Spark plug structure for high-horsepower natural gas engine

Abstract

The utility model relates to the field of natural gas engine parts, in particular to a spark plug structure for a high-horsepower natural gas engine, which comprises a combustion chamber, a gas inlet channel and a gas outlet channel which are connected with the combustion chamber, a plurality of spark plugs are arranged on the combustion chamber and positioned between the gas inlet channel and the gas outlet channel, and the gas inlet channel is communicated with the gas outlet channel. A spark plug sheath is arranged in the combustion chamber, the spark plugs are all installed in the spark plug sheath, the problem that a natural gas engine at the present stage is limited by the requirement for high conversion efficiency of a three-way catalyst is solved, an equivalent combustion mode is adopted, the heat insulation index of lower mixed gas is low, the detonation tendency and the heat transfer loss are high, and the combustion efficiency is high. And further improvement of the heat efficiency is very difficult.

Description

TECHNICAL FIELD

[0001] The utility model relates to natural gas engine parts field, concretely relates to a structure of spark plug for large horsepower natural gas engine. BACKGROUND

[0002] In recent years, under the driving of the "double carbon" strategy, the development goal of domestic natural gas engine focuses more on the improvement of thermal efficiency. At present, the piston compression ratio has been increased to 18~20, and deep Miller / Atkinson cycle and high proportion of cooled exhaust gas recirculation (EGR) are generally used to suppress knock; In addition, electrified accessories and low friction design are also used to reduce mechanical loss, so that the thermal efficiency has been gradually improved from the initial 38% to about 42%, however, the current natural gas engine is limited by the high conversion efficiency requirement of three-way catalyst, and all adopts equivalent combustion mode, and the adiabatic index of the mixture under this mode is low, the tendency of knock and the loss of heat transfer are high, so it is very difficult to further improve the thermal efficiency.

[0003] At present, a structure of spark plug for large horsepower natural gas engine is proposed to solve the above problems. INVENTION CONTENTS

[0004] The utility model discloses a structure of spark plug for large horsepower natural gas engine, which adopts three spark plug combustion chamber structure to solve the problem that the current natural gas engine is limited by the high conversion efficiency requirement of three-way catalyst, all adopts equivalent combustion mode, and the adiabatic index of the mixture is low, the tendency of knock and the loss of heat transfer are high, and it is very difficult to further improve the thermal efficiency.

[0005] To solve the above technical problems, the technical scheme adopted by the utility model is as follows:

[0006] A structure of spark plug for large horsepower natural gas engine, comprising a combustion chamber, an air inlet and an air outlet connected with the combustion chamber, a plurality of spark plugs arranged on the combustion chamber, the spark plugs located between the air inlet and the air outlet, a spark plug sheath arranged in the combustion chamber, and the plurality of spark plugs installed in the spark plug sheath.

[0007] Further limited, the spark plug has three, which are one main spark plug and two side spark plugs, the two side spark plugs are located on the left and right sides of the main spark plug respectively, and the distance from the two side spark plugs to the main spark plug is L1 and L2 respectively.

[0008] Further limited, the distance of L1 and L2 is 50mm.

[0009] Further limited, the diameter of the main spark plug is 12MM, the diameter of the two side spark plugs is 10MM, and the two side spark plugs are the same as the main spark plug.

[0010] The beneficial effects of the utility model relative to the present stage technology are:

[0011] Adopting three spark plug ignition can make the original NOx emission of the corresponding minimum fuel consumption rate decrease by about 90% compared with the pure equivalent combustion mode under the configuration, and can better improve the thermal efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 It is a partial sectional view of the utility model;

[0013] Fig. 2 It is a top view of the utility model;

[0014] Fig. 3 It is a data curve graph of NOx original emission and excess air coefficient φa.

[0015] The figure indicates that 1 is a combustion chamber, 2 is an air inlet, 3 is an air outlet, 4 is a main spark plug, 5 is a side spark plug, 6 is a spark plug sheath, and 7 is a cylinder head bottom surface. DETAILED DESCRIPTION

[0016] In order to make the technical personnel in the field can better understand the technical scheme of the utility model, the utility model technical scheme is further explained below in combination with the drawings and examples.

[0017] Examples

[0018] As Figs. 1-3 shown, a spark plug structure for a large horsepower natural gas engine includes a combustion chamber 1, an air inlet 2 and an air outlet 3 connected with the combustion chamber 1, three spark plugs are arranged on the combustion chamber 1, the three spark plugs are located between the air inlet 2 and the air outlet 3, the three spark plugs are a main spark plug 4 and two side spark plugs 5, the two side spark plugs 5 are located on the left and right sides of the main spark plug 4, the distance between the two side spark plugs 5 and the main spark plug 4 is L1 and L2, the distance between L1 and L2 is 50mm, a spark plug sheath is arranged in the combustion chamber 1, the main spark plug 4 and the two side spark plugs 5 are installed in the spark plug sheath 6, the diameter of the main spark plug 4 is 12MM, the diameter of the two side spark plugs 5 is 10MM, and the two side spark plugs 5 are the same as the main spark plug 4.

[0019] The peripheral ignition coil is also arranged on the test bench, the bottom surface 7 of the cylinder cover of the combustion chamber is provided with a conventional spark plug with a diameter of 12mm as a main spark plug, and two side spark plugs with a diameter of 10mm are additionally arranged on the left and right sides of the main spark plug, the two side spark plugs are separately developed to meet the space requirement of the ignition coil arrangement between the adjacent two cylinders, the structure of the two side spark plugs is consistent with that of the 12mm spark plug, and the charging time and corresponding ignition energy of the three spark plugs are calibrated and tested on the ignition performance test bench before the test, so that the ignition energy of each spark plug can reach (120±2) mJ under the test working condition.

[0020] In order to test the prototype using existing components, a low-resistance high-voltage lead is temporarily connected between the ignition coil and the spark plug, and an external control module and program are developed to realize independent control of the ignition enablement and ignition time of each spark plug. The preliminary test shows that the engine performance is optimal when the ignition time of the three spark plugs is set to be the same. In addition, the combustion chamber 1 is also compatible with the single spark plug ignition scheme, so that the comparative test can be conveniently carried out.

[0021] The three-spark plug ignition mode can significantly expand the lean combustion limit. Under the characteristic working condition of 2200r / min, the maximum φa (excess air coefficient) corresponding to stable combustion can reach 1.95, thereby reducing the minimum fuel consumption rate by 5g / (kW·h) compared with the single spark plug, and increasing the absolute value of thermal efficiency by about 1%. At this time, the φa is difficult to further increase and is mainly limited by the supercharging capacity. In addition, when the three-spark plug ignition is used to achieve the minimum fuel consumption rate, the original NOx emission can be reduced to 60×10-6, which is about 90% lower than that of the pure equivalent combustion mode under the same configuration.

[0022] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model

[0023] The structure of the spark plug for the large-horsepower natural gas engine provided by the utility model is described in detail above, and the description of the specific embodiments is only used to help understand the method and core idea of the utility model. It should be pointed out that for ordinary skilled persons in the technical field, without departing from the utility model, the utility model can be improved and modified in many ways, and these improvements and modifications also fall within the protection scope of the utility model claims.

Claims

1. A spark plug structure for a high power natural gas engine, comprising a combustion chamber (1), an air inlet channel (2) and an air outlet channel (3) connected to the combustion chamber (1), characterized in that: The combustion chamber (1) is provided with several spark plugs, the spark plugs are located between the air inlet (2) and the air outlet (3), the combustion chamber (1) is provided with a spark plug sheath (6), and the several spark plugs are installed in the spark plug sheath (6).

2. A structure of a spark plug for a large horsepower natural gas engine according to claim 1, characterized by: The spark plug has three, which are a main spark plug (4) and two side spark plugs (5), the two side spark plugs (5) are located on the left and right sides of the main spark plug (4) respectively, and the distances from the two side spark plugs (5) to the main spark plug (4) are L1 and L2 respectively.

3. A structure of a spark plug for a heavy-duty natural gas engine according to claim 2, characterized by: The distances of L1 and L2 are both 50mm.

4. A structure of a spark plug for a heavy-duty natural gas engine according to claim 2, characterized by: The diameter of the main spark plug (4) is 12MM, the diameters of the two side spark plugs (5) are both 10MM, and the structures of the two side spark plugs (5) are same as those of the main spark plug (4).

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