SU145807A1 - Tachometer device for measuring the speed of the shaft when testing the engine of internal combustion by the method of running out of revolutions - Google Patents

Description

The proposed tachometric device for measuring the shaft speed when testing engines of internal combustion by means of the stick out speed method allows, in contrast to the known devices of the same purpose, to increase the accuracy of determining the acceleration of the motor shaft during two consecutive turns.

This is achieved by using a highly stable timing controller in the device and two discrete electronic counters that are turned on by an electronic switch so that at the time of the first measured turnover, the time pulses go to one counter and the second turn to the second counter. The control unit and the electronic switch are connected to the pulse speed sensor in such a way that they automatically turn the electronic meters on and off.

The device is designed to measure the speed and acceleration of the shaft of internal combustion engines and to determine the speed of friction power at a known moment of inertia of moving parts or the moment of inertia of moving parts at a known power of friction using these data. The method of running out of revolutions is based on the principle of quenching by the forces of the kinetic energy of free rotation of the crankshaft of the engine.

Overrun is achieved by simultaneously turning off the ignition (or supplying fuel to the cylinders) and relieving the load from the engine.

FIG. 1 shows a block diagram of the device: FIG. 2-circuit of the pulse speed sensor.

No. 145807- 2 The device contains a pulse speed sensor / driven by a controlled motor shaft; highly stable time pulse generator 2; program switch 3; two discrete electronic counters 4 and 5; control unit 6; counter 7, counting two pulses.

The finger of the pulse speed sensor shaft 8 short-circuits the magnetic circuit of the horseshoe-shaped permanent magnet 9 with the self-induction coil 10 and the varying magnetic flux induces pulses in the coil. Formation of pulses ends when the shaft rotates at an angle of 1-2 °. When working with the device, the rubber tip of the sensor shaft // is pressed against the end of the ratchet of the engine shaft.

The highly stable time pulse generator 2 generates pointed pulses with an interval of 0.001 or 0.0001 ce / s / W (the higher frequency corresponds to multi-turn motors). Pulse generation accuracy at 0.1%. Amplitude of pulses 15 in.

The software switch 3 connects the time pulse generator to counter 4 with a signal from control unit 6 and from the third pulse voltage sensor of the speed sensor 1, turns off the counters from the fourth pulse speed sensor pulse to the counter 5, and from the fifth pulse. As a result, the counters will record the time intervals of the third and fourth revolutions of the engine shaft.

The speed, acceleration, power of friction and the moment of inertia of the duration of two subsequent shaft revolutions are determined by the number of time pulses recorded by the counters and by the corresponding formulas.

Pulse counters are manufactured using triggers on semiconductor transistors, as well as on electron tubes, decatrons and other counting elements, and are considered to be a binary system.

When using this device, it is necessary to skip the first two turns after turning off the ignition in order to ensure good repeatability of the experiment. During this time, all the physicochemical and mechanical phenomena inherent in the engine's transitional period (thickness, composition and temperature of the oil film on the cylinder mirror, change in the values of pressure in the cylinder and pumping losses, change in crankshaft angular velocity, etc.) disappear.

Subject invention

Claims (2)

1- Tachometer device for measuring the shaft speed when testing engines of internal combustion by means of a run-up speed method, containing a pulse speed sensor driven by a controlled shaft, a time pulse generator, an electronic switch, a control unit and electronic meters, characterized in that In order to improve the accuracy of determining the acceleration of the motor shaft for the period of two successive turns, a highly stable time pulse generator and two discrete electronic the counter, switched on by an electronic switch so that at the time of the first measured turnover the time pulses go to one counter, at the time of the second turn to the second counter. 2. In the device according to claim 1, the control unit and the electronic switch are connected to the impulse speed sensor so that they automatically turn on and off the electronic meters. Bbfuod Fig 2