JPH03194121A - Diesel engine - Google Patents

Abstract

PURPOSE:To activate combustion in the latter period of combustion so as to improve combustibility by providing an air injector in the cylinder chamber of a diesel engine, thereby injecting high pressure air in the latter period of combustion. CONSTITUTION:In a diesel engine provided with a fuel injection nozzle 20 at a cylinder head 12, the cylinder head 12 is further provided with an air injector 21 placed by the side of the fuel injection nozzle 20. This air injector 21, which is an air pressure intensifying injector actuated by a solenoid valve 23, is connected to an air compressor 28 and an air tank 29 through air pressure piping 31. During the diesel engine operating time, high pressure air is injected from the air pressure intensifying injector 21 into a cylinder chamber in the latter period of combustion, so that combustion in its latter period is activated to accelerate combustion and reduce NOx contained in exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to diesel engines with accelerated combustion.

BACKGROUND TECHNOLOGY Normally, in a diesel engine, the injection timing is delayed,
Efforts have been made to reduce nitrogen oxides (NOx) contained in exhaust gas by promoting fuel-air mixing due to intake air turbulence and by atomizing fuel through high-pressure injection. The current situation is that it has reached its limit.

OBJECTS AND PROBLEMS OF THE INVENTION An object and problem of the present invention is to provide a diesel engine that reduces nitrogen oxides (NOX) contained in exhaust gas and improves exhaust gas.

Summary of the invention in terms of structure related to objects/problems: Contents of the claimed invention In relation to the above-mentioned objects/problems, the diesel engine of the present invention is characterized in that high-pressure air is injected into the cylinder chamber by an air injector in the late stage of combustion, The aim is to shorten the so-called combustion period by activating combustion in the latter stage of combustion and promoting combustion.

Description of Specific Examples Specified specific examples of the diesel engine of the present invention will be described below with reference to the drawings.

1 to 4 partially show an embodiment 10 of the day cell engine of the invention, which is embodied in a direct injection type.

The diesel engine 10 is a normal direct injection diesel engine with an air injector 21 and an air compressor 2.
8, air tank 29, control unit 30,
An ignition sensor (not shown) and an engine rotation sensor (not shown) are added, and the air injector 21
For this, an air booster injector operated by a solenoid valve 23 is used, which air booster injector 21 is arranged in the cylinder head 12 next to the fuel injection nozzle 20 in the same way as the fuel injection nozzle 20; Then, it was connected to the air compressor 28 and air tank 29 through pneumatic piping 31.

The air pressure booster injector 21 is assembled from an injector 22 and its solenoid valve 23, as shown schematically in FIGS. On the other hand, the solenoid valve 23 is assembled with the switching valve 26 and the pilot solenoid valve 27, and of course, they are
Assembled in one piece.

The nozzle 24 has a needle valve (not shown) that fits into a needle spindle bore (not shown) with a valve seat (not shown) and a spout (not shown). A spring (not shown) was fabricated to seat the needle valve in the Halke seat.

The booster cylinder 25 has a low pressure cylinder bore 33 and a high pressure cylinder bore 34 coaxially connected to each other.
A cylinder body 32 with a cylinder body 32 and its low pressure and high pressure cylinder bores 33, 34 correspondingly slidably fitted in a reciprocating manner, the low pressure cylinder bore 33 having a low pressure cylinder chamber 38 and an atmospheric pressure cylinder chamber 39. is assembled with a piston, rod, and ram 35 each forming a high-pressure cylinder chamber 40 in its high-pressure cylinder bore 34, and the discharge pressure of the air compressor 28 is 8 kg.
f/cM, so the ram 36 and piston rod 37 forming the piston rod ram 35 are
The area ratio is determined such that high-pressure air is injected from the nozzle 24 at a pressure of 80 kgf/c.

Further, a driving pressure boat 41 and a vent 42 are formed in the cylinder body 32 and are opened to correspond to the low pressure cylinder chamber 38 and the atmospheric pressure cylinder chamber 39, and the high pressure cylinder chamber 40 is connected to the high pressure cylinder chamber 40 at a predetermined position. An open air inlet port 43 and an air outlet boat 44 then open the high pressure cylinder bore 3 in position.
A vent 45 opened at each of the holes 4 and 4 is formed respectively.

Further, in the cylinder body 32, a driving pressure passage 46 connecting the low pressure side cylinder boat 60 of the switching valve 26 to the driving pressure boat 1-41 is connected to the air inlet boat 43, and a driving pressure passage 46 connects the low pressure side cylinder boat 60 of the switching valve 26 to the driving pressure boat 1-41. A low pressure side air passage 47 connecting the side cylinder boat 61 and a high pressure side air passage 48 connecting the air outlet boat 44 to the air reservoir (not shown) of the nozzle 24 are formed, respectively. Of course, a check valve 49 is arranged in the low pressure side air passage 47.

The piston rod ram 35 is formed with a spill communication passage 50 and a spill groove 51 that connect the vent 45 to the high pressure cylinder chamber 40 at the end of pressure increase.

The switching valve 26 includes a valve body 52 having a valve bore 53, and a pressure chamber 5 fitted into the valve bore 53 so as to be able to reciprocate and slide.
5 with a spring chamber 56 at the other end of the valve bore 53.
The valve body 52 is bolted to the cylinder body 32, and the pressure booster cylinder is 2
5 was integrally assembled.

The valve body 52 includes a pump boat 58, an exhaust boat 59, a low pressure side cylinder boat 60, and a high pressure side cylinder boat 61, which are opened in the valve bore 53 at predetermined positions, and further includes a pump boat 58, an exhaust boat 59, a low pressure side cylinder boat 60, and a high pressure side cylinder boat 61. The pressure chamber 55 is provided with a pneumatic reed boat 62 that opens into the valve bore 53 thereof. Of course, the pump boat 58 connects the air combination 1. with the pneumatic piping 31. connected to the tank 28 and the air tank 29, and
The exhaust port 59 is open to the atmosphere. on the other hand,
The low and high pressure side cylinder boats 60,61 correspond to the drive pressure port 41 and air inlet boat 43 of the booster cylinder 25 with the drive pressure passage 46 and the low pressure side air passage 47, as previously described. connected and furthermore,
The pneumatic lead boat 62 is connected to the pneumatic lead passage 6
3 is connected to the valve boat 73 of the pilot solenoid valve 27.

The spool 54 has a pair of lands 64.6 formed at a predetermined distance in the axial direction in relation to the boats.
5, the low-pressure side and high-pressure side cylinder boats 6061 are switched and connected to the pump boat 58 in response to sliding into the valve bore 53, and the low-pressure side cylinder boats 6061 are connected to the exhaust port 59. - Make the boat 60 intermittent.

The pilot solenoid valve 27 includes a valve body 66 having a valve bore 67, a spool 68 fitted into the valve bore 67 so as to be able to reciprocate and slide the spool 68 into the valve bore 67. The valve body 6G is manufactured by including an electromagnetic coil 69 to be moved and a return spring 70, and the valve body 6G is bolted to the valve body 52 of the switching valve 26.
integrated into the .

The valve body 66 also has a pump boat 7 opening into the valve bore 67 in position.
1, an exhaust port 72, and a valve boat 73. Of course, the pump boat 71 is connected to the air compressor 28 and air tank 29 by the pneumatic line 31, and the exhaust port 72 is
It is open to the atmosphere.

On the other hand, the valve boat 73, as mentioned above,
The pneumatic reed passage 63 is connected to the pneumatic reed boat 62 of the switching valve 26.

The spool 68 includes a land 74 and the valve
As the pump boat 7 is slid into the bore 67
1 and the valve boat 73 to the exhaust port 72.

The Nm coil 69 is connected to the control unit 3
It is electrically connected to the output side of 0, is excited by the current flowing from its control unit 30, and its return
The spool 68 is slid into the valve bore 67 against the spring 70, causing the spool 68 to act to switch the valve boat 73 between the pump boat 71 and the exhaust port 72.

The air compressor 28 is connected to the diesel engine 1
0, its air injector 21 and air
Compressed air (B kgf/cffl) can be supplied to the tank 29.

The control unit 30 electrically connects the input side to the ignition sensor and the engine rotation sensor, and
The output side is electrically connected to the electromagnetic coil 69 of the pilot electromagnetic valve 27, and the current flowing through the electromagnetic coil 69 is controlled according to the signals from the ignition sensor and the engine speed sensor. The switching valve 26 and the pressure boosting cylinder 25 are sequentially driven, and the high pressure air (80 kgf/cnT) is injected from the nozzle 24 into the cylinder chamber 15 in the late stage of combustion.
), and mainly consisted of an input and output circuit, a memory circuit, an arithmetic circuit, a control circuit, and a power supply circuit.

Further, in this diesel engine 10, 11 is a cylinder block, 13 is a piston, 14 is a liner, 16 is an intake port, 17 is an exhaust port, 18 is an intake valve, and 19 is an exhaust valve.

Next, the operation of the diesel engine 10 described above will be explained.

When the diesel engine 10 is operated, the air
The compressor 28 is driven, and its air tank 29 stores compressed air at a pressure of 8 kgf/c/.

On the other hand, the control unit 30 controls the current flowing through the electromagnetic coil 69 of the pilot electromagnetic valve 27 in response to signals from the ignition sensor and the engine rotation speed sensor.

First, a metering is carried out, in which case the current flowing through the electromagnetic coil 69 is cut off by the control unit 30, so that the spool 6 is connected to its return, as shown in FIG. In the pilot solenoid valve 27 , which is slid into its valve bore 67 by a spring 70 , the pump boat 71 is isolated from the valve boat 73 and at the same time the valve boat 7
3 is connected to its exhaust port 72.

As the pilot solenoid valve 27 is switched and operated, the air pressure in the pressure chamber 55 is released into the atmosphere from the exhaust port 72 of the pilot solenoid valve 27 via the air pressure lead passage 63. In the switching valve 26, its spool 54 is slid into its valve pore 53 by its return spring 57, as shown in FIG.
Boat 58 connects its high pressure side cylinder boat 61 and simultaneously its exhaust port 59 connects its low pressure side cylinder boat 61 to its high pressure side cylinder boat 61.
Each is connected to a boat 60.

Therefore, low-pressure air is supplied from the air tank 29 to the high-pressure cylinder chamber 40 through the pneumatic piping 31 and the low-pressure side air passage 47 by pushing open the check valve 49, and accordingly, the low-pressure cylinder chamber 38 The air pressure inside is released to the atmosphere from the exhaust port 59 of the switching valve 26 via the drive pressure passage 46, and preparations are made to inject high pressure air from the nozzle 24.

As shown in FIG. 4, in the latter half of the combustion period, the control unit 30 causes current to flow through the electromagnetic coil 69 for a certain period of time depending on the engine speed. is energized and slides its spool 68 into its valve bore 67 against its return spring 70, as shown in FIG.
The exhaust port 72 is closed and the valve boat 73 is connected to the pump boat 71.

1 2 In this way, the pilot solenoid valve 27 is operated to switch, so air pressure passes through the pneumatic pipe 31 and the pneumatic lead passage 63 to the pressure chamber 5 of the switching valve 26.
5, its spool 54 is thereby slid into its valve pore 53 against its return spring 57, its exhaust port 59 and high pressure side cylinder boat 61 are shut off, and at the same time , the pump
A boat 58 is connected to its low pressure side cylinder boat 60.

Therefore, low pressure air is supplied from the air tank 29 to the low pressure cylinder chamber 38 via the pneumatic piping 31 and the drive pressure passage 46, and the piston rod ram 3
5 is pushed down, and as a result, the low-pressure air that was previously metered and supplied to the high-pressure cylinder chamber 40 is compressed, becomes high-pressure air, and is discharged from the nozzle 24 through the high-pressure side air passage 48. It is injected into the cylinder chamber 15 to activate combustion in the late stage of combustion and promote combustion.

As a result, the combustion engine was shortened and the nitrogen oxides (NOx) contained in the exhaust gas was improved.

In the above-mentioned diesel engine 10, the air pressure increasing cylinder 21 has been described as having the area ratio of its ram 36 and its piston rod 37 determined so as to obtain high-pressure air with a pressure of 80 kgf/crfl. When the diesel engine 10 is equipped with a supercharger, the pressure is 150 to 1
The area ratio of the ram 36 and the piston rod 37 is determined so as to obtain high pressure air of 60 kgf/cffl.

Advantages and Benefits of the Invention As understood from the above, the diesel engine of the present invention is such that high-pressure air is injected into the cylinder chamber by the air injector in the late stage of combustion. Combustion is activated and promoted, thereby shortening the combustion period and reducing nitrogen oxides (No.) contained in exhaust gas, which is very useful for automobiles.

Relationship between the invention and specific examples 3 4 As mentioned above, from the specific examples of the present invention explained with reference to the drawings, it will be difficult for those with ordinary knowledge in the technical field to which this invention pertains to understand various designs. Modifications and changes can be easily made, and furthermore, the contents of this invention are essential to the establishment of the invention to accomplish the task of the invention, and the technical essence of the invention that is the nature of the invention. and can be easily replaced by a form that is objectively recognized as incorporating it.

[Brief explanation of drawings]

FIG. 1 is a schematic partial sectional view of a diesel engine of the present invention embodied as a direct injection type, and FIG. 2 shows the metering status of the air injector and solenoid valve used in the diesel engine shown in FIG. The schematic diagram, FIG. 3, is a schematic diagram of the air injector and the solenoid valve shown in FIG. 2 in the pressure feeding state, and
FIG. 4 is a diagram showing crank angle versus cylinder pressure and air injection. 21...Air injector (air pressure booster injector)
, 22... Injector, 23... Solenoid valve, 24...
... Nozzle, 25 ... Pressure increase cylinder, 26 ... Switching valve, 27 ... Pilot solenoid valve. 5

Claims (2)

[Claims] (1) A diesel engine in which high-pressure air is injected into the cylinder chamber by an air injector during the late stage of combustion. (2) The diesel engine according to claim 1, wherein the air injector is an air pressure booster injector operated by a solenoid valve.