An intake pipe with methanol injection hole offset

Abstract

The application discloses a kind of methanol injection hole biasing intake pipe, belong to methanol engine intake system technical field, including intake manifold, several intake manifold communication with intake manifold, the arc-shaped flow passage outer wall of each manifold is equipped with recessed injector installation plane, which is provided with methanol injection hole, and the hole is used to install methanol injector in matching;The center axis of methanol injection hole is the injection axis of methanol injector, in the horizontal plane of engine conventional installation state, relative to the flow passage center axis of corresponding intake manifold at injection hole installation position, it is biased to the rear end of engine in parallel: the boundary oil beam of methanol injector injection close to the side of engine front end and the design angle between the inner side wall of the side intake manifold is 20 °;The biasing of injection axis cooperates with the design angle of 20 °, so that the proportion of methanol fuel injected and contacted with the inner side wall of intake manifold does not exceed 20%.The application effectively inhibits fuel wall hanging, improves atomization uniformity.

Description

Technical Field

[0001] This invention relates to the field of methanol engine intake system technology, and in particular to an intake pipe with offset methanol nozzles. Background Technology

[0002] Against the backdrop of green and low-carbon development, methanol, as a widely available, renewable, and clean-burning low-carbon fuel, has become a highly promising alternative fuel for internal combustion engines due to its high octane rating and excellent anti-knock properties. Its industrial application in commercial vehicles, construction machinery, and marine power is accelerating. However, methanol fuel has inherent limitations. Its latent heat of vaporization is approximately 3.2 times that of conventional gasoline, and its atomization and evaporation at low temperatures are significantly more difficult than traditional fossil fuels. When using manifold injection, methanol fuel easily forms a stable oil film on the manifold wall, leading to problems such as engine oil dilution, cold-start misfires, and poor air-fuel mixture uniformity. Ultimately, this results in deteriorated engine combustion, reduced power and fuel economy, and excessive emissions of harmful substances, becoming a core industry pain point restricting the improvement of methanol engine performance and its large-scale promotion.

[0003] To address the common problem of methanol fuel intake manifold wall adhesion, existing technologies often employ solutions such as electrically heated assisted atomization, adding a fuel premixing chamber, and optimizing the injection advance angle. However, these solutions all have significant limitations: the electrically heated solution increases engine energy consumption and the complexity of the electronic control system, and is prone to component failure under long-term high-temperature conditions, resulting in insufficient reliability; the solution of adding a premixing chamber requires significant modifications to the main structure of the intake system, leading to high modification costs, poor platform adaptability, and additional intake resistance, affecting engine charge efficiency; solutions that only optimize injection parameters can only improve atomization under specific operating conditions and cannot achieve anti-wall adhesion control under all operating conditions, failing to fundamentally solve the problem of methanol fuel manifold wall adhesion and failing to balance anti-wall adhesion effect, structural versatility, and operational reliability.

[0004] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0005] The purpose of this invention is to propose an intake pipe with offset methanol nozzles to solve the technical problems of methanol fuel manifold injection being prone to wall adhesion, poor atomization effect, and existing anti-wall adhesion solutions having complex structures and insufficient adaptability to all operating conditions.

[0006] Therefore, the present invention proposes an intake pipe with offset methanol nozzle.

[0007] Preferably, the present invention may also have the following technical features:

[0008] A methanol injection nozzle offset intake pipe includes an intake manifold and a plurality of intake manifolds communicating with the intake manifold. Each intake manifold has a mounting flange at its end for mating with an engine cylinder head.

[0009] Each intake manifold has a concave injector mounting surface on the outer wall of its arc-shaped flow channel. A methanol injection hole is provided on the concave injector mounting surface, and the methanol injection hole is used to install a methanol injector.

[0010] The central axis of the methanol injection hole is the injection axis of the methanol injector. The injection axis is offset parallel to the rear end of the engine in the horizontal plane of the engine's normal installation state, relative to the flow channel central axis of the corresponding intake manifold at the injection hole installation position.

[0011] The design angle between the boundary oil jet near the engine front end and the inner wall of the intake manifold on that side is 20°, which is used to control the amount of contact between the oil jet on that side and the inner wall of the intake manifold on that side.

[0012] The offset arrangement of the injection axis is matched with the 20° design angle so that the proportion of the injected methanol fuel that contacts the inner wall of the intake manifold does not exceed 20%.

[0013] Preferably, the intake manifold includes an upstream curved flow channel section connected to the main intake pipe and a downstream outlet straight section rigidly connected to the mounting flange, wherein the upstream curved flow channel section and the downstream outlet straight section are smoothly connected; the recessed injector mounting plane is disposed on the outer wall of the downstream outlet straight section.

[0014] Preferably, the central axis of the methanol injection orifice is not offset in the radial height direction relative to the central axis of the flow channel of the downstream outlet straight section.

[0015] Preferably, the projection of the injection axis onto the radial section of the downstream outlet straight section falls within the high-speed mainstream airflow region of the downstream outlet straight section; the high-speed mainstream airflow region is the central flow channel region within the downstream outlet straight section where the airflow velocity is not less than 1.2 times the average airflow velocity within the downstream outlet straight section flow channel.

[0016] Preferably, the vertical distance by which the injection axis is offset parallel to the center axis of the flow channel of the corresponding downstream outlet straight section is 1 / 10 to 1 / 3 of the width of the flow channel of the downstream outlet straight section, and the offset distance is determined by fluid simulation optimization.

[0017] Preferably, the mounting flange is a flange structure with a radial dimension larger than that of a conventional intake manifold flange of the same model. On the end face of the mounting flange that mates with the engine cylinder head, there are two independent annular sealing grooves. The two annular sealing grooves are respectively the first sealing groove corresponding to the intake medium and the second sealing groove corresponding to the coolant.

[0018] Preferably, the second sealing groove is disposed along the circumference of the mounting flange, at least partially surrounding the radial outer periphery of the first sealing groove.

[0019] Preferably, the first sealing groove and the second sealing groove form an intersection and connection area at at least one position in the circumferential direction through a shared groove wall. The shared groove wall in the intersection and connection area is a solid wall integrally formed with the mounting flange. The shared groove wall completely isolates the internal cavities of the first sealing groove and the second sealing groove, and they are not connected to each other.

[0020] Preferably, the second sealing groove is used to connect and seal with the cooling water jacket of the engine cylinder head, so that the mounting flange and the cylinder head cooling water jacket form direct heat conduction to indirectly heat the downstream outlet straight section.

[0021] Preferably, the inner wall of the intake manifold is provided with at least one streamlined guide rib extending along the airflow direction inside the intake manifold, and the protrusion height of the guide rib is 1 / 20 to 1 / 10 of the inner diameter of the intake manifold flow channel.

[0022] The beneficial effects of this invention compared to the prior art include:

[0023] 1. This invention solves the problem of methanol fuel adhering to the intake manifold wall from the root. By offsetting the injection axis parallel to the rear end of the engine in the horizontal plane of the engine in the normal installation state, and cooperating with the 20° front boundary oil jet design angle, the contact ratio between methanol fuel and the inner wall of the manifold is stably controlled to not exceed 20% under all operating conditions, avoiding the formation of a stable oil film and effectively solving the problems of oil dilution and abnormal engine wear caused by adhering to the wall.

[0024] 2. Compared to existing technologies that are prone to atomization breakup failures, this invention significantly improves the methanol fuel atomization effect and air-fuel mixture uniformity. By designing an injection axis that is parallel and offset towards the rear end of the engine cylinder head, the methanol fuel jet is directed directly towards the cylinder head intake port, greatly shortening the jet's flight distance and reducing its diffusion time within the manifold. This fundamentally reduces the probability of the jet hitting the walls, avoiding atomization breakup failures caused by jet hitting the walls, significantly improving the mixing uniformity of methanol and air, and optimizing engine combustion efficiency.

[0025] 3. Compared with existing technologies that have poor cold start adaptability, this invention significantly improves the cold start performance of methanol engines. By strictly controlling the fuel collision rate to no more than 20%, the vast majority of methanol fuel is allowed to directly enter the cylinder with the intake airflow, avoiding fuel condensation and adhesion on the cold manifold wall. At the same time, it shortens the fuel jet flight distance, allowing more time for fuel atomization and evaporation in the cylinder, effectively reducing the cold start misfire rate and broadening the low-temperature environment applicability of methanol engines.

[0026] 4. Compared with existing technologies that are prone to exceeding emission standards, this invention effectively reduces harmful emissions from the engine, significantly reduces the generation of unburned methanol, HC and other harmful substances, avoids fluctuations in air-fuel mixture concentration caused by the mass shedding of oil film from the manifold wall, stabilizes and reduces harmful emissions from exhaust gas, and better meets the requirements of China VI and more stringent emission regulations.

[0027] 5. Compared with existing technologies with complex structures and high modification costs, the present invention has strong structural versatility and high long-term reliability. It does not require major modifications to the main structure of the engine intake system or the electronic control system. The core effect can be achieved simply by optimizing the position and angle of the injection holes. At the same time, it is compatible with optimized structures such as flange integrated heating and intake manifold diversion. The platform has wide adaptability, low modification cost, no additional vulnerable components, and excellent working stability. Attached Figure Description

[0028] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 1 .

[0029] Figure 2 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 2 .

[0030] Figure 3 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 3 .

[0031] Figure 4 This is a cross-sectional view of a specific embodiment of the present invention. Figure 1 .

[0032] Figure 5 This is a cross-sectional view of a specific embodiment of the present invention. Figure 2 .

[0033] Explanation of reference numerals in the attached drawings: 1-Intake main pipe; 2-Intake manifold; 21-Mounting flange; 22-Inner recessed injector mounting plane; 23-Methanol injection hole; 24-Upstream curved flow channel section; 25-Downstream outlet straight section; 26-First sealing groove; 27-Second sealing groove; 3-Methanol injector; 4-Fuel jet. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope or application of the present invention.

[0035] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0036] To ensure the clarity and unambiguity of the technical solution described in this embodiment, the core terms involved in the text are given the following unique and explicit definitions, which completely correspond to the meanings of the terms in the claims:

[0037] Engine front / rear end: The engine front end in this invention refers to the timing belt pulley end of the engine; the engine rear end refers to the connection end between the engine flywheel and the gearbox. This is a commonly used spatial reference definition in the industry and is not affected by the engine installation posture.

[0038] Parallel offset: The parallel offset described in this invention refers to two straight lines that are parallel to each other, with the injection axis and the reference flow channel center axis being offset by the vertical distance between the two straight lines in the horizontal plane of the engine in its normal installation state.

[0039] Radial height direction: The radial height direction of the flow channel center axis described in this invention refers to the vertical height direction in the radial section perpendicular to the corresponding flow channel center axis, under the conventional installation state of the engine. Regardless of whether the corresponding flow channel is horizontally arranged, tilted upward or downward, this reference is unique and measurable.

[0040] Design angle: The design angle mentioned in this invention refers to the design reference angle of the methanol injection system. The reasonable tolerance range of ±1° caused by fluctuations in engine operating conditions, changes in intake pressure, and fluctuations in fuel pressure during the actual injection process all fall within the protection scope of this invention.

[0041] Upstream curved flow channel section / downstream straight outlet section: The upstream curved flow channel section mentioned in this invention refers to the curved flow channel section in the intake manifold that is connected to the main intake pipe and is responsible for airflow steering and airflow distribution to each cylinder; the downstream straight outlet section refers to the straight flow channel section in the intake manifold that is rigidly connected to the mounting flange, is responsible for airflow stabilization and connects to the engine cylinder head intake passage. The upstream curved flow channel section and the downstream straight outlet section are smoothly connected without any stepped structure caused by abrupt changes in airflow.

[0042] High-speed mainstream airflow zone: The high-speed mainstream airflow zone mentioned in this invention refers to the central flow channel region within the downstream outlet straight section where the airflow velocity is not less than 1.2 times the average airflow velocity within the downstream outlet straight section flow channel. This is the flow channel section within the internal combustion engine intake manifold where the airflow is most stable and has the strongest entrainment capacity.

[0043] This embodiment provides an intake pipe with offset methanol nozzles, such as... Figures 1-5 As shown, it includes an intake manifold 1 and several intake manifolds 2 connected to the intake manifold 1. Each intake manifold 2 has a mounting flange 21 at its end for docking with the engine cylinder head. Its core improved structure is as follows:

[0044] Each intake manifold 2 has a concave injector mounting surface 22 on the outer wall of its arc-shaped flow channel. The concave injector mounting surface 22 is provided with a methanol injection hole 23, which is used to install a methanol injector 3.

[0045] The central axis of the methanol injection hole 23 is the injection axis of the methanol injector 3, and the injection axis L1 (e.g.) Figure 4 (As shown) In the horizontal plane of the engine in its normal installation state, it is offset parallel to the rear end of the engine relative to the flow channel center axis L2 of the corresponding intake manifold 2 at the methanol injection hole 23 installation position.

[0046] In the oil jet 4 formed by the methanol injector 3, the design angle α between the boundary oil jet near the front end of the engine and the inner wall of the intake manifold 2 on that side is 20°, which is used to control the amount of contact between the oil jet on that side and the inner wall of the intake manifold 2 on that side.

[0047] The offset arrangement of the injection axis L1 is matched with the design angle of 20° so that the proportion of the injected methanol fuel that contacts the inner wall of the intake manifold 2 does not exceed 20%.

[0048] Addressing common industry pain points such as methanol fuel's latent heat of vaporization being approximately 3.2 times that of gasoline, its difficulty in atomization at low temperatures, and its tendency to form a stable oil film on the inner wall of the intake manifold 2, leading to engine oil dilution, cold start misfires, reduced power, and excessive emissions, this solution addresses the root cause of methanol fuel's tendency to adhere to the intake manifold wall through a synergistic design of a parallel offset at the rear end of the injection axis L1 and a 20° angle between the fuel jet at the front side boundary. The aforementioned intake manifold wall-blocking effect is significant, preventing the formation of harmful oil films. CFD fluid simulation and engine bench testing have verified that this solution consistently maintains a contact ratio between methanol fuel and the inner wall of the intake manifold 2 at 12%~18% across all operating conditions (idle, partial load, and full load), preventing the formation of a stable oil film that cannot be carried away by the airflow. This fundamentally solves the oil dilution problem caused by methanol fuel adhering to the intake manifold wall, significantly extending the engine oil change interval and overall engine lifespan. Furthermore, it improves fuel atomization, optimizes combustion performance, and enhances the combustion efficiency of the engine. The offset injection axis L1 design at the rear end of the cylinder head allows the methanol fuel jet to directly target the intake manifold inlet, significantly shortening the jet's flight distance and reducing its diffusion time within the intake manifold 2. This fundamentally reduces the probability of the jet hitting the intake walls, preventing atomization and breakage failures caused by such impacts. It also significantly improves the uniformity of the methanol fuel-intake air mixture, resulting in more complete combustion and effectively enhancing engine power and fuel economy. Bench tests have verified that this can increase engine rated power by 3%~5% and reduce methanol fuel consumption by 4%~6%. This solution significantly improves engine cold start performance. Under cold start conditions, the engine block temperature is low and the intake airflow speed is slow, making methanol fuel atomization exponentially more difficult and prone to misfires due to fuel sticking to the cylinder walls. This solution controls the fuel wall contact rate to no more than 20%, allowing the vast majority of methanol fuel to directly enter the cylinder with the intake airflow. This avoids fuel condensation and adhesion on the cold intake manifold 2 wall, while shortening the fuel jet flight distance, giving the fuel more time to atomize and evaporate in the cylinder. This effectively reduces the engine's cold start misfire rate and can lower the minimum cold start temperature of the methanol engine by 5-8°C, greatly improving its adaptability to low-temperature environments. Furthermore, it reduces harmful emissions, meeting stricter emission regulations. This solution significantly reduces the generation of unburned methanol, avoiding the problem of excessively rich air-fuel mixture caused by the mass shedding of the oil film on the intake manifold 2 wall during sudden changes in engine operating conditions. This effectively reduces HC, CO, and unburned methanol emissions in the engine exhaust. Bench tests have verified that it can reduce unburned methanol emissions by more than 30% and HC emissions by more than 25%, better meeting the requirements of China VI and even stricter emission regulations. This solution does not require any modification to the main structure of the engine cylinder head or intake manifold 1. It only requires optimizing the position and injection angle of the injection port 23 of the intake manifold 2 to directly adapt to existing conventional methanol engine platforms. It has low modification costs, strong versatility, and can quickly achieve mass industrial application.The core improvements in this solution are all optimizations of the mechanical structure, without complex changes to the electrical control system or moving parts. The recessed injector mounting plane 22 and methanol injection hole 23 can be achieved through conventional die casting and milling processes, ensuring machining accuracy, high yield in mass production, no risk of failure under long-term use, and high reliability.

[0049] In some examples of this embodiment, the flow channel structure of the intake manifold 2 and the installation position of the methanol injector 3 are further refined, such as... Figure 1 , 4 As shown in Figure 5, the intake manifold 2 includes an upstream curved flow channel section 24 connected to the intake main pipe 1, and a downstream outlet straight section 25 rigidly connected to the mounting flange 21. The upstream curved flow channel section 24 and the downstream outlet straight section 25 are smoothly connected. The recessed injector mounting plane 22 is disposed on the outer wall of the downstream outlet straight section 25. By placing the recessed injector mounting plane 22 in the downstream outlet straight section 25 near the cylinder head, compared with placing it in the upstream curved flow channel section 24, the flight distance of the methanol fuel jet can be shortened by more than 40%, which significantly reduces the diffusion time of the fuel jet in the intake manifold 2. This further reduces the probability of the fuel jet hitting the wall in space, forming a triple anti-wall synergy effect with the offset design and included angle design of the core solution. The downstream outlet straight section 25 is a stable flow zone, with a much lower turbulence intensity than the upstream curved flow channel section 24. Placing the methanol injector 3 in this area avoids interference from the directional vortices within the upstream curved flow channel 24 on the shape of the methanol jet 4, resulting in a more stable jet 4 shape. The 20° design angle can be stably achieved under all operating conditions, further ensuring the control effect of fuel wall collision rate. The recessed injector mounting plane 22 is located on the outer wall of the downstream outlet straight section 25, in the outer area of ​​the engine compartment. Compared to the upstream curved flow channel section 24, this provides more space for the methanol injector 3 to be installed and removed. The methanol injector 3 can be inspected and replaced without disassembling the intake manifold 1 and other surrounding components, significantly reducing the difficulty and cost of subsequent engine maintenance. The upstream curved flow channel section 24 and the downstream straight outlet section 25 are smoothly connected without steps or abrupt changes, which can effectively reduce the local resistance of the intake airflow. At the same time, the injector mounting plane is a concave structure, which will not bulge into the flow channel to form a throttling effect, ensuring the flow efficiency of the intake manifold 2, improving the engine's intake volume coefficient, and further enhancing the engine's power performance.

[0050] In a further example of this embodiment, such as Figure 1 , 3As shown in Figures 4 and 5, based on the aforementioned flow channel structure, the height of the methanol injection hole 23 is further defined. The central axis L1 (i.e., the injection axis L1) of the methanol injection hole 23 is not offset in the radial height direction relative to the central axis L3 of the downstream outlet straight section 25. The radial height direction referred to here is the vertical height direction within the radial section perpendicular to the central axis L3 of the downstream outlet straight section 25 in the engine's conventional installation state. Regardless of whether the downstream outlet straight section 25 is horizontally arranged, tilted upwards, or tilted downwards, this limitation ensures that the central axis of the methanol injection hole 23 is completely aligned with the central axis of the flow channel in the vertical height direction. This allows the methanol jet to always be injected along the core central area of ​​the flow channel, completely avoiding the risk of contact between the jet and the upper and lower walls of the flow channel from a vertical height perspective. This, combined with the radial offset design of the core scheme, forms a two-dimensional anti-collision control system (radial and height), further stabilizing the technical effect of achieving a fuel collision rate of no more than 20%. The methanol injection orifice 23's central axis is highly aligned with the flow channel's central axis, allowing the methanol jet to precisely target the central area of ​​the downstream cylinder head intake port. This avoids the uneven fuel distribution caused by jet 4's misalignment, enabling more uniform mixing of methanol fuel and intake air before they enter the cylinder. This further optimizes engine combustion stability and reduces cycle variability. Bench tests have verified that the engine cycle variability can be controlled within 3%, significantly improving engine operating stability. The highly aligned design places jet 4 in the central area of ​​the flow channel where airflow velocity is most uniform, avoiding the dragging and deflection effects of low-speed airflow near the flow channel wall on jet 4. This ensures that the diffusion pattern of jet 4 remains highly consistent under all engine operating conditions, preventing jet sinking at low speeds and jet floating upwards at high speeds, further guaranteeing anti-wall-collision performance under all operating conditions.

[0051] In some other examples of this embodiment, the offset distance of the injection axis is further optimized and limited. The vertical distance by which the injection axis is offset parallel to the flow channel center axis of the corresponding downstream outlet straight section 25 is 1 / 10 to 1 / 3 of the width of the downstream outlet straight section flow channel 25. The offset distance is determined by fluid simulation optimization. Extensive fluid simulation and bench testing have verified that when the offset distance is less than 1 / 10 of the flow channel width, the offset is insufficient, resulting in a small safety clearance between the front-side oil jet 4 and the front side wall of the intake manifold 2. This can easily lead to the front-side oil jet 4 hitting the wall when engine operating conditions fluctuate. When the offset distance is greater than 1 / 3 of the flow channel width, excessive offset can cause the rear-side oil jet 4 to be too close to the rear side wall of the intake manifold 2, which can also easily lead to the rear-side oil jet 4 hitting the wall. The offset distance range of 1 / 10 to 1 / 3 is the optimal range that balances the anti-collision effect of the front and rear ends. It can be adapted to engine operating conditions with different cylinder diameters and flow rates. At the same time, it provides sufficient adjustment space for fluid simulation optimization. The optimal offset distance can be customized for different engine platforms, making it highly versatile. The optimal offset range is a proprietary parameter obtained through extensive simulation and testing in this application and is not a conventional technical choice in this field.

[0052] In some examples of this embodiment, the matching relationship between the injection axis and the flow field is further refined. After the injection axis L1 is offset towards the rear end of the engine, the projection of the injection axis L1 onto the radial section of the downstream outlet straight section 25 falls within the high-speed mainstream airflow region of the downstream outlet straight section 25. The high-speed mainstream airflow region is the central flow channel region within the downstream outlet straight section 25 where the airflow velocity is not less than 1.2 times the average airflow velocity within the flow channel of the downstream outlet straight section 25. The high-speed mainstream airflow region is the area with the strongest airflow entrainment capacity within the intake manifold 2. By placing the injection axis into this region, the strong shearing and entrainment effect of the high-speed intake airflow can be utilized to quickly tear apart the methanol fuel jet, breaking large-diameter methanol fuel droplets into micron-sized fine droplets, significantly improving the atomization speed and atomization fineness of methanol fuel. Especially for low-speed airflow under cold start and low-speed operating conditions, it can effectively compensate for the difficulty of methanol fuel atomization and further improve the low-temperature atomization effect. The high-speed mainstream airflow zone is located in the central area of ​​the flow channel, far from the inner wall. Positioning the injection axis within this zone ensures the methanol fuel jet diffuses within the central flow channel, away from the wall. This further mitigates the risk of fuel jet 4 contacting the wall from a flow field matching perspective. Combined with the offset and angled designs of the core solution, this creates a synergistic effect, further reducing the fuel collision rate to below 15%. The airflow velocity in the high-speed mainstream zone exhibits the strongest synchronicity with changes in engine throttle opening and speed. Injecting the methanol fuel jet into this zone allows the methanol fuel to quickly enter the cylinder with the intake airflow, avoiding fuel retention issues in the low-speed near-wall area. This significantly improves fuel response speed during sudden changes in engine operating conditions, effectively enhancing engine acceleration performance and transient stability, and reducing the problem of overly rich / lean mixtures under transient conditions.

[0053] In some examples of this embodiment, such as Figure 1 and 3As shown, the mounting flange 21 at the end of the intake manifold 2 undergoes further structural optimization. The mounting flange 21 is a flange structure with a radial dimension larger than that of a conventional intake manifold 2 flange of the same model. On the end face of the mounting flange 21 that mates with the engine cylinder head, two annular sealing grooves are provided. These two annular sealing grooves are a first sealing groove 26 corresponding to the intake medium and a second sealing groove 27 corresponding to the coolant. Conventional intake manifold 2 flanges can only achieve a single-channel seal for the intake medium and cannot simultaneously connect to the cylinder head's cooling water jacket. This invention, through two independent sealing grooves on the enlarged flange, can simultaneously achieve independent sealing of the intake medium and coolant, without requiring additional openings or modifications to the main structure of the engine cylinder head. It only requires matching a conventional cylinder head cooling water jacket interface, significantly reducing engine modification costs and improving the versatility of the solution. Integrating the intake seal and coolant seal onto a single flange replaces the separate coolant piping, connectors, and sealing structures found in conventional solutions. This reduces the number of engine parts, simplifies assembly, and minimizes sealing points, thereby reducing the risk of coolant leakage at its source and improving the engine's long-term reliability. The enlarged flange has a larger radial dimension and significantly higher overall rigidity than conventional flanges. This effectively reduces flange deformation under engine vibration conditions, ensuring uniform pressure between the flange and cylinder head, preventing seal failure, air leakage, and fluid leakage caused by flange deformation, and greatly improving sealing reliability under all operating conditions.

[0054] In a further example of this embodiment, the circumferential layout of the two sealing grooves is further defined, such as... Figure 1 and 3 As shown, the second sealing groove 27 is arranged along the circumference of the mounting flange 21, at least partially surrounding the radial outer periphery of the first sealing groove 26. The second sealing groove 27 connects to the high-temperature cooling water jacket of the cylinder head, and its arrangement around the outer periphery of the first sealing groove 26 allows the heating range of the high-temperature coolant to completely cover the entire circumference of the intake passage inside the first sealing groove 26. This ensures that the heat from the flange is evenly transferred to the entire circumference of the intake passage, avoiding uneven local heating. It effectively increases the wall temperature of the intake passage and manifold outlet section, allowing the trace amounts of methanol fuel adhering to the wall to vaporize rapidly, further preventing oil film formation. This synergizes with the core solution's anti-collision wall design. The partial surrounding of the first sealing groove 26 maximizes the coverage length of the coolant sealing groove within the limited flange end face space, while ensuring sufficient solid wall thickness between the two sealing grooves. This does not reduce the structural rigidity of the flange, resulting in a compact and reasonable layout that does not require excessively increasing the radial dimension of the flange, making it suitable for the limited installation space in the engine compartment.

[0055] In other examples of this embodiment, the connection structure of the two sealing grooves is further optimized. The first sealing groove 26 and the second sealing groove 27 form an intersection connection area at at least one location in the circumferential direction through a shared groove wall. The shared groove wall within this intersection connection area is a solid wall integrally formed with the mounting flange 21. This shared groove wall completely isolates the internal cavities of the first sealing groove 26 and the second sealing groove 27, preventing them from communicating with each other. The intersection connection area formed by the two sealing grooves through the shared groove wall allows for the use of an integrated rubber sealing gasket. This enables simultaneous alignment of both sealing grooves in a single installation, solving the problems of misalignment and loosening common in conventional split-type seals. This significantly improves the batch assembly efficiency of the engine and avoids sealing failure caused by assembly misalignment. The shared tank wall is a continuous solid metal structure, which allows the heat of the high-temperature coolant in the second sealing tank 27 to be transferred more quickly and evenly to the air intake area around the first sealing tank 26 through the shared tank wall. This reduces the air insulation gap between the two sealing tanks, improves the heat conduction efficiency and heating uniformity of the mounting flange 21, further enhances the heating effect on the manifold outlet section, and helps improve methanol atomization.

[0056] In some further examples of this embodiment, the function and synergistic heating effect of the sealing groove are further refined. The second sealing groove 27 is used to connect and seal with the cooling water jacket of the engine cylinder head, so that the mounting flange 21 and the cylinder head cooling water jacket form direct heat conduction to indirectly heat the downstream outlet straight section 25. The intake pipe indirectly heats the downstream outlet straight section 25 through the heat conduction between the mounting flange 21 and the cylinder head cooling water jacket, increasing the wall temperature of the intake manifold 2. This allows the small amount of methanol fuel in contact with the wall to vaporize quickly without forming a stable oil film. The two work synergistically to provide a double guarantee, solving the problem of methanol fuel adhering to the wall of the intake manifold 2. Even under extreme low temperature and low speed conditions, it can ensure that no harmful oil film forms. The heating zone is the downstream outlet straight section 25, which is the installation location of the methanol injector 3. It directly heats the manifold wall and intake airflow in the injection area, allowing the methanol fuel to be in a higher temperature environment immediately after injection. This significantly increases the methanol evaporation rate, and the atomization assistance effect is far superior to upstream flow channel heating solutions. Especially for cold start conditions, it can quickly increase the wall temperature of the injection area, improving cold start atomization. This solution only heats a short section of the downstream outlet straight section 25, without heating the entire intake airflow in the intake manifold 1. This avoids the problem of reduced engine intake volume coefficient and power caused by an overall increase in intake temperature, ensuring that atomization assistance is achieved while maintaining the engine's power performance.

[0057] In some examples of this embodiment, the flow field structure of the intake manifold is further optimized. The inner wall of the intake manifold 1 is provided with at least one streamlined guide rib extending along the airflow direction within the intake manifold 1. The protrusion height of the guide rib is 1 / 20 to 1 / 10 of the inner diameter of the intake manifold 1. After the airflow enters the intake manifold 1 from the throttle valve, it is very easy to generate large-scale turbulence and eddies, resulting in uneven airflow distribution in each intake manifold 2, which in turn causes inconsistent air-fuel mixture concentration and uneven combustion in each cylinder. This solution, through the streamlined guide rib, can effectively streamline the airflow within the intake manifold 1, suppress the generation of large-scale turbulence, and allow the airflow to be more evenly distributed to each cylinder intake manifold 2. It can control the intake unevenness of each cylinder to within 2%, significantly improve the combustion balance of each cylinder, and reduce engine vibration and noise.

[0058] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0059] Although exemplary embodiments of the invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the invention without departing from the central concepts of the invention described herein. Therefore, the invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the invention.

Claims

1. A methanol injection nozzle offset intake pipe, comprising an intake manifold and a plurality of intake manifolds communicating with the intake manifold, wherein each intake manifold has a mounting flange at its end for mating with an engine cylinder head, characterized in that: Each intake manifold has a concave injector mounting surface on the outer wall of its arc-shaped flow channel. A methanol injection hole is provided on the concave injector mounting surface, and the methanol injection hole is used to install a methanol injector. The central axis of the methanol injection hole is the injection axis of the methanol injector. The injection axis is offset parallel to the rear end of the engine in the horizontal plane of the engine's normal installation state, relative to the flow channel central axis of the corresponding intake manifold at the injection hole installation position. The design angle between the boundary oil jet near the engine front end and the inner wall of the intake manifold on that side is 20°, which is used to control the amount of contact between the oil jet on that side and the inner wall of the intake manifold on that side. The offset arrangement of the injection axis is set in conjunction with the 20° design angle so that the proportion of the injected methanol fuel that contacts the inner wall of the intake manifold does not exceed 20%.

2. The methanol nozzle offset inlet pipe according to claim 1, characterized in that: The intake manifold includes an upstream curved flow channel section connected to the main intake pipe and a downstream outlet straight section rigidly connected to the mounting flange. The upstream curved flow channel section and the downstream outlet straight section are smoothly connected. The concave injector mounting plane is disposed on the outer wall of the downstream outlet straight section.

3. The methanol nozzle offset inlet pipe according to claim 2, characterized in that: The central axis of the methanol injection orifice is not offset in the radial height direction relative to the central axis of the downstream outlet straight section.

4. The methanol nozzle offset inlet pipe according to claim 2, characterized in that: The projection of the injection axis onto the radial section of the downstream outlet straight section falls within the high-speed mainstream airflow zone of the downstream outlet straight section; the high-speed mainstream airflow zone is the central flow channel region within the downstream outlet straight section where the airflow velocity is not less than 1.2 times the average airflow velocity within the downstream outlet straight section flow channel.

5. The methanol nozzle offset inlet pipe according to claim 2, characterized in that: The vertical distance by which the injection axis is offset parallel to the center axis of the flow channel of the corresponding downstream outlet straight section is 1 / 10 to 1 / 3 of the width of the flow channel of the downstream outlet straight section. The offset distance is determined by fluid simulation optimization.

6. The methanol nozzle offset inlet pipe according to claim 2, characterized in that: The mounting flange is a flange structure with a radial dimension larger than that of the conventional intake manifold flange of the same model. On the end face of the mounting flange that mates with the engine cylinder head, there are two independent annular sealing grooves. The two annular sealing grooves are the first sealing groove corresponding to the intake medium and the second sealing groove corresponding to the coolant.

7. The methanol nozzle offset inlet pipe according to claim 6, characterized in that: The second sealing groove is disposed along the circumference of the mounting flange, at least partially surrounding the radial outer periphery of the first sealing groove.

8. The methanol nozzle offset inlet pipe according to claim 7, characterized in that: The first sealing groove and the second sealing groove form an intersection and connection area at at least one position in the circumferential direction through a shared groove wall. The shared groove wall in the intersection and connection area is a solid wall integrally formed with the mounting flange. The shared groove wall completely isolates the internal cavities of the first sealing groove and the second sealing groove, and they are not connected to each other.

9. The methanol nozzle offset inlet pipe according to claim 8, characterized in that: The second sealing groove is used to connect and seal with the cooling water jacket of the engine cylinder head, so that the mounting flange and the cylinder head cooling water jacket form direct heat conduction to indirectly heat the downstream outlet straight section.

10. The methanol nozzle offset inlet pipe according to claim 1, characterized in that: The inner wall of the intake manifold is provided with at least one streamlined guide rib extending along the airflow direction inside the intake manifold, and the protrusion height of the guide rib is 1 / 20 to 1 / 10 of the inner diameter of the intake manifold flow channel.

Images