CN1015019B - Improvement of two-stroke internal combustion engine and operation method thereof - Google Patents
Improvement of two-stroke internal combustion engine and operation method thereofInfo
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- CN1015019B CN1015019B CN87103277A CN87103277A CN1015019B CN 1015019 B CN1015019 B CN 1015019B CN 87103277 A CN87103277 A CN 87103277A CN 87103277 A CN87103277 A CN 87103277A CN 1015019 B CN1015019 B CN 1015019B
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- motor
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- working room
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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Abstract
The present invention relates to the improvement and an operation method thereof for a two-stroke internal combustion engine. The internal combustion engine cyclically works according to two strokes. The present invention has the characteristic that an air inlet timing element and an air exhaust timing element are air valves (7, 9); a control mechanism reacts on parameters of rotation speed of the internal combustion engine, fuel consumption, pressurizing values, air inlet pressure differential and air exhaust pressure differential, and thus, the opening positions and the closing positions of the air valves (7, 9) are changed, which enables sufficient fresh air to enter a working chamber under the disadvantageous working condition; when the volume of the working chamber is increased, the air valves are opened, and the fresh air enters the working chamber.
Description
What the present invention relates to is internal-combustion engine, and this machine comprises the working room (firing chamber) of a variable volume that is limited by piston at least, and has a suction port and a relief opening at least.This machine carries out work by two strokes.
The motor that the present invention relates to best (but might not require) is to increase with turbosupercharger.Pressurized machine is made up of two-part: a turbine and a mechanical with it compressor that links to each other that is driven by engine exhaust, the outlet of this compressor communicates with the suction port of each working room.
As everyone knows, an internal-combustion engine is made up of the firing chamber of at least one variable volume, i.e. firing chamber that limits by a live animal (as piston) and a fixed block (as cylinder), and this internal combustion engine always has two tangible stages, that is:
A closing stage because timing mechanism makes inlet and outlet be in closed condition simultaneously, isolates firing chamber and inlet and exhaust system in this stage.
The open phase of a ventilation, in this stage, the firing chamber communicates with air inlet and/or vent systems.
In all these class motors, this open phase all has one period stage of removing pressure in each firing chamber, and this draining period is last at closing stage and expansion stroke, only vent systems is opened by exhaust timing element, and the firing chamber is communicated with it.This draining period usually is known as " exhaust impact " or " exhaust pulses " in English.Make internal pressure of combustion chamber be much higher than the pressure (its ratio is between 2 or 3) in the vent systems owing to produce hot gas by burning, produce in the meantime and expand, can reach velocity of sound during beginning and be subsonic speed afterwards, the most of gas in this process in the firing chamber all is admitted to vent systems.
In four stroke engine, after draining period, have at least a part of remaining combustion gas to be shifted onto in the exhaust system and go by piston, then afterwards swept volume increase stage is inhaled into fresh air.On the other hand, in the motor of one two stroke, the waste gas that exhaust cycle remains in the working room later then is at scavenging period, when promptly the intake and exhaust element is opened simultaneously, is evicted from the firing chamber by the fresh air of high-speed motion.The significant degree of scavenging is the efficient of two-cycle engine and a determinant factor of performance.The scavenging system that various recommendations have been arranged in this respect particularly uses valve as the inlet and outlet element in two-cycle engine.
Yet, make scavenging obtain remarkable result, the pressure of upstream, working room (being gas handling system) which kind of motor generally speaking all will be higher than the pressure of downstream one side (being vent systems) in scavenging process.Therefore, all two-cycle engines even to this day, in above-mentioned scavenging process, all need a kind of pressurization means with keep this pressure difference average out on the occasion of.
The method of this generation pressure, or adopt the piston that moves as the double-action part, for example match with empty chamber in its underpart, or match with the main shaft casing, and link to each other with suitable delay cell, guaranteeing the precompression of air before entering the working room, or adopt an auxiliary regulator that is connected with spindle machine, such as impeller or compressor or ROOTS formula compressor, or can't help main shaft drives and with electronic.
From economic point of view, adopt these distinct methods that produces pressure, increase engine accessory power rating, influence size of engine and energy consumption, thereby shortcoming is all arranged.
In the supercharging two-cycle engine, motor is under the high power work state, and upstream and downstream two ends, the necessary firing chamber of scavenging positive pressure difference can be guaranteed by turbosupercharger naturally in the scavenging process.Really, when compressor during with the work of enough pressure ratio, the expansion ratio of the turbine that the stabilized driving turbosupercharger is required is always smaller because this moment pressurized machine total efficiency and can be higher in the delivery temperature in outlet port, working room.Therefore, concerning the turbosupercharger in modern times, if its total efficiency is 60%, its turbine end intake temperature is 600 ℃, and pressure is 4 crust, and the pressurized machine end then can increase to 20 ℃ air pressure 5 crust, and the working room just obtains the positive pressure difference of 1 crust naturally like this.
Yet when these supercharging two-cycle engines during in low-power operation, the gas enthalpy in outlet port, working room is not enough to guarantee that charging turbine reaches that to make above-mentioned pressure difference be positive rotating speed.The result is if there is not supplementary equipment, because this reverse pressure difference can stop fresh air to enter the working room, and to make engine stoping operation.Equally, wanting to pilot engine also can be extremely difficult.
Perhaps, these supplementary equipment are that types of generation pressure above-mentioned, perhaps are a kind of turbosupercharger that can be independent of motor, and can be with the speed running that prevents in the upstream, working room, the two ends, downstream produce reverse pressure reduction.For example, be communicated with the import of turbine with of the outlet of a by-pass conduit, and link to each other, drop under the predetermined threshold with the rotating speed that prevents turbosupercharger with a speed regulator again with an auxiliary combustion chamber with pressurized machine.The another kind of selection can be that this turbine can be imported the liquid of pressure, such as a kind of Pelton formula water turbine device the additional turbine of turbosupercharger.
Yet these known supplementary equipment are all complicated, and cost is also high, and when using, consequently oil consumption increases.
Therefore one object of the present invention just provides a kind of use turbosupercharger, and does not need the motor of outside scavenging arrangement when starting and during low-power operation.
Another object of the present invention then is when there not being an above-mentioned optional equipment two stroke engine, and is special but be not only that supercharged engine guarantees that fresh air enters each working room of two-cycle engine in a kind of natural mode when low-power operation and starting.
Another object of the present invention is in order to help sucking fresh air, utilizes or is the gas energy of part utilization in the outlet port, working room at least.
Another object of the present invention is as using turbosupercharger, to be increased in the gas energy in each outlet port, working room when exhaust timing element is opened, to impel the acceleration of turbocharger rotor.
Another object of the present invention is to improve the torque characteristic curve of motor.The present invention proposes a kind of two-cycle engine, has the working room of at least one variable-volume, and its working room's volume is to be limited by the piston that is arranged in a no horizontal gas port cylinder.This motor is preferably turbocharger supercharged by (but being not limited only to), and this turbosupercharger exhaust gas turbine import links to each other with the outlet of working room, and the air outlet slit of its pressurized machine communicates with the suction port of working room.Pressurized machine is driven by exhaust gas turbine machinery, and the suction port of engine operation chamber and relief opening all have the inlet and outlet door with the action of engine crankshaft rotational synchronization.Be characterized in, above-mentioned inlet and outlet door is driven by control gear, control gear can be according to the variation of at least one parameter in the engine operation, and the pairing engine crankshaft corner of change inlet and exhaust valve opening and closing position, when starting and during the low-power running, above-mentioned control gear is reacted to the running parameter variation of above-mentioned motor, and intake valve is opened in advance with respect to the normal operation operating mode, keeps intake valve than 20 ° of the late at least unlatchings of exhaust valve simultaneously.Guarantee that sufficient air enters the working room.
By the present invention, the device of control inlet and outlet door allows in the large crankshaft angle range its angular orientation that begins to open and close is being adjusted very much.
Therefore the field of the invention is not included in the sort of fixed timing element of being made up of the gas port that is located on the fixed air casing wall and periodically expose when piston that can see in most of two-cycle engines in running.Concerning fixed timing element, the angular orientation that gas port opens or closes with respect to the piston motion position is once determine just immutable, and with respect to piston position (the being called as lower dead center) symmetry of corresponding working room maximum volume, above-mentioned suction port guarantees working room and outside communication.
Arrange in method described in the F.P. by on January 15th, 1976 as valve, then more superior.
In the present invention, the engine running parameter meaning is the detectable parameter of and at least desirable two values relevant with engine running.One of them value is corresponding to the normal operation operating mode of motor.The upstream, firing chamber is that air inlet side and downstream are that the pressure difference of exhaust side just remains during this running operating mode.Be enough to guarantee the normal operation of a conventional two-cycle engine.Another value another operating mode of corresponding motor then, promptly above-mentioned at this moment pressure difference is big inadequately or for negative value or there is not pressure difference, just the situation of engine stoping operation.
This parameter can be:
The boost pressure value of supercharging two-cycle engine.
Every circulation enters the amount of fuel of working room.
The engine crankshaft rotating speed.
Temperature in the gas exhaust manifold
The effective value of inlet and outlet pressure difference, or preferably the direct pressure in working room's upstream side and downstream side is poor.
Control gear can be a various forms, the above-mentioned parameter that is recorded by sensor made a response, and the action of control inlet and outlet door.Such as them can be mechanical, by resembling Transmitted chains such as camshaft directly by crank-driven, just need provide the controlling device of machinery or alternate manner in this case, so that revise the CAP of inlet and exhaust valve opening and closing.
Control gear above-mentioned also can be a motor, fluid power or pneumatic type, and with the rotational synchronization of engine crankshaft, the controlling device that the response above-mentioned parameter changes also allows the CAP that the inlet and outlet door is opened and closed is revised.
Therefore, based on the present invention, two kinds of journey motors (can be that supercharging is not supercharging yet) that motor can various form known are worked in the scope that runs well.Simultaneously, if can adjust to guarantee or the replacement scavenging its operation in the outer work of normal operating limit.
This is to obtain with the intake stroke that mainly utilizes each swept volume of a single chamber constantly to increase by changing inlet and exhaust valve opening and closing angular orientation with corresponding mode.
For reaching this purpose, being open in the circulation of intake valve will obviously shift to an earlier date at least, for example, arrives near the middle moment of working room corresponding to piston motion, and corresponding correction is also wanted in the timing of exhaust valve.
Further, exhaust can increase the exhaust energy that occurs with higher temperature and pressure form in advance in circulation.In the turbine pressurizing two-stroke motor, the turbine itself that drives pressurized machine is by exhaust gas driven, and in this case, vent systems preferably directly is connected between exhaust valve and turbine.Have now found that when rotating speed is low exhaust pulses can make the turbosupercharger generation slowly run, this can not produce the supercharging of engine air, but can cause working room's inner air flow.This is enough to discharging gas of combustion, and can allow fresh air replace.
Curve outlet pipe and feed gas exhaust manifold with conventional method and just can guarantee this direct-connected connecing.Flow area does not axially produce any resistance to exhaust pulses with the gas exhaust manifold that high speed, big flow adapt at manifold, and manifold communicates with turbine, does not have shunt in the middle of it.
In one particular embodiment of the present invention, the CAP that inlet and exhaust valve is opened and closed is adjusted into and makes inlet and exhaust valve can not be in the state of opening simultaneously basically simultaneously.
In the another embodiment of the present invention, the inlet and outlet door can have opening state simultaneously, for speed limit or prevent that waste gas in the vent systems from backflowing in the working room, just need provide a kind of one-way throttle device.
In above-mentioned second example of the present invention, can in air outlet flue, use one-way valve or other mechanical safety check.The inertia effect of gas column in the time of also can utilizing waste gas to the pipeline of gas exhaust manifold, to move from connecting the air outlet, working room.Or, during best three above working rooms, utilize the waste gas pulse of coming out to another injection effect that is produced in the exhaust of the working room of scavenging period from a working room as a plurality of.
When utilizing the waste gas inertial time, in vent systems, particularly in the connecting tube of working room's relief opening and gas exhaust manifold, preferably can be made up of sufficiently long fixedly outlet pipe the above-mentioned one-way flow device of the device of one-way flow, its direction that exports exhaust air flow in best and the gas exhaust manifold is arranged in the same way.
Also can utilize the injection effect that produces by the waste gas pulse, particularly when the working room surpasses three.For being connected of the waste gas outlet that guarantees the working room and gas exhaust manifold, the shape of connecting tube should be the convergent-divergent tubular type, its outlet should be arranged to gas exhaust manifold in air-flow flow to identical, preferably and manifold concentric.
In a back situation, gas exhaust manifold can have an enough little uniform section passage, under the condition that runs well, will surpass 0.4 Mach number in above-mentioned outlet pipe middle and lower reaches end airspeed like this.The gas exhaust manifold outlet port links to each other with the exhaust gas turbine import of the turbosupercharger of supercharged engine, by a diffuser flow velocity is dropped to below 0.4 Mach number, the another kind of selection, the outlet of gas exhaust manifold can directly link to each other with the turbine inlet of turbosupercharger, and the shunting volute of turbosupercharger is arranged to such an extent that the speed of gas exhaust manifold outlet port and turbine rotor inlet gas can not reduced.
The present invention also provides the method for operating of two-cycle engine defined above.
First kind of method of operating has following feature:
A) when the top parameter value of carrying turned round working condition corresponding to the normal or nominal of motor, motor just turned round in following two kinds of known journey modes:
Compression-burning-expansion stage when inlet and outlet are all closed;
When having only exhaust valve to open, at the exhaust phase that expands latter stage;
Scavenging period when intake valve and exhaust valve are opened simultaneously, in the meantime, under each upright action of pressure of every working room, have at least a part of waste gas to be replaced by fresh air;
B) on the other hand, when operating parameters value representation motor is in the working condition that can not or be unsuitable for turning round, the angular orientation of valve opening to be reached the position of maximum volume with respect to each working room and shift to an earlier date, make engine aspirating system and working room like this in the process that swept volume of a single chamber increases, or in this process, interconnect basically.Can assign a work connecting tube between chamber and the gas exhaust manifold particularly when stage that the inlet and outlet door is opened simultaneously, occurs to stop from the phenomenons of gas exhaust manifold direction to a large amount of anti-streams in working room.
When parameter surpassed a threshold value of reserving in advance, the CAP of inlet and exhaust valve action just obtained suddenly revising, and what can select mode then is the threshold value of a plurality of continuing property to be set, with corresponding with a plurality of sudden change correction values of valve position.
The another kind of selection is that above-mentioned angular orientation is revised in advance by the continuity or the quasi-continuity variation of parameter above-mentioned.This parameter is by continually varying between optimum condition and the worst operating mode.
Note that and now known that such two stroke engine is also arranged, wherein only air inlet or exhaust are that valve by a can regulate timing carries out, and its exhaust or air inlet then are to obtain by the fixed gas port of piston through being exposed later.
In contrast, IO Intake Valve Opens can shift to an earlier date among the present invention, and opens immediately after exhaust valve is opened, and can temporarily obtain the four-stroke effect that is caused by IO Intake Valve Opens.For band fixedly the motor of the suction port of enable possition (as U, S ,-A-2,097,883, remove Fig. 6) this effect is just impossible.And can shift to an earlier date really for having opening of its air inlet, but be not the motor of following the exhauxt valve opens suction port (as U, S-A-2,097,883, Fig. 6), this effect also is impossible.
Or rather, according to the present invention, under the normal working of engine condition, motor useful (compression) stroke is 50% of each stroke of piston at least.When starting or the running of small-power operating mode, aspirating stroke is 50% of combined stroke at least.And compression stroke can be 100% of this stroke, and row, IO Intake Valve Opens stagger angle for more than or equal to 20 ° (engine crankshaft corners).
For the existing two stroke engine of bringing gas port and variable timing exhaust valve into,, just can not increase aspirating stroke because suction port is fixed.And by the same token, compression stroke is the increase of part only, promptly can not reach 100%.
For the existing two stroke engine that the intake valve of relief opening and adjustable timing is arranged, might increase aspirating stroke but sacrificed inlet and outlet and opened at interval, therefore exhaust will be discharged in the intake duct and go, the result makes engine misses, furtherly, because relief opening is fixed, compression stroke can not reach 100%.
Further, the someone proposes to make motor to change jobs by two strokes and four-stroke wheel, does not promptly have continuously between two kinds of patterns or variation gradually (seeing JP-A-58,152179)
The present invention also relates to the method for the such motor of starting, in the method, when starting, motor is pressed the operation of one of said process, is characterized in that when motor is boosting type turbosupercharger had just been got up before engine start.
Other advantage of the present invention and characteristic will be clearly from following illustration, and illustration is with nonrestrictive, and with reference drawing.These figure are:
Fig. 1 represents the working room's schematic representation according to two-cycle engine of the present invention;
Fig. 2 represents the angle figure that two kinds of Cheng Xunhuan inlet and outlet of this motor door is opened and closed.
Fig. 3 represents that an example according to the present invention is when the diagram of motor when low-power turns round.
Fig. 4 represents according to another example motor diagram when low-power turns round of the present invention.
Fig. 5 represents that is the view by Fig. 4 operating mode running designed engines.
Fig. 6 represents the view of the motor that another designs for turning round by Fig. 4 operating mode.
At first see Fig. 1 and Fig. 2;
The motor that the present invention will be referred to is a motor that one or more working rooms are arranged, as F.P. the 2nd, 338, described in No. 385.This working room shown in Figure 1 forms by following: 1 motion parts, i.e. piston 1 of Hua Donging and connecting rod 2, with a standing part, be cylinder 3 and cylinder cap thereon 4, the latter has an intake duct 5 and an air outlet flue 6, intake duct is cooperated with valve seat 8 by intake valve 7 and the energy opening and closing, and exhaust side then has exhaust valve 9 and valve seat 10 to match.Therefore do not have gas port on cylinder 3 casing walls, valve seat 8 and 10 is set in the cylinder cap 4.
Other part of motor, as bent axle, camshaft, rocking arm will be not described in detail, because they all are conventional parts, valve lift and size thereof are also arranged by optimum value, as above-mentioned F.P. the 2nd, the same in 338, No. 385, so that under the normal operation condition, obtained performance as far as possible.
Fig. 2 represents the known operating mode of this motor, and this figure is for clockwise rotating, and its starting point is lower dead center (BDC), and the angular orientation is as follows:
(EO)-60 ° left by exhaust valve
Exhaust valve closes (EC)+100 °
IVO Inlet Valve Open (IO)-30 °
Intake valve closes (IC)+100 °
So as seen,, opening and intake valve is still closed 30 ° from the descending 120 ° of exhaust valves of top dead center, is exhaust cycle in these 30 °.After intake valve was opened, 130 ° the scavenging period that exhaust cycle comes with regard to becoming subsequently,, during this period, combustion gas was under the aerodynamic effect of working room's intake duct 5 and air outlet flue 6 both sides positive pressure differences and upgrade.After this dwell period continues 200 °, and in this example by asymmetric mode to be divided into corresponding volume compression ratio be 8/1 80 ° compression stroke with cubical expansion than being 12.9/1 120 ° the burning-expansion stroke that conforms to.
This extremely asymmetric circulation can obtain higher specific power and high efficiency by known method.
This class timing diagram can be accomplished with known method, and particularly under the camshaft with the bent axle mechanical connection helped, camshaft directly or indirectly cooperated with valve and returning device thereof.The co-operation of camshaft and valve can be that mechanical (as push rod, rocking arm etc.) also available as hydraulicdriven mode obtains.
This also can be obtained with other control gear that is easy to change the angular orientation, as with hydraulic pressure or baroswitch or magnetic switch.
According to the present invention, these control gear are all arranged to such an extent that can make the angular orientation of inlet and outlet door obtain bigger variation in engine operation process.
For example, camshaft with can comprise variable adjustment device (as the hydraulic regulation in gap, or the displacement of rocking arm axis) being connected of each valve.
Perhaps cam and camshaft, perhaps cam can change by known method with being connected also of engine crankshaft.
Also can use the cam of two kinds of molded lines, and can in operation process, change a kind of molded lines into another kind of molded lines by changing camshaft.
Directly with hydraulic pressure, air pressure or magnetic switch control the time, the angular orientation of valve switch can change with auxiliary device, for example uses engine crankshaft position sensor.
See the 3rd figure now, this figure relates to enforcement first method of the present invention, is described below:
According to the present invention, said motor in the example is as long as a parameter of its running is higher than certain threshold value just by Fig. 2 two-stroke cycle work.This parameter can be the rotating speed of bent axle.When this rotating speed dropped under the threshold value, according to the present invention, the device of control valve immediately can be according to the angular orientation of Fig. 3 correction inlet and outlet door opening and closing.In the latter, engine crankshaft corner is as follows:
Exhaust valve leaves (EO) :-120 °
Exhaust valve closes (EC) :-90 °
IVO Inlet Valve Open (IO) :-90 °
Intake valve closes (IC) :+20 °
Like this, visible exhauxt valve opens has shifted to an earlier date 60 ° to the top dead center direction, and only continues 30 °, and during this period, in the exhaust cycle that causes that expands after exhaust valve 9 unlatchings, combustion gas is partly discharged with the form of blast.At this 30 ° last, exhaust valve 9 cuts out.
Under any circumstance, the differential seat angle that IVO Inlet Valve Open and exhaust valve are opened (crank angle) is the limit value greater than 20 ° that stipulate previously, and differential seat angle is 30 ° in this example.
Therefore, scavenging process is deflated door 9 and closes simultaneously the processes that inhale fresh air of the IO Intake Valve Opens that occurs and replace and be eliminated, this breathing process continues 110 °, just satisfied from volume and to be half condition of maximum functional chamber volume, say that in quality the ratio that has reached fresh air is 2/3, this is enough to oil firing that idling operation is infeeded.
Behind the IC Intake Valve Closes, be exactly compression stage, during near top dead center, burning, circulation restarts.
Because the inlet and outlet door will never be opened simultaneously, the pressure in the gas exhaust manifold is just inoperative.Motor by this method is designed although be not boosting type, can start or steady running under the idling condition equally.
Moreover it should be noted that compression stroke begins near lower dead center, the result is that the volume compression ratio can reach 15.6/1(rather than 8/1), even if like this under the diesel engine normal pressure air inlet also can guarantee the fuel-air mixture spontaneous combustion.
In first above-mentioned example, if use fluid power valve or solenoid valve directly to control valve, the timing diagram among Fig. 3 will be easy to realize.Really, when the rotating speed of bent axle is lower than above-mentioned threshold value, also might obtain valve, particularly the high angular velocity opening and closing of exhaust valve 9.When use hydraulic element between valve and hydrovalve, the speed of this switch also can further improve.These links that link to each other with known hydraulic pressure advance/retard mechanism allow to shorten or reduce the lift of valve.
If use conventional valve control piece (camshaft matches with elastic controller), the timing diagram of Fig. 3 sometimes may difficult realization, when particularly rotating speed is higher, because close very steep that the cam dropping section of valve just has to design.
At motor the situation of a camshaft is arranged, example can make an explanation referring to Fig. 4 referring to Fig. 4 preferably.
In this example, in the time of under rotating speed drops to the fixed threshold value, camshaft is promptly counterclockwise setovered 60 ° backward, and the timing diagram that obtains like this is:
Exhaust valve leaves (EO) :-120 °
Exhaust valve closes (EC) :+40 °
IVO Inlet Valve Open (IO) :-90 °
Intake valve closes (IC) :+40 °
In Fig. 3 example, inlet and outlet opening angle difference is 30 °, yet with shown in Figure 3 opposite, is exactly the mixing period that IO Intake Valve Opens begins behind the exhaust phase, and the inlet and outlet door is opened simultaneously during this period.
During descent of piston, if the pressure in the gas exhaust manifold is higher than suction pressure, will influence stable idle of motor, flow backwards for fear of the waste gas that comes from gas exhaust manifold, in this example, in the exhaust valve downstream side pipeline that connects working room and gas exhaust manifold, all arranged such as devices such as exhaust check valves.
These valves can replace with any suitable device, such as, in above-mentioned pipeline, establish the aerodynamic force diode.
In another example of the present invention, inlet and outlet door timing diagram is the same with Fig. 4, and promptly when descent of piston, it has such stage that the inlet and outlet door is opened simultaneously.
First of above-mentioned example is chosen as, and utilize to connect the inertia effect of gas column that is kept in motion in the air outlet flue of gas exhaust manifold of working room's exhaust outlet, or is used in downward stroke exhaust valve in latter stage 9 and opens the exhaust pulses that produces and avoid flowing backwards.
This effect, just well-known triumphant younger brother Nahsi (Kadenacy) effect requires outlet pipe (on diameter and length) that special layout is arranged, and reaches optimum efficiency.
If outlet pipe 11 is arranged to such an extent that to make the direction of direction that exhaust flows out and gas exhaust manifold 12 are (see figure 5)s in a straight line, although like this when low speed, triumphant younger brother Nahsi effect deficiency, can obtain equally making exhaust with the formal freedom ground of pulse by gas exhaust manifold 12.Under the situation of the turbine 29 that has turbosupercharger 28-29 as shown in Figure 6 behind the gas exhaust manifold of motor, if before not being placed on turbine such as change pipe, collector ring or the such bar of shunt, then exhaust is impacted is enough to by Pierre's (Pelton) effect of pausing turbosupercharger be rotated, this enters working room 3 with regard to guaranteeing the virgin gas in suction tude 27, has guaranteed reliably and flexibly to turn round when motor particularly starts under most severe condition.
See that from Fig. 5 according to following composition on the motor of the present invention: 14, three working rooms of rotating bent axle or cylinder 3 are arranged, and it is by air-strainer 16 air inlets in intake manifold 15 and the gas handling system in cylinder body 13.Intake valve 17 and exhaust valve 18 are driven by control gear 21 by camshaft 19,20.This motor also comprises: bent axle 14 speed probes 22, and air inlet pressure transducer 23, fuel introduction device 25 is surveyed first circulation and is entered the sensor 24 of working room's 3 amount of fuel, also exhaust temperature sensor 34 can be arranged.Simple or complicated parameter value that electronic equipment 26 receiving sensors 22,23,24 and 34 of control set for adjusting 21 are measured and control gear 21 are regulated normal two stroke operating modes or are compared by the threshold value of the correction operating mode of invention, and react in view of the above.
During another of this example of the present invention selected: when scavenging, utilize from a working room or injection effect that air-flow pulse that cylinder 3 comes out produces is removed waste gas another cylinder.The quantity of considering the time service chamber that angle continues in this process is greater than 3.
Fig. 6 represents such one motivation that starts exactly, and wherein all and Fig. 5 components identical all indicate except that specializing identical number.
Shown in motor constitute by five working rooms 5.The turbine 29 of exhaust-driven supercharger, air is delivered to intake manifold 27 by the compressor in the turbosupercharger 28 with certain pressure, is sent to the working room again, and pressurized air is at first by 30 coolings of an air-cooler.Vent systems 31 has been used the fuel gas injection effect.
This injection effect can obtain in the method shown in 2478736 from F.P. 2378178,2415200.
Layout shown in Figure 6 needs following structural feature:
The A-working room exports to gas exhaust manifold 31 and has only the very little utmost point nipple 32 of volume, these pipe 32 or reducing pipe or convergent-divergent pipes, and its outlet is consistent with the flow direction of gas exhaust manifold.
The pipe 32 very little volumes and the restriction of channel cross-section help to recover the energy that the exhaust incipient stage exists very much in the working room.Pressure when exhaust valve is opened in the air outlet flue improves rapidly, and near the pressure in the firing chamber, the energy loss of producing owing to the aditus laryngis effect in the time of so just can significantly reducing waste gas by above-mentioned exhaust valve.
Like this, the useful power that exists in the working room when expanding end can be held to greatest extent.
The layout that the air-flow acceleration of reducing pipe 32 and its in-line arrangement tracheae flow to makes this potential energy be converted to the promotion kinetic energy that mobile gas column quickens in above-mentioned manifold 31 effectively.
B-converges the waste gas of discharging from several working rooms in a gas exhaust manifold 31, compare gas exhaust manifold diameter less (have only one medium-sized little) with piston
The size of manifold can be expressed as follows:
S
e＝（n·S
p）×V
p/V
e×P
e/P
5×α
Wherein:
S
eThe sectional area of=gas exhaust manifold
S
p=each piston horizontal table area
The n=number of pistons
NS
p=with cylinder that same gas exhaust manifold communicates in whole surface areas of pistons.
V
p=mean piston speed
V
e=in the exhaust velocity of gas exhaust manifold downstream end.
P '=density of the induced air
P
5=exhaust density
The flow system of a=motor (between 0.5 to 1.2)
Mach 2 ship at gas exhaust manifold downstream end exhaust flow velocity:
m＝V
eα/
5
A wherein
5=1.33 * 287 * T
5
T
5=delivery temperature ° K
If T
5=873 ° K(600 ℃), a
5=577m/s,
M=0.3, and V
e=177m/s
The adjusting of the ignition order of C-pair of each cylinder that links to each other with same gas exhaust manifold should make a certain amount of injection order of coming out from each working room suitable, and make it even as far as possible, makes the exhaust of a cylinder can not disturb the exhaust of another cylinder.
The connecting tube 33 of D-between gas exhaust manifold downstream (along flow direction of exhaust gases) and turbine 29 inlets is brief as much as possible, to avoid causing that owing to the variation (bend pipe or the abrupt change of cross-section) of resistance or passage the high velocity air total pressure descends as far as possible.For example, when Mach 2 ship 0.7, cause that by flow resistance the stream pressure decline on the unit length should be manifold diameter 1%.
E-selects inserting member: add a diffuser between the downstream of gas exhaust manifold and turbine inlet, air-flow velocity is dropped to 0.25 Mach number.
But consider that air-flow can be accelerated to Mach number 1(again usually in the retaining ring of a band nozzle that is called the branch compression ring before entering turbine), clearly preferably can cancelling slows down in diffuser quickens in minute compression ring again, and replaces E with following method:
E '-exhaust enters the housing designs at turbine place, should guarantee that before air-flow entered turboexpander, its speed remained unchanged substantially.
It should be noted: when being in the low-power operating mode by motor of the present invention, the opening in advance of exhaust valve-described 60 ° in advance as previous examples, promptly the 120 ° of exhaust valves before bottom dead center that finish at the expansion stroke away from piston are opened ,-following many advantages are arranged:
Because the pressure and temperature when exhaust valve is opened in the working room and the quality of exhaust are all higher, then the exhaust impulse ratio is bigger: the driving of charging turbine and acceleration will improve greatly, if particularly vent systems is second example arrangement describing just now by the present invention.
In like manner, motor small-power when running, the improving of two stroke engine from the scavenging meeting.
To given engine output shaft power, the minimizing of expansion stroke means that oil consumption increases, so the temperature of waste gas when leaving the working room also increase, and this factor also helps charging turbine and drives.
When minimum speed, can spray or the inertia effect utilizes exhaust to impact the pulse that produces when not enough at the straight-through tube 33 between straight line type gas exhaust manifold and turbine 29 imports, be enough to obtain good scavenging with the air ventilation of the working room that guarantees to produce by turbosupercharger.
The present invention can also have many modifications certainly, and the various inlet and outlet timing diagrams that mention previously are main to be mentioned with mode for example, and within the scope of the present invention, these figure also can have other variation.
Claims (27)
1, a kind of two-cycle engine, working room (3) with at least one variable-volume, its working room's volume is that the piston by the cylinder that is arranged in a no horizontal gas port limits, the air inlet of working room and exhaust are by controlling with the intake valve (7) and the exhaust valve (9) of the action of engine crankshaft rotational synchronization, the feature of this motor is: inlet and exhaust valve (7,9) is driven by control gear, and this control gear can change the unlatching of valve according to the variation of at least one engine running parameter and cut out pairing engine crankshaft corner; Above-mentioned control gear is reacted to the above-mentioned motor-driven variation of changing a job the condition parameter of starting, when starting and small-power running, the relative nominal situation of intake valve is opened in advance, and keep its unlatching to be later than exhauxt valve opens constantly, so that under various operating modes, obtain sufficient fresh air, to guarantee engine start and low-speed running in each working room.
2, according to the motor of claim 1, characteristics are when starting and low-power operation, and IO Intake Valve Opens point is 20 ° with the crank angle difference of exhauxt valve opens point at least.
3, according to the motor of claim 2, characteristics are: by turbocharger supercharged, the suction port of its turbine links to each other with the vent systems of working room, and the outlet of the pressurized machine that is driven by turbomachinery is connected with the suction port of working.
4, according to the motor of claim 1, wherein have sniffer, to measure the following parameter relevant with engine operating condition:
The boost pressure of supercharging two stroke engine;
Or every circulation enters the amount of fuel of working room;
Or engine crankshaft rotating speed;
Or delivery temperature;
Or the effective value of inlet and outlet pressure difference.
5, according to the motor of claim 1, characteristics are that wherein control gear is mechanical, are directly driven by engine crankshaft by transmission device, also have the mechanical type controlling device of the opening and closing CAP of can regulate valve (7,9).
6, according to the motor of claim 1, characteristics are that valve (7,9) control gear is electronic, hydraulic pressure or air-driven type, have the controlling device of reacting, with unlatching that changes valve (7,9) or the CAP of closing according to above-mentioned engine running parameter.
7, according to the motor of claim 1, characteristics are: above-mentioned control gear is adjusted into exhaust valve it is held open at least a portion stroke of swept volume increase stroke, is beneficial to suck air.
8, according to the motor of claim 7, characteristics are that compression ratio conforms to each Piston Compression stroke integral body when using above-mentioned control gear.
9, according to the motor of claim 7, characteristics are that the enable possition of intake valve is near the mid point of each descent of piston stroke.
10, according to the motor of claim 9, characteristics are that above-mentioned control gear makes inlet and outlet door (7,9) not be in opening state simultaneously.
11, according to the motor of claim 11, characteristics are to have single current to prevent that to device the waste gas of vent systems from flowing backwards in the vent systems, and above-mentioned control gear makes inlet and exhaust valve (7,9) be in the state of opening simultaneously in the engine section circulation.
12, according to the motor of claim 11, characteristics are that above-mentioned single current comprises that to device the fixedly outlet pipe of sufficient length is in order to the inertia effect that is used in motion waste gas post in the outlet pipe.
13, according to the motor of claim 11, to be above-mentioned single currents comprise the inertia effect of motion waste gas post in the fixedly outlet pipe of sufficient length to device to characteristics.
14, according to the motor of claim 11, characteristics are that motor comprises the unnecessary chamber more than three, and utilize the device that sprays effect, can utilize the exhaust pulses of coming out from a working room to get rid of the waste gas of another working room under the scavenging state.
15, according to the motor of claim 14, characteristics are working room's outlets with gas exhaust manifold between the pipeline that is communicated with to be shaped as convergent tubular or tubular for convergent-divergent, its outlet is consistent with the gas exhaust manifold air flow direction.
16, according to the motor of claim 12, characteristics are that the direction of air outlet flue outlet is consistent with airflow direction in the gas exhaust manifold, and are concentric with it.
17, according to the motor of claim 3, characteristics are that its vent systems directly is communicated with between the rotor of exhaust valve (9) and charging turbine (29), drive turbosupercharger to lean on exhaust to impact following of very lower powered operating mode.
18, according to the motor of claim 15, characteristics are that the gas exhaust manifold channel cross-section is constant and enough little, and the exhaust flow velocity of gas exhaust manifold downstream surpasses 0.4 Mach number at nominal situation.
19, according to the motor of claim 18, characteristics are: the lower exit of gas exhaust manifold communicates by a diffuser with the import of the turbine of turbosupercharger, and diffuser drops to flow velocity below 0.4 Mach number.
20, according to the motor of claim 17, characteristics are that the lower exit of gas exhaust manifold directly communicates with the import of turbosupercharger, and the latter's shunting collector ring is arranged to such an extent that the airspeed between gas exhaust manifold outlet and turbine rotor is not obviously reduced.
21, a kind of operating method of two-cycle engine, its characteristics are:
A) when parameter has the numerical value that conforms to the motor nominal situation, motor is just worked by the mode of stroke cycle.This circulation comprises:
-compression-burning-expansion stage when inlet and outlet door (7,9) is in the closed position.
The pulse exhaust cycle in-one expansion latter stage of having only that exhaust valve opens,-one scavenging period, intake valve (7) is opened simultaneously with exhaust valve (9) during this period, because the effect of both sides, working room positive pressure difference has at least a part of burnt gas to be replaced by fresh air
B) on the other hand, when operating parameters occurs that the expression motor can not rotate or during the value that is not suitable for moving, by control gear angular orientation that valve (7,9) opens shift to an earlier date with respect to the position of working room's maximum volume, so that the working room is connected in a part of process of swept volume of a single chamber increase at least with gas handling system.
22, according to the method for claim 21, characteristics are that unlatching with above-mentioned inlet and outlet door is constantly in advance in order to being used in a part of stroke that swept volume of a single chamber increases in the breathing process.
23, according to the method for claim 22, characteristics are single current to be set to device in vent systems, flow backwards to the working room with the waste gas that prevents vent systems.
24, according to the method for claim 22, characteristics are to stagger each other and avoid intake valve (7) and exhaust valve (9) that the state of opening is simultaneously arranged in angular orientation that closing of exhaust valve opened with air inlet.
25, method according to claim 21, characteristics are to be staggered by the conversion at the phase angle of camshaft in all positions of opening and closing of inlet and exhaust valve.
26, in accordance with the method for claim 21, its characteristics are: use asymmetric inlet and exhaust valve to open and close timing diagram, wherein IC Intake Valve Closes and the exhaust valve closing angular orientation that more above-mentioned inlet and outlet door is opened apart from the angular orientation of lower dead center (BDC) is farther.
27, according to the starting method of the described motor of claim 1, its characteristics are: to turbocharger supercharged motor, before engine start, exercise turbosupercharger earlier and quicken.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN87103277A CN1015019B (en) | 1987-05-03 | 1987-05-03 | Improvement of two-stroke internal combustion engine and operation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN87103277A CN1015019B (en) | 1987-05-03 | 1987-05-03 | Improvement of two-stroke internal combustion engine and operation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN87103277A CN87103277A (en) | 1988-11-23 |
| CN1015019B true CN1015019B (en) | 1991-12-04 |
Family
ID=4814368
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN87103277A Expired CN1015019B (en) | 1987-05-03 | 1987-05-03 | Improvement of two-stroke internal combustion engine and operation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1015019B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4281445B2 (en) * | 2003-07-08 | 2009-06-17 | トヨタ自動車株式会社 | Control device for internal combustion engine and control method for internal combustion engine |
| CN103016136A (en) * | 2012-12-14 | 2013-04-03 | 西华大学 | High-supercharged two-stroke direct injection engine and ventilation method thereof |
| CN104533564A (en) * | 2014-12-19 | 2015-04-22 | 朱譞晟 | Double-Atkinson-cycle internal combustion engine |
| CN106640338B (en) * | 2016-12-28 | 2019-03-08 | 天津大学 | A kind of overhead valve two-stroke directly spraying petrol engine combustion camber in cylinder |
| CN109931158A (en) * | 2017-12-19 | 2019-06-25 | 冯明勋 | Two stroke engine |
| CN108223121A (en) * | 2018-03-26 | 2018-06-29 | 郏政广 | Two stroke engine |
-
1987
- 1987-05-03 CN CN87103277A patent/CN1015019B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN87103277A (en) | 1988-11-23 |
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