SU1474311A1 - Method of evaluating operability of fuel injection pump units - Google Patents

Abstract

The invention relates to engine-building and allows an increase in the reliability of the estimate. The magnitude of the geometric start of injection is determined, the phase of the dynamic start of fuel injection (DNNT) is determined by recording the vibration signal in the discharge line at the minimum stable and nominal rotational frequencies of the diesel engine and judging the section’s technical condition by comparison with the standard. The DNNT phase is determined at the nominal rotational speed over one of the pump sections, compared with the reference, and if necessary, the fuel injection pump is adjusted to obtain the desired angle DNNT. Then, the minimum value for each pump section is determined. rotation frequency of the diesel engine, at which the value of the angle DNNT is at least equal to the angle of the geometric start of injection, and by this min. rotational speed is judged on the technical condition of the section. Using the DNNT phase as an information parameter provides the ability to assess the technical state regardless of the density level of the plunger pair and the discharge valve. 3 il.

Description

one

The invention relates to engine building, and can be used to diagnose the technical condition of diesel fuel equipment.

The purpose of the invention is to increase the reliability by using as the information parameter the phase of the dynamic start of fuel supply, which makes it possible to assess the technical condition regardless of the density level of the plunger pair and the discharge valve.

FIG. 1 shows a block diagram of a device for implementing the proposed method; in fig. 2 - time diagrams of the device; in fig. 3 - dependence of the phase change of the dynamic start of injection on the frequency of rotation of a diesel engine of the type KAMAZ-740.

FIG. 2 denotes: a — the position marks of the flywheel from the driver and the angular marks of the period divider; b - vibration signals from the sensor of the beginning of the cycle; в - pulses from the output of the strobator; r - vibration start signals from the sensor; d - impulses corresponding to TDC diesel pistons; e is the measured angle of onset of injection.

The device (Fig. 1) contains a diesel engine 1 with a flywheel 2, nozzles 3, a fuel injection pump 4, fuel lines 5, a pressure start sensor 6, a vibration signal amplifier 7, a cycle start sensor 8, a cycle start generator 9, a scooper 10, an oscilloscope 11, the frequency meter 12, the sensor 13 of the position of the flywheel 2, the driver 14 of the mark of the position of the flywheel 2, the divider 15 of the period.

On diesel 1 with fuel injection pump 4, nozzles 3, fuel line

four

WITH

MI 5 (Fig. 1), the sensor 13 of the position of the flywheel 2, the sensor 8 of the start of the cycle, the sensor 6 of the start of injection, are installed. The sensor 8 start the cycle is connected to the first input of the shaper 9 start the cycle, the second input of which is connected to the output of the shaper 14. The first input of the strobator 10 is connected to the output of the shaper 9 the beginning of the cycle, the second input is connected to the output of the period divider 15, and its output is connected to the third input oscilloscope 11 (synchronization input). The frequency meter 12 is connected to the output of the sensor 13.

The beginning of the cycle of operation of the engine (cylinder) is taken when the piston passes through TDC at the beginning of the "Combustion. Consequently, a pulse corresponding to the position of the flywheel (TDC) must be taken at the beginning of the cycle, but since there are two such pulses in a four-stroke engine, we select the TDC pulse that is accompanied by a fuel injection pulse from sensor 8. Gating is performed using angle marks from the period divider 15 using a key, the closed and open state of which is determined by the number of corner marks from the moment the key is opened by the pulse of the beginning of the cycle.

The flywheel positioner 14 during crankshaft rotation generates square-shaped pulses from signals from sensor 13. Cycle-start driver 9 separates two TDC pulses from one sensor using pulse priority from sensor 8. Period divider 15 divides the revolution into 720 parts and forms rectangular corner marks and TDC marks for pistons.

The method for assessing the technical condition of the pump sections of the fuel-injecting pump 4 of diesel 1 (Fig. 1) consists in determining the magnitude of the geometric start of delivery, determining the phase of the dynamic start of fuel injection by recording the vibration signal in the discharge line at the minimum stable and nominal frequencies of rotation of the diesel and judge the technical condition of the section by comparison with the standard.

The phase of the dynamic start of fuel injection is determined by one of the sections of the pump 4, compared with the standard and, if necessary, the alignment of the fuel injection pump 4 is adjusted to obtain the desired angle of the dynamic start of delivery, then the minimum frequency is determined by each section of the pump 4. rotation of diesel 1, at which the value of the angle of the dynamic start of the fuel supply is at least equal to the angle of the geometric start of the fuel supply and at this minimum frequency of rotation Specify the technical condition of the section.

0 5

with

0 5

0

The method is carried out in the following sequence.

Sensors 6 and 8 are installed on diesel 1, respectively, the start of injection and the start of the cycle, as well as the sensor 13 of the position of the flywheel 2 (Fig. 1). The switch on the strobator 10 is set to the position corresponding to the diesel 1 cylinder to be tested (pump section 4). Diesel 1 is warmed up and the frequency of rotation of idling corresponding to the nominal value is set on the frequency meter 12 (or tachometer). In this case, the oscilloscope 11 indicates the vibrating signal from the start of discharge sensor 6, the TDC marks of the piston from the sensor 13 of the flywheel position 2 and the angular marks from the period divider 15 with an interval of 0.5 °. By the number of marks from the leading edge of the vibrating signal to the TDC reference mark, the angle (phase) of the start of injection is determined. The measured value of the phase of the beginning of the injection is compared with a reference value, tabular or graphical (Fig. 3). If a deviation from the standard is detected, it is eliminated by appropriate adjustment on the diesel. Next, the minimum rotational speed of the diesel is set and the phase of the start of injection is measured.

If the angle of the dynamic start of the fuel supply is less than the geometric angle of the start of the feed, then the diesel rotational speed is increased until the angle of the dynamic start of the feed becomes at least equal to the angle of the geometric start of the feed. The magnitude of the diesel rotational frequency at which this condition is met is used to characterize the technical condition of the pump section. After assessing the state of the pumping section, the start-up sensor 6 is moved to another section of the pump 4 and the measurements are repeated in the same sequence.

The method of assessing the technical condition of the pump sections provides an increase in the reliability of the estimate without increasing the labor intensity of the control, which is achieved by using the dynamic parameter of the fuel supply process, which allows an objective assessment of the state of even worn pump sections.

Claims (1)

Invention Formula The method for assessing the technical condition of the pump sections of the diesel fuel injection pump, which consists in determining the magnitude of the geometric start of injection, determines the phase of the dynamic start of fuel injection by recording the vibration signal in the discharge line at the minimum stable and nominal rotational frequencies of the diesel and evaluating the technical condition section on the result P30-28-26-2i422-20 "16 500 1000 1500 Ј000 2500 Fe.d. Editor L. Zaitseva Order 1863/30 Compiled by P. Pokrovsky Tehred I. VeresKorrektor V. Girn to Circulation 482 Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and publishing combine “Patent, Uzhgorod, ul. Gagarin, 101 Comparison with the standard, characterized in that, in order to increase the reliability, the phase of the dynamic start of fuel injection at the nominal rotational speed over one of the pump sections is determined, compared to the standard and, if necessary, the exposure of the fuel injection pump is adjusted to the required dynamic angle. start pumping 0 1 | III | || 111M | P | 11111 |||| 11ПиП || 11М1 ||| 1 1111 | П || 111 1М111М11 | П then, for each section of the pump, the minimum rotational frequency of the diesel engine is determined, at which the magnitude of the dynamic start of fuel injection is at least equal to the angle of the geometric start of fuel injection, and this section’s minimum rotational speed is judged on the technical condition of the section. 1