CN115653748A - Methanol and natural gas dual-fuel engine and control method - Google Patents
Methanol and natural gas dual-fuel engine and control method Download PDFInfo
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- CN115653748A CN115653748A CN202211327579.3A CN202211327579A CN115653748A CN 115653748 A CN115653748 A CN 115653748A CN 202211327579 A CN202211327579 A CN 202211327579A CN 115653748 A CN115653748 A CN 115653748A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
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- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Abstract
The invention discloses a methanol and natural gas dual-fuel engine and a control method thereof, wherein the engine comprises a cylinder body, a natural gas storage tank, a methanol fuel tank, an engine air inlet pipe, a common rail pipe, a nozzle and a methanol vaporizer for forming methanol steam, the engine air inlet pipe is connected with the cylinder body, the common rail pipe is communicated with the engine air inlet pipe through the nozzle, the natural gas storage tank is connected with the common rail pipe through an air inlet pipeline, the methanol fuel tank is connected with the methanol vaporizer through a methanol conveying pipeline, and the methanol vaporizer is connected with the common rail pipe through a methanol steam conveying pipeline and a methanol steam buffer. The engine uses methanol fuel as main fuel and natural gas as auxiliary fuel, the natural gas is used as fuel when cold starting at low temperature, after the engine cooling liquid reaches a certain temperature, the liquid methanol utilizes the waste heat of the waste gas, the vaporizer heats the liquid methanol to change the liquid methanol into methanol steam, the methanol fuel enters the cylinder in the form of methanol steam to burn, and the cold starting at low temperature of the engine is easy.
Description
Technical Field
The invention relates to the technical field of dual-fuel engines, in particular to a methanol and natural gas dual-fuel engine and a control method.
Background
The natural gas is used as the fuel of the internal combustion engine, the natural gas is applied to markets in the subdivided fields of taxies and commercial vehicles, and the natural gas vehicle fuel has certain advantages in fuel operation cost compared with gasoline and diesel fuel.
With the global restriction on greenhouse gas emission, an engine taking methanol as a fuel is more and more widely applied, the methanol is used as a clean and efficient fuel, the raw material source for manufacturing the methanol fuel is rich in China, the cost is low, the industrialization foundation is good, the methanol fuel can be widely applied, and China also has been in cicada union with the first country for manufacturing the methanol fuel and the consumer country for many years. Methanol is used as a fuel of an internal combustion engine, and is applied and popularized on passenger vehicles and commercial vehicles at present, but under the existing technical conditions, the low-temperature cold start of the engine is very difficult due to the characteristics of high ignition temperature, large latent heat of vaporization and small saturated vapor pressure of the methanol, so that gasoline is used as an auxiliary fuel for the low-temperature cold start and the heat engine process in the current products on the market. According to the technical scheme of the dual-fuel system, two fuel oil supply systems are required to be adopted, the dual-fuel system comprises two fuel oil pumps and a nozzle, a control system is complex, meanwhile, methanol is injected into a cylinder as liquid fuel, the abrasion of the cylinder sleeve is aggravated due to the fact that the methanol is poorly atomized and easily washes a cylinder sleeve friction pair, engine oil is easily diluted, emission pollutants are increased, and the reliability and durability of an engine are seriously affected.
In order to avoid the inconvenience of adding two fuels to a client application scene, a single methanol fuel is adopted, the biggest obstacle to be faced is to solve the low-temperature cold starting performance, and related patents propose an alcohol-hydrogen combustion technology, namely, a vehicle cracker is adopted to crack methanol into carbon monoxide and hydrogen (such as Chinese patents CN208843725U, CN108915909B and CN 208843726U), the technology utilizes the waste heat of tail gas of an engine, and the methanol is subjected to catalytic cracking reaction under the high-temperature condition by absorbing the heat of the tail gas, so that liquid methanol is cracked into hydrogen and carbon monoxide cracked gas, and then the hydrogen and the carbon monoxide cracked gas enter a cylinder for combustion. However, the methanol catalytic cracking technology has practical engineering problems of insufficient structural strength of a catalyst, large catalyst volume, unstable cracking temperature of the catalyst, low gas production efficiency and the like, and after hydrogen and carbon monoxide are cracked by methanol with unit mass, the molar volume of the two gases is large, so that the air input of an engine is reduced, the inflation coefficient is reduced, and the dynamic performance of the engine is seriously influenced.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the dual-fuel engine taking methanol as the main fuel and natural gas as the auxiliary fuel and the control method thereof, the engine is easy to start at low temperature and the heat efficiency of the engine is effectively improved.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
the utility model provides a methyl alcohol, natural gas dual-fuel engine, includes cylinder body, natural gas holder, methyl alcohol fuel cell, engine intake pipe, the engine intake pipe links to each other with the cylinder body, still includes common rail pipe, nozzle and is used for forming the methyl alcohol vaporizer of methyl alcohol steam, common rail pipe is linked together through nozzle and engine intake pipe, the natural gas holder passes through the air inlet pipeline and links to each other with common rail pipe, and the methyl alcohol fuel cell passes through methyl alcohol conveying pipeline and links to each other with the methyl alcohol vaporizer, and the methyl alcohol vaporizer passes through conveying methyl alcohol steam pipeline and methyl alcohol vapor buffer and links to each other with common rail pipe.
The nozzle is arranged on an air inlet pipe of the engine to form a methanol steam fuel and natural gas fuel shared nozzle structure.
The exhaust port of the cylinder body is connected with an exhaust pipe, and the methanol vaporizer is arranged on the exhaust pipe.
And a heating water jacket for heating and insulating the air inlet pipe is arranged outside the air inlet pipe of the engine.
And a methanol one-way valve for preventing the methanol vaporizer from generating methanol steam countercurrent is arranged on the methanol conveying pipeline under abnormal conditions.
And a pressure reducing valve and a pressure stabilizing valve are sequentially arranged on an air inlet pipeline connected with the natural gas storage tank, and the upper part of the methanol fuel tank is connected with the pressure stabilizing valve through a high-pressure pipeline.
The common rail pipe is of a three-way structure with two inlets and one outlet, the two inlets are respectively connected with the methanol steam buffer and the natural gas pressure stabilizing valve, and the outlet is connected with the nozzle.
The methanol vaporizer is arranged at the rear end of the engine post-treatment three-way catalytic converter, high-temperature exhaust gas flows through the vaporizer in a full flow mode, an electric exhaust gas bypass valve is arranged in the methanol vaporizer, and closed-loop control is conducted on the opening of the bypass valve by detecting methanol steam temperature feedback.
And the heating water jacket is connected with a small circulation of an engine cooling system.
A control method of a methanol and natural gas dual-fuel engine comprises the following steps: methanol fuel is used as main fuel, natural gas fuel is used as auxiliary fuel, a fuel supply mode is carried out by adopting dual fuel, natural gas fuel is adopted in starting and heat engine working conditions, and after the heat engine is finished, methanol steam is used as main fuel to enter a normal working mode.
Compared with the prior art, the invention has the following advantages:
1. the engine uses methanol fuel as main fuel, natural gas as auxiliary fuel, natural gas is used as fuel when cold starting at low temperature, liquid methanol utilizes waste heat of waste gas after the engine cooling liquid reaches a certain temperature, the liquid methanol is heated by a vaporizer to be changed into methanol steam, the methanol fuel enters a cylinder in a methanol steam mode to be combusted, and the cold starting at low temperature of the engine is easy;
2. methanol is injected into the air inlet pipe in a steam state and is mixed with fresh air more uniformly, so that the combustion speed is accelerated, the effective heat efficiency of the engine is improved, and the content of unburned methanol and HC in discharged pollutants is reduced; in addition, the problem of engine oil dilution can be effectively avoided, the abrasion of a cylinder sleeve and other parts is greatly reduced, and the reliability and the durability of the engine are improved;
3. the methanol steam is sprayed by using one set of gas nozzle shared by the methanol steam and the natural gas, so that the methanol steam injection device is simple in structure, convenient to arrange and install and relatively low in cost.
Drawings
The contents of the description and the references in the drawings are briefly described as follows:
FIG. 1 is a schematic diagram of an engine according to the present invention.
In the figure:
1. a natural gas storage tank; 2. a methanol fuel tank; 3. a methanol vapor buffer; 4. a methanol cut-off valve; 5. an exhaust pipe; 6. a cylinder body; 7. an EGR cooler; 8. a turbocharger; 9. a methanol vaporizer; 10. a methanol check valve; 11. an intercooler; 12. an EGR valve; 13. an air inlet pipe; 14. an EGR mixer; 15. a nozzle; 16. a common rail pipe; 17. a natural gas shut-off valve; 18. a pressure maintaining valve; 19. a pressure reducing valve.
Detailed Description
The following description of the embodiments of the present invention will be made in detail with reference to the accompanying drawings.
As shown in fig. 1, the methanol and natural gas dual-fuel engine uses methanol fuel as a main fuel, natural gas as an auxiliary fuel, natural gas is used as a fuel during low-temperature cold start, liquid methanol is heated by a vaporizer by using waste gas waste heat after engine cooling liquid reaches a certain temperature, the liquid methanol is changed into methanol steam, the methanol fuel enters a cylinder in a methanol steam mode for combustion, and the engine is easy to start at low temperature in a cold state.
Methanol is injected into the air inlet pipe in a steam state and is mixed with fresh air more uniformly, so that the combustion speed is accelerated, the effective heat efficiency of the engine is improved, and the content of unburned methanol and HC in discharged pollutants is reduced; in addition, the problem of engine oil dilution can be effectively avoided, the abrasion of a cylinder sleeve and other parts is greatly reduced, and the reliability and the durability of the engine are improved.
The dual-fuel engine comprises a cylinder body 6, a natural gas storage tank 1, a methanol fuel tank 2, an engine air inlet pipe 13, a common rail pipe 16, a nozzle 15 and a methanol vaporizer 9 for forming methanol steam; the engine intake pipe links to each other with the cylinder body, and the common rail pipe is linked together through nozzle and engine intake pipe, and the natural gas holder passes through the air inlet pipeline and links to each other with the common rail pipe, and the methyl alcohol fuel cell passes through methyl alcohol delivery line and links to each other with the methyl alcohol vaporizer, and the methyl alcohol vaporizer links to each other with the common rail pipe through carrying methyl alcohol steam line and methyl alcohol vapor buffer 3.
The nozzle is arranged on an air inlet pipe of the engine to form a methanol steam fuel and natural gas fuel shared nozzle structure; preferably, the common rail pipe is of a three-way structure with two inlets and one outlet, the two inlets are respectively connected with the methanol steam buffer and the natural gas pressure stabilizing valve, and the one outlet is connected with the nozzle. The methanol steam and the natural gas are injected to share a common rail pipe and a nozzle, and the common rail pipe can play a role in stabilizing gas pressure; according to the flow rate of the methanol, if the flow rate of one nozzle is insufficient, a plurality of nozzles can be connected in parallel on the common rail pipe.
An exhaust pipe 5 is connected with an exhaust port of the cylinder body, the methanol vaporizer is arranged on the exhaust pipe, an EGR cooler 7 and a turbocharger 8 are arranged on the exhaust pipe, the EGR cooler is connected with an engine air inlet pipe through an EGR valve 12, and the turbocharger is connected with the engine air inlet pipe through an intercooler 11; furthermore, a methanol vaporizer is arranged at the rear end of a three-way catalyst for post-processing of an engine, high-temperature waste gas flows through the vaporizer completely, an electric waste gas bypass valve is arranged in the methanol vaporizer, the opening of the bypass valve is controlled in a closed loop mode by detecting temperature feedback of methanol steam, so that the heating waste gas quantity is controlled to meet the requirement of stably controlling the temperature of the methanol steam, and after liquid methanol is vaporized by the methanol vaporizer, a certain amount of methanol steam is stored in a methanol buffer tank, so that the requirement of transient large-load acceleration of the engine can be met. The steam temperature after the methanol vaporization is controlled to be about 70 degrees, and the boiling point of the methanol is 64.7 degrees, so that the methanol is ensured to enter a cylinder for combustion in a gaseous state on one hand, the methanol is prevented from condensing liquid methanol to dilute engine oil, and on the other hand, the air inlet temperature of the engine under a small load is heated, the pumping loss is reduced, and the heat efficiency of the engine is improved.
An interlayer heating water jacket for heating and insulating the air inlet pipe is arranged outside the air inlet pipe of the engine; further, the heating water jacket is communicated with a small circulation of an engine cooler system, heat preservation is carried out on the air inlet pipe through engine cooling liquid, and it is guaranteed that methanol steam cannot be condensed into liquid methanol after being sprayed through the nozzle under the low-temperature environment, so that the liquid methanol fuel is prevented from entering each cylinder to cause poor uniformity, and the combustion stability and the combustion uniformity of each cylinder are influenced.
The methanol delivery line is provided with a methanol check valve 10 for preventing the methanol vaporizer from generating methanol vapor in a reverse flow in an abnormal situation. A methanol one-way valve is arranged between the methanol vaporizer and the methanol fuel tank, and the purpose of the one-way valve is mainly to prevent the methanol vaporizer from generating higher methanol vapor under abnormal conditions to cause the methanol vapor to flow backwards, so that the pressure of the methanol fuel tank is higher. Meanwhile, due to the existence of the one-way valve, when the engine is stopped, the methanol in the vaporizer reflows to the methanol fuel tank due to the reduction of the pressure maintaining capacity in the methanol fuel tank, so that the vaporizer is dried due to the fact that the vaporizer is not filled with methanol liquid, certain methanol is always filled in the vaporizer in the process of starting the heat engine of the engine, and the methanol steam is pre-prepared in the heat engine stage.
A pressure reducing valve 19 and a pressure stabilizing valve 18 are sequentially arranged on an air inlet pipeline connected with the natural gas storage tank 1, the upper part of the methanol fuel tank is connected with the pressure stabilizing valve through a high-pressure pipeline, and the pressure stabilizing valve forms a natural gas pressure stabilizer; the methanol fuel supply system can be provided without a methanol electric pump, and the injection pressure of the methanol fuel is supplied by a natural gas high-pressure gas tank. The methanol fuel tank is a metal high-pressure resistant fuel tank which can bear the pressure of more than 1 MPa. A high-pressure pipeline is arranged above the methanol fuel tank and is connected with the outlet of a natural gas fuel tank voltage stabilizer, and the methanol fuel in the methanol fuel tank is pressurized by utilizing the high pressure (0.8-0.9 MPa) after the natural gas is decompressed, so that the pressure required when the methanol fuel enters the injection is ensured.
The methanol steam is sprayed by using one set of gas nozzle shared by the methanol steam and the natural gas, so that the methanol steam injection device is simple in structure, convenient to arrange and install and relatively low in cost.
The engine of the invention takes methanol fuel as main fuel, natural gas engine (CNG) as auxiliary fuel, and adopts dual fuel to supply fuel; when the engine is started at low temperature, natural gas is used as fuel, liquid methanol is heated by a vaporizer by using waste heat of waste gas after cooling liquid of the engine reaches a certain temperature, the liquid methanol is changed into methanol steam, and the methanol fuel enters a cylinder in a methanol steam mode for combustion.
The methanol fuel and the natural gas have very friendly complementarity, the two fuels are both one carbon atom and four hydrogen atoms in view of molecular formula, but the methanol is one more oxygen atom than the natural gas fuel, and as the fuel of the internal combustion engine, the methanol steam and the natural gas have many similar combustion characteristics, the anti-knock index octane numbers of the two fuels respectively reach 127 and 114, and the anti-knock property of the two fuels is higher than that of a gasoline engine, so that the compression ratio of the engine can be improved, and the two fuels can be premixed, diffused and combusted by adopting a spark plug ignition mode. The vaporization temperature of the natural gas is-162 ℃, so even in an extremely low winter environment, the natural gas can easily form uniform mixed gas with air, the low-temperature cold start is very good, and the defect of difficult low-temperature cold start of methanol can be overcome. The boiling point of the methanol fuel at normal pressure is 64.7 ℃, and the methanol fuel is easier to heat and vaporize into methanol steam. After methanol is vaporized, the methanol enters the cylinder in a gaseous state for combustion, the mode is completely the same as the mode of combustion of natural gas entering the cylinder, the same natural gas nozzle and an electric control system can be adopted, the two fuels adopt an equivalent mixed gas control mode, a three-way catalyst is adopted for emission aftertreatment, and the conversion efficiency of the emitted pollutants is higher. And the methanol steam injection mode avoids methanol entering the cylinder in a liquid state, which causes the problems of cylinder liner abrasion aggravation and engine oil dilution, and reduces the emission of unburned methanol and HC.
The control method of the two fuels of natural gas and methanol has three modes: the starting mode, the heat engine mode and the normal working mode are respectively adopted. In the starting mode, an electronic control cut-off valve of the methanol fuel supply system is closed, a natural gas electronic control cut-off valve is opened, the engine is cold started by adopting single natural gas, and because the vaporization pressure of the natural gas is-162 ℃, the natural gas is easy to form homogeneous mixed gas with air in a low-temperature environment, and the cold starting effect is good. After the engine is successfully started, the engine enters a heat engine mode, natural gas fuel is also adopted in the heat engine process, and the natural gas characteristic value MAP written by a control system is adopted for controlling the ignition angle and the fuel injection quantity of the engine. When the heat engine reaches a certain degree, the engine carries out condition judgment according to parameters such as ambient temperature, coolant temperature, methanol steam temperature and pressure, and if the conditions are met, the engine enters a normal working mode. The normal operating mode is at first opened the automatically controlled trip valve of methyl alcohol, guarantees that methyl alcohol steam enters into the common rail pipe, then breaks off the automatically controlled trip valve of natural gas again, because the common rail pipe can remain certain natural gas, has two kinds of fuel and participates in the transition operating mode of burning simultaneously, and the judgement condition whether transition operating mode is ended can be judged according to the closed loop feedback of air-fuel ratio. After the transition working condition is finished, the engine enters a methanol single fuel working mode, and the ignition angle and the fuel injection quantity are controlled by using the methanol characteristic values written by the control system.
Preferred embodiments of the present invention are:
the methanol and natural gas dual-fuel engine provided by the invention is provided with two sets of independent fuel tanks, a natural gas fuel supply system mainly comprises a natural gas storage tank 1, a pressure reducing valve 19, a pressure stabilizing valve 18, a natural gas cut-off valve 17, a methanol natural gas nozzle 15 and other components, and the methanol fuel supply system comprises: the device comprises a methanol fuel tank 2, a methanol steam buffer tank 3, a methanol vaporizer 9, a methanol one-way valve 10, a methanol cut-off valve 4, a common rail pipe 16 and the like. The Compressed Natural Gas (CNG) is stored in the natural gas storage tank, the pressure is generally 10-20MPa, the capacity of the natural gas storage tank does not need to be too large, the volume of the natural gas storage tank is generally 1/10 of the volume of the methanol fuel tank, the pressure of the compressed natural gas is reduced to about 1-2MPa after being reduced by a reducing valve, and then the pressure is stably controlled to be 0.7-0.8MPa through a pressure stabilizing valve.
The methanol fuel tank is connected with the pressure stabilizing valve through a high-pressure pipeline, and the pressure of the pressure stabilizing valve can be stably transmitted into the methanol fuel tank to provide pressure for methanol injection. The methanol vaporizer is arranged on the exhaust pipe in series, a waste gas bypass valve is arranged in the methanol vaporizer, the amount of high-temperature waste gas flowing through the vaporizer can be controlled by opening the valve, and the requirement for preparing methanol steam is met according to the flow demand of methanol under different working conditions. After methanol passes through the vaporizer, generated steam is temporarily stored in the buffer tank, and the volume of the methanol steam buffer tank is designed according to the displacement of the engine so as to meet the hysteresis effect of the methanol vaporizer for preparing methanol steam under the transient working condition. The common rail pipe is a device for collecting the natural gas and the methanol steam, and can balance the pressure stability before fuel injection. The nozzles are arranged on the common rail pipe connected with the air inlet end, the air outlet end is connected with the air inlet header pipe, and a single-point injection mode is adopted (according to the flow of the nozzles, a plurality of nozzles can be adopted if the flow of the nozzles is not enough, and the nozzles are connected in parallel between the air inlet header pipe and the common rail pipe).
The methanol vapor or natural gas fuel is mixed with the EGR waste gas and the fresh air in the EGR mixer 14, and the mixer is used for fully mixing the methanol vapor (or natural gas) fuel with the fresh air and the EGR waste gas to form a mixed gas with uniform temperature and concentration and then enters the air inlet pipe. The intake pipe main line is provided with the heating water jacket, and heating medium adopts the engine coolant liquid, and the coolant liquid is got from engine cooling system microcirculation, guarantees that the engine also has the function of preheating when the warm-up to avoid methyl alcohol steam before getting into the jar, in the intake pipe condensation for liquid methyl alcohol, influence the homogeneity that methyl alcohol fuel got into each jar, and then influence engine combustion stability. The EGR adopts a high-pressure EGR system, the EGR rate is controlled through an EGR valve, and the temperature of the exhaust gas after the EGR is cooled is controlled to be 100-120 ℃.
According to the difference of the external environment temperature and the engine coolant temperature, the engine is divided into three working condition modes of starting working condition, warming working condition and normal working condition. And the starting working condition and the warming working condition are both injected by adopting natural gas fuel. When the engine is started, the electronic control system sends instructions to the natural gas cut-off valve 17 and the methanol cut-off valve 4, the natural gas cut-off valve is opened, the methanol cut-off valve 4 is closed, compressed natural gas forms stable injection pressure in the common rail pipe after being regulated by the pressure reducing valve and the pressure stabilizing valve, and the injection pressure is generally regulated within the range of 0.7-0.8MPa to meet the requirement of natural gas injection. After the engine is started successfully, the engine enters a warm-up stage, and natural gas fuel injection is continuously adopted. At the moment, the methanol fuel tank transmits the pressure transmitted by the natural gas pressure stabilizer, the methanol in the methanol fuel tank is pressed into the methanol vaporizer, the vaporizer is arranged at a height lower than that of the methanol fuel tank, and even if the methanol cut-off valve is in a closed state, the liquid methanol can fill the methanol vaporizer under the action of gravity. In the warming-up stage, the vaporizer controls the opening of the waste gas bypass valve to be closed, and the waste gas is made to flow through the vaporizer completely to accelerate the vaporization speed of the methanol and rapidly prepare methanol steam. When the temperature of the cooling liquid rises to a certain temperature (generally 65 ℃), combining the methanol vapor pressure and the temperature condition of the methanol vapor buffer tank to determine whether the methanol vapor pressure is greater than 0.8MPa and the temperature is greater than 65 ℃), starting the engine in a normal working mode, sending an instruction to the methanol cut-off valve by the electronic control system at the moment, starting the methanol cut-off valve, then closing the natural gas cut-off valve, starting the two cut-off valves one by one, having a time difference, and optimizing and calibrating the specific time difference through calibration parameters so as to ensure the stability provided by the fuel and avoid the fluctuation of the rotating speed of the engine when the two fuels are switched. After entering a normal working mode, according to different theoretical air-fuel ratios of methanol, natural gas and air, the flow characteristic of the nozzle adopts the injection pulse width of methanol fuel, and other control parameters of an ignition angle are also switched to the parameters of the working condition of the methanol fuel.
The engine is under normal mode, because the engine has transient condition, and exhaust temperature is not stable, and methanol vapor is prepared and just has the unstable phenomenon of flow, for example when accelerating suddenly, and demand methanol vapor jet flow is great in the twinkling of an eye, and exhaust temperature preheats not enough this moment, and the large-traffic demand of transient condition methanol vapor can be compensatied to the methanol vapor buffer tank who consequently arranges. When the engine continuously works under a large load, the exhaust temperature is higher, the methanol vaporizer produces more methanol steam, the pressure and the temperature of the methanol buffer tank are increased, and the electronic control system can control a waste gas bypass valve in the methanol vaporizer to adjust the flow of high-temperature waste gas flowing through the vaporizer, so that the effect of controlling the methanol preparation flow of the vaporizer is achieved. In addition, a methanol one-way valve is arranged at a fuel inlet of the methanol vaporizer, and the one-way valve can prevent the methanol vapor backflow phenomenon caused by the fact that the vapor pressure in the methanol vaporizer exceeds the pressure in a methanol fuel tank.
The above-mentioned features are merely for describing preferred embodiments of the present invention and may be arbitrarily combined to form a plurality of embodiments of the present invention.
The invention is described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the above embodiments, and it is within the scope of the invention to use the concept and technical solution of the invention in other fields without substantial or direct modification.
Claims (10)
1. The utility model provides a methyl alcohol, natural gas dual-fuel engine, includes cylinder body, natural gas holder, methyl alcohol fuel tank, engine intake pipe, the engine intake pipe links to each other with the cylinder body, its characterized in that: the natural gas storage tank is connected with the common rail pipe through an air inlet pipeline, the methanol fuel tank is connected with the methanol vaporizer through a methanol conveying pipeline, and the methanol vaporizer is connected with the common rail pipe through a methanol steam conveying pipeline and a methanol steam buffer.
2. The methanol and natural gas dual-fuel engine as claimed in claim 1, characterized in that: the nozzle is arranged on an air inlet pipe of the engine to form a methanol steam fuel and natural gas fuel shared nozzle structure.
3. The methanol, natural gas dual-fuel engine as claimed in claim 1, characterized in that: the exhaust port of the cylinder body is connected with an exhaust pipe, and the methanol vaporizer is arranged on the exhaust pipe.
4. The methanol, natural gas dual-fuel engine as claimed in claim 1, characterized in that: and a heating water jacket for heating and insulating the air inlet pipe is arranged outside the air inlet pipe of the engine.
5. The methanol and natural gas dual-fuel engine as claimed in claim 1, characterized in that: and a methanol one-way valve for preventing the methanol vaporizer from generating methanol steam countercurrent is arranged on the methanol conveying pipeline under abnormal conditions.
6. The methanol, natural gas dual-fuel engine as claimed in claim 1, characterized in that: and a pressure reducing valve and a pressure stabilizing valve are sequentially arranged on an air inlet pipeline connected with the natural gas storage tank, and the upper part of the methanol fuel tank is connected with the pressure stabilizing valve through a high-pressure pipeline.
7. The methanol, natural gas dual-fuel engine as claimed in claim 2, characterized in that: the common rail pipe is of a three-way structure with two inlets and one outlet, the two inlets are respectively connected with the methanol steam buffer and the natural gas pressure stabilizing valve, and the outlet is connected with the nozzle.
8. The methanol, natural gas dual-fuel engine as claimed in claim 3, characterized in that: the methanol vaporizer is arranged at the rear end of the engine post-treatment three-way catalytic converter, high-temperature exhaust gas flows through the vaporizer in a full flow mode, an electric exhaust gas bypass valve is arranged in the methanol vaporizer, and closed-loop control is conducted on the opening of the bypass valve by detecting methanol steam temperature feedback.
9. The methanol, natural gas dual-fuel engine as claimed in claim 4, characterized in that: and the heating water jacket is connected with a small circulation of an engine cooling system.
10. A control method of a methanol and natural gas dual-fuel engine is characterized by comprising the following steps: the control method comprises the following steps: methanol fuel is used as main fuel, natural gas fuel is used as auxiliary fuel, a fuel supply mode is carried out by adopting dual fuel, natural gas fuel is adopted in starting and heat engine working conditions, and after the heat engine is finished, methanol steam is used as main fuel to enter a normal working mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211327579.3A CN115653748A (en) | 2022-10-27 | 2022-10-27 | Methanol and natural gas dual-fuel engine and control method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211327579.3A CN115653748A (en) | 2022-10-27 | 2022-10-27 | Methanol and natural gas dual-fuel engine and control method |
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| CN115653748A true CN115653748A (en) | 2023-01-31 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117028049A (en) * | 2023-10-07 | 2023-11-10 | 潍柴动力股份有限公司 | Cold start control method and related device for methanol engine |
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2022
- 2022-10-27 CN CN202211327579.3A patent/CN115653748A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117028049A (en) * | 2023-10-07 | 2023-11-10 | 潍柴动力股份有限公司 | Cold start control method and related device for methanol engine |
| CN117028049B (en) * | 2023-10-07 | 2024-01-16 | 潍柴动力股份有限公司 | Cold start control method and related device for methanol engine |
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