Methanol pyrolysis gas and liquid methanol blending combustion engine system and control method
By using the blending method of methanol cracking gas and liquid methanol in the engine, the blending ratio is adjusted and the catalyst and exhaust heat are used to generate hydrogen-rich gas, the problem of cold start of methanol engine and low torque power of methanol cracking gas is solved, and the engine is improved efficient thermal efficiency is achieved.
Patent Information
- Application Number
- CN202411723748.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-03-25
AI Technical Summary
The cold start problem of liquid methanol in the engine and the low torque and power of methanol cracking gas.
The blending ratio of methanol cracking gas and liquid methanol is adjusted under different engine operating conditions through the ECU control. The mixing ratio of methanol cracking gas and liquid methanol is generated under the action of catalyst and exhaust gas waste heat, and the mixture is mixed with liquid methanol to burn.
It effectively solves the cold start problem of methanol engine, improves the torque and power of methanol cracking gas, and improves the thermal efficiency of the engine.
Smart Images
Figure CN119686873A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of engine systems, and in particular to a methanol cracking gas and liquid methanol mixed combustion engine system and a control method. Background Art
[0002] The chemical formula of methanol is CH30H, and the oxygen atoms in it can effectively improve the combustion efficiency during the combustion process of the internal combustion engine, reduce unburned hydrocarbons and other substances, and achieve cleaner emissions. However, liquid methanol fuel has the characteristics of low saturated vapor pressure, large latent heat of vaporization, and is not easy to volatilize in low temperature environments. Therefore, its application in engines has poor methanol spray atomization performance, especially in winter when the ambient temperature is low, methanol will have problems with cold start due to poor atomization effect.
[0003] Liquid methanol can be cracked to generate H2 and CO to burn hydrogen-rich gas under the dual effects of catalyst and exhaust gas waste heat (or heating by methanol heating device). Methanol cracking gas itself is rich in H2, so it has combustion advantages such as wide ignition range and fast combustion speed. Its combustion application in the engine can effectively reduce combustion loss, improve combustion efficiency, and thus improve the effective thermal efficiency of the engine. At the same time, methanol cracking gas is liquid methanol that is cracked into H2 and CO hydrogen-rich gas under the support of catalyst by recovering the exhaust waste heat of the engine. Its fuel calorific value can be effectively increased by about 20%, the waste heat energy is recovered, and the overall effective efficiency of the engine is improved. Therefore, the application engine of methanol cracking gas has the advantage of high thermal efficiency. However, methanol cracking gas is a gaseous fuel, and its application in the engine has the problem of torque and power difference that needs to be solved urgently. Summary of the invention
[0004] The purpose of the present invention is to provide a methanol cracking gas and liquid methanol co-combustion engine system and a control method, which adopts a co-combustion application mode on the engine according to the fuel characteristics of liquid methanol and methanol cracking gas themselves, thereby solving the cold start problem of the liquid methanol engine and also improving the low torque and power problems of the methanol cracking gas engine.
[0005] To achieve the purpose of the present invention, the technical solution provided by the present invention is as follows:
[0006] First aspect
[0007] The present invention provides a methanol cracking gas and liquid methanol mixed combustion engine system, comprising an engine, a methanol tank, a methanol pump, a methanol heater, a methanol cracking device, a cooler, and a cracking gas storage tank;
[0008] The methanol tank is connected to a methanol pump, the methanol pump is connected to an engine, connected to a methanol heater via a pipeline provided with a valve V1, and connected to a methanol cracking device via a pipeline provided with a valve V2;
[0009] The methanol cracking device is connected to a cooler, the cooler is connected to a methanol tank through a pipeline, and is connected to a cracked gas storage tank through a pipeline, and the cracked gas storage tank is connected to an engine.
[0010] Further, the engine system performs the following method, which includes the following steps:
[0011] Step 1: Cold start condition, specifically as follows: ECU determines that the engine operating condition is cold start, then ECU controls to open the methanol cracking gas, H2 and CO start to be injected, the spark plug ignites, and the engine starts successfully; while the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, and methanol heater starts to be supplied with methanol, and the methanol heater starts to work to provide exhaust gas heat to heat the methanol cracking unit; at this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank, and the methanol nozzle is not working;
[0012] Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in the warm-up condition; in the warm-up condition, the methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle, and its energy ratio accounts for only 10%;
[0013] Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions. Under normal engine operating conditions, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so the methanol heater is turned off under this condition, and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, methanol The steam condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; the engine operates with different cracked gas and liquid methanol blending ratios under different operating conditions. Under low load conditions, the engine operates with a blending ratio of 70% cracked gas and 30% liquid methanol; under medium load conditions, the engine operates with a blending ratio of 80% methanol cracked gas and 20% liquid methanol; under high load conditions, the engine operates with a blending ratio of 50% methanol cracked gas and 50% liquid methanol; under acceleration conditions, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracked gas is 80%:20%.
[0014] Furthermore, the ECU determines the engine operating condition according to the engine speed, torque, water temperature and oil temperature.
[0015] Second aspect
[0016] The present invention provides a method for controlling a methanol cracking gas and liquid methanol mixed combustion engine system, wherein the engine system adopts the above-mentioned methanol cracking gas and liquid methanol mixed combustion engine system, and the method comprises the following steps:
[0017] Step 1: Cold start condition, specifically as follows: ECU determines that the engine operating condition is cold start, then ECU controls to open the methanol cracking gas, H2 and CO start to be injected, the spark plug ignites, and the engine starts successfully; while the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, and methanol heater starts to be supplied with methanol, and the methanol heater starts to work to provide exhaust gas heat to heat the methanol cracking unit; at this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank, and the methanol nozzle is not working;
[0018] Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in the warm-up condition; in the warm-up condition, the methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle, and its energy ratio accounts for only 10%;
[0019] Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions. Under normal engine operating conditions, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so the methanol heater is turned off under this condition, and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, methanol The steam condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; the engine operates with different cracked gas and liquid methanol blending ratios under different operating conditions. Under low load conditions, the engine operates with a blending ratio of 70% cracked gas and 30% liquid methanol; under medium load conditions, the engine operates with a blending ratio of 80% methanol cracked gas and 20% liquid methanol; under high load conditions, the engine operates with a blending ratio of 50% methanol cracked gas and 50% liquid methanol; under acceleration conditions, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracked gas is 80%:20%.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] The present invention adopts the method of online preparation of cracking gas from liquid methanol and combustion of the mixed liquid methanol, which not only solves the cold start problem of the methanol engine, but also effectively recovers the waste heat of the engine to improve the calorific value of the fuel and thus improve the thermal efficiency of the engine. In addition, the use of hydrogen-rich methanol cracking gas for auxiliary combustion can effectively increase the combustion speed and improve the thermal efficiency of the engine. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic diagram of the structure of an engine system provided in an embodiment of the present application;
[0023] Figure 2 A schematic diagram of the mixing ratio under different operating conditions of the engine provided in the embodiment of the present application;
[0024] Figure 3 A schematic diagram of the normal operating conditions of an engine provided in an embodiment of the present application. DETAILED DESCRIPTION
[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0026] Methanol heater: It uses methanol as fuel, ignites and burns to heat the cooling medium, and circulates in the entire engine cooling system under the action of the built-in circulating water pump of the methanol heater to achieve the purpose of heating the cooling water and quickly warming up the engine. At the same time, the waste heat of the heater's exhaust gas can heat the methanol cracking unit.
[0027] Methanol cracking unit: Liquid methanol is sprayed into the methanol cracking unit through the methanol tank, methanol pump, methanol pipeline and methanol nozzle. It is heated by the waste heat of the exhaust gas in the methanol cracking unit and gasified into methanol vapor. Then, it is cracked into hydrogen, carbon monoxide and hydrogen-rich gas of methanol vapor under the support of the catalyst.
[0028] like Figure 1-Figure 3 As shown, an embodiment of the present invention provides a methanol cracking gas and liquid methanol blended combustion engine system, including an engine, a methanol tank, a methanol pump, a methanol heater, a methanol cracking device, a cooler, and a cracking gas storage tank;
[0029] The methanol tank is connected to a methanol pump, the methanol pump is connected to an engine, connected to a methanol heater via a pipeline provided with a valve V1, and connected to a methanol cracking device via a pipeline provided with a valve V2; the methanol cracking device is connected to a cooler, the cooler is connected to the methanol tank via a pipeline, connected to a cracked gas storage tank via a pipeline, and the cracked gas storage tank is connected to the engine.
[0030] Further, the engine system performs the following method, which includes the following steps:
[0031] Step 1: Cold start condition, as follows: ECU determines that the engine operating condition is a cold start according to parameters such as engine speed, torque, water temperature and oil temperature. Then, ECU controls to open the methanol cracking gas, H2 and CO start to be injected, spark plug ignites, and the engine starts successfully. While the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, methanol is supplied to the methanol heater, and the methanol heater starts working to provide exhaust gas heat to heat the methanol cracking unit. At this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank. At the same time, because the engine water temperature is also very low, liquid methanol is not easy to atomize, and the methanol nozzle is not working.
[0032] Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in warm-up condition based on parameters such as engine speed, torque, water temperature and oil temperature; in warm-up condition, the engine water temperature and oil temperature are relatively low, and the exhaust gas heat is also relatively low. The methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time, shortening the heating time of the methanol cracker. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle. Its energy ratio is only 10%, and the atomization performance of methanol can be well guaranteed;
[0033] Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions based on parameters such as engine speed, torque, water temperature and oil temperature. Under normal operating conditions of the engine, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so under this condition, the methanol heater is turned off and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, the methanol vapor condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; in order to ensure the normal operation and optimal operating performance of the engine, the engine is operated with different cracked gas and liquid methanol mixing ratios under different working conditions. Among them, the engine operates at different cracking gas and liquid methanol blending ratios under different operating conditions. Under the A1 small load condition, it operates at a blending ratio of 70% cracking gas and 30% liquid methanol; under the A2 medium load condition, it operates at a blending ratio of 80% methanol cracking gas and 20% liquid methanol; under the A3 large load condition, it operates at a blending ratio of 50% methanol cracking gas and 50% liquid methanol; under acceleration conditions, in order to ensure acceleration performance, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracking gas is 80%:20%.
[0034] The present invention constructs a methanol cracking gas and liquid methanol mixed combustion system, which can realize online production of methanol cracking gas, recover waste heat, and improve the calorific value of fuel. Moreover, within the entire engine operating condition range, the ratio of cracking gas and liquid methanol can be flexibly controlled according to the engine operating condition characteristics, so as to optimize the engine performance.
[0035] Second aspect
[0036] The present invention provides a method for controlling a methanol cracking gas and liquid methanol mixed combustion engine system, wherein the engine system adopts the above-mentioned methanol cracking gas and liquid methanol mixed combustion engine system, and the method comprises the following steps:
[0037] Step 1: Cold start condition, specifically as follows: ECU determines that the engine operating condition is cold start, then ECU controls to open the methanol cracking gas, H2 and CO start to be injected, the spark plug ignites, and the engine starts successfully; while the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, and methanol heater starts to be supplied with methanol, and the methanol heater starts to work to provide exhaust gas heat to heat the methanol cracking unit; at this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank, and the methanol nozzle is not working;
[0038] Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in the warm-up condition; in the warm-up condition, the methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle, and its energy ratio accounts for only 10%;
[0039] Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions. Under normal engine operating conditions, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so the methanol heater is turned off under this condition, and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, methanol The steam condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; the engine operates with different cracked gas and liquid methanol blending ratios under different operating conditions. Under low load conditions, the engine operates with a blending ratio of 70% cracked gas and 30% liquid methanol; under medium load conditions, the engine operates with a blending ratio of 80% methanol cracked gas and 20% liquid methanol; under high load conditions, the engine operates with a blending ratio of 50% methanol cracked gas and 50% liquid methanol; under acceleration conditions, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracked gas is 80%:20%.
[0040] Finally, it should be noted that the above embodiments are only used to illustrate and explain the present invention, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention.
Claims
1. A methanol cracking gas and liquid methanol mixed combustion engine system, characterized in that: It includes engine, methanol tank, methanol pump, methanol heater, methanol cracking unit, cooler and cracking gas storage tank; The methanol tank is connected to a methanol pump, the methanol pump is connected to an engine, connected to a methanol heater via a pipeline provided with a valve V1, and connected to a methanol cracking device via a pipeline provided with a valve V2; The methanol cracking device is connected to a cooler, the cooler is connected to a methanol tank through a pipeline, and is connected to a cracked gas storage tank through a pipeline, and the cracked gas storage tank is connected to an engine.
2. The methanol cracking gas and liquid methanol mixed combustion engine system according to claim 1, characterized in that: The engine system performs the following method, which includes the following steps: Step 1: Cold start condition, specifically as follows: ECU determines that the engine operating condition is cold start, then ECU controls to open the methanol cracking gas, H2 and CO start to be injected, the spark plug ignites, and the engine starts successfully; while the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, and methanol heater starts to be supplied with methanol, and the methanol heater starts to work to provide exhaust gas heat to heat the methanol cracking unit; at this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank, and the methanol nozzle is not working; Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in the warm-up condition; in the warm-up condition, the methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle, and its energy ratio accounts for only 10%; Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions. Under normal engine operating conditions, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so the methanol heater is turned off under this condition, and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, methanol The steam condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; the engine operates with different cracked gas and liquid methanol blending ratios under different operating conditions. Under low load conditions, the engine operates with a blending ratio of 70% cracked gas and 30% liquid methanol; under medium load conditions, the engine operates with a blending ratio of 80% methanol cracked gas and 20% liquid methanol; under high load conditions, the engine operates with a blending ratio of 50% methanol cracked gas and 50% liquid methanol; under acceleration conditions, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracked gas is 80%:20%.
3. The methanol cracking gas and liquid methanol mixed combustion engine system according to claim 2, characterized in that: The ECU determines the engine operating condition according to the engine speed, torque, water temperature and oil temperature.
4. A method for controlling a methanol cracking gas and liquid methanol blended combustion engine system, characterized in that: The engine system adopts a methanol cracking gas and liquid methanol mixed combustion engine system as claimed in claim 1, and the method comprises the following steps: Step 1: Cold start condition, specifically as follows: ECU determines that the engine operating condition is cold start, then ECU controls to open the methanol cracking gas, H2 and CO start to be injected, the spark plug ignites, and the engine starts successfully; while the engine is starting, ECU also controls the methanol pump to start working, V1 control is turned on, and methanol heater starts to be supplied with methanol, and the methanol heater starts to work to provide exhaust gas heat to heat the methanol cracking unit; at this time, the methanol cracking unit does not have enough heat to crack methanol to generate H2 and CO, so the methanol gas-liquid engine uses the gas in the cracking gas storage tank, and the methanol nozzle is not working; Step 2: Warm-up condition, as follows: the engine has been successfully started, but the ECU determines that the engine is in the warm-up condition; in the warm-up condition, the methanol cracker still cannot work normally, so V2 is still in the closed state. At this time, the exhaust heat of the methanol heater and the heat of the engine exhaust gas heat the methanol cracker at the same time. Under this condition, the engine fuel is supplied by 90% cracking gas and 10% liquid methanol. The methanol cracking gas comes entirely from the cracking gas storage tank, and the liquid methanol comes from the engine methanol direct injection nozzle, and its energy ratio accounts for only 10%; Step 3: Normal operating conditions, as follows: ECU determines that the engine is operating under normal operating conditions. Under normal engine operating conditions, after cold start and warm-up conditions, the temperature of the methanol cracking unit is suitable for methanol cracking, so V2 is opened, and the methanol pump supplies methanol to the methanol cracking unit. The exhaust heat of the engine can fully support methanol hydrogen production under this condition, so the methanol heater is turned off under this condition, and V1 is turned off. Liquid methanol is gasified, evaporated and cracked into H2 and CO in the methanol cracking unit. At the same time, a part of the uncracked methanol vapor enters the cooler along the pipeline. Under the action of the cooler, methanol The steam condenses into liquid methanol and flows back to the methanol tank for recycling; H2 and CO enter the cracked gas storage tank for storage for future use; the engine operates with different cracked gas and liquid methanol blending ratios under different operating conditions. Under low load conditions, the engine operates with a blending ratio of 70% cracked gas and 30% liquid methanol; under medium load conditions, the engine operates with a blending ratio of 80% methanol cracked gas and 20% liquid methanol; under high load conditions, the engine operates with a blending ratio of 50% methanol cracked gas and 50% liquid methanol; under acceleration conditions, direct injection of liquid methanol is required to increase the ratio, so the blending ratio of liquid methanol and cracked gas is 80%:20%.