CN100468036C - Detection device and method for fault of engine fuel system - Google Patents

Abstract

A method for detecting fault of fuel oil system on engine includes utilizing rotation speed detection unit and vibration detection unit to collect rotation speed signal and vibration signal simultaneously then carrying out comparison and analysis on then, obtaining advance angle of fuel oil injection by comparing lead edge of pulse waveform on rotation speed with lead edge of vibration waveform on combustion and enabling to accurately judge out operation condition of air cylinder by analyzing magnitude value of vibration waveform.

Description

The pick-up unit of fault of engine fuel system and method

Technical field

The present invention relates to a kind of detection technique of engine failure, refer in particular to a kind of pick-up unit and method of fault of engine fuel system.

Background technology

The fuel system major failure of engine has that indivedual cylinders are flame-out, injection advance or fall behind etc.Flame-out main cause is that fuel injector stops up, injection pump charge oil pressure deficiency, makes fuel can not form good atomizing, thereby causes that respective cylinder do not work.Flame-out one side causes the very big waste of fuel, as for a machinery for the PZ12V190 engine, if there is a cylinder flame-out, then can cause the waste of nearly 1/12 fuel, therefore and nearly hundred million yuans of the fuel costs of loss according to incompletely statistics, domestic large-scale diesel engine; On the other hand, then cause engine power output not enough, influence is produced, and makes the moment of torsion imbalance of complete machine, causes torsional oscillation, influences the life-span of engine.Injection advance or backwardness then are because there is error in the adjustment of fuel supply advance angle, make fuel oil not supply with cylinder in the moment of regulation, thereby can cause that insufficient, the detonation of burning, row's temperature cross high phenomenon, also can reduce the power of engine and export, and the complete machine performance is caused harmful effect.

Therefore, have very big economic worth for the detection of above-mentioned fault, also significant to guaranteeing safety in production simultaneously.The detection method of fuel system mainly contains vibration method of purification, Waveform Analysis Method, Spectral Analysis Method and frequency response function method etc. at present, these methods have been diagnosed the faults such as flame-out, detonation of fuel system effectively from different angles, but can't judge the size of delivery angle, thereby has certain one-sidedness, cause explain failure cause ability a little less than, not strong to the directiveness of fixing a breakdown.

In view of this, the inventor is to be determined to be engaged in the experience that this area is researched and developed for many years, made with it for solving the problem that above-mentioned known technology exists, and obtains the present invention after development research repeatedly finally.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of pick-up unit and method of engine failure are provided, and it can detect the fuel supply advance angle of engine, and whether can judge combustor inner cylinder good, to reach the purpose of fuel system being carried out complete detection.

Technical solution of the present invention is: a kind of pick-up unit of fault of engine fuel system, it comprises rotation speed detection unit, vibration detecting unit and data processing unit, wherein, described data processing unit receives the combustion vibration signal of detected tach signal of described rotation speed detection unit and vibration detecting unit acquisition, and to above-mentioned signal amplify, mould/number conversion handles, the tacho-pulse waveform that comparative analysis obtains and combustion vibration waveform are with judgement fuel supply advance angle and combustion position.

The pick-up unit of aforesaid fault of engine fuel system, wherein, described rotation speed detection unit comprises the reflecting piece at the zero graduation place that is attached at engine flywheel and is arranged at the photoelectric sensor that top dead centre pointer place is used to accept described reflecting piece signal.

The pick-up unit of aforesaid fault of engine fuel system, wherein said vibration detecting unit comprises a vibration acceleration sensor, and this vibration acceleration sensor is arranged at the cylinder lid surface of engine to receive described vibration signal and to send this data processing unit to.

The pick-up unit of aforesaid fault of engine fuel system, wherein said pick-up unit also comprises a display unit, the analysis and judgement result of described data processing unit is sent to this display unit and shows.

The pick-up unit of aforesaid fault of engine fuel system, wherein said data processing unit have a pair of channel data collector, gather the tach signal of described rotation speed detection unit and the vibration signal of vibration detecting unit simultaneously.

The present invention also proposes a kind of detection method of fault of engine fuel system, and described detection method comprises: the tach signal of detection of engine and combustion vibration signal; Above-mentioned tach signal is handled, and comparative analysis the tacho-pulse waveform and the combustion vibration waveform that obtain, judge fuel supply advance angle and combustion position.

The detection method of aforesaid fault of engine fuel system, wherein the determining step of fuel supply advance angle comprises: A. calculates engine rotation period T and rotational speed N according to the position of continuous two pulses in the rotary speed data; B. calculate time t apart between pulse waveform forward position and the vibrational waveform forward position; C. obtain the actual measurement injection advance angle α under rotational speed N; D. a described actual measurement injection advance angle α and a standard injection advance angle α ' are compared, draw the injection advance situation of current cylinder: if α α ', injection advance; If α＜α ', oil spout falls behind.

The detection method of aforesaid fault of engine fuel system, wherein the determining step of above-mentioned combustion position comprises: A. calculates the effective value X of combustion vibration waveform _RmsB. with the effective value X of this combustion vibration waveform _RmsWith a standard effective value

Compare, to judge combustion position.

The detection method of aforesaid fault of engine fuel system wherein, also comprises and sets this standard effective value

Permission variation factor α, β, and the effective value X of described this combustion vibration waveform _RmsWith the standard effective value

Comparison step comprise: a) if α $X_{\mathrm{rms}}^{\&prime;}\&le;X_{\mathrm{rms}}\&le;{\mathrm{\&beta;}}^{X_{\mathrm{rms}}^{\&prime;}}$ , show that then burning is normal; B) if $X_{\mathrm{rms}}>{\mathrm{\&beta;}}^{X_{\mathrm{rms}}^{\&prime;}}$ , illustrate that the phenomenon of detonation exists; C) if $X_{\mathrm{rms}}<{\mathrm{\&alpha;}}^{X_{\mathrm{rms}}^{\&prime;}}$ , illustrate that flame-out phenomenon exists.

The detection method of aforesaid fault of engine fuel system, wherein: α=0.7, β=1.4.

Characteristics of the present invention and advantage are: the pick-up unit of engine failure of the present invention and method are provided with rotating speed, the vibration signal that rotation speed detection unit and vibration detecting unit are gathered engine simultaneously, and be analyzed, by the forward position of contrast tacho-pulse waveform and the forward position of combustion vibration waveform, can obtain the size of injection advance angle; By analyzing the amplitude of vibrational waveform, can accurately judge the working condition of cylinder, thereby overcome the defective of prior art, the situation that can reflect burning work all sidedly, and can point out the reason of fault, be a kind of to the big-block engine fuel system carry out fast, the accurate apparatus and method of assessment.Simultaneously, the present invention also can show detected result by display unit, further, also can come the correlation parameter of engine is carried out suitable adjustment in conjunction with known supervising device, makes it reach optimum combustion regime.

Description of drawings

Fig. 1 is the structured flowchart of the pick-up unit of engine failure of the present invention.

Fig. 2 is the structural representation of the pick-up unit of engine failure of the present invention.

Fig. 3 is a data analysis synoptic diagram of the present invention.

Fig. 4 is for judging the process flow diagram of injection advance angle in the detection method of engine failure of the present invention.

Fig. 5 is for judging the process flow diagram of combustion position in the detection method of engine failure of the present invention.

The drawing reference numeral explanation:

1, body 2, flywheel 3, index dial

4, vibration detecting unit 40, vibration acceleration sensor 5, rotation speed detection unit

51, photoelectric sensor 52, light tiles 6, data processing unit

Embodiment

Following conjunction with figs. and specific embodiment are described in further detail the specific embodiment of the present invention.

As shown in Figure 1, the pick-up unit of fault of engine fuel system of the present invention, comprise rotation speed detection unit 5, vibration detecting unit 4 and data processing unit 6, wherein, described data processing unit 6 receives the combustion vibration signal of described rotation speed detection unit 5 detected tach signals and vibration detecting unit 4 acquisitions, and by wherein amplifying circuit and A/D change-over circuit to above-mentioned signal amplify, mould/number conversion handles, comparative analysis tacho-pulse waveform and combustion vibration waveform are with judgement fuel supply advance angle and combustion position.

In conjunction with shown in Figure 2, described rotation speed detection unit 5 comprise the flywheel 2 that is attached at engine 1 index dial 3 the zero graduation place reflecting piece 52 and be arranged at the photoelectric sensor 51 that top dead centre pointer place is used to accept the signal of described reflecting piece 52.

Described vibration detecting unit 4 comprises a vibration acceleration sensor 40, and this vibration acceleration sensor 40 is arranged at the cylinder lid surface of engine to receive described vibration signal and to send this data processing unit 6 to.This vibration acceleration sensor can be piezoelectric acceleration transducer, is not limited in this certainly, also can be types such as magneto-electric, electric vortex type.

Described pick-up unit also comprises a display unit 7, and the analysis and judgement result of described data processing unit 6 can be sent to this display unit 7 and show.

In a specific embodiment kind of the present invention, described data processing unit 6 comprises an a pair of channel data collector and a computing machine, gathers this two kinds of signals simultaneously by the double channel data acquisition device, and carries out follow-up conversion, analyzing and processing and demonstration by computing machine.

During test, the photoelectric sensor 51 that is placed on top dead centre pointer place is aimed at reflecting piece 52 acquisition tach signals, and the vibration acceleration sensor 40 that places cylinder lid surface receives vibration signal, and be sent to data processing unit 6 through amplifying, comparing after the A/D conversion, to judge the injection advance angle and the combustion position of engine fuel oil system.Typical rotating speed-vibration double-channel signal is seen Fig. 3.

When reflecting piece 52 forwarded photoelectric sensor 51 places to diesel engine flywheel 2, photoelectric sensor 51 will receive a pulse signal, shown in the first half among Fig. 3.According to diesel engine work principle, at this moment the piston of the cylinder of surveying has also run to top dead centre, and like this, the position of pulse front edge is exactly the position of top dead centre, sees a point position among Fig. 3.And run to a certain angle of before upper dead canter at piston, fuel injector can be in cylinder oil spout and cause burning, produce vibration accordingly, shown in the latter half among Fig. 3, its oil spout can show from the forward position of combustion vibration waveform constantly, sees b point position among Fig. 3.

According to above-mentioned principle of work, below to describing in detail with the corresponding detection method of the pick-up unit of above-mentioned transmitter failure of fuel system.

This detection method is actual to be a rotating speed-vibration binary channels detection method, comprising: the tach signal of detection of engine and combustion vibration signal; Above-mentioned tach signal and vibration signal are handled, and resulting tacho-pulse waveform of comparative analysis and combustion vibration waveform, to judge fuel supply advance angle and combustion position.Two important steps below in conjunction with 4,5 pairs of detection methods of the present invention of accompanying drawing are elaborated:

One, in conjunction with shown in Figure 4, the determination methods of injection advance angle is as follows:

(1), calculate engine rotation period T and rotational speed N according to the position of continuous two pulses in the rotary speed data:

T＝MΔt (1)

$N=\frac{60}{T}---\left(2\right)$

M-engine rotation 1 is changeed the data number that is comprised in the formula, can draw by adding up two interpulse data numbers;

Δ t-sampling period, the i.e. inverse of frequency acquisition fc: Δ t=1/fc, generally get Δ t=5 * 10 ^-5S.

(2) calculate between pulse waveform forward position (a point among Fig. 3) and vibrational waveform forward position (the b point among Fig. 3) apart time t:

t＝mΔt (3)

Data number between m in the formula-pulse waveform forward position and vibrational waveform forward position.

(3) obtain actual measurement injection advance angle α under rotational speed N:

$\mathrm{\&alpha;}=\frac{360t}{T}---\left(4\right)$

(4) will survey injection advance angle α and standard injection advance angle α ' compares, and can draw the injection advance situation of current cylinder: if α α ', injection advance; If α＜α ', oil spout falls behind.

Two, in conjunction with shown in Figure 5, in rotating speed of the present invention-vibration binary channels detection method, it mainly is the effective value X according to the combustion vibration waveform _RmsCombustion position is judged.Determining step to combustion position is:

(1) the effective value X of calculating combustion vibration waveform _Rms, promptly

$X_{\mathrm{rms}}=\sqrt{\frac{1}{K}\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{x}_i}---\left(5\right)$

X in the formula _iThe time domain data of-combustion vibration waveform;

The number of K-data is gathered the length of file and is determined by real data, generally speaking, and K=30720.

(2) the standard effective value of supposing combustion vibration is

(can obtain by the engine of examination criteria state), measured value is X _Rms, set this standard effective value as required

Permission variation factor α, β, generally get α=0.7, β=1.4 compare the two then:

1. if $\mathrm{\&alpha;}{X}_{\mathrm{rms}}^{\&prime;}\&le;X_{\mathrm{rms}}\&le;\mathrm{\&beta;}{X}_{\mathrm{rms}}^{\&prime;}$ , measured value X even _Rms $0.7X_{\mathrm{rms}}^{\&prime;}~1.4X_{\mathrm{rms}}^{\&prime;}$ Between change, show that then burning is normal;

2. if $X_{\mathrm{rms}}>\mathrm{\&beta;}{X}_{\mathrm{rms}}^{\&prime;}$ , illustrate that the phenomenon of detonation exists;

3. if $X_{\mathrm{rms}}<\mathrm{\&alpha;}{X}_{\mathrm{rms}}^{\&prime;}$ , illustrate that flame-out phenomenon exists.

This invention utilizes the amplitude of engine, phase information to carry out analysis-by-synthesis, can reflect the situation of burning work all sidedly, and can point out the reason of fault, is a kind of apparatus and method that the big-block engine fuel system is carried out fast, accurately assessed.

Though the present invention has utilized aforementioned specific embodiment to disclose in detail, right its is not in order to limit the present invention, anyly have the knack of this skill person, without departing from the spirit and scope of the present invention, when doing various changes and modification, for example speed probe, vibration transducer also can use known other type sensor; Angle of advance that is obtained and combustion position also can provide to the foundation of control system as control, or the like, so protection scope of the present invention is as the criterion when looking claims person of defining.

Claims (10)

1. the pick-up unit of a fault of engine fuel system, it is characterized in that: this pick-up unit comprises rotation speed detection unit, vibration detecting unit and data processing unit, wherein, described data processing unit receives the combustion vibration signal of detected tach signal of described rotation speed detection unit and vibration detecting unit acquisition, and to above-mentioned signal amplify, mould/number conversion handles, the tacho-pulse waveform that comparative analysis obtains and combustion vibration waveform are with judgement fuel supply advance angle and combustion position.

2. the pick-up unit of fault of engine fuel system as claimed in claim 1, it is characterized in that: described rotation speed detection unit comprises the reflecting piece at the zero graduation place that is attached at the engine flywheel index dial and is arranged at the photoelectric sensor that top dead centre pointer place is used to accept described reflecting piece signal.

3. the pick-up unit of fault of engine fuel system as claimed in claim 1 or 2, it is characterized in that: described vibration detecting unit comprises a vibration acceleration sensor, and this vibration acceleration sensor is arranged at the cylinder lid surface of engine to receive described vibration signal and to send this data processing unit to.

4. the pick-up unit of fault of engine fuel system as claimed in claim 3, it is characterized in that: described pick-up unit also comprises a display unit, the analysis and judgement result of described data processing unit is sent to this display unit and shows.

5. the pick-up unit of fault of engine fuel system as claimed in claim 3, it is characterized in that: described data processing unit has a pair of channel data collector, gathers the tach signal of described rotation speed detection unit and the vibration signal of vibration detecting unit simultaneously.

6. the detection method of a fault of engine fuel system, described detection method comprises:

The tach signal of detection of engine and combustion vibration signal;

Above-mentioned tach signal is handled, and comparative analysis the tacho-pulse waveform and the combustion vibration waveform that obtain, judge fuel supply advance angle and combustion position.

7. the detection method of fault of engine fuel system as claimed in claim 6, it is characterized in that: wherein the determining step of fuel supply advance angle comprises:

A. according to the position of continuous two pulses in the rotary speed data, calculate engine rotation period T and rotational speed N;

B. calculate time t apart between pulse waveform forward position and the vibrational waveform forward position;

C. obtain the actual measurement injection advance angle α under rotational speed N;

D. a described actual measurement injection advance angle α and a standard injection advance angle α ' are compared, draw the injection advance situation of current cylinder: if α α ', injection advance; If α＜α ', oil spout falls behind.

8. as the detection method of claim 6 or 7 described fault of engine fuel system, it is characterized in that: the determining step of above-mentioned combustion position comprises:

A. calculate the effective value X of combustion vibration waveform _Rms

B. with the effective value X of this combustion vibration waveform _RmsWith a standard effective value

Compare, to judge combustion position.

9. the detection method of fault of engine fuel system as claimed in claim 8 is characterized in that: also comprise and set this standard effective value

Permission variation factor α, β, and the effective value X of described this combustion vibration waveform _RmsWith the standard effective value

Comparison step comprise:

A) if $\mathrm{\&alpha;}{X}_{\mathrm{rms}}^{\&prime;}\&le;X_{\mathrm{rms}}\&le;\mathrm{\&beta;}{X}_{\mathrm{rms}}^{\&prime;},$ Show that then burning is normal;

B) if $X_{\mathrm{rms}}>\mathrm{\&beta;}{X}_{\mathrm{rms}}^{\&prime;},$ Show that the phenomenon that detonation is arranged exists;

C) if $X_{\mathrm{rms}}<\mathrm{\&alpha;}{X}_{\mathrm{rms}}^{\&prime;},$ Showing has flame-out phenomenon to exist.

10. the detection method of fault of engine fuel system as claimed in claim 9 is characterized in that: α=0.7, β=1.4.

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