CN110454251B - Variable valve and variable geometric compression ratio integrated system of diesel engine - Google Patents
Variable valve and variable geometric compression ratio integrated system of diesel engine Download PDFInfo
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- CN110454251B CN110454251B CN201910725724.5A CN201910725724A CN110454251B CN 110454251 B CN110454251 B CN 110454251B CN 201910725724 A CN201910725724 A CN 201910725724A CN 110454251 B CN110454251 B CN 110454251B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
- F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
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- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Valve Device For Special Equipments (AREA)
Abstract
The invention provides a variable valve and variable geometric compression ratio integrated system of a diesel engine, which comprises a hydraulic cylinder, a first single-rod piston, a second single-rod piston, a valve and an electromagnetic valve, wherein the first single-rod piston is connected with the second single-rod piston through a first connecting rod; the piston end of the first single-rod piston can move up and down along the inner wall of the hydraulic cylinder, and the interior of the hydraulic cylinder is divided into a rodless cavity and a rod cavity from top to bottom; a third oil duct is arranged inside a piston rod of the first single-rod piston, and when the first single-rod piston moves to the uppermost end, the third oil duct is communicated with the rod cavity; the second single-rod piston is arranged in the air valve and can move up and down along the inner wall of the air valve, and in the moving process, a first hydraulic cavity and a second hydraulic cavity can be formed between the middle part of a rod body and the head part of the piston of the second single-rod piston and the air valve respectively. The invention realizes different valve motion laws and different geometric compression ratios simultaneously by controlling the electro-hydraulic valve.
Description
Technical Field
The invention belongs to the field of internal combustion engine systems, and particularly relates to a variable valve and variable geometric compression ratio integrated system of a diesel engine.
Background
Internal combustion engines are still the most thermally efficient prime mover with the greatest power per unit volume and weight, and are widely used, however, with the gradual shortage of world energy and the continuous deterioration of environmental resources, the internal combustion engines are required to meet stricter economic and emission regulations.
The traditional internal combustion engine adopts a camshaft with a fixed molded line to drive a valve, so that the emission and the oil consumption of the internal combustion engine cannot be optimal at all working points; meanwhile, researchers hope that the geometric compression ratio is properly increased under medium and low loads to further improve oil consumption, and the geometric compression ratio is reduced under a high-load working condition to avoid detonation, so that higher power output is achieved. Therefore, most of the novel internal combustion engines adopt a variable valve technology and even a variable geometric compression ratio technology to control emission and reduce oil consumption.
Compared with other variable valve technologies, the electro-hydraulic directly driven cam-free air distribution technology is relatively simple in structure and high in response speed. The variable geometric compression ratio mode mainly comprises an eccentric bushing mode, a cylinder cover moving mode, a multi-connecting rod mode, a variable piston mode, a combustion chamber volume variable mode and the like. The variable mode of combustion chamber volume changes the combustion chamber volume through the reciprocating motion of the auxiliary piston arranged in the cylinder, compared with other modes, the variable mode has simple structure and control, but because the area of the bottom plate of the cylinder cover is occupied, the area of the intake valve and the exhaust valve is reduced, and the negative influence is generated on the charging efficiency.
For diesel engines, the highest explosion pressure can reach more than 20MPa, and the pressure of a general electro-hydraulic valve system is between 7 and 15 MPa.
Disclosure of Invention
In view of the above, the invention aims to provide a variable valve and variable geometric compression ratio integrated system of a diesel engine, which can simultaneously realize different valve motion laws and different geometric compression ratios by controlling an electro-hydraulic valve.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a variable valve and variable geometric compression ratio integrated system of a diesel engine comprises a hydraulic cylinder, a first single-rod piston, a second single-rod piston and a valve; the piston end of the first single-rod piston can move up and down along the inner wall of the hydraulic cylinder, and the interior of the hydraulic cylinder is divided into a rodless cavity and a rod cavity from top to bottom; the wall surface of the hydraulic cylinder is provided with a first oil duct and a second oil duct which are respectively communicated with the rodless cavity and the rod cavity, and the outer sides of the first oil duct and the second oil duct are connected with an external oil source through electromagnetic valves; a third oil duct is arranged in the piston rod of the first single-rod piston, one end of the third oil duct is communicated with the bottom end face of the piston rod, the other end of the third oil duct is communicated with the side face of the piston rod, and when the first single-rod piston moves to the uppermost end, the third oil duct is communicated with the rod cavity; the piston rod end of the first single-rod piston is fixedly connected with the top of the air valve; the second single-rod piston is arranged in the air valve and can move up and down along the inner wall of the air valve, and in the moving process, a first hydraulic cavity and a second hydraulic cavity can be formed between the middle part of a rod body and the head part of the piston of the second single-rod piston and the air valve respectively; a fourth oil duct is axially arranged in the second single-rod piston, and two ends of the fourth oil duct are respectively communicated with the third oil duct and the second hydraulic cavity; and a fifth oil duct communicated with the first hydraulic cavity and the fourth oil duct is radially arranged in the second single-rod piston.
Furthermore, the piston rod of the second single-rod piston comprises a first section and a second section which have different diameters, the diameter of the first section far away from the piston end is larger than that of the second section, an inner cavity and a stepped structure which are matched with the first section and the second section are arranged in the valve, and a first hydraulic cavity is formed at the stepped structure in the movement process of the second single-rod piston.
Furthermore, an annular groove for communicating the fourth oil duct with the second hydraulic cavity is formed in the joint of the piston rod of the second single-rod piston and the piston end.
Furthermore, the electromagnetic valve is a three-position four-way electromagnetic valve, a high-pressure oil source and a low-pressure oil source are externally connected with the electromagnetic valve, and the pressure of the high-pressure oil source is smaller than the highest combustion pressure in the diesel engine cylinder.
Compared with the prior art, the invention has the following advantages:
the invention realizes different valve motion laws and different geometric compression ratios by controlling the electro-hydraulic valve, has relatively simple structure and control, high integration degree, does not occupy the area of the cylinder cover bottom plate, and does not generate adverse effect on the inflation efficiency.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic illustration of an embodiment of the present invention in a valve open state;
FIG. 2 is a schematic diagram of the embodiment of the present invention in a valve closed state (variable geometric compression ratio);
FIG. 3 is a schematic diagram of an electromagnetic valve and an external high-low pressure oil source according to an embodiment of the present invention.
Description of reference numerals:
1. the hydraulic cylinder comprises a hydraulic cylinder, 2, a first single-rod piston, 3, a third oil duct, 4, a second single-rod piston, 5, a first hydraulic cavity, 6, a fourth oil duct, 7, a second hydraulic cavity, 8, an air valve, 9, a fifth oil duct, 10, a second oil duct, 11, a first oil duct and 12 an electromagnetic valve.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
As shown in fig. 1 to 3, the system of the present embodiment includes a hydraulic cylinder 1, a first single-rod piston 2, a second single-rod piston 4, and a valve 8;
the piston end of the first single-rod piston 2 can move up and down along the inner wall of the hydraulic cylinder 1, and the interior of the hydraulic cylinder 1 is divided into a rodless cavity and a rod cavity from top to bottom; the wall surface of the hydraulic cylinder 1 is provided with a first oil duct 11 and a second oil duct 10, two ends of the outer sides of the first oil duct 11 and the second oil duct 10 are connected with an electromagnetic valve 12, the electromagnetic valve 12 is a three-position four-way electromagnetic valve and is connected with an external oil source through the three-position four-way electromagnetic valve, and two ends of the inner side of the electromagnetic valve are respectively communicated with the rodless cavity and the rod cavity;
a third oil duct 3 is arranged in the piston rod of the first single-rod piston 2, one end of the third oil duct is communicated with the end surface of the bottom of the piston rod, the other end of the third oil duct is communicated with the side surface of the piston rod, and when the first single-rod piston 2 moves to the uppermost end, the third oil duct 3 is communicated with the rod cavity;
the piston rod end of the first single-rod piston 2 is fixedly connected with the top of the valve 8;
the second single-rod piston 4 is arranged in the valve 8 and can move up and down along the inner wall of the valve 8, and in the moving process, a first hydraulic cavity 5 and a second hydraulic cavity 7 can be formed between the middle part of a rod body and the head part of the second single-rod piston 4 and the valve 8 respectively; a fourth oil duct 6 is axially arranged in the second single-rod piston 4, and two ends of the fourth oil duct 6 are respectively communicated with the third oil duct 3 and the second hydraulic cavity 7; and a fifth oil channel 9 communicated with the first hydraulic cavity 5 and the fourth oil channel 6 is radially arranged in the second single-rod piston 4.
The piston rod of the second single-rod piston 4 comprises a first section and a second section which have different diameters, the diameter of the first section far away from the piston end is larger than that of the second section, an inner cavity and a stepped structure which are matched with the first section and the second section are arranged in the valve 8, and a first hydraulic cavity 5 is formed at the stepped structure in the movement process of the second single-rod piston 4; the height of the first hydraulic chamber 5 limits the maximum distance the second single rod piston 4 can move up and down along the inner wall of the valve 8.
And an annular groove is formed at the joint of the piston rod and the piston end of the second single-rod piston 4, so that the fourth oil duct 6 is communicated with the second hydraulic cavity 7.
The three-position four-way electromagnetic valve is externally connected with a high-pressure oil source and a low-pressure oil source, and the pressure of the high-pressure oil source is less than the highest combustion pressure in the diesel engine cylinder.
The working process of the embodiment is as follows:
when the electromagnetic valve 12 is in the upper function, as shown in fig. 1, at this time, the first oil passage 11 is communicated with a high-pressure oil source, the second oil passage 10 is communicated with a low-pressure oil source, and under the action of hydraulic pressure, the first single-rod piston 2 moves downward to open the valve.
When the electromagnetic valve 12 is in the lower position, the first oil passage 11 is communicated with a low-pressure oil source, the second oil passage 10 is communicated with a high-pressure oil source, the first single-rod piston 2 moves upwards under the action of hydraulic pressure, and the valve begins to fall back until the valve is closed, as shown in fig. 2. At this time, the first single-rod piston 2 moves to the uppermost end, the third oil duct 3 is communicated with the rod chamber and further communicated with a high-pressure oil source, because the pressure in the engine cylinder is low just after the valve is closed, the second single-rod piston 4 moves downwards relative to the valve 8 under the action of hydraulic pressure, the volume of the first hydraulic chamber 5 is gradually reduced until the volume is 0, and at this time, the volume is used as a reference position before the geometric compression ratio is changed, and because the second single-rod piston 4 protrudes outwards to the maximum, the space in the combustion chamber is the minimum and corresponds to the maximum geometric compression ratio. When the pressure in the engine cylinder is increased, particularly when the pressure sharply increased during combustion exceeds the pressure of a high-pressure oil source, under the comprehensive acting force, the second single-rod piston 4 moves upwards relative to the valve 8, the volume of the first hydraulic cavity 5 is gradually increased, the geometric compression ratio is gradually reduced, and when a preset geometric compression ratio position is reached, the electromagnetic valve 12 is controlled to be in a neutral position function, the first oil channel 11 and the second oil channel 10 are in a disconnected state, and the geometric compression ratio is solidified.
This causes the valve to open and close by repeating the cycle.
Because the geometric compression ratio has a reference position, the accurate control of the geometric compression ratio can be realized by calibrating and adopting open-loop control, and the control is simple.
In summary, by controlling the timing of switching between the upper function and the lower function of the solenoid valve 12, the valve motion law can be changed, and by further controlling the switching between the middle function, the geometric compression ratio can be changed.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (4)
1. A variable valve and variable geometric compression ratio integrated system of a diesel engine is characterized in that: comprises a hydraulic cylinder (1), a first single-rod piston (2), a second single-rod piston (4) and a valve (8);
the piston end of the first single-rod piston (2) can move up and down along the inner wall of the hydraulic cylinder (1), and the interior of the hydraulic cylinder (1) is divided into a rodless cavity and a rod cavity from top to bottom; the wall surface of the hydraulic cylinder (1) is provided with a first oil duct (11) and a second oil duct (10) which are respectively communicated with the rodless cavity and the rod cavity, and the outer sides of the first oil duct (11) and the second oil duct (10) are connected with an external oil source through an electromagnetic valve (12);
a third oil duct (3) is arranged in a piston rod of the first single-rod piston (2), one end of the third oil duct is communicated with the end surface of the bottom of the piston rod, the other end of the third oil duct is communicated with the side surface of the piston rod, and when the first single-rod piston (2) moves to the uppermost end, the third oil duct (3) is communicated with the rod cavity;
the piston rod end of the first single-rod piston (2) is fixedly connected with the top of the air valve (8);
the second single-rod piston (4) is arranged in the air valve (8) and can move up and down along the inner wall of the air valve (8), and in the moving process, a first hydraulic cavity (5) and a second hydraulic cavity (7) can be formed between the middle part of a rod body and the head part of the piston of the second single-rod piston (4) and the air valve (8) respectively; a fourth oil duct (6) is axially arranged in the second single-rod piston (4), and two ends of the fourth oil duct (6) are respectively communicated with the third oil duct (3) and the second hydraulic cavity (7); and a fifth oil channel (9) communicated with the first hydraulic cavity (5) and the fourth oil channel (6) is radially arranged in the second single-rod piston (4).
2. The system of claim 1, wherein: the piston rod of the second single-rod piston (4) comprises a first section and a second section which are different in diameter, the diameter of the first section far away from the piston end is larger than that of the second section, an inner cavity and a stepped structure which are matched with the first section and the second section are arranged in the valve (8), and a first hydraulic cavity (5) is formed in the stepped structure in the movement process of the second single-rod piston (4).
3. The system of claim 1, wherein: and an annular groove for communicating the fourth oil duct (6) with the second hydraulic cavity (7) is formed in the joint of the piston rod of the second single-rod piston (4) and the piston end.
4. The system of claim 1, wherein: the electromagnetic valve (12) is a three-position four-way electromagnetic valve, a high-pressure oil source and a low-pressure oil source are externally connected with the electromagnetic valve, and the pressure of the high-pressure oil source is less than the highest combustion pressure in a diesel engine cylinder.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910725724.5A CN110454251B (en) | 2019-08-07 | 2019-08-07 | Variable valve and variable geometric compression ratio integrated system of diesel engine |
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| CN201910725724.5A CN110454251B (en) | 2019-08-07 | 2019-08-07 | Variable valve and variable geometric compression ratio integrated system of diesel engine |
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| CN110454251A CN110454251A (en) | 2019-11-15 |
| CN110454251B true CN110454251B (en) | 2020-11-06 |
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| CN107060935A (en) * | 2017-03-24 | 2017-08-18 | 中国北方发动机研究所(天津) | A kind of hydraulic pressure variable valve device |
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| DE19727584C1 (en) * | 1997-06-28 | 1998-10-08 | Daimler Benz Ag | Compression brake for internal combustion engine |
| JP5338976B2 (en) * | 2010-04-21 | 2013-11-13 | トヨタ自動車株式会社 | Internal combustion engine |
| JP5821772B2 (en) * | 2012-05-10 | 2015-11-24 | トヨタ自動車株式会社 | Combustion chamber volume adjustment method and engine manufacturing method |
| CN103670663A (en) * | 2012-09-11 | 2014-03-26 | 窦斌 | Sleeved air valve structure for changing internal combustion engine combustion chamber volume |
| KR101534709B1 (en) * | 2013-12-18 | 2015-07-08 | 현대자동차 주식회사 | Variable compression ratio engine |
| WO2017123478A1 (en) * | 2016-01-14 | 2017-07-20 | Nautilus Engineering, Llc | Improved systems and methods of compression ignition engines |
| CN106121763A (en) * | 2016-08-05 | 2016-11-16 | 天津大学 | Electro-hydraulic variable valve system with one-way throttle valve buffering |
| CN107676144B (en) * | 2017-09-30 | 2019-12-27 | 中国北方发动机研究所(天津) | Hydraulic variable valve mechanism for 2/4 stroke engine |
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- 2019-08-07 CN CN201910725724.5A patent/CN110454251B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103216290A (en) * | 2013-04-09 | 2013-07-24 | 江苏公大动力技术有限公司 | Variable lift driver |
| CN107060935A (en) * | 2017-03-24 | 2017-08-18 | 中国北方发动机研究所(天津) | A kind of hydraulic pressure variable valve device |
| CN108506063A (en) * | 2018-03-05 | 2018-09-07 | 中国北方发动机研究所(天津) | A kind of two or four stroke hydraulic variable valve mechanism of no valve spring engine |
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