CN103592065A - Method for detecting instantaneous output torque of diesel engine - Google Patents

Abstract

The invention discloses a method for detecting instantaneous output torque of a diesel engine, which is characterized by comprising the steps of detecting instantaneous three-phase phase voltage ua, ub, uc and three-phase phase current ia, ib, ic of a generator; calculating instantaneous output power Pe of the generator, wherein Pe=uaia+ubib+ucic; calculating instantaneous output power P of the diesel engine, wherein P=Pe/eta1; and calculating instantaneous torque T of the diesel engine, wherein T=9550*(P/N). According to the method disclosed by the invention, the instantaneous output power of the generator and the instantaneous torque of the diesel engine can be detected, thereby being capable of reflecting the current working states of the generator and the diesel engine more authentically and more accurately, and having very important significance for analyzing and controlling the operating states of the generator and the diesel engine.

Description

The instantaneous output torque of diesel engine detection method

Technical field

The present invention relates to the instantaneous output torque of a kind of diesel engine detection method, belong to Diesel Engine Technique Field.

Background technology

It is the important content that diesel engine performance index detects that diesel engine output torque detects, and conventionally utilizes dynamometer to realize, and exchanges dynamometer and be exactly common a kind of.Utilize and exchange the scheme that dynamometer carries out diesel engine output torque detection, conventionally have following two kinds.

Scheme one:

Gather the phase voltage effective value U of generator phase_p, phase current effective value I_pand the phase differential of phase voltage and phase current

and according to formula

the output power of calculating generator, and then calculate the output torque of diesel engine.

Scheme two:

Gather the line voltage effective value U of generator two-phase_i, phase current effective value I_pand the phase differential of phase voltage and electric currentand according to formula

the output power of calculating generator, and then calculate the output torque of diesel engine.

Owing to there is hysteresis problem, the phase differential of certain phase voltage and electric current in the voltage effective value of generator and the detection of current effective value

sense cycle identical with the cycle of generator output voltage, therefore all there is hysteresis problem in above-mentioned two detected generated output powers of scheme and diesel engine output torque, especially, when generator output frequency is low, hysteresis situation is even more serious.Therefore the instantaneous output that such scheme all can not actual response generator, thus can not actual response go out the instantaneous torque of diesel engine.

Summary of the invention

Object of the present invention overcomes the deficiency of above-mentioned prior art exactly, and the instantaneous output torque of a kind of diesel engine detection method is provided.

The object of the present invention is achieved like this: the instantaneous output torque of a kind of diesel engine detection method, is characterized in that taking the following step:

B. detect the wink three-phase phase voltage u of generator_a, u_b, u_cwith three-phase phase current i_a, i_b, i_c;

B. calculating generator instantaneous output$P_e=u_a{i}_a+u_b{i}_b+u_c{i}_c;$

C. calculate diesel engine instantaneous output

(wherein: η is efficiency of generator);

D. calculate diesel engine instantaneous torque

(wherein: N is diesel engine speed).

The solution of the present invention, can detect the instantaneous torque of instantaneous output and the diesel engine of generator, the work at present state that reflects more truly, accurately generator and diesel engine, is of great significance the analysis of generator and diesel engine running status, control tool.

Accompanying drawing explanation

Fig. 1 is generator three-phase alternating current phase voltage and phase current waveform.

Fig. 2 is the instantaneous phase voltage waveform of generator.

Fig. 3 is the instantaneous phase current waveform of generator

Fig. 4 is the generator instantaneous output waveform detecting with instantaneous phase voltage and instantaneous phase current.

Fig. 5 is the instantaneous output torque of the diesel engine of embodiment of the present invention detection method FB(flow block).

Embodiment

For making object, technical scheme and the advantage of the embodiment of the present invention clearer, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

Referring to Fig. 1, for threephase alternator, at U₁u₂, V₁v₂, W₁w₂on three phase windings, show that frequency is identical, amplitude equates, the sinusoidal phase voltage of three-phase symmetrical of 120 ° of phase place mutual deviations, they are respectively u_a, u_b, u_c, and with u_afor with reference to sinusoidal quantity:

After generator band carries (establishing threephase load symmetry), due to each phase load impedance equate (be each phase of impedance mould | Z| and phasing degree

equate), and each phase voltage is symmetrical, so load phase current i_a, i_b, i_calso symmetrical, and with i_afor with reference to sinusoidal quantity:

To any time t, detect the three-phase phase voltage u of this moment generator_a, u_b, u_cwith three-phase phase current i_a, i_b, i_c(as the intersection point of Fig. 1 dotted line and three-phase alternating current phase voltage and three-phase alternating current phase current), and according to P_e=u_ai_a+ u_bi_b+ u_ci_ccalculating generator instantaneous output.

After MATLAB emulation, can verify, getting as stated above at any time generator phase voltage and phase current, to calculate resulting generator instantaneous power be constant, is expressed as a straight line (as shown in Figure 2,3, 4) with transverse axis in figure line.

Referring to Fig. 5, the instantaneous output torque of the diesel engine of the present embodiment detection method, from frame 1.0.

Enter frame 1.1, to any time t, detect the three-phase phase voltage u of this moment generator_a, u_b, u_cwith three-phase phase current i_a, i_b, i_c.

Enter frame 1.2, and calculating generator instantaneous output:

P_e＝u_ai_a+u_bi_b+u_ci_c

Enter frame 1.3, calculating generator momentary efficiency:

${\mathrm{\&eta;}}_1=\frac{2(\sqrt{({\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}1}^2-\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}2*K3)}-K1)}{\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}2}$

Wherein:

$\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}1=1-\frac{2.8*\mathrm{QF}*N^{-0.7}}{I}$

$\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}2=\frac{4*\mathrm{QF}*N^{-0.7}*P_e}{{\mathrm{<figure-callout\; label="I"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">I</figure-callout>}}^2}$

$\mathrm{<figure-callout\; label="K"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">K</figure-callout>}3=\frac{{\mathrm{QC}*\mathrm{<figure-callout\; label="I"\; filenames="HDA0000392185420000012.png,HDA0000392185420000021.png"\; state="\{\{state\}\}">I</figure-callout>}}^2+1.96*\mathrm{QF}*N^{-0.7}+\mathrm{QM}}{P_e}-1$

QC＝5.370748086E-03

QF＝4.4866781369

QM＝0.0089332456*N^2.00276

N: diesel engine speed, rpm

P: generated output power, w

I: generator output current, A

Enter frame 1.4, calculate diesel engine instantaneous output P:

$P=\frac{P_e}{{\mathrm{\&eta;}}_1}$

Enter frame 1.5, calculate diesel engine instantaneous torque T:

$T=9550\frac{P}{N}$

Wherein: N is diesel engine speed.

Finally it should be noted that: above embodiment only, in order to technical scheme of the present invention to be described, is not intended to limit; Although the present invention is had been described in detail with reference to previous embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or part technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (1)

1. the instantaneous output torque of a diesel engine detection method, is characterized in that taking the following step:

A. detect the wink three-phase phase voltage u of generator_a, u_b, u_cwith three-phase phase current i_a, i_b, i_c;

B. calculating generator instantaneous output P_e=u_ai_a+ u_bi_b+ u_ci_c;

C. calculate diesel engine instantaneous output

(wherein: η is efficiency of generator);

D. calculate diesel engine instantaneous torque

(wherein: N is diesel engine speed).

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