal combustion engine according to claim 1, characterized in that the box (3) is made of a metal material with good thermal conductivity. 4. A device for thermoelectrically generating hydrogen and oxygen by using exhaust heat of an internal combustion engine according to claim 1, characterized in that the heat sink group (4) is made of metal materials such as copper with good thermal conductivity. 5. A device for thermoelectrically generating hydrogen and oxygen by using waste heat of internal combustion engine exhaust according to claim 1, characterized in that the volume ratio of the hydrogen tank (10) to the oxygen tank (11) is 2:1. 6. A kind of device that utilizes the waste heat of internal combustion engine tail gas to carry out thermoelectric power generation hydrogen, oxygen described in claim 1, it is characterized in that, this control method is specifically as follows: When the device is running, the electronic control unit (2) detects the voltage signal f sent by the voltage regulator (8), and when the voltage signal f is stable at 36V±1V, the electronic control unit (2) sends a hydrogen generator relay control signal e Turn on the relay (6) to make the hydrogen and oxygen generator (9) start to work, and use the electric energy provided by the thermoelectric power generation unit (5) to electrolyze water to produce hydrogen and oxygen. When the hydrogen and oxygen generator (9) is running, the electronic control unit (2) Simultaneously detect the oxygen tank pressure signal a and the hydrogen tank pressure signal c sent by the oxygen pressure sensor (12) and the hydrogen pressure sensor (13), when the oxygen tank pressure signal a and the hydrogen tank pressure signal c indicate the oxygen tank (11 ) or the pressure of any gas tank in the hydrogen tank (10) is higher than 5bar, the electronic control unit will cut off the circuit where the relay (6) is located by sending the relay control signal e of the hydrogen generator (9), so that the hydrogen generator (9) stops producing Take hydrogen and oxygen to ensure the safety of the system; when the electronic control unit (2) determines that the pressure of either the oxygen tank (11) or the hydrogen tank (10) is lower than 1.5 bar according to the pressure signal a of the oxygen tank and the pressure signal c of the hydrogen tank , the electronic control unit (2) closes the oxygen tank solenoid valve (14) or the hydrogen tank solenoid valve (15) by sending the oxygen tank solenoid valve control signal b or the hydrogen tank solenoid valve control signal d Gas supply; when the pressure of any one of the oxygen tank (11) and hydrogen tank (10) is greater than or equal to 1.5 bar, the electronic control unit (2) opens the oxygen tank solenoid valve (14) or the hydrogen tank by sending control signals b and d The solenoid valve (15) enables the gas tank with a pressure greater than 1.5 bar to supply gas to the outside. the

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