240 results about "Top dead center" patented technology

A powered fastener driver including a piston movable within an inner cylinder from a top-dead-center (TDC) position to a driven or bottom-dead-center (BDC) position. The piston has a reduced stroke length between the TDC position and the BDC position.

A sliding arrangement for use in an internal combustion engine is described, comprising a cylinder liner (1) and at least one piston ring (10), wherein the liner (1) has a through-bore defining an inner surface (S) which in turn defines three sections: a first section (2) near the end of the piston stroke, facing the cylinder head (at top dead center, TDC); a second, middle section (3); and a third section (4) near the end of the piston stroke, facing the crankshaft of the engine (at top dead center, TDC), wherein (i) the TDC section (2) of the liner (1) has a surface finish with a first roughness value defined by a structure of recesses and projections (“valleys” and “raised areas”); the middle section (3) of the liner (1) has a surface finish with a second roughness value defined by a structure of recesses and projections (“valleys” and “raised areas”);(1) the BDC section (4) of the cylinder liner (1) has a surface finish with a third roughness value defined by a structure of recesses and projections (“valleys” and “raised areas”), and the roughness value of the middle section (3) is significantly lower than the roughness value of the TDC section (2), and is defined by an essentially very smooth structure of recesses and projections (“valleys” and “raised areas”); and (ii) a ceramic coating (R) is applied to at least part of the contact surface of the piston ring (10) by the physical vapor deposition (PVD) process.

A sewing machine has a throat plate (3a) and a material hold-down foot (13) for performing a lifting movement to hold down the material on the throat plate (3a) during a sewing operation. A driven stroke amplitude adjusting device (17) serves to adjust a stroke amplitude of the lifting movement of the material hold-down foot between a top dead center and a bottom dead center. A driven stroke level adjusting device serves to adjust a stroke level of the lifting movement of the material hold-down foot (13) relative to the throat plate (3a). A control / regulating device (11) is in signal communication with the stroke amplitude adjusting device (17) and with the stroke level adjusting device. Operating methods that are possible with the sewing machine are also specified. The result is a sewing machine with which sewing material of different thicknesses and / or different numbers of layers can be sewn precisely and flexibly.

A powered fastener driver including a housing defining a cylinder support portion, a drive unit support portion, and a handle portion that is spaced apart from the drive unit support portion. The powered fastener driver includes a cylinder, a piston movable within the cylinder from a top-dead-center (TDC) position to a bottom-dead-center (BDC) position, a driver blade attached to the piston for movement therewith along a driving axis from the TDC position toward the BDC position, a lifter operable to move the piston and driver blade, in unison, from the BDC position toward the TDC position, and a drive unit supported by the drive unit support portion and operably coupled to the lifter. The powered fastener driver further includes a user interface supported by the housing, and a printed circuit board positioned within the housing and positioned between the drive unit support portion and the handle portion.

A powered fastener driver including: a rotary lifter rotatably supported within the housing and configured to sequentially engage the plurality of teeth to move a driver blade from a bottom-dead-center position toward a top-dead-center position; a drive unit configured to provide torque to the rotary lifter, causing it to rotate; a nosepiece defining a fastener driving channel, the fastener driving channel extending along a driving axis of the driver blade; a workpiece contact element movable relative to the nosepiece between an extended position and a retracted position; a sensor assembly including a first inductive sensor configured to detect a position of the workpiece contact element in one of the extended position or the retracted position; and a second inductive sensor configured to detect an angular position of the rotary lifter, wherein the first inductive sensor and the second inductive sensor are on opposite sides of the rotary lifter.

The disclosure is directed to an ignition circuit for a combustion engine. The combustion engine has a piston movable between a top dead center and a bottom dead center and, via a connecting rod, drives a crankshaft. Combustion air is apportioned via an intake channel. A control circuit provides an ignition time for the idling situation and an ignition time for the acceleration situation. To adjust an early switch to an ignition time for the acceleration situation, provision is made to monitor the rotational speed of the crankshaft over a crankshaft angle range and to detect the value of a drop in rotational speed. The value of the detected drop in rotational speed is compared to a predetermined value of a drop in rotational speed and, when the predetermined value of the drop in rotational speed is exceeded, a switch is made to the ignition time for the acceleration situation.

The invention provides a control method of a dual-fuel methanol-diesel dual direct injection engine and a vehicle, and the method comprises the following steps: determining the temperature working condition of the vehicle according to the environment temperature of the vehicle; under the extremely cold working condition, a diesel oil nozzle is controlled to inject diesel oil according to the first-time pre-injection, the second-time pre-injection, the third-time pre-injection and the main injection of each cycle, in the successive injection process, the corresponding angle of a crank angle in front of a compression top dead center is gradually reduced, and the injection amount is gradually increased; under the cold working condition, a diesel oil nozzle is controlled to inject diesel oil according to injection parameters corresponding to second-time pre-injection, third-time pre-injection and main injection; under the normal-temperature working condition, a diesel oil nozzle is controlled to inject diesel oil according to injection parameters corresponding to third-time pre-injection and main injection; and under the high-temperature working condition, a dual-fuel mode is directly entered, the diesel nozzle is controlled to inject diesel, and the methanol nozzle is controlled to inject methanol. Through the control method provided by the invention, the problem of poor cold starting performance caused by adopting a single diesel injection rate in the cold starting stage is solved.

The invention provides a two-stroke piston engine integrated controller with high-reliability position estimation, which is characterized in that a motor Hall signal acquisition function is added on the basis of an engine crankshaft position signal acquisition circuit of a conventional engine control module. A crankshaft position signal redundancy switching logic of the two-stroke piston engine is designed based on an improved circuit, a groove pole position behind a top dead center is positioned in the operation process of the engine, synchronous correction of a Hall signal and a crankshaft position signal is achieved, and a conversion relation between a motor Hall signal and the crankshaft position signal of the engine is established. When the crankshaft position signal is abnormal, the engine timing control method based on the motor Hall signal can be automatically switched. According to the invention, the redundancy switching of the position signal of the two-stroke piston engine can be realized, so that the piston engine can still complete a set task without flameout when the crankshaft position signal is abnormal, and the reliability of a control system is greatly improved.

A vaned hydraulic pump / hydraulic motor has a housing (1) and an impeller (2) which has vanes (3) rigidly fastened thereto or which is provided in the form of a single one-piece part. Situated between the vanes (3), in the body of the impeller (2), are radial channels (4) with reciprocally movable pistons (5) disposed therein. The pistons (5) are movably fastened via rods (6) to a common hub (7), and the axis of rotation of the hub (7) is radially offset from the axis of rotation of the impeller (2). The hub (7) is coupled to the impeller (2) by a universal joint (10) such as to be capable of rotating together with and at the same speed as the impeller. In the body of each piston (5) there is a cavity (5a) which is capable of receiving a hydraulic fluid and which has a compressible element (5b) mounted therein that is variable in volume under the influence of excess pressure arising as the piston (5) passes through top and bottom dead centre.

An apparatus and method for operating an engine. The apparatus includes a crankshaft trigger wheel coupled to a crankshaft and a set of sensors equipped to generate a crankshaft signal associated with an instantaneous speed of the crankshaft trigger wheel. A controller is configured to receive the crankshaft signal corresponding to the instantaneous speed, determine a minimum instantaneous speed for the crankshaft trigger wheel to overcome a top dead center (TDC), and predict a reverse rotation event for the engine when the instantaneous speed falls below the minimum instantaneous speed. After making the prediction, ignition of the engine is prevented prior to the reverse rotation event occurring.

A powered fastener driver and a driver system, the powered fastener driver including a driver blade movable from a top dead center position to a bottom dead center position for driving a fastener into a workpiece. The driver may include a lift assembly for providing a torque to move the driver blade from a bottom dead center position toward a top dead center position, the lift assembly including a rotary lift configured to be selectively engageable with the driver blade, the rotary lift having a plurality of lift pins and a roller disposed on at least one of the lift pins, wherein the roller comprises a plurality of cam portions defined by a cup-shaped recess having a first radius oriented parallel to the direction of rotation of the roller and a second radius perpendicular to the first radius, and wherein the driver blade comprises a lifting tooth having a crown disposed thereon, the crown portion is configured to engage with at least one of the plurality of cam portions.

A powered fastener driver includes a driver blade, a lifter, a nose piece, a magazine, and a light. The driver blade is configured to be movable between a top-dead center position and a bottom-dead center position. The lifter is operable to move the driver blade from the bottom-dead center position toward the top-dead center position. The drier blade is extendable through the nose piece when moving from the top-dead center position to the bottom-dead center position. The magazine is configured to transfer individual fasteners into the nose piece. The magazine has a front side configured to face the workpiece during driving of the fastener, an opposite rear side, and a lateral side extending between the front side and the rear side. The light is positioned adjacent the lateral side of the magazine closer to the front side than the rear side.

A stand for a portable band saw, to which a portable band saw is attached, comprises a base, a mounting arm which is pivotally mounted about a pivot point through the base and to which the portable band saw is attached, and a return device configured to automatically return the mounting arm to a top dead center.

The application provides a methanol engine with an internal direct injection structure applied to the field of methanol engines, wherein the valve is directly installed in the interior of the cylinder, the methanol fuel can be directly atomized and injected in the interior of the cylinder, loss caused by injection of the methanol fuel in the intake pipe can be avoided, the first fuel injection is performed when the piston moves from the top dead center to 1 / 2 of the total stroke, the second fuel injection is performed when the piston moves to the bottom dead center position, the two fuel injections are performed in stages, the mixing effect of the two fuel injections can be enhanced by the disturbance of the air flow in the cylinder, the methanol fuel combustion efficiency is improved to a certain extent, fuel loss in the starting process of the methanol engine is reduced, the methanol fuel is fully combusted, the working efficiency is effectively improved, and the methanol engine is more economical and environmentally friendly.

Internal combustion engine control device (100) comprising a control unit that controls the operating conditions of an internal combustion engine (1) using a pulse output from a crank angle sensor (101) which detects a rotational state of a crankshaft (6) of the internal combustion engine (1) by detecting a plurality of convex teeth (7b) arranged in a radial direction on an outer periphery of a body part (7a) designed as a circular plate element of a pulse generator wheel (7, 7', 7") connected to the crankshaft (6), characterized in that the plurality of convex teeth (7b) has a plurality of short convex teeth (7b1) and a plurality of long convex teeth (7b2), each having circumferential lengths (B2) that are longer than the respective circumferential lengths (B1) of the body part (7a) at the short convex teeth (7b1), wherein the plurality of long convex teeth (7b2) is provided in a first arrangement area over a retard-side angular range of 90 degrees from a top dead center angular position (TDC) of the internal combustion engine (1) on a retard side, and over a lead-side angular range of 90 degrees from the top dead center angular position (TDC) on a lead-side, wherein in a predetermined positional mounting relation of the pulse generator wheel (7, 7', 7") the plurality of short convex teeth (7b1) is provided in a second arrangement area which, in the predetermined positional mounting relation, lies outside the first arrangement area, the control unit detects a rising edge of the pulse output or a falling edge of the pulse output, which is generated successively in time sequence, in accordance with the fact that the crank angle sensor (101) detects circumferential ends (7b11, 7b12, 7b21, 7b22) of a convex tooth from the plurality of short convex teeth (7b1) and the plurality of long convex teeth (7b2), an arithmetic processing operation performed by the control unit, comprising a first cranking process, which is an arithmetic processing operation performed upon detection of a pulse end by the control unit, which is one of the rising and falling edges of the pulse output generated in accordance with the crank angle sensor (101) detecting an end of a tooth that is one of the circumferential ends (7b11, 7b12, 7b21, 7b22) of the plurality of short convex teeth (7b1) and the plurality of long convex teeth (7b2), and a second cranking process, which is an arithmetic processing operation performed upon detection of the other pulse end by the control unit, which is the other of the rising and falling edges of the pulse output generated in accordance with the crank angle sensor (101) detecting another end of the tooth that is the other of the circumferential ends (7b21,7b22) from the multitude of long convex teeth (7b2).

Internal combustion engine method, comprising: operating an engine in a first mode, the first mode comprising: Confirming the cold start condition of the engine, determining that the boiling point of the fuel in the engine is lower than a threshold boiling point of the fuel, and In response to confirmation of the engine's cold-start condition and determination that the fuel boiling point in the engine is lower than a threshold fuel boiling point, starting the internal combustion engine via a starter motor at an initial cranking speed, while fuel is injected via fuel injectors for a number of combustion engine cycles since the first combustion engine cycle, and subsequently suspending operation of the starter motor and operating the engine via combustion; and Operating the engine in a second mode, the second mode comprising the following: In response to confirmation of the engine's cold-start condition and determination that the fuel boiling point in the engine is higher than a threshold fuel boiling point, the internal combustion engine is started at a second cranking speed while fuel is injected and the ignition spark is deactivated for the number of combustion engine cycles since the first combustion engine cycle, and subsequently the operation of the starter motor is suspended and the engine is operated via combustion, wherein the fuel boiling point is based on a fuel composition in the engine, wherein in the first mode the fuel injection involves initiating fuel supply at top dead center (TDC) of an intake stroke of a combustion engine cycle and terminating fuel supply at bottom dead center (BDC) of the intake stroke of the combustion engine cycle.and wherein, in the second mode, fuel injection includes initiating fuel supply at TDC of the intake stroke of the internal combustion engine cycle and terminating fuel supply at TDC of a compression stroke of the internal combustion engine cycle.

A rotor engine comprehensive bench test system and test method belong to the technical field of engine test. The system contains rotor engine, AC power dynamometer, main control unit and other groups of modules. The dynamometer can realize forward and reverse reversible rotation of the engine. The main control unit is provided with forward and reverse switching and three-stage alarm module. Each component is connected and communicated. Sensors, acquisition modules, analyzers and the main control unit are cooperatively networked. The test method sequentially completes bench building, system inspection, pre-starting verification, lubrication establishment, engine starting, top dead center searching, mechanical loss test, warming, full-range boundary monitoring, hot-state running-in, ECU online calibration and data evaluation. The combustion analyzer can calculate cylinder pressure parameters. ECU modified parameters take effect immediately. Data analysis covers power and economic indicators. The present invention solves the problem that existing benches cannot adapt to rotor engine tests, builds a safe and efficient comprehensive test platform and provides technical support for rotor engine research and development.

The application discloses a method and device for self-learning control of upper and lower dead point positions of a throttle valve, which comprises the following steps: driving a valve plate to a lower dead point position of the throttle valve, recording the minimum position of the valve plate, driving the valve plate to an upper dead point position of the throttle valve, and recording the maximum position of the valve plate; recording a first overshoot amount of the valve plate at the moment when the valve plate runs from the minimum position to the maximum position, and recording a second overshoot amount of the valve plate at the moment when the valve plate runs from the maximum position to the minimum position; based on the interval range from the minimum position to the maximum position, a plurality of test overshoot amount positions are set, and a plurality of test overshoot amounts generated when the valve plate runs at the plurality of test overshoot amount positions are recorded; the maximum value is selected from the first overshoot amount, the second overshoot amount and the plurality of test overshoot amounts, and based on the maximum value, the minimum position and the maximum position, the self-learned lower dead point position and the upper dead point position are obtained. The control method can effectively reduce the risk of impact on the mechanical upper and lower dead point positions.

A powered fastener driver includes a driver blade movable from a top-dead-center (TDC) position to a bottom-dead-center (BDC) position, and a drive unit providing torque to move the driver blade, the drive unit having an output shaft defining a rotational axis. The driver further includes a rotary lifter engageable with the driver blade and receives torque from the drive unit in a rotational direction for returning the driver blade from the BDC position toward the TDC position, an aperture defined within the lifter through which the output shaft extends permitting radial movement of the lifter relative to the output shaft between a first position and a second position, and a spring biasing the lifter to the first position. The lifter translates in a radial direction relative to the output shaft from the first position toward the second position from engagement with the driver blade while rotating in the rotational direction.

A device to level a metal plate fabricated from a material includes a frame, a leveling station, and a draw device. The leveling station includes a single upper roller and a pair of lower rollers in parallel arrangement and defining a serpentine path. A plunge depth is defined based upon a difference between a top-dead-center point of the lower rollers and a bottom-dead-center point of the single upper roller. A longitudinal spacing and the plunge depth are configured such that the single upper roller and the lower rollers are disposed to impart a bend radius on the metal plate as the metal plate is drawn or moved through the serpentine path such that the metal plate has line contact with the outer peripheral surfaces of the single upper roller and the lower rollers. The bend radius is selected to achieve plastification of the metal sheet.

The invention discloses an engine lubricating oil circuit and an engine, and relates to the technical field of motorcycle engines, the engine lubricating oil circuit comprises a shell, a crankshaft chamber is arranged in the shell, and an air cylinder is arranged on the crankshaft chamber; the piston is arranged on the air cylinder and can move between an upper dead center and a lower dead center along the inner wall of the air cylinder; the crank connecting rod assembly is connected with the piston and used for driving the piston to reciprocate in the air cylinder; the oil spraying nozzle is arranged in the shell and located between the crank connecting rod assembly and the piston, and the oil spraying nozzle communicates with the oil supply assembly and is used for spraying one to four spraying oil beams to the piston; and the cooling engine oil collecting structure is arranged at the bottom of the crankshaft cavity in the shell and located on the inner walls of the two sides of the crankshaft cavity, and the cooling engine oil collecting structure is used for recycling engine oil. According to the engine lubricating oil way and the engine, at least one injection oil beam is emitted to the piston, the oil beam can be collected through the cooling engine oil collecting structure so as to be recycled, and the engine oil utilization rate is increased.

Engine starting system with: a starting device (2, 3) for transmitting an associated rotational force to a crankshaft (1a) of a power engine (1) in order to drive the crankshaft (1a); and a control device (4) for controlling the operation of the starting device (2, 3) in response to a start request from the power machine (1); where the engine starting system includes a rotation determination section (11) which is able to distinguish a direction of rotation of the crankshaft (1a); where a period of time during which the crankshaft (1a) rotates in a reverse direction while the engine (1) is stopped is referred to as a reverse rotation period, the control device (4) sets a reverse rotation period as a crank-start prevention period to prevent the starting device (2, 3) from driving the crankshaft (1a); and if the start request is generated during a reverse rotation period, the start device (2, 3) is operated on the basis of information from the rotation determination section (11) to drive the crankshaft (1a) when it is detected that the crankshaft (1a) has switched from a reverse rotation to a forward rotation, characterized by the fact that the starting device (2, 3) comprises a first starting device (2) which is permanently connected to the crankshaft (1a), and a second starting device (3) which has a coupling function which is able to be connected to the crankshaft (1a); and, if the start request is generated during a reverse rotation period, the control device (4) drives the crankshaft (1a) through one of the first start device (2) and the second start device (3) or both the first start device (2) and the second start device (2), wherein the control device (4) operates the second starting device (3) ahead of the first starting device (2) to drive the crankshaft (1a) when the crankshaft (1a) is driven using both the first starting device (2) and the second starting device (3); The control device (4) determines, on the basis of at least one piece of information from a rotational speed, a torque and a current of the first starting device (2), whether a piston of the engine (1) can extend beyond top dead center in a first compression stroke or not; and The control device (4), after it is determined that the piston can go beyond top dead center, switches from the second starting device (3) to the first starting device (2) to drive the crankshaft (1a).

A powered fastener driver including a driver blade movable from a top-dead-center position to a bottom-dead-center position for driving a fastener into a workpiece. A driver may include a lifting assembly for providing torque to move the driver blade from the bottom-dead-center position toward the top-dead-center position, the lifting assembly including a rotary lifter configured to be selectively engageable with the driver blade, the rotary lifter having a plurality of lift pins and a roller disposed on at least one of the lift pins, wherein the roller includes a plurality of cam portions defined by cup-shaped recesses having a first radius oriented parallel to a rotational direction of the roller and a second radius perpendicular to the first radius, and wherein the driver blade includes a lift tooth having a crown disposed thereon, the crown configured to be engaged with at least one of the plurality of cam portions.

The present invention relates to an alternative two-stroke reciprocating internal combustion engine and power system thereof which eliminates the intake and compression phases of four-stroke Otto engines, and injects the fuel and the oxidising agent at high pressure directly into the combustion chamber or a prechamber at approximately the moment when the piston is at the top dead centre (TDC), using oxygen and / or air as the oxidising agent and hydrogen-based fuels, synthetic fuels, biofuels, alcohols, natural gas and mixtures thereof. At the same time, a spark is applied or combustion is produced by self-ignition, and expansion occurs until the piston reaches the bottom dead centre (BDC). The piston then starts to rise, the mechanically or electrically actuated exhaust valve opens and exhaust is discharged until the TDC is reached again, thereby repeating the cycle.

A motion generation device is configured to generate motion of a slide of a press device including the slide to which an upper die is attached, a bolster on which a lower die is placed, and a servomotor configured to move the slide reciprocally in the up and down direction. The motion generation device includes a motion generation section. The motion generation section is configured to generate a derivative motion of the slide at a cycle time different from the cycle time of the standard motion of the slide, such that the derivative motion includes the same motion as a first region of the standard motion including at least from top dead center to the end position of the molding region, and the speed of the slide at top dead center of the derivative motion is the same as the speed of the standard motion.

The utility model discloses a diaphragm adjusting device of a diaphragm compressor under low-negative-pressure air inlet. The diaphragm adjusting device comprises a piston assembly, a crosshead assembly, an air distribution disc and an oil distribution disc. The three metal diaphragms are arranged between the gas side diaphragm cavity and the oil side diaphragm cavity in an overlapped mode, and the middle diaphragm is provided with a guide groove to be communicated with the leakage detection opening; the electromagnet is arranged on the surface layer, close to the diaphragm side, of the oil distribution disc; the piezoelectric ceramics are respectively fixed in the machine body assembly and are close to an upper dead center and a lower dead center of the crosshead assembly; the springs are fixed on the two sides of the machine body assembly, are insulated from the crosshead assembly and are used for triggering the piezoelectric ceramics; the electromagnets are electrically connected with the piezoelectric ceramics respectively; the switch is attracted and controlled by the electromagnet to switch on and off of a circuit; the slide rheostat is connected in series with the electromagnet to adjust the adsorption force; the spring impacts the piezoelectric ceramic when the crosshead assembly moves to the upper stop point and the lower stop point, current is excited to enable the electromagnet to attract the switch, and then power-on and power-off of the electromagnet are controlled.

The invention relates to a method for operating a vehicle engine in order to regenerate a solid particle filter in an idle mode, in which a pre-ignition is delayed in such a way that an actual ignition takes place at the point in time when a piston is in a position after top dead center in the direction of rotation of the crankshaft. Meanwhile, the injection time of fuel into the intake air in the combustion chamber of at least one cylinder is shortened, so that the air-fuel ratio lambda is increased by at least 5% from 1.

To provide a lock mechanism used for a drain plug device and having a simpler structure.SOLUTION: The lock mechanism 57 has a turning part 53 turning around a turning shaft R1 by reciprocation of the operated part 7, and a transmission end part 54a provided at an end of the transmission part 54 and regulated to reciprocate in a linear direction, and the turning part 53 has a projection part 53b capable of reciprocating along an arc-shaped path. When the discharge port is in the open state, the projection portion 53b is disposed at the top dead point position or a position in the vicinity of the top dead point position, which is a position where the center of the projection portion R1 overlaps with an imaginary surface 54a including the rotation shaft V1 and parallel to the reciprocating direction of the transmission terminal portion center, so that even if a force in the backward direction is applied to the plug lid when the discharge port is in the open state, the rotation of the rotation portion 53 is restricted, and the transmission portion 54 can be locked in a state of being moved forward.SELECTED DRAWING: Figure 7

A powered fastener driver includes a drive blade movable from a top-dead-center (TDC) position to a driven or bottom-dead-center (BDC) position for driving a fastener into a workpiece, a piston coupled to the drive blade, a drive unit for providing torque to move the drive blade, a rotary lifter configured to receive torque from the drive unit in a first rotational direction for returning the drive blade from the BDC position toward the TDC position, and a gas spring assembly having a master supply cylinder in which gas is compressed by the piston in response to being moved from the BDC position toward the TDC position, a drive cylinder having a flange against which an end of the master supply cylinder is abutted, and an end cap secured to the master supply cylinder to apply a clamping force to the flange against the end of the master supply cylinder.

The invention relates to a compression ratio measuring system, method and device of a to-be-measured engine. The system comprises a liquid storage container, an image acquisition device and a computer device, the liquid storage container is communicated with the combustion chamber, so that the internal space of the liquid storage container and the combustion chamber form a containing space, the image acquisition device is connected with the computer device, and the containing space is used for containing liquid so that the liquid can be stored in the liquid when the crankshaft drives the piston to move in the air cylinder. The volume of the liquid in the liquid storage container is changed along with movement of the piston, the image acquisition device is used for acquiring images of the liquid in the liquid storage container, and the computer device is used for acquiring the images acquired by the image acquisition device, acquiring the maximum volume and the minimum volume of the liquid in the liquid storage container according to the images and displaying the maximum volume and the minimum volume. And determining the compression ratio of the to-be-tested engine according to the maximum volume and the minimum volume. By adopting the system, the upper dead center and the lower dead center of the piston do not need to be manually confirmed, and the measurement accuracy of the engine compression ratio is improved.