CN101509433A - Oxygen sensor deterioration emulator control deviation calibrating method based on lambda closed-loop control - Google Patents

Abstract

The invention discloses a calibrating method of control deviation of a deterioration simulator of a Lambda control-based oxygen sensor, comprising the following steps: measuring the value of Lambda closed-loop control cycle in different deterioration simulation delay time and then comparing the measured value with the theoretical calculating value of the Lambda closed-loop control cycle in different deterioration simulation delay time to obtain the difference value of the measured value and the theoretical calculating value, and then calculating the control deviation of the deterioration simulator of the oxygen sensor on the deterioration simulation delay time according to the difference value and calibrating the deterioration simulator of the oxygen sensor in accordance with the control deviation. The calibrating method can avoid the difference of test results caused by control deviation of different simulators, which is convenient and fast.

Description

Calibration steps based on the oxygen sensor deterioration emulator control deviation of Lambda closed loop control

Technical field

The present invention relates to automobile electronic fuel oil jet OBD (in-circuit diagnostic system) system, particularly relate to a kind of calibration steps of the oxygen sensor deterioration emulator control deviation based on Lambda (excess air coefficient is equally represented the concentration of mixed gas with air fuel ratio) control.

Background technique

The deterioration of the vitals lambda sensor of the necessary Monitoring and Controlling discharging of OBD laws and regulations requirement automobile electronic fuel oil jet OBD system.Intensification along with the oxygen sensor deterioration degree, the discharging of vehicle will more and more worsen, and OBD laws and regulations requirement automobile electronic fuel oil jet OBD system must be able to cause vehicular discharge to quote the fault of oxygen sensor deterioration before surpassing OBD rules limit value in the oxygen sensor deterioration degree.For this reason, in the calibration process of oxygen sensor deterioration monitoring function, and car load factory all needs to simulate with oxygen sensor deterioration emulator the degradation failure of lambda sensor to the organs of state power's demonstration oxygen sensor deterioration monitoring function time.The working principle of oxygen sensor deterioration emulator is to import ECU again after oxygen sensor signal is postponed the regular hour, has represented the deterioration of lambda sensor in various degree different retard time.Yet different simulators are owing to exist the difference of control deviation, can exist under the situation of setting identical retard time, because the actual delay temporal differences causes match test or Demonstrator Trials result's difference, can cause Demonstrator Trials failure (do not report fault or discharging is transfinited) when serious.Therefore, be necessary the oxygen sensor deterioration emulator control deviation is calibrated.

And the enterprise (electric injection system supplier and car load factory) that oxygen sensor deterioration emulator is used in current domestic demands does not have control substantially to the simulator control deviation, comprise the oxygen sensor deterioration emulator of buying from German ETAS company, also control deviation is not marked.If desired the simulator control deviation is proofreaded, general way is the time difference with the oxygen sensor signal saltus step of oscillograph monitoring input and output.Therefore, need the oscillograph equipment of specialty and the special expertise that the test engineer uses this equipment.Because what test obtained is analogue signal, the acquisition process of the processing of test data and final test result is more loaded down with trivial details, and in addition, accidentalia and personal factor are bigger to the test result influence.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of calibration steps of the oxygen sensor deterioration emulator control deviation based on Lambda control, can avoid the difference of the test result that caused by different simulator control deviations, and convenient and swift.

For solving the problems of the technologies described above, the calibration steps of the oxygen sensor deterioration emulator control deviation based on Lambda control of the present invention is: measure the value of Lambda closed loop control cycle under the different deterioration analogue delay times, and resultant measured value compared with the calculated value of Lambda closed loop control cycle under the different deterioration analogue delay times respectively, obtain the difference of measured value and calculated value, and calculate the control deviation of oxygen sensor deterioration emulator according to this difference, according to this control deviation described oxygen sensor deterioration emulator is calibrated.

Described control deviation is a proportional jitter.Relevant test result shows, oxygen sensor deterioration emulator forms the error accumulation of the control deviation cause internal counter of deterioration analogue delay time, thereby it is proportional with the deterioration analogue delay time, after obtaining this proportional jitter by this method, for this simulator, after the deterioration analogue delay time of setting carried out this ratio correction, just can obtain the deterioration analogue delay time of reality.

The present invention is based on a kind of that the research of Lambda closed loop control (PI control) relevant feature parameters (dead time, control cycle, Lambda target deviation etc.) is obtained the oxygen sensor deterioration emulator control deviation is realized the rapid and convenient Calibration Method.Adopt method of the present invention, as long as any one calibration engineer carries out the measurement of the Lambda closed loop control of one group of different oxygen sensor deterioration emulator deterioration analogue delay under the time, read in the software of exploitation for it with measuring file, just can obtain this oxygen sensor deterioration emulator quickly and easily to the control deviation of deterioration analogue delay time, thereby guarantee the conformity of the oxygen sensor deterioration test result of on different oxygen sensor deterioration emulators, carrying out.

Description of drawings

The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment:

Fig. 1 is the oxygen sensor deterioration emulator control deviation calibration software surface chart that the present invention adopts;

Fig. 2 is that regulated quantity fr changes schematic representation in the Lambda closed loop control process;

Fig. 3 is a regulated quantity fr situation of change schematic representation under the limit case (I=0, P=2 Δ L);

Fig. 4 is a regulated quantity fr situation of change schematic representation under the limit case (P=0);

Fig. 5 is a regulated quantity fr situation of change schematic representation under the lambda sensor cycle deterioration condition;

Fig. 6 is the situation schematic representation of Lambda closed loop control regulated quantity fr when reaching limit value;

Fig. 7 is the lambda sensor performance diagram;

Fig. 8 is the comparison diagram of Lambda control cycle measured value and calculated value under the situation of different lambda sensor cycle deterioration analogue delays in the demonstration test;

Fig. 9 is the proportional jitter figure of the control following retard time of retard time that different oxygen sensor deterioration emulators are set in the demonstration test;

Figure 10 is the calculated value in revised Lambda closed loop control cycle in the demonstration test and the comparison diagram of measured value;

Figure 11 is the calibration steps control flow chart of the oxygen sensor deterioration emulator control deviation based on Lambda control of the present invention;

Figure 12 is a method software control schematic flow sheet of the present invention.

Embodiment

Adopt method of the present invention to read in the software of exploitation for it with measuring file.The interface of this software as shown in Figure 1.Upper left of this software interface order button " ... " be used to select the measurement file of calibration test, in the filename of measurement file and the static text frame that the path will be presented at the left side.The order button on the right " is read to measure file " and is used to read the data of measuring file, comprises rotating speed and the information on load of measuring operating point, will be presented in the engine speed and two static text frames of engine load in " measuring operating point information " hurdle.The regulated quantity fr of Lambda closed loop control and closed loop control cycle tpotv will be presented among the axle figure of bottom, interface.The Lambda Control Parameter " please be imported " in a left side hurdle, P (ratio) part of Lambda closed loop control when needing the input calibration test and the setting of I (integration) part and the upper and lower of Lambda closed loop control regulated quantity fr, be used to calculate the theoretical control cycle of the Lambda closed loop under each deterioration analogue delay time situation, and Lambda closed loop control regulated quantity fr is reached the estimation that abnormal conditions appear in Lambda closed loop control computation of Period value after the upper and lower.Two axle figure on the right, following one has reflected the difference between the Lambda closed loop control computation of Period value and measured value under the corresponding different deterioration analogue delay time; One of top has been reflected according to the difference between Lambda closed loop control cyclical theory calculated value and the measured value, the proportional jitter of each the measuring point deterioration analogue delay time control that calculates, for existing the Lambda regulated quantity to reach the measuring point of limit value, will identify with red circle.The calibration test result that upper right static text frame " this lambda sensor simulator control deviation is: " expression is final, as shown in FIG.: the deterioration analogue delay time that the actual deterioration analogue delay time ratio of+10% representative is set is big by 10%, promptly on this oxygen sensor deterioration emulator, if be 400ms the retard time of setting, then should be 440ms Shi Ji retard time.

The present invention is by the relation between each characteristic parameter of research Lambda closed loop control, the computational methods in Lambda closed loop control cycle have been obtained, analyze the source of error of these computational methods, be divided into random error (comprising the unstability of pre-control air fuel ratio and the randomness of lambda sensor characteristic) and system deviation (oxygen sensor deterioration emulator is to the control deviation of deterioration analogue delay time).By a plurality of Lambda closed loop control cycles are averaged eliminate at random erroneous judgement after, remaining deviation is exactly the control deviation of oxygen sensor deterioration emulator.Therefore, can obtain oxygen sensor deterioration emulator to the control deviation of deterioration analogue delay time by measuring measured value and the difference of calculated value of oxygen sensor deterioration emulator under the different deterioration analogue delay times, and then this control deviation is proofreaied and correct.

Theoretical analysis in detail and reasoning process are as follows.

Because the existence in Lambda closed loop control (PI control) dead time, automobile electronic fuel oil jet system could be by the perception of lambda sensor institute after need passing through this dead time by the change oil spout to the adjustment of air fuel ratio.For the two point form lambda sensor, near because lambda sensor characteristic (there is saltus step in output voltage Lambda equals 1.0), top description can become: when the Lambda closed loop control adjusts to 1.0 with the Lambda of system, need just have the saltus step of oxygen sensor voltage through after this dead time.Carrying out P when electric injection system detects the oxygen sensor voltage saltus step earlier partly regulates and (does not temporarily consider the tv part, notes: tv partly is by prolonging Lambda regulating and controlling amount fr in the means of the waiting time of dense side or rare side to realize the adjustment of Lambda window is discharged with reduction), then carry out I and partly regulate, detect voltage jump next time up to lambda sensor.

The variation of regulated quantity fr is referring to shown in Figure 2 in the Lambda closed loop control process.It is 1.0 (fr differs and is decided to be 1.0) that center line has wherein been represented Lambda, t _dRepresent the dead time of Lambda closed loop control, t _pRepresent the Lambda closed loop control cycle; Earlier temporarily do not consider the tv part, therefore, the t here _pSay on the stricti jurise and represent tpotv.And Δ L represents the regulation range of Lambda closed loop control, although the Δ L in Fig. 2 represents the scope of Lambda control to the oil spout correction, owing to the corresponding relation of oil spout correction and Lambda, in fact represented the result of Lambda closed loop control: the excursion of Lambda.P represents the P (ratio) of Lambda closed loop control, and partly (in the BOSCH system is in the Bosch system, corresponding parameter: KFRP).Also use I (integration) in following derivation, I represents I (integration) part of Lambda control, (in the BOSCH system, corresponding parameter: KFRI).

Relation between above-mentioned each variable can be summed up as following relation:

$P+\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}*I=2\mathrm{\&Delta;L}$

... ... ... (formula 1)

$\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}\&GreaterEqual;t_d$

P in two kinds of situation below〉Δ L and P≤Δ L further discuss the relation between each parameter.

(1)P>ΔL

As P〉mean during Δ L: when lambda sensor detected mixed gas dense (or rare), rare (or dense) side was directly regulated back air fuel ratio in the adjusting meeting of P part; Then when reaching lambda sensor after the process dead time, this part mixed gas will inevitably cause the saltus step of oxygen sensor voltage, so have all the time:

$\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}=t_d$ ... ... ... ... .. (formula 2)

So have:

P+I*t _d=2 Δ L......................... (formula 3)

As can be seen from the above equation, as long as P partly is not more than 2 Δ L, electric injection system still can be controlled at Lambda ± Δ L in; As long as the I part is enough little, limit case is: I=0, and P=2 Δ L, at this moment, in the ideal case, Lambda should present the form of a square wave, and the cycle is 2t _d, as shown in Figure 3.When P part during greater than 2 Δ L, electric injection system can not be controlled at Lambda ± Δ L in.

(2)P≤ΔL

The situation of P≤Δ L is the corresponding situation of seeing usually (the Lambda closed loop control after overmatching is all to planting situation), and in this case, Lambda passes through moment of 1.0 and occurs in the process that I partly regulates, as shown in Figure 1, so have:

I*t _d=Δ L.............................. (formula 4)

Can obtain by formula 1:

$\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}=\frac{2\mathrm{\&Delta;L}-P}{I}=t_d+\frac{\mathrm{\&Delta;L}-P}{I}$ ... ... .. (formula 5)

The implication of formula 5 representative is: when the adjusting of P part during less than Δ L, promptly when lambda sensor detected mixed gas and is dense (or rare), the adjusting of P part can not be regulated back air fuel ratio rare (or dense) side, then the half period controlled of Lambda

Will be than dead time t _dLong, the part of growth is deficiency (for the P part of Lambda being adjusted to 1.0 is big or small) the required time that I partly remedies the P part.So the P part is more little, respective cycle can be long more.Be under 0 the situation, to have at limit case P:

$\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}=\frac{2\mathrm{\&Delta;L}}{I}={2t}_d$ ... ... ... ... (formula 6)

This moment Lambda closed loop control cycle t _pIrrelevant with the size of I part, be dead time t _d4 times, referring to shown in Figure 4.

This also is why can partly be that 0 o'clock Lambda closed loop control cycle tp obtains the dead time t that Lambda controls by measuring P _dThereby carry out the reason of the relevant parameter coupling of Lambda closed loop control.

Further transformation for mula 5 can obtain:

$\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}=\frac{2\mathrm{\&Delta;L}-P}{I}={2t}_d-\frac{P}{I}$ ... ... ... (formula 7)

Following formula shows, under the condition that satisfies P≤Δ L, as long as known the dead time t of Lambda closed loop control _d, the Lambda closed loop control cycle under any P part and the I part combined situation can calculate according to formula 7.

Referring to shown in Figure 5, with regard to the dead time t of Lambda closed loop control _dPhysical significance, should comprise that burning, the waste gas after burning of mixed gas in cylinder after the oil spout flow to the time of lambda sensor and the reaction time of lambda sensor from exhaust valve, therefore for the situation of lambda sensor cycle deterioration, can be regarded as dead time t _dElongated (reaction time prolongation).So, new dead time t _d' should be original dead time t _dAdd the delay t of lambda sensor reaction _Delay:

$t_d\&prime;=t_d+t_{\mathrm{delay}}$ ... ... ... .... (formula 8)

Can get by formula 7:

$\frac{t_p\&prime;}{2}={2t}_d\&prime;-\frac{P}{I}$ ... ... ... .... (formula 9)

Wherein P and the I situation before with respect to deterioration does not change, so have:

$\frac{t_p\&prime;}{2}=2(t_d+t_{\mathrm{delay}})-\frac{P}{I}=({2t}_d-\frac{P}{I})+{2t}_{\mathrm{delay}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; p"\; filenames="A200810044198E00241.png,A200810044198E00253.png"\; state="\{\{state\}\}">t</figure-callout>}}_p}{2}+{2t}_{\mathrm{delay}}$ ... ... ... (formula 10)

The following formula explanation, oxygen sensor deterioration response delay t _DelayAfter the Lambda closed loop control cycle be Lambda closed loop control cycle t before the deterioration _pAdd 4 times response delay time t _Delay

Fig. 5 has also reflected the relation in the formula 10, the corresponding response delay t of dotted line _DelayAfter the Lambda closed loop control, part was 1/2 cycle after the deterioration between two P regulated, for 1/2 original cycle adds 2 response delay t _DelayTime.As can be seen from Figure 5, why the Lambda closed loop control cycle after the deterioration is to add 4 times of response delay time t on the basis in former Lambda closed loop control cycle _Delay, be because on the one hand since response delay cause system detect the dense rare saltus step of mixed gas time retardation a response delay time t _Delay, and during partly continuation effect of I, cause the regulated quantity fr of closed loop control to continue to have increased I*t _DelaySo, after system detects dense rare saltus step, also need the identical time that the regulated quantity fr of closed loop control is adjusted to original level, therefore for a dense rare saltus step, front and back have increased by 2 times of response delay time t _Delay

But should see, when above-mentioned derivation, not consider the situation when Lambda closed loop control regulated quantity fr reaches limit value.When Lambda closed loop control regulated quantity reaches limit value, regulated quantity will maintain on the limit value, detect dense rare saltus step up to system.At this moment, the adjusting of P part will be an initial point with this limit value, and the I part is adjusted to the time t that original level then no longer needs a response delay with the regulated quantity of Lambda closed loop control for this reason _Delay, mixed gas will arrive dense rare trip point in advance, as shown in Figure 6.Time in advance is identical with the time that the Lambda regulated quantity maintains on the limit value, thereby the Lambda closed loop control cycle is shortened; Therefore, formula 10 will not be suitable for.Certainly, the pre-control deviation of only very big in the time of deterioration analogue delay or the air fuel ratio of this situation very greatly and do not carry out just may occurring under the situation of self study.

More than deriving all is to be based upon air fuel ratio to control absolute stability in advance, the air fuel ratio that is pre-control is an absolute stability, absolute unanimity of the characteristic of lambda sensor and oxygen sensor deterioration emulator, there are differences with this ideal situation but actual conditions are inevitable on the time on the absolute accurate basis at control lambda sensor response delay.Above-mentioned factor is discussed is respectively below calculated the oxygen sensor deterioration influence in front and back Lambda closed loop control cycle adopting method of the present invention.

(1) unstability of pre-control air fuel ratio is to calculating the oxygen sensor deterioration influence in front and back Lambda closed loop control cycle.

The factor that influences pre-control air fuel ratio stability is a lot, mainly contains: the fuel injection quantity calculation deviation that the unstability of the unstability of engine charge, the tolerance of oil sprayer and oil spout flow is brought etc.Can imagine, system's air fuel ratio is adjusted to Lambda is near 1.0 the time when the I of Lambda closed loop control part regulated quantity increases (or reducing) gradually, if above-mentioned factor causes in advance (or postponement) to form the mixed gas of dense (rare), this part mixed gas arrives lambda sensor through the mobile back in a dead time so, will certainly shift to an earlier date the saltus step of (or postponement) oxygen sensor voltage, make to measure control cycle (or dead time) (or bigger than normal) less than normal.But the influence that should see these factors all is at random, and the result of its influence should meet the rule of normal distribution.Therefore in test, increase the influence that sampling sample (getting a plurality of control cycles averages) just can be eliminated this part factor to a great extent.

(2) enchancement factor of lambda sensor characteristic is to calculating the oxygen sensor deterioration influence in front and back Lambda closed loop control cycle.

The characteristic of lambda sensor has determined that the lambda sensor output voltage is to have saltus step near 1.0 at Lambda.Survey data in the lambda sensor characteristic curve shown in Figure 7 shows that when oxygen sensor voltage was all 0.45V, the Lambda of Ce Lianging was all different several times.Equally, if Lambda is identical, the oxygen sensor voltage that at every turn measures also can there are differences, and very big randomness is arranged.Because the existence of this specific character of lambda sensor, must cause each Lambda closed loop control Lambda to be adjusted in 1.0 the process, the oxygen sensor voltage jumping moment there are differences, and causes measuring the difference in Lambda closed loop control cycle.

But should see that equally the influence of this factor is at random, it also should meet the rule of normal distribution to result's influence.Equally in test, also can eliminate the influence of this part factor to a great extent by increasing sampling sample (getting a plurality of control cycles averages).

(3) oxygen sensor deterioration emulator to the control deviation of simulation deterioration analogue delay time to calculating the influence in Lambda closed loop control cycle before and after the oxygen sensor deterioration.

If there is deviation in oxygen sensor deterioration emulator to the control of deterioration analogue delay time, promptly there are differences the difference in Lambda closed loop control cycle after the deterioration that Lambda closed loop control cycle and actual measurement obtain after the deterioration that just must cause extrapolating the retard time of deterioration analogue delay time of She Dinging and oxygen sensor deterioration emulator practical function.But what this influence caused is systematic deviation.Because oxygen sensor deterioration emulator is to realize control to the deterioration analogue delay time by a counter, therefore have reason to make such conjecture, if being the error accumulation by its counter, the control deviation of oxygen sensor deterioration emulator forms, then the absolute deviation of its control should be directly proportional with the response delay time of its setting, therefore, the control deviation of oxygen sensor deterioration emulator should be a proportional jitter.In demonstration test subsequently, fully verified above-mentioned conjecture.

From top error analysis, can obtain, by a plurality of Lambda closed loop control cycles are averaged, after having eliminated the influence of unstability to the projectional technique in Lambda closed loop control cycle of the unstability of pre-control air fuel ratio and lambda sensor characteristic, remaining can only be the difference that control deviation caused of oxygen sensor deterioration emulator to the response delay time.Therefore, calculated value that just can be by the Lambda closed loop control cycle and the difference between the measured value are calculated oxygen sensor deterioration emulator to the control deviation of deterioration analogue delay time conversely, come in view of the above the control deviation of oxygen sensor deterioration emulator is calibrated (referring to shown in Figure 12).

The control cycle projectional technique can pass through verification experimental verification under the oxygen sensor deterioration situation recited above, and purpose is to verify the accuracy of Lambda control cycle projectional technique under the oxygen sensor deterioration situation; The result of test verifies the accuracy of said method on the one hand, also provides strong evidence for the calibration steps of the oxygen sensor deterioration emulator control deviation that obtains from the error analysis of this method on the other hand.

Test is carried out in the drum test chamber, and test vehicle is a car, and engine displacement is 1.3 liters.The oxygen sensor deterioration emulator model of using is GRS, for ETAS company produces.Test procedure is as follows:

Select the operating point (3000 rev/mins of rotating speeds, load 60%) of a medium rotating speed and moderate duty, adjust the air fuel ratio pre-control, the regulated quantity fr that makes the Lambda closed loop control is around 1.0 fluctuations up and down.

According to foregoing method, measure the dead time t that determines this operating point _d(test result: t _d=0.1375s), and according to dead time t _dTarget deviation Δ L (BOSCH match-on criterion: 3%), determine the I part and the P part of closed loop control with the Lambda closed loop control.KFRP is 2.7, KFRI is 21.67, for the influence of avoiding interpolation causes difference between calibration value and the practical function value, should (annotate: the arteries and veins spectrum be meant that the corresponding different condition of Control Parameter need get different values with the arteries and veins of these two parameters spectrum, be set in advance in the parameter under the different condition, according to the suitable Control Parameter of different conditional searches, as to above-mentioned two Control Parameter, rotating speed and the different then values of load are also different in actual moving process for electric injection system) in institute be set as unified value a little.

0ms, 100ms, 200ms, 300ms, 400ms, 500ms, 600ms, 700ms, 800ms, 900ms, 1000ms will be made as successively retard time of oxygen sensor deterioration emulator, measure respectively, measurement time need guarantee the control cycle more than 30, the mean value of closed loop control cycle tpotv is as the measured value of Lambda control cycle, and compares with calculated value.

Test result is as shown in table 1:

The test result of table 1 checking deterioration analogue delay following cycle of situation calculated value accuracy

td	0.1375	KFRP	2.7	KFRI	21.67	Ratio correction coefficient	10％
								nmot	3000	rl	60％
t_delay (s)	tp_cal (s)	tp_mea sure (s)	deviatio n(％)	error of t_delay(s)	error of t_delay(％)	tp_cal_cor (s)	deviation after correction (％)

0.000	0.305	0.314	3.18％			0.314
								0.100	0.705	0.761	8.07％	0.0142	14.22％	0.745	2.27％
0.200	1.105	1.173	6.16％	0.0170	8.51％	1.185	-1.01％
								0.300	1.505	1：643	9.18％	0.0345	11.51％	1.625	1.11％
0.400	1.905	2.085	9.45％	0.0450	11.25％	2.065	0.97％
								0.500	2.305	2.454	6.49％	0.0374	7.48％	2.505	-2.01％
0.600	2.705	2.960	9.43％	0.0637	10.62％	2.945	0.51％
								0.700	3.105	3.400	9.52％	0.0739	10.55％	3.385	0.46％
0.800	3.505	3.853	9.95％	0.0871	10.89％	3.825	0.75％
								0.900	3.905	4.240	8.59％	0.0839	9.32％	4.265	-0.57％
1.000	4.305	4.540	5.47％	0.0589	5.89％	4.705	-3.50％

From table 1 and Fig. 8 as can be seen, there are certain difference in measured value and calculated value, and measured value is all greater than calculated value, and has the linear trend that increases with both difference of increase of retard time, and proportional jitter (difference/calculated value) is at (table 1 the 4th row) about in the of 9%.

Error analysis according to this predication method of front, if think this difference all be control deviation by oxygen sensor deterioration emulator cause (think that other are near 1.0 influence factors such as uncertainty as the unstability of pre-control air fuel ratio and lambda sensor characteristic at Lambda, eliminated influence) by a plurality of control cycles average, that is to say, the difference of the retard time of setting and the retard time of oxygen sensor deterioration emulator practical function, according to formula 7, can draw the size (table 1 the 5th row) of this species diversity, also be linear increasing as can be seen basically with the increase of retard time.Calculate its proportional jitter (difference/retard time), about 10% (table 1 the 6th row) substantially, Fig. 9 represents the proportional jitter of the oxygen sensor deterioration emulator control under the different deterioration analogue delay times.

Above-mentioned test result has also been verified guess before this, the control deviation of oxygen sensor deterioration emulator is a proportional jitter, that is to say that oxygen sensor deterioration emulator is proportional to the absolute magnitude of the control deviation of deterioration analogue delay time and the retard time of setting.From the test result of this test, be used for the retard time long about 10% that will set retard time of working control of the oxygen sensor deterioration emulator of this test.

The 7th classifies the calculated value that has compensated the Lambda control cycle after this part deviation as in the table 1, and this calculated value and measured value are very identical as can be seen.The 8th row have reflected the calculated value and the proportional jitter between the actual measured value (difference/revised calculated value) of revised Lambda control cycle in the table 1, as can be seen, deviation is substantially in 3%, maximum deviation is 3.5% only, and be the measuring point of 1000ms the retard time that occurs in setting.The analysis to measure file is found, when be 900ms the retard time of setting, the regulated quantity of closed loop control had reached CLV ceiling limit value in dense side, for no other reason than that when 900ms the regulated quantity of closed loop control to maintain time of CLV ceiling limit value very short, only be 0.06s, so little to the test result influence; And when 1000ms, the time that the regulated quantity of closed loop control maintains CLV ceiling limit value has reached 0.16s.From last surface analysis, can obtain, the Lambda closed loop control cycle is identical with the time that it maintains on the limit value because of regulated quantity reaches the time that limit value shortens, therefore, if on the basis of this measuring point Lambda closed loop control period measurement value, add 0.16s, only be-0.1% then through the calculated value in revised Lambda closed loop control cycle and the proportional jitter of measured value.Like this, the calculated value of revised Lambda control cycle and the proportional jitter between the actual measured value are all in 2.5%.

From above-mentioned test result, can reach a conclusion: the projectional technique in the Lambda closed loop control cycle after above-mentioned lambda sensor (cycle) deterioration is accurately and reliably, has also proved the true property of ending of necessity that oxygen sensor deterioration emulator is calibrated the control deviation of deterioration analogue delay time and above-mentioned oxygen sensor deterioration emulator control deviation calibration steps based on the Lambda closed loop control conversely.Through after the calibration of said method, just can guarantee to adopt different simulators can access the identical actual deterioration analogue delay time, in the following table 2 respectively with control deviation for+10% and-10% oxygen sensor deterioration emulator the setting of the different retard time that need carry out the same target deterioration analogue delay time is described.

The setting of deterioration analogue delay time under the different simulator control deviations of table 2.

Simulator Nr.	Deviation(％)	Objective delay time(ms)	Setting delay time(ms)	Actual delay time(ms)
					1	+10％	400	364	400.4
2	-10％	400	444	399.6

From last table 2 as can be seen, as long as can set the time of deterioration analogue delay according to the control deviation of different oxygen sensor deterioration emulators, just can obtain the deterioration analogue delay time of the reality identical, make and adopt different oxygen sensor deterioration emulators can access identical test result with target simulation retard time.And if do not carry out above-mentioned calibration, above-mentioned two oxygen sensor deterioration emulators are when the same degradation failure of simulation, target deterioration analogue delay time 400ms in as above showing, the actual deterioration analogue delay time will differ about 80ms, and this will cause the very big difference of final test result.

The step of carrying out calibration test is basic identical with above-mentioned demonstration test, for making things convenient for software to design and eliminating as far as possible that random error has some concrete requirements to the influence of test result to process of the test in the process of the test.

The step of carrying out calibration test and analysis is as follows:

The operating point of step 1, medium rotating speed of selection and moderate duty (as 3000 rev/mins of rotating speeds, load 60%) is to guarantee the stability of operating mode.In test after this, the rotating speed load need remain unchanged, because the variation of operating mode will bring the variation in Lambda closed loop control dead time, brings influence to test result.

Step 2, the P part of Lambda closed loop control is set, I part (I=Δ L/t is set according to dead time of this operating point according to 90% of target deviation _d).Ordinary circumstance is provided with consistently through the P part of demarcating back Lambda closed loop control and I part with above-mentioned, can directly adopt the setting in the arteries and veins spectrum, only whole arteries and veins is composed the value that is made as this operating point, to avoid the influence of interpolation.

Step 3, adjustment air fuel ratio pre-control make that Lambda closed loop control regulated quantity fr is to fluctuate up and down in the center with 1.0, avoids this regulated quantity to arrive limit value too early, thereby has reduced the quantity of effective measuring point.

Behind step 4, the abundant warming-up of motor, the beginning measuring recording.The parameter of experimental measurement record should comprise at least: rotation speed n mot, load rl, closed loop control regulated quantity fr, upstream oxygen sensor voltage usvk and the Lambda closed loop control cycle tpotv that rejects the tv part.For the convenience of Software tool design, sample frequency need be set to 10ms.

The deterioration analogue delay time with oxygen sensor deterioration emulator is made as 0 earlier, maintains following a period of time of normal condition (more than the 30s), and Software tool will obtain the Lambda closed loop control cycle under the normal condition by the measurement of this part.

Successively the deterioration analogue delay time is made as 100ms, 200ms, 300ms, 400ms, 500ms, 600ms, 700ms, 800ms, 900ms, 1000ms then.Each measuring point need be guaranteed the Lambda closed loop control cycle more than 30 equally, to guarantee enough samples, eliminates the said stochastic factor in front.

Preserve after step 5, measurement are finished and measure file, just can carry out software analysis then.

Step 6, operate to the software of described measurement file exploitation, click " ... " order button is selected measurement file just now.Click " reading to measure file " order button, software will read in this measurement file, and at this moment, software will show engine operating condition point parameter and diagram Lambda closed loop control regulated quantity fr and control cycle tpotv.

The parameter of step 7, input Lambda closed loop control: P part, I part, the upper limit of regulated quantity and the lower limit of regulated quantity.Click " calculating " order button, carry out analytical calculation.Software tool will calculate the calculated value in the Lambda closed loop control cycle under the different deterioration analogue delay times automatically, detect the measured value in the Lambda closed loop control cycle of each measuring point, and the ratio value that calculates the control deviation of each measuring point, and the proportional jitter of effective measuring point averaged, obtain the control deviation of this oxygen sensor deterioration emulator.Relevant analysis result all is presented in the chart on software interface right side, and final result is presented in the text box above the right side.

Referring to shown in Figure 11, the described method of the measurement file being analyzed for the software of measuring the file exploitation is as follows:

Step 1, the P that reads in the Lambda closed loop control and its upper lower limit value of I parameter meter.

Step 2, read in the data of measuring file.

Step 3, detect the measurement time (for example 20s) under the no delay situation, when smaller or equal to the measurement time of setting, then show error message 1; Execution in step 4 then when greater than the measurement time set.Error message 1 is " measurement time a deficiency under the no delay situation! ".If measurement time falls short of under undelayed situation, then can have influence on the Lambda closed loop control cycle accuracy (influence of random factor can not be eliminated fully) of measuring the operating point basis, will follow-up calculating be had a negative impact, therefore, software will be in the calculating of carrying out next step under this kind situation, finishes to analyze.

The average Lambda closed loop control cycle under step 4, the no delay situation of calculating.

Step 5, the maximum significant figure of calculating strong point number n um_point.

Step 6, when less than the maximum significant figure strong point number n um_point that sets, then show error message 2, finish to analyze.When more than or equal to the maximum significant figure strong point number n um_point that sets, then execution in step 7.

According to Lambda closed loop control cycle t under the no delay situation _p, and Control Parameter P part and I part, can extrapolate and work as t _DelayGreater than how many times, the regulated quantity of Lambda closed loop control will reach limit value certainly, for this reason can confirmed test measuring point (referring to formula 11) which be invalid certainly, to these invalid measuring points, will not carry out analytical calculation.

2* Δ L=P+I* (t _p+ 2*t _Delay) (fr _Max-fr _Min) ... ... ... (formula 11)

Error message 2 is for " the I part causes the significant figure strong point too greatly very little, please reduce the test again of I part! ".For avoiding of the influence of indivedual measuring point random errors, need to adopt the influence of on average eliminating these random errors of a plurality of measuring points to final result.If but from this step analysis, just find that effective measuring point is fewer, and will certainly cause random error that result's influence is strengthened, therefore, under this kind situation, software also can stop next step calculating.Here, effectively the quantity of measuring point is few, means that the increase closed loop control regulated quantity along with the deterioration analogue delay time has reached limit value quickly, and most probable reason is that the I part is too big, therefore, need reduce to test again after the I part.

Step 7, the measuring point quantity i that has finished analysis are set to zero, even i=0.

The time period that step 8, search i+1 measuring point are measured.

Step 9, when this time period during less than setting value, then show error message 3, and transfer to step 12.When this time period during more than or equal to setting value, execution in step 10.Error message 3 is " certain time delay measurements deficiency of time ".Under this kind situation, think and can not fully eliminate stochastic factor, therefore, software can not calculate this measuring point, and it is invalid that this measuring point will be marked as.

Step 10, calculating are the Lambda closed loop control cycle average under retard time with this time period.

Step 11, judge that whether condition for validity satisfies.When effective condition did not satisfy, then execution in step 12, execution in step 13 then when effective condition satisfies.

Judging whether condition for validity satisfies comprises: whether the operating mode of motor (rotating speed and load) fluctuates, and rotating speed surpasses 100l/min with respect to detected rotation speed change under the no delay situation, and load variations is above 2%, then this data point will be marked as invalid; Lambda closed loop control regulated quantity reaches limit value in addition, and it is invalid that this measuring point also can be marked as; In this case, software still can detect and control deviation is calculated the closed loop control cycle under this retard time.Control deviation also can be presented among the axle figure of upper right side shown in Figure 1, and identifies with red circle.But this measuring point will can not used

In the calculating of final simulator control deviation (a plurality of measuring points average).

Step 12, measuring point is made invalid flag, execution in step 13 then.

Step 13, the measuring point quantity i that will finish analysis add 1.

Step 14, judge whether to reach the maximum significant figure strong point number n um_point of setting, when not reaching, then transfer to step 8; Execution in step 15 then when reaching.

The proportional jitter of step 15, the effective measuring point of calculating.

Step 16, the average proportional jitter (control deviation) of calculating oxygen sensor deterioration emulator.

Step 17, the final analysis result of demonstration.The final oxygen sensor deterioration emulator control deviation that calculates will be represented with the form of percentage, and represent overgauge and negative deviation respectively with "+" and "-".

More than by embodiment the present invention has been done detailed explanation, but these are not to be construed as limiting the invention.Those skilled in the art also can make some distortion and improvement under the situation that does not break away from the principle of the invention, these also should be considered as protection scope of the present invention.

Claims (5)

1, a kind of calibration steps of the oxygen sensor deterioration emulator control deviation based on Lambda control, it is characterized in that: measure the value of Lambda closed loop control cycle under the different deterioration analogue delay times, and resultant measured value compared with the calculated value of Lambda closed loop control cycle under the different deterioration analogue delay times respectively, obtain the difference of measured value and calculated value, and calculate the control deviation of oxygen sensor deterioration emulator according to this difference, according to this control deviation described oxygen sensor deterioration emulator is calibrated.

2, the method for claim 1 is characterized in that: described control deviation is a proportional jitter.

3, the method for claim 1 is characterized in that: the method for the described measurement value of Lambda closed loop control cycle under the different deterioration analogue delay times is:

The operating point of step 1, a motor steady running of selection;

Step 2, the P part of Lambda closed loop control is set, the I part is set, I=△ L/t according to dead time of described operating point according to 90% of target deviation _d

Step 3, adjustment air fuel ratio pre-control make that Lambda closed loop control regulated quantity fr is to fluctuate up and down in the center with 1.0;

Behind step 4, the abundant warming-up of motor, the beginning measuring recording; The parameter of measuring recording should comprise at least: rotation speed n mot, load rl, closed loop control regulated quantity fr, upstream oxygen sensor voltage usvk and the Lambda closed loop control cycle tpotv that rejects the tv part; Sample frequency is 10ms.

The deterioration analogue delay time with oxygen sensor deterioration emulator is made as 0 earlier, maintains following a period of time of normal condition, by the measurement of this part, obtains the Lambda closed loop control cycle under the normal condition;

Successively the deterioration analogue delay time is made as 100ms, 200ms, 300ms, 400ms, 500ms, 600ms, 700ms, 800ms, 900ms, 1000ms then; Each measuring point need be guaranteed the Lambda closed loop control cycle more than 30;

Preserve after step 5, measurement are finished and measure file.

4, method as claimed in claim 3 is characterized in that: the method that described measurement file is analyzed controlled deviation is:

Step 1, the P that reads in the Lambda closed loop control and its upper lower limit value of I parameter meter;

Step 2, read in the data of measuring file;

Step 3, detect the measurement time under the no delay situation, when smaller or equal to the measurement time set, then show error message 1, finish analysis;

The average Lambda closed loop control cycle under step 4, the no delay situation of calculating;

Step 5, the maximum significant figure of calculating strong point number n um_point;

Step 6, when less than the maximum significant figure strong point number n um_point that sets, then show error message 2, finish to analyze; When more than or equal to the maximum significant figure strong point number n um_point that sets, then execution in step 7;

Step 7, the measuring point quantity i that has finished analysis are set to zero, even i=0;

The time period that step 8, search i+1 measuring point are measured;

Step 9, when this time period during less than setting value, then show error message 3, and transfer to step 12; When this time period during more than or equal to setting value, execution in step 10;

Step 10, calculating are the Lambda closed loop control cycle average under retard time with this time period;

Step 11, judge that whether condition for validity satisfies, when effective condition did not satisfy, then execution in step 12, execution in step 13 then when effective condition satisfies;

Step 12, measuring point is made invalid flag, execution in step 13 then;

Step 13, the measuring point quantity i that will finish analysis add 1;

Step 14, judge whether to reach the maximum significant figure strong point number n um_point of setting, when not reaching, then transfer to step 8; Execution in step 15 then when reaching;

The proportional jitter of step 15, the effective measuring point of calculating;

Step 16, the average control deviation of calculating oxygen sensor deterioration emulator.

5, method as claimed in claim 4, it is characterized in that: whether the described condition for validity of step 11 comprises: whether the operating mode of motor fluctuates, rotating speed surpasses 100 l/min with respect to detected rotation speed change under the no delay situation, load variations surpasses 2%, then this data point will be marked as invalid; Lambda closed loop control regulated quantity fr reaches limit value, it is invalid that this measuring point also can be marked as, but in this case, still the closed loop control cycle under this retard time is detected and control deviation is calculated, and in the chart of software interface, this measuring point is added red circle and represent.

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