54 results about "Power stroke" patented technology

Embodiments are disclosed herein for detecting deterioration of a connecting rod large end bearing within an internal combustion engine including a crankshaft and an exhaust manifold, the internal combustion engine incorporated on a vehicle. A method includes providing an electronic control unit coupled to an engine, a first set of sensors positioned adjacent to a crankshaft for detecting crankshaft acceleration, a second set of sensors positioned adjacent to an engine exhaust manifold for detecting engine exhaust manifold pressure, and a display component and an auditory component coupled to the electronic control unit. The display component and / or the hearing component is activated when the first set of sensors detects that the crankshaft acceleration during the power stroke is reduced compared to a previous acceleration of the crankshaft during the power stroke, and the second set of sensors detects that the exhaust manifold pressure does not statistically differ from the expected exhaust manifold pressure.

The swing-arm double-gear power transmission mechanism is a type of engine that eliminates the crankshaft structure of the traditional cylinder piston connecting rod crankshaft engine, replacing it with a swing-arm double-gear power transmission mechanism. This mechanism consists of a straight rod fixed to the piston, a U-shaped gear carrier fixed to the straight rod, and two fork plates under the U-shaped gear carrier, each with a long, narrow opening in the middle. At the rear end of each fork plate, there is also a shaft hole. Between the two fork plates of the U-shaped gear carrier, a pair of meshing gears are installed. A connecting plate is installed on each side of the gears, and each connecting plate has a shaft hole corresponding to the gear shaft position, allowing for sliding fit with the gear shaft or a rolling bearing fit. After passing through the connecting plates, both ends of the gear shaft are fixed to a pair of swing arms. The other end of the upper gear's swing arm is fixed to the power output main shaft and the flywheel energy storage sub-shaft, respectively. The lower gear's swing arm... At the other end, it engages with the shaft holes or rolling bearings on the two fork plates of the U-shaped gear carrier. Driven by the engine starter, the main shaft transmits rotation to the upper gear of this structure, which in turn transmits it to the meshing lower gear. This, in turn, drives the U-shaped gear carrier to move along the direction of the cylinder piston, preparing the engine for the four-stroke power stroke. When the engine ignites and begins the power stroke, the piston drives the U-shaped gear carrier, and through the initial operating mode, the gear set, in turn, pushes the main shaft to continue rotating in the direction it began to rotate, performing power. At the end of the power stroke, the flywheel releases its stored energy, continuing to complete the other strokes of the engine, forming a continuous cycle of power delivery. Because of this continuous cycle, the main shaft continuously outputs power, eliminating all the defects of traditional crankshaft engines. This swing arm double-gear power transmission mechanism has an extremely simple structure, reliable operation, is very easy to manufacture, process, install, and maintain, has low cost, and extremely high thermal efficiency. It is suitable for all applications and equipment using traditional cylinder piston crankshaft engines.

The invention relates to a control method and a control device of a vehicle braking system, a vehicle and a storage medium, the vehicle braking system comprises a power stroke unit (PSU), a first solenoid valve, a second solenoid valve, a third solenoid valve, an energy accumulator and a brake fluid storage tank, and the volume of the energy accumulator at least allows a second volume of brake fluid to be stored. The method comprises the steps that when it is detected that the hydraulic brake assisting parking function is in an enabled state and a brake pedal is changed into a non-treaded state from a treaded state, a third electromagnetic valve is controlled to be opened, so that a second volume of brake fluid flows from brake calipers through the third electromagnetic valve and is stored in an energy accumulator; when it is detected that the braking action of the hydraulic braking assisting parking function is relieved, the first electromagnetic valve is controlled to be closed, and the second electromagnetic valve is controlled to be opened, so that the second volume of braking fluid flows back to the PSU from the energy accumulator through the second electromagnetic valve and then flows back to the braking fluid storage tank through the fluid supplementing opening and the communicating channel; therefore, brake fluid generated after pressurization of the brake control unit is discharged into the brake fluid storage tank from the brake calipers.

The invention discloses an engine secondary compression release braking device, an engine and a vehicle. The engine secondary compression release braking device comprises an intake valve assembly; the air inlet cam comprises a base circle part, a first protruding position and a second protruding position. The air inlet cam drives the air inlet rocker arm to rotate, so that the second end of the air inlet rocker arm moves towards the air inlet valve assembly, and the engine is in an acting stroke in the process that the first protruding position abuts against the air inlet rocker arm; the executing mechanism is located between the second end of the air inlet rocker arm and the air inlet valve assembly and used for abutting against the air inlet valve assembly and driving an air inlet valve of the air inlet valve assembly to be opened. The driving mechanism is used for driving the executing mechanism to move relative to the second end of the air inlet rocker. In the power stroke of the engine, air is fed through the air inlet valve, the amount of air in the air cylinder in the second compression release process of the engine is guaranteed, and therefore the braking power of the engine is guaranteed; the temperature of gas entering the air cylinder is reduced through air intake of the air inlet valve, and therefore the thermal loads of an oil nozzle, the air inlet valve and an exhaust valve of the engine are reduced.

The utility model discloses a four-stroke free piston engine, which comprises two groups of cylinders, two rocking gears, a one-way clutch and a transmission shaft, pistons of the two air cylinders in the same group are connected through push rods, racks are arranged on the two push rods respectively, one swing gear is meshed with the racks of the two push rods respectively, the other swing gear is meshed with the rack of at least one push rod, and the swing gears are in transmission connection with the corresponding transmission shafts through one-way clutches. Each air cylinder sequentially completes an air inlet stroke, a compression stroke, a power stroke and an exhaust stroke to form a cycle, a piston of one air cylinder always works and synchronously drives the other three air cylinders to complete the air inlet stroke, the compression stroke and the exhaust stroke respectively, and the locking directions of the two one-way clutches are opposite. Therefore, it is guaranteed that one of the two transmission shafts outputs torque, the other transmission shaft idles, and the idling direction of the transmission shafts is the same as the transmission rotation direction.

The invention relates to the technical field of data processing, in particular to an engine fault detection method and system. The method comprises the steps that the standardized energy deviation of the current working cycle is determined according to the working condition similarity of the current working cycle and multiple historical reference working cycles in the engine operation process and the vibration energy of vibration signals of all the historical reference working cycles; decomposing the current working cycle into a power stroke and a compression stroke, determining a stroke asymmetric index according to the angular velocity fluctuation degree of the power stroke and the angular velocity fluctuation degree of the compression stroke, and determining an instantaneous risk index of the current working cycle by integrating the standardized energy deviation and the stroke asymmetric index; and performing time sequence accumulation analysis on the instantaneous risk index to detect whether the engine has a fault or not. The method improves the accuracy and reliability of engine fault detection.

The invention discloses a novel technical scheme of a novel internal combustion engine, which is characterized in that a cylinder body of an air cylinder is extended to exceed the length of two air cylinders, cylinder covers are arranged at two ends, gear holes are formed in the middles of the air cylinders, two symmetrically connected pistons are arranged in the gear holes, a connecting body is provided with a strip-shaped concave gear, and four-stroke acting is performed twice; the working sequence is as follows: the piston 2 of the first air cylinder works, the piston 2 exhausts, the piston 3 exhausts, the piston 2 enters, the piston 3 compresses, the piston 2 compresses, the piston 3 works, the gears 20, 21, 24 and 25 are in gear transmission when the piston 2 works, the gears 20, 21, 22 and 23 are in gear transmission when the piston 3 works, the piston 4 enters, the piston 5 compresses, the piston 4 compresses, the piston 5 works, the piston 4 exhausts, the piston 4 exhausts, and the piston 5 enters. Therefore, the power of a traditional four-cylinder engine can be reached or even exceeded by only combining two cylinders, the volume of the engine is reduced, the weight of the engine is reduced, the stability of the piston is improved, and the heat efficiency is improved.

This invention relates to a crankshaft unit, an aero-engine, and an aircraft, belonging to the field of aerospace technology. It solves the problems of excessive weight and vibration when converting automotive engines for aero-engine use. The invention is for automotive-to-aero-engine conversion and includes a crankshaft, a crankshaft pulley, and a flexible disc. The flexible disc is fitted onto one end of the crankshaft and is used to connect to the engine's starter. The crankshaft pulley is located at the end of the crankshaft opposite to the flexible disc. An annular groove is provided on the outer peripheral wall of the crankshaft pulley, and the bottom of the groove has a damping section, which is the impact point of the engine piston during power stroke. This invention achieves a weight reduction similar to that of a dedicated aero-engine when converting an automotive engine for aero-engine use, while also providing superior vibration damping performance.

The invention is called "Cutting Blade", which is a device installed in the engine intake pipe. Through friction, cutting, and heat transfer, it combines the air entering the engine with atomized fuel to form a high-quality mixture, enabling more energy to be released during the explosion and power stroke, and the mixture to burn more completely, achieving the purpose of fuel savings and exhaust gas reduction. Its core principle is to cut, refine, and uniformly heat the air entering the engine. The dominant thinking in the product design and structure is to not only cut the air flowing through the intake pipe but also minimize the resistance of this device to hinder the air from entering the engine. Practice has proven that installing this device can effectively reduce the phenomenon of altitude sickness in vehicles. The technical field to which the invention belongs is: automotive power efficiency, automotive exhaust gas reduction, and technologies for dealing with automotive altitude sickness. The inventor solved the problem of abnormal noise generated by previous similar products during high-speed driving through ingenious design. The result was obtained through a total of six design modifications during the actual test of 90,000 kilometers in seven years.

Disclosed herein are high pressure systems and components thereof including an intensifier pump and asymmetric ram piston. The asymmetric ram piston includes a first effective area upon which a force is exerted during a power stroke of the intensifier pump and a second effective area upon which a force is exerted during a recovery stroke of the intensifier pump. The first and second effective areas are different sizes. Also disclosed herein are methods of assembly of the asymmetric ram piston and methods of operation of the intensifier pump to pressurize a fluid.

The invention relates to the technical field of engine knock detection and control, in particular to an engine knock energy prediction method and device, a vehicle, a storage medium and a product, and the method comprises the steps: obtaining an operation data set of an engine test, including operation data of an engine in a plurality of acting stages and real knock energy corresponding to each acting stage; a training data set and a verification set are generated according to the operation data set, each of the training data set and the verification set comprises a data sample and a real label, the data samples comprise operation data of the engine in the current acting stage, and the real labels are real knocking energy of the data samples; and training a pre-constructed knock energy prediction model by using the training data set, verifying the knock energy prediction model by using the verification set, and predicting the knock prediction energy of the engine by using the currently collected operation data and the knock energy prediction model. Therefore, the problem that the detonation energy prediction precision is poor due to the fact that differential operation working conditions are generated by the hybrid power engine due to power coupling in the related technology is solved.

The utility model discloses a four-stroke free piston engine which comprises two groups of air cylinders which are oppositely arranged, and further comprises a swing gear, a first one-way clutch, a second one-way clutch, a first power output piece and a second power output piece, the swing gear is arranged in a fixed-axis rotating mode, and pistons of the two air cylinders in each group are connected through a push rod. The swing gear is meshed with racks on the two push rods, each air cylinder sequentially completes an air inlet stroke, a compression stroke, an acting stroke and an exhaust stroke, the four strokes form a working cycle, a piston of one air cylinder does work all the time, and the other three air cylinders are synchronously driven to complete the air inlet stroke, the compression stroke and the exhaust stroke respectively. In this way, complex parts such as a push rod, a crankshaft, a high-pressure oil bearing and a high-pressure oil pump in the prior art can be omitted, linear reciprocating motion of the piston is converted into rotating motion so as to output power in the rotating form, meanwhile, the efficiency of the engine is improved, and the engine is suitable for being used as an engine of vehicles such as HEV, PHEV and REEV.

The utility model relates to the technical field of pistons, in particular to a dual-fuel steel top aluminum skirt piston which comprises a piston body and a particle groove, the particle groove is formed in the upper end of the piston body, a ventilation folding channel is formed in the inner side of the piston body, an on-off assembly is installed on the inner side of the ventilation folding channel, a through opening is formed in the inner side of the piston body, and a limiting hole is formed in the inner side of the piston body. A limiting hole is formed in the piston body, a first silicon rubber sealing ring is fixedly connected to the inner side of the limiting hole, a movable groove is formed in the inner side of the piston body, a first magnetic plate is fixedly connected to the upper end of the movable groove, the on-off assembly comprises a gravity metal block, a second silicon rubber sealing ring is fixedly connected to the bottom end of the gravity metal block, and a hollow sliding column is fixedly connected to the bottom end of the gravity metal block. According to the device, an air duct can be formed in the piston by utilizing the force of the reciprocating motion of the piston in an inertia mode, so that the effect of continuously removing carbon particles is achieved, meanwhile, the power stroke of the piston is not influenced, and the service life of the piston is ensured.

The invention relates to a device (1) for closing and clamping a mould, in particular an injection mould, comprising: a first carrier plate (2), a first mould part being preferably arranged on the first carrier plate (2); a second carrier plate (4) which is arranged parallel to the first carrier plate (2); at least one rod (6) which extends perpendicularly away from the first carrier plate (2) and which is guided through an opening or a recess in the second carrier plate (4) such that the second carrier plate (4) is movable along the rod (6) relative to the first carrier plate (2); at least one controllable clamping / holding device (7) which is operatively connected to the second carrier plate (4) and which is designed and intended, when activated, to hold the second carrier plate (4) on the rod (6) in a first relative position with respect to the first carrier plate (2), and optionally, starting from the first relative position, to move the second carrier plate (4) towards the first carrier plate (2) into a second relative position by means of a power stroke and to hold it there, and which is designed and intended, when deactivated, to release the second carrier plate (4) for movement along the rod (6); and at least one joint arrangement (10) which permits four degrees of freedom, namely two translational degrees of freedom (x, y) in a plane (E) parallel to the carrier plates (2, 4), and two rotational degrees of freedom (RotX, RotY) about directions perpendicular to the rod (6).

The instant invention includes systems for and methods of maximizing efficiencies in an internal combustion engine while minimizing costs and weight for the same and while also minimizing maintenance requirements for the same. Such systems include a compression assembly for compressing fluid to a desired pressure for combustion (such as above 220 psi), a combustion assembly configured to receive at least a portion of the compressed volume of air for each power stroke, and an electrolyzer for separating out hydrogen from the fluid for use as additional fuel during combustion. In this way, the power stroke of the engine is independent of the compression stroke of the engine, thereby eliminating or otherwise minimizing transitional losses associated with the same.

The invention discloses a pre-combustion chamber spark plug ignition system and method and related devices, and relates to the field of engines, and the system comprises a spark plug, a spark plug bushing, an air outlet electric control valve, an air inlet electric control valve, a pre-combustion chamber and an engine controller. When condensate water is formed on the spark plug electrode, the air inlet electric control valve is controlled to be opened, the air outlet electric control valve is controlled to be closed, air in the main combustion chamber enters an air cavity of the spark plug lining, when the air in the spark plug lining reaches the air pressure peak value, the air inlet electric control valve is closed, and the air pressure peak value of the air in the spark plug lining is kept unchanged. And when the piston moving part reaches an acting lower dead center, the air outlet electric control valve is controlled to be opened, so that air in the air cavity of the spark plug bushing is blown to the spark plug electrode to purge condensed water. According to the application, the gas in the main combustion chamber flows into the gas cavity of the spark plug bushing, and the gas in the gas cavity of the spark plug bushing is utilized to purge the condensed water on the spark plug electrode, so that the spark plug electrode is recovered to be dry, and the starting of the engine is realized.

The application belongs to the technical field of underwater propeller, and discloses a control method for periodic swing of bionic hydrofoil, which controls the hydrofoil to swing according to the following periodic swing rule: each swing period of the periodic swing rule is composed of two half periods which are mirror-symmetric about the center position; each half period is sequentially composed of a recovery stroke and a power stroke, wherein the ratio of the maximum angular velocity of the power stroke to the maximum angular velocity of the recovery stroke, i.e. the speed ratio, satisfies the application. Through the provided periodic motion rule, the rigid impact is eliminated, the residence time of the hydrofoil at the center position is prolonged, the propulsion efficiency and the forward distance are effectively improved, and reliable technical support is provided for the engineering propulsion of rigid hydrofoil.

The invention discloses a range extender NVH (Noise Vibration and Harshness) optimization method, a range extender and an electric vehicle, and aims to improve the power generation load power of a range extender controller and reduce the power generation load power of the range extender controller in two stages of an intake stroke and a compression stroke in an adjustment period of the range extender when set conditions are met. Hardware does not need to be changed, NVH optimization of the whole vehicle is achieved by dynamically adjusting the generated power according to the rotating speed difference of the four strokes, and rotating speed jump impact is effectively restrained.

Embodiments of a method for detecting deterioration of a connecting rod bearing in an internal combustion engine having a crankshaft and an exhaust manifold in a vehicle are described herein. A method includes providing an electronic control unit connected to the engine, a first set of sensors for sensing crankshaft acceleration disposed adjacent to the crankshaft, a second set of sensors for sensing engine exhaust manifold pressure disposed proximate the engine exhaust manifold, and a display component and an audible component connected to the electronic control unit.The display component and / or the audible component is activated when the first set of sensors detects a reduced crankshaft acceleration during a power stroke compared to a previous acceleration of the crankshaft during a power stroke and the second set of sensors detects an exhaust manifold pressure that is not statistically significantly different from the expected exhaust manifold pressure.

A double-circulation high-power engine is characterized in that an engine piston is designed into double layers which are overlapped together, a lower-layer piston is a main moving piston, an upper-layer piston is an air suction and exhaust piston, and the upper-layer air suction and exhaust piston slides through a positioning sliding rod and a positioning guide pipe in the center of the main moving piston and can be separated from the lower-layer main moving piston to do up-down relative movement; a through conical round hole is formed in the air suction and exhaust piston, and a conical cover plate capable of moving upwards is arranged on the conical round hole; a main movement piston rotates one circle on a crank arm to complete circulation of a compression stroke and a power stroke, an air suction and exhaust piston moves upwards with the help of a separation executing mechanism when the crank arm of the main movement piston rotates to the range of 155 degrees to 205 degrees to complete circulation of the two strokes of air suction and air exhaust, and therefore the circulation of four strokes is actually completed. And the oil-saving effect of a four-stroke engine is also achieved, and the power is doubled.

According to the novel internal combustion engine transmission device, the length of a piston is increased, the tail end of the piston is limited through a sliding sleeve, a rack capable of moving up and down under the timely effect of an eccentric cam is additionally arranged in the middle of the piston, an independent power output shaft is arranged on one side of the piston, and a pulsation device is formed by combining a plurality of perfect circle gears and oval gears. When the crank connecting rod mechanism works, the crank connecting rod mechanism is timely engaged with or disengaged from the rack on the piston, so that the power obtained by the piston in a power stroke forms torque on the independent power output shaft through the pulsation device, the original crank connecting rod mechanism does not have a power output function and only assists the piston in performing various stroke actions, and the defect of low transmission efficiency of the crank connecting rod mechanism is avoided; therefore, the heat engine efficiency of the internal combustion engine is greatly improved.

A pneumatic motor for rotating an axle including: a. a housing including: b. an air intake port; c. an air exhaust port; d. at least two cylinders; each cylinder being positioned radially from the axle; e. at least two air channels in communication with each cylinder; f. at least two pistons, each piston attached to the axle by a connecting rod, each piston and respective connecting rod being radially aligned, each piston to be received in one of said at least two cylinders; each connecting rod being attached centrally offset in relation to a central axis of the axle; wherein when one connecting rod and piston are in power stroke, the other connecting rod and piston are in exhaust stroke.

The present invention relates to an energy-saving and efficiency-enhancing linear drive cylinder and its usage method. The drive cylinder includes a main cylinder body, a front cover, and a rear cover; a main piston and a main piston rod are arranged in the main cylinder body; a secondary piston is further arranged in the main cylinder body, and the secondary piston is located between the main piston and the rear cover; a rapid propulsion chamber is arranged along the secondary piston and / or the secondary piston rod; a main pressure chamber is formed along the main cylinder body between the secondary piston and the main piston. When the drive cylinder is in use, drive fluid is injected into the rapid propulsion chamber to achieve rapid extension, and drive fluid is injected into the main pressure chamber to achieve main pressure output. By improving the internal structure of the linear drive cylinder and combining different drive fluid injection methods, the present invention improves the operating speed during idle or low-power strokes and reduces the fluid consumption, thereby improving the operating efficiency of the equipment and reducing the power consumption of the drive fluid station.

The present invention discloses a structure and method for improving the sealing performance of a hydrogen injector, belonging to the field of engine technology, comprising an outer shell of an electromagnetic valve, an electromagnetic valve body arranged in the outer shell of the electromagnetic valve, and an integrated coil wound around the outer periphery of the outer shell of the electromagnetic valve; the electromagnetic valve body comprises a needle valve, a moving iron core, a spring and a static iron core, the centers of the moving iron core and the static iron core are both provided with a hollow area, the static iron core is arranged in the upper area of ​​the electromagnetic valve body, the moving iron core is arranged in the lower area of ​​the electromagnetic valve body, the spring is arranged in the hollow area of ​​the static iron core, and the needle valve passes through the hollow area of ​​the moving iron core and is connected to the spring; and the structure and method comprise four stages: a needle valve opening stage, a needle valve continuously opening stage, a needle valve seating and closing stage, a needle valve already seated, a late compression stroke stage and an early power stroke stage; the structure and method provided by the present invention effectively improve the sealing characteristics of the existing hydrogen nozzle, and improve the reliability and service life of the hydrogen nozzle.

To provide a more reliable internal combustion engine that addresses concerns about both environment and efficiency.SOLUTION: A self-feeding type four-stroke one-cycle combustion cylinder is partitioned into a pressurized space 102 and a combustion space 112, and a bore size of the cylinder is larger than that of a crank shaft piston 108 accommodated inside. The cylinder includes: an internal structure 106 that is located within the cylinder to act as a secondary piston and is configured to perform piston motion integrally with the crank shaft piston 108; and an oil socket that has a first outer sleeve 114 designed to surround the crank shaft piston 108 and a second inner sleeve 120. This structure can facilitate the piston motion, cause the oil socket to enable direct lubrication of an inner surface of the cylinder from a sump of engine oil and to support exhausting and scavenging without contaminating the combustion space 112, and guide air to a space before compression in a power stroke.SELECTED DRAWING: Figure 1

A method of pumping produced liquids from the depths of a wellbore during a reset stroke and a power stroke of a pump located downhole, wherein the pump comprises an upper barrel, a lower barrel, an upper plunger within the upper barrel, a lower plunger within the lower barrel, an upper ported intake sub with an upper outlet check valve and an upper intake check valve, a dual ported mandrel, and a lower ported intake sub with a lower intake check valve and a lower outlet check valve.

A system includes a condensate injection system configured to fluidly couple to a combustion chamber of a reciprocating engine and an exhaust gas recirculation (EGR) system of the reciprocating engine. The condensate injection system includes a condensate tank configured to store condensate collected from the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate tank. The condensate injection system also includes an injector fluidly coupled to the pump. The injector is configured to inject condensate into the combustion chamber during a first portion of an engine cycle of the reciprocating engine. The first portion of the engine cycle includes at least part of a power stroke and / or an exhaust stroke of the engine cycle.

A self-charging four-stroke single-cycle combustion cylinder for an internal combustion engine includes: a cylinder defining an internal space divided into a pre-compression space and a combustion space, in which a bore diameter of the cylinder is larger than a bore diameter of a crankshaft piston accommodated therein; an occupancy structure located within the cylinder, acting as an auxiliary piston and configured to reciprocate in unison with the crankshaft piston; the oil bearing seat is provided with a first outer sleeve and a second inner sleeve, and the second inner sleeve is designed to surround the crankshaft piston and is convenient for reciprocating motion in the crankshaft piston; wherein the oil socket is configured for direct lubrication from the engine sump to the inner surface of the cylinder without contaminating the combustion space, and is configured to support exhaust scavenging; and an intake assembly capable of directing air into the pre-compression space during the power stroke, where the air is inductively transferred to the combustion space during the retraction stroke.

The present application discloses a method and device for confirming abnormal air pressure in the air path of a dual-fuel nozzle, relating to the field of automotive technology. The method comprises the following steps: obtaining the current oil-air pressure differential of the engine; if the current oil-air pressure differential of the engine is greater than a first preset oil-air pressure differential of the engine, obtaining the speed roughness of each cylinder of the engine; and determining the position of the cylinder with abnormal air pressure based on the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold. By obtaining the speed roughness of each cylinder and determining the position of the cylinder with abnormal air pressure based on the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold, the abnormal cylinder is locked, thereby improving the reliability of the engine. The speed roughness of the cylinder is based on the crankshaft angular acceleration corresponding to the power stroke of each cylinder obtained from the engine crankshaft speed signal. Based on the deviation between the crankshaft angular acceleration corresponding to the power stroke of each cylinder and the speed roughness threshold, it can be determined whether the current cylinder has an abnormal air pressure.

The present application relates to the technical field of data processing, in particular to an engine fault detection method and system, the method comprising: determining a standardized energy deviation of a current working cycle by a working condition similarity of the current working cycle and a plurality of historical reference working cycles and vibration energy of vibration signals of each historical reference working cycle during engine operation; decomposing the current working cycle into a power stroke and a compression stroke, and determining a stroke asymmetry index according to an angular velocity fluctuation degree of the power stroke and an angular velocity fluctuation degree of the compression stroke; determining an instantaneous risk index of the current working cycle by integrating the standardized energy deviation and the stroke asymmetry index; and performing time series accumulation analysis on the instantaneous risk index to detect whether the engine has a fault. The method improves the accuracy and reliability of engine fault detection.