TW202004006A - Method and device for pre-assisting combustion diesel engine using hydrogen - Google Patents

Abstract

A method for pre-assisting combustion diesel engine using hydrogen, the method includes: atomizing a hydrogen gas to form a hydrogen spray; at a pre-determined angle, injecting a pre-determined amount of the hydrogen spray into an intake manifold through a gas nozzle before a top dead center of a compression stroke of a diesel engine; injecting the hydrogen spray into a cylinder by passing through the intake manifold; atomizing a diesel to form a diesel spray and injecting the diesel spray into the cylinder; pre-assisting combustion of the diesel spray by the hydrogen spray.

Description

Diesel engine hydrogen pre-combustion assisting method and device

The present invention relates to a diesel engine pre-combustion assisting method and device, and more particularly, to a diesel engine hydrogen pre-combustion assisting method and device.

Gasoline engines and diesel engines are commonly used in various vehicle vehicles or various industrial machines. Generally speaking, diesel engines are mostly used in heavy vehicles, ships and large industrial machinery based on their characteristics of large output power and low speed; while gasoline engines are mostly used in steam locomotives based on their small size, light weight and high speed. Small industrial machinery such as small propeller airplanes and lawn mowers. Based on the progress of engine technology and the demand for different output power, more and more small cars, commercial vehicles or recreational vehicles, etc., are equipped with diesel engines.

The operation of diesel engines can be roughly divided into two and four strokes. This refers to the four more common trips. The four strokes of diesel engine operation are roughly intake stroke, compression stroke, power stroke and exhaust stroke. In the intake stroke, the air in the intake manifold is drawn into the cylinder via the intake valve. The compression stroke is at the end of the intake stroke, and the piston moves upward from bottom dead center. Simultaneously with the upward displacement of the piston, the pressure and temperature begin to increase, and the air is compressed and heated above the ignition temperature. The power stroke is when the compression stroke is nearing the end, the diesel nozzle sprays the diesel in an atomized manner, and the compressed and heated air will ignite the atomized diesel. At this time, the pressure in the cylinder rises rapidly and pushes the piston downwards. This thrust becomes the force that causes the crankshaft to rotate. The exhaust stroke is after the end of the diesel combustion process. When the piston moves downwards and approaches the bottom dead center, the exhaust valve opens. When the piston is displaced upward again, the exhaust gas is discharged into the atmosphere through the exhaust valve and exhaust manifold.

In the above itinerary, whether the diesel can be completely burned depends on the output power of the engine. If the diesel cannot be completely burned, it will cause insufficient engine power, or even lack of air pollution or energy waste. Based on the above, it is still necessary to develop a diesel engine with high combustion efficiency and low pollution.

An object of the present invention is that during the running stroke of the diesel engine, before the top dead center of the compression stroke, the hydrogen spray is sprayed into the intake manifold by the gas nozzle, and then the hydrogen spray is sucked through the intake manifold to drive the hydrogen spray into the cylinder It burns together with diesel spray. In this way, through the flammable characteristics of the hydrogen spray, pre-combustion of the diesel spray in the cylinder is achieved to improve the combustion efficiency, and reduce exhaust emissions and improve engine power.

In one embodiment, the present invention discloses a hydrogen pre-combustion method for diesel engines, which is applied to a diesel engine. The diesel engine includes a cylinder and an intake manifold connected to the cylinder. The method for pre-combustion of hydrogen in a diesel engine includes: atomizing a hydrogen through a gas nozzle to form a hydrogen spray; before the diesel engine runs at a top dead center of a compression stroke, spraying the hydrogen spray at a preset angle and a preset spray Injection into the intake manifold; spraying the hydrogen spray into the cylinder through the intake manifold; atomizing a diesel through a diesel nozzle to form a diesel spray, and spraying the diesel spray into the cylinder; and burning through the hydrogen spray Pre-assisted diesel spray combustion in the cylinder.

According to the above-mentioned diesel engine hydrogen pre-combustion assisting method, wherein the preset angle is that the diesel engine runs between 70 degrees and 30 degrees before the dead center above the compression stroke.

According to the above-mentioned diesel engine hydrogen pre-combustion method, the gas nozzle sprays a hydrogen spray at an outlet speed of 35 meters per second (35 m/s) and a pressure difference of 10 inches of water (10 inch-H ₂ O).

According to the above-mentioned diesel engine hydrogen pre-combustion assisting method, wherein the calorific value of the preset injection volume of the hydrogen spray is 2% to 4% of the calorific value of the injection volume of the diesel engine in a single cycle.

According to the above hydrogen pre-combustion method for diesel engines, the cylinder may further include an intake valve. The intake valve communicates with the intake manifold when it is opened, and the hydrogen spray is injected into the cylinder through the opened intake valve.

In another embodiment, the present invention provides a hydrogen pre-combustion device for a diesel engine, which includes a cylinder, an intake manifold, an intake valve, a gas nozzle, a diesel nozzle, and a piston. The intake manifold communicates with the cylinder. The intake valve is provided between the intake manifold and the cylinder. The gas nozzle is arranged on the intake manifold, and one of the gas nozzles is directed toward the intake valve. The diesel nozzle communicates with the cylinder. The piston is displaced in the cylinder. Among them, before the diesel engine runs at the top dead center of a compression stroke, the gas nozzle sprays a hydrogen spray into the intake manifold at a preset angle and a preset injection volume, and sprays it through the open intake valve In the cylinder. The diesel nozzle sprays a diesel spray into the cylinder. The displacement of the piston compresses the air sucked in by the intake manifold, so that the hydrogen spray combustion assists the diesel spray combustion in advance.

According to the above hydrogen pre-combustion device for diesel engines, the cylinder may further include an exhaust valve and an exhaust manifold. The exhaust manifold communicates with the cylinder, and the exhaust valve is provided between the exhaust manifold and the cylinder.

According to the above-mentioned diesel engine hydrogen pre-combustion assisting device, one end of the gas nozzle forms an opening. One of the openings has a diameter ranging from 52 microns to 80 microns.

According to the above-mentioned diesel engine hydrogen pre-combustion device, the preset angle is that the diesel engine runs between 70 degrees and 30 degrees before the dead center above the compression stroke.

According to the above-mentioned diesel engine hydrogen pre-combustion device, the preset calorific value of the hydrogen spray is 2% to 4% of the calorific value of the diesel engine in a single cycle.

101‧‧‧ intake manifold

102‧‧‧Exhaust manifold

103‧‧‧ gas nozzle

104‧‧‧ Diesel nozzle

105‧‧‧ intake valve

106‧‧‧Exhaust valve

107‧‧‧ Piston

108‧‧‧Crankshaft

109‧‧‧Cylinder

A‧‧‧Opening

H‧‧‧hydrogen spray

F‧‧‧ Diesel spray

S101, S102, S103, S104, S105

Figure 1 is a schematic flow diagram of a hydrogen pre-combustion method for a diesel engine according to an embodiment of the invention; Figure 2 is a schematic structural diagram of a hydrogen pre-combustion device for a diesel engine according to another embodiment of the invention; and Figure 3 is a diagram A perspective view of the structure of the gas nozzle used in the hydrogen pre-combustion device of the diesel engine in FIG. 2 is shown.

In the following description, specific embodiments of the present invention will be described with reference to the accompanying drawings. Many practical details will be explained together in the following description. However, these practical details should not be used to limit the invention. That is, in some embodiments of the present invention, these practical details are unnecessary. In addition, for the sake of simplifying the drawings, some conventionally used structures and elements will be shown in a simple schematic manner in the drawings; and repeated elements may be indicated by the same number.

FIG. 1 is a schematic flowchart of a hydrogen pre-combustion method for a diesel engine according to an embodiment of the invention. The hydrogen pre-combustion method for diesel engines disclosed in FIG. 1 is applied to a diesel engine, which includes a cylinder and an intake manifold connected to the cylinder. The diesel engine hydrogen pre-combustion method includes the following steps: Step S101 is to atomize a hydrogen through a gas nozzle to form a hydrogen spray; Step S102 is to spray the hydrogen gas before the diesel engine runs at a top dead center of a compression stroke A preset angle and a preset injection volume are injected into the intake manifold; step S103 is to spray hydrogen into the cylinder through the intake manifold; step S104 is to atomize a diesel through a diesel nozzle to form a diesel spray, And spray the diesel spray into the cylinder; step S105 is to assist the diesel spray combustion in the cylinder in advance through the hydrogen spray combustion.

In order to make the pre-combustion effect of hydrogen spray on diesel spray the best, select the better value of the operating parameters. Specifically, in the above hydrogen pre-combustion method for diesel engines, the preset angle is that the diesel engine runs between 70 degrees and 30 degrees before the dead center above the compression stroke. In the above-mentioned diesel engine hydrogen pre-combustion method, the gas nozzle sprays a hydrogen spray at an outlet speed of 35 meters per second (35 m/s) and a pressure difference of 10 inches of water (10 inch-H ₂ O). In the above diesel engine hydrogen pre-combustion method, the preset calorific value of the hydrogen spray is set to be 2% to 4% of the calorific value of the diesel engine's injection volume in a single cycle.

FIG. 2 is a schematic structural diagram of a hydrogen pre-combustion device for a diesel engine according to another embodiment of the present invention. As can be seen from FIG. 2, the hydrogen pre-combustion device of the diesel engine includes a cylinder 109, an intake manifold 101, an exhaust manifold 102, an intake valve 105, an exhaust valve 106, a gas nozzle 103, a diesel The nozzle 104, a piston 107 and a crankshaft 108. The intake manifold 101 and the exhaust manifold 102 communicate with the cylinder 109. An intake valve 105 is provided between the intake manifold 101 and the cylinder 109, and an exhaust valve 106 is provided between the exhaust manifold 102 and the cylinder 109. The gas nozzle 103 is provided on the intake manifold 101 with its jet direction facing the intake valve 105. The diesel nozzle 104 directly communicates with the cylinder 109.

Here, referring to the second figure, the operation of the hydrogen pre-combustion device of the diesel engine. This section first describes the running stroke of the diesel engine. Intake stroke: The exhaust valve 106 closes and the intake valve 105 opens. When the piston 107 is displaced from the top dead center to the bottom dead center, the air in the intake manifold 101 is drawn into the cylinder 109 via the intake valve 105. At this time, fuel (ie diesel) has not yet entered the cylinder 109. Compression stroke: After the end of the intake stroke, when the piston 107 starts to move upward from the bottom dead center, the intake valve 105 closes and stops intake. As the piston 107 moves upward, the air is compressed and the pressure and temperature begin to increase. During the compression stroke, the air must be compressed and heated until it reaches above the diesel ignition temperature. Power stroke: When the piston 107 moves upwards to near the top dead center, the compression stroke is near the end, the diesel nozzle 104 atomizes the diesel to form a diesel spray F, and sprays it into the cylinder 109, then the compressed and heated air ignites the diesel Spray F. When the pressure in the cylinder 109 rises rapidly and pushes the piston 107 downwards, this pushing force forms a force that causes the crankshaft 108 to rotate. Exhaust stroke: After the combustion process of the diesel spray F is completed, when the piston 107 moves downward to near bottom dead center, the exhaust valve 106 opens. When the piston 107 is displaced upward again, the exhaust gas generated by the combustion of the diesel spray F is discharged into the atmosphere through the exhaust valve 106 and the exhaust manifold 102 communicating therewith. At this point, a single cycle of diesel engine operation is completed. In the present invention, the gas nozzle 103 provided on the intake manifold 101 atomizes hydrogen to form a hydrogen spray H, and sprays the hydrogen H before the dead point above the compression stroke (that is, before the piston 107 moves to the top dead point). It is injected into the intake manifold 101 and enters the cylinder through the opened intake valve 105. Subsequently, the diesel nozzle 104 also sprays the diesel spray F into the cylinder 109 to start combustion. Since the hydrogen spray H is highly flammable, the combustion of the diesel spray F can be assisted in advance, so that the combustion of the diesel spray F is more complete.

FIG. 3 is a perspective view showing the structure of the gas nozzle 103 used in the hydrogen pre-combustion device of the diesel engine in FIG. 2. In one embodiment, the gas nozzle 103 in the present invention uses an industrial gas furnace nozzle that has passed through a three-stage pressure reducing valve in advance. It has a simpler structure than the conventional generation of hydrogen spray H, and the cost is cheaper. Moreover, the diameter of the opening A at one end of the gas nozzle 103 may range from 52 microns to 80 microns. By this, a hydrogen spray H with an outlet speed of 35 meters per second (35 m/s) and a pressure difference of 10 inches of water (10 inches-H ₂ O) can be sprayed. The material of the gas nozzle 103 may be copper or other possible materials. Please refer to FIG. 2, the gas nozzle 103 sprays the hydrogen spray H into the cylinder 109 between 70 degrees and 30 degrees before the top dead center of the compression stroke to obtain a better auxiliary combustion effect. The pre-combustion effect of the present invention on the diesel spray F through the gas nozzle 103 with a special structure at a specific time point, in conjunction with the preset spray volume and the preset angle of the selected hydrogen spray H, will be continuously described.

The present invention selects hydrogen as the pre-combustion aid for diesel combustion, which is based on the material characteristics of hydrogen. For example, during the combustion process of hydrogen, only water and nitrogen oxides are generated, but no carbon monoxide (CO), carbon dioxide (CO ₂ ), hydrocarbons (HC), nitrogen oxides (NO _X ), black smoke And environmentally harmful pollutants such as dust particles. Furthermore, hydrogen is a highly flammable gas, and its rapid combustion is conducive to accelerating the complete combustion of diesel.

Changes in NO _X emission concentration: Under different loads of various engine speeds, NO _X concentration values were observed to increase slightly. The possible reason is that hydrogen has the characteristics of strong diffusibility, high flammability, high calorific value, etc., so it has a significant pre-combustion effect on the diesel spray F in the cylinder 109, so the combustion speed in the cylinder is accelerated.

Changes in HC emission concentration: Under different loads of various engine speeds, a decrease in HC emission concentration is observed. This is based on the excellent flammability of hydrogen, which shortens the time for the end of combustion of diesel spray F, so it can effectively reduce HC Of emissions.

Changes in CO emission concentration: Under different loads of various engine speeds, a decrease in CO emission concentration was observed. This is based on the preset injection quantity of the hydrogen spray H selected in the present invention, which has a significant pre-combustion effect on the diesel spray F, makes its combustion more complete, and shortens the end time of the diesel spray F combustion.

Changes in CO ₂ emission concentration: It was observed that the CO ₂ emission concentration gradually decreased as the preset spray amount of hydrogen spray H increased. This is based on the preset injection quantity of the hydrogen spray H selected in the present invention, which has a significant pre-combustion effect on the diesel spray F, makes its combustion more complete, and shortens the end time of the diesel spray F combustion.

Black smoke emission concentration change: After adding the selected preset amount of hydrogen spray H to assist diesel fuel spray F, the black smoke emission concentration can be observed to decrease. The main reason is that the ignition point of hydrogen is low and the combustion rate is quite high, which helps the combustion of diesel spray F to be more complete at all engine speeds and loads, and to achieve the pre-combustion effect of auxiliary diesel spray F, which reduces the concentration of black smoke. .

Engine torque change: At the same time, when using the preset amount of hydrogen spray H as a combustion aid for diesel spray F combustion, the temperature at which the peak ignition pressure is generated can be advanced by 3 to 5 degrees, and the engine torque can be increased by about 5%. This also indicates that the use of hydrogen spray H for pre-combustion has a significant benefit for the complete combustion of diesel spray F.

Changes in engine fuel consumption: E-BSFC is used to evaluate engine fuel consumption. The unit of E-BSFC is mainly the fuel calorific value required to produce a kilowatt of power for one hour. When pre-combustion is used for the combustion of diesel spray F with hydrogen spray H at a preset injection volume, E-BSFC can be reduced by 15% to 30%, which shows an increase in engine combustion efficiency, which means a reduction in fuel consumption.

In summary, although a slight increase in NO _X emission concentration was observed, the emission concentrations of HC, CO, CO ₂ and E-BSFC all showed a downward trend. Furthermore, an increase in engine torque was also observed. Therefore, the hydrogen spray H does have a significant pre-combustion effect on the combustion of the diesel spray F. That is to say, through the diesel engine hydrogen pre-combustion assisting method and device of the present invention, not only can the fuel consumption be reduced, the engine torque can be improved, but also the environmental protection effect can be achieved.

Although the present invention has been disclosed as above in the embodiments, it is not intended to limit the present invention. Any person who is familiar with this art can make various changes and modifications within the spirit and scope of the present invention, so the protection of the present invention The scope shall be determined by the scope of the attached patent application.

S101, S102, S103, S104, S105

Claims (10)

A diesel engine hydrogen pre-combustion assisting method, which is applied to a diesel engine, and the diesel engine includes a cylinder and an intake manifold connected to the cylinder, the diesel engine hydrogen pre-combustion assisting method includes: applying a hydrogen gas through a gas nozzle Atomization forms a hydrogen spray; before the diesel engine runs at one of the top strokes of a compression stroke, the hydrogen spray is sprayed into the intake manifold at a preset angle and a preset spray volume; the hydrogen The spray is sprayed into the cylinder through the intake manifold; a diesel is atomized through a diesel nozzle to form a diesel spray, and the diesel spray is sprayed into the cylinder; and the hydrogen spray is burnt to assist the cylinder in advance The diesel spray burns. The hydrogen pre-combustion method for a diesel engine as described in item 1 of the patent application range, wherein the preset angle is that the diesel engine runs between 70 degrees and 30 degrees before the top dead center of the compression stroke. The hydrogen pre-combustion method for diesel engines as described in item 1 of the patent application scope, wherein the gas nozzle has an outlet speed of 35 meters per second (35m/s) and one of 10 inches of water (10inch-H ₂ O) The hydrogen pressure sprayed out of the pressure difference. The diesel engine hydrogen pre-combustion method as described in item 1 of the patent application range, wherein the heat value of the preset injection volume of the hydrogen spray is the heat value of the injection volume of the diesel spray of the diesel engine in a single cycle 2%~4%. The hydrogen pre-combustion method for a diesel engine as described in item 1 of the patent application scope, wherein the cylinder includes an intake valve that communicates with the intake manifold when opened, and the hydrogen spray passes through the opened intake valve Spray into the cylinder. A diesel engine hydrogen pre-combustion device, comprising: a cylinder; an intake manifold, which communicates with the cylinder; an intake valve, which is arranged between the intake manifold and the cylinder; and a gas nozzle, which is arranged in On the intake manifold, one of the gas nozzles is directed toward the intake valve; a diesel nozzle, which communicates with the cylinder; and a piston, which is displaced within the cylinder; wherein, the diesel engine is operated on a compression Before the top dead center of one of the strokes, the gas nozzle sprays a hydrogen spray into the intake manifold at a preset angle and a preset injection volume, and into the cylinder through the open intake valve, the diesel The nozzle sprays a diesel spray into the cylinder, and the displacement of the piston compresses the air sucked in by the intake manifold, so that the combustion of the hydrogen spray assists the combustion of the diesel spray in advance. The hydrogen pre-combustion device for a diesel engine as described in item 6 of the patent scope, wherein the cylinder further includes an exhaust valve and an exhaust manifold, the exhaust manifold communicates with the cylinder, and the exhaust valve is disposed in the row Between the gas manifold and the cylinder. As described in Item 6 of the patent application scope, a hydrogen pre-combustion device for a diesel engine, wherein one end of the gas nozzle forms an opening, and a diameter of the opening ranges from 52 microns to 80 microns. The hydrogen pre-combustion device for a diesel engine as described in item 6 of the patent application range, wherein the preset angle is that the diesel engine runs between 70 degrees and 30 degrees before the top dead center of the compression stroke. The diesel engine hydrogen pre-combustion device as described in item 6 of the patent application range, wherein the calorific value of the preset injection volume of the hydrogen spray is the calorific value of the injection volume of the diesel spray of the diesel engine in a single cycle 2%~4%.

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