CN102645335B - Method for locating top dead center of six cylinder engine - Google Patents

Abstract

The invention relates to a method for locating the top dead center of a six-cylinder engine. The steps are: (1) installing an acceleration vibration sensor on the six-cylinder engine and connecting it to a computer through a vibration signal acquisition device; (2) collecting vibration response time domain signals of six cylinders; (3) Change into a complex signal; (4) Obtain the characteristic parameters of the combustion shock response of the six cylinders; (5) List the digital quantization matrix: (6) Set the characteristic parameters of the combustion shock response as XA, XB, XC, XD, XE, XF respectively; (7) List each The corresponding matrix of combustion shock response characteristic parameters of the working cylinder ⑻, the elements of each matrix are multiplied and summed, and then compared, the engine working cylinder corresponding to XA in the one with the largest value is the engine working cylinder corresponding to the top dead center. The invention realizes the accurate positioning of the top dead center of the engine, improves the identification speed of the engine failure cylinder, shortens the diagnosis time of the engine failure cylinder, has simple method, is easy to operate, and facilitates the repair and maintenance of the engine.

Description

The method of location six cylinder engine top dead centre

Technical field

The invention belongs to engine art, especially a kind of method of locating six cylinder engine top dead centre.

Background technology

Six cylinder engine is applied more extensive on automobile, when in-engine cylinder body breaks down, mean speed that can calculation engine bent axle and according to the vibratory response characteristic of corresponding each cylinder of engine of top dead centre signal, and by the job order of each working cylinder of engine, 1,5,3,6,2,4, and the duty of each cylinder of shock response characteristic diagnosis and distinguish of corresponding each cylinder of engine and trouble location thereof, type, this just requires top dead center position accurately, could breakdown in the motor cylinder and fault type accurately be located and be diagnosed.The signal acquiring method of conventional top dead centre is that the flywheel of engine is pasted to reflecting piece, by photoelectric sensor, gathers top dead centre signal, and acceleration vibration transducer gathers the acceleration vibration signal that engine cylinder covers measuring point.Top dead centre signal is corresponding with acceleration vibration signal, but in the operation of actual paster, photoelectric sensor is aimed to engine flywheel paster very difficult, and paster is very time-consuming, so be easy to cause the dislocation of corresponding each cylinder of top dead centre signal, to such an extent as to the job order of the acceleration vibration signal gathering and corresponding engine cylinder usually can not be accurately corresponding, carry out according to this running state analysis of each cylinder of engine and very difficult to the Accurate Diagnosis identification of Cylinder.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of method of locating six cylinder engine top dead centre is provided, the method has realized the accurate location to engine tope center, improved the recognition speed of engine failure cylinder, shortened the Diagnostic Time of engine failure cylinder, method is simple, easy to operate, has facilitated the maintenance maintenance of engine.

The present invention solves its technical matters and is achieved through the following technical solutions:

Locate a method for six cylinder engine top dead centre, the step that its method comprises is:

(1), between the first cylinder of six cylinder engine and the second cylinder, arrange between the first measuring point, the second cylinder and the 3rd cylinder and arrange between the second measuring point, the 4th cylinder and the 5th cylinder and arrange between the 3rd measuring point, the 5th cylinder and the 6th cylinder the 4th measuring point is set, one acceleration vibration transducer is installed respectively on each measuring point, and this acceleration vibration transducer connects computing machine by vibration signals collecting instrument;

, gather the acceleration vibration signal that six working cylinders of engine are no less than a dust cycle, obtain the vibratory response time-domain signal of six working cylinders of engine;

(3), the vibratory response time-domain signal of six working cylinders of engine is carried out to Xi Er baud conversion, obtain the complex signal of six working cylinders of engine;

(4), with Gauss's first-harmonic correlativity filtering method, the complex signal of six working cylinders of engine is extracted, obtain the burning shock response characteristic parameter of six working cylinders of engine;

(5), according to the row order of the first measuring point, the second measuring point, the 3rd measuring point, the 4th measuring point, draw the digital quantization matrix A between measuring point and six working cylinders of engine:

Matrix $A=\left[\begin{array}{cccccc}1.0& 0& 0.5& 0& 1.0& 0\\ 0.5& 0& 1.0& 0& 1.0& 0.5\\ 0& 1.0& 0.5& 0.5& 0& 1.0\\ 0& 1.0& 0& 1.0& 0& 0.5\end{array}\right]$

(6), setting engine crankshaft corner is that 0 degree, 120 degree, 240 are spent, 360 degree, 480 are spent, the burning shock response characteristic parameter of 600 degree is respectively XA, XB, XC, XD, XE, XF;

(7), according to the row of XA, XB, XC, XD, XE, XF, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix B;

According to the row of XB, XC, XD, XE, XF, XA, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form Matrix C;

According to the row of XC, XD, XE, XF, XA, XB, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix D;

According to the row of XD, XE, XF, XA, XB, XC, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix E;

According to the row of XE, XF, XA, XB, XC, XD, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix F;

According to the row of XF, XA, XB, XC, XD, XE, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix G;

(8), by each numerical value of matrix A and matrix B one by one after corresponding multiplying each other summation obtain S1;

By each numerical value of matrix A and Matrix C one by one after corresponding multiplying each other summation obtain S2;

By each numerical value of matrix A and matrix D one by one after corresponding multiplying each other summation obtain S3;

By matrix A and each numerical value of matrix E one by one after corresponding multiplying each other summation obtain S4;

By each numerical value of matrix A and matrix F one by one after corresponding multiplying each other summation obtain S5;

By matrix A and each numerical value of matrix G one by one after corresponding multiplying each other summation obtain S6;

, get S1, S2, S3, S4, S5, S6 intermediate value the maximum, engine operation cylinder corresponding to XA in this value the maximum is exactly the engine operation cylinder that top dead centre is corresponding.

And described six cylinder engine is six cylinder diesel motors or six cylinder gasoline engines.

Advantage of the present invention and beneficial effect are:

The method of this location six cylinder engine top dead centre has realized the accurate location to engine tope center, has improved the recognition speed of engine failure cylinder, has shortened the Diagnostic Time of engine failure cylinder, and method is simple, easy to operate, has facilitated the maintenance maintenance of engine.

Figure of description

Fig. 1 is the oscillogram in four continuous working circulations of the first measuring point measured signal.

Embodiment

Below by specific embodiment, the invention will be further described, and following examples are descriptive, is not determinate, can not limit protection scope of the present invention with this.

Locate a method for six cylinder engine top dead centre, the step that its method comprises is:

(1), between the first cylinder of six cylinder engine and the second cylinder, arrange between the first measuring point, the second cylinder and the 3rd cylinder and arrange between the second measuring point, the 4th cylinder and the 5th cylinder and arrange between the 3rd measuring point, the 5th cylinder and the 6th cylinder the 4th measuring point is set, one acceleration vibration transducer is installed respectively on each measuring point, and this acceleration vibration transducer connects computing machine by vibration signals collecting instrument;

, gather the acceleration vibration signal that six working cylinders of engine are no less than a dust cycle, obtain the vibratory response time-domain signal of six working cylinders of engine;

(3), the vibratory response time-domain signal of six working cylinders of engine is carried out to Xi Er baud conversion, obtain the complex signal of six working cylinders of engine;

(4), with Gauss's first-harmonic correlativity filtering method, the complex signal of six working cylinders of engine is extracted, obtain the burning shock response characteristic parameter of six working cylinders of engine;

(5), according to the row order of the first measuring point, the second measuring point, the 3rd measuring point, the 4th measuring point, draw the digital quantization table 1 between measuring point and six working cylinders of engine

Table 1

The digitizing of table 1 is arranged and is write as matrix form, obtain matrix A:

Matrix $A=\left[\begin{array}{cccccc}1.0& 0& 0.5& 0& 1.0& 0\\ 0.5& 0& 1.0& 0& 1.0& 0.5\\ 0& 1.0& 0.5& 0.5& 0& 1.0\\ 0& 1.0& 0& 1.0& 0& 0.5\end{array}\right]$

(6), setting engine crankshaft corner is that 0 degree, 120 degree, 240 are spent, 360 degree, 480 are spent, the burning shock response characteristic parameter of 600 degree is respectively XA, XB, XC, XD, XE, XF;

(7), according to the row of XA, XB, XC, XD, XE, XF, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix B;

According to the row of XB, XC, XD, XE, XF, XA, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form Matrix C;

According to the row of XC, XD, XE, XF, XA, XB, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix D;

According to the row of XD, XE, XF, XA, XB, XC, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix E;

According to the row of XE, XF, XA, XB, XC, XD, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix F;

According to the row of XF, XA, XB, XC, XD, XE, sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one and form matrix G;

(8), by each numerical value of matrix A and matrix B one by one after corresponding multiplying each other summation obtain S1;

By each numerical value of matrix A and Matrix C one by one after corresponding multiplying each other summation obtain S2;

By each numerical value of matrix A and matrix D one by one after corresponding multiplying each other summation obtain S3;

By matrix A and each numerical value of matrix E one by one after corresponding multiplying each other summation obtain S4;

By each numerical value of matrix A and matrix F one by one after corresponding multiplying each other summation obtain S5;

By matrix A and each numerical value of matrix G one by one after corresponding multiplying each other summation obtain S6;

, get S1, S2, S3, S4, S5, S6 intermediate value the maximum, engine operation cylinder corresponding to XA in this value the maximum is exactly the engine operation cylinder that top dead centre is corresponding.Namely the corresponding engine operation cylinder when corresponding working cylinder multiplies each other in matrix A of the XA in this value the maximum is the engine operation cylinder that top dead centre is corresponding.Six cylinder engine in the present embodiment is six cylinder diesel motors, and described six cylinder engine can be also six cylinder gasoline engines.

Take that to choose four working cycle vibratory response time-domain signals be example, its time domain waveform as shown in Figure 1.In order determining accurately, the corresponding engine cylinder number of top dead centre its vibratory response time-domain signal to be transformed to complex signal, then its complex signal to be carried out correlativity filtering and extracted the characteristic parameter of burning shock response.By calculating, extract and draw and sequentially list with each measuring point of matrix A shock response characteristic parameter that burns one to one as follows with the row of XA, XB, XC, XD, XE, XF:

The matrix B forming is $\left[\begin{array}{cccccc}19& 59& 20& 50& 21& 25\\ 20& 62& 51& 23& 21& 60\\ 48& 20& 57& 13& 60& 42\\ 138& 15& 28& 16& 72& 20\end{array}\right]$

By each numerical value of matrix A and matrix B one by one after corresponding multiplying each other summation obtain S1

Be S1=1.0 * 19+0.5 * 20+0 * 48+0 * 138+0 * 59+0 * 62+1.0 * 20+1.0 * 15+0.5 * 20+1.0 * 51+0.5 * 57+0 * 28+0 * 50+0 * 23+0.5 * 13+1.0 * 16+1.0 * 21+1.0 * 21+0 * 60+0 * 72+0 * 25+0.5 * 60+1.0 * 42+0.5 * 20=300

In like manner by each numerical value of matrix A and Matrix C one by one after corresponding multiplying each other summation obtain S2=543.5

By each numerical value of matrix A and matrix D one by one after corresponding multiplying each other summation obtain S3=274.5

By matrix A and each numerical value of matrix E one by one after corresponding multiplying each other summation obtain S4=666.5

By each numerical value of matrix A and matrix F one by one after corresponding multiplying each other summation obtain S5=275.5

By matrix A and each numerical value of matrix G one by one after corresponding multiplying each other summation obtain S6=578.5

The S1 more than calculating, S2, S3, S4, S5, S6 intermediate value the maximum are S4=666.5, according to the corresponding relation in combination, obtaining matching result is: the C1 cylinder in XD homography A, C5 cylinder in XE homography A, C3 cylinder in XF homography A, C6 cylinder in XA homography A, C2 cylinder in XB homography A, the C4 cylinder in XC homography A.Hence one can see that, and top dead centre is corresponding to C6 cylinder, i.e. 6# cylinder; This is with number consistent with the corresponding cylinder that pastes the actual top dead centre that reflecting piece method obtains.Illustrate that the present invention can determine the cylinder number that top dead centre is corresponding accurately and efficiently.Thus, the detection to the duty of each cylinder of engine, provides very important basis to the diagnosis and distinguish of the location of Cylinder, fault type.

Chinese and Western of the present invention that baud conversion computing method and Gauss's first-harmonic correlativity filtering method are method of the prior art.Below sketch the burning shock response parameter extracting method based on the filtering of Gauss's first-harmonic correlativity:

(1) the Xi Er baud conversion of vibratory response time-domain signal, Xi Er baud English is the real signal x (t) that Hilbert considers any vibratory response, can be expressed as:

The vibratory response real signal x (t) recording is converted to its corresponding complex signal, must carry out Hilbert conversion to vibratory response real signal x (t):

$H\left(t\right)=\frac{1}{\mathrm{\π}}{\∫}_{-\∞}^{+\∞}\frac{x\left(\mathrm{\τ}\right)}{t-\mathrm{\τ}}\mathrm{d\τ}---\left(2\right)$

The complex signal that former real signal x (t) is corresponding is Z (t):

In formula (3), A (t) is amplitude function; for phase function.Its expression formula is:

$A\left(t\right)=\sqrt{x{\left(t\right)}^2+H{\left(t\right)}^2},$

Because the vibration signal of actual measurement is grouped into by some one-tenth, x (t) can be expressed as:

x(t)=x ₁(t)+x ₂(t)+…x _i(t)+…i＝1,2,…(4)

In formula (4), x _i(t) can be slow varying signal or unifrequency (strengthening/decay) oscillator signal of amplitude and phase place.And Hilbert conversion is linear transformation, so there is following expression:

(5)

(2) with the filtering of Gauss's first-harmonic correlativity, extract burning shock response characteristic parameter

If the Gauss of unit energy (Gauss) first-harmonic function is:

$A(t,f_c,\mathrm{\α})=\frac{1}{\sqrt{\sqrt{\mathrm{\π}}\mathrm{\α}}}{e}^{2\mathrm{i\πt}{f}_c-\frac{t^2}{2{\mathrm{\α}}^2}}---\left(6\right)$

In formula (6), f _cfor first-harmonic centre frequency, unit is Hz; α is time scale, and unit is a second s.The discrete first-harmonic sequence that the mould of corresponding (6) is 1 is:

${\{A_k(f_c,\mathrm{\α})=\frac{1}{\sqrt{\sqrt{\mathrm{\π}}\mathrm{\α}{f}_s}}{e}^{2\mathrm{i\πk}{f}_c/f_s-\frac{k^2}{2{\mathrm{\α}}^2{f_s}^2}}\}}_{k\∈Z}---\left(7\right)$

In formula (7), f _sfor sample frequency, unit is Hz.The expression formula of the finite term of modus ponens (7) is:

${\{A_k(f_c,\mathrm{\α})=\frac{1}{\sqrt{\sqrt{\mathrm{\π}}\mathrm{\α}{f}_s}}{e}^{2\mathrm{i\πk}{f}_c/f_s-\frac{k^2}{2{\mathrm{\α}}^2{f_s}^2}}\}}_{k=-N}^N,(N/f_s\≥3\mathrm{\α})---\left(8\right)$

In formula (6) ~ formula (8), two basic parameter f of first-harmonic _cwith α be all the bound variable that has scope:

f _c∈[0,f _s/2]；α∈[α ₁，α ₂](9)

Can convert independent variable f above by arc tangent _cbecome independent variable u, the v on (∞ ,+∞) with the scope of α, have

$f_c=f_s(\frac{1}{4}+\frac{1}{2\mathrm{\π}}{\tan }^{-1}u);$ $\mathrm{\α}={\mathrm{\α}}_1+({\mathrm{\α}}_2-{\mathrm{\α}}_1)(\frac{1}{2}+\frac{1}{\mathrm{\π}}{\tan }^{-1}v)---\left(10\right)$

About (f _c, the variable that expression formula α) can be used in (u, v) that field of definition is (∞ ,+∞) represents:

A _k(f _c,α)=A _k(f _c(u),α(v))=B _k(u,v) (11)

Variation due to the field of definition of independent variable, can utilize Optimization without restriction to be optimized to u, v.

If with B _k(u, v) is first-harmonic column vector, [x _k] be complex signal section column vector to be matched, length is all 2N+1, and this signal segment to the projection P of first-harmonic is:

$P\left(\right[x_k\left]\right|\left[B_k(u,v)\right])=<\left[x_k\right],\left[B_k(u,v)\right]>={\left[B_k(u,v)\right]}^H\&CenterDot;\left[x_k\right]=\underset{k}{\mathrm{\&Sigma;}}{x}_k{B}_k{(u,v)}^{*}---\left(12\right)$

First-harmonic expression formula is (τ=α):

$G(t,\mathrm{\&tau;},f_c)=A*\exp (-\frac{t^2}{2*{\mathrm{\&tau;}}^2}+j*2*\mathrm{\&pi;}*f_c*t),-3*\mathrm{\&tau;}\&le;t\&le;3*\mathrm{\&tau;}---\left(13\right)$

Claims (2)

1. A method for positioning the top dead center of a six-cylinder engine, characterized in that: the method comprises the steps of: (1) Set the first measuring point between the first cylinder and the second cylinder of the six-cylinder engine, set the second measuring point between the second cylinder and the third cylinder, and set the third measuring point between the fourth cylinder and the fifth cylinder The fourth measuring point is set between the fifth cylinder and the sixth cylinder, and an acceleration vibration sensor is respectively installed on each measuring point, and the acceleration vibration sensor is connected to the computer through a vibration signal acquisition instrument; (2) Collect the acceleration vibration signals of the six working cylinders of the engine for no less than one working cycle, and obtain the vibration response time domain signals of the six working cylinders of the engine; (3) Perform Silbert transform on the vibration response time domain signals of the six working cylinders of the engine to obtain the complex signals of the six working cylinders of the engine; (4) Using the Gaussian wave correlation filter method to extract the complex signals of the six working cylinders of the engine to obtain the characteristic parameters of the combustion shock response of the six working cylinders of the engine; (5) Obtain the digital quantization matrix A between the measuring point and the six working cylinders of the engine according to the row order of the first measuring point, the second measuring point, the third measuring point and the fourth measuring point: matrix $A=\left[\begin{array}{cccccc}1.0& 0& 0.5& 0& 1.0& 0\\ 0.5& 0& 1.0& 0& 1.0& 0.5\\ 0& 1.0& 0.5& 0.5& 0& 1.0\\ 0& 1.0& 0& 1.0& 0& 0.5\end{array}\right]$ ⑹. Set the combustion shock response characteristic parameters of engine crankshaft angles of 0°, 120°, 240°, 360°, 480°, and 600° to XA, XB, XC, XD, XE, and XF respectively; ⑺. According to the column order of XA, XB, XC, XD, XE, XF, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix B; According to the column order of XB, XC, XD, XE, XF, XA, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix C; According to the column order of XC, XD, XE, XF, XA, XB, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix D; According to the column order of XD, XE, XF, XA, XB, XC, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix E; According to the column order of XE, XF, XA, XB, XC, XD, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix F; According to the column order of XF, XA, XB, XC, XD, XE, list the combustion shock response characteristic parameters corresponding to each measuring point of matrix A to form matrix G; ⑻. Multiply each value of matrix A and matrix B one by one and then sum to obtain S1; Multiply the values of matrix A and matrix C in one-to-one correspondence and then sum to obtain S2; Multiply the values of matrix A and matrix D in one-to-one correspondence and then sum to obtain S3; Multiply each value of matrix A and matrix E in one-to-one correspondence and then sum to obtain S4; Multiply each value of matrix A and matrix F in one-to-one correspondence and then sum to obtain S5; Multiply the values of matrix A and matrix G in one-to-one correspondence and then sum to obtain S6; ⑼. Take the one with the largest median among S1, S2, S3, S4, S5, and S6, and the engine working cylinder corresponding to XA among the ones with the largest value is the engine working cylinder corresponding to the top dead center. 2. The method for locating the top dead center of a six-cylinder engine according to claim 1, wherein the six-cylinder engine is a six-cylinder diesel engine or a six-cylinder gasoline engine.