SU1467424A2 - Method of testing internal combustion engine - Google Patents

Abstract

The invention improves the accuracy of the tests. For this, the mathematical expectations of the efficiency of the automatic control and regulation systems (AISS) of the engine are specified in the form of random signals related to a mathematical model recorded by a multidimensional discrete-continuous Markov process and deviations from mathematical predictions in the form of random signals related to auto- and mutual correlation with the sonic functions with parameters obtained under the conditions of engine operation. Measurements of the effectiveness of the SAUR of the tested engine are measured and, according to the specified signals and measured performance indicators, the position of the adaptive organs of the SAUR is corrected. The parameters of the operational efficiency of the SAUR system are based on the accuracy of maintaining the set value of the engine crankshaft rotation frequency and the accuracy of maintaining the coolant temperature. The accuracy of the tests is increased by bringing the totality of all the operating modes of the engine under test to real operating conditions, 1 hp. f-ly, 1 il .. F

Description

one : .

The invention relates to the testing of internal combustion engines, in particular, to methods for setting the operating modes of the engines on a test bench, and is an improvement of the method according to ed. ISf 1147945.

The aim of the invention is to improve the accuracy of the tests.

The drawing shows a functional diagram of the device that implements the proposed method.

The device contains a test stand 1 consisting of a motor and a load element, control unit 2 associated with stand 1 and the first generator 3 of vector discrete-continuous Markov process signals, the output of which is connected to the input of the second generator 4 of random signals, computing unit 5 and the third generator 6 random time intervals of the engine operating modes 6.

The device works as follows.

Under the conditions of operation of internal combustion engines, a simultaneous recording is made.

ten

15

parameters of load mode and modes of automatic control and regulation systems (for example, automatic control system and control of engine speed, automatic control system and temperature control of water cooling): the moment of resistance on the motor shaft (M), the set value of engine rotation frequency ( ), setpoint temperature of the cooling water (t). The process of changing the performance indicators of the automatic control and regulation systems j is also recorded simultaneously, for example, the accuracy of maintaining (deviation from) the setpoint of rotational speed (G), the accuracy of support. cooling water temperature ((ft °). In this case, the parameters are taken in the form of signals in the corresponding sensors: resistance torque sensor, rotational frequency adjuster, temperature adjuster, efficiency indicator sensors. Thus, a device consisting of a reference element is used as an accuracy sensor, To the inputs of which are connected - .JQ the outputs of the setpoint and the sensor of the corresponding parameter.

Parameters are recorded for a period of time j sufficient to obtain statistically

called quasi-stationary sections). For each of these areas, the expected values of the parameters are determined.

 I

t „1- M, (t) dt,

b t;

t,

i - 1 n; (t) dt;

ABOUT

t;

 mr (

(one)

t

i, V U. (t) dt;

 about 1

 t- (t) dt,. 1l

D® ™ hi f ("

20

25

m

ha

rf4

- mathematical expectations of the parameters M, p, L1, t, rft, respectively j, the duration of the whole process;

the duration of the analyzed quasi-stationary section;

current time value. The duration of the T-each quasi-T T-t representative implementations of the random-diary segment is a random process of these parameters in a magnitude. Its distribution is exploited. In the resulting cases, the exponential or normalization assigns temporary terms to a local law. Auto and

engine operation in approximately established modes of operation (so

called quasi-stationary sections). For each of these areas, the expected values of the parameters are determined.

 I

t „1- M, (t) dt,

b t;

t,

i - 1 n; (t) dt;

ABOUT

t;

 mr (

(one)

t

i, V U. (t) dt;

 about 1

 t- (t) dt,. 1l

D® ™ hi f ("

Q

0

five

m

ha

rf4

- mathematical expectations of the parameters M, p, L1, t, rft, respectively j, the duration of the whole process;

the duration of the analyzed quasi-stationary section;

current time value. T-duration - each quasi-T T-t 40

mutual correlation functions of parameters in quasistationary regimes:

KM; GO

-: ;; ) - m.) (M, () -m.) dt,

  Vb (t) - m.) (N (t + C) - m,.) Dt

about

Trt

tnt - - .iXM.Ct) - i

 0

4fr

-, X () - m ,. ) (t () - m.o) dt,

i, - L D 1t;

T

rr i

-LT- (tMfc) - m ..) (M. (t + D) - m ..) dt;

.-tilt i M

T; ° C

TO

(fn

, (C) 1 (crn, (t) - nij.), (Cfn, (t + 0 - -,

(C)

t.d.

t, -t

 (rfn. (t) - m) (n, (t + t) - u) dt,

(2)

one ; -;

t. - () - (- m ,, 4,) dt,

 I 0

1 -T- r - - t.

 l

), to „; (:),

Kt; (O, K,; (O,

) - autocorrelating functions

M parameters

n, t, fn, R., v, ()),

RfTniwi mutually corrected - 15

functional functions;

V, P

- n and M, t and M,

rfn and n, t

respectively.

Calculate the matrix of transitional values for the expectation of the parameters M, n, t, L

(3)

where p .. is the probability of an event

worthwhile is that the parameter having a value of m; on the i-oM quasi-stationary segment, will take the value m: on the J-OM segment. With the help of calculated statistics, random changes in the parameters of the load mode and tuning modes of the automatic control and engine control systems under operating conditions, such as, for example, moment of resistance, set rotational speed, set cooling water temperature, accuracy of rotation frequency maintenance, and accuracy of cooling temperature maintenance water, represented as a sum of two random processes, characterized by the following mathematical models:

. vector discrete-continuous Markov process (Markov-type homogeneous chain of events with discrete states and continuous time)

m

m

m

m

about.

ti

with parameters n,

 (ft tl „„

vector continuous random

the process of changing the mode parameters around their expected values

0

five

0

five

0

35

40

d

50

55

k, (O, k, (c), R.,., (c), K, s, (T),,

Rt, (O, KdV; (O, R / n.nXO, K .. (C),

).

Before testing, the characteristics of the discrete-continuous Markov process ii are introduced into generator 3; tpia, nit "-, m, j., obtained on the basis of operating data, similarly, the characteristics KW, - (J;), K" DS) -, .COi Kt, (C) i Rtv () i are entered into generator A K, n; (),, M, (- r) i KdV.CO; Rrft fxo. The parameters of the law of distribution of the engine running time in various modes are entered into the generator 6 of random time intervals. In the computing unit 5, which is a serially executed computer, standard, statistical analysis, processing and planning programs for the active experiment are introduced.

When activated, control unit 2 issues a command to both the engine start and generator 3, which outputs signal S to control the load element and control signals h, and automatic control systems and engine speed control and cooling water temperature, respectively. The generator 3 outputs the signals b and c, arriving at the computing unit 5, and completing the tuning operation mode of the automatic control systems and controlling the engine rotation frequency and the cooling water temperature. The generator 3 also outputs a signal g to control the generator 4. Upon the command of g, generator 4 generates a signal p for controlling the load element and control signals 1, d for the systems / automatic control and controlling the engine speed and cooling water temperature. The signals s and p are algebraically stored and fed to the actuator, controlling the value of the moment of resistance, the signals h and 1, a and d are algebraically added and fed to the actuators of the frequency and temperature control systems of the automatic control and frequency control of the engine and the cooling water temperature, respectively.

The generator 4 forms the signals 1, f, entering the computing unit 5. The signals b and 1, c and f. At the input of the computational unit 5, they are algebraically added and are random processes whose statistical characteristics are similar to the statistical characteristics of the processes for changing the performance indicators j (for example, the accuracy of maintaining a given 3Ha4emiH) and controlling the rotation frequency and temperature of the cooling water, respectively. x skspluatahdan. During the engine test, the performance indicators are removed from the sensors of the performance indicators g and J, which are fed to the computing unit 5s where they are compared with the signals b + 1 and with ff 4 & 1 the computing unit 5 determines the static characteristics of the difference signals, performs experiments on planning an active experiment, producing a 1T test of reproducibility of experiments, conducting a regression analysis and determining the regression equation, checking the significance of the coefficients of the regression equation, checking the adequacy of the regression equation ™ s, optimize and determine the values of the adjustment parameters of the automatic control and regulation systems. Using the output signals t and k of the unit 5, through the actuators, set the position of the tuning organs of the a: JTomatic systems and adjust the rotational frequency and temperature of the cooling water in accordance with each experiment in planning the experiment. Unit 5 sets, with the help of output signals, the position of the tuning / organs such that the quality of operation of the automatic control and regulation systems of the engine on the stand most closely corresponds to the operating conditions. At random intervals T, generator 6 issues commands to generator 3, for which it generates new values

control actions s

0

five

0

five

0

five

9

five

but

with

lit II

h

, In accordance with the matrix of transient probabilities F. This changes the signal g controlling the generator 4. The generators 3, 4 and 6 automatically adjust if the statistical characteristics of the output signals deviate from the set values.

Thus, the proposed method of testing allows to bring the totality of all engine operating modes (load systems of automatic control and regulation and adjustment) during bench tests to actual operating conditions. Thus, it is possible to reduce the time needed to create new and upgraded engines.

Claims (2)

1. Test method for internal combustion engine according to auth.St. W 147945, distinguished by the fact that, in order to increase the test accuracy, the mathematical expectations are also set for the performance indicators of the automatic control and regulation of the engine in the form of random signals related to the mathematical model described by the multidimensional discrete-continuous Markov process, and deviations from mathematical expectations in the form of random signals associated with auto- and cross-correlation functions with parameters obtained under conditions of engine operation, measured The performance indicators of the automatic control and regulation systems of the engine under test are determined and, according to the set signals and the measured performance indicators, the positioning of the tuning organs of the automatic control and regulation systems is carried out. 2. Method of pop, 1, characterized in that the parameters of the efficiency of functioning of the automatic control and regulation systems use the accuracy of maintaining a given frequency of rotation of the engine crankshaft and the accuracy of maintaining the temperature of the coolant.