CN109458238B - Multi-mode valve mechanism and control method thereof - Google Patents

Multi-mode valve mechanism and control method thereof Download PDF

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Publication number
CN109458238B
CN109458238B CN201910004412.5A CN201910004412A CN109458238B CN 109458238 B CN109458238 B CN 109458238B CN 201910004412 A CN201910004412 A CN 201910004412A CN 109458238 B CN109458238 B CN 109458238B
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CN
China
Prior art keywords
rocker arm
shaft sleeve
stroke
exhaust
braking
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CN201910004412.5A
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Chinese (zh)
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CN109458238A (en
Inventor
崔靖晨
田华
隆武强
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Dalian University of Technology
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Dalian University of Technology
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/06—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like the cams, or the like, rotating at a higher speed than that corresponding to the valve cycle, e.g. operating fourstroke engine valves directly from crankshaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/181—Centre pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/36—Valve-gear or valve arrangements, e.g. lift-valve gear peculiar to machines or engines of specific type other than four-stroke cycle
    • F01L1/38—Valve-gear or valve arrangements, e.g. lift-valve gear peculiar to machines or engines of specific type other than four-stroke cycle for engines with other than four-stroke cycle, e.g. with two-stroke cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/46—Component parts, details, or accessories, not provided for in preceding subgroups
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

A multi-mode valve actuating mechanism and a control method thereof belong to the field of engine valve actuating mechanisms, cylinder deactivation and auxiliary braking. The device comprises a first shaft sleeve driven by a first camshaft through a spline, a second shaft sleeve driven by a second camshaft through a spline, a switching mechanism, a brake rocker arm and the like. According to the invention, the braking rocker arm is arranged, and the braking rocker arm is kept in a failure state in the switching stage of the shaft sleeve corresponding to the braking rocker arm, so that the shaft sleeve is switched in the non-common base circle section of the cam corresponding to the braking rocker arm; by controlling the switching mechanism and the brake rocker arm, the flexible switching of various modes such as four-stroke stepped driving, four-stroke stepped braking, two-stroke stepped braking and the like of the engine is realized, and the economy, emission, safety and transportation capacity of the vehicle are improved; the mechanism has compact structure and meets the arrangement requirement of the engine with small cylinder spacing.

Description

Multi-mode valve mechanism and control method thereof
Technical Field
The invention relates to a multi-mode valve actuating mechanism and a control method thereof, belonging to the field of engine valve actuating mechanisms, cylinder deactivation and auxiliary braking.
Background
With the rapid increase of the engine reserve, the problems of energy and environment and the driving safety become one of the major problems restricting the sustainable development of China. Cylinder deactivation technology is of great interest because it can effectively reduce engine oil consumption and emissions. The miniaturization (Down-size) and low-speed (Down-speed) of the engine are the development trends of recognized energy conservation and emission reduction. On the other hand, in engine braking, the smaller the cylinder diameter and the lower the rotation speed, the poorer the braking effect. Under the large background that the braking capability of a vehicle is continuously weakened, the freight requirement is continuously increased, the road environment is complex and changeable, the safety of the vehicle is more and more emphasized by people, and an auxiliary braking system is listed as one of the necessary accessories of the vehicle in more and more countries, the realization of an efficient graded braking mode is imperative.
In response to the above problems, applicants have proposed a multi-mode engine that differentially optimizes engine performance over the full range of drive-brake operating conditions. Under the driving working condition, a four-stroke grading driving mode is adopted to meet the requirements of low oil consumption and low emission; under the condition of small load braking of the vehicle, a four-stroke graded braking mode is adopted, so that the requirements of the vehicle on light load, short slope descending or gentle slope are met; under the working condition of heavy load braking of the vehicle, a two-stroke graded braking mode is adopted, the requirements of the vehicle during heavy load, long downward slope or steep slope are met, and the requirement of high-efficiency graded braking is met; under the emergency situations of failure of a vehicle main brake and/or other brake systems and the like, different emergency brake modes are adopted to meet the braking requirements of the emergency situations. Based on the above, the key point for realizing the multi-mode engine is the development of the multi-mode valve actuating mechanism which can realize the flexible switching among a plurality of modes such as a four-stroke stepped driving mode, a four-stroke stepped braking mode, a two-stroke stepped braking mode and the like of the engine.
Because most of the existing practical variable valve actuating mechanisms are used for engines with four-stroke driving modes and cannot meet the requirements of multi-mode engines, the development of a set of valve actuating mechanism which has high reliability and a simple and compact structure and meets the requirements of the multi-mode engines is imperative.
Disclosure of Invention
The invention aims to: by designing a multi-mode valve actuating mechanism and a control method thereof, the multi-mode valve actuating mechanism is used for realizing that: (a) in order to achieve the operation of low oil consumption, low emission and high-efficiency graded braking of the engine, the valve train is required to realize multiple modes such as four-stroke graded driving, four-stroke graded braking, two-stroke graded braking and the like. (b) In order to meet the arrangement requirement of a multi-cylinder engine, the invention is required to be compact in structure.
The technical scheme adopted by the invention is as follows: the multi-mode valve actuating mechanism comprises a first cam shaft, a second cam shaft, a first shaft sleeve, a second shaft sleeve, a switching mechanism, a brake rocker arm, an exhaust valve assembly, an intake valve assembly and the like. The first camshaft drives the first shaft sleeve to rotate through the spline, and the second camshaft drives the second shaft sleeve to rotate through the spline.
The first shaft sleeve is provided with a first air inlet two-stroke cam, a first air inlet four-stroke cam, a second air inlet two-stroke cam, a second air inlet four-stroke cam, a first switching groove and a second switching groove, and the second shaft sleeve is provided with a first exhaust two-stroke cam, a first exhaust four-stroke cam, a second exhaust two-stroke cam, a second exhaust four-stroke cam, a third switching groove and a fourth switching groove.
The first air inlet rocker arm corresponds to the first air inlet valve assembly, the second air inlet rocker arm corresponds to the second air inlet valve assembly, the first exhaust rocker arm corresponds to the first exhaust valve assembly, and the second exhaust rocker arm corresponds to the second exhaust valve assembly.
The first and second bushings each have two axial positions.
When the first shaft sleeve is located at the first position, the first air inlet four-stroke cam drives the first air inlet rocker arm, and the second air inlet four-stroke cam drives the second air inlet rocker arm.
When the first shaft sleeve is located at the second position, the first air inlet two-stroke cam drives the first air inlet rocker arm, and the second air inlet two-stroke cam drives the second air inlet rocker arm.
When the second sleeve is at the first position, the first exhaust four-stroke cam drives the first exhaust rocker arm, and the second exhaust four-stroke cam drives the second exhaust rocker arm.
When the second sleeve is at the second position, the first exhaust two-stroke cam drives the first exhaust rocker arm, and the second exhaust two-stroke cam drives the second exhaust rocker arm.
When the first shaft sleeve is switched from the first position to the second position, the second switching mechanism works. When the first sleeve is switched from the second position to the first position, the first switching mechanism works. When the second shaft sleeve is switched from the first position to the second position, the third switching mechanism works. When the second sleeve is switched from the second position to the first position, the fourth switching mechanism operates.
At least one of the first exhaust rocker arm and the second exhaust rocker arm is a brake rocker arm, and the reset spring drives the brake rocker arm to contact with the corresponding cam.
The brake rocker arm has two working states: when the brake rocker arm is in an effective state, the brake rocker arm drives the corresponding valve assembly; when the brake rocker arm is in a failure state, the brake rocker arm does not drive the corresponding valve assembly.
The non-braking rocker arm always drives the corresponding valve assembly.
The first switching mechanism, the second switching mechanism, the third switching mechanism and the fourth switching mechanism are switching components, and the switching components at least comprise telescopic pins. The telescopic state of the pin is controlled by electromagnetism, hydraulic pressure or gas.
The brake rocker arm comprises at least a locking or switch fulcrum type structure.
The locking type brake rocker arm is provided with a first rod, a second rod and a locking mechanism arranged between the first rod and the second rod, wherein the cam drives the input end of the first rod, the output end of the first rod drives the input end of the second rod, and the output end of the second rod drives the corresponding valve assembly.
The switch fulcrum type brake rocker arm is provided with a rocker arm body and a brake fulcrum arranged on the rocker arm body or a brake fulcrum arranged on the fixed bracket. The brake fulcrum at least comprises a hydraulic piston type brake fulcrum or a locking type brake fulcrum.
The first intake four-stroke cam and/or the second intake four-stroke cam has a projection at least in the intake stroke; the first exhaust four-stroke cam and/or the second exhaust four-stroke cam has a projection at least in the exhaust stroke; at least one of the first intake two-stroke cam, the second intake two-stroke cam, the first exhaust two-stroke cam, and the second exhaust two-stroke cam has a projection near a compression top dead center, at least one of the cams has a projection near an intake/exhaust top dead center, at least one of the cams has a projection near an intake/compression bottom dead center, and at least one of the cams has a projection near an expansion/exhaust bottom dead center.
When the ignition interval of two adjacent cylinders is larger than the switching interval of the switching slot, the shaft sleeves of the two adjacent cylinders can share the switching mechanism.
When the engine needs to operate in a four-stroke driving mode, the first shaft sleeve is located at the first position, the second shaft sleeve is located at the first position, the brake rocker arm is in an effective state, and fuel is supplied into the cylinder.
When the engine needs to operate in the cylinder deactivation mode, the first shaft sleeve is located at the second position, the second shaft sleeve is located at the second position, the brake rocker arm is in a failure state, and fuel is not supplied into the cylinder.
When the engine needs the first four-stroke braking mode, the first shaft sleeve is at the first position, the second shaft sleeve is at the first position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder.
When the engine needs the second four-stroke braking mode to operate, the first shaft sleeve is in the first position, the second shaft sleeve is in the first position, the braking rocker arm is in a failure state, and fuel is not supplied into the cylinder.
When the engine needs a third four-stroke braking mode to operate, the first shaft sleeve is at the first position, the second shaft sleeve is at the second position, the braking rocker arm is in a failure state, and fuel is not supplied into the cylinder.
When the engine needs a fourth four-stroke braking mode to operate, the first shaft sleeve is at the second position, the second shaft sleeve is at the first position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder.
When the engine needs a fifth four-stroke braking mode to operate, the first shaft sleeve is at the second position, the second shaft sleeve is at the first position, the braking rocker arm is in a failure state, and fuel is not supplied into the cylinder.
When the engine needs a sixth four-stroke braking mode to operate, the first shaft sleeve is at the first position, the second shaft sleeve is at the second position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder.
When the engine needs a two-stroke braking mode to operate, the first shaft sleeve is at the second position, the second shaft sleeve is at the second position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder.
When the engine needs the four-stroke emergency braking mode to operate, the first shaft sleeve is located at the first position, the second shaft sleeve is located at the second position, the braking rocker arm is located at the effective state, and fuel is supplied to the cylinder.
When the engine needs a two-stroke emergency braking mode to operate, the first shaft sleeve is located at the second position, the second shaft sleeve is located at the second position, the braking rocker arm is in an effective state, and fuel is supplied to the cylinder.
For a multi-cylinder machine, a cylinder deactivation mode is adopted by a non-working cylinder, and a driving mode or a braking mode is adopted by a working cylinder.
For a multi-cylinder machine, in the braking mode, the cylinders adopt the same or different braking modes.
The invention has the beneficial effects that: the multi-mode valve actuating mechanism mainly comprises a first shaft sleeve driven by a first cam shaft through a spline, a second shaft sleeve driven by a second cam shaft through a spline, a switching mechanism, a brake rocker arm and the like. The first shaft sleeve is provided with a first air inlet two-stroke cam, a first air inlet four-stroke cam, a second air inlet two-stroke cam, a second air inlet four-stroke cam and the like, and the second shaft sleeve is provided with a first exhaust two-stroke cam, a first exhaust four-stroke cam, a second exhaust two-stroke cam, a second exhaust four-stroke cam and the like. (a) By arranging the braking rocker arm, the braking rocker arm is kept in a failure state in the switching stage of the braking rocker arm corresponding to the shaft sleeve, and the shaft sleeve is switched in the non-public base circle section of the cam corresponding to the braking rocker arm. (b) By controlling the switching component and the brake rocker arm, the switching of multiple modes such as four-stroke stepped driving, four-stroke stepped braking, two-stroke stepped braking and the like is realized, and the low oil consumption, low emission and high-efficiency stepped braking of the engine are achieved. (c) Compared with the arrangement mode that one cam drives a plurality of valve assemblies, the arrangement mode has the advantages that the cam stress is small, the cam thickness is small, the length of the shaft sleeve and the moving distance of the shaft sleeve are short, and the arrangement requirement of a multi-cylinder engine on a valve actuating mechanism is met; (d) for the engine with the ignition interval of two adjacent cylinders larger than the switching interval of the switching slot, the shaft sleeves of the two adjacent cylinders can share the switching mechanism, so that the number of the switching mechanism is reduced, and the cost is reduced.
Drawings
The invention is further described with reference to the following figures and examples.
FIG. 1 is a first schematic of a multi-mode valve train.
FIG. 2 is a second schematic of a multi-mode valve train.
Fig. 3 is a schematic view of the first hub being unfolded.
Fig. 4 is a schematic view of the second bushing being unfolded.
Fig. 5 is a schematic view showing the development of adjacent cylinder liners sharing a switching mechanism.
In the figure: 101. a first camshaft; 102. a second camshaft; 201. a first bushing; 202. a second shaft sleeve; 301. a first switching slot; 302. a second switching slot; 303. a third switching slot; 304. a fourth switching slot; 401. a first switching mechanism; 402. a second switching mechanism; 403. a third switching mechanism; 404. a fourth switching mechanism; 51A, a first intake rocker arm; 52A, a second intake rocker arm; 51B, a first exhaust rocker arm; 52B, a second exhaust rocker arm; 51D, a brake fulcrum; 612A, a first intake two-stroke cam; 614A, a first intake four-stroke cam; 622A, a second intake two-stroke cam; 624A, a second intake four-stroke cam; 612B, a first exhaust two-stroke cam; 614B, a first exhaust four-stroke cam; 622B, a second exhaust two-stroke cam; 624B, a second exhaust four-stroke cam; 71A, a first intake valve assembly; 72A, a second intake valve assembly; 71B, a first exhaust valve assembly; 72B, a second exhaust valve assembly; n1, cylinder number one; n2, cylinder number two.
Detailed Description
The invention relates to a multi-mode valve actuating mechanism which comprises a first camshaft 101, a second camshaft 102, a first shaft sleeve 201, a second shaft sleeve 202, an exhaust valve assembly, an intake valve assembly and the like. The first camshaft 101 drives the first sleeve 201 to rotate through the spline, and the second camshaft 102 drives the second sleeve 202 to rotate through the spline. The first boss 201 is provided with a first intake two-stroke cam 612A, a first intake four-stroke cam 614A, a second intake two-stroke cam 622A, a second intake four-stroke cam 624A, a first switching groove 301, and a second switching groove 302, and the second boss 202 is provided with a first exhaust two-stroke cam 612B, a first exhaust four-stroke cam 614B, a second exhaust two-stroke cam 622B, a second exhaust four-stroke cam 624B, a third switching groove 303, and a fourth switching groove 304. The first intake rocker arm 51A corresponds to a first intake valve assembly 71A, the second intake rocker arm 52A corresponds to a second intake valve assembly 72A, the first second exhaust rocker arm 51B corresponds to a first exhaust valve assembly 71B, and the second exhaust rocker arm 52B corresponds to a second exhaust valve assembly 72B.
The first intake four-stroke cam 614A and/or the second intake four-stroke cam 624A have/has a protrusion at least in the intake stroke; the first exhaust four-stroke cam 614B and/or the second exhaust four-stroke cam 624B have a protrusion at least in the exhaust stroke; at least one of the first intake two-stroke cam 612A, the second intake two-stroke cam 622A, the first exhaust two-stroke cam 612B, and the second exhaust two-stroke cam 622B has a projection near the compression top dead center, at least one of the cams has a projection near the intake/exhaust top dead center, at least one of the cams has a projection near the intake/compression bottom dead center, and at least one of the cams has a projection near the expansion/exhaust bottom dead center. Fig. 1 and 2 show examples in which the first intake four-stroke cam 614A and the second intake four-stroke cam 624A each have a protrusion in the intake stroke, the first exhaust four-stroke cam 614B and the second exhaust four-stroke cam 624B each have a protrusion in the exhaust stroke, the first intake two-stroke cam 612A and the first intake four-stroke cam 614A each have a protrusion near each bottom dead center, the second exhaust two-stroke cam 622B has a protrusion near each bottom dead center, and the first exhaust two-stroke cam 612B has a protrusion near each top dead center and near each bottom dead center.
The first 201 and second 202 sleeves each have two axial positions. When the first sleeve 201 is in the first position, the first intake four-stroke cam 614A drives the first intake rocker arm 51A, and the second intake four-stroke cam 624A drives the second intake rocker arm 52A. When the first sleeve 201 is in the second position, the first intake two-stroke cam 612A drives the first intake rocker arm 51A, and the second intake two-stroke cam 622A drives the second intake rocker arm 52A. With the second boss 202 in the first position, the first exhaust four-stroke cam 614B drives the first exhaust rocker arm 51B, and the second exhaust four-stroke cam 624B drives the second exhaust rocker arm 52B. With the second boss 202 in the second position, the first exhaust two-stroke cam 612B drives the first exhaust rocker arm 51B, and the second exhaust two-stroke cam 622B drives the second exhaust rocker arm 52B.
When the first sleeve 201 is switched from the first position to the second position, the second switching mechanism 402 operates. When the first sleeve 201 is switched from the second position to the first position, the first switching mechanism 401 operates. When the second bushing 202 is switched from the first position to the second position, the third switching mechanism 403 operates. When the second bushing 202 is switched from the second position to the first position, the fourth switching mechanism 404 is operated.
The first switching mechanism 401, the second switching mechanism 402, the third switching mechanism 403, and the fourth switching mechanism 404 are switching elements, and the switching elements include retractable pins. The telescopic state of the pin is controlled by electromagnetism, hydraulic pressure or gas.
The conventional bushing switching interval must be a common base circle segment of all cams on the bushing. In the invention, the common base circle section of all cams on at least one shaft sleeve is smaller, and the switching requirement of the shaft sleeve cannot be met, so that at least one rocker arm needs to be selected from the first exhaust rocker arm 51B and the second exhaust rocker arm 52B and is set as a brake rocker arm, and a return spring is arranged to drive the brake rocker arm to be in contact with the corresponding cam. And at the corresponding shaft sleeve switching stage, the brake rocker arm is kept in a failure state, and the shaft sleeve switching of the non-common base circle section of the cam corresponding to the brake rocker arm is realized.
The brake rocker arm has two operating states. When the brake rocker arm is in an effective state, the brake rocker arm drives the corresponding valve assembly; when the brake rocker arm is in a failure state, the brake rocker arm does not drive the corresponding valve assembly.
Taking the embodiment shown in fig. 1 and 2 as an example, the switching section of the first sleeve 201 is within the common base circle segment of the first intake two-stroke cam 612A, the first intake four-stroke cam 614A, the second intake two-stroke cam 622A and the second intake four-stroke cam 624A. The common base circle segment of the first exhaust two-stroke cam 612B, the first exhaust four-stroke cam 614B, the second exhaust two-stroke cam 622B, and the second exhaust four-stroke cam 624B is very small, and cannot meet the switching requirement of the second hub 202. By changing the first exhaust rocker arm 51B to a brake rocker arm, the first exhaust rocker arm 51B is maintained in a deactivated state during the respective sleeve switching phase, achieving a non-common base circle segment switching sleeve for the first exhaust two-stroke cam 612B. That is, the maximum switchable interval is determined based on the common base circle segment of the first exhaust four-stroke cam 614B, the second exhaust two-stroke cam 622B, and the second exhaust four-stroke cam 624B.
The brake rocker arm comprises at least a locking or switch fulcrum type structure. The locking type brake rocker arm is provided with a first rod, a second rod and a locking mechanism arranged between the first rod and the second rod, wherein the cam drives the input end of the first rod, the output end of the first rod drives the input end of the second rod, and the output end of the second rod drives the corresponding valve assembly. The switch fulcrum type brake rocker arm is provided with a rocker arm body and a brake fulcrum arranged on the rocker arm body or a brake fulcrum arranged on the fixed bracket; the brake fulcrum at least comprises a hydraulic piston type brake fulcrum or a locking type brake fulcrum. Fig. 1 and 2 show a schematic view of a pivot-point brake rocker with a brake pivot arranged on a fixed bracket.
The switching section of the switching groove is determined based on the circumferential position of the contact point of the cam with the rocker arm, the rotational direction of the camshaft, and the circumferential position of the switching mechanism. When any one of the above conditions is changed, other conditions need to be adjusted. Therefore, in an actual situation, it is necessary to determine the common base circle segment of the cam, the rotation direction of the camshaft, and the circumferential position of the cam output point, and to adjust the switching section of the switching groove and the circumferential position of the switching mechanism, depending on the actual model.
In the present embodiment, the first camshaft 101 rotates counterclockwise, the second camshaft 102 rotates clockwise, and fig. 3 and 4 are schematic development views of the first sleeve 201 and the second sleeve 202, respectively. Further, the first switching groove 301 and the second switching groove 302 may be separated from each other, as in fig. 3; by combining the common guide sections of the two, the two can be combined into one. The third switching groove 303 and the second switching groove 304 may be designed to be separated or combined.
When the ignition interval of two adjacent cylinders is larger than the switching interval of the switching slot, the two adjacent cylinders can share the same group of switching mechanisms (2), the advantages of reducing the number of the switching mechanisms and reducing the cost are that the axial positions of the two shaft sleeves can only be in the first position or in the second position. Taking the first shaft sleeves of 1 cylinder and 2 cylinders of an in-line 6-cylinder machine with the ignition sequence of 1-4-2-6-3-5 as an example, the left side N1 is a first cylinder, the right side N2 is a second cylinder, and the shaft sleeves of the two cylinders share the first switching mechanism 401 and the second switching mechanism 402; the first switching mechanism 401 acts on the first switching groove 301 of the first cylinder number N1 and the first switching groove 301 of the second cylinder number N2; likewise, the second switching mechanism 402 acts on the second switching groove 302 of the first cylinder number N1 and the second switching groove 302 of the second cylinder number N2. Fig. 5 is a schematic view of the bushing in an expanded configuration.
Note that: the switching slots in fig. 3-5 all show only the switching segment and no transition segment.
By controlling the switching assembly and the brake rocker arm, the invention can realize multiple modes.
When the engine needs to operate in the four-stroke driving mode, the first sleeve 201 is in the first position, the second sleeve 202 is in the first position, the brake rocker arm is in an active state, and fuel is supplied into the cylinder.
When the engine requires a cylinder deactivation mode of operation, the first sleeve 201 is in the second position, the second sleeve 202 is in the second position, the brake rocker arm is in a deactivated state, and no fuel is supplied to the cylinder.
When the engine requires the first type of four-stroke braking mode of operation, the first sleeve 201 is in the first position, the second sleeve 202 is in the first position, the brake rocker arm is in an active state, and no fuel is supplied to the cylinder.
When the engine requires the second type of four-stroke braking mode of operation, the first sleeve 201 is in the first position, the second sleeve 202 is in the first position, the brake rocker arm is in a deactivated state, and no fuel is supplied to the cylinder.
When the engine requires the third type of four-stroke braking mode of operation, the first sleeve 201 is in the first position, the second sleeve 202 is in the second position, the brake rocker arm is in a deactivated state, and no fuel is supplied to the cylinder.
When the engine needs to operate in the fourth type four-stroke braking mode, the first sleeve 201 is in the second position, the second sleeve 202 is in the first position, the brake rocker arm is in an active state, and no fuel is supplied into the cylinder.
When the engine requires the fifth type of four-stroke braking mode of operation, the first sleeve 201 is in the second position, the second sleeve 202 is in the first position, the brake rocker arm is in a deactivated state, and no fuel is supplied to the cylinder.
When the engine requires the sixth four-stroke braking mode of operation, the first sleeve 201 is in the first position, the second sleeve 202 is in the second position, the brake rocker arm is in the active state, and no fuel is supplied to the cylinder.
When the engine requires a two-stroke braking mode of operation, the first sleeve 201 is in the second position, the second sleeve 202 is in the second position, the brake rocker arm is active and no fuel is supplied to the cylinder.
When the engine needs to operate in the four-stroke emergency braking mode, the first sleeve 201 is in the first position, the second sleeve 202 is in the second position, the brake rocker arm is in an active state, and fuel is supplied to the cylinder.
When the engine needs to operate in the two-stroke emergency braking mode, the first sleeve 201 is in the second position, the second sleeve 202 is in the second position, the brake rocker arm is in the active state, and fuel is supplied to the cylinder.
The various braking modes can realize the output of different braking powers of the engine. The modes are selected according to the vehicle requirements.
When the engine is in a driving mode, fuel oil is combusted to do positive work, and the engine outputs power to drive wheels to run. The engine burns before the compression top dead center to do negative work in various four-stroke emergency braking modes; the engine is in a two-stroke emergency braking mode, combustion is carried out before each top dead center to do negative work, and the engine generates resistance to realize the retarding and braking under the emergency condition of the vehicle. The emergency braking mode is mainly used for slowing and braking the vehicle and the like aiming at the conditions that a main braking system of the vehicle fails, other auxiliary braking systems fail or the braking power is insufficient and the like, so that the safety of the vehicle is ensured.
As the shaft sleeves of the cylinders are independently controllable, all the cylinders can be divided into a non-working cylinder and a working cylinder for the multi-cylinder engine, the non-working cylinder adopts a cylinder deactivation mode, and the working cylinder adopts a driving mode or a braking mode, so that the power output of the engine can be controlled in a grading manner. If the vehicle needs less power, namely the engine is in a low-load operation state, a four-stroke graded cylinder deactivation driving technology can be adopted, namely a cylinder deactivation mode is adopted for one part of cylinders, a four-stroke driving mode is adopted for the other cylinders, and the cylinder deactivation rate is changed along with the change of the load of the engine, so that the oil consumption and the emission of the engine can be obviously reduced. And if a part of cylinders adopt a cylinder deactivation mode, and other cylinders adopt a braking mode, the engine can continuously and adjustably output braking power according to the running condition of the vehicle. In addition, in the braking mode, the cylinders adopt the same or different braking modes. Under each braking mode, the engine can be matched with an EGR system, a turbocharging system, a butterfly valve arranged on an exhaust pipe and the like to obtain different braking powers, so that the engine can continuously and adjustably output the braking power according to the running condition of the vehicle.

Claims (7)

1. A multi-mode valve train mechanism includes an exhaust valve assembly and an intake valve assembly, characterized by:
the first camshaft (101) drives the first shaft sleeve (201) to rotate through a spline, and the second camshaft (102) drives the second shaft sleeve (202) to rotate through the spline;
the first shaft sleeve (201) is provided with a first air inlet two-stroke cam (612A), a first air inlet four-stroke cam (614A), a second air inlet two-stroke cam (622A), a second air inlet four-stroke cam (624A), a first switching groove (301) and a second switching groove (302), and the second shaft sleeve (202) is provided with a first air exhaust two-stroke cam (612B), a first air exhaust four-stroke cam (614B), a second air exhaust two-stroke cam (622B), a second air exhaust four-stroke cam (624B), a third switching groove (303) and a fourth switching groove (304);
the first intake four-stroke cam (614A) and/or the second intake four-stroke cam (624A) has a projection at least in the intake stroke; the first exhaust four-stroke cam (614B) and/or the second exhaust four-stroke cam (624B) has a protrusion at least in the exhaust stroke; at least one of the first intake two-stroke cam (612A), the second intake two-stroke cam (622A), the first exhaust two-stroke cam (612B), and the second exhaust two-stroke cam (622B) has a protrusion near a compression top dead center, at least one of the cams has a protrusion near an intake/exhaust top dead center, at least one of the cams has a protrusion near an intake/compression bottom dead center, and at least one of the cams has a protrusion near an expansion/exhaust bottom dead center;
the first intake rocker arm (51A) corresponds to a first intake valve assembly (71A), the second intake rocker arm (52A) corresponds to a second intake valve assembly (72A), the first exhaust rocker arm (51B) corresponds to a first exhaust valve assembly (71B), and the second exhaust rocker arm (52B) corresponds to a second exhaust valve assembly (72B);
the first shaft sleeve (201) and the second shaft sleeve (202) both have two axial positions;
when the first bushing (201) is at the first position, the first air inlet four-stroke cam (614A) drives the first air inlet rocker arm (51A), and the second air inlet four-stroke cam (624A) drives the second air inlet rocker arm (52A);
when the first shaft sleeve (201) is at the second position, the first air inlet two-stroke cam (612A) drives the first air inlet rocker arm (51A), and the second air inlet two-stroke cam (622A) drives the second air inlet rocker arm (52A);
when the second shaft sleeve (202) is at the first position, the first exhaust four-stroke cam (614B) drives the first exhaust rocker arm (51B), and the second exhaust four-stroke cam (624B) drives the second exhaust rocker arm (52B);
when the second shaft sleeve (202) is at the second position, the first exhaust two-stroke cam (612B) drives the first exhaust rocker arm (51B), and the second exhaust two-stroke cam (622B) drives the second exhaust rocker arm (52B);
when the first shaft sleeve (201) is switched from the first position to the second position, the second switching mechanism (402) works; when the first shaft sleeve (201) is switched from the second position to the first position, the first switching mechanism (401) works; when the second shaft sleeve (202) is switched from the first position to the second position, the third switching mechanism (403) works; when the second shaft sleeve (202) is switched from the second position to the first position, the fourth switching mechanism (404) works;
at least one of the first exhaust rocker arm (51B) and the second exhaust rocker arm (52B) is a brake rocker arm, and the reset spring drives the brake rocker arm to be in contact with the corresponding cam; the brake rocker arm has two working states;
when the brake rocker arm is in an effective state, the brake rocker arm drives the corresponding valve assembly;
when the brake rocker arm is in a failure state, the brake rocker arm does not drive the corresponding valve assembly;
in the shaft sleeve switching stage, the brake rocker arm is kept in a failure state;
the non-braking rocker arm always drives the corresponding valve assembly.
2. The multi-mode valve train of claim 1, wherein: the first switching mechanism (401), the second switching mechanism (402), the third switching mechanism (403) and the fourth switching mechanism (404) are switching assemblies, and the switching assemblies at least comprise telescopic pins; the telescopic state of the pin is controlled by electromagnetism, hydraulic pressure or gas.
3. The multi-mode valve train of claim 1, wherein: the brake rocker arm at least comprises a locking type or switch fulcrum type structure;
the locking type brake rocker arm is provided with a first rod, a second rod and a locking mechanism arranged between the first rod and the second rod, wherein the cam drives the input end of the first rod, the output end of the first rod drives the input end of the second rod, and the output end of the second rod drives the corresponding valve assembly;
the switch fulcrum type brake rocker arm is provided with a rocker arm body and a brake fulcrum arranged on the rocker arm body or a brake fulcrum arranged on the fixed bracket; the brake fulcrum at least comprises a hydraulic piston type brake fulcrum or a locking type brake fulcrum.
4. The multi-mode valve train of claim 1, wherein: when the ignition interval of two adjacent cylinders is larger than the switching interval of the switching slot, the shaft sleeves of the two adjacent cylinders can share the switching mechanism.
5. The method of controlling a multi-mode valve train of claim 1, wherein:
when the engine needs to operate in a four-stroke driving mode, the first shaft sleeve (201) is at a first position, the second shaft sleeve (202) is at the first position, the brake rocker arm is in an effective state, and fuel is supplied into a cylinder;
when the engine needs to operate in a cylinder deactivation mode, the first shaft sleeve (201) is in the second position, the second shaft sleeve (202) is in the second position, the brake rocker arm is in a failure state, and fuel is not supplied into a cylinder;
when the engine needs a first four-stroke braking mode to operate, the first shaft sleeve (201) is at a first position, the second shaft sleeve (202) is at a first position, the braking rocker arm is in an effective state, and fuel is not supplied to a cylinder;
when the engine needs a second four-stroke braking mode to operate, the first shaft sleeve (201) is at the first position, the second shaft sleeve (202) is at the first position, the braking rocker arm is in a failure state, and fuel is not supplied to the cylinder;
when the engine needs a third four-stroke braking mode to operate, the first shaft sleeve (201) is at the first position, the second shaft sleeve (202) is at the second position, the braking rocker arm is in a failure state, and fuel is not supplied to the cylinder;
when the engine needs a fourth four-stroke braking mode to operate, the first shaft sleeve (201) is at the second position, the second shaft sleeve (202) is at the first position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder;
when the engine needs a fifth four-stroke braking mode to operate, the first shaft sleeve (201) is at the second position, the second shaft sleeve (202) is at the first position, the braking rocker arm is in a failure state, and fuel is not supplied to the cylinder;
when the engine needs a sixth four-stroke braking mode to operate, the first shaft sleeve (201) is at the first position, the second shaft sleeve (202) is at the second position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder;
when the engine needs to operate in a four-stroke emergency braking mode, the first shaft sleeve (201) is located at a first position, the second shaft sleeve (202) is located at a second position, the braking rocker arm is in an effective state, and fuel is supplied to a cylinder;
when the engine needs a two-stroke braking mode to operate, the first shaft sleeve (201) is at the second position, the second shaft sleeve (202) is at the second position, the braking rocker arm is in an effective state, and fuel is not supplied to the cylinder;
when the engine needs to operate in a two-stroke emergency braking mode, the first shaft sleeve (201) is located at the second position, the second shaft sleeve (202) is located at the second position, the braking rocker arm is in an effective state, and fuel is supplied into the cylinder.
6. The method of controlling a multi-mode valve train according to claim 5, wherein: for a multi-cylinder machine, a cylinder deactivation mode is adopted by a non-working cylinder, and a driving mode or a braking mode is adopted by a working cylinder.
7. The method of controlling a multi-mode valve train according to claim 5, wherein: for a multi-cylinder machine, in the braking mode, the cylinders adopt the same or different braking modes.
CN201910004412.5A 2018-12-11 2019-01-03 Multi-mode valve mechanism and control method thereof Expired - Fee Related CN109458238B (en)

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US7481185B1 (en) * 2007-08-14 2009-01-27 Robert Bosch Gmbh Multi-mode 2-stroke/4-stroke internal combustion engine
US7974766B2 (en) * 2007-09-07 2011-07-05 GM Gobal Technology Operations LLC Valvetrain control systems with lift mode transitioning based engine synchronization timing and sensor based lift mode control
DE202015003059U1 (en) * 2015-04-25 2015-07-30 Tobias Klauß Valve gear for the switchable operation of an internal combustion engine in two- or four-stroke
CN107060941B (en) * 2017-06-07 2020-05-19 大连理工大学 Double-camshaft switch fulcrum type variable-mode valve driving system
CN107060940B (en) * 2017-06-07 2019-11-22 大连理工大学 A kind of multi-mode valve-driving system

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