749results about "Crankcase ventillation" patented technology

Described herein are engine systems, closed crankcase ventilation systems, and hot filter assemblies that are configured to filter out contaminants from the closed crankcase ventilation system prior to being returned to an air intake of the engine system. In some examples, a closed crankcase ventilation system can include an engine comprising a crankcase, an oil separator coupled to the crankcase, and a hot filter assembly coupled to the oil separator and mounted to an exhaust manifold of the engine or a turbine housing of a turbocharger. The hot filter assembly comprises a housing defining a cavity, a gas inlet fluidly coupled between the oil separator and the cavity, a gas outlet fluidly coupled between the cavity and an air intake of the engine, and at least one baffle extending across the cavity and defining a first and second gas pathways on opposite sides of the baffle.

The utility model discloses an oil-gas separation mechanism and an engine, the oil-gas separation mechanism comprises an air inlet cam shaft, a chain wheel, a centrifugal separation disc and a breather pipe, and the air inlet cam shaft is provided with a first channel penetrating through the two ends of the air inlet cam shaft; the chain wheel is meshed with a timing chain of an engine and used for driving the air inlet cam shaft to rotate. The centrifugal separation disc is connected with one end of the air inlet cam shaft and provided with a separation cavity, the separation cavity communicates with the first channel, fan blades are arranged in the separation cavity, the centrifugal separation disc rotates to suck mixed oil gas into the separation cavity, and the fan blades guide gas into the first channel and throw engine oil out of the separation cavity. The breather pipe communicates with the end, away from the centrifugal separation disc, of the first channel and is used for exhausting gas in the first channel. According to the oil-gas separation mechanism, the oil-gas separation structure can be arranged on the air inlet cam shaft, the space occupied by the oil-gas separation structure in an engine is reduced, the internal structure of the engine is simplified, and the manufacturing difficulty and manufacturing cost of the engine are reduced.

The utility model discloses an air cylinder assembly with a crankshaft cavity exhaust channel and an engine, and relates to the technical field of engines. Comprising a cylinder block body, and a plurality of crankshaft cavities communicating side by side are formed in the cylinder block body; a main blow-by channel is formed in the front end of the cylinder block body, and an auxiliary blow-by channel is formed in the rear end of the cylinder block body. A front-end air communicating hole is formed in the position, close to the front end of the air cylinder body, of the first crankshaft cavity and can communicate with the main air communicating channel. A rear-end blow-by hole is formed in the tail crankshaft cavity close to the rear end of the cylinder block body and can be communicated with the auxiliary blow-by channel; one path of oil gas in the crankshaft cavity is discharged to the oil-gas separator gas taking hole through the main blow-by channel via the front-end blow-by hole, and the other path of oil gas is discharged to the oil-gas separator gas taking hole through the auxiliary blow-by channel via the rear-end blow-by hole; and an oil-gas conveying path is prolonged, so that oil-gas separation is more thorough, and the oil-gas separation effect is further improved.

The invention relates to the technical field of automobile oil-gas separators, and discloses an active oil-gas separator, an oil-gas separation method and an automobile. The fine separation module comprises a driving structure, a separation rotor and a first bearing, and the separation rotor comprises a rotating shaft, an impeller, filter cotton and a bypass valve; the impeller is provided with a first oil-gas channel and a second oil-gas channel, and the bypass valve blocks a top opening of the second oil-gas channel. An oil baffle cover is arranged on the impeller, and is used for blocking a path from the second oil-gas channel to the first bearing; a third oil-gas channel is arranged between the oil blocking cover and the first bearing, a sealing cover is arranged at the upper end of the first bearing, and the sealing cover blocks the path, leading to the inner cavity of the first bearing, of the third oil-gas channel. The active oil-gas separator has the advantages that the active oil-gas separator can prevent clean lubricating grease in the bearing from being scoured and polluted, and separated engine oil and hydrocarbon can be discharged in time.

The invention relates to a method for determining the hydrogen content in an exhaust tract (130) of a hydrogen internal combustion engine (100) and to a hydrogen internal combustion engine (100) that has combustion chambers (110) and an oxygen sensor (140), which is provided in the exhaust tract (130) of the hydrogen internal combustion engine (100) and is designed to generate an oxygen signal that is representative of the oxygen content in the exhaust gas of the hydrogen internal combustion engine (100). The method according to the invention has the steps of determining a specified operating mode of the hydrogen internal combustion engine (100) during which substantially no combustion processes of an air-hydrogen mixture take place within the combustion chambers (110); receiving an oxygen signal from the oxygen sensor (140) in the specified operating mode of the internal combustion engine (100); and determining the hydrogen content in the exhaust gas of the hydrogen internal combustion engine (100) at least partly on the basis of the oxygen signal received from the oxygen sensor (140).

The present application belongs to the technical field of hydrogen engine, and particularly relates to an emulsified machine oil demulsification device and method for hydrogen engine, which can be used for solving the problem of emulsified machine oil of hydrogen engine in cold start or low temperature environment. The device comprises a vortex tube system, an emulsified machine oil heating system, an oil-gas separation system and a double-oil tank interaction system. The vortex tube system is communicated with the engine exhaust pipe to deliver exhaust heat to the emulsified machine oil heating system, and phase change material is used to realize constant temperature heating of the emulsified machine oil. Under the joint action of constant high temperature and demulsifier, efficient demulsification of the emulsified machine oil is realized. At the same time, the cold gas output by the vortex tube system is beneficial to the liquefaction and discharge of the separated water vapor. The double-oil tank interaction system can separate the emulsified machine oil and non-emulsified oil, so that the machine oil passing through the hydrogen engine oil pump is non-emulsified oil, and the normal lubrication of the hydrogen engine is ensured. The energy of the whole system comes from the engine exhaust energy, without additional energy, which conforms to the idea of energy saving and emission reduction.

The invention discloses a hydrogen engine crankcase hydrogen concentration control method, and relates to the field of hydrogen engines, and the method comprises the steps: placing a hydrogen engine on a rack for testing, and obtaining a target hydrogen concentration, an actually measured hydrogen concentration and a crankcase blow-by amount; according to the target hydrogen concentration, the actually measured hydrogen concentration and the crankcase blow-by amount, the target working condition supplementary air amount is calculated; according to the target working condition supplementary air amount, a full-working-condition supplementary air amount database is generated based on the rotating speeds and loads of the different working conditions; obtaining the amount of fresh air needing to be supplemented under the current target working condition according to the full-working-condition air supplementing amount database; the air inlet pressure, the air inlet temperature and the crankcase pressure are obtained; the method comprises the following steps: calculating the opening degree of a throttle valve by combining the air inlet pressure, the air inlet temperature and the crankcase pressure, comparing the hydrogen concentration measured by a hydrogen concentration sensor according to the current target working condition with the target hydrogen concentration to obtain a hydrogen concentration deviation and generate a corrected fresh air amount, and carrying out closed-loop control on the actual crankcase hydrogen concentration by adjusting the opening degree of the throttle valve.

The invention relates to a method for monitoring the ventilation of a crankcase (120) of a hydrogen internal combustion engine (100) and to a hydrogen internal combustion engine (100), which has combustion chambers (110) and a gas sensor (140) that is provided in the exhaust tract (130) of the hydrogen internal combustion engine (100) and is designed to generate a gas signal that is representative of the hydrogen content or oxygen content in the exhaust gas of the hydrogen internal combustion engine (100). The method according to the invention has the steps of: determining a specified operating mode of the hydrogen internal combustion engine (100) during which substantially no combustion processes of an air-hydrogen mixture take place within the combustion chambers (110); receiving a gas signal from the gas sensor (140) in the specified operating mode of the hydrogen internal combustion engine (100); determining the hydrogen content in the exhaust gas of the hydrogen internal combustion engine (100) at least partly on the basis of the received gas signal; and determining a functional ventilation of the crankcase (120) if the determined hydrogen content in the exhaust gas of the hydrogen internal combustion engine (100) exceeds a specified hydrogen content threshold value.

The invention relates to the technical field of hydrogen engines, in particular to a hydrogen internal combustion engine and a scavenging control method of the hydrogen internal combustion engine. The hydrogen internal combustion engine comprises an engine cylinder body assembly, a supercharger, an air filtering device, an air supplementing part, an air outlet part and a control device, the air supplementing part comprises a first air supplementing pipeline and at least two second air supplementing pipelines, and an air outlet of the air filtering device is communicated with the first air supplementing pipeline and an air inlet of the supercharger. One end of the first air supply pipeline is communicated with the air filtering device, the other end of the first air supply pipeline is communicated with the crankcase, the cylinder cover is communicated with an air outlet of the supercharger through at least one second air supply pipeline, the crankcase is communicated with the air outlet of the supercharger through at least one second air supply pipeline, and the air outlet part is communicated with the crankcase. The control device is electrically connected with the air supply part and the air outlet part. According to the hydrogen internal combustion engine, through the design of the multiple gas supplementing pipelines, the hydrogen concentration can be effectively reduced, and excessive hydrogen gathering is avoided.

A first passage communicating a portion downstream side of the compressor in the intake passage and an upstream side of the intercooler with the crankcase, a second passage communicating a portion downstream of the intercooler in the intake passage with the crankcase, and a third passage communicating a portion upstream of the compressor in the intake passage with the crankcase are installed in the turbocharged engine, and a switching valve for switching between a state in which the first passage communicates and the second passage is blocked, and a state in which the first passage is blocked and the second passage communicates is provided.

The utility model relates to an oil-gas separation device in a crankcase in an internal combustion engine, in particular to an efficient oil-gas separator device which comprises a main body and a main body base. The main body base is provided with an oil gas inlet and an oil outlet which are respectively positioned on two sides of the main body base, the main body base is provided with a mixed gas inlet, and the upper part of the inner side of the mixed gas inlet is provided with a turbulent flow adsorption grid plate; an integrated separation filter element, a first filter plate and a second filter screen are arranged in the main body, a filter safety valve, a spring connecting rod and a filter element fixing partition plate are arranged in the integrated separation filter element, the first filter plate is located at the upper end of the interior of the main body, and filter holes are formed in the lower portion of the second filter screen. The oil-gas separation and filtration device has the advantages that the internal design is compact, the occupied volume space is small, and the oil-gas separation and filtration effects are good.

The utility model provides an oil-gas separator which comprises a shell, the shell comprises a first shell body and a second shell body, the first shell body is provided with an inlet and a gas outlet, a first bearing is arranged in the first shell body, the side, close to the inlet of the first shell body, of the first bearing is in sealed connection with the inner wall of the first shell body, and a second bearing is arranged in the second shell body; the second shell is connected with the first shell, and an outlet for liquid to flow out is formed in the second shell; the oil-gas separation device is arranged in the shell body; and the exhaust pipe is connected with the air outlet of the first shell. According to the oil-gas separator, solid particles in a gas-liquid mixture can be prevented from entering the first bearing, the internal structure of the oil-gas separator is simplified, and the service life of the first bearing is prolonged.

A system including an engine capable of operating with fuel containing hydrogen, the system being provided with: a crankcase of the engine; an engine intake passage that sucks air into the engine; a crankcase intake passage that branches off from the engine intake passage and introduces air into the crankcase; a dilution air valve that is disposed in the crankcase intake passage and that opens and closes the crankcase intake passage; a compressor disposed upstream of a branch portion branching from the engine intake passage to the crankcase intake passage; a hydrogen sensor that detects a hydrogen concentration inside the crankcase; a crankcase exhaust passage that exhausts air inside the crankcase; and a control device that controls the opening and closing of the dilution air valve on the basis of the hydrogen concentration detected by the hydrogen sensor.

The application discloses a hydrogen engine crankcase hydrogen concentration control method, and relates to the field of hydrogen engines, which comprises the following steps: placing a hydrogen engine on a test bench to test, obtaining a target hydrogen concentration, an actually measured hydrogen concentration and a crankcase blow-by amount; calculating a target working condition supplementary air amount according to the target hydrogen concentration, the actually measured hydrogen concentration and the crankcase blow-by amount; generating a full working condition supplementary air amount database according to the target working condition supplementary air amount, based on the rotating speed and the load of different working conditions; obtaining the fresh air amount required to be supplemented by a current target working condition according to the full working condition supplementary air amount database; obtaining an intake air pressure, an intake air temperature and a crankcase pressure; combining the intake air pressure, the intake air temperature and the crankcase pressure to calculate a throttle opening degree; comparing the hydrogen concentration measured by a hydrogen concentration sensor according to the current target working condition with the target hydrogen concentration to obtain a hydrogen concentration deviation; generating a corrected fresh air amount; and performing closed-loop control on the actual crankcase hydrogen concentration by adjusting the throttle opening degree.

The invention provides a ventilation system of a supercharged engine. The first passage communicates the downstream intake part with the crankcase in order to ventilate the crankcase. A second passage communicates the upstream intake portion with the crankcase. The oil separator is provided in the second passage. A third passage communicates the downstream intake portion with the oil separator. The one-way valve restricts the flow of gas through the third passage from the oil separator toward the downstream intake portion.

The application relates to an engine crankcase oil-gas separation control method and system, which is used for optimizing the oil-gas separation efficiency of an engine crankcase oil-gas separation unit. The method comprises the following steps: determining an opening control parameter Delta P of a gravity one-way valve according to the pressure difference between the air flow pressure P2 of an outer cavity of the oil-gas separation unit and the air flow pressure P1 of an inner cavity of the oil-gas separation unit; acquiring the liquid surface pressure P of a dynamic oil liquid surface height H in an ascending process when the oil-gas separation unit is running; when P is smaller than Delta P, the gravity one-way valve is controlled to be closed; when P is larger than Delta P, the gravity one-way valve is controlled to be opened; in the opened state of the gravity one-way valve, the oil is discharged to make the dynamic oil liquid surface height H drop, and the state switching of the gravity one-way valve makes the dynamic oil liquid surface height H maintain small-amplitude fluctuation in a set interval. The application has the beneficial effects that the oil-gas separation system selection efficiency and control precision can be improved, and the one-time success rate and overall reliability of system development can be improved.

The utility model relates to the technical field of automobile accessories, in particular to an automobile valve chamber cover which comprises a cover body, an oil-gas separation cover and a protective buckle cover, an installation area is arranged on the cover body, and a backflow hole and an oil-gas outlet are formed in the installation area. The oil-gas separation cover is buckled on the mounting area and forms an oil-gas cavity and a waste gas transition cavity which are mutually independent, the oil-gas separation cover is provided with a waste gas discharge port and at least one oil-gas inlet, and the oil-gas inlet and the oil-gas outlet are both communicated with the oil-gas cavity; the protection buckle cover is buckled on the oil-gas separation cover, the backflow hole and the waste gas discharging opening are both communicated with the waste gas transition cavity, and a waste gas valve is arranged in the waste gas discharging opening. The automobile valve chamber cover adopts a split design and is convenient to manufacture and low in replacement cost.

The utility model discloses an anti-icing electric heating crankcase ventilation pipe, and relates to the technical field of ventilation pipes, the anti-icing electric heating crankcase ventilation pipe comprises a heating assembly, and the heating assembly is used for heating the ventilation pipe; the protection assembly is compounded on the outer side of the heating assembly, and the protection assembly is used for protecting the heating assembly; the heating assembly comprises a protection assembly and a stabilizing assembly, the stabilizing assembly is arranged on the outer side of the protection assembly and used for improving the stability of the protection assembly, the heating assembly comprises a ventilation pipe, a plurality of mounting grooves are formed in the center of the surface of one side of the ventilation pipe, and the multiple mounting grooves are each provided with an electric heating wire. According to the utility model, the ventilation pipe can be heated, and the stability of the ventilation pipe can be improved, so that the outer surface of the pipeline can be prevented from being damaged, and the service life of the pipeline can be prolonged.

To suppress generation of emulsion.SOLUTION: An engine 10 introducing air in an intake passage into a crankcase 15 so as to ventilate blow-by gas includes an air introduction passage which communicates the intake passage with the crankcase 15, a one-way valve 60 which is attached to the crankcase 15 and restricts the flow of gas in a direction from the crankcase 15 toward the intake passage through the air introduction passage, and a communication passage 73 which guides the air discharged from the one-way valve 60 into the crankcase 15 and is extended in a direction different from the air discharge direction of the one-way valve 60.SELECTED DRAWING: Figure 3

To provide a mounting structure for a valve capable of suppressing the occurrence of rattling in a mounting member for mounting the valve to an internal combustion engine.SOLUTION: The mounting structure includes a mounting member 25 separate from a valve, the mounting member 25 fixed to a separator 12 while covering the valve mounted to the separator 12 of the internal combustion engine, to prevent the removal of the valve from the separator 12, the mounting member 25 having a fixed hole 29 through which a resin protrusion 30 protruded from the separator 12 is inserted when covering the valve, the mounting member 25 fixed to the separator 12 by applying resin caulking to the protrusion 30 inserted through the fixed hole 29. On the inner face of the fixed hole 29, a first face 31 located corresponding to the outer face of the protrusion 30, and a second face 32 linked with the first face 31 and located to be farther away from the center of the fixed hole 29 than the first face 31 are formed.SELECTED DRAWING: Figure 9

The invention discloses an active crankcase negative pressure breathing device of an engine. The active crankcase negative pressure breathing device comprises a breathing device shell installed on a crankcase through a crankcase cover plate and an oil-gas separation device. A flow dividing type centrifugal filter device is installed in the respirator shell. The centrifugal filter device is driven by engine oil pressure of an engine to rotate, and the centrifugal filter device synchronously drives a fan device capable of pumping out mixed oil gas in a crankcase. Mixed oil gas discharged by the fan device can enter the oil-gas separation device to be decelerated, condensed and separated. Separated gas is discharged into the atmosphere, and condensed oil flows back into the crankcase; an oil supply hole channel used for providing press oil is formed in the bottom of the respirator shell, and an oil quantity control device capable of automatically adjusting the opening degree of an oil inlet according to the change of the pressure of the oil is installed in the oil supply hole channel. The device is simple in structure, safe and reliable, and the negative pressure in the crankcase can be always kept in a stable interval.

The present invention suppresses suction of gas from a suction passage. An internal combustion engine (10) for a vehicle is provided with a cylinder (23A), an intake passage (10A), a crank chamber (10Z), a suction passage (80Z), and an introduction passage (60Z). The intake passage (10A) introduces intake air into the cylinder (23A). The crankshaft chamber (10Z) accommodates a crankshaft (33). In addition, oil is stored in the crank chamber (10Z). The suction passage (80Z) sucks oil stored in the crank chamber (10Z). The introduction passage (60Z) introduces a portion of the intake air flowing through the intake passage (10A) into the crank chamber (10Z). The introduction passage (60Z) includes a main passage (63Z) and a plurality of outlet passages (64Z). The main passage (63Z) extends from the outside of the crank chamber (10Z) to the inside of the crank chamber (10Z). The outlet passage (64Z) discharges intake air flowing through the main passage (63Z). The outlet passage (64Z) extends from the main passage (63Z) toward the suction passage (80Z) when viewed from a direction along the vertical axis of the vehicle.

The utility model discloses a high-horsepower engine crankcase emission system, and relates to the field of engine crankcase emission, the high-horsepower engine crankcase emission system comprises an emission pipeline, a heating assembly and a temperature control module, the emission pipeline is communicated between a crankcase emission port and an engine tail gas treatment system, and the heating assembly is communicated with the temperature control module. The exhaust pipeline is arranged in the crankcase, the heating assembly is arranged on the exhaust pipeline, the heating assembly is used for heating the exhaust pipeline, and the temperature control module is used for controlling the heating assembly so that tail gas in the exhaust pipeline can be kept at the specified temperature. Tail gas generated by the crankcase is not directly discharged into the surrounding environment, the temperature of the discharging pipeline is kept above the dew point of the tail gas of the crankcase through the heating assembly and the temperature control module, and condensate water is prevented from being generated in the test process.

The inventio discloses a motor operation control method for an oil-gas separator to solve the problem that an existing oil-gas separator control strategy cannot minimize the operating speed under the precondition of satisfying operating requirements. The motor operation control method comprises: acquiring a plurality of groups of actual operating parameters output by a motor in a target operating state, establishing mapping relations according to the parameters, associating the mapping relations, and plotting a relation table; and acquiring a portion of operating parameters of the motor in a current operating state, searching for the mapping relations in the relation table to obtain other parameters, and adjusting corresponding parameter data with the obtained parameters as reference until the motor reaches the target operating state.

A closed crankcase ventilation system for removing blow-by gases, leaking from a combustion chamber, from a crankcase of an internal combustion engine. The system comprises a blow-by line extending between the crankcase and an air intake line of the internal combustion engine. When the engine is running, the air intake line provides a vacuum source for drawing blow-by gases from the crankcase through the blow-by line. A crankcase depression regulator is arranged in the blow-by line for regulating a level of vacuum inside the crankcase. At least one pressure sensor is arranged for measuring a pressure in the blow-by line relative to atmospheric pressure. A control unit is arranged for detecting leakages in the blow-by line by performing a diagnostic test based on a pressure measurement signal from a single pressure sensor.

The utility model relates to a connecting structure of a PCV box and a rubber tube, which comprises a first interface and a second interface which are respectively formed on the PCV box and the rubber tube, the first interface is sleeved with the second interface, and the connecting structure is characterized in that a first clamping structure is formed on the outer surface of the PCV box at a position opposite to the rubber tube; a first clamping structure is formed on the outer periphery of the PVC box, a second clamping structure corresponding to the first clamping structure is formed on the outer periphery of the rubber pipe, the PVC box and the rubber pipe are connected in a clamping mode through the first clamping structure and the second clamping structure, an annular sealing rib is arranged on the outer periphery of the first connector, and the first connector is sleeved with the second connector. And the inner circumferential surface of the sealing ring is in interference fit with the sealing rib. The first connector on the PCV box is connected with the second connector on the rubber pipe in a sleeved mode, the sleeved position is sealed and free of leakage through the sealing rib, meanwhile, the PCV box and the rubber pipe are connected in a clamped mode through the first clamping structure and the second clamping structure, and it is guaranteed that the PCV box and the rubber pipe cannot be disengaged after being assembled.

The invention discloses a crankcase ventilation system, a control method and a vehicle, relates to the technical field of engines, and can reduce engine oil emulsification and improve engine reliability. The crankcase ventilation system comprises a crankcase, the crankcase comprises a crankshaft cavity and an oil storage cavity, and the crankshaft cavity is communicated between an engine air cylinder and the oil storage cavity; the air inlet channel is provided with an air inlet manifold, and the air outlet end of the air inlet manifold communicates with an air inlet valve of the engine. The air inlet end of the first exhaust channel is communicated with the crankshaft cavity, the air outlet end of the first exhaust channel comprises a first sub-end and a second sub-end, and the first sub-end is communicated with the first air inlet end of the air inlet manifold; the air inlet end of the second exhaust channel is communicated with the second sub-end, the air outlet end of the second exhaust channel is communicated with the second air inlet end of the air inlet manifold, the first exhaust channel is provided with a first one-way valve, and the second exhaust channel is provided with a second one-way valve.

The utility model relates to the field of engine parts, in particular to a degassing device for an engine oil cooler of a high-horsepower engine, which comprises an engine oil cooler mounted on a cylinder body, a water pump is mounted at the engine oil cooler, and the cylinder body is provided with a water inlet and a water outlet. A water inlet and a water outlet are formed in the cylinder body, a water inlet pipe and a water outlet pipe are installed on the water inlet and the water outlet respectively, a water inlet header pipe is arranged on the cylinder cover, the cylinder body is communicated with the water inlet header pipe through a degassing pipeline, and a degassing connector is installed on the water inlet header pipe. If the water pump does not build the pressure and the pressure is insufficient, the boiling point of the cooling liquid is reduced, the cooling liquid is easy to boil, more bubbles are generated, vicious circle is formed, local high temperature is possibly caused, and engine parts are damaged.

With its simple structure, it reliably prevents or suppresses the rise in internal pressure of the oil tank. [Solution] The system includes an on / off valve 15 provided between the oil tank 3 and a gas receiving section 10 that receives blow-by gas without leaking it to the outside, and a controller 19 that controls the on / off valve 15. The controller 19 includes a low-pressure determination unit that determines that the pressure inside the oil tank 3 is lower than a predetermined first reference pressure, a determination unit that determines that a predetermined condition other than the pressure inside the oil tank being lower than the first reference pressure has been met, and an opening control unit that opens the on / off valve 15 when the low-pressure determination unit determines that the pressure inside the oil tank is lower than the first reference pressure, or when the determination unit determines that a predetermined condition has been met.

The application discloses a method for controlling the concentration of combustion gas in a crankcase, a device for controlling the concentration of combustion gas in a crankcase, a vehicle and a computer storage medium, wherein the method for controlling the concentration of combustion gas in a crankcase is applied to a vehicle, and the method comprises the following steps: obtaining the current operating condition of an engine and the concentration of hydrogen in the crankcase; adjusting the rotating speed of a centrifugal oil-gas separator according to the operating condition; and when the concentration of hydrogen increases, performing a first step, wherein the first step comprises reducing the torque of the engine. The method for controlling the concentration of combustion gas in a crankcase can keep the volume concentration of hydrogen in the crankcase at a low level.