CN107605563B - Auxiliary braking mechanism - Google Patents

Abstract

An auxiliary braking mechanism belongs to the field of engine valve driving, cylinder deactivation and auxiliary braking. The device comprises an air inlet/exhaust valve assembly, an air inlet/exhaust brake cam, an air inlet/exhaust driving cam, an air inlet/exhaust brake rocker arm and an air inlet/exhaust driving rocker arm; it also includes air inlet/outlet driving component, air inlet/outlet braking component and air inlet/outlet slide valve, etc. which are set on the fixing component. By controlling the states of the driving assembly and the braking assembly, the modes of four-stroke driving, two-stroke braking, cylinder deactivation and the like are realized, and the purposes of low oil consumption, low emission and high-efficiency braking of the engine are achieved. The invention has the advantages of small quantity of moving parts, compact structure, high reliability, low energy consumption, zero leakage and wide application range.

Description

an auxiliary braking mechanism

technical field

The invention relates to an auxiliary braking mechanism, belonging to the fields of engine valve driving, cylinder deactivation and auxiliary braking.

Background technique

With the sharp increase in the number of engines, vehicle safety has been paid more and more attention by people, and more and more countries have listed the auxiliary braking system as one of the necessary accessories for vehicles. However, most of the main braking system and the auxiliary braking system acting on the transmission system have problems such as easy overheating of braking components after long-term operation, rapid reduction of braking efficiency, and braking system occupying vehicle space. The engine-assisted braking technology does not have such problems, but the braking power of the existing technology is low, which cannot meet the requirements of the vehicle under heavy load on long and steep slopes. In particular, the down-size and down-speed of the engine have become the recognized development trend of energy saving and emission reduction; and when the engine is braking, the smaller the cylinder diameter and the lower the speed, the worse the braking effect. Therefore, the two-stroke braking mode is imperative. In the four-stroke driving mode and the two-stroke braking mode of the engine, the opening frequency, opening timing and opening duration of the intake/exhaust valves are greatly different, and the existing variable valve driving system cannot meet the above requirements.

Jacobo has proposed an HPD mechanism, which realizes the flexible switching between the four-stroke driving mode and the two-stroke braking mode of the engine. According to the company (SAE 2016-01-8061), the HPD mechanism has problems such as leakage. In addition, this mechanism also has problems such as a large number of moving parts and a large mass caused by the fact that the drive and brake adjustment mechanisms are installed on the rocker arm, which is not conducive to the realization of low energy consumption of the valve drive system; in addition, the movement inertia force of the rocker arm is large, The contact parts of the various parts of the system are prone to damage. The driving oil of the mechanism is led from the inside of the shaft, which is the fixed fulcrum of the rocker arm, to the moving fulcrum of the rocker arm to adjust the driving and braking adjustment mechanisms. The oil circuit is complicated and the processing is not easy. A set of auxiliary braking mechanism with compact structure, high reliability, low energy consumption, zero leakage, easy engine modification and switching between four-stroke driving mode, two-stroke braking mode and cylinder deactivation mode is imperative.

SUMMARY OF THE INVENTION

The purpose of the present invention is: by designing an auxiliary braking mechanism, to achieve: (a) in order to achieve the operation of the engine with low fuel consumption, low emission and high-efficiency braking, the mechanism is required to realize a four-stroke driving mode and a two-stroke braking mode mode, cylinder stop and other modes. (b) In order to meet the market demand, the mechanism is required to achieve compact structure, reliable operation, low energy consumption, zero leakage, easy engine modification, etc. (c) In order to expand the scope of application, it is necessary to provide different arrangements for different models. (d) In order to improve the versatility and replaceability of components, it is necessary to use standard components or design independent modules for each component.

The technical scheme adopted in the present invention is: an auxiliary braking mechanism, which includes a first exhaust valve assembly, a second exhaust valve assembly, a first intake valve assembly and a second intake valve assembly, and also includes a cam , rocker arm, brake rocker arm spring, and drive assembly, brake assembly and spool valve mounted on the fixture. The cam includes exhaust brake cam, exhaust drive cam, intake brake cam and intake drive cam, rocker arm includes exhaust brake rocker arm, exhaust drive rocker arm, intake brake rocker arm and intake drive rocker arm , the drive assembly includes an exhaust drive assembly and an intake drive assembly, the brake assembly includes an exhaust brake assembly and an intake brake assembly, and the slide valve includes an exhaust slide valve and an intake slide valve. The fixing part is also provided with a brake control chamber, a brake oil drain chamber and a drive control chamber, and the brake oil drain chamber is always in a low pressure state. The exhaust brake rocker arm spring provides spring force to drive the exhaust brake rocker arm to contact the exhaust brake cam at all times, and the intake brake rocker arm spring provides spring force to drive the intake brake rocker arm to contact the intake brake cam at all times. When the drive control chamber is in a high pressure state, the exhaust drive assembly and the intake drive assembly are in a failed state; when the drive control chamber is in a low pressure state, the exhaust drive assembly and the intake drive assembly are in a working state. The exhaust spool valve controls the connection state between the oil chamber of the exhaust brake assembly, the brake control chamber and the brake drain chamber, and the intake spool valve controls the oil chamber of the intake brake assembly, the brake control chamber and the brake drain chamber. The connection state of the oil chamber. When the brake control chamber is in a high pressure state, the exhaust brake assembly and the intake brake assembly are in a working state; when the brake control chamber is in a low pressure state, the exhaust brake assembly and the intake brake assembly are in a failure state. The exhaust brake cam drives the first exhaust valve assembly through the exhaust brake rocker arm, the exhaust brake assembly and the exhaust transmission block. After the exhaust drive cam drives the rocker arm and the exhaust drive assembly through the exhaust, it directly drives the second exhaust valve assembly, and drives the first exhaust valve assembly through the exhaust transmission block. The intake brake cam drives the first intake valve assembly through the intake brake rocker arm, the intake brake assembly and the intake transmission block. After the intake drive cam drives the rocker arm and the intake drive assembly through the intake air, it directly drives the second intake valve assembly, and drives the first intake valve assembly through the intake transmission block. In drive mode, both the drive control chamber and the brake control chamber are in a low pressure state. In braking mode, both the drive control chamber and the brake control chamber are under high pressure. In the cylinder deactivation mode, the drive control chamber is in a high pressure state, and the brake control chamber is in a low pressure state.

The drive assembly includes a drive piston, a valve bridge, a drive spring, a locking block and a locking spring. The driving piston and the valve bridge are nested together, a driving spring is arranged between them, a locking hole is arranged on one of them, and a locking ring groove and a locking oil hole are arranged on the other. Two locking blocks and a locking spring are arranged in the locking hole, and the locking spring is arranged between the two locking blocks. The lock ring groove communicates with the drive control chamber through the lock oil hole. The drive rocker arm is in contact with the drive piston, the valve bridge directly drives the second valve assembly, and the valve bridge drives the first valve assembly through the transmission block.

The brake assembly includes a brake spring, a lower brake piston and an upper brake piston. The brake rocker arm is in contact with the upper brake piston, and the lower brake piston drives the first valve assembly through the transmission block.

The spool valve includes a spool valve body, a one-way valve and a spool valve spring.

The transmission block includes a first transmission block or a second transmission block. The first transmission block is slidably connected with the valve bridge, the valve bridge drives the first valve assembly through the ring platform of the first transmission block, and the lower brake piston drives the first valve assembly through the top end of the first transmission block. The second transmission block is hinged with the valve bridge, the valve bridge drives the first valve assembly through the input end of the second transmission block, and the lower brake piston drives the first valve assembly through the output end of the second transmission block.

A cup and a push rod are arranged between the cam and the rocker arm.

The beneficial effects of the present invention are: the auxiliary braking mechanism can realize: (a) four-stroke driving mode, two-stroke braking mode, cylinder deactivation and other modes, so as to achieve the operation of the engine with low fuel consumption, low emission and high-efficiency braking . (b) The drive components, brake components, slide valves, etc. are all integrated into the fixed parts, with compact structure, zero leakage, and easy engine modification; the number of moving parts is reduced, the work is reliable, and the energy consumption is low. (c) It can be applied to overhead camshaft and bottom camshaft engines to expand the scope of application. (d) Drive components, brake components, slide valves, etc. can be designed as independent modules to improve the versatility and replaceability of components.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Figure 1 is a schematic diagram of an overhead camshaft type auxiliary braking mechanism.

FIG. 2 is a plan view of an overhead camshaft type auxiliary braking mechanism.

Figure 3 is a schematic diagram of the drive assembly.

FIG. 4 is a schematic diagram of the second transmission block.

Figure 5 is a schematic diagram of the slide valve.

Figure 6 is a schematic diagram of a bottom camshaft type auxiliary braking mechanism.

In the figure: A, fixing part; BC, brake control chamber; BT, brake oil drain chamber; DC, drive control chamber; CB1, exhaust brake cam; CD1, exhaust drive cam; CB2, intake brake Cam; CD2, intake drive cam; RB1, exhaust brake rocker arm; RD1, exhaust drive rocker arm; RB2, intake brake rocker arm; RD2, intake drive rocker arm; VB1, first exhaust valve assembly; VD1, second exhaust valve assembly; VB2, first intake valve assembly; VD2, second intake valve assembly; BA1, exhaust brake assembly; DA1, exhaust drive assembly; HV1, exhaust slide valve; BA2 , intake brake assembly; DA2, intake drive assembly; HV2, intake slide valve; BP11, exhaust brake upper piston; BP12, exhaust brake lower piston; BK1, exhaust brake spring; DP, drive Piston; DB, valve bridge; DK, drive spring; DLP, locking block; DLK, locking spring; DLB, transmission block; HVP, spool valve body; CV, check valve; HVK, spool valve spring; DLBI, second drive Block input; DLBO, the output of the second transmission block.

Detailed ways

The present invention relates to an auxiliary braking mechanism. FIG. 1 is a schematic diagram of an overhead camshaft type auxiliary braking mechanism, and the fixing member A is cut away. FIG. 2 is a top view of the overhead camshaft type auxiliary braking mechanism, and the fixing part A is hidden. The exhaust drive assembly DA1, the exhaust brake assembly BA1, the exhaust slide valve HV1, the intake drive assembly DA2, the intake brake assembly BA2 and the intake slide valve HV2 are all mounted on the fixing member A. The exhaust brake cam CB1 drives the first exhaust valve assembly VB1 through the exhaust brake rocker arm RB1, the exhaust brake assembly BA1 and the exhaust transmission block. After the exhaust drive cam CD1 passes through the exhaust drive rocker arm RD1 and the exhaust drive assembly DA1, it directly drives the second exhaust valve assembly VD1, and drives the first exhaust valve assembly VB1 through the exhaust transmission block. The intake brake cam CB2 drives the first intake valve assembly VB2 through the intake brake rocker arm RB2, the intake brake assembly BA2 and the intake transmission block. After the intake drive cam CD2 drives the rocker arm RD2 and the intake drive assembly DA2 through the intake air, it directly drives the second intake valve assembly VD2, and drives the first intake valve assembly VB2 through the intake transmission block. The fixing member A is further provided with a brake control chamber BC, a brake oil drain chamber BT and a drive control chamber DC, and the brake oil drain chamber BT is always in a low pressure state. The exhaust brake rocker spring RK1 provides spring force to drive the exhaust brake rocker RB1 to contact the exhaust brake cam CB1 at all times, and the intake brake rocker spring RK2 drives the intake brake rocker RB2 and the intake brake cam through the spring force. CB2 is always in touch.

Figure 3 is a schematic diagram of the drive assembly. The drive assembly includes a drive piston DP, a valve bridge DB, a drive spring DK, a locking block DLP and a locking spring DLK. The driving piston DP and the valve bridge DB are nested together, a driving spring DK is arranged between them, a locking hole is arranged on one of them, and a locking ring groove and a locking oil hole are arranged on the other. Two locking blocks DLP and a locking spring DLK are arranged in the locking hole, and the locking spring DLK is arranged between the two locking blocks DLP. The lock ring groove communicates with the drive control chamber DC through the lock oil hole. The drive rocker arm is in contact with the drive piston DP, the valve bridge DB directly drives the second valve assembly, and the valve bridge DB drives the first valve assembly through the transmission block DLB. When the drive control chamber DC is in a low pressure state, under the action of the locking spring DLK, the two locking blocks DLP will be in the locking hole and the locking ring groove at the same time, and the driving piston DP and the valve bridge DB will be locked into one, that is, the driving assembly is working. state, the motion of the drive cam will be transmitted to the two valves through the drive rocker arm and drive assembly. When the drive control chamber DC is in a high pressure state, the two locking blocks DLP are completely pressed into the locking holes, and the motions of the drive piston DP and the valve bridge DB are independent of each other, that is, the drive assembly is in a failed state, and the motion of the drive cam cannot be transmitted to the two valve. It can be seen from Fig. 1 that when the drive control chamber DC is in a low pressure state, the exhaust drive assembly DA1 and the intake drive assembly DA2 are in a working state; when the drive control chamber DC is in a high pressure state, the exhaust drive assembly DA1 and the intake drive assembly DA2 are in a working state. Failed state.

The brake assembly includes a brake spring, a lower brake piston and an upper brake piston. The brake rocker arm is in contact with the brake upper piston, and the brake lower piston drives the first valve assembly through the transmission block DLB.

Figure 5 is a schematic diagram of the slide valve. The spool valve includes a spool valve body HVP, a check valve CV and a spool valve spring HVK. 1, the exhaust slide valve HV1 controls the communication state between the oil chamber of the exhaust brake assembly BA1, the brake control chamber BC, and the brake oil drain chamber BT. When the brake control chamber BC is in a high pressure state, the exhaust slide valve HV1 goes down, the oil chamber of the exhaust brake assembly BA1 is not connected to the brake oil drain chamber BT, and the hydraulic oil in the brake control chamber BC passes through the one-way valve Enter the oil cavity of the exhaust brake assembly BA1, and the exhaust brake assembly BA1 is in working state. The movement of the exhaust brake cam CB1 will be transmitted to the first exhaust valve assembly VB1 through the exhaust brake rocker arm RB1, the exhaust brake assembly BA1 and the exhaust transmission block. When the brake control chamber BC is in a low pressure state, the exhaust spool valve HV1 goes up, the oil chamber of the exhaust brake assembly BA1 is not connected to the brake control chamber BC, and the oil chamber of the exhaust brake assembly BA1 is drained from the brake. The chamber BT is connected, the hydraulic oil in the brake control chamber BC leaks into the brake oil drain chamber BT, and the exhaust brake assembly BA1 is in a failed state. Movement of the exhaust brake cam CB1 cannot be transmitted to the first exhaust valve assembly VB1. Likewise, the intake spool valve HV2 controls the communication state of the oil chamber of the intake brake assembly BA2 with the brake control chamber BC and the brake drain chamber BT. When the brake control chamber BC is in a high pressure state, the intake brake assembly BA2 is in a working state; when the brake control chamber BC is in a low pressure state, the intake brake assembly BA2 is in a failure state.

When both the drive control chamber DC and the brake control chamber BC are in a low pressure state, the engine is in a four-stroke drive mode; when both the drive control chamber DC and the brake control chamber BC are in a high pressure state, the engine is in a two-stroke braking mode; when certain The drive control chamber DC corresponding to the cylinder is in a high pressure state, and when the brake control chamber BC is in a low pressure state, these cylinders are in a cylinder deactivation mode, and the state of the engine is determined by the working modes of other cylinders; the present invention provides the engine with low fuel consumption, low emission and high efficiency. The operation of the brakes provides the valve train.

The transmission block DLB includes a first transmission block or a second transmission block. Figure 3 uses the first transmission block. The first transmission block is slidably connected with the valve bridge DB, the valve bridge DB drives the first valve assembly through the ring platform of the first transmission block, and the lower brake piston drives the first valve assembly through the top end of the first transmission block. FIG. 4 is a schematic diagram of the second transmission block. The second transmission block is hinged with the valve bridge DB, the valve bridge DB drives the first valve assembly through the input end DLBI of the second transmission block, and the lower brake piston drives the first valve assembly through the output end DLBO of the second transmission block.

The drive assembly, brake assembly, slide valve, etc. in the present invention can be designed as independent modules, and all are integrated into the fixing part A, which has a compact structure, zero leakage, easy engine modification, universality and replaceability of parts. Except for the mode switching interval, the slide valve does not move; when the brake assembly fails, the brake assembly does not move; therefore, the number of moving parts of the present invention is reduced, the operation is reliable, and the energy consumption is low.

Figure 6 is a schematic diagram of a bottom camshaft type auxiliary braking mechanism. A cup and a push rod are arranged between the cam and the rocker arm. The present invention can be used for an overhead camshaft type engine and also can be used for a bottom mounted camshaft type engine, and the application scope of the present invention is wide.

Claims (6)

1. An auxiliary braking mechanism comprising a first valve assembly, a second valve assembly, a brake cam, a drive cam, a brake rocker arm, a drive rocker arm and a brake rocker spring on both its intake side and its exhaust side, It also includes a drive assembly, a brake assembly and a spool valve installed on the fixing member (A); the drive cam acts on the drive assembly through the drive rocker arm; it is characterized in that: the drive assembly includes a drive piston (DP), a valve bridge ( DB), driving spring (DK), locking block (DLP) and locking spring (DLK); the driving piston (DP) and the valve bridge (DB) are nested together with the driving spring (DK) set between them, two One of them is provided with a locking hole, and the other is provided with a locking ring groove and a locking oil hole; two locking blocks (DLP) and a locking spring (DLK) are arranged in the locking hole, and the locking spring (DLK) is arranged at the two positions. Between two locking blocks (DLP); the locking ring groove is communicated with the drive control chamber (DC) through the locking oil hole; the drive rocker arm is in contact with the drive piston (DP), and the valve bridge (DB) directly drives the second valve assembly, the valve The bridge (DB) drives the first valve assembly through the transmission block (DLB); the brake cam drives the first valve assembly through the brake rocker arm, the brake assembly, and the transmission block (DLB); the brake rocker arm spring provides spring force to drive the brake rocker arm Always in contact with the brake cam. 2. An auxiliary braking mechanism according to claim 1, wherein the braking assembly comprises a braking spring, a lower braking piston and an upper braking piston; the braking rocker arm is in contact with the upper braking piston, The lower brake piston drives the first valve assembly through a transmission block (DLB). 3 . The auxiliary braking mechanism according to claim 1 , wherein the spool valve comprises a spool valve body (HVP), a check valve (CV) and a spool valve spring (HVK). 4 . 4. An auxiliary braking mechanism according to claim 1, characterized in that: the transmission block (DLB) comprises a first transmission block or a second transmission block; the first transmission block and the valve bridge (DB) Sliding connection, the valve bridge (DB) drives the first valve assembly through the ring platform of the first transmission block, and the lower brake piston drives the first valve assembly through the top of the first transmission block; the second transmission block and the valve bridge (DB) ) hinged, the valve bridge (DB) drives the first valve assembly through the second transmission block input (DLBI), and the lower brake piston drives the first valve assembly through the second transmission block output (DLBO). 5 . The auxiliary braking mechanism according to claim 1 , wherein a cup and a push rod are arranged between the cam and the rocker arm. 6 . 6 . The control method of an auxiliary braking mechanism according to claim 1 , wherein the fixing member (A) is further provided with a brake control chamber (BC), a brake oil drain chamber (BT) and a brake control chamber (BC). The drive control chamber (DC) and the brake drain chamber (BT) are always in a low pressure state; in the drive mode, both the drive control chamber (DC) and the brake control chamber (BC) are in a low pressure state; in the brake mode, Both the drive control chamber (DC) and the brake control chamber (BC) are in high pressure state; in cylinder deactivation mode, the drive control chamber (DC) is in a high pressure state and the brake control chamber (BC) is in a low pressure state.

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