CN103149032B - Dynamic detection method of engine exhaust pressure and flux - Google Patents

Abstract

The invention provides a dynamic detection method of engine exhaust pressure and flux and belongs to the technical field of an automobile engine. A problem that engine bigger errors are estimated by an engine electronic control unit (ECU) in the prior art under the instantaneous conditions is solved. The engine ECU is used for receiving an air inlet variavle valve timing (VVT) camshaft position sensor, an exhaust VVT camshaft position sensor, an air inlet manifold pressure sensor, an air damper valve body sensor and an exhaust manifold pressure dynamic model, wherein the air inlet VVT camshaft position sensor is used for detecting a VVT phase, the exhaust VVT camshaft position sensor is used for detecting an exhaust VVT phase, the air inlet manifold pressure sensor is used for detecting the air inlet manifold pressure, the air damper valve body sensor is used for detecting the position of the air damper valve body and the exhaust manifold pressure dynamic model is used for detecting signals sent by a revolution speed transducer of the motor and sending signal assignments to the engine ECU. And the exhaust manifold pressure is obtained through the exhaust manifold pressure dynamic model, the value is accurate and easy to implement.

Description

A kind of engine exhaust pressure and flow dynamics detection method

Technical field

The invention belongs to technical field of automobile engine, relate to a kind of engine exhaust pressure and flow dynamics detection method

Background technology

Variable Valve Timing Technique of IC Engine, referred to as VVT, in the last few years by the one in the new technology that is applied to gradually in Modern Car, its VVT VVT passes through control and the executive system of outfit, the phase place of engine cam is regulated, thus make valve opening, the time of closedown changes with the change of engine speed, improves charge, coefficient of charge is increased, and the moment of torsion of engine and power can be further improved.

Engine exhaust manifold pressure information has very important status in the ECU (Electrical Control Unit) and ECU of engine.Engine rig test shows, volume efficiency the having a strong impact on by exhaust main pressure of engine suction, and exhaust main pressure is lower, larger at certain admission pressure lower cylinder charge flow rate; Meanwhile, exhaust main pressure is higher, and exhaust gas recirculation amount is larger, this residual waste gas quantity that will directly have influence in cylinder, then determines mixture combustion quality in cylinder.There is at present the exhaust main pressure stable state computation model of a series of maturation, be used for estimating the exhaust main pressure under steady working condition and extraction flow on finished car.But, these mathematics model of stable state can not well be estimated at transient condition, when such as air throttle sudden change and VVT sudden change, the change of exhaust main pressure, causes ECU cannot estimate out the information such as charge flow rate and burning quality exactly when these transient conditions then.On the other hand, for cost-saving, the sensor that production engine one general configuration is very limited, can not configure exhaust main pressure and the flow sensor of high response speed usually.The exhaust main pressure of the engine that in current existing technology, engine electric-controlled unit is estimated by limited sensor information under each transient condition and flow value error comparatively large, not accurate enough.

Prior art is compared, and engine exhaust pressure of the present invention and flow dynamics detection method have the following advantages:

1, the present invention can correctly estimate the exhaust main pressure of engine under each transient condition and flow value by limited sensor information, press states model by the new exhaust main of deriving to be improved largely on the transient changing estimation precision of exhaust main pressure and flow, transient state exhaust main pressure error is reduced to 0.19% from original 2.1%, and makes transient state extraction flow estimation error drop to 1.4% from original 4.2%.

2, the exhaust main that the present invention proposes presses states model and is carrying out timing signal to constant undetermined, and process is simple, can continue to use existing engine pedestal test data.

3, the present invention does not need to install on the engine exhaust main pressure transducer and just can realize, do not need to install in detection mode at original engine to make any adjustments yet, just can obtain exhaust main pressure more accurately, right engine plays conclusive effect to the control of mixture combustion quality in motor cylinder block further.

Summary of the invention

The present invention is directed to existing technology and there are the problems referred to above, propose a kind of engine exhaust pressure and flow dynamics detection method, the method can correctly estimate the exhaust main pressure of engine under each transient condition and tailpipe flow by limited sensor information, and value degree of accuracy is high and easy to implement.

The present invention is realized by following technical proposal: a kind of engine exhaust pressure and flow dynamics detection method, it is characterized in that, the air inlet VVT CMPS Camshaft Position Sensor for detecting air inlet VVT phase place is received respectively by Engine ECU, for detecting the exhaust VVT CMPS Camshaft Position Sensor of exhaust VVT phase place, for detecting the intake manifold pressure sensor of air-distributor pressure, for detect throttler valve body position throttler valve body sensor and for detect engine speed speed probe conveying signal, simultaneously by these signal assignment to the exhaust main pressure in Engine ECU and tailpipe flow dynamics model, and draw exhaust main pressure and tailpipe flow by above-mentioned exhaust main pressure and tailpipe flow dynamics model.

Be equipped with on the engine on the basis of air inlet VVT CMPS Camshaft Position Sensor, exhaust VVT CMPS Camshaft Position Sensor, intake manifold pressure sensor, throttler valve body sensor and speed probe.The throttle valve body position signalling that the air-distributor pressure signal that the exhaust VVT phase signal that the air inlet VVT phase signal that air inlet VVT CMPS Camshaft Position Sensor detects, exhaust VVT CMPS Camshaft Position Sensor detect, intake manifold pressure sensor detect, throttler valve body sensor detect and the engine rotational speed signal that speed probe detects flow to Engine ECU respectively, and Engine ECU applies on exhaust main pressure and tailpipe flow dynamics model according to the above-mentioned detection signal assignment accepted and accurately estimates exhaust main pressure.The method does not need to install exhaust main pressure transducer on the engine and just can realize, do not need to install in detection mode at original engine to make any adjustments yet, just can obtain exhaust main pressure more accurately, determine engine further to the control of mixture combustion quality in motor cylinder block.

In above-mentioned engine exhaust pressure and flow dynamics detection method, described exhaust main pressure and tailpipe flow dynamics model as follows:

${\stackrel{\·}{P}}_{\mathrm{em}}=\frac{R_{\mathrm{em}}{T}_{\mathrm{em}}}{V_{\mathrm{em}}}({\stackrel{\·}{m}}_{\exp }-{\stackrel{\·}{m}}_{\mathrm{pipe}})...\left(1\right)$

${\stackrel{\·}{m}}_{\mathrm{pipe}}={\mathrm{\α}}_{\mathrm{pipe},0}+{\mathrm{\α}}_{\mathrm{pipe},1}{P}_{\mathrm{em}}+{\mathrm{\α}}_{\mathrm{pipe},2}{P_{\mathrm{em}}}^2+{\mathrm{\α}}_{\mathrm{pipe},3}{T}_{\mathrm{em}}...\left(2\right)$

$\begin{array}{c}{\stackrel{\·}{m}}_{\mathrm{cyl}}={\mathrm{\α}}_{\mathrm{cyl}0}+{\mathrm{\α}}_{\mathrm{cyl}1}{p}_{\mathrm{im}}+{\mathrm{\α}}_{\mathrm{cyl}2}N+{\mathrm{\α}}_{\mathrm{cyl}3}{N}^2+{\mathrm{\α}}_{\mathrm{cyl}4}{p}_{\mathrm{im}}N+{\mathrm{\α}}_{\mathrm{cyl}5}{\left(p_{\mathrm{im}}N\right)}^2+\\ {\mathrm{\α}}_{\mathrm{cyl}6}{\mathrm{VVT}}_i+{\mathrm{\α}}_{\mathrm{cyl}7}{\mathrm{VVT}}_i^2+{\mathrm{\α}}_{\mathrm{cyl}8}{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i^2{\mathrm{VVT}}_e\end{array}...\left(3\right)$

In formula, for exhaust main pressure; R _emrepresent engine revolution; V _emrepresent throttle opening; T _emrepresent cylinder exhaust house steward temperature; represent cylinder exhaust port flow, its value equals cylinder air inlet flow under metastable state represent tailpipe flow; P _emrepresent exhaust manifold pressure, its value equals exhaust main pressure p _imrepresent inlet manifold pressure; N represents engine speed; VVT _irepresent air inlet VVT phase place; VVT _erepresentative exhaust VVT phase place; α _cyli, i=1,2 ..., be 10. constant; α _{pipe, i}, i=1,2, be 3. constant.

As can be seen from formula (1), suppose R _emrepresent engine revolution; V _emrepresent throttle opening; T _emrepresent cylinder exhaust house steward temperature certain, as long as determining cylinder air inlet flow and cylinder exhaust main temperature, only there is with the variable quantity of cylinder air inlet flow and tailpipe flow the relation determined in exhaust exhaust main pressure change, thus derive formula (2), the constant number α in formula (2) _{pipe, i}, i=1,2,3. demarcated by the real data of engine pedestal and draw.Afterwards Engine ECU applies on exhaust main pressure and tailpipe flow dynamics model according to the detection signal assignment accepted and accurately estimates exhaust main pressure, representing tailpipe flow and exhaust main pressure and tailpipe flow dynamics model under identical formula exists as the relation in formula 2, then when formula (2) substitute into formula (1) to disappear in formula (1) amount then obtains exhaust main pressure model, when formula (1) P _emsubstitute into the P that formula (1) disappears in formula (1) _emamount then obtains tailpipe discharge model.

In above-mentioned engine exhaust pressure and flow dynamics detection method, described cylinder exhaust port flow equal at metastable state lower cylinder air intake opening flow as long as one of them knowing cylinder exhaust port flow or metastable state lower cylinder air intake opening flow here just can derive above-mentioned formula, and to cylinder air inlet flow also very important in the control procedure of Engine ECU, and in existing Engine ECU, also there is metastable state lower cylinder air intake opening data on flows and so provide more convenient, simple for the data of the foundation of this exhaust main pressure and tailpipe flow dynamics model.

In above-mentioned engine exhaust pressure and flow dynamics detection method, the constant α in described exhaust main pressure and tailpipe flow dynamics model formation (3) _cylii=1,2,10. obtain as follows: carry out measuring for j time obtaining the variable data in j group formula (3) by the cylinder air inlet flow sensor on threst stand, engine speed sensor, inlet manifold sensor, air inlet VVT CMPS Camshaft Position Sensor and exhaust VVT CMPS Camshaft Position Sensor, after these variable data are arranged in matrix union, obtain the constant α in exhaust main pressure and tailpipe flow dynamics model formation (3) _cyli, i=1,2 ..., 10..Here measure obtain in cylinder air inlet temperature model formula (3) constant α to be calibrated after j group data fitting by the actual characteristic on engine test stand _cyli, i=1,2 ..., 10..

In above-mentioned engine exhaust manifold pressure and tail pipe flow dynamics detection method, by individual for j above-mentioned cylinder air inlet flow be arranged in the matrix of j Χ 1 by the inlet manifold pressure p measured _im, engine speed N, air inlet VVT phase place VVT _iwith exhaust VVT phase place VVT _eten variablees formed line up the matrix of j Χ 10 matrix ten variablees be classified as in formula (3), behavior j is capable, by matrix divided by matrix namely the matrix of 10 above-mentioned Χ 1 is obtained this matrix in ten constants be constant α in exhaust main pressure and tailpipe flow dynamics model _cyli, i=1,2 ..., 10..The result showed by the matrix form of multivariate least square method in the j group experimental data that known engine stand is different can draw the constant α in cylinder air inlet temperature model formula (3) as mentioned above _cyli, i=1,2 ..., 10..

In above-mentioned engine exhaust pressure and flow dynamics detection method, the constant α in described exhaust main pressure and tailpipe flow dynamics model formation (2) _{pipe, i}i=1,2,3. obtain as follows: carry out measuring for j time obtaining the variable data in j group formula (2) by the exhaust main pressure transducer on threst stand and exhaust manifold pressure sensor, after these variable data are arranged in matrix union, obtain the constant α in exhaust main pressure and tailpipe flow dynamics model formation (2) _{pipe, i}, i=1,2,3..

In above-mentioned engine exhaust pressure and flow dynamics detection method, by the tailpipe flow in j variable data be arranged in the matrix of j Χ 1 by the cylinder exhaust house steward temperature T in variable data _emwith exhaust manifold pressure p _emtwo Variables to line up be the matrix of j Χ 4 matrix be classified as cylinder exhaust house steward temperature T _emwith exhaust manifold pressure p _em, behavior j is capable, by matrix divided by matrix namely the matrix of 3 above-mentioned Χ 1 is obtained this matrix in three constants be constant α in exhaust main pressure and tailpipe flow dynamics model _{pipe, i}, i=1,2,3..In actual calibration process, only need to gather j measurement data, and each variable is different when each measurement, obtains the constant α in exhaust main pressure and tailpipe flow dynamics model formation (2) so by the way after matching _{pipe, i}, i=1,2,3..

In above-mentioned engine exhaust pressure and flow dynamics detection method, described j group data acquisition multivariate least square method carrys out matching makes each group data when each measurement all different.The demarcation of undetermined constant is carried out, by obtaining the constant α in exhaust main pressure and tailpipe flow dynamics model after multivariate least square fitting by the j group measurement data measured in different variable situation _{pipe, i}, i=1,2,3..

In above-mentioned engine exhaust pressure and flow dynamics detection method, the cylinder exhaust house steward temperature T in described exhaust main pressure and tailpipe flow dynamics model _emestimated by experimental formula.

Accompanying drawing explanation

Fig. 1 is the structural representation that the present invention calculates exhaust main pressure and flow;

Fig. 2 is the analysis of experimental data figure of tailpipe flow estimation result of the present invention;

Fig. 3 is that tailpipe flow of the present invention and exhaust main pressure estimate that result and actual measured value and existing Engine ECU estimate Comparative result figure.

In figure, 1, Engine ECU; 2, air inlet VVT CMPS Camshaft Position Sensor; 3, VVT CMPS Camshaft Position Sensor is vented; 4, intake manifold pressure sensor; 5, speed probe; 6, throttler valve body sensor.

Embodiment

Be below specific embodiments of the invention, and by reference to the accompanying drawings technical scheme of the present invention be further described, but the present invention is not limited to these embodiments.

As shown in Figure 1, this engine exhaust pressure and flow dynamics detection method receive air inlet VVT CMPS Camshaft Position Sensor 2 for detecting air inlet VVT phase place respectively by Engine ECU 1, for detecting the exhaust VVT CMPS Camshaft Position Sensor 3 of exhaust VVT phase place, for detecting the intake manifold pressure sensor 4 of air-distributor pressure, for detect throttler valve body position throttler valve body sensor 6 and for detect engine speed speed probe 5 carry signal, simultaneously by these signal assignment to the exhaust main pressure in Engine ECU 1 and tailpipe flow dynamics model, and draw exhaust main pressure by above-mentioned exhaust main pressure and tailpipe flow dynamics model.

Exhaust main pressure and tailpipe flow dynamics model as follows:

${\stackrel{\·}{P}}_{\mathrm{em}}=\frac{R_{\mathrm{em}}{T}_{\mathrm{em}}}{V_{\mathrm{em}}}({\stackrel{\·}{m}}_{\exp }-{\stackrel{\·}{m}}_{\mathrm{pipe}})...\left(1\right)$

${\stackrel{\·}{m}}_{\mathrm{pipe}}={\mathrm{\α}}_{\mathrm{pipe},0}+{\mathrm{\α}}_{\mathrm{pipe},1}{P}_{\mathrm{em}}+{\mathrm{\α}}_{\mathrm{pipe},2}{P_{\mathrm{em}}}^2+{\mathrm{\α}}_{\mathrm{pipe},3}{T}_{\mathrm{em}}...\left(2\right)$

$\begin{array}{c}{\stackrel{\·}{m}}_{\mathrm{cyl}}={\mathrm{\α}}_{\mathrm{cyl}0}+{\mathrm{\α}}_{\mathrm{cyl}1}{p}_{\mathrm{im}}+{\mathrm{\α}}_{\mathrm{cyl}2}N+{\mathrm{\α}}_{\mathrm{cyl}3}{N}^2+{\mathrm{\α}}_{\mathrm{cyl}4}{p}_{\mathrm{im}}N+{\mathrm{\α}}_{\mathrm{cyl}5}{\left(p_{\mathrm{im}}N\right)}^2+\\ {\mathrm{\α}}_{\mathrm{cyl}6}{\mathrm{VVT}}_i+{\mathrm{\α}}_{\mathrm{cyl}7}{\mathrm{VVT}}_i^2+{\mathrm{\α}}_{\mathrm{cyl}8}{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i^2{\mathrm{VVT}}_e\end{array}...\left(3\right)$

In formula, for exhaust main pressure; R _emrepresent engine revolution; V _emrepresent throttle opening; T _emrepresent cylinder exhaust house steward temperature; represent cylinder exhaust port flow, its value equals cylinder air inlet flow under metastable state represent tailpipe flow; P _emrepresent exhaust manifold pressure, its value equals exhaust main pressure p _imrepresent inlet manifold pressure; N represents engine speed; VVT _irepresent air inlet VVT phase place; VVT _erepresentative exhaust VVT phase place; α _cyli, i=1,2 ..., be 10. constant; α _{pipe, i}, i=1,2, be 3. constant.I.e. cylinder exhaust port flow equal at metastable state lower cylinder air intake opening flow

Be equipped with on the engine on the basis of air inlet VVT CMPS Camshaft Position Sensor 2, exhaust VVT CMPS Camshaft Position Sensor 3, intake manifold pressure sensor 4, throttler valve body sensor 6 and speed probe 5.The throttle valve body position signalling that the air-distributor pressure signal that the exhaust VVT phase signal that the air inlet VVT phase signal that air inlet VVT CMPS Camshaft Position Sensor 2 detects, exhaust VVT CMPS Camshaft Position Sensor 3 detect, intake manifold pressure sensor 4 detect, throttler valve body sensor 6 detect and the engine rotational speed signal that speed probe 5 detects flow to Engine ECU 1 respectively, and Engine ECU 1 applies on exhaust main pressure and tailpipe flow dynamics model according to the above-mentioned detection signal assignment accepted and accurately estimates exhaust main pressure.

As can be seen from formula (1), suppose R _emrepresent engine revolution; V _emrepresent throttle opening; T _emrepresent cylinder exhaust house steward temperature certain, as long as determining cylinder air inlet flow and cylinder exhaust main temperature, only there is with the variable quantity of cylinder air inlet flow and tailpipe flow the relation determined in exhaust exhaust main pressure change, thus derive formula (2), the constant number α in formula (2) _{pipe, i}, i=1,2,3. demarcated by the real data of engine pedestal and draw.Afterwards Engine ECU applies on exhaust main pressure and tailpipe flow dynamics model according to the detection signal assignment accepted and accurately estimates exhaust main pressure.Representing tailpipe flow and exhaust main pressure and tailpipe flow dynamics model under identical formula exists as the relation in formula 2, then when formula (2) substitute into formula (1) to disappear in formula (1) amount then obtains exhaust main pressure model, when formula (1) P _emsubstitute into the P that formula (1) disappears in formula (1) _emamount then obtains tailpipe discharge model.Wherein, formula (1) is quoted from " international symposium of the 5th electro-mechanical system controls PRELIMINARY RESULTS about optimum VVT and ignition timing "." international symposium of the 5th electro-mechanical system controls PRELIMINARY RESULTS about optimum VVT and ignition timing " is translated by the english literature in following bracket and is obtained (Lee, D., Jiang, Li., Yilmaz, H., Stefanopoulou, A.G. (2010) .preliminary results on optimal variable valve timing and spark timingcontrol via extremum seeking.5th IFAC Symposium on MechatronicSystems).

Constant α in exhaust main pressure and tailpipe flow dynamics model formation (3) _cylii=1,2,, 10. obtain as follows: carry out measuring for j time obtaining the variable data in j group formula (3) by the cylinder air inlet flow sensor on threst stand, engine speed sensor 5, inlet manifold sensor, air inlet VVT CMPS Camshaft Position Sensor 2 and exhaust VVT CMPS Camshaft Position Sensor 3.By individual for j above-mentioned cylinder air inlet flow be arranged in the matrix of j Χ 1 by the inlet manifold pressure p measured _im, engine speed N, air inlet VVT phase place VVT _iwith exhaust VVT phase place VVT _eten variablees formed line up the matrix of j Χ 10 matrix ten variablees be classified as in formula (3), behavior j is capable, by matrix divided by matrix namely the matrix of 10 above-mentioned Χ 1 is obtained this matrix in ten constants be constant α in exhaust main pressure and tailpipe flow dynamics model _cyli, i=1,2 ..., 10..

Constant α in exhaust main pressure and tailpipe flow dynamics model formation (2) _{pipe, i}i=1,2,3. obtain as follows: carry out measuring for j time obtaining the variable data in j group formula (2), by the tailpipe flow in j variable data by the exhaust main pressure transducer on threst stand and exhaust manifold pressure sensor be arranged in the matrix of j Χ 1 by the cylinder exhaust house steward temperature T in variable data _emwith exhaust manifold pressure p _emtwo Variables to line up be the matrix of j Χ 4 matrix be classified as cylinder exhaust house steward temperature T _emwith exhaust manifold pressure p _em, behavior j is capable, by matrix divided by matrix namely the matrix of 3 above-mentioned Χ 1 is obtained this matrix in three constants be constant α in exhaust main pressure and tailpipe flow dynamics model _{pipe, i}, i=1,2,3..

J group data acquisition multivariate least square method carrys out matching makes each group data when each measurement all different.The demarcation of undetermined constant is carried out, by the constant obtaining in exhaust main pressure and tailpipe flow dynamics model after multivariate least square fitting and in tailpipe discharge model by the j group measurement data measured in different variable situation.Least square method is a kind of mathematical optimization techniques.It finds the optimal function coupling of data by the quadratic sum of minimum error.Utilize least square method can try to achieve unknown data easily, and between the data that these are tried to achieve and real data, the quadratic sum of error is minimum.Least square method be used for curve time to data-oriented point as { (Xi, Yi) } (i=0,1,, m), getting in fixed function class Φ, ask p (x) ∈ Φ, make the quadratic sum E^2 of error minimum, E^2=∑ [p (Xi)-Yi] ^2.From geometric meaning, seek exactly with set point { (Xi, Yi) } (i=0,1 ..., square distance m) and be minimum curve y=p (x).Function p (x) is called fitting function or least square solution, asks the method for fitting function p (x) to be called the least square method of curve.Constant to be calibrated of the present invention just to carry out according to above-mentioned least square ratio juris by the real data of the mensuration engine test stand under different variable that matching obtains, and the fitting mode of this multivariable least square method realizes the matching of curve by Matlab computational tool.

Cylinder exhaust house steward temperature simultaneously in exhaust main pressure and tailpipe flow dynamics model is estimated by experimental formula.

The test findings that the exhaust main pressure that the present invention proposes and tailpipe flow dynamics model gather each steady state condition after Engine ECU 1 is tested is as follows:

As shown in Figure 2, this method is by after cylinder intake air flow models applying is in Engine ECU 1, be 1200 to 2000 turns according in operating mode, air inlet VVT is 700 to 1000K, exhaust VVT be 700 to 1000K and the experimental data that draws when being 0.95 to 1.3bar of exhaust main pressure known, in the comparative analysis of experimental data tailpipe flow estimation result of the present invention and actual measured value as Fig. 2, ordinate Y-axis represents tailpipe flow, value range is at 0 ~ 80g/s, horizontal ordinate X-axis represents exhaust main pressure, value range is 0.95 to 1.3bar, in figure, "-" represents the tailpipe flow calculated by improvement front exhaust tail pipe discharge model, "×" represents the tailpipe flow calculated by improvement tailpipe discharge model, "○" represents the tailpipe flow of actual measurement on threst stand, threst stand obtains the exhaust main pressure between 0.95 to 1.3bar, as 1.0bar, this exhaust main pressure values assignment is given the tailpipe discharge model after improving and the tailpipe discharge model before improving, obtain the tailpipe flow under same exhaust main pressure, another tailpipe flow is obtained again on threst stand, as 1.1bar, obtain the tailpipe flow that another is drawn by the tailpipe discharge model improved afterwards and before improving respectively, a series of tailpipe flow drawn by the tailpipe discharge model improved afterwards and before improving is obtained again according to different exhaust main pressure values, above-mentioned test also can directly continue to use existing test figure, only need under equal conditions calculate tailpipe flow by the tailpipe discharge model after improving, known by three above-mentioned tests, the data surveyed of tailpipe discharge model before improvement with experiment measured data along with there is larger error in the change of delivery temperature, particularly delivery temperature estimates that when 700K the error of tailpipe flow is maximum, and the data that the tailpipe discharge model after improving is surveyed are comparatively close with experiment measured data, thus by the cylinder mass flow of these important operating modes estimate situation can find improve after tailpipe discharge model delivery temperature difference change time stable estimation cylinder intake air flow model compared with before-improvement have larger improvement, especially the estimation when delivery temperature is lower is more accurate, and can find that the present invention improves the tailpipe flow of rear calculating and the average error that relatively obtains of actual measured value is 0.61g/s from the data of experiment, can find out that average predictor error drops to 1.4% from original 4.2%.

Fig. 3 is that tailpipe flow of the present invention and exhaust main pressure estimate that result and actual measured value and existing Engine ECU 1 estimate Comparative result figure.As shown in Figure 3, M/g/s axle represents that exhausr port flux unit is g/s; Y/K axle represents that exhaust main temperature unit is K; Z/bar axle represents that exhaust main pressure unit is bar; W/g/s axle represents that tailpipe flux unit is g/s; X/s axle represents that chronomere is s.Fig. 3 is the experimental data tailpipe flow that exhausr port flow draws when 24 to 30g/s and exhaust main temperature are and change within the scope of 990 to 1005K is the 1.04 concrete data arriving within the scope of 1.1bar in 20 to 30g/s and exhaust main pressure, concrete data comprise improve after the exhaust main pressure estimated under this dynamic model and tailpipe data on flows, respectively with improve before dynamic model estimated data and start to test measured data comparative analysis.In figure, "--" represent the exhaust main pressure and tailpipe flow that are calculated by improvement front exhaust tail pipe discharge model, "-" represents by improving the exhaust main pressure and tailpipe flow that final vacuum tail pipe discharge model calculates, and "--" represents exhaust main pressure and the tailpipe flow of actual measurement on threst stand, threst stand obtains the exhaust main temperature between an exhausr port flow and 990 to 1005K between 24 to 30g/s, if figure is the 7th second time, exhausr port flow is approximately 25.5g/s, now corresponding exhaust main temperature is 991K, test measured data exhaust main pressure is 1.065bar and tailpipe flow is 25.6g/s, it is that the assignment of 991K is to the exhaust main pressure model after improving and the exhaust main pressure model before improving that exhausr port flow is approximately 25.5g/s and exhaust main temperature, obtain the exhaust main pressure under same exhaust main temperature and exhausr port flow, it is 1.06bar that exhaust main pressure model estimation after improvement obtains exhaust main pressure, it is 1.049bar that exhaust main pressure model estimation before improvement obtains exhaust main pressure, in like manner exhausr port flow being approximately 25.5g/s and exhaust main temperature is that the assignment of 991K is to the tailpipe discharge model after improving and the tailpipe discharge model before improving, obtain the tailpipe flow under same exhaust main temperature and exhausr port flow, it is 25.5g/s that tailpipe discharge model estimation after improvement obtains tailpipe flow, and it is 24g/s that the tailpipe discharge model estimation before improvement obtains tailpipe flow.

The data plot as Fig. 3 is obtained after repeatedly carrying out above-mentioned test, larger error is there is along with the change of delivery temperature in the data having the tailpipe discharge model before the known improvement of figure to survey with experiment measured data, and the data surveyed of tailpipe discharge model after improving are comparatively close with experiment measured data, improve that exhaust main pressure that final vacuum house steward pressure model calculates represents in the drawings the exhaust main pressure expression in the drawings "--" of "-" line and actual measurement on threst stand be similar to and overlap; The tailpipe flow expression in the drawings "--" improving "-" line that tailpipe flow that final vacuum tail pipe discharge model calculates represents in the drawings and actual measurement on threst stand is similar to and overlaps.Thus estimate situation by tailpipe flow and house steward's pressure of these important operating modes and can find that the tailpipe flow of the estimation tailpipe discharge model estimation compared with before-improvement when the different change of delivery temperature of the tailpipe discharge model after improving is closer to experimental test value, especially transient state extraction flow estimation result is more accurate, and can find that the average predictor error of transient state extraction flow that the tailpipe throughput ratio improvement front exhaust tail pipe discharge model that the present invention improves rear estimation is estimated drops to 1.4% from original 4.2% from the data of experiment.

Simultaneously estimate situation by cylinder exhaust flow and the pressure of these important operating modes and can find that the exhaust main pressure of the estimation exhaust main pressure model estimation compared with before-improvement when the different change of exhaust main temperature of the exhaust main pressure model after improving is closer to experimental test value, especially transient state exhaust main pressure estimation result is more accurate, and compares from the data of experiment and can find that the exhaust main pressure that the present invention improves rear estimation drops to 0.19% than the average predictor error of transient state exhaust main pressure improving the estimation of front exhaust house steward pressure model from original 2.1%.

In sum, the present invention improves transient state exhaust main pressure and the transient state tailpipe flow value degree of accuracy more of Engine ECU 1 estimation under the different change of exhaust main temperature of exhaust main pressure model and tailpipe discharge model, reduce error, can follow close to the actual numerical value under generator operating conditions.Volume efficiency the having a strong impact on by exhaust main pressure of engine suction, exhaust main pressure is lower, larger at certain admission pressure lower cylinder charge flow rate; Meanwhile, exhaust main pressure is higher, and exhaust gas recirculation amount is larger, this residual waste gas quantity that will directly have influence in cylinder, then determines mixture combustion quality in cylinder.Estimate that exhaust main pressure and the further control of tailpipe flow to Engine ECU 1 serve very important effect as can be seen here more accurately.

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendment or supplement or adopt similar mode to substitute to described specific embodiment, but can't depart from spirit of the present invention or surmount the scope that appended claims defines.

Although more employ the terms such as Engine ECU 1, air inlet VVT CMPS Camshaft Position Sensor 2, exhaust VVT CMPS Camshaft Position Sensor 3, intake manifold pressure sensor 4, speed probe 5, throttler valve body sensor 6 herein, do not get rid of the possibility using other term.These terms are used to be only used to describe and explain essence of the present invention more easily; The restriction that they are construed to any one additional is all contrary with spirit of the present invention.

Claims (9)

1. an engine exhaust pressure and flow dynamics detection method, it is characterized in that, the air inlet VVT CMPS Camshaft Position Sensor (2) for detecting air inlet VVT phase place is received respectively by Engine ECU (1), for detecting the exhaust VVT CMPS Camshaft Position Sensor (3) of exhaust VVT phase place, for detecting the intake manifold pressure sensor (4) of air-distributor pressure, for detecting the signal that the throttler valve body sensor (6) of throttler valve body position and the speed probe (5) for detecting engine speed are carried, simultaneously by these signal assignment to the exhaust main pressure in Engine ECU (1) and tailpipe flow dynamics model, and draw exhaust main pressure and tailpipe flow by above-mentioned exhaust main pressure and tailpipe flow dynamics model.

2. engine exhaust pressure according to claim 1 and flow dynamics detection method, is characterized in that, described exhaust main pressure and tailpipe flow dynamics model as follows:

${\stackrel{.}{P}}_{\mathrm{em}}=\frac{R_{\mathrm{em}}{T}_{\mathrm{em}}}{V_{\mathrm{em}}}({\stackrel{.}{m}}_{\exp }-{\stackrel{.}{m}}_{\mathrm{pipe}})......\left(1\right)$

${\stackrel{.}{m}}_{\mathrm{pipe}}={\mathrm{\α}}_{\mathrm{pipe},0}+{\mathrm{\α}}_{\mathrm{pipe},1}{P}_{\mathrm{em}}+{\mathrm{\α}}_{\mathrm{pipe},2}{P_{\mathrm{em}}}^2+{\mathrm{\α}}_{\mathrm{pipe},3}{T}_{\mathrm{em}}......\left(2\right)$

$\begin{array}{c}{\stackrel{.}{m}}_{\mathrm{cyl}}={\mathrm{\α}}_{\mathrm{cyl}0}+{\mathrm{\α}}_{\mathrm{cyl}1}{p}_{\mathrm{im}}+{\mathrm{\α}}_{\mathrm{cyl}2}N+{\mathrm{\α}}_{\mathrm{cyl}3}{N}^2+{\mathrm{\α}}_{\mathrm{cyl}4}{p}_{\mathrm{im}}N+{\mathrm{\α}}_{\mathrm{cyl}5}{\left(p_{\mathrm{im}}N\right)}^2+\\ {\mathrm{\α}}_{\mathrm{cyl}6}{\mathrm{VVT}}_i+{\mathrm{\α}}_{\mathrm{cyl}7}{\mathrm{VVT}}_i^2+{\mathrm{\α}}_{\mathrm{cyl}8}{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i{\mathrm{VVT}}_e+{\mathrm{\α}}_{\mathrm{cyl}9}{\mathrm{VVT}}_i^2{\mathrm{VVT}}_e\end{array}......\left(3\right)$

In formula, for exhaust main pressure; R _emrepresent engine revolution; V _emrepresent throttle opening; T _emrepresent cylinder exhaust house steward temperature; represent cylinder exhaust port flow, its value equals cylinder air inlet flow under metastable state represent tailpipe flow; P _emrepresent exhaust manifold pressure, its value equals exhaust main pressure p _imrepresent inlet manifold pressure; N represents engine speed; VVT _irepresent air inlet VVT phase place; VVT _erepresentative exhaust VVT phase place; α _cyli, i=1,2 ..., be 10. constant; α _{pipe, i}, i=1,2, be 3. constant.

3. engine exhaust pressure according to claim 2 and flow dynamics detection method, is characterized in that, described cylinder exhaust port flow equal at metastable state lower cylinder air intake opening flow

4. the engine exhaust pressure according to Claims 2 or 3 and flow dynamics detection method, is characterized in that, the constant α in described exhaust main pressure and tailpipe flow dynamics model formation (3) _cylii=1,2,10. obtain as follows: by the cylinder air inlet flow sensor on threst stand, engine speed sensor (5), inlet manifold sensor, air inlet VVT CMPS Camshaft Position Sensor (2) be vented VVT CMPS Camshaft Position Sensor (3) and carry out measuring for j time obtaining the variable data in j group formula (3), after these variable data are arranged in matrix union, obtain the constant α in cylinder air inlet temperature model formula (3) _cyli, i=1,2 ..., 10..

5. engine exhaust pressure according to claim 4 and flow dynamics detection method, is characterized in that, by individual for j above-mentioned cylinder air inlet flow be arranged in the matrix of j Χ 1 by the inlet manifold pressure p measured _im, engine speed N, air inlet VVT phase place VVT _iwith exhaust VVT phase place VVT _eten variablees formed line up the matrix of j Χ 10 matrix ten variablees be classified as in formula (3), behavior j is capable, by matrix divided by matrix obtain the matrix of 10 Χ 1 this matrix in ten constants be constant α in exhaust main pressure and tailpipe flow dynamics model _cyli, i=1,2 ..., 10..

6. engine exhaust pressure according to claim 5 and flow dynamics detection method, is characterized in that, the constant α in described exhaust main pressure and tailpipe flow dynamics model formation (2) _{pipe, i}i=1,2,3. obtain as follows: carry out measuring for j time obtaining the variable data in j group formula (2) by the exhaust main pressure transducer on threst stand and exhaust manifold pressure sensor, after these variable data are arranged in matrix union, obtain the constant α in exhaust main pressure and tailpipe flow dynamics model formation (2) _{pipe, i}, i=1,2,3..

7. engine exhaust pressure according to claim 6 and flow dynamics detection method, is characterized in that, by the tailpipe flow in j variable data be arranged in the matrix of j Χ 1 by the cylinder exhaust house steward temperature T in variable data _emwith exhaust manifold pressure p _emtwo Variables to line up be the matrix of j Χ 4 matrix be classified as cylinder exhaust house steward temperature T _emwith exhaust manifold pressure p _em, behavior j is capable, by matrix divided by matrix obtain the matrix of 3 Χ 1 this matrix in three constants be constant α in exhaust main pressure and tailpipe flow dynamics model _{pipe, i}, i=1,2,3..

8. engine exhaust pressure according to claim 7 and flow dynamics detection method, is characterized in that, described j group data acquisition multivariate least square method carrys out matching makes each group data when each measurement all different.

9. engine exhaust pressure according to claim 2 and flow dynamics detection method, is characterized in that, the cylinder exhaust house steward temperature T in described exhaust main pressure and tailpipe flow dynamics model _emestimated by experimental formula.