阅读说明：本技术 一种天然气发动机 (Natural gas engine ) 是由 丁光辉 张辰 李凯 陆荣荣 陈园明 赵文仲 周涛 豆刚 张增光 王书林 刘路 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种天然气发动机,包括缸体,缸体包括排气系统,其包括进气门和排气门,进气门与排气门之间的夹角为41°,且进气门的夹角为18°,排气门的夹角为23°；进气门和排气门与发动机缸盖的结合处设有气门座圈,气门座圈面向缸盖的一侧设有三处压紧面,三处压紧面构成连续性的阶梯结构；进气门的进气口处还连接有进气歧管,进气歧管整体为阿基米德螺旋线结构；燃气系统,其包括燃烧室与活塞,燃烧室面向活塞的一面为倒扣的弧面,活塞面向燃烧室的顶面设有凹陷部,凹陷部与弧面相配合。本发明是一种大动力大排量的燃气发动机,其缸径较大,缸套较长。从燃烧系统、点火系统等方面解决了大缸径发动机所必然存在易爆震、燃烧困难的情况。(The invention discloses a natural gas engine, which comprises a cylinder body, wherein the cylinder body comprises an exhaust system, the exhaust system comprises an air inlet valve and an exhaust valve, an included angle between the air inlet valve and the exhaust valve is 41 degrees, the included angle between the air inlet valve is 18 degrees, and the included angle between the exhaust valve is 23 degrees; the joint of the intake valve, the exhaust valve and the engine cylinder cover is provided with a valve seat ring, one side of the valve seat ring facing the cylinder cover is provided with three pressing surfaces, and the three pressing surfaces form a continuous stepped structure; an air inlet of the air inlet valve is also connected with an air inlet manifold, and the whole air inlet manifold is of an Archimedes spiral line structure; the gas system comprises a combustion chamber and a piston, wherein one surface of the combustion chamber facing the piston is an inverted cambered surface, a concave part is arranged on the top surface of the piston facing the combustion chamber, and the concave part is matched with the cambered surface. The invention relates to a large-power large-displacement gas engine, which has a larger cylinder diameter and a longer cylinder sleeve. The problems that the large-cylinder-diameter engine is easy to knock and difficult to burn are solved from the aspects of a combustion system, an ignition system and the like.)

1. A natural gas engine comprising a cylinder block, the cylinder block comprising:

the exhaust system comprises an air inlet valve and an exhaust valve, an included angle is formed between the air inlet valve and the exhaust valve and is 41 degrees, the included angle comprises an included angle of the air inlet valve and an included angle of the exhaust valve, the included angle of the air inlet valve is 18 degrees, and the included angle of the exhaust valve is 23 degrees; a valve seat ring is arranged at the joint of the intake valve, the exhaust valve and an engine cylinder cover, and three pressing surfaces are arranged on one side of the valve seat ring facing the cylinder cover and form a continuous stepped structure; an air inlet of the air inlet valve is also connected with an air inlet manifold, and the whole air inlet manifold is of an Archimedes spiral line structure;

the gas system comprises a combustion chamber and a piston, wherein one surface of the combustion chamber facing the piston is a reversed cambered surface, the piston faces the top surface of the combustion chamber and is provided with a concave part, and the concave part is matched with the cambered surface.

2. The natural gas engine of claim 1, wherein the compression surface in the middle of the valve seat ring is of an inclined structure, and the compression surfaces on the other two sides are of a planar structure.

3. The natural gas engine of claim 2, wherein adjacent compression faces and between the compression faces and other connection faces are chamfered.

4. The natural gas engine of claim 1, wherein the exhaust system further comprises an intake valve and an exhaust valve, the intake valve having a valve diameter to cylinder diameter ratio of 0.396, the exhaust valve having a valve diameter to cylinder diameter ratio of 0.33.

5. The natural gas engine of claim 1 wherein the plenum chamber of the intake manifold is a semi-circular block structure and the intake manifold connects the straight ends of the plenum chamber.

6. The natural gas engine of claim 1 wherein the contact surface of the piston with the combustion chamber is machined for smooth surface finish.

7. The natural gas engine of claim 1 further comprising an air pump disposed on a flywheel housing at the rear end of the engine and driven by the crankshaft.

8. The natural gas engine of claim 7, wherein the flywheel housing is made of cast aluminum.

9. The natural gas engine of claim 1, wherein a head shroud is provided on the head, the head shroud being made of cast aluminum.

10. The natural gas engine of any one of claims 1 to 9, wherein the natural gas engine is an in-line four cylinder gas engine.

Technical Field

The invention relates to the technical field of automobile gas power, in particular to a natural gas engine.

Background

Among various automobile alternative fuels, natural gas is receiving attention because of its cleanliness, large reserves, high calorific value, low pollution discharge, and good economical efficiency of use. The development of natural gas automobiles has important practical significance for improving the urban air quality and relieving the energy pressure in China. With the comprehensive through of the west-east gas transportation engineering and the large-scale landing of overseas oil and gas, natural gas is gradually becoming the most important energy transformation support at present.

With the promotion of natural gas by national strategic planning, the natural gas product proportion is gradually increased in recent years. Meanwhile, with the implementation of national six-emission diesel, the natural gas product is relatively easy to be discharged and upgraded, has the advantages of low usage and the like, and has new opportunities in the natural gas market. The large-displacement power product with the advantages of good environmental adaptability, low cost, compact arrangement, strong power, good economy and the like is lacked. At present, more than 3L of in-line gas engine products are lacked in the automobile industry at home and abroad, and the six-cylinder engine can not meet the requirements of commercial vehicles in terms of cost and compactness.

Therefore, how to provide a large-power large-displacement gas engine which can effectively avoid the problems of difficult combustion and easy detonation due to large cylinder diameter becomes a technical problem which needs to be solved urgently in the field.

Disclosure of Invention

The invention aims to provide a natural gas engine which is large in displacement, strong in low-end rotating speed power (the torque of 1000rpm reaches more than 250 Nm), simple in structure, free of pressurization of in-line four cylinders and high in reliability.

According to an aspect of the present invention, there is provided a natural gas engine comprising a cylinder block including therein:

the exhaust system comprises an air inlet valve and an exhaust valve, an included angle is formed between the air inlet valve and the exhaust valve and is 41 degrees, the included angle comprises an included angle of the air inlet valve and an included angle of the exhaust valve, the included angle of the air inlet valve is 18 degrees, and the included angle of the exhaust valve is 23 degrees; a valve seat ring is arranged at the joint of the intake valve, the exhaust valve and an engine cylinder cover, and three pressing surfaces are arranged on one side of the valve seat ring facing the cylinder cover and form a continuous stepped structure; an air inlet of the air inlet valve is also connected with an air inlet manifold, and the whole air inlet manifold is of an Archimedes spiral line structure;

the gas system comprises a combustion chamber and a piston, wherein one surface of the combustion chamber facing the piston is a reversed cambered surface, the piston faces the top surface of the combustion chamber and is provided with a concave part, and the concave part is matched with the cambered surface.

Optionally, according to the natural gas engine of the present invention, the pressing surface located in the middle of the valve seat ring is an inclined structure, and the pressing surfaces on the other two sides are a planar structure.

Optionally, according to the natural gas engine of the present invention, chamfering is performed between adjacent compression surfaces and between the compression surface and other connection surfaces.

Optionally, according to the natural gas engine of the present invention, the exhaust system further comprises an intake valve and an exhaust valve, the ratio of the valve diameter of the intake valve to the cylinder diameter is 0.396, and the ratio of the valve diameter of the exhaust valve to the cylinder diameter is 0.33.

Optionally, according to the natural gas engine of the present invention, the surge tank of the intake manifold is a semicircular block structure, and the intake manifold is connected to a linear end of the surge tank.

Optionally, according to the natural gas engine of the present invention, the contact surface between the piston and the combustion chamber is machined to be smooth.

Optionally, the natural gas engine according to the invention further comprises an air pump which is arranged on a flywheel housing at the rear end of the engine and is driven by the crankshaft.

Optionally, in the natural gas engine according to the invention, the flywheel housing is made of cast aluminium.

Optionally, according to the natural gas engine of the present invention, a cylinder head shield is disposed on the cylinder head, and the cylinder head shield is made of cast aluminum.

Optionally, the natural gas engine according to the invention is an in-line four cylinder gas engine.

The natural gas engine disclosed by the invention is a large-power large-displacement gas engine, the cylinder diameter of the natural gas engine is larger, and the cylinder sleeve is longer. Meanwhile, the invention solves the problems of easy knock and difficult combustion of the large-cylinder-diameter engine in the aspects of a combustion system, an ignition system and a heat management system. The included angle between the intake valve and the exhaust valve is increased, so that the turbulence intensity is improved, the flame propagation speed is accelerated, and the detonation tendency is reduced; in addition, the structure of the valve seat ring is adjusted, so that the valve seat ring is better matched with a cylinder cover.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a perspective view of a cylinder block of the disclosed natural gas engine;

FIG. 2 is a perspective view of the intake and exhaust valves disclosed herein;

FIG. 3 is a schematic illustration of the assembly of the disclosed valve seat insert;

FIG. 4 is a schematic illustration of the disclosed valve seat insert configuration;

FIG. 5 is a schematic illustration of an intake valve according to the present disclosure;

FIG. 6 is a schematic view of a vent valve according to the present disclosure;

FIG. 7 is a top view of the disclosed piston;

FIG. 8 is a side view (one) of the disclosed natural gas engine;

FIG. 9 is a side view of the disclosed natural gas engine (two);

FIG. 10 is a schematic illustration of an intake manifold as disclosed herein.

Description of reference numerals: 1-a cylinder body; 2-an intake valve; 21-an air inlet valve; 3-an exhaust valve; 31-an exhaust valve; 4-valve seat ring; 41-a pressing surface; 5-cylinder cover; 6-cylinder cover shield; 7-air pump; 8-flywheel housing; 10-intake manifold.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

According to fig. 1 to 10, the present invention provides a natural gas engine, which comprises a cylinder block 1, wherein the cylinder block 1 comprises: the exhaust system comprises an intake valve 2 and an exhaust valve 3, wherein an included angle of 41 degrees is formed between the intake valve 2 and the exhaust valve 3, and the included angle comprises an included angle of the intake valve 2 and an included angle of the exhaust valve 3; the included angle between the intake valve 2 and the vertical plane is 18 degrees, and the included angle between the exhaust valve 3 and the vertical plane is 23 degrees; a valve seat ring 4 is arranged at the joint of the intake valve 2, the exhaust valve 3 and an engine cylinder cover 5, three pressing surfaces 41 are arranged on one side of the valve seat ring 4 facing the cylinder cover 5, and the three pressing surfaces 41 form a continuous stepped structure; and the air inlet of the air inlet valve 2 is also connected with an air inlet manifold 9, and the whole air inlet manifold 9 is of an Archimedes spiral line structure. In the implementation process, the design of a 41-degree valve included angle is adopted between the intake valve 2 and the exhaust valve 3, and the turbulent intensity can be improved by a large valve included angle, so that the flame propagation speed is accelerated, and the detonation tendency is reduced. The 2 contained angles of big (air) intake valve are favorable to the design of high tumble air flue, but are unfavorable for the tumble breakage and improve the compression ratio to too big valve contained angle, combine the air flue structure, carry out the CAE analysis to air flue is experimental, confirms that engine valve contained angle decides to be 41, and the air inlet contained angle is decided for 18 (the contained angle again can lead to the engine too wide, is unfavorable for arranging of engine, and influences the pressure equipment that intake valve 2 arranged and valve seat circle 4), and the exhaust contained angle is decided for 23.

The gas system, it includes combustion chamber and piston 10, the combustion chamber face the one side of piston 10 is the cambered surface of back-off, piston 10 face the top surface of combustion chamber is equipped with the depressed part, the depressed part with the cambered surface cooperatees. In implementation, the top of the piston 10 adopts an inverted cambered surface, part of the combustion chamber of the cylinder cover 5 adopts an innovative awning-shaped structure (as shown in fig. 7), the dead volume is reduced, and through machining processes (two machining surfaces respectively) of the top of the piston 10 and the cylinder cover 5, the smoothness is improved, the tumble flow is easy to form, the friction coefficient is lower, and the turbulent kinetic energy can reach more than 380m2/s 2. Compared with a casting structure, the machining precision is high, the compression ratio tolerance of the engine is small, the performance consistency of the engine is good, and the knocking of the engine is reduced.

Further, the pressing surface 41 located in the middle of the valve seat 4 has an inclined structure, and the pressing surfaces 41 on the other two sides have a planar structure. In the implementation, in order to realize the design of the air passage with high tumble ratio, the design of a 41-degree valve included angle is matched, and a special-shaped valve seat ring 4 structure is adopted. Because the valve contained angle is great, and will guarantee the design of high tumble ratio air flue structure, the valve seat insert 4 headspace reduces, and qualified pressure equipment power can't be guaranteed to conventional seat insert, adopts special-shaped seat insert structure can increase and the interference fit length of cylinder cap 5. In order to improve the tumble ratio, the included angle between the air inlet passage structure and the combustion chamber is reduced as much as possible, so that the space of the valve seat ring 4 is smaller, if the seat ring with the conventional structure is smaller in the contact surface between the seat ring and the base of the cylinder cover 5, and the seat ring is easy to fall off, the special-shaped double-step structure is adopted, two step-shaped structures are added, as shown in figure 4, the number of the matching surfaces of the special-shaped double-step structure and the cylinder cover 5 is increased to three from one surface, and the contact surface between the valve seat ring 4 and the cylinder cover 5 can be increased by 30% in the limited space (the contact area is only 4.5mm in the conventional seat ring structure, and the structure can reach 6.0 mm).

Furthermore, chamfering processing is performed between the adjacent pressing surfaces 41 and between the pressing surfaces 41 and other connecting surfaces, so that the compression deformation and fracturing of the seat ring and the base in the press fitting process are prevented.

Further, the exhaust system further comprises an intake valve 21 and an exhaust valve 31, the ratio of the valve diameter of the intake valve 21 to the cylinder diameter is 0.396, and the ratio of the valve diameter of the exhaust valve 31 to the cylinder diameter is 0.33. In implementation, the invention also adopts the design of the valve diameter of the large-size intake and exhaust valve 3: according to the formula Q ═ v · pi · D_v ²[ 4 ]/[ means for increasing intake air flow, the diameter of the intake valve 21 of the large-displacement target engine is designed to be 38mm, the diameter of the exhaust valve 31 is 31.7mm, the Dv/D (valve diameter/cylinder diameter) of intake air reaches 0.396, and the Dv/D of exhaust air reaches 0.33, which are all at the advanced level in the world and have large sizeThe valve diameter of the exhaust valve 3 is beneficial to forming a large flow coefficient.

Further, the surge tank 91 of the intake manifold 9 is a semicircular block structure, and the intake manifold 9 is connected to a linear end of the surge tank 91. Computational analysis according to CAE: according to the design of a common sample line structure, the average value of flow coefficients of all cylinders is 0.676, the uniformity is maximum to be 1.24 percent, and the air inlet resistance of a manifold is 268 Pa. Designed by following the Archimedes spiral principle (as shown in figure 10), the flow coefficient of each cylinder has the average value of 0.7473 (10.55 percent improvement), the uniformity is 0.37 percent at most, and the manifold intake resistance is only 234 Pa. Therefore, an Archimedes spiral line structure scheme is selected, and technical conditions are provided for realizing the air passage design with high tumble ratio and high flow coefficient. Meanwhile, the structure of the voltage stabilizing cavity 91 is optimized from a cuboid-like structure to a cylinder-like structure, which is also beneficial to reducing noise.

Further, the contact surface of the piston 10 and the combustion chamber is machined smoothly. In implementation, the smoothness is improved, the tumble flow is easy to form, the friction coefficient is lower, and the turbulence energy can reach more than 380m2/s2 through the machining process of the top of the piston 10 and the combustion chamber. Compared with a casting structure, the machining precision is high, the compression ratio tolerance of the engine is small, the performance consistency of the engine is good, and the knocking of the engine is reduced.

Further, the brake device also comprises an air pump 7, wherein the air pump 7 is arranged on a flywheel shell 8 at the rear end of the engine and is driven by a crankshaft, and a high-efficiency and reliable brake power source can be provided.

Still further, the flywheel housing 8 is made of cast aluminum, and the flywheel housing 8 can be adjusted to adapt to gearboxes with different sizes and forms, so that the cylinder body 1 does not need to be modified.

Further, be equipped with cylinder head guard shield 6 on the cylinder cap 5, cylinder head guard shield 6 is made by cast aluminum, possesses the advantage of arranging compactly.

Further, the natural gas engine is an in-line four-cylinder gas engine.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.