WO2012119282A1 - 一种压缩释放型发动机制动方法和装置 - Google Patents

一种压缩释放型发动机制动方法和装置 Download PDF

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Publication number
WO2012119282A1
WO2012119282A1 PCT/CN2011/001504 CN2011001504W WO2012119282A1 WO 2012119282 A1 WO2012119282 A1 WO 2012119282A1 CN 2011001504 W CN2011001504 W CN 2011001504W WO 2012119282 A1 WO2012119282 A1 WO 2012119282A1
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WO
WIPO (PCT)
Prior art keywords
brake
valve
piston
boss
main piston
Prior art date
Application number
PCT/CN2011/001504
Other languages
English (en)
French (fr)
Inventor
杨洲
Original Assignee
奚勇
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 奚勇 filed Critical 奚勇
Publication of WO2012119282A1 publication Critical patent/WO2012119282A1/zh

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/06Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12Transmitting gear between valve drive and valve
    • F01L1/18Rocking arms or levers
    • F01L1/181Centre pivot rocking arms
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/04Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation using engine as brake

Definitions

  • the present invention relates to the field of machinery, and more particularly to the field of valve actuation of vehicle engines, and more particularly to a compression release type engine braking method and apparatus.
  • Engine braking can be divided into compression release type braking and deflation type braking.
  • the engine's compression-release brake opens the exhaust valve at the end of the engine piston compression stroke and closes the exhaust valve during the early stages of the expansion stroke (typically before the exhaust valve opens normally).
  • a precedent for a compression-release brake is disclosed by Cummins in U.S. Patent No. 3,220,392, 1965.
  • the brake system passes the mechanical input through the hydraulic circuit to the exhaust valve to be opened.
  • the hydraulic circuit typically includes a primary piston that reciprocates within the primary piston bore from a mechanical input of the engine, such as the motion of the engine fuel injection cam or the movement of an adjacent exhaust cam.
  • the movement of the main piston is transmitted to the secondary piston on the hydraulic circuit by hydraulic fluid to reciprocate in the secondary piston bore, and the secondary piston acts directly or indirectly on the exhaust valve to generate valve movement of the engine brake operation.
  • the deflated brake of the engine is that the exhaust valve maintains a small amount of constant opening (partial periodic bleed brake) during a partial cycle, or during the period of the non-exhaust stroke (intake stroke, compression). Stroke, and expansion stroke) maintain a small amount of constant opening (full cycle bleed brake).
  • the main difference between partial cycle bleed brakes and full cycle bleed brakes is that the former does not open the exhaust valve during most of the intake stroke.
  • the inventors have provided related descriptions and examples for the deflated engine braking system and method in U.S. Patent No. 6,594,996.
  • the compression release type brake and the deflated type brake of the engine There are two main differences between the compression release type brake and the deflated type brake of the engine.
  • the first major difference is the difference in the opening phase (braking time) of the brake exhaust valve.
  • the brake exhaust valve of the full cycle bleeder brake is always open and therefore does not involve the opening time.
  • the opening time of the brake exhaust valve of the partial cycle bleed type brake is late in the intake stroke of the engine; and the opening time of the brake exhaust valve of the compression release type brake is at the later stage of the compression stroke of the engine, Partial cycle
  • the brake valve of the pneumatic brake is opened much later, so the load to be opened is much larger.
  • the second major difference is the difference in the opening height (brake valve lift) of the brake exhaust valve.
  • the brake valve of the brake valve of the deflated brake is approximately 0.5 to 1.0 mm (typically less than 1.0 mm), and the brake valve of the brake release valve of the compression release type brake is approximately 2.0 ⁇ 3.5mm (The brake valve of the hydraulic brake is generally more than 2.0imn).
  • the above differences lead to differences in design requirements and braking performance.
  • the compression release type brake power is greater than the bleed type brake, but the bleed type brake has a brake opening load that is much smaller than the compression release type brake.
  • the bleeder brake must be used in conjunction with an exhaust brake (such as an exhaust butterfly valve), while the compression release brake can be used alone (no exhaust brake required).
  • a precedent for the engine full cycle bleed brake system is disclosed by Muir in 1970 in U.S. Patent No. 3,525,317.
  • the brake system divides the engine brake into three gears.
  • the first gear is the brake generated by the friction loss caused by the engine and the moving parts of the vehicle.
  • the second gear is the full cycle bleed brake generated by keeping the exhaust valve of the engine continuously for a small amount of constant opening.
  • the third gear is to add an exhaust butterfly valve based on the full-cycle deflation brake of the second gear to generate a combined brake.
  • the engine partial cycle bleed brake system is disclosed in U.S. Patent No. 5,086, 838 to U.S.
  • the exhaust valve opens a small amount at the end of the engine intake stroke, then maintains a small amount of constant opening throughout the compression stroke, and finally closes in the early stage of the engine's expansion stroke.
  • engine bleeder brakes are used in conjunction with engine exhaust brakes (such as exhaust butterfly valves) to form a combined brake.
  • engine exhaust brakes such as exhaust butterfly valves
  • Using an exhaust butterfly valve or other exhaust restrictor to raise the exhaust back pressure may cause the exhaust valve to bounce or float (expand).
  • the engine industry generally disapproves of the float valve because the opening and closing of the exhaust valve is not driven by the cam when the valve is floated, and the seating speed of the valve cannot be controlled. Too large a valve seating speed may damage the engine.
  • U.S. Patent No. 4,848,289 issued to U.S. Patent No. 4,848,289, the disclosure of which is incorporated herein by reference.
  • a device and method for using a venting brake to increase the exhaust back pressure to cause a float valve When the exhaust back pressure is high enough, the exhaust valve floats or bounces near the end of the intake stroke. During the float of the exhaust valve, it is intervened with a brake device, that is, it is intercepted by a hydraulically controlled piston before the floating exhaust valve is closed, preventing it from closing, keeping it small The constant opening causes a partial cycle bleed brake (the exhaust valve closes after the exhaust stroke).
  • the brake system is an engine for a single exhaust valve per cylinder. 2006, Lamer
  • the reliability and durability of the above-mentioned deflated engine brake system of MAN face many problems because it relies on the intermittent opening or floating of the brake exhaust valve, which is inconsistent in time and size. .
  • the flying height of the exhaust valve is dependent on the exhaust back pressure, which is dependent on the engine speed and is affected by the quality and control of the exhaust brake and the design of the exhaust system.
  • the exhaust valve may not float enough or not, and the engine brakes will not start.
  • the demand for engine braking is high because the commercial vehicle engine runs at medium and low speeds most of the time.
  • excessive exhaust back pressure not only floats the braked exhaust valve, but also floats the exhaust valve that does not brake. The seating speed of the non-braking exhaust valve will be too large, affecting the reliability and durability of the engine.
  • the present inventors have disclosed a partial periodic deflation type braking device and method produced by cam driving in U.S. Patent No. 7,673,600 (Chinese Patent Application No. CN1991136A).
  • the main and secondary pistons are integrated in the valve bridge of the engine.
  • Brake The wheel is integrated with the engine's conventional exhaust cam, including a bleed-type brake boss.
  • the deflated brake boss begins to rise from the inner base circle of the cam at a later stage of the engine intake stroke.
  • valve bridge brakes are integrated into the valve bridge of the engine.
  • a precedent for the valve bridge brakes is disclosed by Calvin in U.S. Patent No. 3,520,287, issued toK.
  • the entire valve bridge is placed over a central guide.
  • the upper part of the guide rod acts as a brake piston, and the valve bridge slides along the brake piston through its internal piston bore.
  • valve bridge brake mechanism An improved valve bridge brake mechanism is disclosed by Sickler in U.S. Patent No. 4,572,114, issued to 1986.
  • a dedicated brake piston is placed in the upwardly open piston bore in the center of the valve bridge, which greatly reduces the relative movement between the brake piston and the wide bridge.
  • the valve bridge brake mechanism is used in a four-stroke engine, but produces two compression-release brakes per cycle.
  • a valve bridge brake device designed and manufactured by Hyundai Truck Company of the United States (JVS) (see U.S. Patent Publication No. US 20050211206, the inventor is one of the inventors of the patent application) in Scola ( Sickler's valve bridge brake mechanism adds a valve lift reset mechanism.
  • Scola Sickler's valve bridge brake mechanism adds a valve lift reset mechanism.
  • one to three pistons can be placed in the wide bridge to open one or two exhaust valves when braking.
  • the compression release type engine braking method solves the technical problem that the reliability and durability of the engine brake mechanism in the prior art are not good, the installation and commissioning are inconvenient, and the height and weight of the engine are increased.
  • the compression release type engine braking method of the present invention includes a process of opening an exhaust valve using an exhaust valve drive chain of an engine, the exhaust valve drive chain including a cam, a rocker arm and a valve bridge, the engine
  • the exhaust valve includes a first exhaust valve and a second exhaust valve, wherein the cam includes at least one brake boss, and the brake boss includes a rising from the inner base circle of the cam a rising section of the maximum lift and an equal height section maintaining the maximum lift, wherein the rocker arm is provided with an oil supply passage, wherein a main piston is disposed upwardly in the center of the valve bridge a hole, a secondary piston hole is arranged downwardly at one end of the valve bridge, a hydraulic passage is arranged between the main piston hole and the auxiliary piston hole, and a main piston is slidably disposed in the main piston hole, the main piston Having a projecting position and a retracting position relative to the main piston bore, a sub piston is slidably disposed in the counter piston bore, and the upper end of the
  • the oil supply passage and the one-way oil supply valve supply oil to the main piston hole, and the main piston is placed in the extended position, and the hydraulic passage between the main piston hole and the auxiliary piston hole is opened.
  • the rocker arm is driven by the rising section of the brake boss in the cam, so that the rocker arm pushes the main piston from the extended position to the retracted position, and the brake bracket is used to prevent the valve bridge from moving up, utilizing
  • the hydraulic pressure in the hydraulic passage transmits the motion of the main piston Giving the secondary piston, forcing the secondary piston to project downwardly in the secondary piston bore, opening the first exhaust valve, and then driving the rocker arm with the equal height section of the brake boss in the cam, placing the primary piston in the primary piston bore Keeping in the retracted position, blocking the main piston hole
  • the auxiliary piston is held in the extended position in the auxiliary piston hole to maintain the open state of the first exhaust valve, and the brake bracket is used to carry the
  • At least one oil discharge passage is disposed in one end of the valve bridge where the auxiliary piston hole is located, and the lower end of the oil discharge passage is communicated with the auxiliary piston hole, and the upper end of the oil discharge passage is closed by the lower end of the brake bracket. Opening.
  • a descending section is disposed on the braking boss, and a starting point of the descending section is connected to an end of the contour section, and an end point of the descending section is returned to or near an inner circle of the cam .
  • the rocker arm is used for the reverse movement to move the main piston from the retracted position to the extended position, and the hydraulic passage is opened in the main piston.
  • the opening in the hole opens the hydraulic pressure transmission between the main piston hole and the auxiliary piston hole, so that the sub piston moves to the retracted position under the force of the first exhaust valve.
  • the oil passage in the main piston is disposed along the axial direction of the main piston, and the lower end opening of the oil passage is disposed in the lower end end surface of the main piston.
  • an integrated exhaust boss is disposed on the cam
  • a step-up section is disposed on the brake boss, and a starting point of the step-up section is connected to an end of the contour section , the end point of the slow rise section is merged into the integrated exhaust boss, and the brake boss in the cam passes through the equal height section and enters the slow rise section, and is driven by the slow lift section of the brake boss
  • the rocker arm pushes the rocker arm downwardly through the main piston located in the retracted position of the main piston hole, so that the valve bridge end where the auxiliary piston hole is located is separated from the brake bracket located at the upper side thereof Opening the upper end of the oil discharge passage to unload the oil, reducing the hydraulic pressure in the auxiliary piston hole, so that the secondary piston moves upward in the secondary piston hole to the retracted position under the force of the first exhaust valve, so that the first exhaust The door moves up to the closed position.
  • the process of opening the exhaust valve by using an exhaust valve drive chain of the engine includes the following steps:
  • the main piston is built in the extended position of the main piston hole, and opens the hydraulic passage between the main piston hole and the auxiliary piston hole in the valve bridge.
  • the secondary piston is built in the retracted position of the secondary piston hole, and the first exhaust valve below the secondary piston is in the closed position.
  • the main piston is moved upward from the retracted position in the main piston hole of the valve bridge to the extended position, and the hydraulic passage between the main piston hole and the auxiliary piston hole is opened.
  • the first exhaust valve moves from the highest brake valve up position to the closed position.
  • the process of opening the exhaust valve by using an exhaust valve drive chain of the engine further includes the following steps:
  • the main piston when the main piston slides from the retracted position to the extended position in the main piston hole, the main piston is used to open the opening of the hydraulic passage located on the main piston hole, and the main piston slides from the extended position in the main piston hole. When retracting the position, the main piston is used to close the opening of the hydraulic passage located in the main piston bore.
  • oil discharge passage is provided with an outlet, and when the valve bridge is driven downward by the cam, the valve bridge is separated from the brake bracket, and the outlet of the oil discharge passage is opened.
  • the brake bracket is fixed to the engine, the brake bracket includes a connecting member, and the connecting member is located above the valve bridge.
  • the brake bracket is integrated on the rocker arm, the brake bracket includes a connecting piece, and the connecting member is located above the valve bridge.
  • the brake boss includes a compression release boss, and the compression release boss rises from the inner base circle of the cam at a later stage of the compression stroke of the engine, and is at the compression top dead center of the engine. The highest position is reached nearby, and falls back to the inner base circle of the cam in the early stage of the expansion stroke of the engine.
  • the brake boss includes a compression release boss and an exhaust gas recirculation boss, and the compression release boss rises from the inner base circle of the cam at a later stage of the compression stroke of the engine. And reaching the highest position near the compression top dead center of the engine, returning to the inner base circle of the convex 'wheel' in the early stage of the expansion stroke of the engine, the exhaust gas recirculation boss being at the late stage of the intake stroke of the engine It rises from the inner base circle of the cam and falls back to the inner base circle of the cam in the early stage of the compression stroke of the engine.
  • an integrated exhaust boss is disposed on the cam
  • the brake boss includes a compression release boss
  • the compression release boss is in a compression stroke of the engine
  • the latter rises from the inner base circle of the cam and rises to the highest position before the top dead center of the compression stroke of the engine, maintaining the highest position during the remainder of the compression stroke of the engine and the initial stage of the expansion stroke of the engine.
  • the remaining period of the expansion stroke drops back to the inner base circle of the cam or into the integrated exhaust boss, which consists of the bottom and the top, the bottom of the integrated exhaust boss and the brake
  • the boss is near the same height, and the top of the integrated exhaust boss is nearly identical to the conventional boss of the engine.
  • the brake boss includes an exhaust gas recirculation boss, and the exhaust gas recirculation boss rises from the inner base circle of the cam at a later stage of the intake stroke of the engine, and compresses the engine. The early stage of the stroke drops back to the inner base circle of the cam.
  • an integrated exhaust boss is disposed on the cam, the brake boss includes a compression release boss, and the compression release boss is in the second half of the compression stroke of the engine.
  • the inner base circle of the cam begins to rise and rises to the highest position before the compression top dead center of the engine, maintaining the highest position during the remainder of the compression stroke of the engine and the expansion stroke of the engine, in the expansion stroke of the engine The remaining period rises into the integrated exhaust boss.
  • a preload spring is used to maintain an exhaust valve drive chain brake gap generated by the retracted position and the extended position of the main piston inside the exhaust valve drive chain, and the exhaust brake is used to drive the chain brake gap. Eliminate the non-following and impact inside the exhaust valve drive chain.
  • the present invention also provides a compression release type engine brake device including a brake control mechanism and a brake drive mechanism, wherein the brake control mechanism includes a control valve connected to the hydraulic generating device, the brake driving mechanism comprises a brake box body, an oil supply mechanism, a oil discharge mechanism and a brake cam, wherein the brake box body is provided with a main piston hole and a secondary piston hole, A communication hydraulic passage is disposed between the main piston hole and the auxiliary piston hole, a main piston is slidably disposed in the main piston hole, and a sub piston is slidably disposed in the sub piston hole, and the oil supply mechanism is The oil supply passage and the one-way oil supply valve are included, wherein the control valve in the brake control mechanism is connected to the inlet of the oil supply passage, the outlet of the oil supply passage and the main piston hole Connecting, the one-way oil supply valve is disposed between the oil supply passage or the oil supply passage and the main piston hole, and the oil supply direction of the one-way oil supply valve is from the oil supply passage into the main piston
  • the brake box body is composed of a valve bridge, the main piston hole is disposed in an upward opening of the center of the valve bridge, and the auxiliary piston hole is disposed at one end of the valve bridge
  • the hydraulic passage is disposed in the valve bridge and communicates with the main piston hole and the auxiliary piston hole
  • the main piston is disposed in the main piston hole
  • the auxiliary piston is disposed in the auxiliary piston hole
  • the main piston The upper end is fixedly connected with the rocker arm of the engine, the rocker arm is provided with an oil supply passage, and an oil passage is disposed in the main piston, and the upper end of the oil passage and the oil supply passage in the rocker arm
  • the lower end of the oil passage communicates with the main piston hole
  • the one-way oil supply valve is disposed between the main piston hole and the oil supply passage or within the oil supply passage
  • a brake bracket is disposed from the oil supply passage to the main piston hole, and the upper side of the valve bridge where the
  • the lower end of the secondary piston is connected to a first exhaust valve in the engine exhaust valve, and the lower side of the other end of the valve bridge is connected to a second exhaust valve in the engine exhaust valve.
  • the brake bracket is fixed on the engine, the brake bracket includes a connecting member, and the connecting member is located above the valve bridge.
  • the brake bracket is integrated on the rocker arm, the brake bracket includes a connector, and the connecting member is located above the valve bridge.
  • the connecting portion of the brake bracket includes a transition piston, the transition piston is slidably disposed in a transition piston bore of the wide bridge, and the transition piston hole is located above the secondary piston bore.
  • the brake boss includes a compression release boss, and the compression The release boss rises from the inner base circle of the cam at a later stage of the compression stroke of the engine and reaches a highest position near the compression top dead center of the engine, and descends to or near the inner base circle of the cam in the early stage of the expansion stroke of the engine.
  • the brake boss includes a compression release boss and an exhaust gas recirculation boss, and the compression release boss rises from the inner base circle of the cam at a later stage of the compression stroke of the engine. And reaching a highest position near the compression top dead center of the engine, falling back to or near the inner base circle of the cam in the early stage of the expansion stroke of the engine, the exhaust gas recirculation boss being at a later stage of the intake stroke of the engine The inner base circle of the cam begins to rise and falls back to the inner base circle of the cam in the early stage of the compression stroke of the engine.
  • an integrated exhaust boss is disposed on the cam, the brake boss includes a compression release boss, and the compression release boss is at a later stage of the compression stroke of the engine.
  • the inner base circle of the cam begins to rise and rises to the highest position before the top dead center of the compression stroke of the engine, maintaining the highest position during the remainder of the compression stroke of the engine and the initial stage of the expansion stroke of the engine, in the expansion of the engine
  • the remainder of the stroke drops back to the inner base circle of the cam or into the integrated exhaust boss, which consists of the bottom and the top, the bottom of the integrated exhaust boss and the brake boss Near the same height, the top of the integrated exhaust boss is nearly identical to the conventional boss of the engine.
  • the brake boss includes an exhaust gas recirculation boss, and the exhaust gas recirculation boss rises from the inner base circle of the cam at a later stage of the intake stroke of the engine, and compresses the engine. The early stage of the stroke drops back to the inner base circle of the cam.
  • an integrated exhaust boss is disposed on the cam
  • the brake boss includes a compression release boss
  • the compression release boss is in the second half of the compression stroke of the engine. Starting from the inner base circle of the cam and rising to the highest position before the compression top dead center of the engine, maintaining the highest position during the remaining period of the compression stroke of the engine and the expansion stroke of the engine, in the expansion stroke of the engine The remaining period rises into the integrated exhaust boss.
  • a preloading spring is disposed in the brake driving mechanism.
  • one end of the pretensioning spring is disposed on the engine, and one end of the pretensioning spring acts on one end of the rocker arm.
  • an automatic gap compensation mechanism is disposed in the brake driving mechanism.
  • the working principle of the present invention is: When the engine brake is required, the brake control mechanism is opened to supply oil to the brake drive mechanism.
  • the low-pressure oil engine lubricating oil
  • the brake boss of the cam rises from the inner base circle, and the rocker arm drives the main piston in the valve bridge to move downward from the extended position to the retracted position of the bottom surface of the main piston hole, and the downward movement of the main piston is transmitted to the hydraulic passage through the hydraulic passage Secondary piston.
  • a brake bracket located above the valve bridge above the secondary piston bore prevents the valve bridge from rising due to oil pressure in the secondary piston bore.
  • the secondary piston in the secondary piston bore of the valve bridge projects downwardly, opening the brake exhaust valve located below the secondary piston.
  • the cam enters the highest lift of the brake boss, and the main piston reaches the retracted position of the bottom of the hole in the main piston hole of the valve bridge, blocks the inlet of the hydraulic passage, and closes the hydraulic passage between the main piston hole and the auxiliary piston hole. .
  • the secondary piston reaches the extended position in the secondary piston bore of the valve bridge, and the exhaust valve below the secondary piston is kept open for a gap.
  • the brake load on the secondary piston cannot be transmitted to the primary piston through the hydraulic passage and can only be transmitted through the valve bridge to the brake bracket above the valve bridge above the secondary piston bore.
  • the main piston and exhaust valve actuators (including the rocker arm and cam, etc.) are not subjected to the braking load.
  • the integrated exhaust boss of the cam rises from the inner base circle, and the rocker arm drives the main piston in the valve bridge to move downward from the extended position to the retracted position of the bottom surface of the main piston hole, and the downward movement of the main piston passes through the hydraulic passage Passed to the secondary piston.
  • a brake bracket located above the valve bridge above the secondary piston bore prevents the valve bridge from rising due to oil pressure in the secondary piston bore.
  • the secondary piston in the secondary piston bore of the valve bridge extends downward, opening The brake exhaust valve below the secondary piston.
  • the cam enters the top of the integrated exhaust boss, and the primary piston presses the bottom of the primary piston bore, driving the valve bridge to move downward.
  • the valve bridge is separated from the brake bracket located thereon, and the oil discharge passage above the secondary piston hole in the valve bridge is opened to discharge oil, and the secondary piston is moved from the extended position to the retracted position from the auxiliary piston hole of the valve bridge.
  • the valve bridge transmits the motion of the top of the integrated exhaust boss to the two exhaust valves, creating a conventional exhaust valve motion. .
  • the effect of the present invention is positive and significant compared to the prior art.
  • the invention integrates the compression release type braking mechanism into the existing valve driving chain of the engine, and utilizes the brake bracket to bear the braking load and reset the brake valve lift, and has the advantages of simple design, compact structure and reduced engine braking.
  • the load increases the braking power of the engine and improves the reliability and durability of the engine operation.
  • Figure 1 is a schematic view showing the first embodiment of the compression-release type engine brake apparatus of the present invention in which the cam is at the inner base circle position during braking.
  • Fig. 2 is a view showing the first embodiment of the compression-release type engine brake apparatus of the present invention in which the cam is at the highest position of the brake boss during braking.
  • Fig. 3 is a schematic view showing the brake control mechanism of the compression release type engine brake device in the "on" position in the present invention.
  • Fig. 4 is a view showing the brake control mechanism of the compression release type engine brake device in the "OFF" position in the present invention.
  • Fig. 5 is a schematic view showing a cam profile of the compression release type engine brake device of the present invention.
  • Fig. 6 is a view showing an exhaust valve lift curve and an intake valve lift curve of the compression release type engine brake device of the present invention.
  • Fig. 7 is a view showing still another cam profile of the compression release type engine brake device of the present invention.
  • Fig. 8 is a schematic view showing still another cam profile of the compression release type engine brake device of the present invention.
  • Fig. 9 is a view showing the second embodiment of the compression-release type engine brake device of the present invention in which the cam is at the inner base circle position when not braking.
  • Fig. 10 is a view showing the second embodiment of the compression-release type engine brake apparatus of the present invention in which the cam is at the inner base circle position during braking.
  • the first embodiment of the compression-release type engine brake apparatus of the present invention is in the position of the inner base circle 225 and the highest lift position of the brake boss at the time of braking.
  • the three main components are included in Figures 1 and 2: an exhaust valve actuator 200, an exhaust valve 300 (including a first exhaust valve 3001 and a second exhaust valve 3002), and an engine brake drive mechanism 100.
  • the exhaust valve actuator 200 includes a cam 230, a cam follower 235, a rocker arm 210, and a valve bridge 400.
  • the combination of the exhaust valve actuator 200 and the exhaust valve 300 may be referred to as an exhaust valve drive train.
  • a valve clearance adjustment system is typically provided at one end of the rocker arm 210 (on the side of the valve bridge 400 or on the side adjacent the cam 230).
  • the valve clearance adjusting system in this embodiment is constituted by a valve clearance adjusting screw 110 disposed on the side of the valve bridge 400, and the valve clearance adjusting screw 110 is located on the rocker arm 210 and fixed by the locking nut 105.
  • a valve clearance adjusting screw 110 is coupled to the foot pad 114.
  • the rocker arm 210 is swingably mounted on the rocker shaft 205.
  • the first exhaust valve 3001 and the second exhaust valve 3002 are respectively placed on the valve seat 320 in the engine block 500 by a valve spring 3101 and a valve spring 3102 (referred to as a valve spring 310), respectively, to block gas (when the engine is braked) Air)
  • a valve spring 3101 and a valve spring 3102 referred to as a valve spring 310
  • Air Air
  • the exhaust valve actuator 200 transmits the mechanical movement of the cam 230 through the valve bridge 400 to the first exhaust valve 3001 and the second exhaust valve 3002 to periodically open and close.
  • the brake drive mechanism 100 includes a brake case, a brake bracket, and a brake cam.
  • the brake case in this embodiment employs a valve bridge 400 of the engine.
  • the central opening of the valve bridge 400 is provided with a main piston hole 415, and one end of the valve bridge 400 is provided with a sub-piston hole 190 downwardly.
  • Main piston bore 415 and secondary piston bore 190 are connected by a hydraulic passage 412.
  • the main piston hole 415 is also passed through a single
  • the oil supply valve 172 is connected to the oil supply passage 115 above it.
  • a main piston 162 and a sub piston (also called a brake piston) 160 are slidably disposed in the main piston hole 415 and the sub piston hole 190, respectively.
  • the upper surface of the main piston 162 is subjected to the action from the rocker arm 210.
  • the lower surface of the secondary piston 160 is connected to the first exhaust valve 3001 for braking of the engine.
  • the underside of the other end of the valve bridge 400 is coupled to a non-braking second exhaust valve 3002 of the engine.
  • An oil discharge passage 197 is disposed in the valve bridge 400 above the auxiliary piston hole 190.
  • the oil discharge passage 197 communicates with the secondary piston hole 190, and a brake bracket 125 is disposed above the oil discharge passage 197.
  • Brake bracket 125 includes adjustable connectors 1052 and 1142 and fasteners 1102. The brake bracket 125 can be fixed to the engine.
  • the brake bracket 125 (via the connector) is located on the valve bridge 400 above the secondary piston bore 190 and closes the outlet of the oil discharge passage 197.
  • the brake cam is integrated with a conventional cam of the engine, and the integrated cam 230 includes at least one brake boss and an integrated exhaust boss 220.
  • the brake boss of the cam 230 herein includes a compression relief boss 233 and an exhaust gas recirculation boss 232 on the inner base circle 225.
  • a preload spring 198 can be placed between the exhaust rocker arm 210 and the engine.
  • the pretension spring 198 is a leaf spring, one end of which is disposed on the brake bracket 125 and the other end of which is disposed on the rocker arm 210.
  • the pretension spring 198 can be a coil spring and other forms of spring.
  • the preload springs 198 can also be mounted in different locations, such as between the primary piston 162 and the valve bridge 400, between the cam 230 (or the push rod of the pusher engine) and the rocker arm 210.
  • the pretension spring 198 maintains a brake gap 234 generated by the retracted position (Fig. 2) of the main piston 162 and the extended position (Fig. 1) inside the exhaust valve drive train (this gap may be at the cam 230 when not braking)
  • the inner base circle 225 and the cam follower wheel 235) eliminate the non-following and impact inside the exhaust valve drive chain.
  • a positioning pin 137 is disposed in the valve bridge 400, and a limiting groove 142 is disposed on the secondary piston 160 to form a piston limiting mechanism to limit the maximum stroke of the secondary piston 160.
  • a spring 177 may be disposed between the secondary piston 160 and the valve bridge 400.
  • a pressure relief mechanism is also disposed in the valve bridge 400.
  • the pressure relief mechanism includes a pressure relief hole 152 on the secondary piston 160.
  • the brake control mechanism 50 When engine braking is required, as shown in Figure 3, the brake control mechanism 50 is opened. Oil is supplied to the brake drive mechanism 100 via the brake fluid network.
  • the brake fluid network includes a plurality of oil supply passages, such as an axial bore 211 and a radial bore 212 in the rocker shaft 205, a slit 213 in the rocker arm 210, and an oil hole 214 and a transverse bore 113 in the valve gap adjustment screw. And a vertical hole 115 (in communication with a hole in the foot pad 114).
  • the low pressure oil is supplied from the oil supply passage to the main piston bore 415 through a one-way oil supply valve 172 provided on the main piston 162.
  • the primary piston 162 is in the extended position shown in FIG.
  • the engine's lube line is not shown here.
  • the lubricating oil passage can also be combined with the brake oil passage, and two different oil pressures are used for oil supply.
  • Low oil pressure is used for lubrication, for example, one bar or lower; high oil pressure is used for braking, for example, two bars or higher.
  • the rocker arm 210 drives the main piston 162 in the valve bridge 400 to move downward from the extended position of FIG. 1 toward the main piston hole.
  • the retracted position of the bottom surface 446 transmits the downward movement of the primary piston 162 to the secondary piston 160 through the hydraulic passage 412 between the primary piston bore 415 and the secondary piston bore 190.
  • the brake bracket 125 on the valve bridge 400 above the secondary piston bore 190 prevents the valve bridge 400 from rising due to the oil pressure in the secondary piston bore 190.
  • the secondary piston 160 in the secondary piston bore 190 of the valve bridge 400 can only project downwardly, opening the brake first exhaust valve 3001 located below the secondary piston 160.
  • the braking load on the secondary piston 160 cannot be transmitted to the primary piston 162 through the hydraulic passage 412, and can only be transmitted through the valve bridge 400 to the brake bracket 125 on the valve bridge 400 above the secondary piston bore 190.
  • the primary piston 162 and the exhaust valve actuator 200 (including the rocker arm 210 and the cam 230) are not subjected to braking loads.
  • the cam 230 descends from the highest lift of the brake boss 233, the main piston 162 moves upward from the retracted position in the main piston bore 415 of the valve bridge 400 to the extended position, opening the main piston bore 415 and the secondary piston bore.
  • the hydraulic passage 412 between 190, the secondary piston 160 in the secondary piston bore 190 moves upward with the primary piston 162.
  • the secondary piston 160 is returned to the retracted position within the secondary piston bore 190 of the wide bridge 400 (Fig. 1).
  • the rocker arm 210 drives the main piston 162 in the valve bridge 400 to move downward from the extended position of FIG. 1 toward the bottom surface 446 of the main piston bore.
  • the downward movement of the primary piston 162 is transmitted to the secondary piston 160 through the hydraulic passage 412 between the primary piston bore 415 and the secondary piston bore 190.
  • the brake bracket 125 on the valve bridge 400 above the secondary piston bore 190 does not rise due to the oil pressure in the secondary piston bore 190.
  • the secondary piston 160 in the secondary piston bore 190 of the valve bridge 400 can only project downwardly, opening the first exhaust valve 3001 located below the secondary piston 160.
  • the primary piston 162 presses the primary piston bore 446, driving the valve bridge 400 downward.
  • the valve bridge 400 is separated from the brake bracket 125 located thereon, and the oil discharge passage 197 in the valve bridge 400 communicating with the auxiliary piston hole 190 is opened to discharge oil, and the auxiliary piston 160 is extended from the auxiliary piston hole 190 of the valve bridge 400.
  • the valve bridge 400 transmits the motion of the top of the integrated exhaust boss 220 to the first exhaust valve 3001 and the second exhaust valve 3002 to produce conventional exhaust valve motion.
  • the brake boss of the cam 230 further includes an exhaust gas recirculation boss 232
  • the exhaust gas recirculation boss 232 opens the first exhaust valve 3001 through the exhaust valve drive chain, and the above-described compression release boss The process of opening the first exhaust valve 3001 through the exhaust valve drive chain is the same, and is not here. Repeat again. If the engine has sufficient exhaust back pressure, the braking power of the engine may be further improved after the exhaust recirculation boss 232 is added.
  • the valve bridge 400 transmits the motion of the top of the integrated exhaust boss 220 to the first exhaust valve 3001 and the second exhaust valve 3002 to produce conventional exhaust valve motion.
  • the secondary piston 160 remains in the retracted position shown in Figure 1 (due to the upward force of the exhaust valve spring 3101)
  • the primary piston 162 is held in the retracted position shown in FIG. 2 (due to the downward force of the pretension spring 198), a gap is formed between the cam follower wheel 235 on the rocker arm 210 and the inner base circle 225 of the cam 230.
  • the brake control mechanism 50 of the compression release type engine brake device of the present invention is in the "on" and “off” positions.
  • the solenoid valve 51 in the figure is a two-position three-way type.
  • the brake control mechanism 50 is opened (Fig. 3)
  • the valve body of the electromagnetic width 51 opens the oil supply port 111 downward, and at the same time, the oil discharge port 222 is closed, and the low-pressure oil (lubricating oil) of the engine flows from the brake fluid passage to the brake.
  • Drive mechanism 100 (Figs. 1 and 2).
  • the brake control mechanism 50 is closed (Fig.
  • the valve body of the solenoid valve 51 closes the oil supply port 111 upward, and at the same time, the oil discharge port 222 is opened, and the low-pressure oil (lubricating oil) of the engine stops flowing to the brake drive mechanism 100 (Fig. 1 and 2), the brake drive mechanism 100 instead unloads oil from the brake fluid passage and the oil discharge port 222.
  • the auxiliary piston hole 190 in the valve bridge 400 is provided with an oil discharge passage 197 (Figs. 1 and 2), it is entirely possible to use two-position double power supply.
  • the magnetic valve that is, does not require the oil discharge port 222.
  • Figure 5 is a view showing a cam profile in the compression release type engine brake device of the present invention, including a brake boss and an integrated exhaust boss 220, the brake boss including a compression release boss 233 and a row Gas recirculation boss 232.
  • the compression release boss 233 includes three sections: a rising section "A”, a contour section "B”, and a falling section “C”.
  • the ascending section “A” rises from the inner base circle 225 of the cam to the highest lift of the brake.
  • the contour "B” keeps the maximum lift of the brakes constant for a period of time.
  • the descending section “C” drops from the highest lift of the brake to the inner base circle 225 of the cam.
  • the function of the contour section "B" is to maintain the primary piston 162 in the retracted position of the bore bottom 446 in the main piston bore 415 of the bridge 400 during braking (Fig. 2), closing the primary piston bore 415 and the secondary piston bore 190.
  • the brake load on the secondary piston 160 cannot be transmitted to the primary piston 162 through the hydraulic passage 412, and can only be transmitted through the valve bridge 400 to the brake bracket 125 located thereon.
  • the exhaust valve actuator 200 (including the rocker arm 210 and the cam 230) is not subjected to the braking load, reducing the force and wear of the exhaust valve actuator 200, increasing the reliability and durability of the engine.
  • the exhaust gas recirculation boss 232 can also be designed to compress the shape of the relief boss 233. However, due to the exhaust gas recirculation, the force of the exhaust valve is much less than during the compression release period. Therefore, the contour shape of the exhaust gas recirculation boss 232 can be designed without regard to the influence of the load.
  • the integrated exhaust boss 220 is divided into a bottom and a top (the two-dot chain line in Figure 5 separates them).
  • the bottom of the integrated exhaust boss 220 is a transition portion that is approximately the same height as the brake boss; the top of the integrated exhaust boss 220 is approximately the same as the conventional boss of the engine.
  • the bottom of the integrated exhaust boss 220 together with the brake bosses are moved by the exhaust valve.
  • the gap 234 (Fig. 1) inside the drive chain is skipped or lost and is not transmitted to the exhaust valve 300; only the movement of the top of the integrated exhaust boss 220 is transmitted to the exhaust valve 300, resulting in a conventional valve lift motion.
  • Fig. 6 is a view showing a lift curve of an exhaust valve and a lift curve of an intake valve in the compression release type engine brake device of the present invention.
  • the conventional wide-lift curve 220m of the engine exhaust valve has a starting point of 225a, an ending point of 225b, and a maximum lift of approximately 220b.
  • the secondary piston in the valve bridge 400 There is no oil discharge passage 197 on the hole 190 (Figs. 1 and 2), then the starting point of the enlarged main valve rise curve 220v generated by the enlarged conventional exhaust boss 220 during engine braking is 225h, and the end point is 225c.
  • Its highest lift 220e is the sum of 220a and 220b.
  • the wide curve of the brake exhaust valve 3001 transitions to the main valve rise curve 220m at the transition point 220t between the bottom 220a and the top portion 220b of the enlarged main valve lift curve 220v, at 220s and the main point
  • the valve lift curve 220m merges and closes early when the end point 225b is lower than the unloading channel.
  • the starting point of the exhaust valve recirculation brake valve 232v is 225d, which is located at the end of the intake stroke of the engine, that is, when the valve lift curve 280v of the intake valve tends to close; the brake valve of the exhaust gas recirculation rises
  • the end point of the 232v is 225e, which is located in the early stage of the compression stroke of the engine.
  • the compression-released brake valve liter 233v starts at 225f and is located at the end of the engine's compression stroke; the compression-released brake valve 233v ends at 225g, which is located in the early stage of the engine's expansion stroke.
  • the valve lift curve is cycled between 0 and 720 °, with 0° and 720 ° being the same point.
  • the valve bridge 400 is separated from the brake bracket 125, the oil discharge passage 197 is opened to discharge the oil, the secondary piston 160 is moved from the extended position to the retracted position, and the valve lift curve of the brake exhaust valve 3001 is raised from the transition point 220t to the main valve.
  • the 220m transition (Fig. 6), finally closed at the end point 225b, is much ahead of the end point 225c when there is no unloading channel. This reduces the lift of the exhaust valve at the top dead center position of the engine exhaust stroke, avoids the collision of the exhaust valve with the piston, increases the braking power, and lowers the temperature inside the cylinder.
  • Fig. 7 shows another cam profile of the compression release type engine brake device of the present invention. This cam profile differs from the cam profile shown in FIG.
  • the first two portions of the compression release boss 233 also include the ascending section "A” and the contour section "B", but the descending section “D” after the contour section "B” does not fall to the inner base circle 225, but transitions The integrated exhaust boss 220 is merged.
  • Fig. 8 shows still another cam profile of the compression release type engine brake device of the present invention.
  • This cam profile is also distinguished from the cam profile shown in FIG. 5 by the compression release boss 233.
  • the first two parts of the compression release boss 233 also include the ascending section "A” and the equal section “B”, but do not descend after the contour section "B”, but pass through a ramp section "E”, into the integration Exhaust boss 220 ⁇
  • the cam 230 enters the retarding section " ⁇ " from the equal section " ⁇ ” of the brake boss, and the main piston 160 pushes the valve bridge downward from the retracted position of the main piston hole bottom 446 of the valve bridge 400. 400 (Fig.
  • valve bridge 400 is separated from the brake bracket 125 on the valve bridge 400, the oil discharge passage 197 in the valve bridge 400 above the secondary piston bore 190 is opened to discharge oil, and the secondary piston 160 is at the secondary piston of the valve bridge 400.
  • the hole 190 is moved upward to the retracted position, and the exhaust valve 3001 below the secondary piston 160 is closed upward. That is to say, the unloading passage 197 on the sub-piston hole 190 in the valve bridge 400 will be opened in the retarding section " ⁇ ", and the brake valve of the brake exhaust valve 3001 may rise from the highest valve to zero ( shut down).
  • the second embodiment of the compression-release type engine brake apparatus of the present invention is in the position of the inner base circle at the time of non-braking and braking.
  • the difference between this embodiment and the first embodiment is that this embodiment employs a different brake bracket 125.
  • the brake bracket 125 located above the valve bridge 400 has two main functions: one is to support the valve bridge 400 when the engine is braked, to prevent or limit the upward movement of the valve bridge 400, and to close the oil discharge passage above the secondary piston hole 190.
  • the brake bracket 125 of the present embodiment also includes other connecting members such as the transition piston 161.
  • the transition piston 161 is slidably disposed within the transition piston bore 191 above the valve bridge 400 to form an automatic clearance compensation mechanism.
  • the oil discharge passage 197 is connected to the secondary piston hole 190 above the secondary piston hole 190 (the size of the two piston holes is determined as needed, and the sizes thereof are not necessarily the same).
  • An oil discharge passage 196 is added to the transition piston 161.
  • the range of movement of the transition piston 161 is controlled by the pressure piece 178.
  • the pressing piece 178 is fixed to the valve bridge 400 by a screw 179.
  • the range of movement of the transition piston 161 can also be controlled by other means such as a snap ring or the like.
  • the upper surface of the transition piston 161 is connected to the other connector of the brake bracket 125 like the foot pad 1 142.
  • the foot pad 1 142 is placed on the ball of the pressure ball 1103.
  • the pressure ball 1103 can also be combined with the adjustment screw 1102.
  • the brake control mechanism 50 is closed to stop the supply of oil to the brake drive mechanism 100, and the brake device is in the non-braking state as shown in Fig. 9.
  • the main piston hole 415 and the sub-piston hole 190 are in a drain state due to the oil discharge mechanism.
  • the primary piston 162 is pressed against the bottom surface 446 of the primary piston bore 415 by the biasing spring 198, and a gap 134 is formed between the cam follower 235 and the inner base circle 225 of the cam 230.
  • the secondary piston 160 is pressed against the retracted position of the bottom surface of the secondary piston bore 190, and the exhaust valve 3001 below the secondary piston 160 is in the closed position.
  • the transition piston 161 of the brake bracket 125 is pressed against the retracted position of the bottom surface of the transition piston bore 191 by the action of the spring 177.
  • the cam 230 enters the brake boss 232 or the brake boss 233 from the inner base circle 225, due to the gap 134 inside the exhaust valve drive chain (between the cam follower wheel 235 and the cam 230), the brake boss 232 or The movement of the brake boss 233 is skipped or lost and is not transmitted to the exhaust valve 300.
  • the cam 230 enters the top of the integrated exhaust boss 220 (Figs. 5, 7 and 8)
  • the movement of the cam is transmitted in a mechanically fixed manner by the rocker arm 210, the primary piston 162, the valve bridge 400 and the secondary piston 160.
  • the exhaust valve 300 (the first exhaust valve 3001 and the second exhaust valve 3002) is given a conventional exhaust valve motion.
  • the brake control mechanism 50 is turned on to supply oil to the brake drive mechanism 100.
  • the brake device enters the braking state as shown in FIG. 10 from the non-braking state as shown in FIG.
  • the low pressure oil enters the main piston bore 415 from the oil supply passage through the oil supply check valve 172.
  • the main piston 162 moves upward from the retracted position of the bottom surface 446 of the main piston hole 415 of the valve bridge 400 to the extended position under the action of oil pressure, and pushes the rocker arm 210 to rotate clockwise until the cam follower wheel 235 and the cam 230 are inside.
  • the base circle 255 is in contact.
  • a main brake 234 is formed between the main piston 162 and the bottom surface 446 of the main piston hole 415 (that is, the valve bridge 400) (corresponding to the gap 134 of FIG. 9), and the main piston hole 415 and the sub-piston hole are opened.
  • the oil flows into the secondary piston bore 190 and the transition piston bore 191 above it.
  • the oil pressure overcomes the force of the spring 177, pushing the transition piston 161 upward against the foot pad 1142, closing the oil discharge passage, and preventing the oil in the transition piston hole 191 and the secondary piston hole 190 from leaking upward.
  • the above description discloses a new compression release type engine brake apparatus and method.
  • the above-described embodiments are not to be considered as limiting the scope of the invention, but rather as some specific examples of the invention, many other variations are possible.
  • the compression-release engine brakes and methods herein can be used not only for overhead cam engines but also for push-rod engines.
  • the one-way fuel supply valve 172 can take different forms, such as a ball valve, a disc valve, and the like.
  • the one-way fuel supply valve 172 can also be placed in a different position, such as within the primary piston 162.
  • the one-way oil supply valve 172 can also be disposed in the oil supply passage above the main piston 162, such as the rocker arm 210. Inside the oil gallery 214.
  • the one-way oil supply valve 172 only allows the oil flow to enter the main piston bore 415 below the main piston 162 from its upstream oil supply passage in one direction.
  • other types of oil discharge ports may be used.
  • the oil discharge valve of the oil discharge mechanism is in a closed state when the brake boss pushes the main piston 162 to slide relative to each other in the brake body. When the top of the integrated exhaust boss further pushes the main piston 162 to move, the unloading valve of the oil discharge mechanism opens and unloads the oil.
  • the main piston 162, the sub piston 160, and the transition piston 161 may take different forms, such as "H" type and "T” type, etc.; the exhaust valve of the brake may be the first exhaust valve 3001, or The second exhaust valve 3002.
  • the brake bracket 125 can be mounted in a variety of forms, in addition to being fixed to different components and positions of the engine, or integrated into the moving parts of the engine.
  • the brake bracket 125 of the second embodiment can be integrated on the rocker arm 210.
  • the secondary piston 160 is located on the second exhaust valve 3002.
  • the transition piston 161 functions as a second main piston in addition to the clearance compensation. That is, during braking, the elephant foot 14 14 on the rocker arm 210 pushes the main piston 162, while the elephant foot 1 142 of the brake bracket 125 on the rocker arm 210 pushes the transition piston 161. Then, the main piston 162 and the transition piston 161 push the secondary piston 160 together by the hydraulic link to open the second exhaust valve 3002.
  • the connection of the brake bracket 125 can also be selected in different styles, or different sealing measures, such as adding seals, to ensure the sealing of the oil discharge passage.
  • the manner in which the primary piston 162 blocks the inlet 472 of the hydraulic passage 412 may be different.
  • the inlet 472 of the hydraulic passage 412 is designed to be below the primary piston 162 (rather than the side).
  • the primary piston 162 is moved to the retracted position of the primary piston bore bottom surface 446, the bottom surface of the primary piston 162 covers the inlet 472.
  • valve bridge 400 As the brake case, other forms may be used in addition to the valve bridge 400 as the brake case.
  • an overhead brake case that is fixed to the engine. Therefore, the scope of the invention should not be determined by the specific examples described above, but by the claims.

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Description

一种压缩释放型发动机制动方法和装置
技术领域
本发明涉及机械领域, 尤其涉及车辆发动机的气门驱动领域, 特别是 一种压缩释放型发动机制动方法和装置。
背景技术
发动机制动可以分为压缩释放型制动和泄气型制动。 发动机的压缩释 放型制动在发动机活塞压缩冲程的后期打开排气门,在膨胀冲程的前期 (一 般在排气门正常开启之前) 关闭排气门。 压缩释放型制动器的一个先例由 康明斯 (Cummins)于 1965年在美国专利号 3220392披露。 制动系统经过液 压回路将机械输入传递到要打开的排气门。 液压回路上通常包括在主活塞 孔内往复运动的主活塞, 该往复运动来自于发动机的机械输入, 比如说发 动机喷油凸轮的运动或相邻排气凸轮的运动。 主活塞的运动通过液压流体 传递到液压回路上的副活塞, 使其在副活塞孔内往复运动, 副活塞直接或 间接地作用在排气门上, 产生发动机制动运作的气门运动。
发动机的泄气型制动是排气门除了正常的开启之外, 还 ί部分周期内 保持小量恒开 (部分周期泄气制动), 或在非排气冲程的周期内 (进气冲程, 压缩冲程, 和膨胀冲程)保持小量恒开 (全周期泄气制动)。 部分周期泄气制 动和全周期泄气制动的主要区别, 在于前者在大部分的进气冲程中不打开 排气门。 本发明人在美国专利号 6594996为泄气型发动机制动体系和方法 提供了相关的说明和实例。
发动机的压缩释放型制动和泄气型制动的区别主要有两点。 第一个主 要区别是制动排气门的开启相位 (制动时间) 不同。 全周期泄气型制动的 制动排气门是始终打开的, 因此不牵涉到开启时间。 部分周期泄气型制动 的制动排气门的开启时间是在发动机的进气冲程的后期; 而压缩释放型制 动的制动排气门的开启时间是在发动机的压缩冲程的后期, 比部分周期泄 气型制动的制动排气门的开启时间要晚很多,因此开启的载荷也要大得多。 第二个主要区别是制动排气门的开启高度 (制动阀升) 不同。 泄气型制动 的制动排气门的制动阀升大致为 0.5〜1.0mm (—般小于 l .Omm) , 而压縮释 放型制动的制动排气门的制动阀升大致为 2.0~3.5mm (液压式制动器的制 动阀升一般大于 2.0imn)。 上述区别导致设计要求和制动性能的不同。 压 縮释放型的制动功率大于泄气型制动, 但泄气型制动的制动开启载荷远小 于压縮释放型制动。 泄气型制动器必须与排气制动器 (如排气蝶阀) 联合 使用, 而压缩释放型制动器可以单独使用 (不需要排气制动器)。
发动机全周期泄气制动系统的一个先例由缪尔 (Muir)于 1970年在美国 专利第 3525317号公开。 该制动系统将发动机制动分为三档。 第一档是发 动机和车辆各运动部件造成的摩擦损失而产生的制动。 第二档是将发动机 的排气门保持连续小量恒开而产生的全周期泄气制动。 第三档是在第二档 的全周期泄气制动的基础上增加排气蝶阀, 产生联合制动。
德国曼 (MAN)的库比什 (Kubis) 等于 1992年在美国专利第 5086738 号公开了发动机部分周期泄气制动系统。 发动机制动时排气门在发动机进 气冲程快结束时小量打开, 然后在整个压縮冲程内保持小量恒开, 最后在 发动机的膨胀冲程的前期关闭。
前面说过, 发动机泄气型制动器单独使用效果不好, 制动功率远低于 压缩释放型制动器。因此,发动机泄气型制动器都与发动机排气制动器(如 排气蝶阀) 联合使用, 形成联合制动。 使用排气蝶阀或其它排气限流装置 使排气背压升高有可能导致排气门反跳或浮动(浮阔)。发动机行业一般对 浮阀不赞成, 因为浮阀时排气门的开启和关闭不是由凸轮驱动的, 气门的 落座速度无法控制。 太大的气门落座速度有可能损坏发动机。 然而, 加拿 大的 PacBmke于 1989年在美国专利第 4848289号公开了使用排气制动器 提高排气背压导致浮阀的制动方法。
瑞典的沃尔沃 (Volvo) 于 1992年在美国专利第 5146890号公开了一 种压縮释放型发动机制动器与排气制动器一起使用的联合制动方法。 其中 发动机的制动凸轮除了压缩释放制动凸台外, 增加了排气再循环 (EGR) 凸台。排气门在进气冲程的后期打开,由排气制动器产生的高背压尾气(制 动时为空气), 从排气管内反充发动机汽缸, 增加压縮制动功率。
德国曼 (MAN) 的拉默(Rammer)等于 1997年在美国专利第 5692469 号公开了一种利用排气制动器提高排气背压导致浮阀 (气门反跳) 进而开 启泄气型制动器的装置和方法。 当排气背压足够高时, 排气门在进气冲程 临近结束时浮开或反跳。 在该排气门浮动期间, 用一制动装置对其进行干 预,也就是在浮开的排气门关闭之前,通过一个油压控制的活塞将其截住, 阻止它关闭, 让它保持小量恒开, 产生部分周期泄气制动 (排气门在排气 冲程后关闭)。 该制动系统是用于每缸单排气门的发动机。 2006年, 拉默
(Rammer) 等将上述技术扩展到每缸双排气门的发动机 (美国专利第 7013867号, 中国专利第 200310123153.7号)。
德国曼 (MAN)的上述泄气型发动机制动系统的可靠性和耐久性面临着 很多问题, 因为它依赖于制动排气门的间歇开放或浮动, 这无论在时间和 大小上都是不一致的。 众所周知, 排气门的浮动高度依赖于排气背压, 而 排气背压依赖于发动机的转速, 并受排气制动器的质量与控制以及排气系 统设计的影响。 在发动机的中、 低转速速时, 排气门的浮动可能不够或根 本没有, 发动机制动装置无法启动。 而此时发动机制动的需求很高, 因为 商用车发动机大部分时间运行在中、 低转速。 此外, 过高的排气背压不仅 浮动被制动的排气门, 同时也浮动不制动的排气门。 不制动的排气门的落 座速度将太大, 影响发动机的可靠性和耐久性。
本发明人于 2010年在美国专利第 7673600号 (中国专利申请公幵号 CN1991136A) 公开了一种利用凸轮驱动而产生的部分周期泄气型制动装 置和方法。 发动机的阀桥内集成有主、 副活塞。 主活塞内有单向供油阀, 主活塞和副活塞之间的液压流道内还设置有另外一个制动单向阀。 制动凸 轮与发动机的常规排气凸轮集成, 包括泄气型制动凸台。 泄气型制动凸台 在发动机进气冲程的后期开始从凸轮的内基圆往上升。 在进气冲程的下止 点附近上升到最高升程, 然后在发动机的压縮冲程和膨胀冲程期间保持该 最高升程不变, 最后平滑地过渡进入常规排气凸台。 发动机制动时, 不是 靠排气背压升高浮动排气门而幵启制动, 而是由制动凸台推动阀桥内的主 活塞, 主活塞驱动副活塞打开排气门, 副活塞由制动单向阀锁定在伸出位 置, 将排气门保持小量恒开, 产生部分周期泄气型制动。
上述的许多制动装置的制动驱动机构都是集成在发动机的阀桥内的。 阀桥制动装置的一个先例是由卡尔维 (Calvin) 于 1970年在美国专利号 3,520,287披露。 整个阀桥套在一根中央导杆上。 导杆内部有制动油道和控 制阀。 导杆上部作为一个制动活塞, 阀桥通过其内部的活塞孔沿制动活塞 滑动。
一个改进了的阀桥制动机构由斯可乐(Sickler)于 1986年在美国专利 号 4,572,114披露。 一个专用的制动活塞安置在阀桥中央向上开的活塞孔 内, 使制动活塞与阔桥之间的相对运动大大减小。 该阀桥制动机构用于四 冲程发动机, 但是每个循环周期内产生两次压缩释放制动。
美国皆可博公司 (JVS ) 为南韩现代 (Hyundai) 卡车公司设计和制造 的阀桥制动装置(参见美国专利公开号 US 20050211206, 本发明人为该专 利申请的发明人之一) 在斯可乐 (Sickler) 的阀桥制动机构的基础上增加 了一种阀升重置机构。 此外, 阔桥内可以设置一到三个活塞, 制动时打开 一个或两个排气门。
黄(Huang)和本发明人以及舒沃尔(Schwoerer)于 2007年在美国专 利第 7284533号 (中国专利申请公开号 CN101490393A) 公开了一种利用 制动凸轮型线来实现制动设计要求和优化制动功能的方法。
发明内容:
本发明的目的在于提供一种压缩释放型发动机制动方法, 所述的这种 压縮释放型发动机制动方法要解决现有技术中发动机制动机构存在的可靠 性和耐久性不好、 安装和调试不方便以及增加发动机高度和重量的技术问 题。
本发明的这种压缩释放型发动机制动方法包括一个利用发动机的排气 门驱动链开启排气门的过程,所述的排气门驱动链包括凸轮、摇臂和阀桥, 所述的发动机的排气门中包括有一个第一排气门和一个第二排气门, 所述 的凸轮中含有至少一个制动凸台, 所述的制动凸台包括一个从凸轮的内基 圆上升到最大升程的上升段和一个保持所述的最大升程的等高段, 所述的 摇臂中设置有一个供油通道, 其中, 在所述的阀桥的中央向上开口设置一 个主活塞孔, 在阀桥的一端向下开口设置一个副活塞孔, 在所述的主活塞 孔和副活塞孔之间连接设置一条液压通道, 在主活塞孔内滑动式地设置一 个主活塞, 主活塞相对于主活塞孔具有一个伸出位置和一个缩回位置, 在 副活塞孔内滑动式地设置一个副活塞,将主活塞的上端与所述的摇臂连接, 在主活塞内设置一个油路, 将所述的油路的上端与所述的摇臂中的供油通 道相通, 将油路的下端与主活塞孔相通, 在主活塞孔与供油通道之间、 或 者在供油通道之内设置一个单向供油阀, 所述的单向供油阀的供油方向是 从供油通道向主活塞孔, 将副活塞的下端与所述的第一排气门相连, 将阀 桥另一端的下侧与所述的第二排气门相连, 在副活塞孔所在的阀桥一端的 上侧设置一个制动支架, 在所述的利用发动机的排气门驱动链开启排气门 的过程中, 首先, 通过所述的供油通道和单向供油阀向主活塞孔供油, 将 主活塞置于伸出位置, 打开主活塞孔和副活塞孔之间的液压通道, 然后, 利用凸轮中制动凸台的上升段驱动所述的摇臂, 使摇臂推动主活塞从伸出 位置移向缩回位置, 同时利用所述的制动支架阻止阀桥上移, 利用所述的 液压通道中的液压将主活塞的运动传递给副活塞, 迫使所述的副活塞在副 活塞孔内向下伸出, 打开第一排气门, 之后, 利用凸轮中制动凸台的等高 段驱动摇臂, 将主活塞在主活塞孔内保持在缩回位置上, 阻断主活塞孔通 过所述的液压通道与副活塞孔之间的液压传递, 将副活塞保持在副活塞孔 内的伸出位置, 保持第一排气门的打开状态, 同时利用制动支架承载副活 塞上的制动载荷。
进一步的, 在副活塞孔所在的阀桥一端内设置至少一个卸油通道, 将 所述的卸油通道的下端与副活塞孔相通, 利用所述的制动支架的下端封闭 卸油通道的上端开口。
进一步的, 在所述的制动凸台上设置一个下降段, 将所述的下降段的 起点连接在所述的等高段的末端, 将下降段的终点回到或靠近凸轮的内基 圆。
进一步的, 在凸轮中制动凸台经过等高段后、 进入下降段的过程中, 利用摇臂做反向运动, 使主活塞从缩回位置移向伸出位置, 打开液压通道 在主活塞孔上的开口, 接通主活塞孔与副活塞孔之间的液压传递, 使副活 塞在第一排气门的作用力下向缩回位置移动。
进一步的, 将主活塞内的油路沿主活塞的轴向设置, 将油路的下端开 口设置在主活塞的下端端面内。
或者, 在所述的凸轮上设置集成式排气凸台, 在所述的制动凸台上设 置一个缓升段, 将所述的缓升段的起点连接在所述的等高段的末端, 将缓 升段的终点汇入所述的集成式排气凸台,在凸轮中制动凸台经过等高段后、 进入缓升段的过程中, 利用制动凸台的缓升段驱动所述的摇臂, 使摇臂通 过位于主活塞孔内缩回位置上的主活塞往下推动阀桥, 使副活塞孔所在的 阀桥一端与位于其上侧的所述的制动支架分离, 打开卸油通道的上端幵口 卸油, 减少副活塞孔内的液压, 使副活塞在第一排气门的作用力下在副活 塞孔内向上移往缩回位置, 使第一排气门向上移往关闭位置。
进一步的, 所述的利用发动机的排气门驱动链开启排气门的过程包括 以下步骤:
1) 打开发动机的制动控制机构,通过所述的供油通道和单向供油阀向 阀桥内的主活塞孔供油,
2) 主活塞在主活塞孔内置于伸出位置,开通阀桥内的主活塞孔和副活 塞孔之间的液压通道,
3) 副活塞在副活塞孔内置于缩回位置,副活塞下面的第一排气门处于 关闭位置,
4) 凸轮的制动凸台从内基圆向上移动,驱动主活塞孔内的主活塞向下 往阀桥的主活塞孔内的缩回位置运动,
5) 位于副活塞孔上方的阀桥上面的制动支架阻止或限制阔桥向上运 动,
6) 主活塞的向下运动通过液压通道传递给副活塞,阀桥的副活塞孔内 的副活塞向下往伸出位置运动, 打开第一排气门,
7) 凸轮的制动凸台抵达最高升程并继续保持所述的最高升程位置,
8) 主活塞在阀桥的主活塞孔内向下抵达缩回位置,关闭主活塞孔和副 活塞孔之间的液压通道, 阻止副活塞上的液压载荷传递到主活塞,
,9) 副活塞在阀桥的副活塞孔内向下抵达伸出位置,将副活塞下面的第 一排气门保持打开在最高制动阀升位置,
10)利用副活塞孔所在的阀桥一端上侧的制动支架来支撑第一排气门 传给副活塞的载荷,
11)凸轮的制动凸台从最高升程下降回到内基圆,
12)主活塞从阀桥的主活塞孔内的缩回位置往上移回到伸出位置,打开 主活塞孔和副活塞孔之间的液压通道,
13)副活塞从副活塞孔内的伸出位置往上移回到缩回位置,
14)第一排气门从最高制动阀升位置往上移向关闭位置。
进一步的, 所述的利用发动机的排气门驱动链开启排气门的过程还包 括以下步骤:
1) 关闭发动机的制动控制机构, 停止向阀桥内的主活塞孔供油, 2) 凸轮驱动阀桥的主活塞孔内的主活塞向下运动,
3) 主活塞驱动阀桥向下运动,副活塞孔所在的阀桥一端与其上侧的制 动支架分离,
4) 打开副活塞孔上方的卸油通道卸油,
5) 副活塞从阀桥的副活塞孔内移到缩回位置。
进一步的, 在主活塞于主活塞孔内从缩回位置滑向伸出位置时, 利用 主活塞打开液压通道位于主活塞孔上的开口, 在主活塞于主活塞孔内从伸 出位置滑向缩回位置时,利用主活塞关闭液压通道位于主活塞孔上的开口。
进一步的, 所述的卸油通道设置有一个出口, 在阀桥由凸轮驱动向下 移动时, 阀桥与制动支架分离, 打开所述的卸油通道的出口。
进一步的, 将所述的制动支架固定在发动机上, 所述的制动支架包括 连接件, 所述的连接件位于阀桥的上方。
进一步的, 将所述的制动支架集成在所述的摇臂上, 所述的制动支架 包括连 Ϊ妾件, 所述的连接件位于阀桥的上方。
进一步的, 所述的制动凸台中包括有一个压缩释放凸台, 所述的压縮 释放凸台在发动机的压缩冲程的后期从凸轮的内基圆开始上升, 并在发动 机的压缩上止点附近达到最高位置, 在发动机的膨胀冲程的前期下降回到 凸轮的内基圆。
进一步的, 所述的制动凸台中包括有一个压縮释放凸台和一个排气再 循环凸台, 所述的压缩释放凸台在发动机的压縮冲程的后期从凸轮的内基 圆开始上升, 并在发动机的压縮上止点附近达到最高位置, 在发动机的膨 胀冲程的前期下降回到凸'轮的内基圆, 所述的排气再循环凸台在发动机的 进气冲程的后期从凸轮的内基圆开始上升, 在发动机的压縮冲程的前期下 降回到凸轮的内基圆。
进一步的, 在所述的凸轮上设置一个集成式排气凸台, 所述的制动凸 台中包括有一个压缩释放凸台, 所述的压缩释放凸台在发动机的压缩冲程 的后期从凸轮的内基圆开始上升, 并在发动机的压缩冲程上止点之前上升 到最高位置, 在发动机的压缩冲程的剩余期间和发动机的膨胀冲程的初期 保持所述的最高位置, 在发动机的膨胀冲程的剩余期间下降回到凸轮的内 基圆或汇入集成式排气凸台, 所述的集成式排气凸台由底部和顶部组成, 集成式排气凸台的底部与制动凸台接近同高, 集成式排气凸台的顶部与发 动机的常规凸台接近相同。
进一步的, 所述的制动凸台中包括有一个排气再循环凸台, 所述的排 气再循环凸台在发动机的进气冲程的后期从凸轮的内基圆开始上升, 在发 动机的压缩冲程的前期下降回到凸轮的内基圆。
进一步的, 在所述的凸轮上设置一个集成式排气凸台, 所述的制动凸 台中包括有一个压缩释放凸台, 所述的压缩释放凸台在发动机的压縮冲程 的后半期从凸轮的内基圆开始上升, 并在发动机的压缩上止点之前上升到 最高位置, 在发动机的压縮冲程的剩余期间和发动机的膨胀冲程的前期保 持所述的最高位置, 在发动机的膨胀冲程的剩余期间上升汇入集成式排气 凸台。
进一步的, 利用一个预紧弹簧在排气门驱动链内部保持由主活塞的缩 回位置与伸出位置生成的排气门驱动链制动间隙, 利用所述的排气门驱动 链制动间隙消除排气门驱动链内部的不跟随和冲击。
本发明还提供了一种压縮释放型发动机制动装置, 所述的这种压縮释 放型发动机制动装置包括制动控制机构和制动驱动机构, 其中, 所述的制 动控制机构包括一个与液压产生装置相连接的控制阀, 制动驱动机构包括 制动箱体、 供油机构、 卸油机构和制动凸轮, 所述的制动箱体内设置有主 活塞孔和副活塞孔, 所述的主活塞孔和副活塞孔之间设置有一条连通的液 压通道, 主活塞孔内滑动式地设置有主活塞, 副活塞孔内滑动式地设置有 副活塞, 所述的供油机构包括供油通道和单向供油阀, 所述的制动控制机 构中的控制阀与所述的供油通道的入口连接, 供油通道的出口与主活塞孔 连接, 所述的单向供油阀设置在供油通道或者供油通道与主活塞孔之间, 单向供油阀的供油方向是从供油通道进入主活塞孔, 所述的卸油机构包括 一个卸油阀, 所述的卸油阀与副活塞孔连通, 所述的制动凸轮中含有至少 一个制动凸台。
进一步的, 所述的制动箱体由阀桥构成, 所述的主活塞孔设置在所述 的阀桥中央的一个向上开口内, 所述的副活塞孔设置在阀桥的一端的一个 向下开口内, 所述的液压通道设置在阀桥内并连通主活塞孔和副活塞孔, 所述的主活塞设置在主活塞孔内, 所述的副活塞设置在副活塞孔内, 主活 塞的上端与发动机的摇臂固定连接, 所述的摇臂中设置有一个供油通道, 主活塞内设置有一个油路, 所述的油路的上端与所述的摇臂中的供油通道 相通, 油路的下端与主活塞孔相通, 所述的单向供油阀设置在主活塞孔与 供油通道之间或者供油通道之内, 所述的单向供油阀的供油方向是从供油 通道向主活塞孔, 副活塞孔所在的阀桥一端的上侧设置有一个制动支架, 副活塞孔所在的阀桥一端设置有至少一个卸油通道, 所述的卸油通道的一 端与副活塞孔相通, 卸油通道的另一端由制动支架的下端封闭, 所述的制 动凸轮上设置有集成式排气凸台。
进一步的, 副活塞的下端与发动机排气门中的一个第一排气门相连, 阀桥另一端的下侧与发动机排气门中的一个第二排气门相连。
进一步的, 所述的制动支架固定在发动机上, 所述的制动支架包括连 接件, 所述的连接件位于阀桥的上方。
进一步的, 所述的制动支架集成在摇臂上, 所述的制动支架包括连接 件, 所述的连接件位于阀桥的上方。
进一步的, 所述的制动支架的连接件包括过渡活塞, 所述的过渡活塞 滑动式地安置在阔桥的过渡活塞孔内, 所述的过渡活塞孔位于所述的副活 塞孔之上。
进一步的, 所述的制动凸台中包括有一个压缩释放凸台, 所述的压缩 释放凸台在发动机的压缩冲程的后期从凸轮的内基圆开始上升, 并在发动 机的压缩上止点附近达到最高位置, 在发动机的膨胀冲程的前期下降回到 或靠近凸轮的内基圆。
进一步的, 所述的制动凸台中包括有一个压縮释放凸台和一个排气再 循环凸台, 所述的压縮释放凸台在发动机的压缩冲程的后期从凸轮的内基 圆开始上升, 并在发动机的压缩上止点附近达到最高位置, 在发动机的膨 胀冲程的前期下降回到或靠近凸轮的内基圆, 所述的排气再循环凸台在发 动机的进气冲程的后期从凸轮的内基圆开始上升, 在发动机的压缩冲程的 前期下降回到凸轮的内基圆。 ' 进一步的, 在所述的凸轮上设置有一个集成式排气凸台, 所述的制动 凸台中包括有一个压缩释放凸台, 所述的压缩释放凸台在发动机的压缩冲 程的后期从凸轮的内基圆开始上升, 并在发动机的压縮冲程上止点之前上 升到最高位置, 在发动机的压缩冲程的剩余期间和发动机的膨胀冲程的初 期保持所述的最高位置, 在发动机的膨胀冲程的剩余期间下降回到凸轮的 内基圆或汇入集成式排气凸台,所述的集成式排气凸台由底部和顶部组成, 集成式排气凸台的底部与制动凸台接近同高, 集成式排气凸台的顶部与发 动机的常规凸台接近相同。
进一步的, 所述的制动凸台中包括有一个排气再循环凸台, 所述的排 气再循环凸台在发动机的进气冲程的后期从凸轮的内基圆开始上升, 在发 动机的压缩冲程的前期下降回到凸轮的内基圆。
进一步的, 在所述的凸轮上设置有一个集成式排气凸台, 所述的制动 凸台中包括有一个压縮释放凸台, 所述的压缩释放凸台在发动机的压缩冲 程的后半期从凸轮的内基圆开始上升, 并在发动机的压缩上止点之前上升 到最高位置, 在发动机的压缩冲程的剩余期间和发动机的膨胀冲程的前期 保持所述的最高位置, 在发动机的膨胀冲程的剩余期间上升汇入集成式排 气凸台。 进一步的, 所述的制动驱动机构中设置有一个预紧弹簧。
进一步的, 所述的预紧弹簧的一端安置在所述的发动机上, 预紧弹簧 的一端作用在所述的摇臂的一端上。
再进一步的, 所述的制动驱动机构中设置有一个自动间隙补偿机构。 本发明的工作原理是: 当需要发动机制动时, 制动控制机构打开, 向 制动驱动机构供油。 低压机油 (发动机润滑油) 从供油通道和单向供油阀 进入主活塞孔内, 主活塞在阀桥的主活塞孔内处于伸出位置, 打开主活塞 孔和副活塞孔之间的液压通道。 凸轮的制动凸台从内基圆往上升, 摇臂驱 动阀桥内的主活塞从伸出位置往下移向主活塞孔底面的缩回位置, 主活塞 的向下运动通过液压通道传递给副活塞。 位于副活塞孔上方阀桥上面的制 动支架, 阻止阀桥因副活塞孔内的油压而上升。 阀桥的副活塞孔内的副活 塞向下伸出, 打开位于副活塞下面的制动排气门。 凸轮进入制动凸台的最 高升程, 主活塞在阀桥的主活塞孔内向下抵达孔底的缩回位置, 堵住液压 通道的入口, 关闭主活塞孔和副活塞孔之间的液压通道。 副活塞在阀桥的 副活塞孔内向下抵达伸出位置, 将副活塞下面的排气门保持打开一间隙。 副活塞上的制动载荷无法通过液压通道传递给主活塞, 只能通过阀桥传递 给位于副活塞孔上方阀桥上面的制动支架。 此时, 主活塞和排气门致动器 (包括摇臂和凸轮等) 都不承受制动载荷。 凸轮从制动凸台的最高升程下 降时, 主活塞从阀桥的主活塞孔内的缩回位置往上移向伸出位置, 打开主 活塞孔和副活塞孔之间的液压通道, 副活塞孔内的副活塞随着主活塞一起 向上移动。 主活塞在阀桥的主活塞孔内向上回到伸出位置, 副活塞在阀桥 的副活塞孔内向上回到缩回位置,副活塞下面的排气门往上移向关闭位置。
凸轮的集成式排气凸台从内基圆往上升, 摇臂驱动阀桥内的主活塞从 伸出位置往下移向主活塞孔底面的缩回位置, 主活塞的向下运动通过液压 通道传递给副活塞。 位于副活塞孔上方阀桥上面的制动支架, 阻止阀桥因 副活塞孔内的油压而上升。 阀桥的副活塞孔内的副活塞向下伸出, 打开位 于副活塞下面的制动排气门。 凸轮进入集成式排气凸台的顶部, 主活塞压 迫主活塞孔底, 驱动阀桥向下运动。 阀桥与位于其上面的制动支架分离, 打开阀桥内副活塞孔上方的卸油通道卸油, 副活塞从阀桥的副活塞孔内从 伸出位置移到缩回位置。 阀桥将集成式排气凸台顶部的运动传递给两个排 气门, 产生常规排气门运动。 .
本发明和已有技术相比, 其效果是积极和明显的。 本发明将压缩释放 型制动机构集成在发动机现有的气门驱动链内部, 并利用制动支架承担制 动载荷和重置制动阀升, 设计简单, 结构紧凑, 减小了发动机的制动载荷, 增加了发动机的制动功率, 改进了发动机运作的可靠性和耐久性。
附图说明
图 1是本发明中的压缩释放型发动机制动装置的第一个实施例在制动 时凸轮处于内基圆位置的示意图。
图 2是本发明中的压缩释放型发动机制动装置的第一个实施例在制动 时凸轮处于制动凸台的最高位置的示意图。
图 .3是本发明中的压缩释放型发动机制动装置的制动控制机构处于 "开"位置的示意图。
图 4是本发明中的压缩释放型发动机制动装置的制动控制机构处于 "关"位置的示意图。
图 5是本发明中的压缩释放型发动机制动装置的一种凸轮型线的示意 图。
图 6是本发明中的压缩释放型发动机制动装置的一种排气门升程曲线 和进气门升程曲线的示意图。
图 7是本发明中的压缩释放型发动机制动装置的又一种凸轮型线的示 意图。
图 8是本发明中的压缩释放型发动机制动装置的又一种凸轮型线的示 意图。 图 9是本发明中的压縮释放型发动机制动装置的第二个实施例在非制 动时凸轮处于内基圆位置的示意图。
图 10是本发明中的压缩释放型发动机制动装置的第二个实施例在制动 时凸轮处于内基圆位置的示意图。
具体实施方式
实施例 1:
如图 1和图 2所示, 本发明的压缩释放型发动机制动装置的第一个实 施例在制动时凸轮 230分别处于内基圆 225位置和制动凸台最高升程位置。 图 1和图 2中包括三个主要组成部分: 排气门致动器 200、排气门 300 (包 括第一排气门 3001和第二排气门 3002 ) 和发动机制动驱动机构 100。
排气门致动器 200包括凸轮 230、凸轮从动轮 235、摇臂 210以及阀桥 400。排气门致动器 200和排气门 300合在一起可称为排气门驱动链。通常 在摇臂 210的一端 (靠近阀桥 400的一侧或者靠近凸轮 230的一侧) 带有 阀隙调节系统。 本实施例中的阀隙调节系统由设置在阀桥 400—侧的阀隙 调节螺钉 110构成, 阀隙调节螺钉 110位于摇臂 210上并由锁紧螺帽 105 固定。 阀隙调节螺钉 110与象足垫 114相连。 摇臂 210摆动式地安装在摇 臂轴 205上。
第一排气门 3001和第二排气门 3002分别由气门弹簧 3101和气门弹簧 3102 (简称气门弹簧 310 ) 顶置在发动机缸体 500内的阀座 320上, 阻止 气体 (发动机制动时为空气) 在发动机汽缸和排气管 600之间的流动。 排 气门致动器 200将凸轮 230的机械运动, 通过阀桥 400传递给第一排气门 3001和第二排气门 3002, 使其周期性地打开和关闭。
制动驱动机构 100包括制动箱体、 制动支架和制动凸轮。 本实施例中 的制动箱体采用发动机的阀桥 400。 阀桥 400的中央向上开口设置有一个 主活塞孔 415, 阀桥 400的一端向下开口设置有一个副活塞孔 190。主活塞 孔 415和副活塞孔 190由一条液压通道 412相连。 主活塞孔 415还通过单 向供油阀 172与其上方的供油通道 115相连。 主活塞孔 415内和副活塞孔 190内分别滑动式地设置有主活塞 162和副活塞 (又叫制动活塞) 160。 主 活塞 162的上面受来自摇臂 210的作用。 副活塞 160的下面与发动机的可 作制动用的第一排气门 3001相连。阀桥 400的另一端的下面与发动机的非 制动作用的第二排气门 3002相连。副活塞孔 190上方的阀桥 400内设置有 卸油通道 197, 卸油通道 197和副活塞孔 190相通, 卸油通道 197的上方 设置有一个制动支架 125。 制动支架 125包括可调的连接件 1052与 1142 和紧固件 1102。 制动支架 125可以固定在发动机上。 制动支架 125 (通过 连接件)位于副活塞孔 190上方的阀桥 400上并封闭卸油通道 197的出口。 制动凸轮与发动机的常规凸轮集成, 所集成的凸轮 230上含有至少一个制 动凸台和集成式排气凸台 220。 这里的凸轮 230的制动凸台包括在内基圆 225上的压縮释放凸台 233和排气再循环凸台 232。
排气摇臂 210和发动机之间可以设置一根预紧弹簧 198。本实施例中, 预紧弹簧 198为片弹簧, 其一端安置在制动支架 125上, 另一端安置在摇 臂 210上。 预紧弹簧 198可以是螺旋弹簧和其它形式的弹簧。
预紧弹簧 198也可以使用不同的安装方式, 设置在不同的地方, 比如 在主活塞 162与阀桥 400之间、 凸轮 230 (或推杆式发动机的推杆) 与摇 臂 210之间等。 预紧弹簧 198保持由主活塞 162的縮回位置 (图 2 ) 与伸 出位置(图 1 )在排气门驱动链内部生成的制动间隙 234 (此间隙在非制动 时可以在凸轮 230的内基圆 225和凸轮从动轮 235之间),消除排气门驱动 链内部的不跟随和冲击。
在阀桥 400内设置定位销 137,在副活塞 160上设置限位槽 142, 形成 活塞限位机构, 限制副活塞 160的最大冲程。 副活塞 160和阀桥 400之间 可以设置一根弹簧 177。
本实施例中, 在阀桥 400内还设置了一个泄压机构。 所述的泄压机构 包括副活塞 160上的泄压孔 152。 当副活塞孔 190内的油压增高时, 通过 副活塞 160和孔 190之间的间隙以及制动活塞 160上的定位槽 137和泄压 孔 152的机油泄漏随之增大, 使得作用在副活塞 160上的油压不超过所设 计的预定值。
当需要发动机制动时, 如图 3所示, 打开制动控制机构 50。 通过制动 流体网路, 向制动驱动机构 100供油。制动流体网路包括众多的供油通道, 如摇臂轴 205内的轴向孔 211和径向孔 212、 摇臂 210内的切口 213和油 孔 214和阀隙调节螺钉内的横孔 113和竖孔 115 (与象足垫 114内的孔相 通)。 低压机油从供油通道, 通过设置在主活塞 162上的单向供油阀 172, 向主活塞孔 415内供油。 主活塞 162在闽桥 400的主活塞孔 415内处于如 图 1所示的伸出位置, 主活塞 162与主活塞孔 415的孔底面 446 (也就是 阀桥 400 )之间形成一制动间隙 234,主活塞孔 415和副活塞孔 190之间的 液压通道 412处于打开位置。
为简明起见, 发动机的润滑油道在此没有显示。 当然, 润滑油道也可 以和制动油道合二为一, 采用两级不同的油压供油。 润滑时采用低油压, 比如说, 一个巴或更低; 制动时采用高油压, 比如说, 两个巴或更高。
当凸轮 230的制动凸台 (压缩释放凸台) 233从内基圆 225往上升时, 摇臂 210驱动阀桥 400内的主活塞 162从图 1的伸出位置往下移向主活塞 孔底面 446的縮回位置, 通过主活塞孔 415和副活塞孔 190之间的液压通 道 412, 将主活塞 162的向下运动传递给副活塞 160。 位于副活塞孔 190 上方的阀桥 400上的制动支架 125, 使阀桥 400不会因为副活塞孔 190内 的油压而上升。 阀桥 400的副活塞孔 190内的副活塞 160只能向下伸出, 打开位于副活塞 160下面的制动第一排气门 3001。在凸轮 230进入制动凸 台 233的最高升程时, 主活塞 162在阀桥 400的主活塞孔 415内向下抵达 孔底 446的缩回位置 (图 2), 堵住液压通道 412的入口 472, 关闭主活塞 孔 415和副活塞孔 190之间的液压通道 412。 与此同时, 副活塞 160在阀 桥 400的副活塞孔 190内向下抵达伸出位置, 副活塞 160的冲程为 130, 副活塞 160下面的第一排气门 3001相应地打开一间隙 330。 此时, 副活塞 160上的制动载荷无法通过液压通道 412传递给主活塞 162,只能通过阀桥 400传递给位于副活塞孔 190上方的阀桥 400上的制动支架 125。 主活塞 162和排气门致动器 200 (包括摇臂 210和凸轮 230 ) 都不承受制动载荷。 在凸轮 230从制动凸台 233的最高升程下降时, 主活塞 162从阀桥 400的 主活塞孔 415内的縮回位置往上移向伸出位置, 打开主活塞孔 415和副活 塞孔 190之间的液压通道 412, 副活塞孔 190内的副活塞 160随着主活塞 162—起向上移动。 当主活塞 162在阀桥 400的主活塞孔 415内向上回到 伸出位置时, 副活塞 160在阔桥 400的副活塞孔 190内向上回到缩回位置 (图 1 )。
当凸轮 230的集成式排气凸台 220从内基圆 225往上升时, 摇臂 210 驱动阀桥 400内的主活塞 162从图 1的伸出位置往下移向主活塞孔底面 446 的縮回位置, 通过主活塞孔 415和副活塞孔 190之间的液压通道 412, 将 主活塞 162的向下运动传递给副活塞 160。 位于副活塞孔 190上方的阀桥 400上的制动支架 125, 阀桥 400不会因为副活塞孔 190内的油压而上升。 阀桥 400的副活塞孔 190内的副活塞 160只能向下伸出, 打开位于副活塞 160下面的第一排气门 3001。 在凸轮 230进入集成式排气凸台 220的顶部 (大于制动凸台 233的最高升程) 时, 主活塞 162压迫主活塞孔底 446, 驱动阀桥 400向下运动。 阀桥 400与位于其上面的制动支架 125分离, 打 开阀桥 400内与副活塞孔 190相通的卸油通道 197卸油, 副活塞 160从阀 桥 400的副活塞孔 190内从伸出位置移到缩回位置。 阀桥 400将集成式排 气凸台 220顶部的运动传递给第一排气门 3001和第二排气门 3002, 产生 常规排气门运动。
如果凸轮 230的制动凸台还包括排气再循环凸台 232, 那么排气再循 环凸台 232通过排气门驱动链幵启第一排气门 3001的过程,与上述的压缩 释放凸台 233通过排气门驱动链开启第一排气门 3001的过程相同,在此不 再复述。 如果发动机有足够的排气背压, 那么增加排气再循环凸台 232之 后, 发动机的制动功率有可能进一步改善。
当不需要发动机制动时, 如图 4所示, 关闭制动控制机构 50, 停止向 制动驱动机构 100供油。 在凸轮 230迸入集成式排气凸台 220的顶部 (大 于压缩释放凸台 233的最高升程) 时, 主活塞 162压迫主活塞孔底 446, 驱动阀桥 400向下运动。 阀桥 400与位于其上面的制动支架 125分离, 打 开阀桥 400内与副活塞孔 190相通的卸油通道 197卸油, 副活塞 160从阔 桥 400的副活塞孔 190内从伸出位置 (图 2 ) 移到縮回位置 (图 1 )。 阀桥 400将集成式排气凸台 220顶部的运动传递给第一排气门 3001和第二排气 门 3002, 产生常规排气门运动。 在凸轮 230从集成式排气凸台 220的顶部 进入其底部回到内基圆的过程中, 副活塞 160保持在图 1所示的缩回位置 (由于排气门弹簧 3101的向上作用力), 主活塞 162保持在图 2所示的缩 回位置(由于预紧弹簧 198的向下作用力), 摇臂 210上的凸轮从动轮 235 与凸轮 230的内基圆 225之间形成一间隙。 由于该间隙, 制动凸台 (压缩 释放凸台 233和排气再循环凸台 232 )的运动将不会传递给排气门 300,只 有集成式排气凸台 220顶部的运动传递给排气门 300, 产生常规排气门运 动, 发动机的制动运作被解除。
如图 3和图 4所示, 本发明的压缩释放型发动机制动装置的制动控制 机构 50处于 "开"和 "关"的位置。 图中的电磁阀 51为二位三通型。 当 制动控制机构 50打开时 (图 3 ), 电磁阔 51的阀体向下打开供油口 111, 同时关闭卸油口 222, 发动机的低压机油 (润滑油) 从制动流体通道流向 制动驱动机构 100 (图 1和图 2 )。 当制动控制机构 50关闭时 (图 4), 电 磁阀 51的阀体向上关闭供油口 111, 同时打开卸油口 222, 发动机的低压 机油 (润滑油) 停止流向制动驱动机构 100 (图 1和图 2), 制动驱动机构 100反而从制动流体通道和卸油口 222卸油。 由于阀桥 400内的副活塞孔 190上设置有一卸油通道 197 (图 1和图 2 ), 完全有可能使用二位双通电 磁阀, 也就是说, 不需要卸油口 222。
图 5表示了本发明的压縮释放型发动机制动装置中的一种凸轮型线, 其中包括制动凸台和集成式排气凸台 220,制动凸台包括压缩释放凸台 233 和排气再循环凸台 232。 压缩释放凸台 233包括三个部分: 上升段 "A" 、 等高段 "B "和下降段 " C"。 上升段 " A"从凸轮的内基圆 225上升到制 动的最高升程。 等高段 "B "在一段时间内将制动的最高升程基本保持不 变。下降段 " C "从制动的最高升程下降回到凸轮的内基圆 225。等高段 "B " 的作用是在制动时保持主活塞 162在闽桥 400的主活塞孔 415内处于孔底 446的缩回位置 (图 2), 关闭主活塞孔 415和副活塞孔 190之间的液压通 道 412,副活塞 160上的制动载荷无法通过液压通道 412传递给主活塞 162, 只能通过阀桥 400传递给位于其上的制动支架 125。这样排气门致动器 200 (包括摇臂 210和凸轮 230 ) 不承受制动载荷, 减少了排气门致动器 200 的受力和磨损, 增加了发动机的可靠性和耐久性。
排气再循环凸台 232也可以设计为压缩释放凸台 233的形状。 但由于 在排气再循环期间, 排气门的受力远小于压缩释放期间。 因此排气再循环 凸台 232的轮廓曲线形状的设计可以不考虑载荷的影响。
集成式排气凸台 220分为底部和顶部(图 5中的双点划线将它们分开)。 集成式排气凸台 220的底部为过渡部分, 与制动凸台接近同高; 集成式排 气凸台 220的顶部与发动机的常规凸台接近相同。 这样, 在非制动 (常规 点火) 运作时, 集成式排气凸台 220的底部连同制动凸台 (压縮释放凸台 233和排气再循环凸台 232 )的运动都因为排气门驱动链内部的间隙 234(图 1 )而被跳过或丢失, 不会传递给排气门 300 ; 只有集成式排气凸台 220的 顶部的运动被传递给排气门 300, 产生常规阀升运动。
图 6表示了本发明的压缩释放型发动机制动装置中的一种排气门的升 程曲线和进气门的升程曲线。发动机排气门的常规阔升曲线 220m的起点为 225a, 终点为 225b, 其最高升程大约为 220b。假设在阀桥 400内的副活塞 孔 190上没有卸油通道 197 (图 1和图 2 ), 那么发动机制动时由加大的常 规排气凸台 220产生的加大的主阀升曲线 220v的起点为 225h, 终点为 225c , 其最高升程 220e为 220a和 220b之和。 由于卸油通道 197, 制动排 气门 3001的阔升曲线在加大的主阀升曲线 220v的底部 220a与顶部 220b 之间的过渡点 220t向主阀升曲线 220m过渡,在 220s点与主阀升曲线 220m 融合, 在终点 225b比没有卸油通道时提前关闭。
在发动机制动运作时, 凸轮的制动凸台(排气再循环凸台 232和压缩释 放凸台 233 ) 的运动, 由摇臂 210传给主活塞 162 (图 1和图 2 ), 主活塞 162的运动通过液压通道 412传给副活塞 160和副活塞 160下面的排气门 3001, 产生排气再循环的制动阀升 232v和压縮释放的制动阀升 233v。 排 气再循环的制动阀升 232v的起点为 225d,位于发动机的进气冲程的后期, 也就是在进气门的阀升曲线 280v趋于关闭的时候;排气再循环的制动阀升 232v的终点为 225e,位于发动机的压缩冲程的前期。压缩释放的制动阀升 233v的起点为 225f, 位于发动机的压缩冲程的后期;压缩释放的制动阀升 233v的终点为 225g, 位于发动机的膨胀冲程的前期。 阀升曲线在 0〜720 ° 之间循环, 0° 和 720 ° 为同一点。
当凸轮 230的集成式排气凸台 220从内基圆 225往上升时(图 5 ), 摇 臂 210推动主活塞 162 (图 1和图 2), 主活塞 162推动副活塞 160, 副活 塞 160推动排气门 3001向下运动。 在凸轮 230进入集成式排气凸台 220 的顶部(大于制动凸台 233的最高升程) 时 (图 5 ), 主活塞 162开始驱动 阀桥 400向下运动 (图 2)。 阀桥 400与制动支架 125分离, 打开卸油通道 197卸油, 副活塞 160从伸出位置移到缩回位置, 制动排气门 3001的阀升 曲线从过渡点 220t向主阀升曲线 220m过渡 (图 6), 最后在终点 225b关 闭, 比没有卸流通道时的终点 225c大大超前。这样就减小了排气门在发动 机排气冲程的上止点位置的升程, 避免排气门与活塞的相撞, 也增加了制 动功率, 降低了汽缸内部的温度。 图 7表示了本发明的压縮释放型发动机制动装置的另一种凸轮型线。 这种凸轮型线与图 5所示的凸轮型线的区别在于压縮释放凸台 233。 压缩 释放凸台 233的前两部分也包括上升段 "A"和等高段 "B " , 但在等高段 "B "之后的下降段 "D"没有降到内基圆 225, 而是过渡汇入集成式排气 凸台 220。
图 8表示了本发明的压縮释放型发动机制动装置的又一种凸轮型线。 这种凸轮型线与图 5所示的凸轮型线的区别也在于压縮释放凸台 233。 压 缩释放凸台 233的前两部分同样包括上升段 "A"和等高段 "B " , 但在等 高段 "B "之后不下降, 而是通过一个缓升段 "E", 汇入集成式排气凸台 220ο 凸轮 230从制动凸台的等高段 "Β "进入缓升段 "Ε", 主活塞 160从 阀桥 400的主活塞孔底 446的缩回位置往下推动阀桥 400 (图 2),阀桥 400 与位于阀桥 400上的制动支架 125分离, 打开副活塞孔 190上方阀桥 400 内的卸油通道 197卸油, 副活塞 160在阀桥 400的副活塞孔 190内向上移 往縮回位置, 副活塞 160下面的排气门 3001跟着向上关闭。也就是说, 阀 桥 400内副活塞孔 190上的卸流通道 197将在缓升段 "Ε"被打开, 制动 排气门 3001的制动阀升有可能从最高阀升下降到零 (关闭)。 如图 9和图 10所示,本发明的压缩释放型发动机制动装置的第二个实 施例在非制动时和制动时凸轮处于内基圆的位置。 本实施例与第一个实施 例的区别在于本实施例采用了一种不同的制动支架 125。 位于阀桥 400上 面的制动支架 125的作用主要有两个: 一是在发动机制动时支撑住阀桥 400, 阻止或限制阀桥 400的向上运动,封闭副活塞孔 190上方的卸油通道 197, 承担从制动排气门 3001传过来的制动载荷; 二是在发动机制动的每 一个周期内, 在集成式排气凸台 220的顶部推动阀桥下移时, 打开副活塞 孔 190上方的卸油通道 197卸油,重置制动排气门 3001的阀升曲线。当然, 卸油机构也用于解除发动机的制动运作。 本实施例的制动支架 125还包括其它连接件, 如过渡活塞 161。 过渡 活塞 161滑动式地安置在阀桥 400上面的过渡活塞孔 191内, 形成一种自 动间隙补偿机构。卸油通道 197在副活塞孔 190的上方,将过渡活塞孔 191 和副活塞孔 190相连 (两个活塞孔的尺寸根据需要确定, 其大小不一定相 同) 。 过渡活塞 161内增加了一条卸油通道 196。 过渡活塞 161的移动范 围由压片 178控制。压片 178由螺钉 179固定在阀桥 400上。过渡活塞 161 的移动范围也可以通过其它方式, 如卡环等来控制。 过渡活塞 161的上面 与制动支架 125的另一连接件象足垫 1 142相连。 象足垫 1 142套在压球杆 1103的压球上。压球杆 1103也可以和调节螺钉 1102合在一起。象足垫 1142 与压球之间可以有一定的相对运动或间隙,弹簧 177将象足垫 1142向下偏 置在过渡活塞 161上, 封闭卸油通道 196和 197 (机油无法从过渡活塞孔 191和副活塞孔 190往外泄漏) 。
当不需要发动机制动时, 如图 4所示, 关闭制动控制机构 50, 停止向 制动驱动机构 100供油, 制动装置处于如图 9所示的非制动状态。 主活塞 孔 415和副活塞孔 190由于卸油机构而处于泄油状态。 主活塞 162在预紧 弹簧 198的作用下压靠在主活塞孔 415底面 446·的缩回位置, 在凸轮从动 轮 235与凸轮 230的内基圆 225之间形成一间隙 134。 副活塞 160压靠在 副活塞孔 190底面的縮回位置,副活塞 160下面的排气门 3001处于关闭位 置。 制动支架 125的过渡活塞 161在弹簧 177的作用下压靠在过渡活塞孔 191底面的缩回位置。 当凸轮 230从内基圆 225进入制动凸台 232或制动 凸台 233时, 由于排气门驱动链内部 (凸轮从动轮 235和凸轮 230之间) 的间隙 134, 制动凸台 232或制动凸台 233的运动被跳过或丢失, 不会传 递给排气门 300。 当凸轮 230进入集成式排气凸台 220的顶部时 (图 5, 7 和 8 ), 凸轮的运动通过摇臂 210、 主活塞 162、 阀桥 400和副活塞 160以 机械固链式的方式传递给排气门 300 (第一排气门 3001和第二排气门 3002 ), 产生常规排气门运动。 当需要发动机制动时, 如图 3所示, 打开制动控制机构 50, 向制动驱 动机构 100供油。制动装置从如图 9所示的非制动状态进入如图 10所示的 制动状态。低压机油从供油通道,通过供油单向阀 172,进入主活塞孔 415。 主活塞 162在油压作用下, 从阀桥 400的主活塞孔 415底面 446的缩回位 置往上移到伸出位置, 推动摇臂 210顺时针转动, 直到凸轮从动轮 235与 凸轮 230的内基圆 255接触为止。 此时, 主活塞 162与主活塞孔 415的孔 底面 446 (也就是阀桥 400) 之间形成一制动间隙 234 (与图 9的间隙 134 相对应), 打开主活塞孔 415和副活塞孔 190之间的液压通道 412的开口 472。油流进入副活塞孔 190和其上方的过渡活塞孔 191。油压克服弹簧 177 的作用力, 推动过渡活塞 161向上压靠象足垫 1142, 封闭卸油通道, 阻止 过渡活塞孔 191和副活塞孔 190内的机油向上泄漏。 这样在主活塞 162和 副活塞 160之间就形成了液压链接,主活塞 162在阀桥 400的主活塞孔 415 内的向下运动, 将以液压式的方式, 通过液压通道 412传递给在阔桥 400 和副活塞孔 190内的副活塞 160, 然后再传给下面的第一排气门 3001。
凸轮 230通过排气门驱动链开启制动排气门 3001和非制动排气门 3002的整个过程, 与第一实施例的基本相同, 在此不再复述。
上述说明披露了一种新的压缩释放型发动机制动装置和方法。 上述的 实施方式, 不应该被视为对本发明范围的限制, 而是作为代表本发明的一 些具体例证, 许多其他演变都有可能从中产生。 举例来说, 这里的压缩释 放型发动机制动装置和方法, 不但可以用于顶置凸轮式发动机, 也适用于 推杆式发动机。 还有, 单向供油阀 172可以采用不同的形式, 如球阀、 碟 阀等。 单向供油阀 172也可以安置在不同的位置, 比如安置在主活塞 162 内。 由于阀桥 400内的主活塞 162 (通过阀隙调节机构) 始终与摇臂 210 靠紧, 单向供油阀 172还可以安置在主活塞 162上方的供油通道内, 比如 说摇臂 210内的油道 214内。 单向供油阀 172只允许油流单方向从其上游 的供油通道进入主活塞 162下面的主活塞孔 415内。 此外, 除了由副活塞孔 190上方的卸油通道 197和制动支架 125形成 的卸油机构之外, 也可以是其它形式的卸油闽。 卸油机构的卸油阀在制动 凸台推动主活塞 162在制动箱体内作相对滑动时处于关闭状态。 在集成式 排气凸台的顶部进一步推动主活塞 162运动时, 卸油机构的卸油阀打开卸 油。
还有, 主活塞 162、 副活塞 160和过渡活塞 161可以采用不同的形式, 如 "H"型和 "T "型等; 制动的排气门可以是第一排气门 3001, 也可以是 第二排气门 3002。
此外, 制动支架 125的安装也可以有多种形式, 除了可以固定在发动 机的不同部件和位置, 也可以集成在发动机的运动件内。 比如第二实施例 的制动支架 125, 可以集成在摇臂 210上。 此时, 副活塞 160位于第二排 气门 3002上。过渡活塞 161除了间隙补偿之外,还起到第二主活塞的作用。 也就是说, 在制动期间, 摇臂 210上的象足 1 14推动主活塞 162, 与此同 时, 摇臂 210上的制动支架 125的象足 1 142推动过渡活塞 161。 然后, 主 活塞 162与过渡活塞 161通过液压链接一起推动副活塞 160, 打开第二排 气门 3002。 制动支架 125的连接件也可以选择不同的样式, 或采用不同的 密封措施, 如增加密封件等, 保证对卸油通道的密封。
还有, 主活塞 162堵住液压通道 412的入口 472的方式也可以不同。 比如说, 将液压通道 412的入口 472设计在主活塞 162的下面 (而不是侧 面) , 当主活塞 162移到主活塞孔底面 446的缩回位置时, 主活塞 162的 底面将入口 472盖住。
此外, 除了由阀桥 400作为制动箱体之外, 也可以有其它的形式。 比 如说固定在发动机上的顶置式制动箱体。 因此, 本发明的范围不应由上述 的具体例证来决定, 而是由权利要求来决定。

Claims

权 利 要 求 书
1. 一种压缩释放型发动机制动方法,包括一个利用发动机的排气门驱动链 开启排气门的过程, 所述的排气门驱动链包括凸轮、 摇臂和阀桥, 所述 的发动机的排气门中包括有一个第一排气门和一个第二排气门,所述的 凸轮中含有至少一个制动凸台,所述的制动凸台包括一个从凸轮的内基 圆上升到最大升程的上升段和一个保持所述的最大升程的等高段,所述 的摇臂中设置有一个供油通道, 其特征在于: 在所述的阀桥的中央向上 开口设置一个主活塞孔, 在阀桥的一端向下开口设置一个副活塞孔, 在 所述的主活塞孔和副活塞孔之间连接设置一条液压通道,在主活塞孔内 滑动式地设置一个主活塞,主活塞相对于主活塞孔具有一个伸出位置和 一个缩回位置, 在副活塞孔内滑动式地设置一个副活塞, 将主活塞的上 端与所述的摇臂连接, 在主活塞内设置一个油路, 将所述的油路的上端 与所述的摇臂中的供油通道相通, 将油路的下端与主活塞孔相通, 在主 活塞孔与供油通道之间、 或者在供油通道之内设置一个单向供油阀, 所 述的单向供油阀的供油方向是从供油通道向主活塞孔,将副活塞的下端 与所述的第一排气门相连,将阀桥另一端的下侧与所述的第二排气门相 连, 在副活塞孔所在的阀桥一端的上侧设置一个制动支架, 在所述的利 用发动机的排气门驱动链开启排气门的过程中, 首先, 通过所述的供油 通道和单向供油阀向主活塞孔供油, 将主活塞置于伸出位置, 打开主活 塞孔和副活塞孔之间的液压通道, 然后, 利用凸轮中制动凸台的上升段 驱动所述的摇臂, 使摇臂推动主活塞从伸出位置移向缩回位置, 同时利 用所述的制动支架阻止阀桥上移,利用所述的液压通道中的液压将主活 塞的运动传递给副活塞, 迫使所述的副活塞在副活塞孔内向下伸出, 打 开第一排气门, 之后, 利用凸轮中制动凸台的等高段驱动摇臂, 将主活 塞在主活塞孔内保持在缩回位置上, 阻断主活塞孔通过所述的液压通道 与副活塞孔之间的液压传递, 将副活塞保持在副活塞孔内的伸出位置, 保持第一排气门的打开状态, 同时利用制动支架承载副活塞上的制动载 荷0
2. 如权利要求 1所述的压缩释放型发动机制动方法, 其特征在于: 在副活 塞孔所在的阀桥一端内设置至少一个卸油通道,将所述的卸油通道的下 端与副活塞孔相通,利用所述的阀桥上方的制动支架的下端封闭卸油通 道的上端开口, 在阀桥向下移动时, 阀桥与制动支架分离, 打开所述的 卸油通道的上端开口。
3. 如权利要求 1所述的压缩释放型发动机制动方法, 其特征在于: 在所述 的制动凸台上设置一个下降段,将所述的下降段的起点连接在所述的等 高段的末端, 将下降段的终点回到或靠近凸轮的内基圆。
4. 如权利要求 3所述的压缩释放型发动机制动方法, 其特征在于: 在凸轮 中制动凸台经过等高段后、进入下降段的过程中,利用摇臂做反向运动, 使主活塞从缩回位置移向伸出位置, 打开液压通道在主活塞孔上的开 口, 接通主活塞孔与副活塞孔之间的液压传递, 使副活塞在第一排气门 的作用力下向縮回位置移动。
5. 如权利要求 2所述的压縮释放型发动机制动方法, 其特征在于: 在所述 的凸轮上设置集成式排气凸台, 在所述的制动凸台上设置一个缓升段, 将所述的缓升段的起点连接在所述的等高段的末端,将缓升段的终点汇 入所述的集成式排气凸台, 在凸轮中制动凸台经过等高段后、 进入缓升 段的过程中, 利用制动凸台的缓升段驱动所述的摇臂, 使摇臂通过位于 主活塞孔内缩回位置上的主活塞往下推动阀桥,使副活塞孔所在的阀桥 一端与位于其上侧的所述的制动支架分离,打幵卸油通道的上端开口卸 油, 减少副活塞孔内的液压, 使副活塞在第一排气门的作用力下在副活 塞孔内向上移往縮回位置, 使第一排气门向上移往关闭位置。
6. 如权利要求 1所述的压縮释放型发动机制动方法, 其特征在于: 所述的 利用发动机的排气门驱动链开启排气门的过程包括以下步骤: 1) 打开发动机的制动控制机构, 通过所述的供油通道和单向供油阀向 阀桥内的主活塞孔供油,
2) 主活塞在主活塞孔内置于伸出位置, 开通阔桥内的主活塞孔和副活 塞孔之间的液压通道,
3) 副活塞在副活塞孔内置于缩回位置, 副活塞下面的第一排气门处于 关闭位置,
4) 凸轮的制动凸台从内基圆向上移动, 驱动主活塞孔内的主活塞向下 往阔桥的主活塞孔内的缩回位置运动,
5) 位于副活塞孔上方的阀桥上面的制动支架阻止或限制阀桥向上运 动,
6) 主活塞的向下运动通过液压通道传递给副活塞, 阀桥的副活塞孔内 . 的副活塞向下往伸出位置运动, 打开第一排气门,
7) 凸轮的制动凸台抵达最高升程并继续保持所述的最高升程位置,
8) 主活塞在阀桥的主活塞孔内向下抵达缩回位置, 关闭主活塞孔和副 活塞孔之间的液压通道, 阻止副活塞上的液压载荷传递到,主活塞,
9) 副活塞在阔桥的副活塞孔内向下抵达伸出位置, 将副活塞下面的第 一排气门保持打开在最高制动阀升位置,
10)利用副活塞孔所在的阀桥一端上侧的制动支架来支撑第一排气门传 给副活塞的载荷,
11)凸轮的制动凸台从最高升程下降回到内基圆,
12)主活塞从阀桥的主活塞孔内的縮回位置往上移回到伸出位置, 打开 主活塞孔和副活塞孔之间的液压通道,
13)副活塞从副活塞孔内的伸出位置往上移回到缩回位置,
14)第一排气门从最高制动阀升位置往上移向关闭位置。
7. 如权利要求 2所述的压缩释放型发动机制动方法, 其特征在于: 所述的 利用发动机的排气门驱动链开启排气门的过程还包括以下步骤: 1) 关闭发动机的制动控制机构, 停止向阀桥内的主活塞孔供油,
2) 凸轮驱动阀桥的主活塞孔内的主活塞向下运动,
3) 主活塞驱动阀桥向下运动, 副活塞孔所在的阀桥一端与其上侧的制 动支架分离,
4) 打开副活塞孔上方的卸油通道卸油,
5) 副活塞从阀桥的副活塞孔内移到缩回位置。
8. 如权利要求 1所述的压缩释放型发动机制动方法, 其特征在于: 在主活 塞于主活塞孔内从缩回位置滑向伸出位置时,利用主活塞打开主活塞孔 和副活塞孔之间的液压通道,在主活塞于主活塞孔内从伸出位置滑向缩 回位置时, 利用主活塞关闭主活塞孔和副活塞孔之间的液压通道。
9. 如权利要求 1所述的压缩释放型发动机制动方法, 其特征在于: 利用一 个预紧弹簧在排气门驱动链内部保持由主活塞的缩回位置与伸出位置 生成的排气门驱动链制动间隙, 消除排气门驱动链内部的不跟随和冲 击。
10. 一种压缩释放型发动机制动装置, 包括制动控制机构和制动驱动机 构, 其特征在于: 所述的制动控制机构包括一个与液压产生装置相连接 的控制阀, 制动驱动机构包括制动箱体、 供油机构、 卸油机构和制动凸 轮, 所述的制动箱体内设置有主活塞孔和副活塞孔, 所述的主活塞孔和 副活塞孔之间设置有一条连通的液压通道,主活塞孔内滑动式地设置有 主活塞, 副活塞孔内滑动式地设置有副活塞, 所述的供油机构包括供油 通道和单向供油阀,所述的制动控制机构中的控制阀与所述的供油通道 的入口连接, 供油通道的出口与主活塞孔连接, 所述的单向供油阀设置 在供油通道或者供油通道与主活塞孔之间,单向供油阀的供油方向是从 供油通道进入主活塞孔, 所述的卸油机构包括一个卸油阀, 所述的卸油 阀与副活塞孔连通, 所述的制动凸轮中含有至少一个制动凸台。
11. 如权利要求 10所述的压缩释放型发动机制动装置,其特征在于:所 述的制动箱体由阀桥构成,所述的主活塞孔设置在所述的阀桥中央的一 个向上开口内, 所述的副活塞孔设置在阀桥的一端的一个向下开口内, 所述的液压通道设置在阀桥内并连通主活塞孔和副活塞孔,所述的主活 塞设置在主活塞孔内, 所述的副活塞设置在副活塞孔内, 主活塞的上端 与发动机的摇臂连接, 所述的摇臂中设置有一个供油通道, 主活塞内设 置有一个油路, 所述的油路的上端与所述的摇臂中的供油通道相通, 油 路的下端与主活塞孔相通,所述的单向供油阀设置在主活塞孔与供油通 道之间或者供油通道之内,所述的单向供油阀的供油方向是从供油通道 向主活塞孔, 副活塞孔所在的阀桥一端的上侧设置有一个制动支架, 副 活塞孔所在的阀桥一端设置有至少一个卸油通道,所述的卸油通道的一 端与副活塞孔相通, 卸油通道的另一端由制动支架的下端封闭, 所述的 制动凸轮上设置有集成式排气凸台。
12. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:副 活塞的下端与发动机排气门中的一个第一排气门相连, 阀桥另一端的下 侧与发动机排气门中的一个第二排气门相连。
13. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动支架固定在发动机上, 所述的制动支架包括连接件, 所述的连 接件位于阀桥的上方。
14. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动支架集成在摇臂上, 所述的制动支架包括连接件, 所述的连接 件位于阀桥的上方。
15. 如权利要求 13或者 14所述的压缩释放型发动机制动装置, 其特征 在于: 所述的制动支架的连接件包括过渡活塞, 所述的过渡活塞滑动式 地安置在阀桥的过渡活塞孔内,所述的过渡活塞孔位于所述的副活塞孔 之上。
16. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动凸台中包括有一个压縮释放凸台,所述的压缩释放凸台在发动 机的压縮冲程的后期从凸轮的内基圆幵始上升, 并在发动机的压缩上止 点附近达到最高位置,在发动机的膨胀冲程的前期下降回到或靠近凸轮 的内基圆。
17. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动凸台中包括有一个压缩释放凸台和一个排气再循环凸台,所述 的压縮释放凸台在发动机的压缩冲程的后期从凸轮的内基圆开始上升, 并在发动机的压縮上止点附近达到最高位置,在发动机的膨胀冲程的前 期下降回到或靠近凸轮的内基圆,所述的排气再循环凸台在发动机的进 气冲程的后期从凸轮的内基圆开始上升,在发动机的压缩冲程的前期下 降回到凸轮的内基圆。
18. 如权利要求 11所述的压縮释放型发动机制动装置,其特征在于:在 所述的凸轮上设置有一个集成式排气凸台和制动凸台,所述的制动凸台 中包括有一个压缩释放凸台,所述的压缩释放凸台在发动机的压缩冲程 的后期从凸轮的内基圆开始上升,并在发动机的压缩冲程上止点之前上 升到最高位置,在发动机的压缩冲程的剩余期间和发动机的膨胀冲程的 初期保持所述的最高位置,在发动机的膨胀冲程的剩余期间下降回到凸 轮的内基圆或汇入集成式排气凸台,所述的集成式排气凸台由底部和顶 部组成, 集成式排气凸台的底部与制动凸台接近同高, 集成式排气凸台 的顶部与发动机的常规凸台接近相同。
19. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动凸台中包括有一个排气再循环凸台,所述的排气再循环凸台在 发动机的进气冲程的后期从凸轮的内基圆开始上升,在发动机的压縮冲 程的前期下降回到凸轮的内基圆。
20. 如权利要求 11所述的压缩释放型发动机制动装置,其特征在于:所 述的制动驱动机构中设置有一个自动间隙补偿机构。
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