CN115149045A - Fuel cell engine cold start system and method - Google Patents
Fuel cell engine cold start system and method Download PDFInfo
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- CN115149045A CN115149045A CN202211075704.6A CN202211075704A CN115149045A CN 115149045 A CN115149045 A CN 115149045A CN 202211075704 A CN202211075704 A CN 202211075704A CN 115149045 A CN115149045 A CN 115149045A
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Abstract
The invention provides a cold start system and a cold start method of a fuel cell engine.A gas inlet module, a mass flow meter, an air compressor, a bypass valve and a galvanic pile packaging box body are sequentially connected to form a heating loop of the galvanic pile packaging box body; the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are sequentially connected to form a water circulation heating loop; the air inlet module, the mass flowmeter, the air compressor, the throttle valve, the intercooler, the inner cathode runner of the electric pile and the backpressure valve are sequentially connected to form a heating loop of the cathode runner of the electric pile. The system can heat the fuel cell stack by adopting three modes, specifically, the system comprises cooling liquid heating, stack cathode runner heating and stack packaging box heating, and can realize the quick start of a fuel cell engine.
Description
Technical Field
The invention relates to the technical field of fuel cells, in particular to a cold start system and a cold start method of a fuel cell engine.
Background
When the fuel cell engine is started at the temperature of more than 0 ℃, liquid water and gaseous water generated by the fuel cell engine can be discharged through the system, however, when the fuel cell engine is started at a low temperature below 0 ℃, because the temperature of the electric pile at the initial starting stage is lower, and the system does not generate heat, the water generated by the reaction of the system under a large-current working condition can be quickly frozen, and the freezing rate is far greater than the ice melting rate, so that the proton exchange membrane and the gas diffusion layer can be covered by the ice layer, and the bipolar plate can cause extrusion and even damage, at the moment, the electric pile can not normally work, and the low-temperature starting fails. The related art generally adopts an internal heating method and an external heating method to start the fuel cell engine, but the related art only heats the cooling liquid circulation loop, the heating effect is poor, and the cold start speed of the fuel cell engine is slow.
Disclosure of Invention
The invention aims to provide a cold start system and a cold start method of a fuel cell engine, which are used for improving the heating effect and increasing the cold start speed of the fuel cell engine.
The invention provides a cold start system of a fuel cell engine, which comprises: the system comprises a galvanic pile, a water pump, an intercooler, a thermostat, an air inlet module, a mass flow meter, an air compressor, a throttle valve, a bypass valve and a back pressure valve; the air inlet module, the mass flow meter, the air compressor, the bypass valve and the electric pile packaging box body are sequentially connected to form a heating loop of the electric pile packaging box body; the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are sequentially connected to form a water circulation heating loop; the air inlet module, the mass flow meter, the air compressor, the throttle valve, the intercooler, the pile internal cathode flow channel and the backpressure valve are sequentially connected to form a pile cathode flow channel heating loop.
Further, the system further comprises: a heat radiation fan; the heat radiation fan is respectively connected with the thermostat and the water pump; the heat dissipation fan is used for dissipating heat so as to enable the electric pile to work at a preset temperature.
Further, the system further comprises: a first temperature sensor and a second temperature sensor; the first temperature sensor is used for collecting the temperature of the cooling liquid at the outlet of the galvanic pile; the second temperature sensor is used for collecting the inlet temperature of the electric pile packaging box body.
Further, the system further comprises: a tail gas temperature sensor; the tail row temperature sensor is connected with an air tail row of the electric pile; the tail exhaust temperature sensor is used for collecting the temperature of the air tail exhaust.
The invention provides a cold starting method of a fuel cell engine, which is applied to any one cold starting system of the fuel cell engine, and comprises the following steps: when the ambient temperature is not higher than zero and the temperature of the cooling liquid at the outlet of the electric pile is lower than a preset first threshold value, controlling the fuel cell engine to work in a cold start mode, starting the air compressor, opening the bypass valve, and heating the electric pile packaging box body through the electric pile packaging box body heating loop; when the inlet temperature of the electric pile packaging box body reaches a preset second threshold value, a throttle valve, a back pressure valve and a water pump are opened, a bypass valve is closed, electric pile cooling liquid is heated through a water circulation heating loop, an internal cathode flow channel of the electric pile is heated through an electric pile cathode flow channel heating loop until the temperature of the electric pile outlet cooling liquid reaches a preset third threshold value, and the fuel cell engine is controlled to be switched to a normal operation mode from a cold start mode.
Further, before the step of starting the air compressor, the method further comprises: and confirming that the self-checking of the electric pile, the water pump, the intercooler, the thermostat, the air inlet module, the mass flow meter, the air compressor, the throttle valve, the bypass valve and the back pressure valve is normal after the electrification.
Further, the method comprises: and when the inlet temperature of the pile packaging box body does not reach the preset second threshold value, increasing the rotating speed of the air compressor to increase the heat generating power until the inlet temperature of the pile packaging box body reaches the preset second threshold value.
Further, the air heat dissipation power that the intercooler produced does: p Air =P 1 + Prad + Pcon; wherein, P 1 The circulating heat dissipation power of the cooling liquid of the intercooler is obtained; zxfoom P rad Radiating heat dissipation power for an intercooler; p con The natural convection heat dissipation power of the intercooler shell and the air is achieved.
Further, the determination condition for switching the fuel cell engine from the cold start mode to the normal operation mode includes: t > (Q4 + Q5+ Q6)/(P1 + P2+ P3), and T2> T2'; wherein t is the time from the start of cold start to the time when the fuel cell engine can normally output power; t2 is the temperature of the cooling liquid at the outlet of the galvanic pile; t2' is a preset normal starting temperature; q4 is the heat required by the galvanic pile and all parts in the water circulation heating loop to rise to the normal starting temperature T2'; q5 is heat convectively radiated from the outer surface of the pile; q6 is heat radiated by the galvanic pile; p1 is the heating power corresponding to the water circulation heating loop; p2 is the heating power corresponding to the heating loop of the cathode runner of the galvanic pile; and P3 is the heating power corresponding to the heating loop of the electric pile packaging box body.
Further, after the step of starting the air compressor, the method further comprises: and selecting a maximum thermal efficiency point according to the MAP of the air compressor, and controlling the air compressor to operate according to the rotating speed corresponding to the maximum thermal efficiency point.
The invention provides a cold start system and a cold start method of a fuel cell engine.A gas inlet module, a mass flow meter, an air compressor, a bypass valve and a galvanic pile packaging box body are sequentially connected to form a heating loop of the galvanic pile packaging box body; the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are connected in sequence to form a water circulation heating loop; the air inlet module, the mass flow meter, the air compressor, the throttle valve, the intercooler, the pile internal cathode flow channel and the backpressure valve are sequentially connected to form a pile cathode flow channel heating loop. The system can heat the fuel cell stack by adopting three modes, specifically comprises cooling liquid heating, stack cathode runner heating and stack packaging box heating, and can realize quick start of a fuel cell engine.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of a cold start system of a fuel cell engine according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for cold starting a fuel cell engine according to an embodiment of the present invention;
FIG. 3 is a flow chart of another fuel cell engine cold start method provided by an embodiment of the present invention;
fig. 4 is a flowchart of another cold start method for a fuel cell engine according to an embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the related art, the fuel cell engine is usually started by an internal temperature raising method and an external temperature raising method, wherein the internal temperature raising method mainly includes a method of controlling the output characteristic temperature rise of the stack, an oxygen starvation method, a catalytic method, and the like. The external heating method mainly includes PTC (Positive Temperature Coefficient) heater heating, electromagnetic induction heating, hot gas purging, and the like.
The starting method for the fuel cell engine in the low-temperature environment mainly has the following problems:
(1) Once the calculation of the supply amount of hydrogen is wrong, the control of the output characteristic of the galvanic pile can lead to the burning of the galvanic pile or more serious accidents. Similarly, self-heating methods such as oxygen starvation can adversely affect the life and durability of the stack.
(2) The installation of an external PTC heater assists in temperature rise, increases system cost and complexity, occupies system installation space, reduces system integration level, and increases the electromagnetic interference problem of the system because the PTC is a high-voltage system component.
(3) The heating power of the external PTC heater gradually decreases as the temperature of the coolant increases.
(4) Meanwhile, the existing scheme only heats the cooling liquid circulation loop, and the heating effect is poor.
Based on the above, the embodiments of the present invention provide a cold start system and method for a fuel cell engine, which can be applied to a scenario that requires a cold start of the fuel cell engine.
For the convenience of understanding the present embodiment, a cold start system of a fuel cell engine disclosed in the present embodiment will be described in detail first; as shown in fig. 1, the system includes: the system comprises a galvanic pile, a water pump, an intercooler, a thermostat, an air inlet module, a mass flow meter, an air compressor, a throttle valve, a bypass valve and a back pressure valve.
The air inlet module, the mass flow meter, the air compressor, the bypass valve and the electric pile packaging box body are sequentially connected to form a heating loop of the electric pile packaging box body; the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are sequentially connected to form a water circulation heating loop; the air inlet module, the mass flowmeter, the air compressor, the throttle valve, the intercooler, the inner cathode runner of the electric pile and the backpressure valve are sequentially connected to form a heating loop of the cathode runner of the electric pile.
Fig. 1 shows a fuel cell engine water heat management system and an air system flow, wherein a solid line represents the water heat management system and a dotted line represents the air system. The present embodiment includes at least three modes of stack heating, which are as follows:
heating mode one: the intercooler heats the water circulation loop, and the heating power is P1. When the hydrothermal management system works, the cooling liquid flow path is as follows: the water pump 2 → the electric pile 1 internal cooling liquid flow passage → the thermostat 4 → the intercooler 3 (the intercooler cooling liquid is heated by the convection heat exchange of the air fluid of the air compressor) → the water pump 2, and the intercooler heating loop circulation is completed.
And a second heating mode: the hot air heats the cathode flow channel of the electric pile, and the heating power is P2. When the air system works, the air main path flow route is as follows: atmospheric air → intake module 6 → mass flow meter 7 → air compressor 8 → throttle valve 9 → intercooler 3 → internal flow passage of the cell stack 1 → back pressure valve 11 → atmospheric air; wherein, the normal operating temperature of the intercooler air outlet is about 70 ℃, and the intercooler air outlet can be properly adjusted by combining the first heating mode under the low-temperature environment.
And (3) heating mode three: the hot air heats the electric pile packaging box body, and the heating power is P3. The circulating heating air in the electric pile packaging box body is provided by bypass air, and the air flowing route is as follows: atmosphere → air intake module 6 → mass flow meter 7 → air compressor 8 → bypass valve 10 → inside of the electric pile 1 packaging box → atmosphere.
The fuel cell stack, namely the inside cooling liquid, can be heated in all directions through the three heating modes, and in addition, the three heating modes can be subjected to self-adaptive control according to actual requirements, heated gas at the outlet of the air compressor can be distributed, and the optimal solution of the three heating modes can be realized.
In the cold start system of the fuel cell engine, the air inlet module, the mass flow meter, the air compressor, the bypass valve and the electric pile packaging box body are sequentially connected to form a heating loop of the electric pile packaging box body; the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are sequentially connected to form a water circulation heating loop; the air inlet module, the mass flow meter, the air compressor, the throttle valve, the intercooler, the pile internal cathode flow channel and the backpressure valve are sequentially connected to form a pile cathode flow channel heating loop. The system can heat the fuel cell stack by adopting three modes, specifically comprises cooling liquid heating, stack cathode runner heating and stack packaging box heating, and can realize quick start of a fuel cell engine.
Further, the system further comprises: a heat-dissipating fan; the heat radiation fan is respectively connected with the thermostat and the water pump; the heat dissipation fan is used for dissipating heat so as to enable the electric pile to work at a preset temperature.
The preset temperature can be set according to actual requirements; as shown in fig. 1, in practical implementation, when the cold start is successful, the fuel cell engine is switched to a normal operation mode, and when the required power for system heat dissipation is high, the heat dissipation fan 5 starts to dissipate heat from the system, so as to ensure that the stack operates at a proper temperature.
Further, the system further comprises: a first temperature sensor and a second temperature sensor; the first temperature sensor is used for collecting the temperature of the cooling liquid at the outlet of the galvanic pile; the second temperature sensor is used for collecting the inlet temperature of the electric pile packaging box body.
Specifically, as shown in fig. 1, a first temperature sensor 202 may be disposed at a location of a stack coolant outlet, and the stack outlet coolant temperature may be obtained by the first temperature sensor 202; the second temperature sensor 204 may be disposed at an inlet of the stack packaging box body heating circuit, which is close to the stack packaging box body, and the inlet temperature of the stack packaging box body heating circuit, which is close to the stack packaging box body, may be obtained by the second temperature sensor 204.
Further, the system further comprises: a tail gas temperature sensor; the tail row temperature sensor is connected with an air tail row of the electric pile; the tail exhaust temperature sensor is used for collecting the temperature of the air tail exhaust.
It is specific, can set up tail row temperature sensor at the air tail row, through this tail row temperature sensor detecting system tail row temperature, if it is higher to detect the temperature value, can circulate tail heat extraction air to the system once more, heat the pile or heat other pipelines and parts in the system, the mode that specifically circulates tail heat extraction air to the system once more can set up according to actual demand is nimble, for example, can set up a circulation loop alone, other pipelines and parts etc. in carrying tail heat extraction air to pile or system.
The embodiment of the invention discloses a cold start method of a fuel cell engine, which is applied to any one of the cold start systems of the fuel cell engine, and as shown in figure 2, the method comprises the following steps:
step S202, when the environment temperature is not higher than zero and the temperature of the cooling liquid at the outlet of the electric pile is lower than a preset first threshold value, controlling the fuel cell engine to work in a cold start mode, starting the air compressor, opening the bypass valve, and heating the electric pile packaging box body through the electric pile packaging box body heating loop.
The first threshold is usually a lower temperature value, and may be specifically set according to an actual requirement; in practical implementation, when the fuel cell engine needs to be started, the temperature of the stack outlet coolant can be collected by the first temperature sensor 202, and the current ambient temperature can be obtained; if the current environment temperature is less than or equal to 0 ℃, and the temperature of the cooling liquid at the outlet of the galvanic pile is lower than a first threshold value, namely the galvanic pile is in a low-temperature environment, a cold start starting mode needs to be started; specifically, the air compressor 8 can be started first, the air compressor outlet temperature is low at the moment due to the fact that the air initial temperature is low and the power of the air compressor is low, at the stage, the bypass valve 10 is completely opened to the bypass path, the main air path throttle valve 9 is closed, and air fluid heats the electric pile packaging box body through the bypass valve 10. The bypass path can realize the surge prevention of the air compressor by controlling the opening of the bypass valve 10.
And step S204, when the inlet temperature of the electric pile packaging box body reaches a preset second threshold value, opening a throttle valve, a back pressure valve and a water pump, closing a bypass valve, heating the electric pile cooling liquid through a water circulation heating loop, heating the cathode flow channel in the electric pile through an electric pile cathode flow channel heating loop until the temperature of the electric pile outlet cooling liquid reaches a preset third threshold value, and controlling the fuel cell engine to be switched from a cold starting mode to a normal operation mode.
The temperature value of the second temperature sensor 204 is monitored in real time, when the required temperature value (corresponding to the second threshold value, for example, 20 ℃) is detected, the throttle valve 9 is gradually opened, the backpressure valve is opened, at this time, the cooling fluid in the intercooler is heated, and simultaneously, the water pump 2 starts to operate at a lower rotating speed. Heating mode two and heating mode three are on. After the second heating mode and the third heating mode are started, the rotating speed of the air compressor is gradually increased, and the temperature of the air is gradually increased, so that the heat output from the air compressor is gradually increased, and the low-temperature cold start of the electric pile is realized more quickly.
In the heat of the hot air of the intercooler, a part of the circulating heat dissipation power P of the cooling liquid 1 The coolant is brought into the electric pile under the action of the water pump 2 to heat the coolant of the electric pile, the heat is transferred to the whole electric pile through the bipolar plate, the temperature of the electric pile is gradually increased, when the temperature of the coolant at the outlet of the electric pile reaches the safe starting temperature of the system, namely the third threshold value, the cold start is determined to be successful, and the fuel cell engine can be controlled to work in a normal operation mode.
According to the cold starting method of the fuel cell engine, when the ambient temperature is not higher than zero and the temperature of the cooling liquid at the outlet of the electric pile is lower than a preset first threshold value, the fuel cell engine is controlled to work in a cold starting mode, the air compressor is started, the bypass valve is opened, and the electric pile packaging box body is heated through the electric pile packaging box body heating loop. When the inlet temperature of the electric pile packaging box body reaches a preset second threshold value, a throttle valve, a back pressure valve and a water pump are opened, the bypass valve is closed, the electric pile cooling liquid is heated through a water circulation heating loop, the internal cathode flow channel of the electric pile is heated through an electric pile cathode flow channel heating loop until the temperature of the electric pile outlet cooling liquid reaches a preset third threshold value, and the fuel cell engine is controlled to be switched to a normal operation mode from a cold start mode. The mode can adopt three modes to heat the fuel cell stack, which is embodied as cooling liquid heating, stack cathode runner heating and stack packaging box heating, and can realize the quick start of a fuel cell engine.
The embodiment of the invention discloses another cold start method of a fuel cell engine, which is realized on the basis of the method of the embodiment, and as shown in figure 3, the method comprises the following steps:
step S302, when the ambient temperature is not higher than zero and the temperature of the stack outlet coolant is lower than a preset first threshold, controlling the fuel cell engine to operate in a cold start mode.
And step S304, confirming that the self-checking of the electric pile, the water pump, the intercooler, the thermostat, the air inlet module, the mass flow meter, the air compressor, the throttle valve, the bypass valve and the back pressure valve is normal after the electrification.
After the cold start mode is started, the fuel cell engine gradually carries out the procedures of low-voltage electrification, system self-checking, high-voltage electrification and the like, whether all the components in the system can work normally or not can be confirmed through the system self-checking, whether the communication among the components is normal or not can be confirmed, if the communication is normal, all the components can work normally, and the self-checking is confirmed to be normal.
Step S306, starting the air compressor, selecting a maximum thermal efficiency point according to the MAP of the air compressor, and controlling the air compressor to operate at a rotating speed corresponding to the maximum thermal efficiency point; and opening the bypass valve, and heating the electric pile packaging box body through the electric pile packaging box body heating loop.
The MAP of the air compressor comprises parameters such as the rotating speed, the flow, the pressure, the temperature rise and the like of the air compressor; after the air compressor is started, the rotating speed and the pressure ratio of the air compressor can be regulated and controlled according to the MAP of the air compressor, the air temperature of the air compressor is highest, the air compressor is controlled to operate according to the regulated and controlled rotating speed corresponding to the maximum heat efficiency point, and after the bypass valve 10 is opened, the stack packaging box body can be heated through the formed heating loop of the stack packaging box body.
And S308, when the inlet temperature of the electric pile packaging box body reaches a preset second threshold value, opening a throttle valve, a back pressure valve and a water pump, closing a bypass valve, heating the electric pile cooling liquid through a water circulation heating loop, heating the cathode flow channel in the electric pile through an electric pile cathode flow channel heating loop until the temperature of the electric pile outlet cooling liquid reaches a preset third threshold value, and controlling the fuel cell engine to be switched from a cold start mode to a normal operation mode.
The air heat dissipation power that the intercooler produced does: p Air =P 1 +P rad +P con (ii) a Wherein, P 1 The circulating heat dissipation power of the cooling liquid of the intercooler is obtained; p rad Radiating heat dissipation power for an intercooler; p is con The natural convection heat dissipation power of the intercooler shell and the air is achieved. Namely the air heat dissipation power P generated by the intercooler Air Can be transmitted in three forms, wherein the cooling liquid circulation heat dissipation power P of the intercooler 1 The fuel cell is brought into the galvanic pile under the action of the water pump 2 to heat the cooling liquid of the galvanic pile, and the heat is transferred to the whole galvanic pile through the bipolar plate, so that the temperature of the galvanic pile is gradually increased to reach the safe starting temperature of the system.
The air heat dissipation power P generated by the intercooler Air And the circulating heat dissipation power P of the cooling liquid of the intercooler 1 And the radiation heat dissipation power P of the intercooler rad Intercooler shell and natural air convection heat dissipation power P con The specific calculation methods of (a) are described as follows:
1. air heat dissipation power P generated by intercooler Air ；
P Air =G Air *C p,Air (T Air1 -T Air2 )；
In the formula, G Air The supercharged air flow is in kg/s; c p,Air The specific heat capacity of the pressurized air is expressed in kJ/(kg K); t is a unit of Air1 The temperature of an air inlet of the intercooler is in the unit of DEG C, and the temperature can be raised by more than 100 ℃ relative to the ambient temperature under the action of the air compressor, namely (T) Air1 -T Inlet temperature of air compressor ) When the temperature is higher than 100 ℃, the thermal power contained in the air flow is up to 10kW when the air flow is 0.1kg/s, which is higher than the rated power of the PTC heater used in the prior related technology; t is Air2 The temperature of the air outlet of the intercooler is in the unit of DEG C.
2. Cooler cooling liquid circulation heat dissipation power P 1 ；
In the formula, V EG Is the coolant flow, and the unit is L/min; c p,EG The specific heat capacity of the cooling liquid is expressed in kJ/(kg DEG C); rho EG For cooling liquid-tightDegree, in kg/L; delta T EG For the temperature rise of the cooling liquid at the inlet and the outlet of the intercooler, delta T EG，max =12℃。
3. Radiation heat dissipation power P of intercooler rad ；
In the formula, delta is the blackness of the galvanic pile; sigma b Is Stefin-Boltzmann constant; a. The rad Is the radiation area of the electric pile; t is INT The intercooler temperature; t is 0 Is ambient temperature.
4. Intercooler shell and natural air convection heat dissipation power P con ；
In the formula, h is a natural convection heat transfer coefficient between the surface of the intercooler and air; a. The INT The surface area of the intercooler is the surface area of the intercooler; t is a unit of air Is the temperature of the air in contact with the intercooler surface; t is INT Is the intercooler temperature.
The embodiment also specifically sets the judgment condition from the cold start to the normal start operation of the system, so as to calculate the time required by the cold start at different temperatures. The following were used:
the heat capacity of the parts of the electric pile 1 body, the small circulation cooling liquid and the small circulation loop (namely the water circulation heating loop) is Q, and the heat quantity of the parts which are increased to the normal starting temperature T2' is Q4.
In the formula, Δ T is the difference between the normal starting temperature and the initial galvanic pile outlet coolant temperature.
The determination condition for switching the fuel cell engine from the cold start mode to the normal operation mode, i.e., the determination condition for normally operating the fuel cell engine, must satisfy the following requirements at the same time: t > (Q4 + Q5+ Q6)/(P1 + P2+ P3), and T2> T2'.
Wherein t is the time from the start of cold start to the time when the fuel cell engine can normally output power; t2 is the temperature of the cooling liquid at the outlet of the galvanic pile; t2' is a preset normal starting temperature; q4 is the heat required by the galvanic pile and all parts in the water circulation heating loop to rise to the normal starting temperature T2'; q5 is heat convectively radiated from the outer surface of the pile; q6 is heat radiated by the galvanic pile; p1 is the heating power corresponding to the water circulation heating loop; p2 is the heating power corresponding to the heating loop of the cathode runner of the galvanic pile; and P3 is the heating power corresponding to the heating loop of the electric pile packaging box body.
Step S310, when the inlet temperature of the electric pile packaging box body does not reach the preset second threshold value, the rotating speed of the air compressor is increased to increase the heat generating power until the inlet temperature of the electric pile packaging box body reaches the preset second threshold value.
The temperature value of real-time supervision second temperature sensor 204 when this temperature value is for reaching the temperature value of demand, can increase the air compressor machine rotational speed to increase heat production power, and then promote the inlet temperature of pile encapsulation box.
To further understand the above embodiment, another flow chart of a cold start method of a fuel cell engine is provided as shown in fig. 4, first obtaining a temperature of stack outlet coolant and a current ambient temperature, determining whether the current ambient temperature is less than or equal to 0 ℃, and the temperature 202 of stack outlet coolant is lower than a cold start setting threshold, if so, starting a low temperature cold start operation program, determining whether the system and components are normally self-checked during startup, if so, calculating power required for heating to a system normal operation temperature point at the current temperature according to information in a heating power database required under different temperature conditions, starting a water pump, operating at a set rotation speed, opening a bypass valve 10 to full open, selecting a maximum thermal efficiency point according to air compressor MAP data under different conditions, starting an air compressor, operating at a set low rotation speed, i.e., operating at a rotation speed corresponding to the maximum thermal efficiency, detecting whether the temperature collected by a second temperature sensor 204 is greater than the set temperature, if not, increasing the air compressor rotation speed, increasing the throttle power, if so, opening 9 and a back pressure valve 11, closing 10, using all power of the air compressor for heating a cathode flow channel and a cooling power flow channel, detecting whether the stack outlet temperature 202 is higher than the set temperature, and if so, continuing to start the cathode coolant flow channel, and to determine whether the cathode flow channel 202 is higher than the temperature, if so as the temperature.
It should be noted that the starting timing of the water pump may be re-opened when the throttle valve 9 and the back pressure valve 11 are opened, and may be specifically set according to actual requirements.
The setting of S407-S410 ensures that the temperature of air entering the galvanic pile and the temperature of the preheating intercooler reach set temperatures, and the set temperatures can be set to be 50 ℃. The measures can achieve the following effects:
1. preheating the bipolar plate and other auxiliary components at the periphery of the galvanic pile;
2. the air fluid entering the cathode flow channel of the stack can be ensured to rapidly heat the cavity of the cathode flow channel and melt the existing small ice crystals, and the safety of the proton exchange membrane and the GDL (which refers to the key component of the fuel cell, namely the gas diffusion layer-the material used by the gas diffusion layer-carbon paper/carbon cloth) in the stack is ensured.
3. The selection of the set temperature can quickly raise the thermal power P1 of the cooling liquid flow channel in the intercooler to a required temperature value, so that the rapid temperature rise of the cooling liquid flow channel is realized.
This scheme is through the high temperature dry air of control air compressor machine export to the mode of being no less than three kinds of heating forms heats the fuel cell galvanic pile simultaneously, and the concrete manifestation is coolant liquid heating, cathode cavity heating, galvanic pile shell internal heating, has realized fuel cell's quick start, and this adds three kinds of heating methods and has realized the all-round heating to fuel cell galvanic pile and internal cooling liquid. In addition, the self-adaptive control can be carried out on the three heating modes by monitoring the pile cathode temperature sensor, the water outlet temperature sensor and the pile shell temperature sensor, the distribution of the heating gas at the outlet of the air compressor is carried out, and the optimal solution of the three heating modes is realized.
The scheme does not adopt the operation of the reactor output characteristic self-heating method and the like which can generate adverse influence on the service life and the durability of the galvanic pile, ensures the safe and stable operation of the system, and prolongs the service life of the system. In addition, an external PTC heater and other auxiliary heating devices are not required to be installed, and the system is provided with components such as an air compressor, an intercooler and a valve, so that the system cost and complexity are reduced, the system integration level is improved, and the problems of electrical faults and electromagnetic interference of the system are reduced.
Meanwhile, the scheme can control the rotating speed of the air compressor 8 and the opening of the throttle valve 9 according to the ambient temperature of cold start and the requirement of low-temperature start time, realizes the controllability of heating power, enables the air heat capacity at the outlet of the air compressor 8 to be maximum, shortens the time of low-temperature cold start, and enhances the user experience. Because under the low temperature environment, proton exchange membrane and gas diffusion layer contain certain solid-state ice in the pile, this scheme adopts high-temperature air fluid to the negative pole runner rapid heating, has realized the rapid heating up of negative and positive pole air cavity, proton exchange membrane and gas diffusion layer, and the safe and normal start efficiency of negative and positive pole air cavity, proton exchange membrane and gas diffusion layer has been ensured to the dissolution of accelerated solid-state ice.
In addition, during actual implementation, water cooling heat of the air compressor can be introduced into the system according to actual requirements to heat the galvanic pile, system pipelines and components; air-cooled heat of an air compressor is introduced into the system to heat the galvanic pile, the system pipeline and the components.
In addition, in the operation process of the system, temperature sensors, pressure sensors and other position sensors at the inlet and the outlet of the galvanic pile are strictly monitored to ensure that the galvanic pile and other parts of the system are in a normal working range.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A cold start system for a fuel cell engine, comprising: the system comprises a galvanic pile, a water pump, an intercooler, a thermostat, an air inlet module, a mass flow meter, an air compressor, a throttle valve, a bypass valve and a back pressure valve;
the air inlet module, the mass flow meter, the air compressor, the bypass valve and the electric pile packaging box body are sequentially connected to form a heating loop of the electric pile packaging box body;
the water pump, the cooling liquid flow passage in the galvanic pile, the thermostat, the intercooler and the water pump are sequentially connected to form a water circulation heating loop;
the air inlet module, the mass flowmeter, the air compressor, the throttle valve, the intercooler, the cathode channel inside the galvanic pile and the backpressure valve are sequentially connected to form a galvanic pile cathode channel heating loop.
2. The system of claim 1, further comprising: a heat radiation fan; the heat dissipation fan is respectively connected with the thermostat and the water pump;
the heat dissipation fan is used for dissipating heat so as to enable the electric pile to work at a preset temperature.
3. The system of claim 1, further comprising: a first temperature sensor and a second temperature sensor;
the first temperature sensor is used for collecting the temperature of the cooling liquid at the outlet of the galvanic pile;
the second temperature sensor is used for collecting the inlet temperature of the electric pile packaging box body.
4. The system of claim 1, further comprising: a tail gas temperature sensor; the tail row temperature sensor is connected with an air tail row of the electric pile;
the tail exhaust temperature sensor is used for collecting the temperature of the air tail exhaust.
5. A cold start method of a fuel cell engine, which is applied to the cold start system of a fuel cell engine according to any one of claims 1 to 4, the method comprising:
when the ambient temperature is not higher than zero and the temperature of the cooling liquid at the outlet of the electric pile is lower than a preset first threshold value, controlling the fuel cell engine to work in a cold start mode, starting the air compressor, opening the bypass valve, and heating the electric pile packaging box body through the electric pile packaging box body heating loop;
when the inlet temperature of the galvanic pile packaging box body reaches a preset second threshold value, the throttle valve, the back pressure valve and the water pump are opened, the bypass valve is closed, the galvanic pile cooling liquid is heated through the water circulation heating loop, the cathode flow channel inside the galvanic pile is heated through the galvanic pile cathode flow channel heating loop until the temperature of the galvanic pile outlet cooling liquid reaches a preset third threshold value, and the fuel cell engine is controlled to be switched from the cold starting mode to the normal operation mode.
6. The method of claim 5, wherein prior to the step of activating the air compressor, the method further comprises:
after the electrification is confirmed, the electric pile, the water pump, the intercooler, the thermostat, the air inlet module, the mass flow meter, the air compressor, the throttle valve, the bypass valve and the back pressure valve are normal in self-checking.
7. The method of claim 5, wherein the method comprises:
and when the inlet temperature of the pile packaging box body does not reach the preset second threshold value, increasing the rotating speed of the air compressor to increase heat generating power until the inlet temperature of the pile packaging box body reaches the preset second threshold value.
8. The method of claim 5, wherein the intercooler generates air heat dissipation power of: p is Air =P 1 +Prad+Pcon；
Wherein, the P is 1 The circulating heat dissipation power of the cooling liquid of the intercooler is obtained; the P is rad Radiating heat dissipation power for an intercooler; the P is con The natural convection heat dissipation power of the intercooler shell and air is achieved.
9. The method according to claim 5, wherein the determination condition for the fuel cell engine to switch from the cold start mode to the normal operation mode includes: t > (Q4 + Q5+ Q6)/(P1 + P2+ P3), and T2> T2';
wherein t is the time from the start of cold start to the time when the fuel cell engine can normally output power; the T2 is the temperature of the cooling liquid at the outlet of the galvanic pile; the T2' is a preset normal starting temperature; the Q4 is the heat required by the galvanic pile and each part in the water circulation heating loop to be increased to the normal starting temperature T2'; the Q5 is heat convectively emitted from the outer surface of the galvanic pile; the Q6 is heat radiated by the electric pile; the P1 is the heating power corresponding to the water circulation heating loop; the P2 is the heating power corresponding to the heating loop of the cathode runner of the galvanic pile; and P3 is the heating power corresponding to the heating loop of the galvanic pile packaging box body.
10. The method of claim 5, wherein after the step of activating the air compressor, the method further comprises:
and selecting a maximum thermal efficiency point according to the MAP of the air compressor, and controlling the air compressor to operate according to the rotating speed corresponding to the maximum thermal efficiency point.
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