CN107762697B

CN107762697B - Variable fuel injection timing adjusting device of diesel engine

Info

Publication number: CN107762697B
Application number: CN201710938613.3A
Authority: CN
Inventors: 于恩程; 高益多; 邵煜; 沈建华
Original assignee: CSSC Marine Power Co Ltd
Current assignee: CSSC Marine Power Zhenjiang Co Ltd
Priority date: 2017-10-11
Filing date: 2017-10-11
Publication date: 2020-04-24
Anticipated expiration: 2037-10-11
Also published as: CN107762697A

Abstract

The invention discloses a variable oil injection timing adjusting device of a diesel engine, which comprises a mounting frame, a helical gear connecting shaft, an adjusting inner gear ring, a timing gear, a hydraulic actuating mechanism, a controller and an adjusting inner gear ring moving scale, wherein the mounting frame is positioned at the top of a diesel engine frame, one end of the helical gear connecting shaft is supported in one end of the mounting frame, one end of a cam shaft is fixedly connected with one end of the helical gear connecting shaft, the other end of the helical gear connecting shaft is meshed with the adjusting inner gear ring, one end of the adjusting inner gear ring is supported in one end of the mounting frame, and the timing gear is fixed on the. One end of a piston rod of the hydraulic actuating mechanism is fixedly connected with the other end of the adjusting inner gear ring through a plurality of adjusting screws, two cavities of the hydraulic cylinder barrel are respectively connected with the electromagnetic directional valve, signal wires at two ends of the electromagnetic directional valve are respectively connected with the controller, and the adjusting inner gear ring moving scale is arranged outside one end of the actuating mechanism. The invention has the advantages of high integration, compact structure, safety and reliability, can carry out active adjustment under all working conditions and is convenient to be additionally arranged on a diesel engine.

Description

Variable fuel injection timing adjusting device of diesel engine

Technical Field

The invention relates to a diesel engine-driven oil injection adjusting device, in particular to a variable oil injection timing adjusting device suitable for a marine high-power medium-speed diesel engine, and belongs to the technical field of diesel engines.

Background

With the stricter emission regulations of the international maritime organization and the fierce competition of the marine diesel engine industry, the requirements of domestic and foreign markets on improving the performance of a marine high-power (more than or equal to 1000 kW) medium-speed (300-1000 r/min) diesel engine and reducing the emission pollution are higher and higher. According to the principle of the diesel engine, the fuel injection timing of the diesel engine accurately controls the starting of the fuel pump through a chain wheel, a timing gear, a cam shaft, a cam lamp and other transmission parts, and the fuel injection and combustion of the engine are ensured according to a certain rule. Before the diesel engine leaves a factory, a manufacturer can calculate and select an optimal oil injection timing angle by integrating combustion performance, emission requirements and the like, and further lock the cam angle through a timing process of a rack. However, the generated fuel injection timing is a fixed value, is a compromise choice under the full-working-condition operation of the diesel engine, and cannot meet the performance requirement of the diesel engine under the full-working condition, so that the effective power of the diesel engine is reduced under the partial-load working condition, the emission performance is poor, and the requirements of relevant regulations cannot be met.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a variable fuel injection timing adjusting device (VIT) of a diesel engine, which enables the diesel engine to automatically adjust fuel injection timing along with load change, ensures that the diesel engine achieves optimal performance under different working conditions and reduces emission pollution.

The invention is realized by the following technical scheme:

a variable oil injection timing adjusting device of a diesel engine comprises a mounting frame, a helical gear connecting shaft, an adjusting inner gear ring, a timing gear, a hydraulic actuating mechanism, a controller and an adjusting inner gear ring moving scale, wherein the mounting frame is positioned at the top of a diesel engine frame and positioned outside one end of a cam shaft; the hydraulic actuating mechanism comprises a hydraulic cylinder barrel, a piston rod and a piston, one end of the hydraulic cylinder barrel is fixed in the other end of the mounting frame, the piston is fixed on the middle part of the piston rod, one end of the piston rod is fixedly connected with the other end of the adjusting inner gear ring through a plurality of adjusting screws, two cavities of the hydraulic cylinder barrel are respectively connected with the electromagnetic directional valve through hydraulic oil pipes, and signal wires at two ends of the electromagnetic directional valve are respectively connected with the controller; the adjusting inner gear ring moving scale is arranged outside one end of the executing mechanism.

Furthermore, a conical table with a cavity is extended from the inner side of one end of the mounting frame towards the direction of the hydraulic actuating mechanism, a connecting column is radially extended from one end of the helical tooth connecting shaft, and the connecting column is supported in the small end of the conical table through a first shaft sleeve.

Furthermore, one end of the hydraulic cylinder barrel is axially provided with a bearing box body, one end of the piston rod radially extends out of a supporting column with the diameter larger than that of the piston rod, and the supporting column is supported in one end of the bearing box body through a third shaft sleeve.

Furthermore, a support column flange extends out of one end of the support column in the radial direction, an inner gear ring flange extends out of the other end of the adjusting inner gear ring in the radial direction, a plurality of kidney-shaped grooves are uniformly distributed in the support column flange in the radial direction, and adjusting screws penetrate through the kidney-shaped grooves and are screwed into the inner gear ring flange, so that the piston rod and the adjusting inner gear ring are fixedly connected into a whole.

Furthermore, the adjusting inner gear ring moving scale is horizontally fixed on a mounting plate, and one end of the mounting plate is fixed at the other end of the hydraulic cylinder barrel; the other end of the piston rod extends out of the other end of the hydraulic cylinder barrel, one end of the horizontal pointer is fixed on the end head of the other end of the piston rod, and the other end of the horizontal pointer points to the scale marks.

Further, the helical angle β =8 ° -15 ° of the helical tooth head.

The invention adopts a structure that one end of a cam shaft is fixedly connected with a helical gear connecting shaft, a helical gear head of the helical gear connecting shaft is meshed with an adjusting inner gear ring, a piston rod of a hydraulic actuating mechanism is connected with the adjusting inner gear ring, after a controller receives a load change signal and a VIT position signal transmitted by a diesel engine, the controller compares the load change signal and the VIT position signal with corresponding set values, if deviation exists (namely an oil injection angle is not advanced), a corresponding command is sent out, high-pressure oil pushes a piston to move towards a moving scale of the adjusting inner gear ring through reversing of a reversing valve, the adjusting inner gear ring is pulled by the piston rod to move towards the moving scale of the adjusting inner gear ring, the helical gear head is forced to rotate clockwise, and then a cam on the cam shaft is driven to rotate clockwise by the same angle, so that the oil injector injects oil into a cylinder of, the combustion is more sufficient and complete, so that the after-combustion is reduced, the exhaust temperature is reduced, the average effective power is improved, and the economic performance of the diesel engine is correspondingly improved. The cam is highly integrated, compact in structure, safe and reliable, can be actively regulated under all working conditions, is convenient to add on a diesel engine, is suitable for clockwise or anticlockwise rotation of the cam, can effectively reduce the emission of NOx (nitrogen oxide), improves the operation working condition, reduces the oil consumption, improves the performance indexes such as maximum explosion pressure and the like, and greatly improves the economic performance of the diesel engine.

Advantages and features of the present invention will be illustrated and explained by the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of the advanced fuel injection operation of the present invention;

FIG. 2 is an enlarged sectional view A-A of FIG. 1;

FIG. 3 is a schematic view of the late injection operation of the present invention;

FIG. 4 is an enlarged sectional view B-B of FIG. 3;

fig. 5 is an enlarged sectional view of C-C of fig. 3.

Detailed Description

The invention will be further explained below with reference to the accompanying drawings and an embodiment of a medium speed diesel engine for a ship.

As shown in fig. 1, the invention comprises a mounting frame 1, a helical gear coupling shaft 2, an adjusting inner gear ring 3, a timing gear 4, a hydraulic actuator 5, a controller 6 and an adjusting inner gear ring moving scale 7, wherein the mounting frame 1 is positioned at the top of a diesel engine frame and is positioned outside one end of a cam shaft 10, and the mounting frame 1 of the embodiment is cast with the diesel engine frame into a whole or can be independently installed on the top of the diesel engine frame.

A conical table 11 with a cavity is extended from the inner side of the left end of the mounting frame 1 towards the direction of the hydraulic actuating mechanism 5, a connecting column 21 is radially extended from the left end of the helical tooth connecting shaft 2, and the connecting column 21 is supported in the small end head of the conical table 11 through a first shaft sleeve 211. A camshaft flange 101 at the right end of the camshaft 10 is fixedly connected with a connecting column 21 at the left end of the helical tooth connecting shaft 2 through a fastening screw, a helical tooth head 22 at the right end of the helical tooth connecting shaft 2 is meshed with the adjusting inner gear ring 3, the left end of the adjusting inner gear ring 3 is supported in a conical table 11 at the left end of the mounting frame 1 through a second shaft sleeve 31, and the timing gear 4 is fixed at the right end of the adjusting inner gear ring 3.

The hydraulic actuator 5 comprises a hydraulic cylinder 51, a piston rod 52 and a piston 53, wherein a bearing box 511 is arranged at the left end of the hydraulic cylinder 51, a supporting column 521 with a diameter larger than that of the piston rod 52 radially extends out of the left end of the piston rod 52, and the supporting column 521 is supported in the left end of the bearing box 511 through a third shaft sleeve 54. The piston 53 is fixed on the middle part of the piston rod 52, the two cavities of the hydraulic cylinder 51 are respectively connected with the electromagnetic directional valve 55 through the hydraulic oil pipe 512, and the signal wires 551 at the two ends of the electromagnetic directional valve 55 are respectively connected with the controller 6. A support column flange 522 extends from the left end of the support column 521 in the radial direction, and an inner gear ring flange 311 extends from the right end of the adjusting inner gear ring 3 in the radial direction, so that in order to adjust the relative angle between the cam shaft 10 and the cam 102, as shown in fig. 5, 4 waist-shaped grooves 523 are uniformly distributed in the support column flange 522 in the radial direction, and the adjusting screws 8 penetrate through the waist-shaped grooves 523 and are screwed into the inner gear ring flange 31, so that the piston rod 52 and the adjusting inner.

The adjusting inner gear ring moving scale 7 is horizontally fixed on a mounting plate 71, and the left end of the mounting plate 71 is fixed on the right end of the hydraulic cylinder 51; the right end of the piston rod 52 extends out of the right end of the hydraulic cylinder 51, the left end of the horizontal pointer 72 is fixed on the end head of the right end of the piston rod 52, and the right end points to the scale marks. When the piston rod 52 moves, the horizontal pointer 72 moves along with the piston rod, and the right end of the horizontal pointer indicates the stroke of the piston rod 52, namely the piston rod 52 pushes the adjusting ring gear 3 to move, so that the helical tooth head 22 engaged with the adjusting ring gear 3 is pushed to rotate, and the purpose of adjusting the angle of the cam 102 on the camshaft 10 is achieved.

In order to ensure that the helical tooth connecting shaft 2 can be well pushed to rotate when the inner gear ring 3 is adjusted to move forwards and backwards, the inner gear ring 3 and the helical tooth head 22 cannot be self-locked, so that the helical angle β = 8-15 degrees, the helical angle β cannot be too small, and otherwise, the inner gear ring 3 cannot be self-locked, and cannot be too large, and the rotation angle of the inner gear ring 3 cannot be accurately adjusted.

When the inner gear ring 3 and the helical tooth head 22 are adjusted to be meshed, the inner gear ring is subjected to alternating load effects such as torsion and bending, certain extrusion and abrasion exist, the helical tooth connecting shaft 2 is made of alloy steel material 20GrMnTi with high strength, the surface of the helical tooth is subjected to high-frequency induction quenching and carbonitriding chemical heat treatment, and the tooth surface hardness is HRC 58-62. The adjusting inner gear ring 3 is made of 40Cr materials, high-frequency induction quenching and carbonitriding chemical heat treatment are also carried out on the surface of the helical teeth, the tooth surface hardness is HRC 52-56, and different materials and hardness among meshing parts can prevent the adjusting inner gear ring 3 and the helical tooth heads 22 from being seized.

The working process of the invention is as follows:

as shown in fig. 1 and 2, when the diesel engine is operated from a low load to a high load, the fuel injection amount per cycle increases with the increase of the load, but the detonation pressure does not reach the rated detonation pressure value, and the generated effective power is reduced. In order to increase the detonation pressure to improve the effective power and reduce the after-combustion, the advance angle of the oil injection needs to be gradually increased to meet the requirement. After receiving the diesel engine load change signal and the VIT position signal transmitted by the sensor, the controller 6 compares the signals with the corresponding set values of the controller 6, if there is a deviation (i.e. the oil injection angle is not advanced), a corresponding command is sent, the electromagnetic coils at the two ends of the electromagnetic directional valve 55 are powered on and powered off through the signal line 551, the spool of the electromagnetic directional valve 55 is reversed to the left, the high-pressure hydraulic oil flows from the left chamber of the hydraulic cylinder body 51 through the hydraulic oil pipe 512 in the direction indicated by the hollow arrow, the low-pressure hydraulic oil in the right chamber flows back to the oil tank, the piston rod 52 is pushed to move right, the adjusting inner gear ring 3 is driven to move right through the adjusting screw 8, the helical tooth head 22 of the helical tooth connecting shaft 2 is forced to rotate clockwise by an omega angle, the cam 102 on the camshaft 10 is driven to rotate clockwise by the omega angle shown in fig, therefore, the preparation time of the fuel in the cylinder is prolonged, the quality of combustible mixed gas is improved, the combustion is more sufficient and complete, the after-combustion is reduced, the exhaust temperature is reduced, the average effective power is improved, and the economic performance of the diesel engine is correspondingly improved.

As shown in FIGS. 3 and 4, when the diesel engine starts to operate at a high load (generally higher than 80% load), the mechanical load of the diesel engine is high, and the generated detonation pressure and NO are high_XThe fuel injection advance angle is gradually reduced to meet the requirement. As shown in fig. 3, the controller 6 sends out a corresponding command, the valve core of the electromagnetic directional valve 55 is reversed to the right position, the high-pressure hydraulic oil flows from the right chamber of the hydraulic cylinder 51 through the hydraulic oil pipe 512 in the direction indicated by the hollow arrow, the low-pressure hydraulic oil in the left chamber flows back to the oil tank, the piston rod 52 is pushed to move left, the adjusting inner gear ring 3 is driven to move left through the adjusting screw 8, the helical tooth head 22 of the helical tooth connecting shaft 2 is forced to rotate counterclockwise by an angle theta, the cam 102 on the camshaft 10 is driven to rotate counterclockwise by an angle theta shown in fig. 4, and the fuel injector injects oil into the cylinder at the angle theta delayed, so that the mechanical overload is prevented, the detonation pressure is reduced_XAnd (4) discharging.

Considering performance requirements of the marine medium-speed diesel engine under different working conditions, the VIT device can be used for advancing oil injection by 0-8 degrees or delaying the oil injection by 0-8 degrees, and specific adjusting values are jointly controlled through the helical angle β of the helical teeth of the helical tooth connecting shaft 2, the diameter of the addendum circle of the helical teeth and the stroke of the inner gear ring 3.

After the assembly is completed, the original angle value of the cam 102 corresponding to the initial state of the VIT at the scale of 0 needs to be recorded before the factory is delivered. After the diesel engine is operated for a period of time, the calibration can be performed according to the recorded original angle value and the angle value after the cam 102 is changed. The checking process is as follows: after the diesel engine is stopped, after the VIT returns to the '0 scale' through visual inspection, a standard measuring tool is used for detecting the corresponding angle of the cam 102, the measured value is compared with a factory record value, if deviation occurs, the '0 scale' of the VIT is kept unchanged, the adjusting screw 8 is loosened, the connection between the adjusting inner gear ring 3 and the supporting column 521 at the left end of the piston rod 52 is disconnected, then the cam shaft 10 is rotated, the cam 102 is rotated back to the factory record value again, then the adjusting screw 4 is screwed again, and the method can be used for periodically detecting the VIT.

If the helical gear of the helical gear coupling shaft 2 is rotated to the left opposite to that shown in fig. 1 and the rest of the structure is not changed, the VIT control mode is also opposite. All technical solutions formed by adopting such equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims

1. The utility model provides a variable oil spout adjusting device in right time of diesel engine which characterized in that: the mounting frame is positioned at the top of a diesel engine frame and positioned outside one end of a cam shaft, one end of the helical gear connecting shaft is supported in one end of the mounting frame through a first shaft sleeve, one end of the cam shaft is fixedly connected with one end of the helical gear connecting shaft, a helical tooth head at the other end of the helical gear connecting shaft is meshed with the adjusting inner gear ring, one end of the adjusting inner gear ring is supported in one end of the mounting frame through a second shaft sleeve, and the timing gear is fixed at the other end of the adjusting inner gear ring; the hydraulic actuating mechanism comprises a hydraulic cylinder barrel, a piston rod and a piston, one end of the hydraulic cylinder barrel is fixed in the other end of the mounting frame, the piston is fixed on the middle part of the piston rod, one end of the piston rod is fixedly connected with the other end of the adjusting inner gear ring through a plurality of adjusting screws, two cavities of the hydraulic cylinder barrel are respectively connected with the electromagnetic directional valve through hydraulic oil pipes, and signal wires at two ends of the electromagnetic directional valve are respectively connected with the controller; the adjusting inner gear ring moving scale is arranged outside one end of the executing mechanism; after the controller receives a load change signal and a VIT position signal transmitted by the diesel engine, the load change signal and the VIT position signal are compared with corresponding set values, if deviation exists, a corresponding instruction is sent, the direction is changed through a reversing valve, the high-pressure oil pushes a piston to move towards the direction of a moving scale of the adjusting inner gear ring, the piston rod pulls the adjusting inner gear ring to move towards the direction of the moving scale of the adjusting inner gear ring, the helical tooth head is forced to rotate clockwise, and then a cam on a cam shaft is driven to rotate clockwise by the same angle.

2. The variable injection timing adjusting apparatus for a diesel engine according to claim 1, wherein: a conical table with a cavity is extended towards the direction of the hydraulic actuating mechanism from the inner side of one end of the mounting frame, a connecting column is radially extended from one end of the helical tooth connecting shaft, and the connecting column is supported in the small end head of the conical table through a first shaft sleeve.

3. The variable injection timing adjusting apparatus for a diesel engine according to claim 1, wherein: one end of the hydraulic cylinder barrel axially extends out of the bearing box body, one end of the piston rod radially extends out of the supporting column with the diameter larger than that of the piston rod, and the supporting column is supported in one end of the bearing box body through a third shaft sleeve.

4. The variable injection timing adjusting apparatus for a diesel engine according to claim 3, wherein: and a support column flange extends from one end of the support column in the radial direction, an inner gear ring flange extends from the other end of the adjusting inner gear ring in the radial direction, a plurality of kidney-shaped grooves are uniformly distributed on the support column flange in the radial direction, and an adjusting screw penetrates through the kidney-shaped grooves and is screwed into the inner gear ring flange, so that the piston rod and the adjusting inner gear ring are fixedly connected into.

5. The variable injection timing adjusting apparatus for a diesel engine according to claim 1, wherein: the adjusting inner gear ring moving scale is horizontally fixed on a mounting plate, and one end of the mounting plate is fixed at the other end of the hydraulic cylinder barrel; the other end of the piston rod extends out of the other end of the hydraulic cylinder barrel, one end of the horizontal pointer is fixed on the end head of the other end of the piston rod, and the other end of the horizontal pointer points to the scale marks.

6. The variable injection timing adjusting apparatus for diesel engine according to claim 1, wherein the helical angle β of said helical tooth head is 8-15 °.