阅读说明：本技术 共轨系统驱动的发动机缸内制动装置 (Common rail system driven in-cylinder brake device of engine ) 是由 王立峰 王秀强 牟大为 王孟晓 吴龙龙 王昊天 吴鹏超 从田增 苏明涛 于 2019-10-19 设计创作，主要内容包括：本发明公开了一种共轨系统驱动的发动机缸内制动装置,包括：用于驱动气门摇臂摆动的油缸装置,油缸装置包括缸体、第一缸盖、第二缸盖、油塞、油塞杆和回位弹簧；油塞杆从第一缸盖伸出并抵靠于气门摇臂的上部端面；开设于第二缸盖的进油孔和回油孔分别与油缸的无杆腔连通,进油孔通过进油管路与共轨油管连通,所述进油管路上设置有高频开关电磁阀,高频开关电磁阀与发动机的ECU电连接。本发明在缸内制动过程中通过ECU控制供油系统继续工作,并利用共轨油管内的燃油压力作为排气门的开启动力来实现压缩释放式的缸内制动,无需在凸轮轴的控制凸轮上设置制动凸起,结构更为简单,使用更为可靠,特别适用于高压共轨柴油发动机。(the invention discloses an engine cylinder braking device driven by a common rail system, which comprises: the oil cylinder device is used for driving the valve rocker to swing and comprises a cylinder body, a first cylinder cover, a second cylinder cover, an oil plug rod and a return spring; the oil plug rod extends out of the first cylinder cover and abuts against the upper end face of the valve rocker; and the oil inlet hole and the oil return hole which are arranged on the second cylinder cover are respectively communicated with the rodless cavity of the oil cylinder, the oil inlet hole is communicated with the common rail oil pipe through an oil inlet pipeline, and the high-frequency switching electromagnetic valve is arranged on the oil inlet pipeline and is electrically connected with an ECU (electronic control unit) of the engine. The invention controls the oil supply system to continue working through the ECU in the in-cylinder braking process, realizes the compression release type in-cylinder braking by using the fuel pressure in the common rail oil pipe as the opening power of the exhaust valve, does not need to arrange a braking bulge on the control cam of the cam shaft, has simpler structure and more reliable use, and is particularly suitable for a high-pressure common rail diesel engine.)

1. An in-cylinder brake device for an engine driven by a common rail system, comprising:

The oil cylinder device is used for driving a valve rocker of the engine to swing and comprises a cylinder body, a first cylinder cover, a second cylinder cover, an oil plug rod and a return spring;

The first cylinder cover and the second cylinder cover are respectively installed at two ends of the cylinder body, the oil plug is arranged in the cylinder body, the oil plug rod is fixed to the oil plug, and the oil plug rod extends out of the first cylinder cover and abuts against the upper end face of the valve rocker;

in the cylinder body, a cavity which is positioned between the oil plug and the first cylinder cover and is penetrated by the oil plug rod is marked as a rod cavity, a cavity which is positioned between the oil plug and the second cylinder cover is marked as a rodless cavity, and the return spring is sleeved on the oil plug rod and is arranged in the rod cavity;

The second cylinder cover is provided with an oil inlet hole and an oil return hole, the oil inlet hole and the oil return hole are respectively communicated with the rodless cavity, the oil inlet hole is communicated with a common rail oil pipe of the common rail system through an oil inlet pipeline, the oil return hole is communicated with a fuel tank of the engine through an oil return pipeline, a high-frequency switch electromagnetic valve is arranged on the oil inlet pipeline and electrically connected with an ECU (electronic control unit) of the engine, and a throttling device is arranged on the oil return pipeline.

2. the common rail system driven engine in-cylinder brake apparatus of claim 1, wherein said second cylinder head is opened with an oil collection chamber, said oil collection chamber is communicated with said rodless chamber, said oil inlet hole and said oil return hole, respectively.

3. The common rail system driven engine in-cylinder brake apparatus of claim 1, wherein said second cylinder head is integral with said cylinder block.

4. The common rail system driven engine in-cylinder brake apparatus of claim 1, wherein said oil plug rod is provided integrally with said oil plug.

5. The common rail system driven engine in-cylinder brake apparatus of claim 1, wherein said throttling means is a throttle valve.

6. the common rail system driven engine in-cylinder brake device according to claim 1, wherein said high frequency on-off solenoid valve is a two-position normally closed on-off solenoid valve that matches a fuel injection frequency of said engine.

Technical Field

The invention relates to the technical field of in-cylinder braking of engines, in particular to a compression release type in-cylinder braking device of a diesel engine, which is driven by high-pressure fuel oil in a common rail oil pipe of a common rail system.

Background

the in-cylinder braking technology of the engine mainly goes through the development processes of exhaust butterfly valve braking, air-release braking, compression release braking and the like, wherein the compression release braking technology is the best technology of the braking performance of the engine at present, and the basic principle is as follows: when the engine is dragged backwards, the piston compresses the gas in the cylinder to generate braking power in the process of ascending the compression stroke piston. Before the compression top dead center, the compression release type brake device drives the exhaust valve to open a certain opening degree, compressed high-temperature and high-pressure charging in the cylinder is discharged, at the moment, the pressure in the cylinder is rapidly reduced, after a certain crank angle, the exhaust valve is closed again, the piston moves downwards, and as the charging in the cylinder is greatly reduced, the working of the charging in the cylinder on the piston is also greatly reduced, and the counter braking power of the compression charging in the cylinder on the piston is reduced or eliminated.

compression release braking technology, generally combined with exhaust butterfly valve braking, during the exhaust stroke, the exhaust passage of the engine is closed by the butterfly valve, back pressure is established, and the piston is subjected to the pressure of gas during the upward process, so that the upward speed is reduced, the power loss of the piston is increased, and the braking power is generated again.

Chinese utility model patent CN201241740Y discloses a four-stroke internal combustion engine rocking arm integrated form arresting gear, it sets up two braking archs on the control cam for realize opening the (air) intake valve before the intake stroke finishes and increase the air input, open the cylinder braking that the exhaust valve released pressure realized the engine before the compression stroke finishes, in order to offset the valve lift that the arch arouses of braking when the engine normal operating, need set up hydraulic control's clearance compensation mechanism on the rocking arm. Because the normal operating state accounts for the vast majority of the operating state of the whole engine, the clearance compensation mechanism is in the working state in the vast majority of the operating time of the engine, higher requirements on reliability and the like are provided, and the structure is more complex.

Common rail fuel injection systems are widely used in diesel engines. A common rail fuel injection system, referred to as a common rail system or a high pressure common rail system for short, refers to a fuel injection system that completely separates the generation of injection pressure and the injection process from each other in a closed-loop system consisting of a high pressure oil pump, a pressure sensor, and an Electronic Control Unit (ECU). The high-Pressure fuel oil is delivered to a common Rail oil pipe (Rail) by a high-Pressure oil pump, and the oil Pressure in the common Rail oil pipe is accurately controlled, so that the Pressure (Pressure) of the high-Pressure oil pipe is irrelevant to the rotating speed of an engine, and the degree of the oil supply Pressure of a diesel engine changing along with the rotating speed of the engine can be greatly reduced. The high-pressure common rail system realizes the separation of the pressure establishment and the injection process, so that the control process is more flexible, the precise control of small oil quantity can be more accurately realized, and the multiple injection can be better realized.

In the braking process in the diesel engine cylinder, the oil injector stops injecting oil in the cylinder, and the oil supply system is in an idle state. How to realize in-cylinder braking of an engine by using fuel pressure in a common rail oil pipe of an engine common rail system as driving force is a new research subject.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the common rail system-driven engine in-cylinder brake device, which realizes compression release type in-cylinder braking by controlling the engine oil supply system to continue working and using the fuel pressure in the common rail oil pipe as the opening power of the exhaust valve in the in-cylinder braking process.

In order to solve the above technical problem, the present invention provides an engine in-cylinder brake device driven by a common rail system, comprising: the oil cylinder device is used for driving a valve rocker of the engine to swing and comprises a cylinder body, a first cylinder cover, a second cylinder cover, an oil plug rod and a return spring; the first cylinder cover and the second cylinder cover are respectively installed at two ends of the cylinder body, the oil plug is arranged in the cylinder body, the oil plug rod is fixed to the oil plug, and the oil plug rod extends out of the first cylinder cover and abuts against the upper end face of the valve rocker; in the cylinder body, a cavity which is positioned between the oil plug and the first cylinder cover and is penetrated by the oil plug rod is marked as a rod cavity, a cavity which is positioned between the oil plug and the second cylinder cover is marked as a rodless cavity, and the return spring is sleeved on the oil plug rod and is arranged in the rod cavity; the second cylinder cover is provided with an oil inlet hole and an oil return hole, the oil inlet hole and the oil return hole are respectively communicated with the rodless cavity, the oil inlet hole is communicated with a common rail oil pipe of the common rail system through an oil inlet pipeline, the oil return hole is communicated with a fuel tank of the engine through an oil return pipeline, a high-frequency switch electromagnetic valve is arranged on the oil inlet pipeline and electrically connected with an ECU (electronic control unit) of the engine, and a throttling device is arranged on the oil return pipeline.

The second cylinder cover is provided with an oil collecting cavity, and the oil collecting cavity is communicated with the rodless cavity, the oil inlet hole and the oil return hole respectively.

Wherein the second cylinder head is integrated with the cylinder body.

Wherein, the oil plug rod and the oil plug are integrated.

Wherein the throttling device is a throttle valve.

The high-frequency switching electromagnetic valve is a two-position two-way normally closed switching electromagnetic valve matched with the fuel injection frequency of the engine.

After the technical scheme is adopted, the compression release type in-cylinder braking is realized by controlling an engine oil supply system to continuously work through the ECU in the in-cylinder braking process and using the fuel pressure in a common rail oil pipe of a common rail system as the opening power of an exhaust valve. When the engine is in a normal working mode, the electromagnetic switch valve is closed, and the oil cylinder device does not act; when the engine enters an in-cylinder braking mode, the high-frequency electromagnetic switch valve enables the oil cylinder device to act under the control of the ECU, compared with the prior art, a braking bulge does not need to be arranged on a control cam of a cam shaft, the structure is simpler, the use is more reliable, and the high-pressure common rail diesel engine is particularly suitable for a high-pressure common rail diesel engine.

Drawings

FIG. 1 is a schematic block diagram of an embodiment of an in-cylinder brake device of an engine actuated by a common rail system according to the present invention;

In the figure, 10-exhaust valve, 11-valve spring, 12-valve rocker, 13-rocker shaft, 14-push rod, 20-common rail oil pipe, 30-high frequency switch electromagnetic valve, 40-oil cylinder device, 41-cylinder body, 42-return spring, 43-oil plug, 44-oil collecting cavity, 45-first cylinder cover, 46-oil plug rod, 47-oil inlet, 48-oil return, 50-throttle valve and 60-fuel tank.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 shows an in-cylinder brake device of an engine driven by a common rail system. As shown in fig. 1, the valve rocker 12 is rotatably mounted on a rocker shaft 13, the push rod 14 and the exhaust valve 10 are respectively arranged on two sides of the rocker shaft 13, when the push rod 14 pushes the valve rocker 12 from one side to swing around the rocker shaft 13 under the action of a camshaft (not shown), the other side of the valve rocker 12 presses the exhaust valve 10, and the valve is opened; when the camshaft rotates a specified angle, the exhaust valve 10 returns under the action of the valve spring 11, and the valve is closed.

The oil cylinder device 40 is used for driving the valve rocker 12 of the engine to swing, and the oil cylinder device 40 comprises a cylinder body 41, a first cylinder cover 45, a second cylinder cover, an oil plug 43, an oil plug rod 46 and a return spring 42.

The first cylinder cover 45 and the second cylinder cover are respectively installed at two ends of the cylinder body 41 (in this embodiment, the second cylinder cover and the cylinder body 41 are integrally arranged, and may also be of a split structure), the oil plug 43 is arranged in the cylinder body 41, the oil plug rod 46 is fixed to the oil plug 43 (in this embodiment, the oil plug rod 46 and the oil plug 43 are integrally arranged, and may also be of a split structure), and the oil plug rod 46 extends from the first cylinder cover 45 and abuts against the upper end face of the valve rocker 12.

In the cylinder body 41, a cavity which is located between the oil plug 43 and the first cylinder cover 45 and is penetrated by the oil plug rod 46 is marked as a rod cavity, a cavity which is located between the oil plug 43 and the second cylinder cover is marked as a rod-free cavity, and the return spring 42 is sleeved on the oil plug rod 46 and is arranged in the rod cavity.

The second cylinder cover is provided with an oil inlet 47 and an oil return hole 48, the oil inlet 47 and the oil return hole 48 are respectively communicated with the rodless cavity, the oil inlet 47 is communicated with a common rail oil pipe 20 of the common rail system through an oil inlet pipeline, the oil return hole 48 is communicated with a fuel tank 60 of the engine through an oil return pipeline, the oil inlet pipeline is provided with a high-frequency switch electromagnetic valve 30 (in the embodiment, the high-frequency switch electromagnetic valve 30 is a two-position two-way normally closed switch electromagnetic valve matched with the fuel injection frequency of the engine), the high-frequency switch electromagnetic valve 30 is electrically connected with an ECU (electronic control unit) of the engine, and the oil return pipeline is provided with a throttling device (in the embodiment, the throttling device is a throttling valve.

In the invention, the second cylinder cover is provided with an oil collecting cavity 44, and the oil collecting cavity 44 is respectively communicated with the rodless cavity, the oil inlet 47 and the oil return 48. The oil collection chamber 44 is provided for the purpose of facilitating the provision of the oil inlet hole 47 and the oil return hole 48, and preventing the oil plug 43 from closing the oil inlet hole 47 and the oil return hole 48 when it is located at the end of the cylinder block 41.

The working principle of the above embodiment of the present invention is briefly described as follows:

When the engine is in a normal operation mode, the high-frequency electromagnetic switch valve 30 is closed, and the high-pressure fuel in the common rail 20 is supplied to the engine cylinder through a high-pressure fuel pipe and an electromagnetic nozzle (which are in a conventional configuration and are not shown in the figure).

When the engine enters the in-cylinder braking mode, the engine ECU controls the electromagnetic nozzle to stop in-cylinder oil injection. When the engine is in a compression stroke, the air inlet/outlet valve is closed, compressed air in the cylinder generates reverse thrust on the piston to generate braking power, before the piston approaches a top dead center, the ECU controls the high-frequency switch electromagnetic valve 30 to be opened and maintain the opening state for a certain time, and high-pressure fuel in the common rail oil pipe 20 enters a rodless cavity of the oil cylinder device and partially flows back to the fuel tank 60 through the throttle valve 50. Due to the action of the throttle valve 50, the fuel entering the rodless cavity is far larger than the fuel leaked and flowing back to the fuel tank 60, the fuel in the rodless cavity generates pressure to push the oil plug 43 to move downwards, further push the valve rocker 12 and the exhaust valve 10 to open a certain opening degree, release part of compressed gas in the cylinder, reduce the pressure in the cylinder, and avoid or reduce the downward thrust of the gas pressure on the piston when the piston moves downwards. Compared with the prior art, the brake cam of the cam shaft is not required to be provided with the brake bulge, the structure is simpler, the use is more reliable, and the brake cam is particularly suitable for a high-pressure common rail diesel engine.

After a certain crank angle, the ECU closes the high-frequency switch electromagnetic valve, fuel in the oil cavity is decompressed through the throttle valve 50, and the exhaust valve 10 is closed under the combined action of the return spring 42 and the valve spring 11, so that a working cycle is completed.

The throttle area of the throttling device is adjusted, the fuel oil discharge speed is changed, the delay opening and closing time of the exhaust valve can be adjusted, and the fuel oil discharge quantity is reduced as much as possible under the condition that the opening of the exhaust valve meets the requirement.

The present invention is not limited to the embodiments described above, and all modifications that can be made based on the concept, principle, structure and method of the present invention will fall within the scope of the present invention.