CN101059106A - Misfire detecting device of internal combustion engine - Google Patents

Abstract

To provide a misfire detecting device of an internal combustion engine which can accurately determine the misfire of each cylinder by relatively easy computing, and which has high general versatility. A deviation between a standard rotation speed OMGR ((k-1)NTDC) and a rotation speed parameter (OMGR(i)) is calculated as a relative rotation speed OMGREF(i) (S12, S13). The standard rotation speed OMGR is detected near a compression top dead center of each cylinder, and the rotation speed parameter (OMGR(i)) is detected on a predetermined crank angle. Then an inertial force rotation speed OMGI(k) is calculated which indicates the speed component caused by the inertial force of the reciprocating motion part or the like of the internal combustion engine (S14). The relative rotation speed OMGREF(i) is modified by this, and the modified relative rotation speed OMGREFM(i) is calculated (S15). By the summation of the modified relative rotation speed OMGREFM(i), a determination parameter MFJUD(k) is calculated (S16), and misfire determination is made based on the judgement parameter MFJUD (S17).

Description

The misfire detecting apparatus of internal-combustion engine

Technical field

The present invention relates to the misfire detecting apparatus of internal-combustion engine, particularly judge the device that catches fire and have or not according to the rotary speed parameter corresponding with internal-combustion engine rotational speed.

Background technique

In patent documentation 1, disclosed according to split time and formed characteristic signal q (n) as the rotation needed time of regulation crank shaft angle, judge the method for catching fire and having or not according to this characteristic signal q (n).Characteristic signal q (n) is the signal of expression split time, is to be converted into the signal that illustrates as the point on the complex plane, judges having or not of catching fire according to size and the phase place of characteristic signal q (n).

Patent documentation 1: Japanese kokai publication hei 9-119338 communique

In above-mentioned method in the past, need be from expression as the band-pass filter that extracts desired frequency content the signal of the split time of rotary speed parameter, and need to change filbter characteristic according to the pattern of catching fire that should detect (for example, 1 cylinder catches fire continuously, relative 2 cylinders catch fire continuously etc. the generation form of catching fire).Therefore, exist misfire determining to handle complicated problem.

And existence can't be judged exactly at which cylinder, and the situation of catching fire has taken place, and exists along with the number of cylinders of internal-combustion engine contents processing to change or the required many problems in man-hour of setting of decision threshold.

Summary of the invention

The present invention proposes in order to address the above problem, and its purpose is to provide a kind of can carry out misfire determining and the high misfire detecting apparatus of versatility accurately to each cylinder by fairly simple computing.

In order to reach above-mentioned purpose, the misfire detecting apparatus of the internal-combustion engine of a first aspect of the present invention, this misfire detecting apparatus has the rotary speed parameter detection unit (12,20) that detects the rotary speed parameter (OMG) corresponding with the rotating speed of internal-combustion engine, (OMG) detects catching fire of described internal-combustion engine according to detected rotary speed parameter, it is characterized in that, have: the reference value computing unit, it calculates the reference value (OMGR ((k-1) NTDC)) of described rotary speed parameter; The relative velocity parameter calculation unit, it calculates described reference value (OMGR ((k-1) NTDC)) and the deviation between the regulation detected rotary speed parameter of crank shaft angle (OMGR (i)) as relative velocity parameter (OMGREF (i), OMGREFM (i)); And identifying unit, it calculates the aggregate-value (MFJUD) of described relative velocity parameter, carries out misfire determining according to the aggregate-value (MFJUD) of this calculating.

The internal-combustion engine misfire detecting apparatus of second aspect present invention, it is characterized in that, in the misfire detecting apparatus of the internal-combustion engine of a first aspect of the present invention, described reference value (OMGR ((k-1) NTDC)) is near the piston that becomes the cylinder of a misfire determining object detected described rotary speed parameter when being positioned at the compression top dead center.

The internal-combustion engine misfire detecting apparatus of third aspect present invention, it is characterized in that, of the present invention first or the misfire detecting apparatus of the internal-combustion engine of second aspect in, described identifying unit adds up described relative velocity parameter (OMGREF (i), OMGREFM (i)) in during crank shaft angle 720/N (N is the cylinder number of described internal-combustion engine) degree.

At this, as the influence of the burning that is not vulnerable to other cylinder and comprise take place in the combustion stroke of associated cylinder (judging the object cylinder) moment of torsion for maximum crank shaft angle position during, carry out described accumulative total the 720/N degree during, for example, be set at during near the 720/N degree of the beginning beginning upper dead center (compression top dead center) of the combustion stroke of this cylinder.

The internal-combustion engine misfire detecting apparatus of fourth aspect present invention, it is characterized in that, in of the present invention first the misfire detecting apparatus of each described internal-combustion engine to the third aspect, also has inertial force speed composition computing unit, it calculates the inertial force rotating speed composition (OMGI) that the inertial force by the movable member of described internal-combustion engine causes, described identifying unit carries out described misfire determining according to described relative velocity parameter (OMGREF (i), OMGREFM (i)) and inertial force rotating speed composition (OMGI).

The internal-combustion engine misfire detecting apparatus of fifth aspect present invention, it is characterized in that, in of the present invention first the misfire detecting apparatus of each described internal-combustion engine to the third aspect, also has inertial force speed composition computing unit, it calculates the inertial force rotating speed composition (OMGIa) that the inertial force by the movable member of described internal-combustion engine causes, described identifying unit is revised described relative velocity parameter (OMGREF) with described inertial force rotating speed composition (OMGIa), thereby calculate the 1st and revise relative velocity parameter (OMGREFMa), the burning correlation function (FCR) that rotation speed change when revising relative velocity parameter (OMGREFMa) and multiply by normal combustion the 1st is similar to, calculate the 2nd and revise relative velocity parameter (OMGREFMb), carry out described misfire determining according to the 2nd integral value (MFJUDd) of revising the relative velocity parameter.

The internal-combustion engine misfire detecting apparatus of sixth aspect present invention is characterized in that, in the misfire detecting apparatus of the described internal-combustion engine of a fifth aspect of the present invention, described burning correlation function (FCR) is defined by following formula:

(1-2cos(N·θ/2))/2

Wherein, N is the cylinder number of described internal-combustion engine, and θ is that the angle that the piston with the specific cylinder of described internal-combustion engine is positioned at the upper dead center position place is the crank shaft angle of benchmark.

The internal-combustion engine misfire detecting apparatus of seventh aspect present invention, it is characterized in that, in the misfire detecting apparatus of the described internal-combustion engine of a fifth aspect of the present invention, described burning correlation function (FCR) is that the rotation speed change waveform with the normal combustion state of described internal-combustion engine is normalized into minimum value and is " 0 " and the maximum value function for " 1 ".

The internal-combustion engine misfire detecting apparatus of eighth aspect present invention, it is characterized in that, in the misfire detecting apparatus of each the described internal-combustion engine in aspect of the present invention first to fourth, also possesses the load torque correcting unit, it is proofreaied and correct described rotary speed parameter (OMG (i)), the rotating speed variance components that the moment of torsion that applies to described internal-combustion engine because of the load side from described internal-combustion engine with eliminating causes, rotary speed parameter (OMGR (i)) after described reference value computing unit and the utilization of relative velocity parameter calculation unit are proofreaied and correct by described load torque correcting unit carries out the calculating and the described relative velocity CALCULATION OF PARAMETERS of described reference value respectively.

At this, " moment of torsion that applies to described internal-combustion engine from the load side of described internal-combustion engine " is meant particularly by the wheel of oil-engine driven vehicle or subsidiary engine or because the friction of internal-combustion engine and moment of torsion that internal-combustion engine is applied.

According to a first aspect of the invention, calculate the reference value of rotary speed parameter, calculate described reference value and the deviation between the detected rotary speed parameter of regulation crank shaft angle as the relative velocity parameter, carry out misfire determining according to the aggregate-value that this relative velocity parameter is added up to obtain.By suitably setting reference value, the aggregate-value of relative velocity parameter is represented the generation moment of torsion of the cylinder in the combustion stroke, therefore, according to this aggregate-value, can judge in the cylinder that moment of torsion is a negative value takes place and take place to catch fire.This judgement is carried out each cylinder, no matter therefore how many cylinder number of internal-combustion engine is, the generation cylinder of all can easily determining to catch fire.Its result can carry out accurately misfire determining and can carry out the high misfire determining of versatility by fairly simple computing.

According to a second aspect of the invention, reference value is near piston as the cylinder of a misfire determining object detected rotary speed parameter when being positioned at the compression top dead center.Thus, can judge according to the passing of the combustion stroke medium speed parameter of object cylinder.

According to a third aspect of the invention we, in during crank shaft angle 720/N (N is the cylinder number of described internal-combustion engine) degree, the relative velocity parameter is added up, and calculate aggregate-value.The 720/N degree be equivalent to the corresponding crank shaft angle of the generating period of combustion stroke during, by in this period, adding up, can carry out misfire determining accurately to each cylinder.

According to a forth aspect of the invention, the inertial force rotating speed that causes according to the inertial force of the movable member of relative velocity parameter and internal-combustion engine becomes to assign to carry out misfire determining.Thus, can get rid of the influence of the rotating speed composition that the inertial force of the movable member of internal-combustion engine causes, judge accurately.

According to a fifth aspect of the invention, with inertial force rotating speed composition the relative velocity parameter is revised, thereby calculate the 1st and revise the relative velocity parameter, the burning correlation function (FCR) that rotation speed change when revising the relative velocity parameter and multiply by normal combustion the 1st is similar to calculates the 2nd and revises the relative velocity parameter, carries out misfire determining according to the 2nd integral value of revising the relative velocity parameter.By multiply by the burning correlation function, can remove the influence that is included in the interference in the detected rotary speed parameter, improve the precision of misfire determining.

According to a sixth aspect of the invention, use the burning correlation function of the above-mentioned formula definition of having used cosine function, can carry out suitable correction by fairly simple computing, and irrelevant with cylinder number.

According to a seventh aspect of the invention, as the application of burning correlation function the rotation speed change waveform under the normal combustion state of internal-combustion engine being normalized into minimum value is the function of " 1 " for " 0 " and maximum value, therefore the characteristic of internal-combustion engine can be in the burning correlation function, reflected, more suitable correction can be carried out.

According to an eighth aspect of the invention, rotary speed parameter is proofreaied and correct, the rotating speed variance components that the moment of torsion that applies because of the load side from internal-combustion engine with eliminating causes, utilize the rotary speed parameter after this correction, carry out the calculating and the relative velocity CALCULATION OF PARAMETERS of reference value, thereby can get rid of the influence of the rotating speed variance components that causes because of the load torque that is applied on the internal-combustion engine, judge accurately.

Description of drawings

Fig. 1 is the figure of the structure of expression internal-combustion engine of an embodiment of the invention and control gear thereof.

Fig. 2 is the figure that is used to illustrate the method for misfire determining.

Fig. 3 is the figure of expression passing of parameters calculated for misfire determining.

Fig. 4 is the figure of expression passing of parameters calculated for misfire determining.

Fig. 5 is the figure that is used to illustrate the computational methods of the inertial force moment of torsion that is caused by the reciprocating member work of motor.

Fig. 6 is the oscillogram of the relation of the synthetic inertia torque (TI) of inertial force moment of torsion (TI1), 6 cylinders of each cylinder of expression and corresponding inertial force rotating speed (ω I).

Fig. 7 is the flow chart that the misfire determining of first mode of execution is handled.

Fig. 8 is the figure of the example of expression result of determination.

Fig. 9 is the flow chart that the misfire determining of the variation of first mode of execution is handled.

Figure 10 is the flow chart that the misfire determining of second mode of execution is handled.

Figure 11 is the flow chart that the misfire determining of the variation of second mode of execution is handled.

Figure 12 is used for illustrating the figure that exports the influence of the interference that comprises in crank angle position sensor.

Figure 13 is the figure of the example of expression burning correlation function (FCR).

Figure 14 is the figure of another example of expression burning correlation function (FCR).

Figure 15 be expression misfire determining parameter measured value deviation figure.

Figure 16 is the flow chart that the misfire determining of the 3rd mode of execution of the present invention is handled.

Embodiment

Below, with reference to accompanying drawing embodiments of the present invention are described.

[first mode of execution]

Fig. 1 is the figure of the structure of expression internal-combustion engine of an embodiment of the invention and control gear thereof.Internal-combustion engine (hereinafter referred to as " motor ") 1 for example has 6 cylinders, possesses suction tude 2 and outlet pipe 5.In suction tude 2, be provided with closure 3.And in outlet pipe 5, be provided with the catalyst 6 that carries out exhaust gas purification.

Be provided with Fuelinjection nozzle 4 for each cylinder, its be located between motor 1 and the closure 3 and be positioned at suction tude 2 not shown intake valve slightly by upstream side, each injection valve is connected with not shown petrolift, and be electrically connected with electronic control unit (hereinafter referred to as " ECU ") 20, by control the opening time of Fuelinjection nozzle 4 from the control signal of ECU 20.

Absolute pressure (PBA) sensor 11 in the downstream part near closure 3 is provided with the suction tude that detects the pressure in the suction tude 2 provides its testing signal to ECU 20.

On ECU 20, be connected with the crank angle position sensor 12 of angle of swing of the bent axle (not shown) of detection of engine 1, provide the signal corresponding to ECU 20 with the angle of swing of bent axle.Crank angle position sensor 12 is made of following sensor: the cylinder discrimination sensor, and it is in the output pulse (hereinafter referred to as " CYL pulse ") of the regulation crank angle position place of the specific cylinder of motor 1; Crank angle position place (in 6 cylinder engines, being per 120 degree of crank shaft angle) the output TDC pulse before the regulation crankshaft angles of TDC sensor, the upper dead center (TDC) when its suction stroke about each cylinder begins; And the CRK sensor, it produces 1 pulse (hereinafter referred to as " CRK pulse ") according to certain crank shaft angle cycle (for example 6 spend the cycle) shorter than TDC pulse, provides CYL pulse, TDC pulse and CRK pulse to ECU 20.These pulses are used for the various timing controls of fuel injection timing, ignition timing etc., the detection of engine speed (engine rotary speed) NE.And ECU 20 carries out the detection of catching fire of motor 1 according to time of origin interval (hereinafter referred to as " time parameter ") CRME of CRK pulse.

ECU 20 is by constituting with the bottom: input circlult, and it has the waveform input signal from various sensors is carried out shaping, and voltage level is modified to the level of regulation, analog signal values is converted to the function of digital signal value etc.; Central processing unit (hereinafter referred to as " CPU "); The memory circuit of various operation programs that storage is carried out by CPU and operation result etc.; And provide output circuit of control signal etc. to Fuelinjection nozzle 4 etc.The CPU of ECU 20 carries out the detection of catching fire of following explanation.

Then the method that detects of catching fire to present embodiment at length describes.

Near Fig. 2 (a) detected rotating speed (hereinafter referred to as " reference rotation speed ") that is expression with the Piston Compression upper dead center of each cylinder of motor 1 time is the sequential chart of passing of the relative rotation speed OMGREF of benchmark.Compression top dead center is defined as the upper dead center that the combustion stroke of each cylinder begins.In addition, in the following description, " compression top dead center of each cylinder " or " near the compression top dead center of each cylinder " is meant " when the piston of each cylinder is in compression top dead center " or " piston of each cylinder be in compression top dead center near time ".Calculate relative rotation speed OMGREF by deducting reference rotation speed the rotating speed (calculating) that detects from crankshaft angles according to time parameter CRME every 6 degree.#1～#6 among Fig. 2 (a) is the cylinder identiflication number (different with cylinder numbers described later) that adds in order according to the order of igniting 6 cylinders to be discerned.In the combustion stroke after compression top dead center, if igniting normally carries out, then relative rotation speed OMGREF be on the occasion of, be negative value if catch fire then.That is, in the example shown in Fig. 2 (a), #1～#3, #5 and #6 cylinder carry out normal combustion, and have taken place to catch fire in the #4 cylinder.Therefore, shown in the bar graph (bar graph that does not add hatched right side) of Fig. 2 (b), is negative value by accumulative total in during 1 TDC (during the corresponding crankshaft angles of combustion stroke 120 degree) in the #4 cylinder that the aggregate-value that the relative rotation speed OMGREF that crank shaft angle 6 degree calculate obtains is catching fire, in the cylinder that carries out normal combustion be on the occasion of.Thus, the decidable cylinder that catches fire.And the aggregate-value that obtains by above-mentioned computing becomes the parameter that is illustrated in the moment of torsion that takes place in each cylinder.

Shown in Fig. 2 (b) add hatched bar charts be shown in during 1 TDC in to near the detected time parameter compression top dead center (hereinafter referred to as " parameter fiducial time ") being the aggregate-value that the relative time parameters C RMEREF of benchmark adds up to obtain.Calculate relative time parameters C RMEREF by deduct the time parameter that detects every crank shaft angle 6 degree the parameter from fiducial time.That is, if by burning moment of torsion takes place, then relative time parameters C RMEREF be on the occasion of, then be negative value if moment of torsion takes place because of catching fire.Thus, same with the aggregate-value of relative rotation speed OMGREF, the aggregate-value of relative time parameters C RMEREF is a negative value at the #4 cylinder that catches fire, in the cylinder that carries out normal combustion on the occasion of.Thus, time parameter CRME is not converted to rotating speed OMG and directly uses the judgement of the cylinder that can catch fire equally.

Fig. 3 and Fig. 4 are the sequential charts that is used for illustrating in further detail above-mentioned misfire determining method.Fig. 3 and Fig. 4 represent the state that engine speed NE is rising.The passing of Fig. 3 (a) express time parameters C RME, Fig. 3 (b) expression is by the passing of the rotating speed OMG of time parameter CRME calculating.Fig. 3 (c) represents the passing by rotating speed OMGR after the Shelving that rotating speed OMG enforcement 720 degree Shelving are calculated.Linear change composition in during 720 degree Shelving 1 cycles of elimination, the processing (the details aftermentioned of this processing) of the more short-period change of extraction.720 degree Shelving are in order to remove the processing that rotation variance components that the moment of torsion that applied to motor 1 by the load side from motor 1 (tire of the vehicle that drives by motor 1 or the moment of torsion that subsidiary engine applies, the perhaps moment of torsion that causes owing to the friction of the slide member of motor 1) causes carries out.

Fig. 4 (a) is illustrated near the compression top dead center of each cylinder, the passing of the inertial force rotating speed OMGI that calculates with the timing identical with the calculating of reference rotation speed.Moment of inertia according to the rotary component of the load side of the motor 1 of length, crank throw and the crankshaft pulley of the quality of the reciprocating member (piston and connecting rod) of motor 1, connecting rod, torque-converters, lock-up clutch etc. calculates inertial force rotating speed OMGI.

Correction relative rotation speed OMGREFM by relative rotation speed OMGREF being added inertial force rotating speed OMGI and calculate of Fig. 4 (b) expression (=OMGREF+OMGI) passing, Fig. 4 (c) expression by in during 1 TDC to revising aggregate-value that relative rotation speed OMGREFM adds up to calculate, being the passing of critical parameter MFJUD.In this embodiment, critical parameter MFJUD is a negative value in the scope of crank shaft angle 120 degree～240 degree, is judged to be at the #2 cylinder and has taken place to catch fire.

The computational methods of inertial force rotating speed OMGI then, are described.If the angular velocity of rotation that establishing length of connecting rod as shown in Figure 5 and be L, crank throw is R, be biased to e, bent axle is that the total quality of ω, piston and connecting rod is m, angle θ and φ are according to pictorial definition, and then the moment of torsion that is caused by the inertial force that produces in 1 cylinder (hereinafter referred to as " single cylinder inertia torque ") TI1 can use following formula (1) expression.Wherein, the unit of the angle in the formula shown below is made as and uses radian [rad].

$\mathrm{<figure-callout\; id="1"\; label="TI"\; filenames="A20061016455800221.png,A20061016455800222.png"\; state="\{\{state\}\}">TI</figure-callout>}1=-\mathrm{<figure-callout\; id="2"\; label="m\; R"\; filenames="A20061016455800221.png,A20061016455800222.png"\; state="\{\{state\}\}">m</figure-callout>}{R}^{}{}^2{\mathrm{\&omega;}}^2(\cos \mathrm{\&theta;}+e\sin \mathrm{\&theta;}/L+\mathrm{<figure-callout\; id="2"\; label="R\; cos"\; filenames="A20061016455800221.png,A20061016455800222.png"\; state="\{\{state\}\}">R</figure-callout>}\cos 2\mathrm{\&theta;}/L)\&CenterDot;\cos \{\frac{\mathrm{\&pi;}}{2}-(\mathrm{\&phi;}+\mathrm{\&theta;})\}/\cos \mathrm{\&phi;}...\left(1\right)$

Fig. 6 (a) is the figure that the single cylinder inertia torque TI1 that calculates according to formula (1) is used curve representation as the function of crankshaft angles θ.The phase place of single cylinder inertia torque TI1 is passed the synthetic inertia torque TI that the part addition of 6 cylinders obtains shown in Fig. 6 (b) like that every 120 degree skews, can be similar to following formula (2).

TI＝-Asin3θ (2)

Wherein, A is square coefficient that is directly proportional with angular velocity of rotation ω [rad/s].

On the other hand, the moment of inertia of establishing the rotary component of crankshaft pulley, torque-converters etc. is I, and then synthetic inertia torque TI obtains (with reference to Fig. 6 (c)) by following formula (3).

TI＝I×(dω/dt) (3)

Obtain following formula (4) from formula (2) and formula (3), ω finds the solution for angular velocity of rotation, and then corresponding with synthetic torque T I inertial force rotational speed omega I is represented by following formula (5).

-Asin3θ＝I×(dω/dt) (4)

ωI＝(Acos3θ×dt/dθ)/3I (5)

Thus, θ that can wushu (5) is made as " 0 ", and passing through type (6) calculates the inertial force rotating speed OMGI at compression top dead center place.

OMGI＝(A/3I)(1/OMG) (6)

Coefficient A and rotating speed OMG square are directly proportional, and therefore proportionality constant are made as K, and then formula (6) can be deformed into formula (7).

OMGI＝K·OMG/3I (7)

The passing of the synthetic inertia torque TI of Fig. 6 (b) expression, the passing of the inertial force rotational speed omega I that Fig. 6 (c) expression is corresponding.Like this, in compression top dead center (θ=0,120,240, ...) the inertial force rotating speed OMGI that locates becomes maximum value, therefore by relative rotation speed OMGREF being added inertial force rotating speed OMGI (be equivalent to and from reference rotation speed, deduct inertial force rotating speed OMGI), can obtain getting rid of the correction relative rotation speed OMGREFM of the influence of inertial force rotational speed omega I.In addition, by in 1 TDC cycle (120 degree), correction relative rotation speed OMGREFM having been added up to eliminate the cyclical swing composition of the inertial force rotational speed omega I shown in Fig. 6 (c).

Fig. 7 is the flow chart that misfire determining is handled, and utilizes the CPU of ECU 20 to come synchronously to carry out this processing with the TDC pulsing.Wherein, for the time of origin of the CRK pulse that produces every crank shaft angle 6 degree at interval, be time parameters C RME (i), stored the so much data (i=0～ND-1, data volume ND are 120) of crank shaft angle 720 degree in the buffer memory in memory circuit.And the cylinder identiflication number of the fire order of setting up an office is that the data volume in during k (=1～6), 1 TDC is NTDC (being NTDC=20 in the present embodiment), then handles by carrying out 1 deuterzooid, carries out the computing of parameter i from (k-1) NTDC to (kNTDC-1).For example, when carrying out when processing last time with the corresponding computing of the 1st cylinder (k=1), parameter i gets from 0 value to (NTDC-1), and when carrying out with the corresponding computing of the 5th cylinder (k=5) when processing last time, parameter i gets the value from 4NTDC to (5NTDC-1).

In step S11,, time parameter CRME (i) is converted to rotating speed OMG (i) [rad/s] by following formula (8).

OMG(i)＝Dθ/CRME(i) (8)

Wherein, D θ is angle intervals 4 π/ND of instrumentation time parameter CRME, in the present embodiment, is π/30[rad].

In step S12,, carry out 720 degree Shelving, the rotating speed OMGR (i) after calculation of filtered is handled by following formula (9).

OMGR(i)＝OMG(i)-(OMG(ND)-OMG(0))×Dθ×i/4π

(9)

In step S13,, calculate relative rotation speed OMGREF by following formula (10).

OMGREF(i)＝OMGR(i)-OMGR((k-1)NTDC) (10)

Wherein, OMGR ((k-1) NTDC) is a reference rotation speed, is equivalent to judge rotating speed after the Shelving at compression top dead center place of object cylinder.

In step S14,, calculate inertial force rotating speed OMGI (k) by following formula (11).

OMGI(k)＝K·OMG((k-1)NTDC)/3I (11)

Preferably according to this moment automatic transmission lock-up clutch whether engage the value of change moment of inertia I.Thus, though the joint of lock-up clutch/disengaged all can judge accurately.

In step S15,, calculate and revise relative rotation speed OMGREFM (i) by following formula (12).

OMGREFM(i)＝OMGREF(i)+OMGI(k) (12)

In step S16,, calculate critical parameter MFJUD (k) as the aggregate-value of revising relative rotation speed OMGREFM by following formula (13).

$\mathrm{MFJUD}\left(k\right)=\underset{i=(k-1)\mathrm{NTDC}}{\overset{\mathrm{kNTDC}-1}{\mathrm{\&Sigma;}}}\mathrm{OMGREFM}\left(i\right)...\left(13\right)$

Whether in step S17, it is littler than " 0 " to differentiate critical parameter MFJUD (k), when its answer is when negating (NO), to be judged to be and to have carried out normal combustion, indicates that catching fire FMF (k) is set at " 0 " (step S18).On the other hand, when MFJUD (k)＜0, be judged to be at the #k cylinder and taken place to catch fire, sign FMF (k) is set at " 1 " (step S19) catching fire.

In step S20, judge whether cylinder identiflication number k equals cylinder number N, when its answer is when negating (NO), cylinder identiflication number k to be added " 1 " (step S22).In addition, when k=N, make cylinder identiflication number k return " 1 " (step S21).

By the processing of Fig. 7, each cylinder is carried out misfire determining.

Fig. 8 is illustrated in the various engine operating status, the emergence pattern that catches fire is changed and the result's of computational discrimination parameter MFJUD figure.Fig. 8 (a) is illustrated in the calculated data that carries out the example of normal combustion under the slow-speed of revolution low load operational state; Fig. 8 (b) is illustrated in the calculated data that carries out the example of normal combustion under the slow-speed of revolution high loaded process state.In whole cylinders, obtain on the occasion of.

Fig. 8 (c) is illustrated in the example that catches fire has taken place in No. 1 cylinder under the slow-speed of revolution low load operational state; Fig. 8 (d) is illustrated under the slow-speed of revolution low load operational state example that has taken place to catch fire in No. 1 cylinder and No. 5 cylinders; Fig. 8 (e) is illustrated under the slow-speed of revolution sub load operating condition example that has taken place to catch fire in No. 5 cylinders and No. 6 cylinders.The value that all is the critical parameter MFJUD corresponding with the cylinder that catches fire in these examples becomes negative value, can judge reliably and catch fire.

Fig. 8 (f) is illustrated under the high rotating speed low load operational state example that has taken place to catch fire in No. 1 cylinder and No. 5 cylinders; Fig. 8 (g) is illustrated in the example that catches fire has taken place in No. 5 cylinders under the high rotating speed running at full capacity state; Fig. 8 (h) is illustrated under the high rotating speed sub load operating condition example that has taken place to catch fire in No. 3 cylinders and No. 4 cylinders.Fig. 8 (i) is illustrated in the example that catches fire has taken place in No. 5 cylinders under the high rotating speed low load operational state; Fig. 8 (j) is illustrated under the intermediate speed sub load operating condition example that has taken place to catch fire in No. 1 cylinder, No. 3 cylinders and No. 4 cylinders.The value that all is the critical parameter MFJUD corresponding with the cylinder that catches fire in these examples becomes negative value, can judge reliably and catch fire.

According to above present embodiment, by being that the relative rotation speed of reference rotation speed carries out 1 accumulative total during the TDC to rotating speed with the compression top dead center place of each cylinder, calculate the critical parameter MFJUD that expression is in the generation moment of torsion of the cylinder in the combustion stroke, MFJUD carries out misfire determining according to this critical parameter.And, in the calculating of this critical parameter MFJUD, need not to carry out a plurality of Shelving corresponding with the pattern of catching fire that should detect.Therefore, can come with fairly simple computing each cylinder is carried out misfire determining accurately.

More particularly, as misfire determining object cylinder compression top dead center near detected reference rotation speed OMGR ((k-1) NTDC) and the deviation between the rotating speed OMGR that crank shaft angle 6 degree calculates, calculate relative rotation speed OMGREF, by it being added inertial force rotating speed OMGI, calculate and revise relative rotation speed OMGREFM.By adding inertial force rotating speed OMGI, the deviation of the reference rotation speed OMGR ((k-1) NTDC) that causes because of the inertial force rotating speed is proofreaied and correct, can get rid of the influence of inertial force rotating speed and carry out misfire determining accurately.

Here, the data computation that can determine clearly according to the design by the size of parts and quality etc. the inertial force rotating speed OMGI that is caused by inertial force, therefore can significantly reduce the required man-hours such as setting of decision threshold.

And, by rotating speed OMG being implemented 720 degree Shelving, calculate rotating speed OMGR after the Shelving, use Shelving after rotating speed OMGR calculate relative rotation speed OMGREF, revise relative rotation speed OMGREFM and critical parameter MFJUD.By 720 degree Shelving, can get rid of the moment of torsion that applies from the load side of motor 1, for example by the wheel of the vehicle that drives by motor 1 or the moment of torsion that subsidiary engine applies, perhaps the caused rotating speed variance components of moment of torsion that produces owing to the friction of the slide member of motor 1 is judged accurately.

In the present embodiment, crank angle position sensor 12 and ECU 20 constitute the rotary speed parameter detection unit, and ECU 20 constitutes reference value computing unit, relative velocity parameter calculation unit, identifying unit, inertial force speed composition computing unit and load torque amending unit.More particularly, the step S11 of Fig. 7 is equivalent to the part of rotary speed parameter detection unit, step S13 is equivalent to reference value computing unit and relative rotation speed parameter calculation unit, step S15～S19 is equivalent to identifying unit, step S14 is equivalent to inertial force speed composition computing unit, and step S12 is equivalent to the load torque correcting unit.

[variation]

Fig. 9 represents the variation of flow chart shown in Figure 7.Processing shown in Figure 9 is that the step S16 of processing shown in Figure 7 and S17 are changed to processing behind step S16a, S16b and the S17a.

In step S16a, by following formula (13a), as the aggregate-value of relative rotation speed OMGREF (i) and calculate critical parameter MFJUDa (k).

$\mathrm{MFJUDa}\left(k\right)=\underset{i=(k-1)\mathrm{NTDC}}{\overset{\mathrm{kNTDC}-1}{\mathrm{\&Sigma;}}}\mathrm{OMGREF}\left(i\right)...\left(13a\right)$

In step S16b, by following formula (14), computational discrimination threshold value MFTH (k).

MFTH(k)＝-NTDC×OMGI(k) (14)

Whether in step S17a, it is littler than decision threshold MFTH (k) to differentiate critical parameter MFJUDa (k), when its answer is when negating (NO), to be judged to be normal combustion and to enter step S18.On the other hand, when MFJUDa (k)＜MFTH (k), be judged to be at the #k cylinder and taken place to catch fire, and enter step S19.

In this variation, decision threshold MFTH (k) is equivalent to the aggregate-value of inertial force rotating speed OMGI.Promptly, replacement adds up revising relative rotation speed OMGREFM, by relative rotation speed OMGREF is added up, comes computational discrimination parameter MFJUDa (k), by the aggregate-value of inertial force rotating speed OMGI as decision threshold MFTH (k), can carry out the judgement identical with above-mentioned mode of execution.

In this variation, the step S16a of Fig. 9, S16b, S17a, S18 and S19 are equivalent to identifying unit.

[the 2nd mode of execution]

In the above-described embodiment, time parameter CRME is converted to rotating speed OMG, use rotating speed OMG to carry out misfire determining, but in the present embodiment, service time, parameters C RME carried out misfire determining as parameter of velocity as parameter of velocity.And, except that the point that the following describes, all identical with the 1st mode of execution.

Figure 10 is the flow chart that time parameter CRME is used as the misfire determining processing of parameter of velocity.

In step S32, by following formula (21), carry out 720 degree Shelving, calculation of filtered is handled back time parameter CRMER (i).

CRMER(i)＝CRME(i)

-(CRME(0)-CRME(ND))×Dθ×i/4π

(21)

In step S33,, calculate relative time parameters C RMEREF (i) by following formula (22).

CRMEREF(i)＝CRMER((k-1)NTDC)-CRMER(i) (22)

Wherein, CRMER ((k-1) NTDC) is parameter fiducial time, is equivalent to judge time parameter after the Shelving at compression top dead center place of cylinder of object.

In step S34,, calculate inertial force time parameter CRMEI (k) by following formula (23).

CRMEI(k)＝3I·CRME((k-1)NTDC)/K (23)

In step S35,, calculate and revise relative time parameters C RMEREFM (i) by following formula (24).

CRMEREFM(i)＝CRMEREF(i)-CRMEI(k) (24)

In step S36, by following formula (25), computational discrimination parameter MFJUDb (k) is as the aggregate-value of revising relative time parameters C RMEREFM.

$\mathrm{MFJUDb}\left(k\right)=\underset{i=(k-1)\mathrm{NTDC}}{\overset{\mathrm{kNTDC}-1}{\mathrm{\&Sigma;}}}\mathrm{CRMEREFM}\left(i\right)...\left(25\right)$

Whether in step S37, it is littler than " 0 " to differentiate critical parameter MFJUDb (k), when its answer is when negating (NO), to be judged to be and to have carried out normal combustion, indicates that catching fire FMF (k) is set at " 0 " (step S38).On the other hand, when MFJUDb (k)＜0, be judged to be at the #k cylinder and taken place to catch fire, sign FMF (k) is set at " 1 " (step S39) catching fire.

In step S40, judge whether cylinder identiflication number k equals cylinder number N, when its answer is when negating (NO), cylinder identiflication number k to be added " 1 " (step S42).In addition, when k=N, make cylinder identiflication number k return " 1 " (step S41).

As reference Fig. 2 (b) illustrates, the aggregate-value of relative time parameters C RMEREF depends on having or not of catching fire, similarly change with the aggregate-value of relative rotation speed OMGREF, therefore can similarly carry out misfire determining exactly with the 1st mode of execution to each cylinder.

In the present embodiment, the step S33 of Figure 10 is equivalent to reference value computing unit and relative velocity parameter calculation unit, step S36～S39 is equivalent to identifying unit, and step S34 and S35 are equivalent to inertial force speed composition computing unit, and step S32 is equivalent to the load torque correcting unit.

[variation]

Figure 11 represents the variation of flow chart shown in Figure 10.Processing after the processing shown in Figure 11 is that the step S36 of processing shown in Figure 10 and S37 are changed to step S36a, S36b and S37a.

In step S36a, by following formula (25a), as the aggregate-value of relative time parameters C RMEREF (i) and calculate critical parameter MFJUDc (k).

$\mathrm{MFJUDc}\left(k\right)=\underset{i=(k-1)\mathrm{NTDC}}{\overset{\mathrm{kNTDC}-1}{\mathrm{\&Sigma;}}}\mathrm{CRMEREF}\left(i\right)...\left(25a\right)$

In step S36b, by following formula (26), computational discrimination threshold value MFTHa (k).

MFTHa(k)＝NTDC×CRMEI(k) (26)

Whether in step S37a, it is littler than decision threshold MFTHa (k) to differentiate critical parameter MFJUDc (k), when its answer is when negating (NO), to be judged to be normal combustion and to enter step S38.On the other hand, when MFJUDc (k)＜MFTHa (k), be judged to be at the #k cylinder and taken place to catch fire, and enter step S39.

In this variation, decision threshold MFTHa (k) is equivalent to the aggregate-value of inertial force time parameter CRMEI.Promptly, replacement adds up revising relative time parameters C RMEREFM, by relative time parameters C RMEREF is added up, come computational discrimination parameter MFJUDc (k), by the aggregate-value of inertial force time parameter CRMEI as decision threshold MFTHa (k), can carry out and the identical judgement of above-mentioned the 2nd mode of execution.

In this variation, the step S36a of Figure 11, S36b, S37a, S38 and S39 are equivalent to identifying unit.

[other variation]

The present invention is not limited to above-mentioned mode of execution, can carry out various distortion.For example, in the above-described embodiment, time parameter CRME (i) is applied to formula (8), calculates rotating speed OMG, but in order not reduce calculation accuracy when the high rotating speed, the preferred aggregate-value CRME30 (i) of 5 time parameter CRME by following formula (31) calculating that uses calculates rotating speed OMG.

$\mathrm{CRME}30\left(i\right)=\underset{j=0}{\overset{4}{\mathrm{\&Sigma;}}}\mathrm{CRME}(i+j)...\left(31\right)$

In this case, rotating speed OMG (i) calculates by following formula (8a).But,, therefore carry out respective phase and proofread and correct because the calculating phase place of rotating speed has skew.

OMG(i)＝5Dθ/CRME30(i) (8a)

And, in the above-described embodiment, for reference rotation speed (parameter fiducial time) as the calculating benchmark of relative rotation speed OMGREF (relative time parameters C RMEREF), used the rotating speed (time parameter) at the compression top dead center place of each cylinder, but sampling timing need not consistent exactly with compression top dead center, as long as near compression top dead center (for example ± 7.5 in Du the scope).At this, 7.5 degree and the sampling period of rotary speed parameter are that the situations of 15 degree are corresponding, usually, are θ SPL if establish the sampling period, then can use the rotary speed parameter of sampling in the scope of ± θ SPL/2.

And 720 degree Shelving can replace the processing of above-mentioned formula (9) and be undertaken by following formula (9a).Following formula (9a) be to use crank shaft angle 720 degree during the moving average OMGAVE (m) of rotating speed OMG eliminate the processing of linear change composition.Wherein, m is the discretization moment corresponding with the cycle of crank shaft angle 720 degree.

OMGR(i)＝OMG(i)

-(OMGAVE(m)-OMGAVE(m-1))×Dθ×i/4π

(9a)

[the 3rd mode of execution]

Present embodiment changes the computational methods of the correction relative rotation speed OMGREFM of first mode of execution, to get rid of the influence of reversing the interference that the detection error with the time parameter CRME of crank angle position sensor causes because of bent axle.

The example of the measured data of relative rotation speed OMGREFM is revised in Figure 12 (a) expression, and the part that impales of with dashed lines is the part that is subjected to above-mentioned interference effect in the figure.When having the influencing of such interference, the possibility that produces the misinterpretation that catches fire uprises.Therefore, in the present embodiment, by multiply by burning correlation function FCR to revising relative rotation speed OMDREFM, get rid of the influence of above-mentioned interference, this burning correlation function FCR is the function to carrying out normal combustion and not existing checkout value to crank angle position sensor to bring the rotation speed change under the situation of interference of influence to be similar to.Figure 12 (b) expression has improved the waveform that the with dashed lines shown in Figure 12 (a) impales part by the correction relative rotation speed OMGREFM shown in Figure 12 (a) being multiply by the correction relative rotation speed OMGREFMb that burning correlation function FCR calculates.

Use the function shown in Figure 13, promptly by the function of following formula (41) definition as burning correlation function FCR.Wherein, N is that cylinder number, θ are that the angle that piston with specific cylinder is positioned at upper dead center is the crank shaft angle (with reference to Fig. 5) of benchmark.In addition, Figure 13 represents the corresponding burning correlation function of the 6 Cylinder engines FCR with present embodiment.

FCR＝{1-2cos(N·θ/2)}/2 (41)

In addition, also for example in the steady running state behind the warming-up of motor, the in-cylinder pressure of each cylinder during the instrumentation normal combustion, carry out addition by in-cylinder pressure to each cylinder of measuring, calculating synthetic in-cylinder pressure changes, be scaled change in rotational speed by synthesizing the in-cylinder pressure variation, obtained burning correlation function FCR.Figure 14 is the figure that represents the burning correlation function FCR that obtains like this.Burning correlation function shown in Figure 14 is the rotation speed change waveform under the normal combustion state to be normalized into minimum value be " 0 " and the maximum value function for " 1 ".

The example by the deviation range (mean value (bullet) ± 3 σ) of the critical parameter MFJUD of the relative rotation speed timing of burning correlation function realization is not carried out in Figure 15 (a) expression, the example of the deviation range of the critical parameter MFJUDd of Figure 15 (b) expression present embodiment.Can understand from these figure,, can improve the calculation accuracy of critical parameter MFJUDd, reduce deviation range (in illustrative example, reducing 40% approximately) by having used the correction of burning correlation function FCR.Its result can improve the precision of misfire determining.

Figure 16 is the flow chart that the misfire determining of present embodiment is handled.Step S51～S53 is identical with step S11～S13 of Fig. 7, and step S59～S63 is identical with step S18～S22 of Fig. 7.

In step S54, in following formula (42), use the inertial force rotating speed OMGI (k) that passing through type (11) calculates, calculate inertial force rotating speed OMGIa (i).In the 1st mode of execution, the inertial force rotating speed OMGI (k) at compression top dead center place is directly applied to formula (12), calculate and revise relative rotation speed OMGREFM (i), but in the present embodiment, calculate the inertial force rotating speed OMGIa (i) of each sampling timing, carry out the correction of relative rotation speed OMGREF.In formula (42), the reason of the inertial force rotating speed OMGI (k-3) before using during 3 TDC is, uses the operational precision height of intermediate value in 720 above-mentioned degree Shelving.In addition, parameter k is the cylinder identiflication number, and k=0 ,-1 ,-2 is corresponding with k=N (=6), N-1 (=5), N-2 (=4) respectively.

OMGIa(i)＝OMGI(k-3)×{cos(N·Dθ·i/2)-1}

(42)

In step S55, use the inertial force rotating speed OMGIa (i) that in step S54, calculates by following formula (43), calculate the 1st and revise relative rotation speed OMGREFMa (i).

OMGREFMa(i)＝OMGREF(i)-OMGIa(i) (43)

In step S56, in following formula (45), be applied in the 1st correction relative rotation speed OMGREFMa (i) that calculates among the step S55, and, calculate the 2nd and revise relative rotation speed OMGREFMb (i) by the burning correlation function FCR (i) that following formula (44) calculates.Formula (44) is the formula that the θ of formula (41) is replaced into (D θ i).

FCR(i)＝{1-2cos(N·Dθ·i/2)}/2 (44)

OMGREFMb(i)＝OMGREFMa(i)×FCR(i) (45)

In step S57, by following formula (46) computational discrimination parameter MFJUDd (k).

$\mathrm{MFJUDd}\left(k\right)=\underset{i=(k-1)\mathrm{NTDC}}{\overset{\mathrm{kNTDC}-1}{\mathrm{\&Sigma;}}}\mathrm{OMGREFMb}\left(i\right)...\left(46\right)$

In step S58, differentiate whether critical parameter MFJUDd (k) is negative value, answering when this is when affirming ("Yes"), to be judged to be and to have taken place to catch fire, and enters step S60.On the other hand, when MFJUDd (k) 〉=0, enter step S59.

Below so in the present embodiment, by from relative rotation speed OMGREF (i), deducting inertial force rotating speed OMGIa (i), calculate the 1st and revise relative rotation speed OMGREFMa, and then by the 1st correction relative rotation speed OMGREFMa be multiply by burning correlation function FCR, calculate the 2nd and revise relative rotation speed OMGREFMb, carry out integration by revising relative rotation speed OMGREFMb to the 2nd, come computational discrimination parameter MFJUDd, therefore, can get rid of the influence that the checkout value of crank angle position sensor 12 is brought the interference of influence, improve the precision of misfire determining.

By the burning correlation function FCR (i) shown in the use formula (44), need not to be used to set the experiment that the burning correlation function value calculates the table of usefulness, can carry out suitable correction by fairly simple computing, and irrelevant with number of cylinders.

In the present embodiment, the step S51 of Figure 16 is equivalent to the part of rotary speed parameter detection unit, step S53 is equivalent to reference value computing unit and relative velocity parameter calculation unit, step S55～S60 is equivalent to identifying unit, step S54 is equivalent to inertial force speed composition computing unit, and step S52 is equivalent to the load torque correcting unit.

[variation]

Under the situation of use based on the burning correlation function of the measured data shown in Figure 14, in storage, store the FCR table of retrieving the functional value FCR (i) in 1 cycle shown in Figure 14 according to parameter i in advance, in step S56, substitute computing based on formula (44), carry out the FCR table search.By using burning correlation function based on measured data, can in the burning correlation function, reflect the characteristic of internal-combustion engine, can carry out more suitable correction.

In addition, the computing of formula (44) also can be retrieved this table of natural cosines and be calculated burning correlation function value FCR (i) by storing cosine function as table in advance in storage.

In addition, the inertial force rotating speed OMGI (k-3) of formula (42) is also replaceable for working as previous value OMGI (k).

In addition, use the correction of burning correlation function FCR also applicable to described second mode of execution.

And, in the above-described embodiment, show 6 cylinder engines used example of the present invention, no matter but how much all applicable the present invention's number of cylinders is.And the present invention is also applicable at the petrol engine of firing chamber inner direct fuel or the misfire determining of diesel engine.And the present invention is also applicable to the misfire determining with motor etc. such as the Ship Propeling of machine outside that bent axle is made as Vertical direction etc.

Claims (8)

1. the misfire detecting apparatus of an internal-combustion engine, the misfire detecting apparatus of this internal-combustion engine has the rotary speed parameter detection unit that detects the rotary speed parameter corresponding with the rotating speed of internal-combustion engine, detect catching fire of described internal-combustion engine according to detected rotary speed parameter, it is characterized in that the misfire detecting apparatus of this internal-combustion engine has:

The reference value computing unit, it calculates the reference value of described rotary speed parameter;

The relative velocity parameter calculation unit, it calculates described reference value and the deviation between the detected rotary speed parameter of regulation crank shaft angle as the relative velocity parameter; And

Identifying unit, it calculates the aggregate-value of described relative velocity parameter, carries out misfire determining according to the aggregate-value of this calculating.

2. the misfire detecting apparatus of internal-combustion engine according to claim 1 is characterized in that, described reference value is near the piston that becomes the cylinder of a misfire determining object detected described rotary speed parameter when being positioned at the compression top dead center.

3. the misfire detecting apparatus of internal-combustion engine according to claim 1 and 2 is characterized in that, described identifying unit adds up described relative velocity parameter in during crank shaft angle 720/N degree, and wherein, N is the cylinder number of described internal-combustion engine.

4. the misfire detecting apparatus of internal-combustion engine according to claim 1, it is characterized in that, the misfire detecting apparatus of this internal-combustion engine also has inertial force speed composition computing unit, it calculates the inertial force rotating speed composition that the inertial force by the movable member of described internal-combustion engine causes, described identifying unit becomes to assign to carry out described misfire determining according to described relative velocity parameter and inertial force rotating speed.

5. the misfire detecting apparatus of internal-combustion engine according to claim 1, it is characterized in that, the misfire detecting apparatus of this internal-combustion engine also has inertial force speed composition computing unit, it calculates the inertial force rotating speed composition that the inertial force by the movable member of described internal-combustion engine causes, described identifying unit becomes to assign to revise described relative velocity parameter with described inertial force rotating speed, thereby calculate the 1st and revise the relative velocity parameter, the burning correlation function that rotation speed change when revising the relative velocity parameter and multiply by normal combustion the 1st is similar to, calculate the 2nd and revise the relative velocity parameter, carry out described misfire determining according to the 2nd integral value of revising the relative velocity parameter.

6. the misfire detecting apparatus of internal-combustion engine according to claim 5 is characterized in that, described burning correlation function is defined by following formula:

(1-2cos(N·θ/2))/2

Wherein, N is the cylinder number of described internal-combustion engine, and θ is that the angle that the piston with the specific cylinder of described internal-combustion engine is positioned at upper dead center position is the crank shaft angle of benchmark.

7. the misfire detecting apparatus of internal-combustion engine according to claim 5 is characterized in that, described burning correlation function is the rotation speed change waveform under the normal combustion state of described internal-combustion engine to be normalized into minimum value be " 0 " and the maximum value function for " 1 ".

8. the misfire detecting apparatus of internal-combustion engine according to claim 1, it is characterized in that, the misfire detecting apparatus of this internal-combustion engine also has the load torque correcting unit, it is proofreaied and correct described rotary speed parameter, the rotating speed variance components that the moment of torsion that applies to described internal-combustion engine because of the load side from described internal-combustion engine with eliminating causes, rotary speed parameter after described reference value computing unit and the utilization of relative velocity parameter calculation unit are proofreaied and correct by described load torque correcting unit carries out the calculating and the described relative velocity CALCULATION OF PARAMETERS of described reference value respectively.

Images