SU817503A1 - Stand for testing internal combusion engine - Google Patents

Description

the second input of the second block is a lot of.

The drawing shows the proposed stand.

The device contains a load device, filled in the form of an asynchronous electric machine 1, connected to the shaft of the test engine 2 and the sensor 3 of the shaft rotation frequency,

In the rotor circuit of the electric machine 1 is included meter 4 of the rotor current. The output of the sensor 3 rotational speed is connected to the meter 5 mechanical losses and the first input of the first block

6 times higher. The second multiplication unit 7 is connected by the first input to the measuring 4 of the rotor current, and the output - in series with the output of the mechanical loss meter 5 is connected to the second input of the first multiplication unit 6 through the switch 8. The output of the multiplication unit 6 together with the recorder 9

A meter 10 of the direct and inverse symmetrical components of the supply voltage, containing three phase transformers 11-13, as well as the first 14 and second

15yp mites. The first output windings of transformers 11-13 are interconnected in an open triangle and connected to the first rectifier 14. -The second output windings of transformers 11-13 are interconnected

into a star and connected to the second rectifier 15, the output of which is connected in series and in accordance with the output of the first rectifier 14. Parallel to the outputs of rectifiers 14 and 15, the capacitors are smoothed.

16 and 17. The output of the meter 10 is connected to the second input of the second unit.

7 times higher.

The stand works as follows.

When testing an internal combustion engine or other unit (the electric machine operates in the generator mode), its torque is determined by the formula

NKR ", | p (and" p +) + m

(one)

MP

de K is a constant coefficient, 50 taking into account the transformation ratio of the electric machine and the synchronous frequency of rotation of the electric motor; its IP is the rotor current; and „p - right is symmetrical component of the supply voltage

networks;

 - reverse symmetric component of the mains voltage; MP - the moment of mechanical losses

in an electric car. The signals from the outputs of the meter 4 of the rotor and the meter 10 are received 65

to the inputs of block 7 multiply. Its output signal, proportional to the first term of formula (1), is added to the output signal of the mechanical loss meter 5, which is proportional to the second term of formula (1), i.e., the value of the mechanical loss moment of the electric machine.

The sum signal, proportional to the torque of the ICE under test, is the output of the bench. To determine the power of the internal combustion engine, a signal proportional to the torque is fed to the second input of the multiplication block b, to the first input of which the output signal of the rotational speed sensor 3 arrives. The signal from the output of the first multiplication block b is proportional to the test person's two.

When measuring the torque or power of turning the output shaft of an internal combustion engine or other unit, the polarity of the output signal of the mechanical loss meter 5 is reversed using the switch 8. In addition, the outputs of the rectifiers 14 and 15 of the forward and reverse symmetrical components of the meter 10 are switched so that its output signal is proportional to the difference between the direct and reverse symmetric components of the supply voltage

The meter 10 operates as follows.

From the output of the first output windings of transformers 11-13, connected in an open triangle, the voltage proportional to the expression

V, (A s)

(2)

Where 2 the transformation ratio of transformers 1113;

a is a turn operator; CD, Ug - complex values

phase voltage supply.

Uewx is equal to the inverse symmetrical component of the supply voltage, and the output voltage of the rectifier 14 is proportional to this component.

It is known that the voltage of the direct symmetrical component of the mains supply is proportional to the constant component of the rectified voltage of the mains supply. This voltage is removed from the output of the rectifier 15. Since the outputs of the rectifiers 14 and 15 are connected in series and according to, the total voltage is equal to the sum of the direct and inverse of the symmetrical to the voltage of the supply network and is the output voltage of the meter 10 This voltage is fed to the input of the second multiplication unit 7.

Claims (1)

Claim - A test bench for an internal combustion engine, comprising a load device, a rotational speed sensor, a mechanical loss meter, first and second multiplication units, a rotor current meter and a recorder, the load device being made in the form of an electric machine with a phase rotor and connected to an engine shaft also with a frequency sensor connected to a mechanical loss meter and the first input of the first multiplication unit, the rotor current meter is connected to the first input of the second multiplication unit, output to which is connected in series with the output of the mechanical loss meter and connected to the second input of the first multiplication unit connected to the recorder, distinguishing: in order to increase the accuracy of power measurement by taking into account the asymmetry of the supply voltage, the stand is additionally contains a meter for the sum of the forward and reverse symmetrical components of the voltage of the supply network, made in the form of three-phase voltage transformers and two rectifiers, the first rectifier connected to the first output ohm transformer branches connected to each other in an open triangle, and the second rectifier to the second output windings 26 connected to each other in a star, and the output of the second rectifier is connected. sequentially and in accordance with the output of the first rectifier and connected to the second input of the second multiplication block.