CN102072818A - Method for obtaining fire detection signal of cylinder of engine with speed sensor arranged in front - Google Patents

Abstract

The present invention discloses a method for obtaining a fire detection signal of each cylinder of an engine with a speed sensor arranged in the front, which comprises the following steps: calculating the difference of segment time of adjacent cylinders caused by a torsion torque according to the segment time of each cylinder of the engine detected by the speed sensor and the pre-calibrated torsion characteristic value of the adjacent cylinders of the engine, deducting the segment time of the adjacent cylinders caused by the torsion torque from the total difference of the segment time of the adjacent cylinders, and respectively calculating and outputting the fire detection signal of each cylinder of the engine. By adopting the method, the accurate fire detection signal can still be provided when the signal wheel of the speed sensor is arranged at the end of a belt pulley, the quality of the fire detection signal is improved in a project with the speed sensor arranged in the front of the engine, and the operating reliability of the fire detection function is improved.

Description

Obtain the catch fire method of detection signal of each cylinder of engine when speed probe is preposition

Technical field

The present invention relates to automobile electronic fuel oil jet onboard diagnostic system (OBD), particularly a kind of speed probe obtains the catch fire method of detection signal of each cylinder of engine when preposition.

Background technology

Definition according to relevant onboard diagnostic system (OBD) in existing light-duty vehicle pollutant emission limit of China and the measuring method (GB18352.3-2005), the detection of catching fire is an important component part in the OBD system, automobile factory declares that the type of vehicle authentication time must be stated the fire loss ratio determining to cause discharging when exceeding standard and causes the overheated fire loss ratio that causes irreversible damage of exhaust catalyst converter because of catching fire, the fire loss ratio of setting when determining type approval, to guarantee to detect quality when requiring vehicle to catch fire on the one hand, be to guarantee that vehicle operating just often can not judge by accident to catching fire on the other hand, and there is contradiction in this two aspect, so just automobile electronic fuel oil jet system (EMS) quality of match that detects of catching fire is had higher requirement.Each EMS coupling company fire detecting method all is based on can cause crankshaft rotating this principle that fluctuates when speed probe can perception catches fire, difference is to be the processing and the computing method of signals of rotational speed sensor are existed than big-difference, therefore correctly whether catch fire speed probe to detect original signal (crankshaft rotating fluctuation) be to be related to the condition precedent of detection signal accuracy of catching fire by perception, thereby be directly connected to the quality of match of the detection of catching fire.

Installation site about speed probe, normally be installed in engine flywheel end (clutch end), reason is that signals of rotational speed sensor wheel is contained in the flywheel side and near flywheel, because of flywheel has the energy storage effect, can increase the stationarity of signals of rotational speed sensor wheel running, and if to be contained in motor head be pulley end, because of the torsional oscillation of engine and kinematic train exists, can descend than being contained in its stationarity of flywheel end, thereby can influence the quality of match of catching fire and detecting.

But, along with becoming, engine and kinematic train become increasingly complex, be subjected to space constraint, the signals of rotational speed sensor wheel of more and more vehicles is had to preposition, be installed in the engine belt pulley end, the torsional oscillation of engine and kinematic train can be unfavorable greatly to the quality generation of the detection signal that catches fire like this, the detection signal quality of catching fire can descend, particularly under the inadequate situation of high rotating speed, relevant self study (self study of signal gear teeth deviation, fuel feeding self study promptly each cylinder is burnt inhomogeneity self study), can not guarantee the good detection signal quality of catching fire.

Present many signals of rotational speed sensor wheels are installed in the vehicle of engine belt pulley end, its generally be by control machining precision reduce engine and kinematic train torsional oscillation to the detection signal quality influence of catching fire, thereby the detection quality of catching fire increases, but still can not fundamentally get rid of because of the interference of shafting torsional oscillation to the running of signals of rotational speed sensor wheel.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of speed probe and obtains the catch fire method of detection signal of each cylinder of engine when preposition, when the signals of rotational speed sensor wheel is installed in pulley end, still can provide the detection signal that catches fire accurately.

For solving the problems of the technologies described above, speed probe of the present invention obtains the catch fire method of detection signal of each cylinder of engine when preposition, and engine comprises the 0th to N-1 N adjacent in regular turn cylinder, and N is a positive integer, may further comprise the steps:

One. demarcate the torsional vibration characteristic value between adjacent each cylinder of engine;

Two. split time tsk (the 0)～tsk (N-1) of each cylinder of speed probe detection of engine by being installed in the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that causes by the torsional oscillation moment of torsion,

${\mathrm{dtsk}}^{\′}\left(i\right)=K\left(i\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}},$

I is positive integer and 1≤i≤N-1, and dtsk ' is the difference of the split time between same i-1 the cylinder of i cylinder (i), and K (i) is the torsional vibration characteristic value between same i-1 the cylinder of i cylinder, and midmd is an engine load, and nmot is an engine speed;

Four. calculate the detection signal that catches fire of each cylinder of output engine respectively,

The detection signal that catches fire of the 0th cylinder: $\mathrm{luts}\left(0\right)=\frac{\mathrm{tsk}\left(0\right)-\mathrm{tsk}(N-1)}{{\mathrm{tsk}}^3\left(0\right)},$

The detection signal that catches fire of i cylinder: $\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{[\mathrm{tsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right)]}^3}$

Tsk (i) is the split time of i cylinder.

Torsional vibration characteristic value between adjacent each cylinder is definite by the following method,

One. measure repeatedly the split time of each cylinder under each operating mode;

Two. calculate under each operating mode each cylinder of engine with the mean difference of the split time between its last cylinder, computing method are that the split time to two adjacent cylinder under the same operating mode subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under this operating mode, again to this repeatedly under this operating mode the difference of the split time of this two adjacent cylinder ask average and obtain the mean difference of the split time between this two adjacent cylinder under this operating mode;

Three. calculate the torsional vibration characteristic value between each cylinder under the various operating modes,

$\mathrm{Ke}\left(i\right)=\frac{\mathrm{dtske}\left(i\right)*\mathrm{nmote}}{\mathrm{midmde}}$

Ke (i) be under the e kind operating mode i cylinder with the torsional vibration characteristic value between its last cylinder, dtske (i) be under the e kind operating mode i cylinder with the mean difference of the split time between its previous cylinder, midmde is the engine load under the e kind operating mode, and nmote is the engine speed under the e kind operating mode;

Four. the torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged, obtain the torsional vibration characteristic value between adjacent each cylinder.

Torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged, obtain the torsional vibration characteristic value between adjacent each cylinder, then can according to the torsional vibration characteristic value between adjacent each cylinder and should be 0 characteristic, the 0th cylinder revised the torsional vibration characteristic value that obtains between other final adjacent each cylinder with the torsional vibration characteristic value between other adjacent each cylinder outside the torsional vibration characteristic value between its previous cylinder.

For the automatic gear-box automobile, can be at the lockup state of automatic gear-box, do not measure repeatedly the split time of each cylinder under each operating mode under the lockup state two states respectively, obtain the torsional vibration characteristic value between each cylinder under the automatic gear-box two states respectively.

Speed probe of the present invention obtains the catch fire method of detection signal of each cylinder of engine when preposition, the catch fire size of detection signal luts (i) of i cylinder is directly proportional with the difference of last cylinder split time with this cylinder split time, pay the utmost attention to this internal factor of shafting torsional oscillation during signal Processing, weakening or eliminating are because of the preposition influence to signals of rotational speed sensor of signals of rotational speed sensor wheel, the difference dtsk ' of the adjacent cylinder split time that causes because of the torsional oscillation moment of torsion is deducted from total difference dtsk of adjacent cylinder split time, reach the purpose of the split time difference of twice ignition cylinder before and after reducing, thereby realize that shafting torsional oscillation was to the influence of the detection signal that catches fire when the elimination speed probe was preposition, thereby reduced each cylinder detection signal amplitude that catches fire, finally get rid of the interference that causes because of speed probe is preposition the measuring ability that catches fire, having reduced catches fire detects the background noise of demarcating, thereby reaches the purpose that improves the detection signal quality of catching fire.

Description of drawings

Below in conjunction with the drawings and the specific embodiments the present invention is described in further detail.

Fig. 1 is that speed probe of the present invention obtains the catch fire method one embodiment process flow diagram of detection signal of each cylinder of engine when preposition;

Fig. 2 is a process flow diagram of determining the method for the torsional vibration characteristic value between adjacent each cylinder.

Embodiment

The detection principle of catching fire of common automobile electronic fuel oil jet onboard diagnostic system (as the BOSCH system) is as follows:

When engine catches fire, because power interruption, cause the variation of engine crankshaft angular acceleration, and the variation of angular acceleration is directly proportional with the difference of two squares of rotating speed, split time by the individual cylinder of engine N (N is a positive integer) that speed probe is recorded, and then the detection signal luts that catches fire of definite each cylinder of engine

$\mathrm{luts}\left(0\right)=\frac{\mathrm{tsk}\left(0\right)-\mathrm{tsk}(N-1)}{\mathrm{tsk}{\left(0\right)}^3},$

$\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)}{\mathrm{tsk}{\left(i\right)}^3}---\left(1\right)$

I is integer and 1≤i≤N-1, luts (0) is the detection signal that catches fire of the 0th cylinder, luts (i) is the detection signal that catches fire of i cylinder, the split time of i the cylinder of engine that the split time of the 0th cylinder of engine that tsk (0) records for speed probe, tsk (i) record for speed probe;

By following formula as seen, to the interference of the detection signal that catches fire, conclude on the influence to the split time of each cylinder of engine in the time of can being installed in the engine belt pulley side to signals of rotational speed sensor wheel.

Each cylinder of engine does work respectively bent axle is produced periodic excitation, cause the torsional oscillation of engine shaft system, when the signals of rotational speed sensor wheel is installed in the engine belt pulley side, even at a steady state condition, the torsional oscillation of engine shaft system also can cause the not steady of signals of rotational speed sensor wheel running.Because driving source is from the acting of each cylinder of engine, therefore to show as with a working cycle be the cycle in this jiggly operation.

The above-mentioned detection principle of catching fire shows: the detection signal luts (i) that catches fire has reflected the crank shaft angle acceleration in i the pairing crankshaft angles of cylinder of engine interval, and the variation of any angular acceleration all is the result that engine torque changes, and the variation of the angular acceleration on the signals of rotational speed sensor wheel also is the result who acts on the variation of the engine torque above it.

When signals of rotational speed sensor wheel is installed in the engine belt pulley side, consider how the excitation of engine acting forms the torsional oscillation of axle system and then be reflected in the tach signal wheel and rotate if engine crankshaft is used as a flexible body, so will be very complicated.For simplifying modeling, engine crankshaft can be used as a rigid body, and the effect of torsional oscillation is simulated with a virtual torsional oscillation moment of torsion that comes out, certainly, this torsional oscillation moment of torsion is periodically variable with the acting of each cylinder of engine, and for a steady state condition, the signals of rotational speed sensor wheel angular acceleration that is caused by torsional oscillation is corresponding one by one with the torsional oscillation moment of torsion.

The modeling supposition: engine crankshaft is a rigid body; An extra torsional oscillation moment of torsion has caused the variation of signals of rotational speed sensor wheel angular acceleration under the steady state condition.

Based on above-mentioned modeling supposition, obtain following kinetics equation:

$M+W+\mathrm{\ΔM}=I\×\frac{\mathrm{d\ω}}{\mathrm{dt}}---\left(2\right)$

M is an engine torque, and W is the moment of resistance, and Δ M is the torsional oscillation moment of torsion, and I is the total moment of inertia of engine moving-mass, and ω is an angular velocity of crankshaft.

M+W=0 when generation is not caught fire in i cylinder normal operation of engine, formula (2) becomes:

$\frac{\mathrm{\ΔM}}{I}=\frac{\mathrm{d\ω}}{\mathrm{dt}}\∝\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)}{\mathrm{tsk}{\left(i\right)}^3}=\frac{\mathrm{dtsk}\left(i\right)}{\mathrm{tsk}{\left(i\right)}^3}---\left(3\right)$

The detection signal luts (i) that catches fire of i cylinder represents the running roughness of i cylinder of engine, and tsk (i) is the split time of i cylinder, and dtsk (i) is the total difference of the split time of i cylinder with the split time of i-1 the cylinder that is adjacent;

Luts (i) representative is under steady state condition in the formula (3), the size of the running roughness of i the cylinder of engine that causes by the torsional oscillation moment of torsion, computing formula according to luts (i), we obtain under same rotational speed (tsk (i) is identical) simultaneously, the torsional oscillation moment of torsion is directly proportional with the difference dtsk (i) of adjacent cylinder split time, therefore, the rule of research torsional oscillation moment of torsion can be set about from the difference dtsk (i) that studies adjacent cylinder split time.

When i cylinder of engine caught fire, engine torque M became 0, and resistance does not change apart from W, and preceding engine torque M is identical with catching fire, if this moment, moment of torsion Δ M was also constant, then had:

$W+\mathrm{\ΔM}=I\×\frac{\mathrm{d\ω}}{\mathrm{dt}}---\left(4\right)$

In the formula (4) It is the crank shaft angle acceleration in i cylinder i the pairing crankshaft angles of cylinder interval when catching fire;

$\frac{W}{I}=\frac{\mathrm{d\ω}}{\mathrm{dt}}-\frac{\mathrm{\ΔM}}{I}=\frac{\mathrm{d\ω}}{\mathrm{dt}}-\frac{d{\mathrm{\ω}}^{\′}}{\mathrm{dt}}---\left(5\right)$

Because

Substitution following formula (5):

$\frac{W}{I}-\frac{-M}{I}=\frac{\mathrm{d\ω}}{\mathrm{dt}}-\frac{d{\mathrm{\ω}}^{\′}}{\mathrm{dt}}\∝\frac{\mathrm{dtsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right)}{\mathrm{tsk}{\left(i\right)}^3}---\left(6\right)$

Dtsk ' (i) is the difference of the split time of same i-1 the cylinder that is adjacent of split time of i cylinder causing because of the torsional oscillation moment of torsion, from top derivation as can be seen, the variation of the crank shaft angle acceleration in i the pairing crankshaft angles of cylinder of the engine interval that wants that luts (i) signal can really be reflected and cause by catching fire, the split time that torsional oscillation must be caused in the definition of new luts (i) change deduction from total split time changes.

According to above-mentioned derivation, want to get rid of of the influence of engine torsional oscillation to detection signal luts (i) that catch fire of i cylinder of engine, allow luts (i) really reflect the variation of the crank shaft angle acceleration in i the pairing crankshaft angles of cylinder of the engine interval that causes by catching fire, just must from the total difference of split time with the split time of i-1 the cylinder that is adjacent of i cylinder, deduct with the difference of the split time of i-1 the cylinder that is adjacent the split time of i the cylinder that causes because of the torsional oscillation moment of torsion.And the variation of the difference of adjacent cylinder split time reflection moment of torsion, under normal steady state condition (nothing is caught fire), the difference of this adjacent cylinder split time (variation of moment of torsion in other words) has comprised the part that the engine torsional oscillation causes, has also comprised the part that each cylinder unevenness of engine causes.And it is actual when the signals of rotational speed sensor wheel is installed in the engine belt pulley side, the part that the engine cylinder uniformity causes is smaller, and the part that the engine torsional oscillation causes is main, just on this basis, we can be by research under normal steady state condition, and the difference of corresponding adjacent cylinder split time is studied the characteristic of engine torsional oscillation.

(a) the torsional oscillation moment of torsion is with the variation relation of engine load midmd

Signals of rotational speed sensor wheel is installed in engine belt pulley side project tests at a plurality of, the difference dtsk of each cylinder adjacent sectional time of corresponding engine under the different load condition under the statistics same rotational speed, this difference and the engine load linear relationship of finding each cylinder of engine are obvious, and torsional oscillation moment of torsion and the difference of adjacent sectional time are proportional, so can obtain such conclusion: the torsional oscillation intensity of engine (if representing with the torsional oscillation moment of torsion) is directly proportional with the load of engine.This point is readily appreciated that, because torsional oscillation is each cylinder acting of engine and the excitation that forms causes, the load of engine is big more, and it is strong more to do work, and the excitation of formation is also strong more, so the torsional oscillation intensity of engine is also high more.

(b) the torsional oscillation moment of torsion is with the variation relation of engine speed nmot

Since the torsional oscillation moment of torsion becomes the midmd proportional relation with the load of engine, the difference dtsk of each cylinder adjacent sectional time of corresponding engine can be studied afterwards the variation relation of the difference dtsk of each cylinder adjacent sectional time divided by engine load midmd with engine speed nmot.Test data analyzer shows, the value trend of dtsk*nmot/midmd on each operating point is consistent, that is to say, the difference dtsk of corresponding each cylinder adjacent sectional time under the same load condition with the engine speed nmot relation of being inversely proportional to, that is:

Can obtain by the relation of torsional oscillation moment of torsion and the difference dtsk of adjacent sectional time and the inverse relation of split time tsk and engine speed nmot:

$\mathrm{\ΔM}\∝\frac{\mathrm{dtsk}\left(i\right)}{\mathrm{tsk}{\left(i\right)}^3}\∝\frac{1}{\mathrm{tsk}{\left(i\right)}^3}\×\frac{1}{\mathrm{nmot}}\∝{\mathrm{nmot}}^2---\left(7\right)$

Formula (7) shows: under the certain situation of engine load, and square being directly proportional of engine torsional oscillation intensity and engine speed.

Since after engine structure is certain, torsional oscillation moment of torsion Δ M just shows fixing relation with the rotation speed n mot of engine and load midmd, and also there is following fixing relation in the difference dtsk ' of the adjacent sectional time that is caused by torsional oscillation moment of torsion Δ M with engine speed nmot and load midmd:

${\mathrm{dtsk}}^{\′}=K\×\frac{\mathrm{midmd}}{\mathrm{nmot}}---\left(8\right)$

K is the torsional vibration characteristic value between adjacent cylinder in the formula (8), only with relevant with engine structure, therefore can be by demarcation to the torsional vibration characteristic value between the adjacent cylinder of engine, the difference dtsk ' of corresponding adjacent sectional time of causing of reason torsional oscillation moment of torsion also on each operating point, it deducted from the detection signal luts that catches fire realizing, thereby the detection signal luts that catches fire to be reflected more accurately catch fire the variation of the angular acceleration that causes.According to conception before this, the improvement of the measuring ability that catches fire design should be set about from the calculating of the detection signal luts that catches fire, and the difference dtsk ' that will belong to the adjacent sectional time that the torsional oscillation moment of torsion causes deducts from total difference dtsk of adjacent sectional time.The computing formula of the detection signal luts (i) that catches fire of i cylinder of engine is as follows:

$\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{(\mathrm{tsk}\left(i\right)-\mathrm{dts}{k}^{\′}\left(i\right))}^3}=\frac{\mathrm{dtsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{(\mathrm{tsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right))}^3}---\left(9\right)$

In the formula (9), dtsk (i) is the total difference of the split time of i cylinder with the split time of i-1 the cylinder that is adjacent, dtsk ' (i) is the difference of the split time of same i-1 the cylinder that is adjacent of split time of i cylinder causing because of the torsional oscillation moment of torsion, and tsk (i) is the split time of i cylinder.

According to above analysis, comprise the 0th to N-1 adjacent in regular turn N (N is a positive integer)) engine of individual cylinder, the detection signal luts that catches fire of each cylinder of engine can obtain by the following method when speed probe was preposition, as shown in Figure 1:

One. demarcate the torsional vibration characteristic value between adjacent each cylinder of engine;

Two. split time tsk (the 0)～tsk (N-1) of each cylinder of speed probe detection of engine by being installed in the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that causes by the torsional oscillation moment of torsion,

${\mathrm{dtsk}}^{\′}\left(i\right)=K\left(i\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}}---\left(10\right)$

In the formula (10), i is positive integer and 1≤i≤N-1, and dtsk ' is the difference of the split time between same i-1 the cylinder of i cylinder (i), and K (i) is the torsional vibration characteristic value between same i-1 the cylinder of i cylinder, and midmd is an engine load, and nmot is an engine speed;

Four. calculate the detection signal that catches fire of each cylinder of output engine respectively,

The detection signal that catches fire of the 0th cylinder: $\mathrm{luts}\left(0\right)=\frac{\mathrm{tsk}\left(0\right)-\mathrm{tsk}(N-1)}{{\mathrm{tsk}}^3\left(0\right)},$

The detection signal that catches fire of i cylinder:

$\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{(\mathrm{tsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right))}^3}=\frac{\mathrm{dtsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{(\mathrm{tsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right))}^3}---\left(11\right)$

In the formula (11), tsk (i) is the split time of i cylinder, dtsk (i) is the total difference of the split time of i cylinder with the split time of i-1 cylinder being adjacent, and dtsk ' (i) is the difference of the split time of same i-1 the cylinder that is adjacent of split time of i cylinder causing because of the torsional oscillation moment of torsion.

Speed probe of the present invention obtains the catch fire method of detection signal of each cylinder of engine when preposition, the catch fire size of detection signal luts (i) of i cylinder is directly proportional with the difference of last cylinder split time with this cylinder split time, pay the utmost attention to this internal factor of shafting torsional oscillation during signal Processing, weakening or eliminating are because of the preposition influence to signals of rotational speed sensor of signals of rotational speed sensor wheel, the difference dtsk ' of the adjacent cylinder split time that causes because of the torsional oscillation moment of torsion is deducted from total difference dtsk of adjacent cylinder split time, reach the purpose of the split time difference of twice ignition cylinder before and after reducing, thereby realize that shafting torsional oscillation was to the influence of the detection signal that catches fire when the elimination speed probe was preposition, thereby reduced each cylinder detection signal amplitude that catches fire, finally get rid of the interference that causes because of speed probe is preposition the measuring ability that catches fire, having reduced catches fire detects the background noise of demarcating, thereby reaches the purpose that improves the detection signal quality of catching fire.

Speed probe of the present invention obtains the catch fire method of detection signal of each cylinder of engine when preposition, what consider is the split time variable quantity, think that the split time of the 0th cylinder is an absolutely accurate, other each cylinder is revised adjacent cylinder respectively, to be used to calculate each cylinder detection signal luts (characterizing crankshaft rotating angular velocity) that catches fire, finally reach purpose to the realization correction of the detection luts that catches fire.Each cylinder split time modified value is calculated and is seen formula (12), (13):

tskn(0)＝tsk(0)

tskn(1)＝tsk(1)-dtsk′(1)

tskn(2)＝tsk(2)-(dtsk′(1)+dtsk′(2))(12)

tskn(3)＝tsk(3)-(dtsk′(1)+dtsk′(2)+dtsk′(3))

${\mathrm{dtsk}}^{\′}\left(1\right)=K\left(1\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}}$

${\mathrm{dtsk}}^{\′}\left(2\right)=K\left(2\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}}---\left(13\right)$

${\mathrm{dtsk}}^{\′}\left(3\right)=K\left(3\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}}$

Tskn (i) representative is through the modified value of the split time of revised i the cylinder of torsional oscillation, tsk (i) represents the split time of i the cylinder that speed probe records, the split time that dtsk ' (i) represents i the cylinder that causes because of the torsional oscillation moment of torsion is with the difference of the split time of i-1 the cylinder that is adjacent, midmd is an engine load, nmot is an engine speed, and K (i) represents the torsional vibration characteristic value between i cylinder and the i-1 cylinder.

Torsional vibration characteristic value K between adjacent each cylinder can obtain by demarcation, and the torsional vibration characteristic value K between adjacent each cylinder can divide the Line tool that commentaries on classics is drawn a bow to the full by off-line to measure file and calculate, as shown in Figure 2, may further comprise the steps:

One. change the MAP working condition measuring of drawing a bow to the full, obtain repeatedly the split time of each cylinder under each operating mode, be recorded into each working condition measuring file respectively.The concrete operating mode of measuring is with the operating mode scope decision by detailed programs, be four cylinders now with engine, manual transmission, the signals of rotational speed sensor wheel is preposition, engine displacement 2.0 is upgraded to example explanation, it is rotating speed 2600rpm that MAP measures operating mode, 3200rpm, 3920rpm, 4600rpm, 5320rpm, each tachometric survey load is 26%, 34%, 42%, 51%, 60%, 70%, for ease of data processing, need guarantee to measure the sampled data and the sample frequency that will be used to analyze in the process of the test, and engine is normal stable the travelling more than 10 seconds of above-mentioned all operating modes, and 10 seconds left and right sides steady working condition can guarantee that this mean value can reflect the influence to split time that really brings because of speed probe is preposition;

Two. use the off-line analysis instrument, calculate under each operating mode each cylinder of engine with the mean difference of the split time between its last cylinder, computing method are that the split time to two adjacent cylinder under the same operating mode subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under the same operating mode, again to this under repeatedly same operating mode the difference of the split time of this two adjacent cylinder ask average and obtain the mean difference of the split time between this two adjacent cylinder under this operating mode, as under e kind operating mode

$\mathrm{dstke}\left(0\right)=\frac{\mathrm{dtsksume}\left(0\right)}{\mathrm{counte}\left(0\right)},\mathrm{dstke}\left(1\right)=\frac{\mathrm{dtsksume}\left(1\right)}{\mathrm{counte}\left(1\right)},......,\mathrm{dstke}\left(3\right)=\frac{\mathrm{dtsksume}\left(3\right)}{\mathrm{countd}\left(3\right)}---\left(14\right)$

In the formula (14), dtske (0) be under the e kind operating mode the 0th cylinder with the mean difference of the split time between its previous cylinder (i.e. the 3rd cylinder), dtske (i) be under the e kind operating mode the 1st cylinder with the mean difference of the split time between its previous cylinder (i.e. the 0th each cylinder), dtske (2) be under the e kind operating mode the 3rd cylinder with the mean difference of the split time between its previous cylinder (i.e. the 2nd cylinder), dtsksume (0) be under the e kind operating mode the 0th cylinder with the difference summation of the split time between its previous cylinder (i.e. the 3rd cylinder), dtsksume (1) be under the e kind operating mode the 1st cylinder with the difference summation of the split time between its previous cylinder (i.e. the 0th cylinder), dtsksume (3) be under the e kind operating mode the 3rd cylinder with the difference summation of the split time between its previous cylinder (i.e. the 2nd cylinder), counte (0) is total igniting number of times of the 0th cylinder under the e kind operating mode, counte (1) is total igniting number of times of the 1st cylinder under the e kind operating mode,, counte (3) is total igniting number of times of the 3rd cylinder under the e kind operating mode.

Three. calculate the torsional vibration characteristic value between each cylinder under the various operating modes,

$\mathrm{Ke}\left(i\right)=\frac{\mathrm{dtske}\left(i\right)*\mathrm{nmote}}{\mathrm{midmde}}---\left(15\right)$

In the formula (15), Ke (i) be under the e kind operating mode i cylinder with the torsional vibration characteristic value between its last cylinder, dtske (i) be under the e kind operating mode i cylinder with the mean difference of the split time between its previous cylinder, midmde is the engine load under the e kind operating mode, and nmote is the engine speed under the e kind operating mode;

Four: the torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged near this rule based on the torsional vibration characteristic value size between each cylinder under the various operating modes again, obtain the torsional vibration characteristic value K (0) between adjacent each cylinder, K (1), K (2), K (3); Then, consider that the improvement function is the split time based on the 0th cylinder, the split time of the 0th cylinder need not be revised, according to the torsional vibration characteristic value between adjacent each cylinder and should be 0 characteristic, the 0th cylinder revised the torsional vibration characteristic value that obtains between other final adjacent each cylinder with the torsional vibration characteristic value between other adjacent each cylinder outside the torsional vibration characteristic value between its previous cylinder.

For the automatic gear-box automobile, can consider wheel box two states (B_wk=1, lockup state; B_wk=0, lockup state not) carries out above-mentioned steps respectively, at the lockup state of automatic gear-box, do not measure repeatedly the split time of each cylinder under each operating mode under the lockup state two states respectively, obtain the torsional vibration characteristic value between each cylinder under the automatic gear-box two states respectively.

Claims (4)

1. obtain the catch fire method of detection signal of each cylinder of engine when a speed probe is preposition, engine comprises the 0th to N-1 N adjacent in regular turn cylinder, and N is a positive integer, it is characterized in that, may further comprise the steps:

One. demarcate the torsional vibration characteristic value between adjacent each cylinder of engine;

Two. split time tsk (the 0)～tsk (N-1) of each cylinder of speed probe detection of engine by being installed in the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that causes by the torsional oscillation moment of torsion,

${\mathrm{dtsk}}^{\′}\left(i\right)=K\left(i\right)*\frac{\mathrm{midmd}}{\mathrm{nmot}},$

I is positive integer and 1≤i≤N-1, and dtsk ' is the difference of the split time between same i-1 the cylinder of i cylinder (i), and K (i) is the torsional vibration characteristic value between same i-1 the cylinder of i cylinder, and midmd is an engine load, and nmot is an engine speed;

Four. calculate the detection signal that catches fire of each cylinder of output engine respectively,

The detection signal that catches fire of the 0th cylinder: $\mathrm{luts}\left(0\right)=\frac{\mathrm{tsk}\left(0\right)-\mathrm{tsk}(N-1)}{{\mathrm{tsk}}^3\left(0\right)}$

The detection signal that catches fire of i cylinder: $\mathrm{luts}\left(i\right)=\frac{\mathrm{tsk}\left(i\right)-\mathrm{tsk}(i-1)-{\mathrm{dtsk}}^{\′}\left(i\right)}{{[\mathrm{tsk}\left(i\right)-{\mathrm{dtsk}}^{\′}\left(i\right)]}^3}$

Tsk (i) is the split time of i cylinder.

2. speed probe according to claim 1 obtains the catch fire method of detection signal of each cylinder of engine when preposition, it is characterized in that, the torsional vibration characteristic value between adjacent each cylinder determines by the following method,

One. measure repeatedly the split time of each cylinder under each operating mode;

Two. calculate under each operating mode each cylinder of engine with the mean difference of the split time between its last cylinder, computing method are that the split time to two adjacent cylinder under the same operating mode subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under this operating mode, again to this repeatedly under this operating mode the difference of the split time of this two adjacent cylinder ask average and obtain the mean difference of the split time between this two adjacent cylinder under this operating mode;

Three. calculate the torsional vibration characteristic value between each cylinder under the various operating modes,

$\mathrm{Ke}\left(i\right)=\frac{\mathrm{dtske}\left(i\right)*\mathrm{nmote}}{\mathrm{midmde}}$

Ke (i) be under the e kind operating mode i cylinder with the torsional vibration characteristic value between its last cylinder, dtske (i) be under the e kind operating mode i cylinder with the mean difference of the split time between its previous cylinder, midmde is the engine load under the e kind operating mode, and nmote is the engine speed under the e kind operating mode;

Four. the torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged, obtain the torsional vibration characteristic value between adjacent each cylinder.

3. speed probe according to claim 2 obtains the catch fire method of detection signal of each cylinder of engine when preposition, it is characterized in that, torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged, obtain the torsional vibration characteristic value between adjacent each cylinder, then according to the torsional vibration characteristic value between adjacent each cylinder and should be 0 characteristic, the 0th cylinder revised the torsional vibration characteristic value that obtains between other final adjacent each cylinder with the torsional vibration characteristic value between other adjacent each cylinder outside the torsional vibration characteristic value between its previous cylinder.

4. speed probe according to claim 2 obtains the catch fire method of detection signal of each cylinder of engine when preposition, it is characterized in that, for the automatic gear-box automobile, at the lockup state of automatic gear-box, do not measure repeatedly the split time of each cylinder under each operating mode under the lockup state two states respectively, obtain the torsional vibration characteristic value between each cylinder under the automatic gear-box two states respectively.

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