CN100588833C - Ignition protection module, system and method of free-piston type internal-combustion engine - Google Patents
Ignition protection module, system and method of free-piston type internal-combustion engine Download PDFInfo
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- CN100588833C CN100588833C CN200810040915A CN200810040915A CN100588833C CN 100588833 C CN100588833 C CN 100588833C CN 200810040915 A CN200810040915 A CN 200810040915A CN 200810040915 A CN200810040915 A CN 200810040915A CN 100588833 C CN100588833 C CN 100588833C
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Abstract
A free piston type combustion engine ignition system, a method and a protective module belong to the combustion engine technical field. The system comprises an input signal sensor, an ignition actuator and an electronic control unit, wherein the input signal sensor comprises a Hall sensor and a linear displacement transducer; the linear displacement transducer is in electrical connection with theHall sensor and is triggered by the Hall sensor; the Hall sensor is arranged on the moving line of the connecting rod of a free piston type combustion engine. When the connecting rod passes, the Hallsensor triggers the linear displacement transducer to carry out induction of the displacement of the connecting rod; when the displacement reaches to a preset value, the electronic control unit controls the ignition actuator to carry out ignition; moreover, the connecting rod undergoes braking and backward movement by means of thermodynamics principle, and the process is repeated. The free pistontype combustion engine ignition system can realize realtime judgment of the position of the connecting rod so as to accurately control ignition time; meanwhile, ignition parameter can be flexibly adjusted according to operating condition so as to ensure that the free piston type combustion engine operates under an optimum condition.
Description
Technical field
What the present invention relates to is a kind of ignition protection module, system and method for technical field of internal combustion engines, specifically is a kind of free-piston type internal-combustion engine ignition protection module, system and method.
Background technique
Free-piston type internal-combustion engine is that mean engine has been cancelled common connecting rod, and piston motion is not subjected to a kind of extraordinary internal-combustion engine of physical constraint.Its structure generally comprises the cylinder of two coaxial openings in opposite directions, and reach a movable bar two and place this cylinder respectively, and back and forth movable vertically.Because be not subjected to the constraint of mechanical rod member, its power piston is freely, i.e. alterable compression ratio.Compare with traditional crank engine, the to-and-fro motion that it has saved in the curved shaft type internal-combustion engine piston is converted to the connecting rod that rotatablely moves, have simple in structure, number of parts is few, in light weight, cost is low, the efficient advantages of higher; And aspect stressed and motion, do not have lateral forces between piston and cylinder body, frictional force is little, thereby has prolonged the life-span of motor; Only do the piston assembly of linear reciprocating motion on the other hand, the start-stop of motor is relatively easy; Because alterable compression ratio is easy to use other substitute fuel, startability is good in addition.This shows that free-piston type internal-combustion engine has vast potential for future development.
In recent years, increasingly mature along with internal-combustion engine technology used extensively day by day, and people begin that traditional combustion engine is carried out exploration and improve research.Also begun basic exploratory development about free-piston type internal-combustion engine abroad, mainly launched around hydraulic free-piston formula internal-combustion engine and free-piston internal combustion generator.But now deep not enough to the research of free-piston type internal-combustion engine, also lack relevant report.
As everyone knows, in order to improve the performance of two stroke IC engine, adopting electronic control injection and ignition timing is the factor of most critical, if the control inaccuracy, then engine performance worsens, and Economy, power character are poor, even can not start.The subject matter that free-piston type internal-combustion engine faces appears in the control of top dead center.The control top dead center position can be realized variable compression ratio under different operating modes; Can the limited piston limit position, avoid being rebuffed and damage cylinder etc.And the control of top dead center is undertaken by the control ignition time usually.So top priority that to develop accurate, reliable, controllable electric fire control system device be free-piston type internal-combustion engine.
Through the literature search of prior art is found, the ignition system of the hydraulic free-piston formula internal-combustion engine of Zhejiang University's development has been introduced in " development of hydraulic free-piston engine ignition system " that people such as Zhejiang University's fluid transmission and control laboratory Zhang Yaqiang deliver on 2003 32 (1) at " compact internal combustion engine and motorcycle ".It utilizes the igniting of Hall switch fixed point pilot spark plug, belongs to hardware controls.But it can not adjust ignition location flexibly when variable working condition, and inappropriate time of ignition can make engine performance worsen under some operating mode, Economy, power character variation, the advantage of very difficult performance free-piston type internal-combustion engine alterable compression ratio.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, a kind of free-piston type internal-combustion engine ignition protection module, system and method are provided.Protection module of the present invention can be judged the relative movement situation of connecting rod and cylinder, and when this connecting rod was about to knock this cylinder head, positive ignition was to realize the protection to this free-piston type internal-combustion engine; System of the present invention can judge the position of connecting rod in real time, accurately to control firing time, can be according to operating mode free adjusting ignition parameter, to ensure that free-piston type internal-combustion engine operates in optimal conditions, wherein, this free-piston type internal-combustion engine ignition system is around declaring cylinder, ignition timing, the expansion of igniting least energy; Method of the present invention can be judged the position of connecting rod in real time, accurately to control firing time, can raise the efficiency according to operating mode free adjusting ignition parameter, operates in optimal conditions to ensure this free-piston type internal-combustion engine; Further, it can avoid connecting rod knock to damage this free-piston type internal-combustion engine to cylinder head.
The present invention is achieved by the following technical solutions:
Free-piston type internal-combustion engine ignition protection module involved in the present invention, comprise: velocity transducer, protection igniting final controlling element, Electronic Protection control unit, described Electronic Protection control unit is electrically connected on described velocity transducer and described protection igniting final controlling element, stores a critical velocity value;
Wherein, described velocity transducer is arranged in the cylinder of free-piston type internal-combustion engine; limit of sports record position predeterminable range from this free-piston type internal-combustion engine connecting rod; speed when responding to this connecting rod and arriving herein a flash; this critical velocity value can arrive the speed of this limit of sports record position just when freely compressing for this connecting rod; when this instantaneous velocity during greater than this critical velocity value, described electronic control protected location is controlled the igniting of described protection igniting final controlling element.
Free-piston type internal-combustion engine ignition system involved in the present invention, comprise: input pickup, igniting final controlling element, electronic control unit, described electronic control unit is electrically connected on described input pickup and described igniting final controlling element, be used for from described input pickup acknowledge(ment) signal, and control described igniting final controlling element igniting;
Described input pickup comprises Hall transducer and linear displacement transducer, and described linear displacement transducer is electrically connected on described Hall transducer, and is triggered by this Hall transducer;
Wherein, described Hall transducer is arranged on the moving line of connecting rod of free-piston type internal-combustion engine, when this connecting rod passes through, described Hall transducer triggers the displacement amount that described linear displacement transducer begins accurately to respond to this connecting rod, when this displacement amount arrives a predefined value, the described igniting final controlling element igniting of described electronic control unit controls utilizes thermodynamic principle to make this connecting rod braking and reversing motion, in this way repeatedly.
Free-piston type internal-combustion engine ignition method involved in the present invention comprises the steps:
The first step produces an igniting reference signal when the connecting rod of free-piston type internal-combustion engine passes through a predeterminated position;
Second step, receive this reference ignition signal after, this connecting rod of accurate Calculation surpasses the side-play amount of this predeterminated position;
In the 3rd step, the predefined value in this side-play amount and the internal memory is compared;
The 4th step, when this side-play amount equates with this predefined value, in the firing chamber in this link motion direction the place ahead, light a fire, wherein, described predefined value can regulate.
Because ignition internal combustion engine firing chamber clearance volume is bigger, free-piston does not have physical constraint, if move the improper cylinder cap that is easy to run into, causes danger.Under this abnormal conditions, need the improvement that the associated safety measure cooperates the firing chamber physical form, particularly, adopt the method for positive ignition to avoid free-piston to run into cylinder cap, step is:
The first step is provided with a velocity transducer apart from a certain distance in limit of sports record position in the opposed cylinder of free-piston type internal-combustion engine, the instantaneous velocity when the detection free-piston reaches this;
In second step, when critical velocity value that this instantaneous velocity is stored in greater than internal memory, the positive ignition firing chamber in link motion the place ahead in is done work to piston, avoids it to run into cylinder cap.Wherein, this critical velocity value is the speed that connecting rod can arrive this limit of sports record position when freely compressing just.
Under the normal condition, this positive ignition is not had an effect.
Compared with prior art, the present invention mainly has following advantage: the cylinder of declaring that carries out the free-piston motion more accurately, mode by software realizes variable time of ignition and ignition energy, wherein, ignition timing can be as accurate as 0.1mm at least, if signal is carried out process of frequency multiplication, precision can be brought up to 0.025mm; Utilize security protection module to remedy the intrinsic defect of the combustion-chamber shape of ignition internal combustion engine, further guarantee the safe operation of free piston internal combustion engine system.
Description of drawings
Fig. 1 is the structural representation of embodiment of the invention free-piston type internal-combustion engine ignition system;
Among the figure: 1 is first firing chamber; 2 are the igniting final controlling element; 3 is first relief opening; 4 is electronic control unit; 5 is linear displacement transducer, comprises magnetic grid tooth bar 501 and magnetic grid read head 502; 6 is second relief opening; 7 is cylinder; 8 is second firing chamber; 9 is second piston; 10 is second suction port; 11 is connecting rod; 12 is Hall transducer, comprises tooth 1201 and hall signal generator 1202; 13 is first suction port; 14 is first piston; 15 is velocity transducer.
Fig. 2 is the igniting actuator structure schematic representation in the preferred embodiment;
Among the figure, 201 is sampling resistor; 202 is voltage comparator; 203 is logic controller; 204 are the mos pipe; 205 are protection electric capacity; 206 is that spark coil is elementary; 207 is that spark coil is secondary; 208 is spark plug; 209 is diode; 210 is switch; 211 is the 12V DC electrical source; 212 is protective resistance.
Spark coil primary current and time relationship schematic representation when Fig. 3 is charging pulsewidth 3ms.
Fig. 4 is spark coil secondary high pressure and time relationship schematic representation.
Spark coil Current limited Control figure when Fig. 5 is charging pulsewidth 6ms;
Wherein: (a) being spark coil primary current and time relationship, (b) is spark coil secondary voltage and time relationship.
Fig. 6 is the general figure of the needed critical velocity arteries and veins of ignition protection module.
Fig. 7 is the fast simulation curve schematic representation of ignition protection film;
Wherein: displacement and time when a is the unprotect module, b be protection module when working displacement and time change.
Embodiment
Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention, provided detailed mode of execution and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
As shown in Figure 1, a free-piston type internal-combustion engine ignition system, it comprises:
One input pickup comprises a Hall transducer 12, reaches a linear displacement transducer 5 and is electrically connected on this Hall transducer, and triggered by this Hall transducer;
One igniting final controlling element 2; And
One electronic control unit 4 is electrically connected on input pickup and igniting final controlling element 2, is used for accepting a signal from input pickup, and 2 igniting of control ignition final controlling element;
Wherein, this Hall transducer 12 is arranged on the moving line of connecting rod 11 of free-piston type internal-combustion engine, when connecting rod 11 passes through, Hall transducer 12 triggers the accurately displacement amount of induction connecting rod 11 of linear displacement transducer 5 beginnings, when displacement amount arrives a predefined value, the igniting of the corresponding igniting of electronic control unit 4 controls final controlling element utilizes thermodynamic principle to make connecting rod 11 braking and reversing motions, in this way repeatedly.
Particularly, Hall transducer 12 connecting rod 11 by the time produce this signal, linear displacement transducer 5 is received the displacement amount of opening entry connecting rod 11 behind this signal.This predefined value is stored in this electronic control unit 4, compares with this displacement amount.
Particularly, electronic control unit 4 can be used to handle the input pickup signal for one 16 microprocessor (MCU), further triggers the work of corresponding igniting final controlling element.
As shown in Figure 2; according to a preferred embodiment, this igniting final controlling element 2 comprises that spark coil is elementary 206, secondary 207, one spark plug 208, a voltage comparator 202, a MOS transistor (mos pipe) 204, one 12V DC electrical source 211, a sampling resistor 201, a logic controller 203, a diode 209, protection electric capacity 205, a protective resistance 212 and a switch 210.
Further, spark plug 208 links to each other with this spark coil secondary 207 and ground connection; 12V DC electrical source 211 links to each other with the drain electrode of mos pipe 204 by switch 210, diode 209, spark coil elementary 206, adds protection electric capacity 205 and protective resistance 212 and ground connection in 204 drain electrodes of mos pipe, to avoid the excessive mos of the burning pipe of transient current.Mos manages 204 source electrodes by sampling resistor 201 ground connection; Elementary 206 charging currents of spark coil are introduced mos with an ignition control signal by logic controller 203 with charging restriction electric current and are managed 204 grids after over-voltage comparator 202, control mos pipe is operated under the different conditions.
The concrete working procedure of igniting final controlling element 2 is as follows, and in default reference ignition position, electronic control unit 4 control mos manage 204 conductings, to elementary 206 chargings of spark coil.In ignition timing, control mos pipe 204 ends, thereby in spark coil secondary 207, produce high pressure (＞10kV), make spark plug 208 igniting.When free-piston type internal-combustion engine breaks down; it is unusual that charging might take place; primary air 206 chargings can make this spark coil or mos pipe 204 cross cause thermal damage unusually; the real charging current size that detects when utilizing voltage comparator 202; after surpassing charging restriction electric current; voltage comparator 202 output switching activities make mos pipe 204 be offset to the constant current district by the variable resistor district by logic controller 203, to reduce charging current.
The present invention also provides a kind of ignition method that is used for free-piston type internal-combustion engine, and it comprises:
When passing through a predeterminated position, connecting rod 11 produces an igniting reference signal;
After receiving this reference ignition signal, accurate Calculation connecting rod 11 surpasses a side-play amount of this predeterminated position;
Predefined value in this side-play amount and the internal memory is compared;
When this side-play amount equates with this predefined value, in the firing chamber in link motion direction the place ahead, light a fire, wherein, this predefined value can regulate.
Further; this ignition method also comprises: speed when induction connecting rod 11 arrives a flash of a predetermined position; when this instantaneous velocity during greater than this critical velocity value; the igniting of the corresponding protection igniting of this electronic control protected location control final controlling element; wherein, this critical velocity value is the speed that connecting rod 11 can arrive limit of sports record position (piston is run into cylinder cap) when freely compressing just.
The present invention also provides a kind of ignition protection module that is used for free-piston type internal-combustion engine, and it comprises:
One velocity transducer 15;
One protection igniting final controlling element can be igniting final controlling element 2 particularly; And
One Electronic Protection control unit can be electronic control unit 4 particularly, is electrically connected on this velocity transducer 15 and this protection igniting final controlling element 2, stores a critical velocity value;
Wherein, velocity transducer 15 is arranged in the opposed cylinder of a free-piston type internal-combustion engine; limit of sports record position one predeterminable range from the connecting rod 11 of this free-piston type internal-combustion engine; speed when induction connecting rod 11 arrives herein a flash; this critical velocity value is the speed that connecting rod 11 can arrive this limit of sports record position when freely compressing just; when this instantaneous velocity during greater than this critical velocity value, this protection igniting final controlling element 2 igniting of these electronic control protected location 4 controls.
Preferred embodiment
As shown in Figure 1, the free piston internal combustion engine of present embodiment employing comprises: first firing chamber 1, igniting final controlling element 2 (comprises sampling resistor 201, voltage comparator 202, logic controller 203, mos pipe 204, protection electric capacity 205, spark coil elementary 206, spark coil secondary 207, spark plug 208, diode 209, switch 210,12V DC electrical source 211, protective resistance 212), first relief opening 3, electronic control unit 4, linear displacement transducer 5 (comprising magnetic grid tooth bar 501 and magnetic grid read head 502), second relief opening 6, cylinder 7, second firing chamber 8, second piston 9, second suction port 10, connecting rod 11; Hall transducer 12 (comprising tooth 1201 and hall signal generator 1202), first suction port 13; First piston 14; Velocity transducer 15.
The first piston 14 and second piston 9 are formed one to interposed structure by middle connecting rod 11, constitute unique moving element of free-piston type internal-combustion engine, and first firing chamber 1, second firing chamber 8 are opposite to the system both sides, wherein arrange igniting final controlling element 2 respectively.6 mouthfuls of first suction port 13, first relief opening 3 and second suction port 10, second exhausts also are set respectively in two firing chambers.Spark plug 208 links to each other with spark coil secondary 207 and ground connection; 12V DC electrical source 211 links to each other with 204 drain electrodes of mos pipe by switch 210, diode 209, spark coil elementary 206, adds protection electric capacity 205 and protective resistance 212 and ground connection in 204 drain electrodes of mos pipe, to avoid the excessive mos of the burning pipe of transient current; Mos manages 204 source electrodes by sampling resistor 201 ground connection; Elementary 206 electric currents of spark coil are introduced voltage comparator 202 and are produced the overcurrent protection signal, send into logic controller 203 processing with the ignition control signal that electronic control unit 4 sends, and the signal after the processing is directly introduced mos and managed 204 grids.Tooth 1201 is arranged in the central authorities of connecting rod 11, to-and-fro motion thereupon, and it is motionless that hall signal generator 1202 is fixed in two firing chamber central authorities, is electrically connected with electronic control unit 4.Magnetic grid tooth bar 501 is arranged on the free piston internal combustion engine connecting rod 11, movement therewith, and it is middle motionless that magnetic grid read head 502 is fixed in two firing chambers, is electrically connected with electronic control unit 4.
Below in conjunction with accompanying drawing concrete enforcement of the present invention is further described.In position shown in Figure 1, connecting rod 11 is with the top dead center motion to the left of first piston 14, second piston 9.At this moment, hall signal generator 1202 is judged tooth 1201 already and is passed through, and produces signal and gives electronic control unit 4, and the default reference ignition signal of prompting arrives.Electronic control unit 4 gives the igniting final controlling element 2 signals at once, further makes linear displacement transducer 5 enter working state, and beginning accurate Calculation connecting rod 11 surpasses the side-play amount of predeterminated position, compares with predefined value in the internal memory.At the opposite side of free-piston type internal-combustion engine, inflammable mixture enters cylinder by second intake valve 10 simultaneously, impels the residual exhaust gases in second firing chamber 8 to discharge through second relief opening 6, finishes the scavenging process of second firing chamber 8.Along with connecting rod 11 further to left movement, the default time of ignition of first firing chamber 1 arrives, ignition function is finished in 2 work of electronic control unit 4 control ignition final controlling element.The pressurized gas that 1 burning of first firing chamber produces promote connecting rod 11 and move to the right with first piston 14, second piston 9, finish above-mentioned identical action.Free-piston type internal-combustion engine produces straight line motion in this manner, externally directly acting, output energy.
The specific implementation process of igniting final controlling element 2 is as follows:
Free-piston type internal-combustion engine starts, switch 210 closures, reference ignition signal comes interim, electronic control unit 4 sends signal, mos manages 204 conductings, 12V DC electrical source 211 produces that electric currents are elementary 206 by switch 210, diode 209, spark coil, mos pipe, sampling resistor 201 form closed-loop paths, the increase of starting from scratch of elementary 206 electric currents of spark coil.Ignition timing comes interim, and electronic control unit 4 sends signal, and mos pipe 204 ends, and spark coil secondary 207 induces high pressure, punctures mixed gas, spark plug 208 igniting.Ignition timing if charging current surpasses maximum allowed current (7.56A), voltage comparator 202 overturns, output low level, through behind the logic controller 203, control mos pipe 204 is offset to the constant current district by the variable resistor district, elementary 206 charging currents of spark coil reduce, and ensure that mos manages 204 proper functioning.
Present embodiment is achieved through the following technical solutions declares cylinder and ignition timing:
The maximum characteristics of free-piston type internal-combustion engine are exactly that the motion of connecting rod 11 is by the decision of first firing chamber 1, second firing chamber, 8 combustion positions, a preceding combustion process directly influences motion next time, therefore, the top dead center position of first piston 14, second piston 9 is unfixing, along with load, ignition location etc. change.Different time of ignition has decisive role to the characteristics of motion, the efficient of internal-combustion engine, adjusts time of ignition according to load and can ensure that internal combustion engine operation is in optimum condition.
Budc igniting: realize reference ignition and ignition timing function respectively through the Hall transducer 12 of Shelving and the signal of linear displacement transducer 5.Processing can be by the tooth 1201 of hall signal generator 1202 resolutions, along with connecting rod 11 moves together on connecting rod 11.Hall signal generator 1202 detects tooth 1201 processes, and to square wave of electronic control unit 4 outputs, the prompting predeterminated position arrives.This square wave is used as reference ignition signal, control ignition coil elementary 206 begins charging, trigger linear displacement transducer 5 simultaneously and begin counting, (counter overflows) enters interrupt routine in ignition timing, electronic control unit 4 control ignition signals drag down, mos pipe 204 ends, and spark coil secondary 207 induces high pressure, spark plug 208 igniting.When needing to adjust ignition location, only need to revise the counter initial value of linear displacement transducer 5, guarantee that the precision of igniting is 0.01～0.1mm.
The atdc igniting: because the top dead center position of first piston 14, second piston 9 is variable, preceding method obviously can not accurately be judged the ignition location of atdc.Corresponding this kind situation should utilize the piston top dead center signal as declaring cylinder signal.The real seizure A of linear displacement transducer 5, the moment of B signal rising edge made the judgement of connecting rod 11 moving direction during electronic control unit 4; Changing at A, B signal phase difference, this moment of mark is the circulation top dead center position in (moving direction change), cylinder signal is declared in generation, triggers linear displacement transducer 5 countings, and is same according to different initial values, finish the igniting of atdc particular location, precision is 0.010～0.1mm.
Situation for the budc igniting, tooth 1201 is being understood triggering hall signal generator 1,202 twice near top dead center with away from the movement process of top dead center, make Hall transducer 12 export two square waves, if the pulse signal of Hall transducer 12 does not add filtration treatment directly as reference ignition signal, each circulation will produce the fire signal of a mistake, and the pulse that therefore must be with tooth 1201 triggers during away from top dead center is shielded.
Present embodiment is achieved through the following technical solutions the control of ignition energy:
According to the spark coil technical parameter, elementary 206 charging currents of spark coil change with being index law current"on"time, primary current decision ignition energy.Spark coil elementary 206 adopts 211 power supplies of 12V DC electrical source, keeping the 3ms duration of charge just can produce ignition voltage more than the 10kV in secondary 207, ignition energy reaches more than the 50mJ, the igniting needs when satisfying normal working of engine, and therefore being set this duration of charge is basic pulsewidth.Be not subjected to the influence of 12V DC electrical source 211 voltage change in order to ensure ignition energy and secondary 207 voltages, when DC electrical source 211 voltage step-downs, should suitably increase the duration of charge.
Present embodiment is achieved through the following technical solutions the safety protection effect:
Because the firing chamber of plug ignition formula internal-combustion engine mostly is the hemispherical combustion chamber, clearance volume is big, and maximum compression ratio is limited.First piston 14 does not have fixing top dead center, incorrect and piston inertia was crossed and may well be run into first firing chamber, 1 limit position (cylinder cap) and cause danger default firing time, same, second piston 9 might be run into second firing chamber, 8 limit positions (cylinder cap) and cause danger.To this abnormal conditions, except improving the internal combustion (IC) Engine Design parameter, also need to add the auxiliary protection measure.The positive ignition module is set in ignition system, and the introducing critical velocity also is stored in electronic control unit 4 internal memories.Here, the size of critical velocity is relevant with the load of internal-combustion engine, supposes under this speed, and first piston 14, second piston 9 can freely be compressed to the limit position of first firing chamber 1 or second firing chamber 8 just.With 3mm part before the limit position as sampled point, sampling first piston 14, second piston, 9 speed, compare with the critical velocity of storage, if sample rate surpasses critical velocity, the corresponding mos pipe 204 of electronic control unit semi-finals system ends immediately, corresponding spark plug 208 igniting are done negative work to piston, offset unnecessary kinetic energy.
Embodiment's emulation
The computer simulation cost is low, can react the object of being studied comparatively accurately.Concerning ignition system proposed by the invention, by simulation modeling, can investigate the different operating process of this ignition system under normal and unusual condition, help further understanding in depth the characteristic of this ignition system.
(1). the emulation of normal ignition situation
High-energy ignition coil parameter: elementary winding 0.55 Ω, inductance 5.8mH; Secondary windings 6.2k Ω, inductance 14H; Energy conversion efficiency 75%, sampling resistor 0.1 Ω.According to calculating, the time constant of present design primary circuit is about 8.9ms, and under the time that recharges here, elementary cut-out electric current does not add restriction and can reach more than the 10A, does not adopt Current limited Control not only to waste electric energy, and circuit is damaged.Utilize Matlab/Simulink to program, primary current and secondary voltage change shown in Fig. 3,4,5 under the different duration of charge of test.Wherein Fig. 3,4 couples of inductive charging pulsewidth 3ms, Fig. 5 is to inductive charging pulsewidth 6ms.
By simulation result as seen, the control pulsewidth continues 3ms just can make primary air energy storage 50mJ, identical with the technical parameter of spark coil.When engine start, idling and acceleration or lean combustion, mixed gas is difficult to light, and needs higher ignition energy, in the case, also should adjust the charging pulsewidth to more than the 5ms, makes ignition energy reach 100mJ.And pulsewidth is when reaching 6ms, and electric current has reached the safe current upper limit of setting, and the current-limiting protection module has played the effect of expection, and the restriction charging current is stabilized in 7.56A.
Table 1 has been summed up the elementary cut-out electric current of difference charging pulsewidth down-firing coil, secondary voltage and the ignition energy Changing Pattern of this design proposal.As can be seen, the pulsewidth that surpasses 6ms has not had practical significance, to ignition system without any influence.
Table 1 spark coil electrical characteristic table
Duration of charge/ms 123456
Cut off electric current/A 1.81 3.4 4.82 6.06 7.15 7.56
Secondary voltage/kV 6.165 11.58 16.4 20.61 24.35 25.75
Ignition energy/mJ 7.1 25.2 50.6 79.9 111.3 124.3
(2) ignition protection module emulation
A. critical velocity is found the solution
This free-piston type internal-combustion engine system comprises the thermodynamic process of firing chamber and the dynamics part of piston motion, and modeling is as follows respectively:
Thermodynamic model
For certain load, suppose that critical velocity is v
0, gas pressure, volume satisfy in the compression stroke firing chamber
In the formula, C
v, R
gBe respectively specific heat at constant volume and gas case constant, P, V are respectively gas instantaneous pressure and volume,
Be gas and heat exchange with outside, comprise the energy of fuel combustion and externally heat radiation.
The energy that fuel combustion produces satisfies
H in the formula
uBe the lower calorific value of fuel, G
bFor each circulation sprays into fuel mass in the cylinder,
Be rate of burning,, have according to the Wiebe formula
N is the fuel quality number in the formula, and gasoline is generally got constant between 1～3.Tz is that firing duration is ignored the variation of heat-transfer coefficient with the space, and in the internal-combustion engine movement process, radiation loss is satisfied
In the formula, T, T
wBe respectively working medium transient temperature and wall surface temperature in the cylinder; H is a convective heat transfer coefficient, and A is effective heat transfer area, comprises the heat transfer area that piston head surface area, cylinder cap inner surface area and combustion gas contact with cylinder wall.According to the Eichelberg empirical correlation that research draws to natural aspiration low speed two-stroke
V in the formula
mBe mean piston speed
Bring (2)～(5) into (1), can obtain the dynamic rule of combustion chamber heat mechanical process and in-cylinder pressure.
Dynamic model
Piston is carried out force analysis, according to Newton's second law
P in the formula
1, P
2Be respectively left and right sides gas pressure, S is that piston cross-section is long-pending, F
MagBe respectively load force (electromagnetic force) and frictional force with f, all be directly proportional with movement velocity, scaling factor is with load variations.
The set of equation that thermodynamic model and dynamic model combine and can obtain sealing, the practical work process of description free-piston type internal-combustion engine.
Critical velocity is found the solution
According to the model of actual free piston internal combustion engine, fuel H is set
u=43500kJ/kg, n=3 supplies with gas adiabatic exponent 1.37, specific heat at constant pressure 788J/ (kgK), wall mean temperature 400K according to equivalent proportion.Utilize matlab to program, find the solution the critical velocity under the different loads in conjunction with above-mentioned initial conditions solution formula (1)-(6), the result as shown in Figure 6.
Make the arteries and veins spectrogram according to this critical velocity, make electronic control unit detect the movement velocity of this position piston,, control the mos pipe at once and end, make plug ignition, ensure the free-piston type internal-combustion engine safe operation in case surpass this numerical value.
B. ignition protection module emulation
Abnormal state artificially is set, makes MCU detect velocity of piston and surpass critical velocity, the igniting of positive ignition system, the change of system motion rule before and after the contrast positive ignition.Burn cycle gas heat release 50J in cylinder is set, is equivalent to fuel oil and supplies with according to stoichiometric, capacity usage ratio is about 26%.Fig. 7 has described piston head to the distance of limit position change curve in time, and the sample rate of setting is 2.1m/s.Curve 1 the two spacing when not having protective action changes, and curve b has described protection module the latter two spacings that work and changed, and this moment, MCU detected unusually, made the spark plug positive ignition.Clearly, because movement velocity surpasses critical velocity, the part of curve a has been positioned under the horizontal line, and this shows that piston position surpasses cylinder cap, will cause danger; And take after the positive ignition measure, velocity of piston had been reduced to zero before limit position, guarantee the free-piston type internal-combustion engine safe operation.As can be seen, can effectively remedy the negative effect that bring the traditional combustion chamber, cooperate other corrective measure to ensure the safe operation of free piston internal combustion engine jointly based on the security protection module of positive ignition.
Claims (5)
1. free-piston type internal-combustion engine ignition protection module, it is characterized in that, comprise: velocity transducer, protection igniting final controlling element, Electronic Protection control unit, described Electronic Protection control unit is electrically connected on described velocity transducer and described protection igniting final controlling element, stores a critical velocity value;
Wherein, described velocity transducer is arranged in the cylinder of free-piston type internal-combustion engine; limit of sports record position predeterminable range from this free-piston type internal-combustion engine connecting rod; speed when responding to this connecting rod and arriving herein a flash; this critical velocity value can arrive the speed of this limit of sports record position just when freely compressing for this connecting rod; when this instantaneous velocity during greater than this critical velocity value, described electronic control protected location is controlled the igniting of described protection igniting final controlling element.
2. free-piston type internal-combustion engine ignition system, it is characterized in that, comprise: input pickup, igniting final controlling element, electronic control unit, described electronic control unit is electrically connected on described input pickup and described igniting final controlling element, be used for from described input pickup acknowledge(ment) signal, and control described igniting final controlling element igniting;
Described input pickup comprises Hall transducer and linear displacement transducer, and described linear displacement transducer is electrically connected on described Hall transducer, and is triggered by this Hall transducer;
Described igniting final controlling element comprises: a spark coil, a spark plug, a voltage comparator, mos pipe, a 12V DC electrical source, a sampling resistor, a logic controller, a diode, are protected electric capacity, a protective resistance, are reached a switch; Wherein, described spark plug links to each other and ground connection with described spark coil is secondary, described 12V DC electrical source is passed through described switch, diode, spark coil is elementary links to each other with the drain electrode of described mos pipe, add described protection electric capacity and protective resistance and ground connection in this mos pipe drain electrode, to avoid the excessive mos of the burning pipe of transient current, this mos pipe source electrode is by described sampling resistor ground connection; The elementary charging current of described spark coil is introduced described mos tube grid with an ignition control signal by described logic controller through behind the described voltage comparator with charging restriction electric current, controls described mos pipe and is operated under the different conditions;
Wherein, described Hall transducer is arranged on the moving line of connecting rod of free-piston type internal-combustion engine, when this connecting rod passes through, described Hall transducer triggers the displacement amount that described linear displacement transducer begins to respond to this connecting rod, when this displacement amount arrives a predefined value, the described igniting final controlling element igniting of described electronic control unit controls utilizes thermodynamic principle to make this connecting rod braking and reversing motion, in this way repeatedly.
3. free-piston type internal-combustion engine ignition system as claimed in claim 2, it is characterized in that, described Hall transducer this connecting rod by the time produce this signal, described linear displacement transducer is received this displacement amount of this connecting rod of opening entry behind this signal, this predefined value is stored in the described electronic control unit, compares with this displacement amount.
4. a free-piston type internal-combustion engine ignition method is characterized in that, comprises the steps:
The first step produces an igniting reference signal when the connecting rod of free-piston type internal-combustion engine passes through a predeterminated position;
Second step, receive this reference ignition signal after, calculate the side-play amount that this connecting rod surpasses this predeterminated position;
In the 3rd step, the predefined value in this side-play amount and the internal memory is compared;
The 4th step, when this side-play amount equates with this predefined value, in the firing chamber in this link motion direction the place ahead, light a fire, wherein, described predefined value can regulate.
5. free-piston type internal-combustion engine ignition method as claimed in claim 4 is characterized in that, adopts the method for positive ignition to avoid the free-piston motion to run into cylinder cap, and described positive ignition step is:
The first step is provided with a velocity transducer apart from a certain distance in limit of sports record position in the opposed cylinder of free-piston type internal-combustion engine, the instantaneous velocity when the detection free-piston reaches this;
Second step, when critical velocity value that this instantaneous velocity is stored in greater than internal memory, positive ignition in the firing chamber in link motion the place ahead, piston is done work, avoid it to run into cylinder cap, wherein, this critical velocity value is the speed that connecting rod can arrive this limit of sports record position when freely compressing just.
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| KR101171905B1 (en) * | 2009-06-09 | 2012-08-07 | 기아자동차주식회사 | Ignition system of engine and control method thereof |
| CN101915194A (en) * | 2010-07-09 | 2010-12-15 | 天津理工大学 | Rotation speed synchronizing signal-based spark plug sparking control device |
| CN104595027A (en) * | 2013-11-01 | 2015-05-06 | 中国船舶重工集团公司第七一〇研究所 | Piston type internal combustion engine |
| US11346219B2 (en) | 2014-04-24 | 2022-05-31 | Aquarius Engines (A.M.) Ltd. | Engine with work stroke and gas exchange through piston rod |
| CN106050517A (en) * | 2016-07-26 | 2016-10-26 | 北京理工大学 | Ignition control method for spark ignition type free piston linear generators |
| US10641166B1 (en) | 2018-12-03 | 2020-05-05 | Aquarius Engines (A.M.) Ltd. | Piston rod and free piston engine |
| US11008959B2 (en) * | 2019-06-28 | 2021-05-18 | Aquarius Engines Central Europe Sp. z o.o. | System and method for controlling engine using reference point |
| CN110608094B (en) * | 2019-09-20 | 2022-12-16 | 山东休普动力科技股份有限公司 | Back-mounted double-winding double-piston type free piston linear generator with motor |
| CN112302790A (en) * | 2020-09-04 | 2021-02-02 | 山东休普动力科技股份有限公司 | Device and method for identifying position and speed of free piston engine |
| CN112324563B (en) * | 2020-09-27 | 2022-01-07 | 山东休普动力科技股份有限公司 | Double-winding free piston linear generator and control method |
| CN113702051B (en) * | 2021-08-31 | 2022-05-17 | 北京交通大学 | Constant volume device and method for simulating turbulent direct injection combustion |
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