353 results about "Top dead center" patented technology

A powered fastener driver including a driver blade movable from a top-dead-center (TDC) position toward a bottom-dead-center (BDC) position for driving a fastener into a workpiece, a nosepiece through which the fastener is driven into the workpiece that is configured to guide the driver blade and the fastener into the workpiece, and a lifting assembly for providing torque to move the driver blade from the (BDC) position toward the TDC position. The lifting assembly includes a rotary lifter for engaging the driver blade to move the driver blade toward the (TDC) position. The rotary includes a body having a central aperture, a flange radially extending from the body that defines an outer radial profile configured to contact the driver blade to return the driver blade from the BDC position toward the TDC position, and a non-rotating mounting shaft coupled to the central aperture to rotatably support the rotary lifter thereon.

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.

A fastener driver includes a firing pin, a piston connected to the firing pin, a driving member driving a striking assembly to move backward to a top dead center position, and an energy storage device driving the striking assembly to move forward to a bottom dead center position to output an impact force. The distance L3 between the top dead center position and the bottom dead center position is defined as the stroke of the striking assembly, the fastener driver is configured to drive a fastener within a preset length LA to move, and the ratio of the stroke of the striking assembly to the preset length is less than or equal to 1.5 to 1.

The invention relates to the technical field of engines, in particular to a piston combustion chamber for a diesel and natural gas engine and the engine, and the piston combustion chamber for the diesel and natural gas engine comprises an omega-shaped pit. The straight opening type omega-shaped pit structure is adopted, compared with a traditional ignition type combustion chamber, the ineffective conical volume in the center of the combustion chamber is removed, the top dead center injection diffusion combustion mode is better met, the air utilization rate is higher, the compression ratio is higher, and higher heat efficiency can be better achieved; compared with a traditional necking omega-shaped diesel engine combustion chamber, a plurality of necking structures are removed, the first annular concave face and the second annular concave face are designed, the characteristic of natural gas injection is better met, the front end space of flames is fully released, the air utilization rate is increased, the heat transfer loss is reduced, and the combustion efficiency and the heat efficiency are improved; due to the design of the large-curvature concave surface, the problems of heat load concentration and particle friction caused by a sharp structure can be avoided, and the problems of out-of-control combustion, knocking and engine damage are reduced.

The utility model discloses a double-cone oil cavity structure of a high-rotating-speed diaphragm compressor. The double-cone oil cavity structure comprises a cylinder cover and a supporting assembly. The cylinder cover is installed on the supporting assembly, a diaphragm and an oil distribution disc are arranged between the supporting assembly and the cylinder cover, a first oil cavity is formed between the supporting assembly and the bottom of the oil distribution disc, the oil distribution disc is provided with an oil outlet channel, the bottom of the oil distribution disc is provided with a first conical protruding part, a piston hole is formed in the supporting assembly, and a piston is arranged in the piston hole. The top of the piston is in a second cone shape, and the first cone shape and the second cone shape are oppositely arranged. The top of the piston is in the second cone shape, and the first cone-shaped protruding part is arranged at the bottom of the oil distribution disc, so that when the piston moves from a lower dead center to an upper dead center, hydraulic oil can be guided to flow in the first oil cavity in the radial direction, impact of the hydraulic oil on the oil distribution disc is reduced, flow loss of the hydraulic oil is reduced, and the service life of the hydraulic oil is prolonged. Therefore, the cavitation phenomenon is prevented.

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 powered fastener driver includes a housing, a cylinder within the housing, the cylinder containing a pressurized gas, a piston within the cylinder and movable from a top-dead-center position to a bottom-dead-center position, a driver blade movably coupled to the piston, a lifter, a drive unit configured to provide torque to the lifter, and a sensor. The driver blade has a plurality of teeth defining a predetermined number of edges. The sensor is configured to detect an edge of one or more of the plurality of teeth and a controller in communication with the drive unit and the sensor. The controller is configured to count a number of edges detected by the sensor, compare the number of detected edges to the predetermined number of edges, and stop the drive unit when the number of detected edges is less than the predetermined number of edges.

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.

The invention discloses a vehicle control method and device, computer equipment and a storage medium, relates to the technical field of vehicle control, and aims to solve the problems that abnormal sound is easy to generate during engine starting, and the abnormal sound not only influences user experience, but also accelerates fatigue damage of a transmission part. The method comprises the steps that in response to control over a generator to drag an engine to run to a compression stroke, the generator is controlled to increase the output torque at a first change rate, and the crankshaft rotation angle and the crankshaft rotation speed fluctuation rate of the engine are obtained; if the crankshaft rotation angle is smaller than or equal to the preset rotation angle corresponding to the compression top dead center and the crankshaft rotation speed fluctuation ratio is larger than or equal to the first preset threshold value, the generator is controlled to increase the output torque at a second change rate, and the second change rate is smaller than the first change rate; and if the crank angle is greater than the preset angle, controlling the generator to reduce the output torque at a third change rate.

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 fuel cell system air back pressure valve state detection method and system belong to the fuel cell system field, and comprise: controlling an air back pressure valve opening according to a calibration top dead center, determining whether an actual opening is less than the calibration top dead center, if yes, updating the value of the calibration top dead center to the actual opening, and if not, updating the value of the calibration top dead center to the actual opening; after the value of the calibrated top dead center is updated to be the sum of the actual upper opening and the preset value, a first opening instruction is generated again; the opening degree of the air back pressure valve is controlled according to the calibrated bottom dead center, whether the actual lower opening degree is larger than the calibrated bottom dead center or not is judged, if yes, the value of the calibrated bottom dead center is updated to be the actual lower opening degree, and if not, after the value of the calibrated bottom dead center is updated to be the difference between the actual lower opening degree and preset data, a second opening degree instruction is generated again; and according to the updated calibrated bottom dead center, performing sealing judgment on the air back pressure valve to obtain a sealing result. Accurate upper and lower dead centers of the air back pressure valve can be obtained, so that the opening degree adjusting precision and the sealing performance are improved.

On the base platform (1) there is an electric motor (2) connected using a horizontal central shaft (4) with a circular gravity flywheel (3) provided with retaining pins (10) along its perimeter. On the retaining pin (10) there is a rotary-mounted gravity arm (5) with the centre of gravity outside the retaining pin (10). In the upper dead end of the gravity flywheel (3) there is a tilt mechanism of gravity arms (5) to their working position. In the working position the gravity arms (5) are provided with latching elements, e.g. one-direction bearings by means of which the gravity arms (5) are attached on the retaining pins (10). The equipment has a tilt mechanism of gravity arms (5), consisting e.g. of a gearwheel (13) and a geared rack (14), which turns the gravity arm (5) to the working position.

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.

The present invention provides a motion generating device, a punching device, and a motion generating method. The motion generating device (3) is a motion generating device for generating the motion of a slider (11) of a punching device (5) having a slider (11) mounted with an upper mold (7a), a pad (12) carrying a lower mold (7b), and a servo motor (15) for reciprocating the slider (11) in the up-down direction. The motion generating device has a motion generating unit (32). The motion generating unit (32) makes the standard motion (Mi) of the slider (11) in the cycle (TStd) at least including the first area (Mim (1) from the top dead center to the end position of the forming area, and makes the speed of the slider (11) at the top dead center the same as the speed of the standard motion (Mi), thereby generating a derived motion (Mim) of the slider (11) in a cycle (Tm) different from the cycle (TStd).

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.