CN112483271B - Engine and control method thereof - Google Patents

Engine and control method thereof Download PDF

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Publication number
CN112483271B
CN112483271B CN202011293113.7A CN202011293113A CN112483271B CN 112483271 B CN112483271 B CN 112483271B CN 202011293113 A CN202011293113 A CN 202011293113A CN 112483271 B CN112483271 B CN 112483271B
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Prior art keywords
combustion chamber
air inlet
valve
engine
exhaust
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CN202011293113.7A
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Chinese (zh)
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CN112483271A (en
Inventor
张擘
汪硕峰
齐洪峰
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CRRC Industry Institute Co Ltd
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CRRC Academy Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D37/00—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for
    • F02D37/02—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for one of the functions being ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D15/00—Varying compression ratio
    • F02D15/04—Varying compression ratio by alteration of volume of compression space without changing piston stroke
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P5/00—Advancing or retarding ignition; Control therefor
    • F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
    • F02P5/145—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions using electrical means
    • F02P5/15—Digital data processing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

The invention relates to the technical field of power devices, and provides an engine and a control method thereof, wherein the engine comprises a cylinder body and a piston, a combustion chamber is formed in the cylinder body, the piston is connected in the cylinder body in a sliding manner, an air inlet channel and an air exhaust channel communicated to the combustion chamber are arranged on the cylinder body, and the engine also comprises: the adjusting top cover is connected in the cylinder body in a sliding manner and is used for adjusting the compression ratio in a sliding manner; the spark plug type cylinder pressure sensor is used for collecting pressure information in the combustion chamber and igniting; the intake valve is used for controlling the opening and closing of the air inlet passage and the combustion chamber passage; the exhaust valve is used for controlling the opening and closing of the exhaust passage and the combustion chamber passage; and the control device is used for controlling and adjusting the position of the top cover, the operation of the intake valve and the exhaust valve and the ignition of the spark plug type cylinder pressure sensor according to the pressure information. The engine and the control method thereof can enable the actual compression ratio of the engine to meet the requirement of efficient combustion of the mixed gas in real time, and have the advantages of simple structure and stable operation.

Description

Engine and control method thereof
Technical Field
The invention relates to the technical field of power devices, in particular to an engine and a control method thereof.
Background
Compression ratio has an important influence on the thermal efficiency of the engine and the combustion process, performance and emissions. According to the principle of the engine, the compression ratio is improved, so that the theoretical thermal efficiency is increased, and the combustion process of the fuel is improved. Increasing the compression ratio also improves the thermodynamic conditions of the mixture on ignition at low load conditions, thereby promoting improved ignition stability. However, raising the compression ratio also causes abnormal combustion problems such as knocking and knocking due to an increase in the in-cylinder temperature and pressure at the start of combustion. Especially under high load conditions, raising the compression ratio even causes problems such as damage to the engine parts due to a sharp increase in mechanical and thermal loads generated by combustion of the engine. Therefore, for the engine running under the changeable working condition, the compression ratio of the engine can be changed along with the change of the load, so that the mixed gas under any working condition can obtain the optimal combustion process and the engine power capability on the premise of ensuring that the abnormal combustion problems such as deflagration, detonation and the like do not occur.
The traditional four-stroke engine is limited by the structure of the engine, a certain compression ratio is mostly determined in the factory, and the value is not changed any more in the operation process. In order to adjust the compression ratio of the engine during operation, the prior art mostly adopts a method of controlling the position of the bottom dead center of the piston through a multi-connecting rod system to control the displacement change of the piston, and adjusts the ratio of the total volume to the clearance volume in the cylinder to achieve the purpose of changing the compression ratio. However, with this solution, the operation of the engine faces two challenges: one is that the adoption of the multi-connecting rod, the crankshaft and the piston to match and change the position of the bottom dead center of the piston relates to the change of the operation rule of a rotary motion part, so that the inertia force generated in the motion of the rotary motion part needs to be balanced properly, and the complexity of the mechanism is further increased; on the other hand, the technology is limited by the structural characteristics of a multi-link mechanism, the continuous variable compression ratio is difficult to realize, only the selection of a certain compression ratio can be realized, and the continuous adjustment of the compression ratio under multiple working conditions is not facilitated.
Disclosure of Invention
The invention provides an engine and a control method thereof, which are used for solving the problems that the mechanism is complex and is not beneficial to realizing continuous adjustment of compression ratio under multiple working conditions in the prior art.
The invention provides an engine, comprising a cylinder body and a piston, wherein a combustion chamber is formed in the cylinder body, the piston is connected in the cylinder body in a sliding manner, an air inlet channel and an air outlet channel which are communicated with the combustion chamber are arranged on the cylinder body, and the engine also comprises:
the adjusting top cover is connected in the cylinder body in a sliding mode and used for adjusting the compression ratio in a sliding mode;
the spark plug type cylinder pressure sensor is used for acquiring pressure information in the combustion chamber and igniting;
an intake valve for controlling opening and closing of a passage between the intake passage and the combustion chamber;
the exhaust valve is used for controlling the opening and closing of a passage between the exhaust passage and the combustion chamber;
and the control device is used for controlling the position of the adjusting top cover, the operation of the intake valve and the exhaust valve and the ignition of the spark plug type cylinder pressure sensor according to the pressure information.
According to the engine provided by the invention, the control device comprises an electronic control unit, a sliding control valve, an air inlet control valve and an air exhaust control valve, wherein the electronic control unit is respectively and electrically connected with the spark plug type cylinder pressure sensor, the sliding control valve, the air inlet control valve and the air exhaust control valve, the sliding control valve is connected with the adjusting top cover, the air inlet control valve is connected with the air inlet valve, and the air exhaust control valve is connected with the exhaust valve.
According to the engine provided by the invention, the adjusting top cover is fixedly connected with a combustion chamber push rod, the combustion chamber push rod is connected with the cylinder body in a sliding manner, and the combustion chamber push rod is connected with the sliding control valve.
According to the engine provided by the invention, the adjusting top cover is provided with a first vent hole for communicating the air inlet channel with the combustion chamber and a second vent hole for communicating the air outlet channel with the combustion chamber;
the air inlet valve comprises an air inlet valve guide rod and an air inlet valve end plate, the air inlet valve guide rod is connected with the air inlet control valve, and the air inlet valve end plate is fixedly connected with one end of the air inlet valve guide rod;
the exhaust valve comprises an exhaust valve guide rod and an exhaust valve end plate, the exhaust valve guide rod is connected with the exhaust control valve, and the exhaust valve end plate is fixedly connected with one end of the exhaust valve guide rod.
According to the engine provided by the invention, the push rod of the combustion chamber is fixedly connected with a valve actuating mechanism seat, the valve actuating mechanism seat is positioned outside the cylinder body, and the air inlet control valve and the air outlet control valve are arranged on the valve actuating mechanism seat.
According to the engine provided by the invention, the adjusting top cover is fixedly provided with an inlet valve guide member, one end of the inlet valve guide member is connected to the first vent hole, and the other end of the inlet valve guide member is in sliding connection with the air inlet channel, and/or the adjusting top cover is fixedly provided with an exhaust valve guide member, one end of the exhaust valve guide member is connected to the second vent hole, and the other end of the exhaust valve guide member is in sliding connection with the exhaust channel.
According to the engine provided by the invention, a sealing slide rail connected with the inlet valve guide in a sliding and sealing mode is arranged in the air inlet channel and close to the outlet, and/or a sealing slide rail connected with the exhaust valve guide in a sliding and sealing mode is arranged in the exhaust channel and close to the inlet.
The present invention also provides a control method applied to the engine described in any one of the above, including the steps of:
obtaining the pressure value in the cylinder and the unit lift of the pressure value in the cylinder rotating along with the crankshaft;
and adjusting the volume, the compression ratio and the ignition time in the combustion chamber according to the in-cylinder pressure value and the unit lift amount.
According to a control method provided by the present invention, the adjusting of the volume, the compression ratio, and the ignition time in the combustion chamber according to the in-cylinder pressure value and the unit lift amount includes:
when the in-cylinder pressure value is smaller than the rated pressure value of the engine body and the unit lift is smaller than a first threshold value, the adjusting top cover is moved to adjust the volume and the compression ratio in the combustion chamber until the in-cylinder pressure value is smaller than the rated pressure value of the engine body and the unit lift is not smaller than the first threshold value;
and when the in-cylinder pressure value is not less than the rated pressure value of the engine body, or the unit lift is not less than a second threshold value, delaying the ignition time and adjusting the volume and the compression ratio in the combustion chamber in a mode of moving the adjusting top cover until the in-cylinder pressure value is less than the rated pressure value of the engine body, and the unit lift is less than the second threshold value.
According to a control method provided by the present invention, the control method further includes:
monitoring the displacement of the adjusting top cover;
obtaining the relative error between the displacement and the target displacement;
and when the relative error is larger than a third threshold value, the adjusting top cover is moved to a position where the volume of the combustion chamber is maximum.
The engine and the control method thereof provided by the invention realize real-time change of the compression ratio and the discharge capacity of the engine in the running process of the engine by adjusting the top cover, the inlet valve and the exhaust valve, determine the motion rule of the movable adjusting top cover by detecting the cylinder pressure by the spark plug type cylinder pressure sensor, ensure that the actual compression ratio in the combustion chamber of the engine can meet the requirement of high-efficiency combustion of mixed gas in real time, control the combustion rate by changing the ignition angle and the compression ratio when the pressure or the pressure rising rate in the cylinder is overhigh, reduce the mechanical load and the thermal load born by the engine, and achieve the purpose of protecting the structure of the engine body on the premise of improving the work-doing capability and the thermal efficiency of the engine. The engine provided by the invention controls the cylinder pressure through a simple and direct structure, avoids the complexity of a mechanism and increases the operation stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic diagram of an engine configuration provided by the engine and control method of the present invention.
Reference numerals:
1: a cylinder body; 2: an air inlet channel; 3: an air intake control valve;
4: a sliding control valve; 5: an exhaust control valve; 6: an exhaust passage;
7: a seal ring; 8: an electronic control unit; 9: lifting the slide rail;
10: a piston; 11: sealing the slide rail; 12: an intake valve end plate;
13: an intake valve guide rod; 14: a spark plug type cylinder pressure sensor; 15: adjusting the top cover;
16: an exhaust valve end plate; 17: an exhaust valve guide rod; 18: a combustion chamber pushrod;
19: a valve train seat; 20: a vent hole; 21: an intake valve guide;
22: an exhaust valve guide; a-d: a control signal; e. f: a feedback signal.
Detailed Description
Embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.
In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.
An engine according to an embodiment of the present invention is described below with reference to fig. 1, the engine including: the device comprises a cylinder body 1, a piston 10, an adjusting top cover 15, a spark plug type cylinder pressure sensor 14, an inlet valve, an exhaust valve and a control device.
A combustion chamber is formed in the cylinder 1, and the piston 10 is slidably connected in the cylinder 1 so as to be capable of reciprocating in the axial direction of the cylinder 1. An air inlet channel 2 and an air outlet channel 6 which are communicated with the combustion chamber are arranged on the cylinder body 1, and tail gas generated after mixed gas entering the combustion chamber from the air inlet channel 2 is combusted can be discharged from the air outlet channel 6.
The adjusting top cover 15 is slidably connected in the cylinder body 1, and a sealing ring 7 is arranged on the adjusting top cover 15 to realize the sliding sealing between the adjusting top cover 15 and the cylinder body 1. After the adjusting top cover 15 is installed, the volume of the combustion chamber in the cylinder body 1 is actually a cavity enclosed by the adjusting top cover 15, the side close to the piston 10, and the inner wall of the cylinder body 1. The adjustment cap 15 can change the volume of the combustion chamber when sliding in the axial direction of the cylinder 1, and thus change the compression ratio when the piston 10 moves. The cylinder body 1 is provided with a vent hole 20, and when the adjusting top cover 15 slides, air can enter and exit from the vent hole 20, so that the cylinder body 1 can slide smoothly.
Spark plug formula cylinder pressure sensor 14 and regulation top cap 15 fixed connection, its sense terminal is towards piston 10 one side, and spark plug formula cylinder pressure sensor 14 can gather the atmospheric pressure in the combustion chamber in real time to can realize the ignition function.
The intake valve can be used to control opening and closing of the passage of the intake passage 2 with the combustion chamber, and thus to control the flux of the mixture.
The exhaust valve can be used to control the opening and closing of the exhaust passage 6 and the combustion chamber passage, and thus to control the exhaust gas displacement.
The control device is arranged outside the cylinder body 1 and comprises an electronic control unit 8, a sliding control valve 4, an air inlet control valve 3 and an air exhaust control valve 5. The control device is used for controlling and regulating the position of the top cover 15, the operation of the intake valve and the exhaust valve and the ignition of the spark plug type cylinder pressure sensor 14 according to the pressure information.
The electronic control unit 8 is connected with the spark plug type cylinder pressure sensor 14 through a lead, the lead of the spark plug type cylinder pressure sensor 14 can be arranged in the vent hole 20, and the electronic control unit 8 can receive a feedback signal f of the in-cylinder pressure collected by the spark plug type cylinder pressure sensor 14 and can send a control signal c of ignition to the spark plug type cylinder pressure sensor 14.
In one embodiment of the present invention, the adjusting top cover 15 is fixedly connected with a combustion chamber push rod 18, the combustion chamber push rod 18 is slidably connected to the cylinder body 1 through the lifting slide rail 9, and the sliding direction of the combustion chamber push rod 18 is the same as the sliding direction of the adjusting top cover 15. One end of a combustion chamber push rod 18 is positioned in the cylinder body 1 and fixedly connected with one side of the adjusting top cover 15, which is far away from the piston 10, and the other end of the combustion chamber push rod 18 is positioned outside the cylinder body 1. The part of the combustion chamber push rod 18, which is positioned outside the cylinder body 1, is connected with the sliding control valve 4, and the sliding control valve 4 can control the combustion chamber push rod 18 to slide, so as to drive the adjusting top cover 15 to move, thereby achieving the purpose of adjusting the compression ratio.
The electronic control unit 8 is electrically connected with the sliding control valve 4 through a lead, the electronic control unit 8 sends a control signal b for displacing the combustion chamber push rod 18 to the sliding control valve 4 to control the displacement of the combustion chamber push rod 18, and meanwhile, the electronic control unit 8 can receive a feedback signal e of the position of the combustion chamber push rod 18 sent by the sliding control valve 4 to judge the actual position of the combustion chamber push rod 18 so as to complete closed-loop control of the position of the combustion chamber push rod 18.
In one embodiment of the present invention, the adjusting top cover 15 is provided with a first vent hole for communicating the air inlet 2 with the combustion chamber and a second vent hole for communicating the air outlet 6 with the combustion chamber, and the first vent hole and the second vent hole respectively penetrate through the adjusting top cover 15.
The air inlet valve comprises an air inlet valve guide rod 13 and an air inlet valve end plate 12, one end of the air inlet valve guide rod 13 is fixedly connected with the air inlet valve end plate 12, and the other end of the air inlet valve guide rod sequentially penetrates through a first vent hole, the air inlet channel 2 and the outer wall of the cylinder body 1. The inlet valve guide rod 13 is connected with the cylinder body 1 in a sliding way, and the inlet valve guide rod 13 is connected with the inlet control valve 3. The intake control valve 3 can control the movement of the intake valve guide 13 to control the opening and closing of the first vent hole. Specifically, when the intake control valve 3 controls the intake valve guide rod 13 to move upward so that the intake valve end plate 12 covers the port on the side of the first vent hole close to the piston 10, the passage from the intake passage 2 to the combustion chamber can be blocked, and when the intake control valve 3 controls the intake valve guide rod 13 to move downward so that the intake valve cover plate is separated from the port on the side of the first vent hole close to the piston 10, the passage from the intake passage 2 to the combustion chamber can be opened.
The exhaust valve comprises an exhaust valve guide rod 17 and an exhaust valve end plate 16, one end of the exhaust valve guide rod 17 is fixedly connected with the exhaust valve end plate 16, the other end of the exhaust valve guide rod 17 penetrates through the second vent hole, the exhaust passage 6 and the outer wall of the cylinder body 1 in sequence, the exhaust valve guide rod 17 is in sliding connection with the cylinder body 1, and the exhaust valve guide rod 17 is connected with the exhaust control valve 5. The exhaust control valve 5 can control the movement of the exhaust valve guide rod 17 to control the opening and closing of the second vent hole, and specifically, the exhaust control valve 5 can close the passage from the exhaust passage 6 to the combustion chamber when the exhaust valve guide rod 17 is controlled to move upward to make the exhaust valve end plate 16 cover the port of the second vent hole close to the piston 10, and can open the passage from the exhaust passage 6 to the combustion chamber when the exhaust control valve 5 controls the exhaust valve guide rod 17 to move downward to make the exhaust valve end plate 16 separate from the port of the second vent hole close to the piston 10.
The electronic control unit 8 is connected to the intake control valve 3 and the exhaust control valve 5 by wires, respectively, and the electronic control unit 8 controls the operation of the intake control valve 3 by sending a control signal a, thereby controlling the opening and closing of the passage of the intake port 2 to the combustion chamber. The electronic control unit 8 controls the operation of the exhaust control valve 5 by issuing a control signal d, thereby controlling the opening and closing of the passage of the exhaust passage 6 to the combustion chamber.
Preferably, the exhaust valve end plate 16 and/or the intake valve end plate 12 are provided with a conical surface structure with the diameter gradually decreasing from the end close to the piston 10 to the end away from the piston 10, so that a good sealing effect can be achieved.
Furthermore, the combustion chamber push rod 18 is fixedly connected with a valve actuating mechanism seat 19, and the valve actuating mechanism seat 19 is located outside the cylinder body 1 and is slidably connected with the cylinder body 1 through a lifting slide rail 9. The air inlet control valve 3 and the air exhaust control valve 5 are arranged on the valve mechanism seat 19, when the combustion chamber push rod 18 drives the adjusting top cover 15 to move, the air inlet control valve 3 and the air exhaust control valve 5 can be driven to move synchronously, and when the first vent hole and the second vent hole are opened and closed, the moving distance of the air inlet valve guide rod 13 and the air exhaust valve guide rod 17 is unchanged, and the adjustment is not required according to the position of the adjusting top cover 15.
In one embodiment of the present invention, an intake valve guide 21 is fixedly disposed on the adjusting top cover 15, one end of the intake valve guide 21 is connected to the first vent hole, and the other end is slidably connected to the intake passage 2, and/or an exhaust valve guide 22 is fixedly disposed on the adjusting top cover 15, one end of the exhaust valve guide 22 is connected to the second vent hole, and the other end is slidably connected to the exhaust passage 6. The intake valve guide 21 and the exhaust valve guide 22 are of a cylindrical structure, the intake valve guide 21 and the exhaust valve guide 22 can guide the adjusting top cover 15, and it can be ensured that the mixed gas in the intake passage 2 smoothly reaches the first vent hole and the tail gas of the second vent hole smoothly reaches the exhaust passage 6.
Furthermore, a sealing slide rail 11 connected with the inlet valve guide 21 in a sliding and sealing mode is arranged in the position, close to the outlet, of the air inlet channel 2, and/or a sealing slide rail 11 connected with the exhaust valve guide 22 in a sliding and sealing mode is arranged in the position, close to the inlet, of the air outlet channel 6, and the sealing slide rail 11 can be a cylindrical slide rail and can increase sliding stability.
According to the engine, the motion rule of the movable adjusting top cover 15 is determined by acquiring the cylinder pressure in the combustion chamber in real time through the spark plug type cylinder pressure sensor 14, so that the actual compression ratio in the combustion chamber of the engine can meet the requirement of efficient combustion of mixed gas in real time; and when the pressure in the cylinder or the pressure rise rate is too high, the combustion rate is controlled by changing the ignition angle and the compression ratio, the mechanical load and the thermal load born by the engine are reduced, and the purpose of protecting the engine body structure is achieved on the premise of improving the work capacity and the thermal efficiency of the engine. The moving process of the adjusting top cover 15 is a continuous adjusting process of the compression ratio, and requirements of different working conditions can be met.
In an embodiment of the present invention, there is also provided a control method of an engine, which can be applied to the engine in any one of the above embodiments. The control method of the engine includes the steps of:
s100, obtaining the pressure value in the cylinder and the unit lift of the pressure value in the cylinder along with the rotation of the crankshaft.
The electronic control unit 8 obtains the in-cylinder pressure by receiving the feedback signal f from the spark plug type cylinder pressure sensor 14, and further calculates a unit rise amount (a pressure rise value per crank angle) of the in-cylinder pressure value with the rotation of the crankshaft from the in-cylinder pressure.
And S200, adjusting the volume, the compression ratio and the ignition time in the combustion chamber according to the in-cylinder pressure value and the unit lift amount.
Step S200 specifically includes:
s201, when the in-cylinder pressure value is smaller than the rated pressure value of the engine body and the unit lift is smaller than a first threshold value, the adjusting top cover 15 is moved to adjust the volume and the compression ratio in the combustion chamber until the in-cylinder pressure value is smaller than the rated pressure value of the engine body and the unit lift is not smaller than the first threshold value.
Specifically, the first threshold may be 0.1MPa, and when the in-cylinder pressure is less than the rated pressure of the engine body and the unit lift is less than 0.1MPa, the electronic control unit 8 sends the control signal b to make the sliding control valve 4 control the combustion chamber push rod 18 to move downward, and the combustion chamber push rod 18 drives the adjusting top cover 15 to move downward, so as to reduce the volume of the combustion chamber, and further increase the compression ratio of the engine. And when the unit lift increases to 0.2MPa, the electronic control unit 8 sends out a control signal b to enable the sliding control valve 4 to control the position of the push rod 18 of the combustion chamber to be kept unchanged.
S202, when the pressure value in the cylinder is not less than the rated pressure value of the engine body, or the unit lift is not less than a second threshold value, the ignition time is delayed and the adjusting top cover 15 is moved to adjust the combustion gravity center, the volume in the combustion chamber and the compression ratio until the pressure value in the cylinder is less than the rated pressure value of the engine body, and the unit lift is less than the second threshold value.
Specifically, the second threshold may be 0.3MPa, and when the in-cylinder pressure is greater than or equal to the rated pressure value, or the unit lift amount is greater than or equal to 0.3MPa, the electronic control unit 8 first controls the ignition timing of the spark plug type cylinder pressure sensor 14 to be retarded by 5 crank angle degrees by sending the ignition signal c. And judging whether the pressure in the cylinder is still greater than or equal to the rated pressure value or whether the unit lift is still greater than or equal to 0.3MPa or not through the feedback signal f. And if the pressure in the cylinder is smaller than the rated pressure value or the unit lift is smaller than 0.3MPa, maintaining the current state. If the pressure in the cylinder is still greater than or equal to the rated pressure value or the unit lift is still greater than or equal to 0.3MPa, the sliding control valve 4 controls the push rod 18 of the combustion chamber to move upwards by sending a control signal b. At this time, the combustion chamber push rod 18 drives the adjusting top cover 15 to move upwards, so that the volume of the combustion chamber is increased, and further the compression ratio in the combustion chamber is reduced. And when the unit lift is reduced to 0.2MPa and the pressure in the cylinder is smaller than the rated pressure value, the electronic control unit 8 sends out a control signal b to enable the sliding control valve 4 to control the position of the push rod 18 of the combustion chamber to be kept unchanged.
In one embodiment of the present invention, the control method further includes:
s300, monitoring the displacement of the adjusting top cover 15, obtaining the relative error between the displacement and the target displacement, and when the relative error is larger than a third threshold value, moving the adjusting top cover 15 to the position where the volume of the combustion chamber is maximum.
Specifically, the third threshold value is 10%, during the process that the electronic control unit 8 sends the control signal b to enable the sliding control valve 4 to control the combustion chamber push rod 18 to move, the feedback signal e related to the position of the combustion chamber push rod 18 is received from the sliding control valve 4, the relative error between the displacement and the target displacement is obtained through the feedback signal e, when the relative error is larger than 10%, the electronic control unit 8 judges that the system is in failure, the control signal b is sent immediately to enable the sliding control valve 4 to control the combustion chamber push rod 18 to move to the uppermost position, and therefore the adjusting top cover 15 is moved to the position where the volume of the combustion chamber is the largest, and the running safety of the engine is guaranteed.
It should be noted that step S300 can be applied to both execution modes of step S201 and step S202, so as to achieve the purpose of ensuring the safety of engine operation.
The following experiments were performed for various operating conditions in one embodiment of the invention:
experimental engine the engine is shown in figure 1. During the experiment, the crankshaft of the engine is connected with a dynamometer, the rotating speed of the engine is stabilized at 2000r/min through the dynamometer, the oil consumption of the engine is measured through an oil consumption meter installed on an experiment bench, the thermal efficiency of the engine is further calculated, and the data of the cylinder pressure and the pressure rise rate are read through communication calibration software of the electronic control unit 8. The engine used in the experiment is a natural air suction type engine with certain discharge capacity of 1.6L, the maximum design bearing pressure of a combustion chamber is 10MPa, and the minimum compression ratio generated when the movable combustion chamber top cover 15 is arranged at the top is 10.1. The following experiments were performed on this test system:
(1) Compression ratio increase experiment:
the engine was operated at 2000r/min with an effective torque of 40 Nm. The electronic control unit 8 obtains the maximum value of the in-cylinder pressure of 4.39MPa and the maximum pressure rise rate of 0.041 MPa/degree crank angle by receiving the feedback signal f from the spark plug type cylinder pressure sensor 14. According to the signals, the electronic control unit 8 sends a control signal b of the position of the push rod 18 of the combustion chamber to control the sliding control valve 4 to drive the push rod 18 of the combustion chamber to drive the valve train seat 19 to synchronously move downwards together with the sliding combustion chamber top cover 15, so that the compression ratio in the combustion chamber is increased. When the compression ratio is increased to 11.6, the electronic control unit 8 detects that the rate of increase in the in-cylinder pressure reaches 0.22MPa/° crank angle. At this time, the electronic control unit 8 enables the position of the combustion chamber push rod 18 controlled by the sliding control valve 4 to be kept unchanged by sending a control signal b of the position of the combustion chamber push rod 18, and the engine keeps running at the compression ratio of 11.6.
The test result shows that the effective thermal efficiency of the engine is 27.4% before the compression ratio is changed, when the compression ratio is increased to 11.6 by the device and the strategy provided by the invention, the effective thermal efficiency of the engine is increased to 30.6%, and the thermal efficiency is relatively increased by 11.7%.
(2) Compression ratio adjustment experiment:
under the working condition of 2000r/min and 100Nm of the engine, the combustion intensity is rapidly improved by increasing the fuel concentration. At this time, the electronic control unit 8 receives the feedback signal f from the spark plug type cylinder pressure sensor 14 to obtain a maximum value of the in-cylinder pressure of 8.82MPa and a maximum pressure rise rate of 0.53 MPa/degree of crank angle. Based on the above signals, the electronic control unit 8 delays the ignition timing of the spark plug type cylinder pressure sensor 14 by 5 crank angle degrees by issuing the control signal c. After the ignition angle is delayed by 5 degrees of crank angle, the electronic control unit 8 calculates the maximum pressure rise rate to be 0.46 MPa/degree of crank angle according to the cylinder pressure signal f, the electronic control unit 8 judges that the compression ratio should be reduced at the moment, and the electronic control unit 8 controls the sliding control valve 4 to drive the combustion chamber push rod 18 to drive the valve mechanism seat 19 to synchronously move upwards together with the sliding combustion chamber top cover 15 by sending out a control signal b of the position of the combustion chamber push rod 8, so that the compression ratio of the engine starts to be reduced from 11.1 at the beginning of the experiment. When the compression ratio is reduced to 10.5, the electronic control unit 8 detects that the maximum pressure increase rate is 0.2MPa/° crank angle. At this time, the electronic control unit 8 makes the position of the push rod 18 of the combustion chamber controlled by the sliding control valve 4 keep unchanged by sending out a control signal b of the position of the push rod 18 of the combustion chamber, the engine knocking is eliminated, and the thermal efficiency is improved to 31.2 percent from 28.8 percent before the compression ratio is reduced.
The experimental results show that the engine provided by the invention can control the compression ratio of the engine in real time according to the cylinder pressure information under different engine working conditions, the thermal efficiency of the engine can be increased by improving the compression ratio under a low-load working condition, and the detonation phenomenon can be eliminated by adjusting the ignition angle and the compression ratio under the conditions of overhigh mechanical load and detonation of the engine, so that the high-efficiency and stable operation of the engine is realized.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (2)

1. An engine, includes cylinder body and piston, form the combustion chamber in the cylinder body, piston sliding connection be in the cylinder body, be provided with on the cylinder body and communicate to the intake duct and the exhaust passage of combustion chamber, its characterized in that, the engine still includes:
the adjusting top cover is connected in the cylinder body in a sliding mode and used for adjusting the compression ratio in a sliding mode, and a sealing ring is arranged on the adjusting top cover to achieve sliding sealing between the adjusting top cover and the cylinder body; the adjusting top cover is fixedly connected with a combustion chamber push rod, the combustion chamber push rod is connected to the cylinder body in a sliding mode, and a first vent hole for communicating the air inlet channel with the combustion chamber and a second vent hole for communicating the air outlet channel with the combustion chamber are formed in the adjusting top cover; the combustion chamber push rod is fixedly connected with a valve actuating mechanism seat, and the valve actuating mechanism seat is positioned outside the cylinder body; an air inlet valve guide piece is fixedly arranged on the adjusting top cover, one end of the air inlet valve guide piece is connected to the first air vent, and the other end of the air inlet valve guide piece is in sliding connection with the air inlet channel;
the spark plug type cylinder pressure sensor is used for acquiring pressure information in the combustion chamber and igniting;
an intake valve for controlling opening and closing of a passage between the intake passage and the combustion chamber;
an exhaust valve for controlling opening and closing of a passage between the exhaust passage and the combustion chamber;
control means for controlling the position of said regulator cap, the operation of said intake and exhaust valves and the ignition of said spark plug cylinder pressure sensor in accordance with said pressure information;
the control device comprises an electronic control unit, a sliding control valve, an air inlet control valve and an exhaust control valve, wherein the electronic control unit is respectively and electrically connected with the spark plug type cylinder pressure sensor, the sliding control valve, the air inlet control valve and the exhaust control valve;
the combustion chamber push rod is connected with the sliding control valve;
the air inlet valve comprises an air inlet valve guide rod and an air inlet valve end plate, the air inlet valve guide rod is connected with the air inlet control valve, and the air inlet valve end plate is fixedly connected with one end of the air inlet valve guide rod;
the exhaust valve comprises an exhaust valve guide rod and an exhaust valve end plate, the exhaust valve guide rod is connected with the exhaust control valve, and the exhaust valve end plate is fixedly connected with one end of the exhaust valve guide rod;
the air inlet control valve and the air exhaust control valve are arranged on the valve mechanism seat;
and a sealing slide rail connected with the inlet valve guide in a sliding and sealing manner is arranged at a position close to the outlet in the air inlet channel, and/or a sealing slide rail connected with the exhaust valve guide in a sliding and sealing manner is arranged at a position close to the inlet in the air outlet channel.
2. A control method applied to an engine according to claim 1, characterized by comprising the steps of:
obtaining an in-cylinder pressure value and a unit lift of the in-cylinder pressure value rotating along with the crankshaft;
adjusting the volume, the compression ratio and the ignition time in the combustion chamber according to the in-cylinder pressure value and the unit lift;
the adjusting of the volume, the compression ratio, and the ignition time in the combustion chamber according to the in-cylinder pressure value and the unit lift amount includes:
when the in-cylinder pressure value is smaller than a rated pressure value of an engine body and the unit lift is smaller than a first threshold value, moving the adjusting top cover to adjust the volume and the compression ratio in the combustion chamber until the in-cylinder pressure value is smaller than the rated pressure value of the engine body and the unit lift is not smaller than the first threshold value;
when the in-cylinder pressure value is not smaller than the rated pressure value of the engine body, or the unit lift is not smaller than a second threshold value, delaying ignition time and adjusting the volume and the compression ratio in the combustion chamber in a mode of moving the adjusting top cover until the in-cylinder pressure value is smaller than the rated pressure value of the engine body, and the unit lift is smaller than the second threshold value;
the control method further comprises the following steps:
and monitoring the displacement of the adjusting top cover, obtaining the relative error between the displacement and the target displacement, and moving the adjusting top cover to the position with the maximum volume of the combustion chamber when the relative error is greater than a third threshold value.
CN202011293113.7A 2020-11-18 2020-11-18 Engine and control method thereof Active CN112483271B (en)

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US8631782B2 (en) * 2008-08-22 2014-01-21 GM Global Technology Operations LLC Active compression ratio modulation through intake valve phasing and knock sensor feedback
US8781710B2 (en) * 2011-05-10 2014-07-15 GM Global Technology Operations LLC Compression ratio determination and control systems and methods
CN102735395A (en) * 2012-06-21 2012-10-17 天津大学 On-line diagnosis and control method for knockings of internal-combustion engine
ES2531587B1 (en) * 2013-07-02 2015-11-12 Benoit Laurent PHILIPPE Internal combustion engine
CN104454180A (en) * 2014-09-30 2015-03-25 董伟冈 Internal combustion engine power device, engine and running methods of internal combustion engine power device
CN105257422A (en) * 2015-09-24 2016-01-20 宁波星豪汽车维修有限公司 Cylinder cover system capable of adjusting compression ratio for engine and internal combustion engine with cylinder cover system
CN204984614U (en) * 2015-09-24 2016-01-20 宁波星豪汽车维修有限公司 Engine intake piston compression ratio governing system

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