RU2317438C1 - Device for measuring fuel deliveries of high-pressure fuel pumps - Google Patents

Abstract

FIELD: mechanical engineering; diesel engines.

SUBSTANCE: invention relates to testing of fuel equipment of internal combustion diesel engines and it can be used in adjustments of high-pressure fuel pumps of tractor and other diesel engines. Proposed device for measuring fuel deliveries of high-pressure fuel pumps contains nozzles with foam suppressors in number equal to number of pumping elements of pump under checking, fuel flow rate meter, computer with reading device and drain tubes. Fuel switch is installed between nozzles and fuel flow rate meter which is controlled by computer and provides alternate connection of fuel flow from nozzle under checking to fuel flow rate meter and draining of fuel from other nozzles. Device is finished additionally with unit to form stable fuel flow connected to input of fuel flow rate, meter, and fuel temperature transmitter connected at output of fuel flow rate meter and connected to computer. Computer is provided with additional input to connect camshaft speed meter of pump under checking.

EFFECT: increased capacity and improved accuracy of adjustment.

4 cl, 2 dwg

Description

The invention relates to the field of testing fuel equipment of internal combustion engines, in particular diesel fuel pumps, and can be used to modernize test adjusting stands.

Known devices for measuring the fuel supply, in which the pump performance is measured by the level of the beaker filling for a given number of plunger strokes, including glass measuring vessels with a scale [4].

The disadvantage of such devices is the need for visual reading of the measurement results from the scale of the measuring vessel and the lack of automation of the processing of measurement results.

Known devices for measuring the cyclic fuel supply [1, 2, 3, 5], in which the fuel is injected into a closed volume, part of the wall of which is the end face of a spring-loaded plunger, which moves when the fuel is supplied to this volume in proportion to the amount of supplied fuel, which is then fixed (in various ways) ) as a basis for calculating the amount of fuel supplied.

These devices are distinguished by the complexity of the design, the presence of precision elements, a complex pressure regulator [1], non-identical conditions for the next injection due to changes in the spring tightening [1], and the need for each section of its sensor.

Known devices for measuring the cyclic fuel supply, based on the integration of a signal proportional to the pressure of the fuel measured in front of the nozzle during the period of its injection with various preliminary corrections [6].

A disadvantage should be considered the subjectivity of the assessment and installation of the signal level, proportional to any parameter of the functioning of the diesel engine, set before measurements, the need for each section of its device.

A well-known stand for hydraulic testing of products, containing a series-connected flow tank with liquid, a pump, a discharge valve, measuring instruments and a pressure and drain line with nozzles for connecting test products, in which a tank is installed to provide testing of valves configured for different pressure partitions to sections communicated at the bottom, sensors of the upper and lower levels, filling and draining valves of the tank, as well as a switching unit that connects the level sensors to the valve filling and draining [7].

The disadvantage is the use of an additional tank, which increases the dimensions and weight of the stand, and the control of the switching unit by the filling and discharge valve only by the signals of the level sensors does not provide automatic testing of several valves.

As the closest prototype, a device for regulating high-pressure plunger fuel pumps [8] was adopted, comprising a fuel manifold, a high-pressure plunger fuel pump, an antifoam nozzle, a fuel consumption sensor equipped with a computing device and a display device, a drain pipe and a fuel tank .

The disadvantage of this device is the need for manual switching to each section of the pump in multi-cylinder engines, which significantly increases the time of adjustment work.

In addition, flow sensors of a mechanical type (with a rotating rotor) have an unstable (non-linear) characteristic at low flow rates, which reduces the accuracy of measuring and determining the moments of the beginning and end of fuel supply.

In addition, the physical parameters of the fuel and, accordingly, the readings of the flow sensor depend on temperature, which reduces the accuracy of the measurements.

According to the technical requirements for testing fuel pumps, the fuel temperature should be 35 ± 2 ° C [9].

In addition, this device actually measures the hourly capacity of the fuel pump, while regulation is required to be carried out according to the cyclic fuel supply specified in the passport for this pump, which increases the time of adjustment work.

The objective of the invention is to improve the accuracy and level of automation of the process of measuring fuel supply in the diagnosis and regulation of multi-section high-pressure fuel pumps.

The problem is solved due to the fact that the device for measuring the flow of high pressure fuel pumps, consisting of nozzles with defoamers by the number of sections of the pump being tested, a fuel consumption sensor, a computing device with a indicating device, drain pipes, is additionally equipped with a fuel switch connected between the nozzles and fuel consumption sensor, which is controlled by a computing device.

Also, the device can be additionally equipped with a stable fuel flow forming unit connected to the input of the flow sensor.

Also, the device can be additionally equipped with a fuel temperature sensor connected between the flow sensor and the drain pipe, the signals from which are fed to the computing device.

In addition, the computing device may have an additional input for connecting an external cam speed sensor of the pump under test.

Brief Description of the Drawings

Figure 1 presents a diagram of a device for measuring the flow of high pressure fuel pumps. Figure 2 presents the connection diagram of the device when measuring the cyclic supply of a 4-section high-pressure fuel pump on a test bench. The device consists of nozzles 1 with defoamers 2 according to the number of sections of the pump under test, fuel consumption sensor 3, computing device 4 with indicating device 5, drain pipes 6 and 7, fuel switch 8, stable fuel flow formation unit 9, fuel temperature sensor 10. Computational the device has an additional input for connecting a speed sensor of the cam shaft 14 of the pump under test.

The principle of operation of the device

Diesel fuel from the tank 12 is supplied by a fuel priming pump 11 to a 4-section high pressure fuel pump 13 mounted on a test bench. When the cam shaft of the pump is rotated, fuel under high pressure enters the corresponding nozzles 1 with defoamer 2 and then, already under low pressure, into the fuel switch 8. At the signal of the computing device 4, the fuel switch 8 directs fuel from the 1st nozzle to the fuel consumption sensor 3 and from the remaining nozzles through the drain pipe 6 directly to the tank 12. The fuel measured by the flow sensor 3 from the 1st nozzle through the pipe 7 also merges into the tank 12.

Computing device 4 processes the signals from the flow sensor 3 for the 1st section of the pump and outputs the measurement results to the indicating device 5. Next, the computing device 4 through the fuel switch 8 connects the next nozzle to the fuel consumption sensor 3, and the remaining nozzles to drain the fuel into the tank 12 through the tube 6, and the measurement process is repeated.

To improve the accuracy of the flow measurement, the fuel from the fuel priming pump 11 through the stable flow formation unit 9 is supplied to the fuel flow sensor 3 and then drained through the tube 7 into the tank 12. A constant fuel flow through the flow sensor 3 provides a shift of the operating point of the flow measurement to the linear region of the characteristic sensor. The computing device determines the actual performance of the measured section of the pump as the difference between the measured value and the constant flow of fuel. In order to improve the accuracy of measurement, the computing device 4 corrects the obtained value according to the signal of the fuel temperature sensor 10, located immediately after the flow sensor 3 and in front of the drain pipe 7.

In order to automatically measure the cyclic fuel supply to the computing device 4, an additional signal is supplied from the speed sensor of the cam shaft of the pump under test. The computing device calculates the cyclic flow of the fuel pump section as the ratio of the volume of fuel measured by the flow sensor 3 during the measurement to the number of perfect shaft revolutions (i.e. work cycles), which allows you to bring the measurement results to standardized values indicated in the documentation for fuel regulation high pressure pumps.

Thus, the use of a fuel switch in a device for measuring the fuel supply of a fuel allows automating the process of taking pump characteristics and, accordingly, accelerates adjustment operations, a stable flow formation unit and a fuel temperature sensor increase the accuracy of measuring the fuel pump performance, an additional input of a computing device for connecting a test speed sensor The stand allows you to automatically measure the cyclic feed sections of the fuel pump.

Information sources

1. Device for measuring cyclic fuel supply. RF patent No. 2059870, publ. 05/10/1996

2. Device for measuring cyclic fuel supply. RF patent №2116497, publ. July 27, 1998

3. A device for measuring uneven fuel supply. RF patent №2245453, publ. 01/27/2005

4. A device for measuring the fuel supply of fuel injection systems. RF patent №2162544, publ. 01/27/2001

5. Device for measuring the cyclic feeds of the fuel pump. RF patent №2253034, publ. 08/10/2004

6. A device for measuring the cyclic supply of fuel to an internal combustion engine. RF patent №2249806, publ. 04/10/2005

7. Stand for hydraulic testing of products. USSR copyright certificate, patent SU 1632145, publ. 04/20/2000

8. Device for regulating high pressure plunger fuel pumps. RF patent No. 2233993, publ. 08/10/2004

9. High pressure fuel pumps for automotive diesel engines. Test methods and regulation. RTM 10.457100-0001-01. M., GOSNITI, 2001

Claims (4)

1. A device for measuring the supply of high pressure fuel pumps, consisting of nozzles with defoamers in the number of sections of the pump being tested, a fuel consumption sensor, a computing device with a showing device, drain pipes, characterized in that it is additionally equipped with a fuel switch connected between the nozzles and the flow sensor fuel controlled by a computing device. 2. The device for measuring the flow of high pressure fuel pumps according to claim 1, characterized in that it is further provided with a stable fuel flow generating unit connected to the input of the flow sensor. 3. The device for measuring the supply of high pressure fuel pumps according to claim 1, characterized in that it is additionally equipped with a fuel temperature sensor connected between the flow sensor and the drain pipe, the signals from which are supplied to the computing device. 4. The device for measuring the supply of high pressure fuel pumps according to claim 1, characterized in that the computing device has an additional input for connecting an external cam speed sensor of the pump under test.

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