Combustion system, engine and vehicle

Abstract

The invention relates to a combustion system, an engine and a vehicle. The combustion system comprises an air inlet channel, an exhaust channel, an air inlet valve, an exhaust valve, a cylinder cover, a cylinder sleeve and a piston, a cylinder cover combustion chamber is arranged in the combustion system, and at least one of the inner surface of the cylinder cover combustion chamber, the surface, facing the interior of the combustion system, of the air inlet valve, the surface, facing the interior of the combustion system, of the exhaust valve and the top surface of the piston is provided with a thermal barrier coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles and engines, and more particularly to a combustion system. BACKGROUND

[0002] Improving the thermal efficiency of vehicle engines is one of the important means to reduce vehicle carbon emissions. Using lean-burn technology can make the effective thermal efficiency of gasoline engine products break through 45%, and even reach 50%. Mechanically, the contribution of lean-burn is multifaceted, including increasing the adiabatic index of in-cylinder working medium, reducing heat transfer loss, suppressing knock, and reducing pump loss at part load conditions. Among them, lean-burn needs to be combined with other technologies to maximize the potential for improving thermal efficiency.

[0003] The information provided in this section is for the purpose of presenting the background of the present application only, and therefore can include information that does not constitute prior art in the field. SUMMARY

[0004] The present application aims to solve or at least alleviate one or more problems existing in the prior art.

[0005] An aspect of the present application relates to a combustion system, comprising: an intake port, an exhaust port, an intake valve, an exhaust valve, a cylinder head, a cylinder liner, a piston, a cylinder head combustion chamber is provided in the combustion system, the intake port and the exhaust port are integrated on the cylinder head, the intake valve and the exhaust valve are provided on the cylinder head to control the intake and exhaust of the combustion system, the piston reciprocates in the cylinder liner, characterized in that at least one of the inner surface of the cylinder head combustion chamber, the surface of the intake valve facing the inside of the combustion system, the surface of the exhaust valve facing the inside of the combustion system, and the top surface of the piston is provided with a thermal barrier coating.

[0006] In an embodiment of the present application, optionally, the thermal conductivity of the thermal barrier coating on the inner surface of the cylinder head combustion chamber and / or the surface of the intake valve facing the inside of the combustion system and / or the surface of the exhaust valve facing the inside of the combustion system is higher than the thermal conductivity of the thermal barrier coating on the top surface of the piston.

[0007] In an embodiment of the present application, optionally, the thermal barrier coating on the inner surface of the cylinder head combustion chamber and / or the surface of the intake valve facing the inside of the combustion system and / or the surface of the exhaust valve facing the inside of the combustion system is a mixture of yttrium trioxide and zirconium dioxide, and the thermal conductivity of the mixture is in the range of 2.09-2.3 W / (m*K).

[0008] In an embodiment of the present application, optionally, the thermal barrier coating on the top surface of the piston is an epoxy silane having a thermal conductivity in the range of 0.85-1.4 W / (m*K) and a specific heat capacity less than or equal to 1600 kJ / (m 3 *K).

[0009] In an embodiment of the present application, optionally, the intake port is fish belly shaped to have a tumble ratio in the range of 2.6-2.8.

[0010] In an embodiment of the present application, optionally, the compression ratio of the combustion system is in the range of 15-17.

[0011] In an embodiment of the present application, optionally, the lift curve of the intake valve is an Atkinson cycle.

[0012] In an embodiment of the present application, optionally, the combustion system is a lean burn system having a lean burn limit of 1.9 for excess air ratio.

[0013] Another aspect of the present application relates to an engine having the combustion system of any one of the above.

[0014] The present application also relates to a vehicle having the combustion system of any one of the above. BRIEF DESCRIPTION OF DRAWINGS

[0015] The disclosure of the present application will become more apparent with the reference to the drawings. It is readily understood by a person skilled in the art that the drawings are merely for the purpose of illustration and are not intended to limit the scope of protection of the present application. In addition, similar numbers are used to represent similar components throughout the drawings, in which: Figure 1 a schematic view of a combustion system according to one embodiment is shown; Figure 2 a schematic view of another angle of a combustion system according to one embodiment is shown; Figure 3 a schematic view of a piston top of a combustion system according to one embodiment is shown; Figure 4 a schematic view of an intake port of a combustion system according to one embodiment is shown.

[0016] List of reference numerals: intake port 1, exhaust port 2, intake valve 3, exhaust valve 4, cylinder head combustion chamber 5, top surface of the piston 6, cylinder liner 7, spark plug 8, fuel injection system 9. DETAILED DESCRIPTION

[0017] First of all, it needs to be explained that the composition, features and advantages of the combustion system, engine and vehicle according to the present application will be described below in an exemplary manner, but it should be understood that all the descriptions are given only for illustration and therefore should not be understood as forming any limitation on the present application. In this text, the technical terms "first", "second" are only used for the purpose of making a distinguishing description and are not intended to represent their order and relative importance. The description of "first technical feature A" related to technical feature A does not mean that there must be a corresponding "second technical feature A", and vice versa. The technical term "connection (or connection, etc.)" covers the direct connection of a specific component to another component and / or indirect connection to another component. In addition, unless otherwise explicitly specified and limited, the technical terms "length", "width", "height", "upper", "top", "bottom", etc. indicate the size, direction or position relationship based on the size, orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and cannot be understood as a limitation on the present application.

[0018] In addition, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the drawings, the present application still allows any combination or deletion between these technical features (or their equivalents) to continue without any technical obstacles, thereby obtaining more other embodiments of the present application that can not be directly mentioned herein. In addition, general matters that are well known to those skilled in the art are not described herein.

[0019] An aspect of the present application relates to a combustion system, for example, a combustion system of a gasoline engine. Referring to Figures 1-4 , the combustion system can include an intake passage 1, an exhaust passage 2, an intake valve 3, an exhaust valve 4, a cylinder head combustion chamber 5, a piston, a cylinder sleeve 7, a spark plug 8 and an oil injection system 9. Among them, the cylinder head combustion chamber 5 is arranged inside the combustion system; the intake passage 1 and the exhaust passage 2 are integrated on the cylinder head and connected with the cylinder head combustion chamber 5; the intake valve 3 and the exhaust valve 4 are assembled on the cylinder head and respectively seated on the valve circle seat of the cylinder head, which can open and seal the combustion system. Specifically, when the intake valve and the exhaust valve are both closed, the entire combustion system can be sealed, when the intake valve is opened, the intake process of the combustion system can be carried out, and when the exhaust valve is opened, the exhaust process can be carried out; the piston can reciprocate along the axis of the cylinder sleeve 7 for outputting mechanical work; the spark plug 8 is used to ignite the mixture of gasoline and air.

[0020] According to one embodiment of the present application, a thermal barrier coating is provided on at least one of the surface of the intake valve 3 facing the interior of the combustion system, the surface of the exhaust valve 4 facing the interior of the combustion system, the inner surface of the cylinder head combustion chamber 5, and the top surface 6 of the piston, for example, a thermal barrier coating is provided on all of the four surfaces. The thermal barrier coating can reduce the heat transfer to the surrounding wall surface when the mixture is combusted, for the purpose of reducing the heat transfer loss. In addition, the thermal barrier coating can also accelerate the evaporation of the wall-attached fuel, and reduce the particulate matter emission in the exhaust gas.

[0021] In one embodiment, the thermal conductivity of the thermal barrier coating on at least one of the inner surface of the cylinder head combustion chamber 5, the surface of the intake valve 3 facing the interior of the combustion system, the surface of the exhaust valve 4 facing the interior of the combustion system, for example, all of them, is higher than the thermal conductivity of the thermal barrier coating on the top surface 6 of the piston. For example, the thermal barrier coating on at least one of the inner surface of the cylinder head combustion chamber 5, the surface of the intake valve 3 facing the interior of the combustion system, the surface of the exhaust valve 4 facing the interior of the combustion system, for example, all of them, is a mixture of yttrium trioxide and zirconium dioxide, the composition ratio of which can be: yttrium trioxide 6-8%, the balance zirconium dioxide, the thermal conductivity of the mixture can be, for example, 2.09-2.3 W / (m*K). For example, the thermal barrier coating on the top surface of the piston can be an epoxy silane, the thermal conductivity of which can be, for example, 0.85-1.4 W / (m*K), the specific heat capacity of the epoxy silane thermal barrier coating can be less than or equal to 1600 kJ / (m 3 *K).

[0022] As shown in FIG. 6, it is another schematic view of the combustion system of one embodiment of the present application. In this embodiment, the combustion system adopts a single-cylinder four-valve arrangement, as can be seen from FIG. 6, in which the number of intake valves 3 and exhaust valves 4 is two each. Figure 2 Figure 2 As shown in FIG. 6, it is another schematic view of the combustion system of one embodiment of the present application. In this embodiment, the combustion system adopts a single-cylinder four-valve arrangement, as can be seen from FIG. 6, in which the number of intake valves 3 and exhaust valves 4 is two each.

[0023] Figure 4 A schematic view of the intake port 1 is shown, in which it can be seen that the lower part of the intake port 1 is designed in a fish belly shape, which can guide the intake flow to form a rolling flow after entering the cylinder, and the rolling flow ratio range can be 2.6-2.8. Through the fish belly design of the intake port, the turbulent kinetic energy of the in-cylinder mixture can be improved, thereby improving the combustion speed of the in-cylinder mixture.

[0024] The combustion system according to one embodiment of the present application can have a high compression ratio, which can reach 15-17. The meaning of the compression ratio is the ratio of the sum of the clearance volume when the piston is at the top dead center to the clearance volume when the piston is at the top dead center. In one example, the single-cylinder displacement of the combustion system is 0.375 L, the cylinder diameter is 74.5 mm, and the stroke is 85.9 mm.

[0025] ​According to one embodiment of the present application, the lift curve of the intake valve of the combustion system can adopt the Atkinson cycle. In combination with the high compression ratio described above, using the Atkinson cycle, i.e. the late intake valve closing technology, can reduce the compression ratio of the actual compression process to a certain extent while the expansion ratio remains 15-17. The specific implementation is to delay the closing of the intake valve to the early stage of the compression process, so that part of the intake charge is pushed back to the intake port, and thus only the remaining part of the intake charge actually participates in the compression process. Therefore, the Atkinson cycle makes the actual compression ratio less than the expansion ratio, which can not only inhibit the tendency of knocking, but also have a large enough expansion ratio to make the gas work fully.

[0026] In one embodiment, the fuel injection system 9 is a high-pressure in-cylinder direct injection system, and the fuel injection pressure ranges from 10 to 35 MPa. As shown in FIG. 1, the fuel injector is located below the intake port 1. Figure 1

[0027] According to one embodiment of the present application, the working medium used by the combustion system is a mixture composed of gasoline and air, and the lean combustion limit of which can be stably combusted is an excess air coefficient of 1.9. The theoretical air-fuel ratio of gasoline is 14.7, so when the excess air coefficient is 1.9, 27.93 g of air is matched with 1 g of gasoline in the mixture. Among them, the judgment standard for stable combustion is that the combustion cycle variation is less than 3%.

[0028] According to the disclosure of the present application, compared with the prior art, the compression ratio is further improved, the limit of lean combustion is expanded, and the heat transfer loss is reduced, thereby increasing the useful work outputted by the whole system to the outside, further improving the effective thermal efficiency of the combustion system, and reducing carbon emissions. The application of thermal barrier coating, lean combustion, and high-pressure in-cylinder direct injection technology also reduces the emission of harmful gaseous pollutants and particulate matter.

[0029] The specific embodiments described above of the present application are only for more clearly describing the principles of the present application, in which various components are clearly shown or described so that the principles of the present application are more easily understood. Those skilled in the art can easily make various modifications or changes to the present application without departing from the scope of the present application. Therefore, it should be understood that these modifications or changes should be included in the scope of patent protection of the present application.​

Claims

1. A combustion system, comprising: The system comprises an intake manifold, an exhaust manifold, an intake valve, an exhaust valve, a cylinder head, a cylinder liner, and a piston. The combustion system includes a cylinder head combustion chamber. The intake manifold and the exhaust manifold are integrated on the cylinder head. The intake valve and the exhaust valve are disposed on the cylinder head to control the intake and exhaust of the combustion system. The piston reciprocates within the cylinder liner. The system is characterized in that at least one of the inner surface of the cylinder head combustion chamber, the surface of the intake valve facing the interior of the combustion system, the surface of the exhaust valve facing the interior of the combustion system, and the top surface of the piston is provided with a thermal barrier coating.

2. The combustion system according to claim 1, characterized in that, The thermal conductivity of the thermal barrier coating on the inner surface of the cylinder head combustion chamber and / or the surface of the intake valve facing the interior of the combustion system and / or the surface of the exhaust valve facing the interior of the combustion system is higher than that of the thermal barrier coating on the top surface of the piston.

3. The combustion system according to claim 1, characterized in that, The thermal barrier coating on the inner surface of the cylinder head combustion chamber and / or the surface of the intake valve facing the interior of the combustion system and / or the surface of the exhaust valve facing the interior of the combustion system is a mixture of yttrium trioxide and zirconium dioxide, wherein the thermal conductivity of the mixture is in the range of 2.09-2.3 W / (m*K).

4. The combustion system according to claim 1, characterized in that, The thermal barrier coating on the top surface of the piston is epoxy silane, with a thermal conductivity in the range of 0.85-1.4 W / (m*K) and a specific heat capacity less than or equal to 1600 kJ / (m²). 3 *K).

5. The combustion system according to claim 1, characterized in that, The lower part of the air intake is shaped like a fish belly to ensure that the tumble ratio of the airflow entering the cylinder is in the range of 2.6-2.

8.

6. The combustion system according to claim 1, characterized in that, The compression ratio of the combustion system is in the range of 15-17.

7. The combustion system according to claim 1, characterized in that, The intake valve lift curve uses the Atkinson cycle.

8. The combustion system according to claim 1, characterized in that, The combustion system is a lean combustion system, and its lean combustion limit for stable combustion is an excess air coefficient of 1.

9.

9. An engine having a combustion system according to any one of claims 1-8.

10. A vehicle having a combustion system according to any one of claims 1-8.

Images