CN102072818B - 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 method for each cylinder fire detection signal of engine when speed probe is preposition

Technical field

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

Background technology

definition according to relevant onboard diagnostic system (OBD) in the existing light-duty vehicle pollutant emission limit of China and measuring method (GB18352.3-2005), catching fire, to detect be important component part in the OBD system, automobile factory must state when declaring the type of vehicle authentication and determine to cause discharging the fire loss ratio when exceeding standard and cause the overheated fire loss ratio that causes irreversible damage of exhaust catalyst converter because 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, to guarantee to be mistaken for when vehicle operating is normal to catch 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 there are larger difference in processing and the computing method of signals of rotational speed sensor, therefore correctly whether catch fire speed probe to detect original signal (crankshaft rotating fluctuation) be the condition precedent that is related to the fire detection signal accuracy by perception, thereby be directly connected to the quality of match of the detection of catching fire.

Installation site about speed probe, normally be arranged on engine flywheel end (clutch end), reason is that signals of rotational speed sensor wheel is contained in the flywheel side and near flywheel, because 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 the torsional oscillation of engine and kinematic train exists, can descend than being contained in its stationarity of flywheel end, thereby can affect 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 arranged on the engine belt pulley end, the torsional oscillation of engine and kinematic train can be unfavorable greatly to the mass formation of fire detection signal like this, the fire detection signal quality can descend, particularly in high rotating speed, the inadequate situation of relevant self study (self study of signal gear teeth deviation, fuel feeding self study are namely to the inhomogeneity self study of each cylinder burning), can not guarantee good fire detection signal quality.

Present many signals of rotational speed sensor wheels are arranged on the vehicle of engine belt pulley end, its be generally by the controlled working precision reduce engine and Torsional Vibration of Shafts to the fire detection signal quality influence, 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 is to provide a kind of method that speed probe obtains each cylinder fire detection signal of engine when preposition, when the signals of rotational speed sensor wheel is arranged on pulley end, still can provide fire detection signal accurately.

For solving the problems of the technologies described above, speed probe of the present invention obtains the method for each cylinder fire detection signal of engine when preposition, and engine comprises the 0th to N-1 adjacent N cylinder sequentially, and N is positive integer, comprises the following steps:

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

Two. detect the split time tsk (0) of each cylinder of engine～tsk (N-1) by the speed probe that is arranged on the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that is caused 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 (i) difference of the split time between same i-1 the cylinder of i cylinder, and K (i) is the torsional vibration characteristic value between same i-1 the cylinder of i cylinder, and midmd is engine load, and nmot is engine speed;

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

The fire detection signal 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 fire detection signal 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 same operating subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under this operating mode, then to this repeatedly under this operating mode the difference of the split time of this two adjacent cylinder be averaging 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 various operating modes,

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

Ke (i) be under e kind operating mode the i cylinder with the torsional vibration characteristic value between its last cylinder, dtske (i) be under e kind operating mode i cylinder with the mean difference of the split time between its previous cylinder, midmde is the engine load under e kind operating mode, and nmote is the engine speed under 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 respectively repeatedly the split time of each cylinder under each operating mode under the lockup state two states, obtain respectively the torsional vibration characteristic value between each cylinder under the automatic gear-box two states.

speed probe of the present invention obtains the method for each cylinder fire detection signal of engine when preposition, the size of i cylinder fire detection signal luts (i) is directly proportional to the difference of last cylinder split time to this cylinder split time, when processing, signal pays the utmost attention to this internal factor of shafting torsional oscillation, weaken or get rid of because of the preposition impact on 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 poor purpose of split time of twice ignition cylinder before and after reducing, thereby realize the impact of shafting torsional oscillation on fire detection signal when the elimination speed probe is preposition, thereby reduced each cylinder fire detection signal amplitude, finally get rid of the interference that causes because speed probe is preposition the measuring ability that catches fire, having reduced catches fire detects the background noise of demarcating, thereby reach the purpose that improves the fire detection signal quality.

Description of drawings

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

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

Fig. 2 is the 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, due to power interruption, cause the variation of engine crankshaft angular acceleration, and the variation of angular acceleration is directly proportional to the difference of two squares of rotating speed, split time by the individual cylinder of engine N (N is positive integer) that speed probe is recorded, and then the fire detection signal luts 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 fire detection signal of the 0th cylinder, luts (i) is the fire detection signal 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 fire detection signal, conclude on the impact on the split time of each cylinder of engine in the time of can being arranged on 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 arranged on the engine belt pulley side, even at a steady state condition, the torsional oscillation that engine shaft is also can cause the not steady of signals of rotational speed sensor wheel running.Due to the acting of driving source from each cylinder of engine, therefore this jiggly operation shows as take a working cycle as the cycle.

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

When signals of rotational speed sensor wheel is arranged on 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, will be very complicated so.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 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 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 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 fire detection signal luts (i) of i cylinder represents the running roughness of i cylinder of engine, tsk (i) is the split time of i cylinder, and dtsk (i) is that the split time of i cylinder is with total difference of the split time of i-1 the cylinder that is adjacent;

In formula (3), luts (i) representative is under steady state condition, the size of the running roughness of i the cylinder of engine that is caused 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 to 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 front engine torque M is identical with catching fire, if this moment, moment of torsion Δ M was also constant, had:

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

In formula (4)

It is the crank shaft angle acceleration in i cylinder i the corresponding crankshaft angles of cylinder interval when catching fire;

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

Due to

Substitution following formula (5):

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

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

According to above-mentioned derivation, want to get rid of the engine torsional oscillation to the impact of the fire detection signal luts (i) of i cylinder of engine, allow the variation of crank shaft angle acceleration in i, engine that the real reflection of luts (i) causes by the catching fire corresponding crankshaft angles of cylinder interval, deduct total difference of the split time of i-1 the cylinder that just must be adjacent the split time of i the cylinder that causes because of the torsional oscillation moment of torsion together from the split time of i cylinder with the difference of the split time of i-1 the cylinder that is adjacent.And the variation of the difference of adjacent cylinder split time reflection moment of torsion, under normal steady state condition (without catching 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 arranged on 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 arranged on engine belt pulley side project tests for 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 larger, does work stronger, and the excitation of formation is also stronger, so the torsional oscillation intensity of engine is also higher.

(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 difference dtsk of each cylinder adjacent sectional time divided by engine load midmd with the variation relation of 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 that is inversely proportional to, that is:

Can be obtained 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: in the situation that engine load is certain, 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:

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

In formula (8), K is the torsional vibration characteristic value between adjacent cylinder, only with relevant with engine structure, therefore can be by the 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 fire detection signal luts realizing, thereby fire detection signal luts 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 fire detection signal luts, 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 fire detection signal luts (i) 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 formula (9), dtsk (i) is that the split time of i cylinder is with total difference of the split time of i-1 the cylinder that is adjacent, the difference of the split time of i-1 the cylinder that dtsk ' (i) is adjacent together for the split time of i cylinder causing because of the torsional oscillation moment of torsion, tsk (i) is the split time of i cylinder.

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

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

Two. detect the split time tsk (0) of each cylinder of engine～tsk (N-1) by the speed probe that is arranged on the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that is caused 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 formula (10), i is positive integer and 1≤i≤N-1, and dtsk ' is (i) difference of the split time between same i-1 the cylinder of i cylinder, and K (i) is that i cylinder is with the torsional vibration characteristic value between i-1 cylinder, midmd is engine load, and nmot is engine speed;

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

The fire detection signal 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 fire detection signal 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 formula (11), tsk (i) is the split time of i cylinder, dtsk (i) be the split time of i cylinder with total difference of the split time of i-1 cylinder being adjacent, the difference of the split time of i-1 the cylinder that dtsk ' (i) is adjacent together for the split time of i cylinder causing because of the torsional oscillation moment of torsion.

speed probe of the present invention obtains the method for each cylinder fire detection signal of engine when preposition, the size of i cylinder fire detection signal luts (i) is directly proportional to the difference of last cylinder split time to this cylinder split time, when processing, signal pays the utmost attention to this internal factor of shafting torsional oscillation, weaken or get rid of because of the preposition impact on 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 poor purpose of split time of twice ignition cylinder before and after reducing, thereby realize the impact of shafting torsional oscillation on fire detection signal when the elimination speed probe is preposition, thereby reduced each cylinder fire detection signal amplitude, finally get rid of the interference that causes because speed probe is preposition the measuring ability that catches fire, having reduced catches fire detects the background noise of demarcating, thereby reach the purpose that improves the fire detection signal quality.

Speed probe of the present invention obtains the method for each cylinder fire detection signal of engine when preposition, what consider is the split time variable quantity, think that the split time of the 0th cylinder is absolutely accurate, other each cylinder is revised adjacent cylinder respectively, to be used for calculating each cylinder fire detection signal luts (characterizing crankshaft rotating angular velocity), finally reach the 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, dtsk ' (i) represents that the split time of 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 engine load, nmot is engine speed, and K (i) represents the torsional vibration characteristic value between i cylinder and 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 to calculate turning the measurement file of drawing a bow to the full by off-line, as shown in Figure 2, comprises the following steps:

One. turn 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 respectively each working condition measuring file.concrete Test Cycle determines with the condition range by detailed programs, now take engine as four cylinders, manual transmission, the signals of rotational speed sensor wheel is preposition, engine displacement 2.0 is upgraded to example explanation, the MAP Test Cycle is rotating speed 2600rpm, 3200rpm, 3920rpm, 4600rpm, 5320rpm, each tachometric survey load is 26%, 34%, 42%, 51%, 60%, 70%, process for ease of data, need guarantee to measure sampled data and the sample frequency that will be used for analysis in process of the test, and engine is normal stable the travelling more than 10 seconds of above-mentioned all operating modes, 10 seconds left and right steady working condition can guarantee that this mean value can reflect the impact on split time that really brings because 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 same operating subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under same operating, again to this repeatedly under same operating the difference of the split time of this two adjacent cylinder be averaging 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 formula (14), dtske (0) be under 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 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 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 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 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 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 e kind operating mode, counte (1) is total igniting number of times of the 1st cylinder under e kind operating mode, counte (3) is total igniting number of times of the 3rd cylinder under e kind operating mode.

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

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

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

Four: again based on the torsional vibration characteristic value size between each cylinder under various operating modes near this rule, torsional vibration characteristic value between the adjacent cylinder under each operating mode is averaged, obtain the torsional vibration characteristic value K (0) between adjacent each cylinder, K (1), K (2), K (3); Then, consider that improving function is that split time take the 0th cylinder is as the basis, 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) carry out respectively above-mentioned steps, at the lockup state of automatic gear-box, do not measure respectively repeatedly the split time of each cylinder under each operating mode under the lockup state two states, obtain respectively the torsional vibration characteristic value between each cylinder under the automatic gear-box two states.

Claims (4)

1. obtain the method for each cylinder fire detection signal of engine when a speed probe is preposition, engine comprises the 0th to N-1 adjacent N cylinder sequentially, and N is positive integer, it is characterized in that, comprises the following steps:

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

Two. detect the split time tsk (0) of each cylinder of engine～tsk (N-1) by the speed probe that is arranged on the engine belt pulley end;

Three. calculate the difference of the split time of adjacent each cylinder that is caused 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 (i) difference of the split time between same i-1 the cylinder of i cylinder, and K (i) is the torsional vibration characteristic value between same i-1 the cylinder of i cylinder, and midmd is engine load, and nmot is engine speed;

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

The fire detection signal 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 fire detection signal 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. obtain the method for each cylinder fire detection signal of engine when speed probe according to claim 1 is preposition, it is characterized in that, the 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 same operating subtracts each other, obtain repeatedly the difference of the split time of this two adjacent cylinder under this operating mode, then to this repeatedly under this operating mode the difference of the split time of this two adjacent cylinder be averaging 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 various operating modes,

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

Ke (i) be under e kind operating mode the i cylinder with the torsional vibration characteristic value between its last cylinder, dtske (i) be under e kind operating mode i cylinder with the mean difference of the split time between its previous cylinder, midmde is the engine load under e kind operating mode, and nmote is the engine speed under 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. obtain the method for each cylinder fire detection signal of engine when speed probe according to claim 2 is 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. obtain the method for each cylinder fire detection signal of engine when speed probe according to claim 2 is preposition, it is characterized in that, for the automatic gear-box automobile, at the lockup state of automatic gear-box, do not measure respectively repeatedly the split time of each cylinder under each operating mode under the lockup state two states, obtain respectively the torsional vibration characteristic value between each cylinder under the automatic gear-box two states.

Images