Servo oil driving device of marine methanol dual-fuel low-speed diesel engine

Abstract

A servo oil driving device of a marine methanol dual-fuel low-speed diesel engine is characterized in that the dual-fuel low-speed diesel engine comprises a crankshaft gear, a methanol pressurizing unit and a host control system, and the servo oil driving device comprises a driving gear, an intermediate gear, a pinion, a servo oil pump, a low-pressure hydraulic oil pipeline and a high-pressure servo oil pipeline; the driving gear, the intermediate gear and the pinion form a gear set which is arranged in the shell, the crankshaft gear is connected with and drives the driving gear, the intermediate gear is coaxially and fixedly connected with the driving gear, the pinion is meshed with the intermediate gear, the servo oil pump is coaxially connected with the pinion, and the low-pressure hydraulic oil pipeline is connected with the servo oil pump. The high-pressure servo oil pipeline is connected to the output end of the servo oil pump; the gear set is driven by a crankshaft gear to drive a servo oil pump to pressurize low-pressure hydraulic oil to servo oil with set working pressure, and finally methanol is driven to be pressurized to achieve methanol injection. The crankshaft gear is used for replacing an electric pump to drive the servo oil system, and has the advantages of being simple in structure, good in economical efficiency, high in safety, capable of saving energy, environmentally friendly, good in universality and the like.

Description

Technical Field

[0001] The present invention relates to a marine methanol dual - fuel low - speed diesel engine, and particularly to a servo - oil drive device for a marine methanol dual - fuel low - speed diesel engine, belonging to the technical field of marine low - speed diesel engines. Background Technique

[0002] With the popularization of dual - fuel applications in the field of marine low - speed diesel engines and the continuous exploration of low - carbon fuels for the shipping industry globally, methanol, as a green fuel, has gradually emerged and is being adopted by more and more ships. Methanol, also known as methyl alcohol, has the chemical formula CH3OH. It contains no sulfur in its composition, has a high oxygen content, and a low combustion temperature. Compared with conventional diesel, there are no sulfides in the emissions after methanol combustion, and the emissions of solid particles, nitrogen oxides, and carbon dioxide can be reduced by 90%, 30%, and 10% respectively. It is a green and clean energy source. However, methanol is also a flammable and toxic liquid. As a fuel for ship engines, how to ensure its safe and stable entry into the cylinder for combustion is crucial for the normal operation of the engine and the safety of the ship.

[0003] During the normal operation of a methanol dual - fuel diesel engine, methanol is transported to the dual - fuel low - speed diesel engine through a supply pipeline. The methanol supply pressure is generally about 13 bar, that is, a pressure sufficient to effectively prevent methanol vaporization is required. An excessively high supply pressure means an increased risk of leakage. However, the pressure for injecting liquid methanol into the cylinder needs to reach about 600 bar for effective atomization and sufficient combustion to ensure the stable operation of the methanol dual - fuel diesel engine. Therefore, before methanol enters the cylinder, it needs to be further pressurized to reach a 600 - bar injection pressure.

[0004] As a toxic and dangerous substance, methanol cannot be directly pressurized by an electric pump in the engine room. Therefore, a scheme of driving a servo - oil system by an electric pump and then pressurizing is generally adopted, that is, first pressurize the servo - oil by an electric pump, and then the servo - oil system drives a methanol pressurizing device to pressurize methanol to a 600 - bar injection pressure and inject it into the cylinder.

[0005] The scheme of driving a servo - oil system by an electric pump has a simple principle, and the electric - pump - driven servo - oil system is independent of the existing diesel - engine servo - oil system, without mutual influence and with flexible layout.

[0006] However, the scheme of driving a servo - oil system by an electric pump has the following drawbacks:

[0007] 1) The system needs to consume additional electricity on the ship, and the power consumption is large. Since methanol has a low calorific value, in the methanol mode, for the diesel engine to achieve the same power as in the diesel mode, the injection amount of methanol is more than twice that of diesel. A larger injection amount means that more servo - oil is needed to drive the pressurization of methanol, resulting in huge power consumption.

[0008] 2) The high-pressure pipeline is long, and the risk of methanol leakage is high. Due to the large demand for servo oil, the volume of the electric pump device increases, so it cannot be arranged on the diesel engine body and can only be arranged in the engine room area, resulting in a relatively long high-pressure methanol pipeline and increasing the leakage risk.

[0009] 3) Additional electrical equipment such as electrical control boxes is added, increasing the risk of equipment failure.

[0010] 4) The initial investment cost and operating cost of the equipment are relatively high. Summary of the Invention

[0011] The purpose of the present invention is to overcome the drawbacks of the existing servo oil drive system scheme with an electric pump, and provide a servo oil drive device for a marine methanol dual-fuel low-speed diesel engine. The servo oil pump is driven by the existing crankshaft gear of the low-speed diesel engine to replace the electric pump to pressurize the low-pressure hydraulic oil to servo oil with a set working pressure, and then finally drive the methanol pressurization through the servo oil to achieve methanol injection, so as to achieve the effects of reducing energy consumption, reducing the pipeline leakage risk, and reducing the equipment cost.

[0012] To achieve the above purpose, the technical solution of the present invention is as follows:

[0013] A servo oil drive device for a marine methanol dual-fuel low-speed diesel engine, the dual-fuel low-speed diesel engine includes a crankshaft gear, a methanol pressurization unit, and a main engine control system; characterized in that: the servo oil drive device includes a drive gear, an intermediate gear, a pinion gear, a servo oil pump, a low-pressure hydraulic oil pipeline, and a high-pressure servo oil pipeline;

[0014] The drive gear, the intermediate gear, and the pinion gear form a gear set and are installed within a housing. The drive gear is connected to and driven by the crankshaft gear. The intermediate gear is coaxially and fixedly connected to the drive gear. The pinion gear meshes with the intermediate gear. The servo oil pump is coaxially connected to the pinion gear. The low-pressure hydraulic oil pipeline is connected to the servo oil pump for providing hydraulic oil and lubrication. The high-pressure servo oil pipeline is connected to the output end of the servo oil pump for delivering the pressurized servo oil to the methanol pressurization unit;

[0015] The gear set is driven by the crankshaft gear to drive the servo oil pump to work, pressurize the low-pressure hydraulic oil to servo oil with a set working pressure, and finally drive the methanol pressurization to achieve methanol injection.

[0016] Furthermore, a pressure sensor is provided on the low-pressure hydraulic oil pipeline, and a flow sensor is provided at the connection with the servo oil pump. The flow sensor and the pressure sensor are connected to the host control system, and the detection signals are fed back to the host control system to monitor and adjust the servo oil pressure and flow rate to meet the different requirements for servo oil flow rate under different powers.

[0017] Furthermore, the pinion gear is connected to the servo oil pump through an anti-overload coupling to prevent the overload damage of the servo oil pump.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] a. Simple structure - The driving device gear set is driven by the crankshaft gear, without complex structural components.

[0020] b. High safety - The driving device is installed inside the overall housing, without exposed rotating parts, ensuring the personal safety of the crew during operation.

[0021] c. High reliability - The driving device is mainly composed of mechanical structures such as gear sets, with mature technology and high reliability.

[0022] d. Good economy - It is directly driven by the crankshaft gear of the diesel engine itself, without additional power input, saving the energy consumption on the ship, and being energy-saving and environment-friendly.

[0023] e. Good integration - The driving device is integrated at the position of the diesel engine seat, occupying a small space and being convenient for maintenance.

[0024] f. Good versatility - It can be applied to various dual-fuel low-speed diesel engines such as LNG, LPG, and ammonia only by appropriately adjusting the selection of the gear set and the servo oil pump.

[0025] In summary, the present invention uses the crankshaft gear to replace the electric pump to drive the servo oil system, and has the advantages of simple structure, high safety, high reliability, good economy, energy-saving and environment-friendly, good integration, convenient maintenance, and good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the present invention.

[0027] Figure 2 is an installation schematic diagram of the anti-overload coupling.

[0028] In the figure,

[0029] 1 - Driving gear, 2 - Intermediate gear, 3 - First pinion gear, 4 - Second pinion gear, 5 - First servo oil pump, 6 - Second servo oil pump, 7 - Third servo oil pump, 8 - Fourth servo oil pump, 9 - First flow sensor, 10 - Second flow sensor, 11 - Third flow sensor, 12 - Fourth flow sensor, 13 - Pressure sensor, 14 - Low-pressure servo oil pipeline, 15 - Housing, 16 - First high-pressure servo oil pipeline, 17 - Second high-pressure servo oil pipeline, 18 - Third high-pressure servo oil pipeline, 19 - Fourth high-pressure servo oil pipeline, 20 - Anti-overload coupling. Detailed implementation manner

[0030] The following further elaborates in detail on the servo oil drive device of the marine methanol dual-fuel low-speed diesel engine according to the present invention in combination with the accompanying drawings and specific embodiments.

[0031] The present invention is used for the servo oil drive of a marine methanol dual-fuel low-speed diesel engine. The dual-fuel low-speed diesel engine includes a crankshaft gear, a methanol pressurization unit, and a main engine control system.

[0032] Embodiment

[0033] Please refer to Figure 1 , the servo oil drive device includes a driving gear 1, an intermediate gear 2, a first pinion gear 3, a second pinion gear 4, a first servo oil pump 5, a second servo oil pump 6, a third servo oil pump 7, a fourth servo oil pump 8, a low-pressure hydraulic oil pipeline 14, a first high-pressure servo oil pipeline 16, a second high-pressure servo oil pipeline 17, a third high-pressure servo oil pipeline 18, and a fourth high-pressure servo oil pipeline 19.

[0034] The driving gear 1, the intermediate gear 2, the first pinion gear 3, and the second pinion gear 4 form a gear set and are installed within the housing 15. The lubricating oil within the housing 15 ensures the effective lubrication of the gear set. The driving gear 1 is connected to the crankshaft gear and is driven by the crankshaft gear. The intermediate gear 2 is coaxially and fixedly connected to the driving gear 1. The first pinion gear 3 and the second pinion gear 4 are respectively meshed with the intermediate gear 2 from both sides. The gear set is used to transmit the rotation of the crankshaft to the servo oil pump and drive the servo oil pump to rotate. The rotation speed transmitted by the intermediate gear 2 is designed according to a certain ratio to meet the rated rotation speed of the servo oil pump and achieve the effective transmission of the rotation speed and driving torque.

[0035] The first servo oil pump 5 and the third servo oil pump 7 are coaxially connected to both sides of the first pinion gear 3, and the second servo oil pump 6 and the fourth servo oil pump 8 are coaxially connected to both sides of the second pinion gear 4.

[0036] The low-pressure hydraulic oil pipeline 14 is respectively connected to the first servo oil pump 5, the second servo oil pump 6, the third servo oil pump 7 and the fourth servo oil pump 8. The low-pressure hydraulic oil pipeline 14 is used to supply hydraulic oil to all servo oil pumps and is also used for lubricating the servo oil pumps, the gear set, etc. At the output ends of the first servo oil pump 5, the second servo oil pump 6, the third servo oil pump 7 and the fourth servo oil pump 8, a first high-pressure servo oil pipeline 16, a second high-pressure servo oil pipeline 17, a third high-pressure servo oil pipeline 18 and a fourth high-pressure servo oil pipeline 19 are respectively connected, which are used to transport the high-pressure servo oil pressurized by the servo oil pumps to the methanol pressurizing unit to drive methanol pressurization.

[0037] At the connection points of the first servo oil pump 5, the second servo oil pump 6, the third servo oil pump 7 and the fourth servo oil pump 8 with the low-pressure hydraulic oil pipeline 14, a first flow sensor 9, a second flow sensor 10, a third flow sensor 11 and a fourth flow sensor 12 are respectively arranged. A pressure sensor 13 is arranged on the low-pressure hydraulic oil pipeline 14. The first flow sensor 9, the second flow sensor 10, the third flow sensor 11, the fourth flow sensor 12 and the pressure sensor 13 are connected to the host control system and are used to monitor the pressure and flow of the servo oil. The first flow sensor 9, the second flow sensor 10, the third flow sensor 11, the fourth flow sensor 12 and the pressure sensor 13 feedback the detection signals to the host control system to realize the monitoring and adjustment of the pressure and flow of the servo oil, so as to meet the different requirements for the flow of the servo oil under different powers.

[0038] Please refer to Figure 2 , at the connection points of the first pinion gear 3 with the first servo oil pump 5 and the third servo oil pump 7, overload protection couplings 20 are respectively arranged. When an unexpected situation of the servo oil pump being stuck occurs, the overload protection couplings 20 will disengage due to overload, thereby effectively preventing the damage of the servo oil pump. Similarly, the second pinion gear 4 is coaxially connected to the second servo oil pump 6 and the fourth servo oil pump 8 respectively through the overload protection couplings 20.

[0039] The servo oil driving device of the present invention is driven by the diesel engine crankshaft gear, drives the servo oil pump to work, pressurizes the low-pressure hydraulic oil to servo oil with a set working pressure (600 bar), and finally drives methanol pressurization through the servo oil to realize methanol injection.

[0040] The present invention has the advantages of simple structure, high safety, high reliability, good economy, energy conservation and environmental protection, good integration, good versatility, etc.

[0041] ​

Claims

1. A servo oil drive device for a marine methanol dual-fuel low-speed diesel engine, the dual-fuel low-speed diesel engine comprising a crankshaft gear, a methanol pressurizing unit and a main engine control system; characterized in that: The servo oil drive device includes a drive gear, an intermediate gear, a pinion gear, a servo oil pump, a low-pressure hydraulic oil pipeline, and a high-pressure servo oil pipeline; The drive gear, intermediate gear, and pinion gear form a gear set and are installed within a housing. The drive gear is connected to the crankshaft gear and driven by the crankshaft gear. The intermediate gear is coaxially and fixedly connected to the drive gear. The pinion gear meshes with the intermediate gear. The servo oil pump is coaxially connected to the pinion gear. The low-pressure hydraulic oil pipeline is connected to the servo oil pump for providing hydraulic oil and lubrication. The high-pressure servo oil pipeline is connected to the output end of the servo oil pump for delivering the pressurized servo oil to the methanol pressurization unit; The gear set is driven by the crankshaft gear, drives the servo oil pump to work, pressurizes the low-pressure hydraulic oil to servo oil at a set working pressure, and finally drives methanol pressurization to achieve methanol injection.

2. The servo oil drive device of the marine methanol dual-fuel low-speed diesel engine according to claim 1, characterized in that: A pressure sensor is provided on the low-pressure hydraulic oil pipeline, and a flow sensor is provided at the connection with the servo oil pump. The flow sensor and the pressure sensor are connected to the host control system, and feedback the detection signals to the host control system to realize the monitoring and adjustment of the servo oil pressure and flow rate to meet different requirements for the servo oil flow rate under different powers.

3. The servo oil drive device of the marine methanol dual-fuel low-speed diesel engine according to claim 1, characterized in that: The pinion gear is connected to the servo oil pump through an anti-overload coupling to prevent overload damage to the servo oil pump.

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