阅读说明：本技术 无级偏心轮式可变压缩比活塞 (Stepless eccentric wheel type variable compression ratio piston ) 是由 苏岩 宋泽阳 李小平 王忠恕 解方喜 韩永强 王永珍 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种通过在活塞上安装特殊偏心活塞销套从而实现可变压缩比的活塞,以此克服现有可变压缩比技术存在的机械结构复杂、零件繁多与只能实现两级式调节的问题。无级偏心轮式可变压缩比活塞包括：电机、齿轮、卡环、带槽式活塞销、带齿轮偏心式活塞销套筒、从动偏心式活塞销套筒、螺栓、活塞体；电机在活塞销内部,螺栓与电机为滑动连接,螺栓与活塞体螺纹连接,电机与活塞销之间为间隙配合,电机轴通过键与齿轮装配为固定连接,齿轮与带齿轮偏心式活塞销套筒啮合,活塞销与带齿轮偏心式活塞销套筒、从动偏心式活塞销套筒为滑动连接,卡环安装在齿轮外侧环形凹槽中。(The invention discloses a piston which realizes a variable compression ratio by installing a special eccentric piston pin bush on the piston, thereby solving the problems of complicated mechanical structure, various parts and capability of only realizing two-stage adjustment in the prior variable compression ratio technology. The stepless eccentric wheel type variable compression ratio piston comprises: the device comprises a motor, a gear, a clamping ring, a grooved piston pin, a toothed wheel eccentric piston pin sleeve, a driven eccentric piston pin sleeve, a bolt and a piston body; the motor is inside the piston pin, and the bolt is sliding connection with the motor, and bolt and piston body threaded connection are clearance fit between motor and the piston pin, and the motor shaft passes through the key and gear assembly be fixed connection, gear and the eccentric formula piston pin sleeve meshing of taking the gear, and the piston pin is sliding connection with the eccentric formula piston pin sleeve of taking the gear, driven eccentric formula piston pin sleeve, and the snap ring is installed in gear outside annular groove.)

1. a stepless eccentric wheel type variable compression ratio piston is characterized by comprising: the device comprises a motor (1), a gear (2), a clamping ring (3), a grooved piston pin (4), a toothed wheel eccentric piston pin sleeve (5), a driven eccentric piston pin sleeve (6), a bolt (7) and a piston body (8).

Bolt (7) and piston body (8) lower part are threaded connection, bolt (7) pass slotted hole and motor (1) sliding connection of trough of belt piston pin (4), and be threaded connection with piston body (8) upper portion, motor (1) is clearance fit in trough of belt piston pin (4), motor (1) axle and gear (2) use the key assembly to be fixed connection, gear (2) and toothed wheel eccentric piston pin sleeve (5) are gear connection, toothed wheel eccentric piston pin sleeve (5) and driven eccentric piston pin sleeve (6) and trough of belt piston pin (4) assembly are sliding connection, toothed wheel eccentric piston pin sleeve (5) and driven eccentric piston pin sleeve (6) and piston body (8) assembly are sliding connection, snap ring (3) assembly is in the piston pin ring channel in gear (2) outside.

2. The stepless eccentric wheel type variable compression ratio piston according to claim 1 is characterized in that the motor (1) has a clearance fit inside the grooved piston pin (4), the motor (1) is in sliding connection with the bolt (7), the bolt (7) and the upper part and the lower part of the piston body (8) are in threaded connection, and the relative position of the motor (1) and the piston body (8) changes along with the change of the compression ratio.

3. The stepless eccentric wheel type variable compression ratio piston according to claim 1 is characterized in that a shaft of the motor (1) is assembled with the gear (2) by a key, an output shaft of the motor (12) is collinear with a shaft of the gear (2), the clamping ring (3) is arranged in an annular groove on the outer side of the gear (2), the eccentric piston pin sleeve (5) with the gear is in gear connection with the gear (2), and the shaft of the gear (2) is not collinear with the shaft of the gear with the eccentric piston pin sleeve (5).

4. a variable compression ratio piston with stepless eccentric wheels according to claim 1, characterized in that the profile of the eccentric piston pin sleeve (5) with gears is the same as the profile of the driven eccentric piston pin sleeve (6) and is an eccentric circle. The eccentric piston pin sleeve (5) with the gear, the driven eccentric piston pin sleeve (6), the grooved piston pin (4) and the piston body (8) are in sliding connection. The contact surface of the piston body (8) and the sleeves (5) and (6) is circular in outline.

5. A stepless eccentric wheel type variable compression ratio piston according to claim 1, characterized in that the grooved piston pin (4) has symmetrical notches at the upper and lower sides, the bolt (7) penetrates the piston pin through the groove of the grooved piston pin (4), and the grooved piston pin (4) is not in contact with the bolt (7).

Technical Field

The invention relates to an automobile engine piston, in particular to a stepless eccentric wheel type variable compression ratio piston.

Background

The compression ratio of the engine is the ratio of the volume of the cylinder when the piston moves to the bottom dead center to the volume of the cylinder when the piston moves to the top dead center, and the performance and efficiency of the engine can be effectively improved by increasing the compression ratio. Firstly, when the compression ratio is increased, the density of the mixed gas in the cylinder chamber can be increased when the piston moves to the top dead center, and the distance between molecules is reduced, so that fuel molecules and oxygen molecules are easier to interact, and the mixed gas is easier to ignite. The second smaller combustion space allows for faster completion of the combustion process, and therefore engine performance is improved. However, an increase in the compression ratio causes problems, an increase in the compression ratio increases the tendency to knock, and a high compression ratio places high demands on the gasoline quality. To solve this problem, research is now being focused at home and abroad into the development of variable compression ratio engines. The variable compression ratio is that the compression ratio of the engine is changed in real time through a control means so that the engine adopts a high compression ratio under the working condition of medium and low load to improve the heat efficiency and the fuel economy of the engine; and the lower compression ratio is adopted to prevent the generation of knocking under the high-load working condition.

Introduction of typical cases: the Sabo SVC (variable compression ratio) engine developed at the Japanese interior tile vehicle show is an in-line 5-cylinder four-valve engine with the displacement of 1598cc, but the working efficiency is very remarkable, and the compression ratio of the engine can be in the range of 8:1 to 14: 1, the maximum power is 225 p, and the maximum torque is 304 nm. The engine performance is similar to that of the Honda 3.2L V6 engine, but the oil consumption is very low, namely the fuel consumption can be reduced by more than 30% compared with the common non-variable compression ratio engine under the same power. The SCV engine has the power per liter of 150 p/L, which is the highest value in the traditional car. Meanwhile, the exhaust emission standard can reach the Euro-IV standard.

with variable compression ratio technology it is possible to:

The requirement on the fuel quality is reduced, and the method is suitable for driving by multi-component fuel;

Reducing the emission of pollutants in the exhaust gas of the engine;

The working stability of the engine under different working conditions is improved;

the heat efficiency of the engine is improved, and the fuel economy of the engine is improved;

On the premise of ensuring power, the engine displacement can be further reduced, the structure is more compact, and the specific mass per liter of power is increased.

at present, the realization of the variable compression ratio of the domestic and foreign engines has a plurality of technical schemes and related patents, but most of the engines have complicated mechanical mechanisms, are not accurate enough to control the numerical value of the variable compression ratio, are difficult to solve the problem of balance in the work of the engines, increase the quality and the volume of the engines, and can only realize the problems of two-pole type compression ratio adjustment and the like. For example, a Sabo SVC engine has a separate cooling system for the engine because the integrated cylinder head can deflect. The cooling oil duct of the system is connected with the cylinder body and sealed by a rubber key, but the rubber workpiece cracks due to stress fatigue after long-term reciprocating work, and then the oil duct of the engine leaks oil. Moreover, the Sabo SCV engine is added with a hydraulic pushing device, so that the structure of the engine is more complicated. Furthermore, in terms of software, Sabo did not have a sophisticated and reliable set of control logic at that time to ensure stable engine operation at continuously variable compression ratios. Therefore, this engine is not put into practical use until it is bankruptcy. The daily production realizes the mass production of the variable compression ratio engine at the end of 2018, and the adopted technology is a multi-connecting-rod technology. The engine is additionally provided with a VCR connecting rod mechanism and a control shaft on the original crank connecting rod mechanism. The VCR linkage is formed by a rotating crank pin lever and a connecting rod of one end thereof with the control shaft. When the control shaft rotates, the control shaft connecting rod drives the crank pin to rotate, and the lever swings. Thereby promoting the top dead center position of the piston to move up and down and realizing the variable compression ratio. However, the car carrying the variable compression ratio engine has only a few actual cars in the second quarter of 2019, and the reason for this is that the multi-link variable compression ratio technology is high in material and processing precision, so that a large assembly plant with a laggard technology cannot assemble the car, the native capacity in japan is low, and the capacity of the car is seriously insufficient due to problems such as value transportation duty and the like. Therefore, the VC-TURBO engine produced in daily life still has a plurality of difficulties in the mass production process because the variable compression ratio mechanism is too precise and complicated.

Disclosure of Invention

The invention aims to solve the technical problems of complex structure, multiple parts, overlarge increase of the volume and the mass of an engine and poor sealing performance in the prior art and provides a variable compression ratio piston.

in order to solve the technical problems, the invention adopts the following technical scheme: the stepless eccentric wheel type piston with the variable compression ratio comprises a motor, a gear, a clamping ring, a grooved piston pin, an eccentric piston pin sleeve with the gear, a driven eccentric piston pin sleeve, a bolt and a piston body.

A stepless eccentric wheel type variable compression ratio piston is characterized by comprising: the device comprises a piston pin with a groove, a motor, a gear, a clamping ring, an eccentric piston pin sleeve with the gear, a driven eccentric piston pin sleeve, a bolt and a piston body;

The bolt is in threaded connection with the lower portion of the piston body, the bolt penetrates through a slotted hole of the piston pin with the slot and is in sliding connection with the motor, the bolt is in threaded connection with the upper portion of the piston body, a gap is formed in the piston pin with the slot and is in clearance fit with the motor, the motor shaft and the gear are fixedly connected through key assembly, the gear is in gear connection with the eccentric piston pin sleeve with the gear, the eccentric piston pin with the gear is in sliding connection with the piston pin with the slot, the eccentric piston pin with the gear and the eccentric piston pin with the driven are in sliding connection with the piston pin with the slot, and the clamping ring is assembled.

In the technical scheme, the motor is in clearance connection with the inner side of the piston pin with the groove, the motor is in sliding connection with the bolt, the bolt is in threaded connection with the piston body, and the position of the motor relative to the piston body changes along with the change of the compression ratio.

In the technical scheme, a motor shaft is assembled with a gear through a key, an output shaft of the motor is collinear with a gear shaft, a snap ring is arranged in an annular groove on the outer side of the gear, an eccentric piston pin sleeve with the gear is in gear connection with the gear, and the gear shaft is not collinear with a shaft of the eccentric piston pin sleeve gear with the gear.

In the technical scheme, the outline of the outer side of the eccentric piston pin sleeve with the gear is the same as that of the outer side of the driven eccentric piston pin sleeve, and the outline of the outer side of the driven eccentric piston pin sleeve with the gear is an eccentric circle. The eccentric piston pin sleeve with the gear and the driven eccentric piston pin sleeve are in sliding connection with the piston pin and the piston body. The profile of the contact surface of the piston body and the sleeve is circular.

In the technical scheme, symmetrical notches are formed in the upper side and the lower side of a piston pin with a groove, a bolt penetrates through the piston pin through the pin groove of the piston with the groove, and the piston pin is not in contact with the bolt.

Compared with the prior structure, the invention has the beneficial effects that

1. The stepless eccentric wheel type variable compression ratio piston changes the compression ratio by additionally arranging the motor mechanism on the inner side of the piston pin, and has the advantages of simple structure, convenience in installation and good manufacturability.

2. The stepless eccentric wheel type variable compression ratio piston provided by the invention adopts eccentric gear engagement, so that the compression ratio can be stepless variable within a limit range, the compression ratio can be accurately controlled, and the requirements of an engine under different working conditions are met.

3. The stepless eccentric wheel type variable compression ratio piston realizes the variable compression ratio through the eccentric piston pin sleeve, the structure of the piston body is not greatly changed, and the structures of a piston gas ring oil ring and the like can not be influenced, so that the stability and the sealing performance are good.

4. The structure of the stepless eccentric wheel type variable compression ratio piston for realizing the variable compression ratio is concentrated in the piston, and the volume and the mass of the piston are not greatly changed after being modified, so that the mass and the volume of an engine are not obviously increased while the efficiency is increased.

5. The stepless eccentric wheel type variable compression ratio piston only partially changes the interior of the piston, and other structures such as a combustion chamber and a crankshaft connecting rod do not have special structures, so that the production of other matched parts is greatly reduced, the process cost is reduced, and the economy is high.

Drawings

The invention will be further described with reference to the accompanying drawings

fig. 1 is a full sectional view in front view of a configuration of a variable compression ratio piston of a continuously variable eccentric wheel type according to the present invention;

FIG. 2 is a left side view of the structure of the stepless eccentric wheel type variable compression ratio piston according to the present invention;

FIG. 3 is a front view of the stepless eccentric wheel type variable compression ratio piston motor according to the present invention;

FIG. 4 is a left side view of a grooved piston pin of a stepless eccentric type variable compression ratio piston according to the present invention;

FIG. 5 is a top view of a grooved piston pin of a stepless eccentric type variable compression ratio piston according to the present invention;

FIG. 6 is a front view of a stepless eccentric wheel type variable compression ratio piston with gear eccentric piston pin sleeve in full section according to the present invention;

FIG. 7 is a left side view of the eccentric piston pin sleeve of the stepless eccentric wheel type variable compression ratio piston with gear of the invention;

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

Referring to fig. 1, the stepless eccentric wheel type variable compression ratio piston of the present invention comprises a motor (1), a gear (2), a snap ring (3), a grooved piston pin (4), a toothed wheel eccentric piston pin sleeve (5), a driven eccentric piston pin sleeve (6), a bolt (7), and a piston body (8).

Referring to fig. 1 and 2, the contact profile of the piston body with the eccentric piston pin sleeve with the gear and the driven eccentric piston pin sleeve is circular. The profiles of the contact surfaces of the eccentric piston pin sleeve with the gear, the driven eccentric piston pin sleeve and the piston body are the same and are eccentric circles. The piston body is connected with the piston pin sleeve in a sliding mode. The piston body is arranged on the side of the driven eccentric piston pin sleeve, and the top and the skirt part of the piston body are provided with threaded holes which are in threaded connection with the bolts.

Referring to fig. 1 and 3, the motor is a permanent magnet type progressive motor or a hybrid type progressive motor. The motor speed regulation is controlled by a control system consisting of a double-ring pulse signal, a power driving circuit, a single chip microcomputer and the like, and a self-contained speed reducing mechanism is arranged in the motor speed regulation device and used for reducing the speed and improving the torque, and the forward and reverse rotation can be controlled. The motor is of a cylinder structure, a radial hole is formed in the non-output shaft side of the motor, and the motor penetrates through the motor without threads. The motor non-threaded hole is matched with the bolt and is in sliding connection.

Referring to fig. 1, 4 and 5, the sliding connection side of the grooved piston pin and the driven eccentric piston pin sleeve is provided with symmetrical grooves on the upper side and the lower side, the width of the groove is matched with the diameter of a bolt, and the bolt enters and penetrates through the grooved piston pin from the groove on the lower side.

Referring to fig. 1, the snap ring is a rigid structure formed by arcs with non-coincident inner and outer circle centers, and has certain elasticity, so as to prevent the gear from shifting to the outer side of the piston body, and play a role in retention and stabilization.

Referring to fig. 1 and 2, the motor is arranged inside the piston pin with the slot, and the motor guides the movement direction of the motor through the bolt fixed on the piston body, so that the motor is ensured to move up and down only along the axial direction of the bolt.

Referring to fig. 1 and 2, the output shaft of the motor is fixedly connected with the gear through a common flat key, and the gear is prevented from axially moving through the simultaneous action of the snap ring and the inside snap groove of the gear with the gear eccentric piston pin sleeve.

Working principle of stepless eccentric wheel type piston with variable compression ratio

Referring to fig. 1, when the engine needs to reduce the compression ratio under a certain working condition, the motor is started, and the output shaft of the motor rotates to drive the gear connected through the spline to rotate. The gear is engaged with the eccentric piston pin sleeve with the gear and drives the eccentric piston pin sleeve with the gear, and the driven eccentric piston pin sleeve rotates along with the eccentric piston pin sleeve. The two piston pin sleeves are arranged at the position with the shortest contour radius upwards relative to the piston body, so that the compression ratio is reduced.

Referring to fig. 1, when the engine needs to increase the compression ratio under a certain working condition, the motor is started, and the output shaft of the motor rotates to drive the gear connected through the spline to rotate. The gear is engaged with the eccentric piston pin sleeve with the gear and drives the eccentric piston pin sleeve with the gear, and the driven eccentric piston pin sleeve rotates along with the eccentric piston pin sleeve. The longest profile radius of the two piston pin sleeves is made to be upward relative to the piston body, thereby increasing the compression ratio.