Air inlet system for compressed natural gas engine

Abstract

The utility model discloses an air inlet system for a compressed natural gas engine, which is characterized in that an air inlet end of an air inlet manifold is provided with a throttle valve, the throttle valve is connected with an air compression assembly, a pressure stabilizing cavity is arranged in the air inlet manifold, an air outlet of the throttle valve is communicated with the pressure stabilizing cavity, the air inlet manifold is provided with a plurality of branch pipes, and mixing cavities are arranged in the branch pipes; the branch pipe is further provided with an air injection hole and an oil injection hole, the air injection hole and the oil injection hole are both communicated with the mixing cavity, an air injection assembly is installed in the air injection hole, and an oil injection assembly is installed in the oil injection hole. The utility model has the beneficial effects that when the engine is started at a low temperature, fuel oil combustion is adopted, and when the cooling liquid of the engine reaches a set temperature, the fuel oil combustion is switched into combustible gas combustion, so that the problem that the pressure reducer cannot be well heated due to lower temperature of the cooling liquid of the engine when the engine is started at a low temperature is solved; and water vapor in the natural gas is easy to separate out and freeze on the surface of the pressure reducer.

Description

Technical Field

[0001] The utility model relates to an air intake system for an exhaust gas turbocharger engine, in particular to an air intake system for a compressed natural gas engine. Background Art

[0002] The main component of compressed natural gas is methane CH4, and there are small amounts of CO2, H2S, H2O, CO, etc. There is an important component on the compressed natural gas engine called the pressure reducer, where the compressed natural gas is decompressed and expanded. In this process, the natural gas absorbs heat, resulting in a very low temperature in the pressure reducer. In order to ensure the normal operation of the pressure reducer, the engine coolant is generally used to heat the pressure reducer. When the engine is in normal working condition, the temperature of the coolant is generally around 90°C. There is no problem in heating the pressure reducer with coolant at this temperature. However, when the engine is cold-started at low temperature, the engine coolant temperature is low and cannot heat the pressure reducer well. The water vapor in the natural gas is easy to precipitate and freeze on the surface of the pressure reducer. Utility Model Content

[0003] The utility model aims to overcome the shortcomings of the prior art and provide an air intake system for a compressed natural gas engine.

[0004] The purpose of the utility model is achieved through the following technical solutions: an intake system for a compressed natural gas engine, including an intake manifold, a throttle is installed at the intake end of the intake manifold, the throttle is connected to an air compression assembly, a pressure stabilizing chamber is provided in the intake manifold, an air outlet of the throttle is connected to the pressure stabilizing chamber, a plurality of branch pipes are provided on the intake manifold, a mixing chamber is provided in the branch pipes, and the mixing chamber is connected to the pressure stabilizing chamber, an injection hole and an oil injection hole are also provided on the branch pipes, both the injection hole and the oil injection hole are connected to the mixing chamber, an injection assembly is installed in the injection hole, an oil injection assembly is installed in the oil injection hole, the injection assembly and the oil injection assembly are connected to a vehicle-mounted computer, and the vehicle-mounted computer controls the operation of the injection assembly and the oil injection assembly.

[0005] Optionally, the jet assembly includes an air rail and an air jet nozzle, the air outlet end of the air jet nozzle is connected to the jet hole, the air inlet end of the air jet nozzle is connected to the air rail, and the air rail is installed on the intake manifold.

[0006] Optionally, at least two air rail fixing laps are provided on the intake manifold, and fixing plates corresponding to the air rail fixing laps are provided on the air rail, and the fixing plates are fastened to the corresponding air rail fixing laps by screws.

[0007] Optionally, the fuel injection assembly includes a fuel rail and a fuel injection nozzle, the fuel outlet end of the fuel injection nozzle is connected to the fuel injection hole, the fuel inlet end of the fuel injection nozzle is connected to the fuel rail, and the fuel rail is installed on the intake manifold.

[0008] Optionally, at least two oil rail fixing brackets are provided on the intake manifold, and fixing plates corresponding to the oil rail fixing brackets are provided on the oil rail, and the fixing plates are fastened to the corresponding oil rail fixing brackets by screws.

[0009] Optionally, there are four branch pipes, and the four branch pipes are connected in parallel.

[0010] Optionally, the axis line of the oil injection hole is parallel to the axis line of the air injection hole.

[0011] The utility model has the following advantages: the air intake system for a compressed natural gas engine of the utility model adopts fuel combustion when the engine is started at low temperature, and when the engine coolant reaches a specified temperature, the fuel combustion is switched to combustible gas combustion, thereby solving the technical problem that when the engine is cold started at low temperature, the water vapor in the natural gas is easy to precipitate and freeze on the surface of the pressure reducer because the engine coolant temperature is low and the pressure reducer cannot be heated well. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] Figure 2 It is a cross-sectional schematic diagram of the utility model;

[0014] In the figure, 1-throttle valve, 2-intake manifold, 3-air rail, 4-air rail fixing bracket, 5-oil rail, 6-oil rail fixing bracket, 7-injection nozzle, 8-fuel injection nozzle, 21-pressure stabilizing chamber, 22-mixing chamber, 23-injection hole, 24-injection hole, 25-branch pipe, 31-fixed plate, 51-fixed plate. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0019] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] like Figure 1 and Figure 2As shown, an intake system for a compressed natural gas engine includes an intake manifold 2, a throttle valve 1 is installed at the intake end of the intake manifold 2, the throttle valve 1 is connected to the air compression assembly, a pressure stabilizing chamber 21 is provided in the intake manifold 2, and the air outlet of the throttle valve is communicated with the pressure stabilizing chamber 21. Fresh air that has been pressurized or intercooled enters the pressure stabilizing chamber 21 through the throttle valve 1, and the intake manifold 2 has a plurality of branch pipes 25, and a mixing chamber 22 is provided in the branch pipes 25, and the mixing chamber 22 is communicated with the pressure stabilizing chamber 21. The gas entering the pressure stabilizing chamber 21 is distributed to each The branch pipe 25 is provided with an injection hole 24 and an oil injection hole 23. The injection hole 24 and the oil injection hole 23 are both connected to the mixing chamber 22. The injection hole 24 is provided with an injection assembly, and the oil injection hole 23 is provided with an injection assembly. In this embodiment, the branch pipe 25 is connected to the intake passage of the engine cylinder head. Therefore, fresh air and natural gas or fuel are mixed in the branch pipe 25 and then enter the combustion chamber through the intake passage of the engine cylinder head for combustion. In this embodiment, when the engine is started, the injection assembly stops working, that is, the injection assembly does not enter the mixing chamber at this time. The fuel injection assembly works at this time. After the fuel injection assembly injects fuel into the mixing chamber 22, the oil and gas are mixed and enter the combustion chamber through the engine cylinder head intake duct for combustion. After combustion, the engine coolant is heated up. When the engine coolant reaches about 90°C, the fuel injection assembly stops working and the jet assembly works. The jet assembly injects combustible gas into the mixing chamber 22. The mixed gas enters the combustion chamber through the engine cylinder head intake duct for combustion. Therefore, when the engine is started, fuel combustion is adopted. When the engine is working normally, , and then switch to combustible gas combustion, thereby avoiding the phenomenon that when the engine is cold started at low temperature, the water vapor in the natural gas is easy to precipitate and freeze on the surface of the pressure reducer because the engine coolant temperature is low and the pressure reducer cannot be heated well. Of course, in this embodiment, the jet assembly and the fuel injection assembly are connected to the on-board computer (ECU), and the on-board computer controls the operation of the jet assembly and the fuel injection assembly. The on-board computer belongs to the prior art, and the on-board computer controls the operation of the jet assembly and / or the fuel injection assembly, which also belongs to the prior art, and its specific control logic will not be repeated.

[0022] In this embodiment, if Figure 1 and Figure 2As shown, the jet assembly includes an air rail 3 and an air jet nozzle 7, the air outlet end of the air jet nozzle 7 is connected to the air jet hole 24, the air inlet end of the air jet nozzle 7 is connected to the air rail 3, the air rail 3 is installed on the intake manifold 2, further, at least two air rail fixing brackets 4 are provided on the intake manifold 2, and the air rail 3 is provided with fixing plates 31 corresponding to the air rail fixing brackets 4, and the fixing plates 31 are locked with the corresponding air rail fixing brackets 4 by screws, that is, the air rail fixing brackets 4 are provided with screw holes, and the fixing plates 31 are provided with through holes for the screws to pass through. When the air rail 3 is installed, the fixing plates 31 can be bent and processed according to the installation position of the air rail 3.

[0023] In this embodiment, if Figure 1 and Figure 2 As shown, the fuel injection assembly includes an oil rail 5 and a fuel injection nozzle 8, the oil outlet end of the fuel injection nozzle 8 is connected to the fuel injection hole 23, and the oil inlet end of the fuel injection nozzle 8 is connected to the oil rail 5. The oil rail 5 is installed on the intake manifold 2. Further, at least two oil rail fixing brackets 6 are provided on the intake manifold 2, and a fixing plate 51 corresponding to the oil rail fixing bracket 6 is provided on the oil rail 5. The fixing plate 51 is locked with the corresponding oil rail fixing bracket 6 by screws, that is, a screw hole is provided on the oil rail fixing bracket 6, and a through hole for the screw to pass through is provided on the fixing plate 51. When the oil rail 5 is installed, the fixing plate 51 can be bent or the like according to the installation position of the oil rail 5.

[0024] In this embodiment, if Figure 1 As shown, there are four branch pipes 25, and the four branch pipes 25 are connected in parallel, and each branch pipe 25 corresponds to a cylinder body.

[0025] In this embodiment, if Figure 2 As shown, the axis line of the fuel injection hole 23 is parallel to the axis line of the jet hole 24. When the engine is stationary, the angle between the center line of the fuel injection hole 23 and the jet hole 24 and the outlet flange surface is 74°, and the distance between the center line of the fuel injection hole 23 and the jet hole 24 is 27 mm.

[0026] The working process of the utility model is as follows: when the engine is started, the ECU controls the valve of the jet nozzle 7 to close, and the jet nozzle 7 stops working. At the same time, the ECU controls the valve of the fuel injector 8 to open, and the fuel injector 8 works. After the fuel injector 8 injects jets into the mixing chamber 22, the oil and gas are mixed and enter the combustion chamber through the engine cylinder head intake duct for combustion. After combustion, the engine coolant is heated. When the engine coolant reaches a specified temperature, at this time, the ECU controls the valve of the fuel injector 8 to close, and the fuel injector 8 stops injecting fuel. The ECU controls the valve of the jet nozzle 7 to open, and the jet nozzle 7 sprays out combustible gas. The jet assembly sprays combustible gas into the mixing chamber 22, and the mixed gas enters the combustion chamber through the engine cylinder head intake duct for combustion.

[0027] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An intake system for a compressed natural gas engine, characterized in that: It includes an intake manifold, a throttle is installed at the intake end of the intake manifold, the throttle is connected to the air compression assembly, a pressure stabilizing chamber is provided in the intake manifold, an air outlet of the throttle is communicated with the pressure stabilizing chamber, a plurality of branch pipes are provided on the intake manifold, a mixing chamber is provided in the branch pipe, and the mixing chamber is communicated with the pressure stabilizing chamber, an injection hole and an oil injection hole are also opened on the branch pipe, the injection hole and the oil injection hole are both communicated with the mixing chamber, an injection assembly is installed in the injection hole, an oil injection assembly is installed in the oil injection hole, the injection assembly and the oil injection assembly are connected to an on-board computer, and the on-board computer controls the operation of the injection assembly and the oil injection assembly.

2. The air intake system for a compressed natural gas engine according to claim 1, characterized in that: The air injection assembly comprises an air rail and an air injection nozzle, the air outlet end of the air injection nozzle is connected to the air injection hole, the air inlet end of the air injection nozzle is connected to the air rail, and the air rail is installed on the intake manifold.

3. The air intake system for a compressed natural gas engine according to claim 2, characterized in that: At least two air rail fixing brackets are provided on the intake manifold, and fixing plates corresponding to the air rail fixing brackets are provided on the air rail, and the fixing plates are locked with the corresponding air rail fixing brackets by screws.

4. An intake system for a compressed natural gas engine according to any one of claims 1 to 3, characterized in that: The fuel injection assembly comprises a fuel rail and a fuel injection nozzle, the fuel outlet end of the fuel injection nozzle is connected to the fuel injection hole, the fuel inlet end of the fuel injection nozzle is connected to the fuel rail, and the fuel rail is installed on the intake manifold.

5. The air intake system for a compressed natural gas engine according to claim 4, characterized in that: At least two oil rail fixing brackets are provided on the intake manifold, and fixing plates corresponding to the oil rail fixing brackets are provided on the oil rail, and the fixing plates are locked with the corresponding oil rail fixing brackets by screws.

6. The air intake system for a compressed natural gas engine according to claim 1, characterized in that: There are four branch pipes, and the four branch pipes are connected in parallel.

7. The air intake system for a compressed natural gas engine according to claim 1, characterized in that: The axis center line of the oil injection hole is parallel to the axis center line of the air injection hole.

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