SU1280375A1 - Automated bed for testing internal combustion engine - Google Patents

Abstract

The invention relates to the field of testing of internal combustion engines and allows to simplify the design of the stand, to increase its reliability and efficiency. In the stand, the engine 2 is connected through an adjustable transmission, made, for example, in the form of an electric fume coupling, to a load device 3. Frequency sensors 5 and loads allow the operating mode to communicate through the load control unit 6 in one adjustable transmission. one . When pa. The engine is controlled by a control from the C block 6 transmission. 3 il. SS SC о © o 00 h3 Sd

Description

The invention relates to the mastinostroenio, in particular to the engine, in particular to stands for and testing of internal combustion engines.

The purpose of the invention is to simplify the design of the new reliability and efficiency of the stand.

FIG. Figure 1 shows a functional diagram of an automated test bench for an internal combustion engine, FIG. 2, a voltage timing diagram: a -, at the output of the pulse former; b at the output of the differentiating value; in the output of the integrator; g - at the output of the subtracting element; d - at the output of the comparator; Fig. 3 shows the dependence of the braking torque generated by the asynch1) one-way electric machine with a squirrel cage, on often; you rotate. .

The automated test bench for testing the internal combustion engine contains an adjustable gear 1 installed between the shaft of the engine under test 2 and the shaft of the electric load device 3, in the stator circuit of which the power measuring unit 4 is installed, the sensor 5 is the frequency of rotation. mounted on the shaft of the engine 2, and block 6, the load control connected by the first input to the output of the sensor 5, the second input to the output of the block 4, and the output to the controlled transmission 1,

The load control unit 6 comprises a subtractor element 7, a block 8 of reference voltages, a nonlinear converter 9, a serially connected 1-0 pulse generator, differentiating the CEG: AND, integrator 12, the output of the latter connected to the compiler 13, and the output of the comparator 13 through the key stage 14 and the high-pass filter 15 is connected to the output of the load control block b, the output of the nonlinear converter 9 and the output of the block 8 of the reference voltages are connected to the inputs of the subtracting element 7, and the output of the latter is connected to ertiruyuschim input of comparator 13, the input of the input 10 and the nonlinear transformer are input load adjustment unit 6.

Automated test bench, internal combustion engine - operates as follows.

When the stand is turned on, the engine 2 to be driven leads to. Turn the input shaft of the controlled transmission I and the rotational speed sensor 5. The load electric machine 3 is driven by the output shaft by an adjustable gear 1. The moment of force generated by the electric machine 3 has, as is well known, a non-linear dependence on the rotation frequency shown in FIG. 3. To adjust the load moment, an adjustable gear 1 is used, made, for example, in the form of a powder electromagnetic clutch. By changing its gear ratio, a change is made in the magnitude of the rotation frequency U on the shaft of the electric machine 3, which, according to the graph shown in FIG. 3, leads to a change in the load moment N on the shaft electromean-1-3.

The automatic adjustment and stabilization of the magnitude of the load moment is carried out by the load control unit 6. The signal from the output of the rotational frequency sensor 5, made, for example, in the form of a sinusoidal generator, arrives at the first input of the block b, this signal arrives at the input of the pulse shaper 10, which is a limiter of the voltage. The latter forms rectangular pulses at its output (Fig. 2ni). These pulses, having passed through the differentiating circuit 11, are converted into a sequence of short pulses (FIG. 2) synchronized with the pulses at the output of the pulse former 10, Sig comes from the output of the differentiating circuit 51 to the input of the integrator 12, which forms at its output a sequence of saw-tooth stresses (Fig. 2), synchronized to its input signal. The received signal goes to the non-inverted input of the comparator 13. Blocks 4, 7-9 are used to form a signal at the inverting input of the comparator 13, the load power measurement unit 4 generates a signal at its output proportional to the load power that goes through the non-linear converter 9 to the first the input of the subtracting element 7. The characteristic of the nonlinear converter 9 is chosen so as to linearize the nonlinearity of the characteristic of the electric machine 3 (FIG. 3) in the working area (from W to W). The presence of a nonlinear Transducer 9 leads to an increase in the accuracy of the load control, but its use is not necessary. The second input of the reading element 7 receives the reference voltage from the output of the block 8 of the reference voltages. The subtractive element 7 forms at its output a signal proportional to the difference of its own - input signals, which is fed to the inverting input of the comparator 13 (Fig. 22.) ,.

Comparator 13, depending on the difference of the signals at its inputs, forms a positive or negative signal with a standard amplitude at its output (Fig. 2 (j-)). The resulting signal is amplified by the current through the high-frequency cascade 14 and fed through a high-pass filter 15 to the control input. variable transmission 1. The upper frequency filter 15 provides an increase in voltage at the control input of the variable transmission I with an increase in the frequency of pulses at its input and, accordingly, with an increase in the frequency of rotation of the engine, which ensures There is no setting of the transmission ratio of the ground gear 1 so that the value of W falls in the middle of the working area of the electric machine 3 (FIG. 3) If, due to any one or two reasons, the load power decreases relative to the target, then the voltage at the outputs of the blocks 4, 9 , 7 and, respectively, at the inverting input of the comparator 13. This increases the part of the period during which the voltage at the non-inverting input of the comparator 3 is greater than at the inverting input. Therefore, the value of the constant signal of the signal output of the blocks 13-15 increases (Fig. 2 ()). This leads to an increase in the voltage on the control input of the regulated transmission 1 (Fig. 3), which leads to an increase in the load power and thus to stabilize it.

803754

Similarly, the processes occur with increasing moinost load. Thus, the implementation of the invention makes it possible to simplify the design, increase the reliability and efficiency of the stand by replacing the complicated in design, unreliable and low-cost electrophase with a phase rotor with an electromatin with a short locking rotor. In addition, due to the introduction of negative feedback on the load with the use of pulse-width modulation, the accuracy of load control increases.

/ 5 The use of the illumination modulation of the transmission control signal 1 minimizes the power loss of the control circuit operating in the key mode.

Claims (1)

Invention Formula Automated engine stand for engine internal combustion, containing an adjustable transmission, a load device in the form of an electric machine, a rotational speed sensor, a load sensor and a load control unit, made 30 in the form of a reference voltage block, a numeral element, a non-linear converter and a camcorder, the adjustable gear being placed between the motor shafts and the electric line and connected to the output of the load control comparator block, the output of the frequency sensor is connected to the input of the comparator of the load control block , and to the input of the non-converter40, connected via a computing element with a comparator, is connected the output of the load sensor, which is connected with the fact that, in order to simplify the design, the rigidity and efficiency of the stand, the load control unit additionally contains a pulse shaper, a differential circuit and an integrator included in series in connection with the frequency sensor with a comparator 5 as well as a high-pass filter and a key stage connected to the output of the comparator with an adjustable transmission, and the load sensor is designed as a power meter in the stator circuit of the electric mash of the load device. M  Otg fae. J