SU1104309A1 - Device for checking fuel injection - Google Patents

Abstract

A DEVICE FOR INSPECTION OF FUEL INJECTION to an internal combustion engine, comprising a sensor of the process under investigation, a band-pass filter of a carrier frequency, a low frequency amplifier, a signal analysis device, a time interval meter, a trigger circuit and an indicator, the amplifier being connected to an analyzer and one of the inputs meter, to another input of which the start-up circuit is connected, and to the output - an indicator, characterized in that, in order to increase accuracy, it additionally includes an ultrasonic frequency generator, an ultrasound azvukovoy transmitting sensor and the envelope detector and the test sensor is designed as a process of the ultrasonic receiver, the generator, i transmissive sensor and the receiver are connected in series at the input polo (LS cial filter associated through the detector to the input of the amplifier 4 with the;. of

Description

The invention relates to tests and diagnostics of fuel supply equipment of internal combustion engines, mainly diesel engines.

Known devices for monitoring 5 fuel injection, comprising a sensor of the process under study, a carrier-frequency bandpass filter, a low-frequency amplifier, a signal analysis device, a time interval meter, a trigger circuit and an indicator, the amplifier being connected to an analysis device and one of the meter’s inputs, to the other input of which a start-up circuit is connected, and to the 15th output - indicator 0J.

However, such a device does not allow sufficiently accurate control, for example, of the injection advance angle due to the presence of interference from 20 other vibration sources.

The purpose of the invention is to improve the accuracy of control of fuel equipment.

This object is achieved by the fact ₂₅ that the device further includes a generator of ultrasonic frequency, ultrasonic transmitting probe and the envelope detector, and the sensor of the test process is configured as an ultrasound receiver, with a generator, a transmitting sensor and the receiver are connected in series to a bandpass filter input, connected through the detector with amplifier input.

The drawing shows a diagram of pre- ³⁵ Laga device.

The device comprises an ultrasonic frequency generator 1 connected to an ultrasonic transmitting sensor 2,

DO sensor of the process under investigation, made in the form of an ultrasonic receiver 3, a band-pass filter 4 of the carrier frequency at the output of the receiver 3, an envelope detector 5 at the output of the filter 4, an amplifier 6 low'frequency, connected ⁴⁵ to the meter 7 time intervals to which the circuit is connected 8 start, indicator 9 and device 10 analysis of the acoustic signal.

The ultrasonic transmitting sensor ³⁰ and ultrasonic receiver 3 are mounted on the engine nozzle and are identical in design. As the trigger circuit 8, a top dead center sensor may be used. 55 The acoustic signal analysis device 10 may be, for example, operator head phones.

A device for controlling fuel injection operates as follows

The oscillations generated by the ultrasonic frequency generator 1 and emitted by the ultrasonic transmitting sensor 2 propagate in the nozzle, where, under the influence of the fuel pressure, the needle makes periodic movements from the closed position to the open. The movement of the needle imposes modulation on the carrier ultrasonic frequency, since the propagation conditions of ultrasonic vibrations from the transmitting sensor 2 to the ultrasonic receiver 3, i.e. when moving the needle, ultrasonic vibrations receive a different degree of attenuation (shadow effect) and envelop it in different ways (phase modulation), which leads to amplitude-phase modulation. Modulated ultrasonic vibrations enter the ultrasonic receiver 3, pass through a bandpass filter 4 of a carrier frequency having a passband of нес _ns ± A, where f _HGC is the carrier frequency and a is the modulation frequency, detected by the envelope detector 5, amplified by a low frequency amplifier 6, and fed to 7 time interval meter that allows you to measure the time (angle) from the moment the nozzle needle (fuel injection) operates until the piston is at top dead center, signaled by the start circuit 8 or by the upper gauge your points. On the indicator 9 and in the device 10 analysis of the acoustic signal there will be signals of operation of only one nozzle, the one to which the ultrasonic transmitting sensor 2 and the ultrasonic receiver 3 are attached.

In the known device there are signals from all kinematic pairs of the engine, which complicates the measurement process. 0 nozzle operation is judged by modulation of the carrier ultrasonic frequency. The carrier frequency may be in the range of 100-10 MHz. The band-pass filter easily separates the modulated oscillations of the ultrasonic frequency from the entire spectrum of the acoustic signals of the engine, which is in the band up to 20 kHz, thereby increasing the signal-to-noise ratio. In this regard, the measurement error will be much smaller than in a known device.

Claims (1)

DEVICE FOR MONITORING INJECTION OF FUEL into an internal combustion engine containing a sensor of the process under study, a carrier-frequency bandpass filter, a low-frequency amplifier, a signal analysis device, a time meter, a start-up circuit and an indicator, the amplifier being connected to the analysis device and one of the meter input, to the other input of which has a triggering circuit connected to, and an indicator is connected to the output, characterized in that, in order to increase accuracy, it also includes an ultrasonic frequency generator, ultrasound the second transmitting sensor and the envelope detector, and the sensor of the process under study is made in the form of an ultrasonic receiver, and the generator, the transmitting sensor and the receiver are switched on sequentially at the input of the bandpass filter connected through the detector to the input of the amplifier. SU ... 1104309 1 1104309