CN117685137A

CN117685137A - Marine double-direct injection engine system and control method thereof

Info

Publication number: CN117685137A
Application number: CN202311542789.9A
Authority: CN
Inventors: 张尊华; 魏峰; 李格升
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2023-11-16
Filing date: 2023-11-16
Publication date: 2024-03-12

Abstract

The invention discloses a marine double-direct injection engine system and a control method thereof, which are applied to the technical field of engines, can realize clean, efficient and controllable combustion of the engines in a wide working condition range, and effectively relieve the problem of limited operation working conditions. The system comprises: a methanol supply module for supplying methanol; a diesel supply module for providing diesel; the engine comprises an intake manifold, an exhaust manifold and a fuel input end, and is used for burning input diesel oil and methanol; the methanol cracking module comprises a cracking input end and a cracking output end, and is used for carrying out a cracking reaction on input methanol to obtain methanol cracking gas, and inputting the methanol cracking gas into the engine through an intake manifold; the exhaust gas recirculation module comprises an exhaust gas input end, a first exhaust gas output pipeline and a second exhaust gas output pipeline, wherein the exhaust gas input end is connected with an exhaust manifold, the first exhaust gas output pipeline is connected with an intake manifold, and the second exhaust gas output pipeline is used for discharging exhaust gas generated by an engine.

Description

Marine double-direct injection engine system and control method thereof

Technical Field

The invention relates to the technical field of engines, in particular to a marine double-direct injection engine system and a control method thereof.

Background

Methanol has the characteristics of low carbon, high octane number, high oxygen content, low pollution, no smoke exhaust and the like, and is gradually accepted by the shipping industry as an ideal novel clean renewable fuel. At present, the main application mode of the methanol fuel in the marine engine is DMCC mode, namely methanol is injected from an air inlet pipe, and diesel oil is directly injected to ignite the methanol mixed gas. However, in the DMCC mode, the methanol substitution rate is severely limited by the operating conditions, and it is difficult to achieve a high methanol substitution rate in a wide operating range under conditions in which reliable ignition and stable combustion of the mixture are ensured. In addition, methanol has high vaporization latent heat and high flame propagation speed, and has complex interaction with diesel oil, excessive mixing of fuel and air is easy to occur under low load, rough combustion is easy to occur under high load, and clean, efficient and controllable combustion in the whole working condition range is difficult to realize. Therefore, the above technical problems need to be solved.

Disclosure of Invention

In order to solve at least one of the technical problems, the invention provides a marine double-direct injection engine system and a control method thereof, which can realize clean, efficient and controllable combustion of an engine in a wide working condition range and effectively relieve the problem of limited operation working conditions.

In one aspect, an embodiment of the present invention provides a dual direct injection engine system for a ship, including:

a methanol supply module for providing methanol;

a diesel supply module for providing diesel;

the engine comprises an air inlet manifold, an air outlet manifold and a fuel input end, wherein the fuel input end is respectively connected with the methanol supply module and the diesel supply module, and the engine is used for combusting the input diesel and the input methanol;

the methanol cracking module comprises a cracking input end and a cracking output end, the cracking input end is connected with the methanol supply module, the cracking output end is connected with the air inlet manifold, and the methanol cracking module is used for carrying out cracking reaction on the input methanol to obtain methanol cracking gas and inputting the methanol cracking gas into the engine through the air inlet manifold;

the exhaust gas recirculation module comprises an exhaust gas input end, a first exhaust gas output pipeline and a second exhaust gas output pipeline, wherein the exhaust gas input end is connected with the exhaust manifold, the first exhaust gas output pipeline is connected with the air inlet manifold, and the second exhaust gas output pipeline is used for discharging exhaust gas generated by the engine.

According to some embodiments of the invention, the methanol supply module includes:

a methanol tank for storing and outputting the methanol;

the device comprises a methanol tank, a preset methanol pump, a control unit and a control unit, wherein the preset methanol pump comprises a methanol pump input end and a methanol pump output end, the methanol pump input end is connected with the methanol tank, and the preset methanol pump is used for providing pressure for the methanol tank so as to output methanol in the methanol tank;

the first stop valve comprises a first stop input end and a first stop output end, the first stop input end is connected with the output end of the methanol pump, and the first stop valve is used for controlling a first working state of the methanol supply module;

the methanol flowmeter comprises a first flowmeter input end and a first flowmeter output end, the first flowmeter input end is connected with the first cut-off output end, and the methanol flowmeter is used for measuring and adjusting the output quantity of the methanol;

the methanol common rail submodule comprises a first common rail input end and a first common rail output end, the first common rail input end is connected with the first flowmeter output end, and the methanol common rail submodule is used for controlling and adjusting a methanol output state;

The methanol injector comprises a methanol injection end and a first injector input end, wherein the first injector input end is connected with the first common rail output end, and the methanol injection end is used for injecting the methanol into a cylinder of the engine.

According to some embodiments of the invention, the diesel supply module comprises:

chai Youguan said diesel tank for storing and outputting said diesel;

the diesel engine comprises a diesel engine, a diesel tank, a preset diesel pump and a control unit, wherein the preset diesel pump comprises a diesel pump input end and a diesel pump output end, the diesel pump input end is connected with the diesel tank, and the preset diesel pump is used for providing pressure for the diesel tank so as to output diesel in the diesel tank;

the second stop valve comprises a second stop input end and a second stop output end, the second stop input end is connected with the diesel pump output end, and the second stop valve is used for controlling a second working state of the diesel supply module;

the diesel flowmeter comprises a second flowmeter input end and a second flowmeter output end, the second flowmeter input end is connected with the second cut-off output end, and the diesel flowmeter is used for measuring and adjusting the output quantity of the diesel;

The diesel common rail submodule comprises a second common rail input end and a second common rail output end, the second common rail input end is connected with the second flowmeter output end, and the diesel common rail submodule is used for controlling and adjusting a diesel output state;

the diesel injector comprises a diesel injection end and a second injector input end, wherein the second injector input end is connected with the second common rail output end, and the diesel injection end is used for injecting diesel into a cylinder of the engine.

According to some embodiments of the invention, the system further comprises:

the turbocharger comprises a first air inlet end, a first air outlet end, a second air inlet end and a second air outlet end, wherein the second air inlet end is connected with the second waste gas output pipeline, the first air inlet end is used for inputting air, and the second air outlet end is used for discharging waste gas;

the exhaust gas air mixer comprises a first mixing input end, a second mixing input end and a first mixing output end, wherein the first mixing input end is connected with the first air outlet end, the second mixing input end is connected with the first exhaust gas output pipeline through an exhaust gas circulation valve, and the exhaust gas air mixer is used for mixing air acquired by the turbocharger with exhaust gas to obtain first mixed gas;

The methanol pyrolysis gas mixer comprises a third mixing input end, a fourth mixing input end and a second mixing output end, wherein the third mixing input end is connected with the first mixing output end, the fourth mixing input end is connected with the pyrolysis output end through a pyrolysis gas valve, and the methanol pyrolysis gas mixer is used for mixing the first mixing gas with the methanol pyrolysis gas to obtain target mixing gas;

the intercooler comprises an intercooler input end and an intercooler output end, wherein the intercooler input end is connected with the second mixed output end, the intercooler output end is connected with the intake manifold, and the intercooler is used for cooling the target mixed gas.

On the other hand, the embodiment of the invention also provides a control method of the marine double-direct injection engine system, which is applied to the control system of the marine double-direct injection engine system and comprises the following steps:

acquiring preset engine parameters; the preset engine parameters comprise engine speed, expected engine power and rated engine power;

determining an engine working condition mode according to the engine rotating speed, the expected engine power and the rated engine power;

Controlling the working state of a preset control module according to the working condition mode of the engine so as to adjust the running state of the engine; the preset control module comprises a methanol cracking module, an exhaust gas recirculation module, a methanol supply module and a diesel supply module.

According to some embodiments of the invention, the determining the engine operating mode according to the engine speed, the desired engine power, and the rated engine power comprises:

when the engine rotating speed is determined to be zero, determining that the engine working condition mode is a cold start working mode;

or when the engine rotating speed is determined to be not zero and the expected power of the engine is smaller than or equal to a first threshold value of the rated power of the engine, determining that the engine working condition mode is a low-load working condition mode;

or when the engine rotating speed is determined to be not zero, the expected engine power is greater than the first threshold value, and the expected engine power is smaller than or equal to a second threshold value of the rated engine power, and the engine working condition mode is determined to be a medium-load working condition mode;

or when the engine rotating speed is determined to be not zero, the expected power of the engine is larger than the second threshold value, and the engine working condition mode is determined to be a high-load working condition mode.

According to some embodiments of the invention, the controlling the working state of the preset control module according to the working condition mode of the engine to adjust the running state of the engine includes:

when the engine working condition mode is determined to be the cold start working mode, closing the exhaust gas recirculation module, and controlling the diesel supply module to output diesel to an engine;

and controlling the methanol supply module to output methanol to the methanol cracking module so as to carry out methanol cracking reaction to obtain methanol cracking gas, and inputting the methanol cracking gas into the engine.

According to some embodiments of the invention, the controlling the working state of the preset control module according to the working condition mode of the engine to adjust the running state of the engine further includes:

when the engine working condition mode is determined to be the low-load working condition mode, controlling the methanol cracking module, the diesel oil supply module and the methanol supply module to be started;

adjusting injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol mixing limited combustion mode;

adjusting a first injection parameter, a methanol cracking hydrogen production rate and a methanol energy ratio according to preset engine parameters; the first injection parameters comprise methanol injection time and diesel injection time;

And controlling the secondary opening of an inlet valve of the engine according to a preset valve control rule so as to perform internal exhaust gas recirculation operation.

when the engine working condition mode is determined to be the medium-load working condition mode, controlling the exhaust gas recirculation module, the methanol cracking module, the diesel oil supply module and the methanol supply module to be started;

adjusting injection timing of the diesel supply module and the methanol supply module to control the engine to work in a methanol homogeneous charge premixed combustion mode;

adjusting a first injection parameter, a methanol cracking hydrogen production rate, a methanol energy ratio and an exhaust gas recirculation rate according to preset output parameters; the first injection parameters comprise methanol injection time and diesel injection time.

When the engine working condition mode is determined to be the high-load working condition mode, controlling the exhaust gas recirculation module, the diesel oil supply module and the methanol supply module to be started;

adjusting injection timing of the diesel supply module and the methanol supply module to control the engine to work in a methanol partial premix combustion mode;

adjusting a second injection parameter and an exhaust gas recirculation rate according to a preset output parameter; the second injection parameters comprise a primary methanol injection proportion, a secondary methanol injection proportion, a methanol injection moment and a diesel injection moment.

According to the marine double-direct injection engine system and the control method thereof, the marine double-direct injection engine system at least has the following beneficial effects: according to the embodiment of the invention, the methanol supply module and the diesel supply module are controlled to flexibly control the combustion mode and the fuel ratio of the engine, so that the requirements of different navigation working conditions can be met. Meanwhile, the embodiment of the invention carries out external exhaust gas recirculation through the exhaust gas recirculation module so as to regulate and control the combustion rate, reduce the combustion rate and prevent the detonation pressure from exceeding the limit and knocking. Furthermore, the embodiment of the invention carries out pyrolysis on the input methanol through the methanol pyrolysis module so as to realize the hydrogen-doped combustion of the methanol pyrolysis and effectively accelerate the combustion rate. It is easy to understand that the embodiment of the invention can regulate and control the combustion rate on the basis of realizing high methanol substitution rate by combining the methanol cracking module and the exhaust gas recirculation module, thereby realizing clean, efficient and controllable combustion of the engine in a wide working condition range and effectively relieving the problem of limited operation working conditions.

Drawings

FIG. 1 is a schematic diagram of a marine dual direct injection engine system according to an embodiment of the present invention;

FIG. 2 is a flow chart of a control method of the marine dual direct injection engine system provided by the embodiment of the invention;

FIG. 3 is a schematic diagram of a methanol mixing limited combustion mode provided by an embodiment of the present invention;

FIG. 4 is a schematic view of a secondary opening of an intake valve provided by an embodiment of the present invention;

FIG. 5 is a schematic illustration of a methanol homogeneous charge premixed combustion mode provided by an embodiment of the invention;

FIG. 6 is a schematic diagram of a partially premixed combustion mode of methanol according to an embodiment of the invention.

Detailed Description

The embodiments described in the present application should not be construed as limitations on the present application, but rather as many other embodiments as possible without inventive faculty to those skilled in the art, are intended to be within the scope of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

Before describing embodiments of the present application, related terms referred to in the present application will be first described.

Exhaust gas recirculation (Exhaust Gas Recirculation, EGR): the engine emission control technology is used for realizing the control of the combustion rate by reintroducing part of exhaust gas into an engine system to replace part of fresh air, thereby improving the engine performance. Among them, exhaust gas recirculation techniques include external exhaust gas recirculation and internal exhaust gas recirculation. Correspondingly, external exhaust gas recirculation refers to that part of discharged exhaust gas is re-introduced into an engine air inlet channel for recycling after being intercooled, so that the effects of reducing combustion temperature and reducing nitrogen oxide discharge are achieved. In addition, internal exhaust gas recirculation means that exhaust gas generated by controlling a valve mechanism is re-sucked or remained in a cylinder, thereby raising the temperature of the in-cylinder mixture and promoting the progress of combustion.

Methanol cracking technology: refers to a chemical reaction in which methanol molecules are heated to a high temperature and decomposed into carbon monoxide and hydrogen under the action of a catalyst.

Based on the above, one embodiment of the invention provides a marine double-direct injection engine system, which can realize clean, efficient and controllable combustion of an engine in a wide working condition range and effectively relieve the problem of limited operation working conditions. Referring to fig. 1, the marine dual direct injection engine system in this embodiment includes a methanol supply module, a diesel supply module, an engine, a methanol cracking module, and an exhaust gas recirculation module. Specifically, the methanol supply module in the embodiment of the invention is used for supplying methanol to the engine and the methanol cracking module. In addition, the diesel supply module is used for providing diesel for the engine in the embodiment of the invention. Accordingly, the engine of the present embodiment includes an intake manifold 171, an exhaust manifold 172, and a fuel input. In the embodiment of the invention, the methanol supply module and the diesel supply module are both connected with the fuel input end of the engine so as to input the methanol in the methanol supply module and the diesel in the diesel supply module into the engine for combustion. Further, the methanol cracking module in the embodiment of the invention comprises a cracking input end and a cracking output end. In this embodiment of the present invention, the methanol cracking input end is connected to the methanol supply module, so that the methanol stored in the methanol supply module is introduced into the methanol cracking module to perform a methanol cracking reaction, and a methanol cracking mixed gas, such as a mixed gas of hydrogen and carbon monoxide, is generated. Correspondingly, in the embodiment of the invention, the cracking output end of the methanol cracking module is connected with the air inlet manifold 171 of the engine so as to guide the methanol cracking mixed gas obtained by cracking into the engine, thereby realizing hydrogen-doped combustion and accelerating the combustion speed. In addition, the methanol cracking module in the embodiment of the invention further comprises a methanol cracking reactor 190 and a catalyst pipeline 191, wherein the methanol in the methanol supply module is input into the methanol cracking reactor 190 through the third stop valve 143 and the methanol bypass flowmeter 210, and is combined with a cracking reaction catalyst provided by the catalyst pipeline 191, so that the methanol cracking reaction is realized, and the methanol cracking gas is generated. Further, the exhaust gas recirculation module in the embodiment of the present invention includes an exhaust gas input, a first exhaust gas output line 221, and a second exhaust gas output line 223. Specifically, in embodiments of the present invention, the exhaust gas input is coupled to an exhaust manifold 172 of the engine to direct exhaust gas generated by combustion in the engine to the exhaust gas recirculation module. The embodiment of the invention provides heat for the methanol cracking reaction in the methanol cracking module through the waste heat of the waste gas passing through the first waste gas output pipeline of the methanol cracking module. Meanwhile, in the embodiment of the present invention, the first exhaust gas output pipe 221 is connected to the intake manifold 171 to re-introduce part of the exhaust gas into the engine, thereby forming external exhaust gas recirculation, and the cooled exhaust gas is partially introduced into the engine to participate in the combustion cycle of the engine, thereby regulating the combustion rate. In addition, in the embodiment of the present invention, the first exhaust gas output line 221 is connected to the exhaust manifold 172, and an exhaust branch is provided to discharge the exhaust gas other than the part of the exhaust gas introduced into the engine in the first exhaust gas output line 221. Meanwhile, in the embodiment of the invention, the second exhaust gas output pipeline is used for discharging exhaust gas generated by the engine.

In the working process of the specific embodiment, the embodiment of the invention can adapt to the power demands of different sailing working conditions by controlling the methanol supply module and the diesel supply module to regulate and control the combustion mode and the fuel ratio according to the control of the injection time sequence of the methanol and the diesel. Meanwhile, the embodiment of the invention introduces the exhaust gas recirculation module, comprising the internal EGR, the external EGR and the methanol cracking module, namely the methanol cracking technology, so that the combustion efficiency under different working conditions can be effectively improved, and the conventional and unconventional emission can be reduced. The external exhaust gas circulation in the embodiment of the invention is realized through the pipeline configuration of the exhaust gas recirculation module, and the internal exhaust gas recirculation is realized through the control valve law. Illustratively, the embodiment of the invention is executed in a pure diesel mode in a cold start first cycle stage, so that the problem of difficult cold start of methanol can be relieved. Correspondingly, under the low-load working condition, the embodiment of the invention improves the in-cylinder thermodynamic state by applying a methanol mixing limited combustion mode (MMLC) and introducing internal hot EGR, improves the exhaust temperature, and simultaneously realizes methanol pyrolysis and hydrogen loading by utilizing the waste heat of the tail gas of the engine so as to accelerate the combustion rate. Further, under the medium load working condition, the embodiment of the invention can regulate and control the combustion rate on the basis of realizing high methanol substitution rate by applying a methanol homogeneous charge premixed combustion Mode (MHCC) and combining an external EGR and methanol cracking technology. Then, under the high-load working condition, the embodiment of the invention can realize the high-load controllable combustion by applying a methanol partial premix combustion Mode (MPCC) and adopting premix ratio control and an external EGR technology. According to the embodiment of the invention, the methanol supply module, the diesel oil supply module, the methanol cracking module and the exhaust gas recirculation module are controlled and regulated by the rotating speed and the power information of the engine, so that clean, efficient and controllable combustion in a wide working condition range can be realized, and the problem of limited operation working conditions is effectively solved.

Referring to fig. 1, in some embodiments of the present invention, the methanol supply module includes a methanol tank 111, a methanol flow meter 121, a preset methanol pump 131, a first shut-off valve 141, a methanol common rail sub-module 151, and a preset methanol injector 161. Specifically, the methanol tank 111 is used for storing and outputting methanol in the embodiment of the present invention. Accordingly, the preset methanol pump 131 in the embodiment of the present invention includes a methanol pump input end and a methanol pump output end, and the methanol pump input end is connected to the methanol tank 111. Accordingly, in the embodiment of the present invention, the methanol in the methanol tank 111 is input to the engine through the preset methanol pump 131, that is, the methanol in the methanol tank 111 is pumped into the pipeline by providing the pressure through the preset methanol pump 131, and then is input to the engine. Further, the first stop valve 141 in the embodiment of the present invention includes a first stop input end and a first stop output end, where the first stop input end is connected to the methanol pump output end of the preset methanol pump 131. The first operating state of the methanol supply module is controlled through the first shut-off valve 141. For example, when the first shut-off valve 141 is opened, methanol in the methanol supply module may be normally input into the engine, i.e., in an operating state, whereas when the first shut-off valve 141 is closed, methanol in the methanol supply module may not be input into the engine, and is in a closed state. Accordingly, in an embodiment of the present invention, the methanol flow meter 121 includes a first flow meter input end and a first flow meter output end, where the first flow meter input end is connected to the first flow meter output end of the methanol flow meter 121. The embodiment of the present invention measures and adjusts the methanol output of the methanol tank 111 through the methanol flow meter 121. Further, in an embodiment of the present invention, the methanol common rail submodule 151 includes a first common rail input terminal and a first common rail output terminal. Wherein the first common rail input is connected to the first flowmeter output. The embodiment of the invention controls and adjusts the methanol output state through the methanol common rail sub-module 151. For example, the methanol common rail sub-module 151 of the embodiment of the invention ensures the stability and accuracy of fuel supply by controlling the operation pressure of the preset methanol pump 131, so as to improve the combustion efficiency and performance of the engine. Further, the embodiment of the present invention injects the methanol in the methanol common rail sub-module 151 into the cylinder of the engine through the preset methanol injector 161. In this embodiment of the present invention, the preset methanol injector 161 includes a methanol injection end and a first injector input end, where the first injector input end is connected to the first common rail output end of the methanol common rail sub-module 151, so as to introduce the methanol in the methanol common rail sub-module 151 into the preset methanol injector 161, and further inject the methanol into the engine cylinder 170 through the methanol injection end.

Referring to FIG. 1, in some embodiments of the invention, the diesel supply module includes a diesel tank 112, a diesel flow meter 122, a preset diesel pump 132, a second shut-off valve 142, a diesel common rail sub-module 152, and a preset diesel injector 162. Specifically, embodiments of the present invention store and output diesel via the diesel tank 112. Next, in the embodiment of the present invention, the preset diesel pump 132 includes a diesel pump input end and a diesel pump output end, and the diesel pump input end is connected to the diesel tank 112, so as to provide pressure for the diesel tank 112 through the preset diesel pump 132, and pump the diesel into the pipeline for further guiding into the engine. Further, the second shut-off valve 142 in the embodiment of the present invention includes a second shut-off input terminal and a second shut-off output terminal. In the embodiment of the present invention, the second cutoff input end is connected to the diesel pump output end of the preset diesel pump 132, so as to control the second working state of the diesel supply module through the second cutoff valve 142. For example, the embodiment of the present invention controls the operating state of the diesel supply module by controlling the opening and closing of the second shut-off valve 142. In addition, the diesel flow meter 122 in the embodiment of the present invention includes a second flow meter input end and a second flow meter output end, and the second flow meter input end is connected to the second shut-off output end of the second shut-off valve 142. Among other things, embodiments of the present invention measure and regulate the diesel output of the diesel tank 112 via the diesel flow meter 122. Further, in an embodiment of the present invention, diesel common rail submodule 152 includes a second common rail input and a second common rail output. The second common rail input end in the embodiment of the present invention is connected to the second flowmeter output end of the diesel flowmeter 122. Accordingly, in the embodiment of the present invention, the diesel output state is controlled and adjusted by the diesel common rail sub-module 152, and the diesel common rail sub-module 152 ensures the stability and accuracy of fuel supply by controlling the working pressure of the preset diesel pump 132, so as to improve the combustion efficiency and performance of the engine. Meanwhile, in the embodiment of the invention, the diesel common rail submodule 152 and the methanol common rail submodule 151 can also realize the mixed control of fuel and air by controlling the injection time and the injection quantity of the oil nozzle according to the working condition and the load requirement of the engine so as to optimize the combustion process, reduce the emission and improve the fuel utilization rate. Further, the preset diesel injector 162 in the present embodiment includes a diesel injection end and a second injector input end. In this embodiment of the present invention, the second injector input end is connected to the second common rail output end of the diesel common rail submodule 152, so as to input the diesel in the diesel common rail submodule 152 into the preset diesel injector, and further inject the diesel into the engine cylinder 170 through the diesel injection end.

Referring to fig. 1, in some embodiments of the present invention, the marine dual direct injection engine system provided by the embodiments of the present invention further includes a turbocharger 180, an exhaust gas air mixer 230, a methanol-to-pyrolysis gas mixer 240, and an intercooler 250. Specifically, the turbocharger 180 in the embodiment of the present invention includes a first air inlet end, a first air outlet end, a second air inlet end, and a second air outlet end. In this embodiment, the turbocharger 180 inputs air through the first air inlet, i.e. obtains air. Accordingly, in the embodiment of the invention, the second air inlet end is connected with the second exhaust gas output pipeline of the exhaust gas recirculation module, so that the turbocharger is driven by the energy of the exhaust gas to rotate and compress the air inlet, thereby increasing the air inlet pressure and density of the engine and improving the efficiency and performance of the engine. Next, in the embodiment of the present invention, the air after being pressurized and compressed is input into the exhaust air mixer 230 through the first air outlet end. The exhaust air mixer 230 in the embodiment of the present invention includes a first mixing input end, a second mixing input end, and a first mixing output end. Accordingly, in the embodiment of the present invention, the first mixing input end is connected to the first air outlet end of the turbocharger 180, and the second mixing input end is connected to the first exhaust gas output pipeline through the exhaust gas circulation valve 222, so as to mix the air obtained by the turbocharger 180 with the cooled exhaust gas through the exhaust gas air mixer 230, so as to obtain a first mixed gas. Next, the first mixed gas is input into the methanol cracking gas mixer 240 through the first mixing output end of the exhaust gas air mixer 230 to be further mixed with the cracked gas. The methanol pyrolysis gas mixer 240 according to the embodiment of the present invention includes a third mixing input end, a fourth mixing input end, and a second mixing output end. Accordingly, in the embodiment of the present invention, the third mixing input is connected to the first mixing output of the exhaust gas air mixer 230, and the fourth mixing input is connected to the cracking output of the methanol cracking module through the cracking gas valve 193, so as to form a cracking gas pipeline 192. According to the embodiment of the invention, the first mixed gas is mixed with the methanol cracking gas through the methanol cracking gas mixer 240 to obtain the target mixed gas, and the target mixed gas is further input into the engine, so that hydrogen-doped combustion is realized, and clean, efficient and controllable combustion in a wide working condition range is realized. In addition, after the target mixed gas is obtained by mixing, the embodiment of the present invention first inputs the target mixed gas into the intercooler 250 to cool the target mixed gas. The intercooler 250 of the embodiment of the present invention includes an intercooler input end and an intercooler output end, wherein the intercooler input end is connected to the second mixing output end of the methanol pyrolysis gas mixer 240, and the intercooler output end is connected to the intake manifold 171 of the engine, so as to introduce the cooled target mixed gas into the engine.

Referring to fig. 2, an embodiment of the present invention provides a control method of a marine dual direct injection engine system, which can realize clean, efficient and controllable combustion of an engine in a wide working condition range, and effectively alleviate the problem of limited operation working conditions. The method of the embodiment of the invention includes, but is not limited to, step S310, step S320 and step S330.

Specifically, the process of applying the method of the embodiment of the invention to the marine dual direct injection engine system includes, but is not limited to, the following steps:

s310: and acquiring preset engine parameters. The preset engine parameters comprise engine speed, expected engine power and rated engine power.

S320: an engine operating mode is determined based on the engine speed, the desired engine power, and the rated engine power.

S330: and controlling the working state of a preset control module according to the working condition mode of the engine so as to adjust the running state of the engine. The preset control module comprises a methanol cracking module, an exhaust gas recirculation module, a methanol supply module and a diesel supply module.

In the embodiment of the invention, the preset engine parameters are firstly obtained to determine the corresponding engine working condition mode according to the preset engine parameters, and then the working state of the preset control module is controlled according to the engine working condition mode, so that the engine combustion mode is adjusted, clean, efficient and controllable combustion in a wide working condition range is realized, and the problem of limited operation working condition is effectively relieved. Specifically, the preset engine parameters in the embodiment of the invention include the engine speed, the expected power of the engine and the rated power of the engine. According to the embodiment of the invention, the working modes of the engine, such as a cold start working mode, a low-load working mode, a medium-load working mode and a high-load working mode, are determined according to the relation among the engine rotating speed, the expected engine power and the rated engine power. Further, according to the embodiment of the invention, the working states of the preset control module, such as the methanol cracking module, the exhaust gas recirculation module, the methanol supply module and the diesel supply module, are correspondingly adjusted according to the determined working condition mode of the engine, so that the adjustment of the running state of the engine, such as the adjustment of the combustion mode of the engine, such as the Methanol Mixed Limited Combustion (MMLC) mode, the methanol homogeneous charge premixed combustion (MHCC) mode, the methanol partial premixed combustion (MPCC) mode and the like, is realized. Specifically, in the process of adjusting the running state of the engine, the embodiment of the invention adjusts the combustion mode of the engine by adjusting the working states of the methanol supply module and the diesel supply module, namely adjusting the injection time sequence of methanol and diesel, and simultaneously assists in regulating and controlling the combustion process of the engine cylinder by adjusting the working states of the methanol cracking module and the exhaust gas recirculation module. It is easy to understand that in the embodiment of the invention, the mode of adjusting the working state of the preset control module can be realized by determining the corresponding working condition mode of the engine according to the preset engine parameters, so that the adjustment and control of the running state of the engine can be realized, clean, efficient and controllable combustion can be realized in a wide working condition range, and the problem of limited running working condition is effectively relieved.

In some embodiments of the present invention, an engine operating mode is determined based on engine speed, desired engine power, and rated engine power, including, but not limited to, the steps of:

and when the engine rotating speed is determined to be zero, determining that the engine working condition mode is a cold start working mode.

Or when the engine speed is determined to be not zero and the expected power of the engine is smaller than or equal to the first threshold value of the rated power of the engine, determining that the engine working condition mode is a low-load working condition mode.

Or when the engine speed is determined to be not zero, the expected power of the engine is larger than a first threshold value, and the expected power of the engine is smaller than or equal to a second threshold value of the rated power of the engine, and the engine working condition mode is determined to be a medium load working condition mode.

Or when the engine speed is determined to be not zero, the expected power of the engine is greater than a second threshold value, and the engine working condition mode is determined to be a high-load working condition mode.

In this specific embodiment, the embodiment of the invention determines the corresponding engine working condition mode through the engine speed and the relationship between the expected power of the engine and the rated power of the engine. Specifically, the embodiment of the invention firstly judges whether the engine speed is zero. When the engine rotating speed is determined to be zero, the engine is considered to be in a cold start state, and the engine is judged to enter a cold start first cycle mode, namely, the working condition mode of the engine is determined to be a cold start working mode. On the contrary, when the engine rotating speed is determined not to be zero, the embodiment of the invention judges the relation between the rated power of the engine and the expected power of the engine so as to further determine the working mode of the engine. Accordingly, when it is determined that the desired engine power is less than the first threshold of the rated engine power, the engine operating mode is determined to be a low load operating mode. For example, when it is determined that the engine speed is not zero and the desired engine power is less than or equal to 40% of the rated engine power, then the engine is determined to be in a low load operating mode. Further, when it is determined that the engine speed is not zero, and at the same time, the expected power of the engine is greater than a first threshold value of the rated power of the engine, and the expected power of the engine is less than or equal to a second threshold value of the rated power of the engine, the embodiment of the invention determines that the engine working condition mode is a medium load working condition mode. For example, when it is determined that the engine speed is not zero and the desired engine power is greater than 40% of the rated engine power and less than or equal to 70% of the rated engine power, i.e., 40% of the rated engine power < 70% of the desired engine power is less than or equal to 70% of the rated engine power, embodiments of the present invention determine that the engine is in the medium load mode of operation, i.e., the medium load mode of operation. Further, when it is determined that the engine speed is not zero and the expected engine power is greater than the second threshold, the embodiment of the invention determines that the engine operating mode is a high load operating mode. For example, when it is determined that the engine speed is not equal to 0 and 70% of the engine rated power is less than or equal to 100% of the engine rated power, embodiments of the present invention determine that the engine is in a high load operating mode, i.e., a high load operating mode. In the embodiment of the present invention, the desired power of the engine refers to the power required by the engine determined by the controller ECU according to the conditions such as the water flow speed, the water flow direction, the sailing direction, and the like.

In some embodiments of the present invention, the operating state of the preset control module is controlled according to the engine operating mode to adjust the engine operating state, including but not limited to the following steps:

when the engine operating mode is determined to be a cold start operating mode, the exhaust gas recirculation module is turned off and the diesel supply module is controlled to output diesel to the engine.

And controlling the methanol supply module to output methanol to the alcohol cracking module so as to carry out a methanol cracking reaction to obtain methanol cracking gas, and inputting the methanol cracking gas into the engine.

In this embodiment, when the engine operating mode is a cold start operating mode, the exhaust gas recirculation module is turned off, and accordingly, the diesel supply module is started to control the diesel supply module to output diesel to the engine, and simultaneously, the methanol supply module and the methanol cracking module are started to control the methanol supply module to output methanol to the methanol cracking module to perform a methanol cracking reaction, so as to obtain methanol cracking gas, and the methanol cracking gas is input into the engine to perform cold start of the engine in a pure diesel mode. In an exemplary embodiment of the present invention, in a cold start first cycle operation, i.e., in a cold start operation mode, in a methanol supply loop, the embodiment of the present invention first opens a methanol tank, and methanol enters a catalyst pipeline via a preset methanol pump, a third stop valve, and a methanol bypass flowmeter. Then, the embodiment of the invention starts the diesel supply module, opens the diesel tank of the diesel supply loop, and enables diesel to enter the engine cylinder through the diesel flowmeter, the preset diesel pump, the second stop valve and the diesel common rail sub-module and the preset diesel injector. In addition, in the air inlet loop of the embodiment of the invention, the filtered air enters the engine cylinder through the air inlet manifold by the turbocharger, the exhaust gas air mixer, the methanol pyrolysis gas mixer and the intercooler. Accordingly, in the exhaust circuit of the embodiment of the invention, the combusted exhaust gas directly enters the turbocharger to be discharged through the exhaust manifold and the methanol cracking reactor.

In some embodiments of the present invention, the operating state of the preset control module is controlled according to the engine operating mode to adjust the engine operating state, and the method further includes, but is not limited to, the following steps:

and when the working condition mode of the engine is determined to be a low-load working condition mode, controlling the methanol cracking module, the diesel oil supply module and the methanol supply module to be started.

Injection timing of the diesel supply module and the methanol supply module is adjusted to control the engine to operate in a methanol mixed limited combustion mode.

And adjusting the first injection parameter, the hydrogen production rate of methanol pyrolysis and the methanol energy ratio according to preset engine parameters. The preset engine parameters comprise engine exhaust temperature and engine load demand, and the first injection parameters comprise methanol injection time and diesel injection time.

And controlling an intake valve of the engine to be opened secondarily according to a preset valve control law so as to perform internal exhaust gas recirculation operation.

In this embodiment, when the engine operating mode is a low-load operating mode, the embodiment of the invention firstly controls the methanol cracking module, the diesel oil supply module and the methanol supply module to be turned on, then adjusts the injection timing of the diesel oil supply module and the methanol supply module to control the engine to work in a Methanol Mixing and Limited Combustion (MMLC) mode, and controls the intake valve of the engine to be turned on according to a preset valve control rule so as to realize the secondary opening of the intake valve, so that part of exhaust gas remains in the cylinder to form internal exhaust gas circulation (EGR). Specifically, referring to fig. 3 and 4, when in the low-load working mode, the embodiment of the invention controls the controller ECU to open the methanol supply module, the diesel supply module and the methanol cracking gas pipeline, i.e. the methanol cracking module, and close the external EGR pipeline, i.e. the exhaust gas recirculation module, and then controls the injection timing of methanol and diesel to realize the Methanol Mixed Limited Combustion (MMLC) mode, as shown in fig. 3. Meanwhile, the embodiment of the invention changes the valve generation rule through the control of the controller ECU so as to enable the intake valve to be opened secondarily, as shown in fig. 4. In the embodiment of the invention, the valve control law, namely the preset valve control law, refers to the law of controlling the opening and closing time, duration and speed of the valve. Then, according to the embodiment of the invention, the first injection parameter, the hydrogen production rate of methanol pyrolysis and the energy proportion of methanol are adjusted according to the preset engine parameters. Specifically, in the embodiment of the invention, the preset engine parameters include an engine exhaust temperature and an engine load demand, and the first injection parameters include a methanol injection time and a diesel injection time. Under the low-load working condition, the methanol injection time, the diesel injection time, the methanol energy proportion and the methanol cracking hydrogen production rate in the embodiment of the invention are all feedback regulated and controlled by the controller ECU according to the exhaust temperature of the engine and the load demand of the engine. Accordingly, in a Methanol Mixed Limited Combustion (MMLC) mode, the embodiment of the invention controls the energy ratio of methanol to a first energy ratio interval, such as the energy ratio of methanol between 50% and 80%, through the controller ECU, with the remaining energy supplied by the pilot diesel. The controller ECU adjusts the power by increasing the sum of the energy of the methanol and the energy of the diesel. It should be noted that, in the embodiment of the present invention, the combustion mode of the engine is controlled by the injection timing, and each load corresponds to one combustion mode. Accordingly, embodiments of the present invention assist in regulating combustion (optimizing in-cylinder combustion processes) by means of methanol cracking and exhaust gas recirculation. Illustratively, in a low load operating mode, embodiments of the present invention turn the methanol cracking module on and turn the EGR line off. The diesel oil supply loop in the embodiment of the invention is consistent with a cold start first circulation mode. In addition, in the methanol supply loop of the embodiment of the invention, the methanol tank is firstly opened, so that a part of methanol enters the engine cylinder through the methanol flowmeter, the preset methanol pump, the first stop valve and the methanol common rail sub-module through the preset methanol injector, and the other part of methanol enters the catalyst pipeline through the third stop valve and the methanol branch flow meter. In the intake circuit of the embodiment of the invention, the filtered air enters the engine cylinder through the air intake manifold by the turbocharger, the exhaust air mixer, the methanol pyrolysis gas mixer and the intercooler. In the exhaust circuit of the embodiment of the invention, the combusted exhaust gas enters the turbocharger to be discharged through the exhaust manifold and the methanol cracking reactor. It should be noted that, in the embodiment of the invention, the waste gas does not participate in the methanol cracking reaction, only the waste heat is used to heat the catalyst in the catalyst pipeline, so as to promote the methanol cracking reaction, and the methanol cracking gas enters the methanol cracking gas mixer to be fully mixed with air after passing through the cracking gas pipeline, namely the cracking output end and the cracking gas valve, and at the moment, the waste gas circulation valve is in a closed state.

when the working condition mode of the engine is determined to be a medium-load working condition mode, the exhaust gas recirculation module, the methanol cracking module, the diesel oil supply module and the methanol supply module are controlled to be started;

injection timing of the diesel supply module and the methanol supply module is adjusted to control the engine to operate in a methanol homogeneous charge premixed combustion mode.

And adjusting the first injection parameter, the hydrogen production rate of methanol pyrolysis, the methanol energy proportion and the exhaust gas recirculation rate according to the preset output parameter. The preset output parameters comprise an engine load demand, knocking output feedback and knocking pressure output feedback, and the first injection parameters comprise methanol injection time and diesel injection time.

In this embodiment, when the engine operating mode is the medium load operating mode, the embodiment of the invention first controls the exhaust gas recirculation module, the methanol cracking module, the diesel supply module and the methanol supply module to be turned on, and then adjusts the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol homogeneous charge premixed combustion (mhc) mode. Specifically, referring to fig. 5, in the embodiment of the present invention, the controller ECU controls the opening of the methanol supply module, the diesel supply module, the external EGR line, and the methanol cracking gas line, that is, the exhaust gas recirculation module and the methanol cracking module, and controls the injection timing of methanol and diesel to implement a methanol homogeneous charge premixed combustion mode (mhc). The embodiment of the invention controls the engine to work in a methanol homogeneous charge premixed combustion (MHCC) mode by adjusting the injection time sequences of the diesel supply module and the methanol supply module, namely controlling the methanol injection time and the diesel injection time. Then, the embodiment of the invention adjusts the first injection parameter, the hydrogen production rate of methanol pyrolysis, the methanol energy ratio and the exhaust gas recirculation rate according to the preset output parameter. Specifically, in the embodiment of the invention, the preset output parameters include an engine load demand, knocking output feedback and detonation pressure output feedback, and the first injection parameters include a methanol injection time and a diesel injection time. Under the medium load working condition, the methanol energy proportion, the diesel injection time, the methanol cracking hydrogen production rate and the external exhaust gas recirculation rate in the embodiment of the invention are all feedback-controlled by the controller ECU according to the engine load requirement, the detonation pressure output feedback and the detonation output feedback. For example, in a methanol homogeneous charge premixed combustion (MHCC) mode, embodiments of the present invention control the energy ratio of methanol to be between 60% -90% by the controller ECU, with the remaining energy supplied by the pilot diesel. Illustratively, in the medium load mode, the methanol cracking module and the exhaust gas recirculation module of the embodiments of the present invention are both on. The air inlet loop and the methanol and diesel oil supply loop are consistent with those in low load. Accordingly, in the exhaust circuit of the embodiment of the invention, the combusted exhaust gas is discharged through an exhaust manifold, a methanol cracking reactor, and into a turbocharger. In addition, part of the exhaust gas passing through the methanol cracking reactor is affected by the pressure difference and enters the exhaust gas air mixer through the exhaust gas recirculation pipeline, namely the first exhaust gas output pipeline and the exhaust gas recirculation valve, and is fully mixed with air. It should be noted that, in the embodiment of the invention, the waste gas does not participate in the methanol cracking reaction, only the waste heat is used to heat the catalyst in the catalyst pipeline, so as to promote the methanol cracking reaction, and the methanol cracking gas enters the methanol cracking gas mixer to be fully mixed with air and waste gas after passing through the cracking gas pipeline, namely the cracking output end and the cracking gas valve.

and when the working condition mode of the engine is determined to be a high-load working condition mode, controlling the exhaust gas recirculation module, the diesel oil supply module and the methanol supply module to be started.

And adjusting injection time sequences of the diesel oil supply module and the methanol supply module to control the engine to work in a methanol partial premixing combustion mode.

And adjusting the second injection parameter and the exhaust gas recirculation rate according to the preset output parameter. The preset output parameters comprise an engine load demand, knocking output feedback and knocking pressure output feedback, and the second injection parameters comprise a primary methanol injection proportion, a secondary methanol injection proportion, a methanol injection moment and a diesel injection moment.

In this embodiment, when the engine operating mode is the high load operating mode, the embodiment of the invention first controls the exhaust gas recirculation module, the diesel supply module and the methanol supply module to be turned on, and controls the engine to operate in the methanol partial premixed combustion (MPCC) mode by adjusting injection timings of the diesel supply module and the methanol supply module. Specifically, referring to fig. 6, in the embodiment of the present invention, the controller ECU controls to open the methanol supply module, the diesel supply module, the external EGR line, i.e., the exhaust gas recirculation module, and close the methanol cracking gas line, i.e., the methanol cracking module, so as to implement the methanol partial premixed combustion Mode (MPCC) by controlling the injection timing of methanol and diesel. For example, the embodiment of the invention controls the energy proportion of the methanol to be 60% -80% through the controller ECU, and the rest energy is supplied by the ignition diesel. The controller ECU adjusts the power by increasing the sum of the energy of the methanol and the energy of the diesel. In addition, the embodiment of the invention adjusts the second injection parameter and the exhaust gas recirculation rate according to the preset output parameter. The preset output parameters comprise knocking output feedback, knocking pressure output feedback and engine load requirements, and the second injection parameters comprise a primary injection proportion of methanol, a secondary injection proportion of methanol, methanol injection time and diesel injection time. In the methanol partial premixed combustion Mode (MPCC), the proportion of primary injection and secondary injection of methanol, the methanol injection time, the diesel injection time and the exhaust gas recirculation rate are all feedback-controlled by the controller ECU according to the load requirement of the engine, the detonation pressure and the detonation output feedback. Illustratively, in a high load operating mode, embodiments of the present invention turn the methanol cracking module off and the exhaust gas recirculation module on. Correspondingly, the air inlet loop and the diesel oil supply loop in the embodiment of the invention are consistent with the low-load and medium-load working condition modes. In the methanol supply loop of the embodiment of the invention, methanol enters an engine cylinder through a methanol flowmeter, a preset methanol pump, a first stop valve and a methanol common rail sub-module and a preset methanol injector. Accordingly, in the exhaust circuit of the embodiment of the invention, the combusted exhaust gas is discharged through an exhaust manifold, a methanol cracking reactor, and into a turbocharger. In addition, part of the exhaust gas passing through the methanol cracking reactor is affected by the pressure difference and enters the exhaust gas air mixer to be fully mixed with air through the EGR pipeline, namely the first exhaust gas pipeline and the exhaust gas circulation valve. At this time, the cracking gas valve is in a closed state.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

While the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the above embodiment, and various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the present invention, and these equivalent modifications and substitutions are intended to be included in the scope of the present invention as defined in the appended claims.

Claims

1. A marine dual direct injection engine system, comprising:

a methanol supply module for providing methanol;

a diesel supply module for providing diesel;

2. The marine dual direct injection engine system of claim 1, wherein the methanol supply module comprises:

a methanol tank for storing and outputting the methanol;

3. The marine dual direct injection engine system of claim 1, wherein the diesel supply module comprises:

chai Youguan said diesel tank for storing and outputting said diesel;

4. The marine dual direct injection engine system of claim 1, further comprising:

5. A control method of a marine dual direct injection engine system, characterized in that the method is applied to the marine dual direct injection engine system of claim 1, comprising:

6. The method of controlling a marine dual direct injection engine system according to claim 5, wherein the determining an engine operating mode based on the engine speed, the desired engine power, and the rated engine power comprises:

7. The control method of the marine dual direct injection engine system according to claim 6, wherein the controlling the operation state of the preset control module according to the engine operating mode to adjust the engine operating state includes:

8. The control method of the marine dual direct injection engine system according to claim 6, wherein the controlling the operation state of the preset control module according to the engine operating mode to adjust the engine operating state further comprises:

9. The control method of the marine dual direct injection engine system according to claim 6, wherein the controlling the operation state of the preset control module according to the engine operating mode to adjust the engine operating state further comprises:

10. The control method of the marine dual direct injection engine system according to claim 6, wherein the controlling the operation state of the preset control module according to the engine operating mode to adjust the engine operating state further comprises: