Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F3/00—Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow
  • G01F3/02—Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow with measuring chambers which expand or contract during measurement
  • G01F3/04—Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow with measuring chambers which expand or contract during measurement having rigid movable walls
  • G01F3/14—Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow with measuring chambers which expand or contract during measurement having rigid movable walls comprising reciprocating pistons, e.g. reciprocating in a rotating body
  • G01F3/16—Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow with measuring chambers which expand or contract during measurement having rigid movable walls comprising reciprocating pistons, e.g. reciprocating in a rotating body in stationary cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
  • F02M65/001—Measuring fuel delivery of a fuel injector

Definitions

• the present invention relates to a device for analyzing the blow-by-blow injection rate provided by a fuel injection system used in a heat engine.
• the injection systems concerned are notably those fitted to diesel engines.
• the invention described here applies, more particularly, to injection systems used in high-power engines, and therefore injection systems with a high fuel flow rate.
• Measuring devices are already known to enable injection and thermal engine manufacturers to carry out the development of the injectors as well as the adjustments and verifications of conformity during manufacture and during the installation of these systems for their end use. These measuring devices are used in conjunction with a specific test bench, whose role is mainly to drive an injection pump in rotation and to support the various elements of the injection system under test. Measurements made with these types of devices must make it possible to know both precisely the values of injected fuel volumes and the times or angles of injection.
• the device evoked here comprises a first measurement chamber which is a chamber of constant volume into which the fuel is injected, a chamber to which a pressure sensor and a temperature sensor are associated which respectively measure the pressure and the temperature prevailing in the chamber. this chamber, and means for draining at least partially said first measuring chamber.
• This device also comprises, downstream of the first measuring chamber, a second measurement chamber into which the fuel drained from the first measurement chamber is sent, the volume of the second measuring chamber being variable according to the movement of a piston whose displacement is measured using a displacement sensor.
• An electronic section controls the entire device, said section also analyzing the information received from the different sensors.
• the operating principle of this device is as follows:
• an injection is performed. This causes an increase in the pressure in the first measuring chamber, related to the amount of fuel injected, fuel characteristics, environmental conditions including the temperature and the initial pressure, and the volume of the chamber.
• the fuel contained in the first measuring chamber is partially emptied into the second measuring chamber, the pressure in the first measuring chamber thus being brought back to its initial target value and this first chamber being ready. then to receive a new injection.
• the fuel that arrives in the second measuring chamber increases the volume of the second measuring chamber by pushing the piston.
• the displacement of the piston is measured and, knowing the diameter of the piston, part of the electronic section calculates the exact volume of the fuel. This second measurement allows the electronic section to calibrate, at any time and exactly, the measurements that are made by the first measurement chamber.
• a fast solenoid valve controlled by a portion of the electronic section, and an overflow are arranged between the two measuring chambers to partially empty the first measuring chamber after an injection to find in this first measuring chamber the pressure that reigned in it before the injection in question.
• the electronic section advantageously further comprises a compensation function, allowing to take into account a possible difference in pressure in the first measuring chamber after two successive emptying.
• fuel here used to describe the fluid used in the device, in particular the fluid filling the two measuring chambers and also the injected fluid, denotes a real fuel or, preferably, a fluid which has hydraulic characteristics close to those of a fuel but with a flash point temperature much higher than that of a fuel, to minimize the risk of fire and explosion.
• first measurement chamber of constant volume makes it possible to accurately supply the "shape" of the injection
• second measurement chamber, of variable volume makes it possible to measure the quantity of fuel injected.
• the processing carried out in the electronic section makes it possible to compensate the defects of each of the measurements by the qualities of the other.
• the existing device is more particularly suitable for injectors that deliver a low or average amount of fuel, typically up to 100 liters per hour.
• the first measuring chamber which is of constant volume and serves to make an instantaneous measurement of the pressure increase during the injection in this volume already filled with fluid, there is no technical difficulty in simply increasing the dimensions to adapt to a larger flow.
• a volume typically less than one liter specific to previous embodiments, it is easy to provide a volume of greater value, adapted to the injection pump and / or the injector that is under test.
• the value of this volume is to be determined so as to obtain a typical increase in the pressure of a few bars or tens of bars, in the first measuring chamber, during a single injection, which leads to a typical volume of a few liters or tens of liters for this room, without these values being limiting.
• the piston must slide perfectly, without blocking or leakage, in the cylinder which defines the measuring chamber, while the overall temperature of this chamber is generally kept relatively low, typically between 40 and 70 ° C, but that the instantaneous temperature at the nose of the injector is high and can exceed 200 ° C for modern injection systems at very high pressure, typically greater than 2000 bar.
• the piston must be as light as possible in order to react rapidly to the volume changes resulting from the emptying of fuel in the measuring chamber, which leads to the realization of the piston with a hollow conformation and with a very small wall thickness .
• the assembly consisting of the cylinder defining the measuring chamber, and the piston slidably mounted in this cylinder, however must be very robust to withstand without damage many cycles of fuel injection, so filling / emptying of this measuring chamber with displacement of the piston.
• Pistons having a diameter of between 10 and 35 millimeters and which describe a travel of between 1 and 10 millimeters, which corresponds to a unit volume of measurement of between approximately 80 and 10,000 mm 3, are usually produced.
• the present invention aims to avoid these difficulties, and is therefore intended to provide a solution of the kind considered here but adapted to large injection rates, typically greater than 100 liters per minute, while remaining economical.
• the subject of the invention is a device for analyzing the blow-by-blow injection rate delivered by a fuel injection system used in a heat engine, the device comprising, in a known manner:
• a first constant volume measuring chamber into which the fuel is injected, a pressure sensor and a temperature sensor being associated with this first measuring chamber for respectively measuring the pressure and the temperature prevailing in said first measuring chamber,
• a second measuring chamber into which the fuel drained out of the first measuring chamber is sent, the volume of the second measuring chamber being variable according to the movement of a piston whose displacement is measured using a displacement sensor,
• an electronic section controlling the device and analyzing the information received from the sensors, so that the partial emptying of the first measurement chamber after injection is made until in this first measurement chamber the pressure prevailing therein is found again; injection, the device being, according to the invention, essentially characterized by the fact that at least one additional measuring chamber, whose volume is variable according to the movement of a piston whose displacement is measured with the aid of a displacement sensor, is mounted downstream of the first measuring chamber, in parallel with the second measuring chamber, so that the fuel drained out of the first measuring chamber is received in the second measuring chamber and / or in the or each additional measuring chamber, the electronic section being provided for measuring and adding the volumes received, for each injection, by the second measurement chamber and by the additional measurement chamber or chambers, so as to obtain a total volume corresponding to the quantity of fuel delivered for an injection stroke.
• the inventive idea consists in providing two or more measuring chambers of variable volume, mounted in parallel, in place of a single second variable volume measuring chamber.
• the total volume of fuel, drained out of the first measuring chamber can therefore be divided into two or more other measuring chambers, each of which receives and measures, by the movement of its piston, a partial volume; the addition of all the measured partial volumes provides the total volume injected at each stroke.
• the electronic section is designed to synchronously control the emptying of the first measuring chamber in the second measuring chamber and in the additional measuring chamber or chambers, in other words all measuring chambers of variable volume. Transfers of fuel to all these measurement chambers are therefore simultaneous, as well as partial volume measurements, the sum of which corresponds to the total volume for an injection shot.
• This embodiment has the advantage of its simplicity, from the point of view of controlling the device.
• the electronic section is provided for separately and in particular sequentially controlling the emptying of the first measuring chamber in the second measuring chamber and in the further measuring chamber or chambers. in other words, in the different measuring chambers of variable volume.
• This other control mode somewhat complicates the control of the device, each variable volume chamber to be controlled separately; however, it has the advantage of regulating the outflow of the first measuring chamber, some of the variable volume measuring chambers receiving fluid while others are already being drained.
• the second measuring chamber and the one or more measuring chambers are all identical and, in particular, of the same maximum capacity and of the same section which also corresponds to the section of the piston.
• the measuring chamber of larger capacity and in particular of larger section has a rather limited absolute accuracy of measurement
• the measurement chamber of smaller capacity and in particular of smaller section has a high accuracy. absolute measurement.
• the device has a high absolute measurement accuracy when the amount injected is small, while maintaining the ability to measure large quantities injected.
• the device therefore tends to provide a measurement whose relative accuracy remains substantially constant, which is a desirable advantage for any device or measurement device with a large measurement dynamic, that is to say for accurately measuring as well. small quantities than large quantities. In the present case, it is possible to measure very accurately, that is to say with an absolute precision of the order of one-thousandth of the maximum scale, injected quantities of between 100 mm 3 and 100,000 mm 3 per stroke. 'injection.
• the device of the invention not only makes it possible to measure higher injection rates than a single-chamber device of variable volume, but it also makes it possible to measure injection rates for higher injection frequencies, in proportion to the number of implanted measuring chambers.
• the configuration according to the invention is very advantageous because, by a simple adaptation of the parameters of the control software, it becomes possible to measure higher flow rates at higher injection frequencies, without constructive modification of the device.
• This single figure represents an injector 1, the injection nozzle 2 of which is in a first measuring chamber 3, which is a chamber of constant volume.
• the first measuring chamber 3 is, in use, filled with a fluid which has hydraulic characteristics similar to those of a fuel, but which has a flashpoint temperature much higher than that of a fuel, so to minimize the risk of fire and explosion.
• This fluid is also the fluid that is used in the injector 1.
• a reservoir 4 of this fluid is provided in the device.
• the first measuring chamber 3 advantageously comprises, as a pressure sensor, a dynamic pressure converter 5a and a static pressure converter 5b.
• the dynamic pressure converter 5a feasible in the form of a piezoelectric converter, is responsible for measuring the dynamic component for which a high resolution is sought - typically 0.001 bar - and a fast response.
• the static pressure converter 5b which can be produced in the form of a piezoresistive converter, is responsible for measuring the static component for which essentially a large dynamic range is sought, typically from 1 to 250 bars.
• the first measurement chamber 3 is also equipped with a temperature sensor 6, fast response.
• the first measuring chamber 3 has an outlet 7 which is directed towards a second measuring chamber 8, thus located (with reference to the direction of flow of the fluid) downstream of the first measuring chamber 3.
• a solenoid valve 9 is disposed between the first measuring chamber 3 and the second measuring chamber 8.
• the second measurement chamber 8 is a chamber of variable volume. It is made as a cylinder 10 in which is slidably mounted a piston 11, subjected to the thrust of a spring 12. The displacement of the piston 1 1 is detected by a displacement sensor 13, for example made in the form of a Inductive sensor. A temperature converter 14 is further associated with the second measuring chamber 8.
• Each additional measuring chamber 8a, 8b, ... 8n is also a chamber of variable volume, made as a cylinder 10a, 10b, ... 10n in which is slidably mounted a piston 11a, 11b, ... 11n, whose displacement is detected by a displacement sensor 13a, 13b, ... 13n.
• a solenoid valve 9a, 9b, ... 9n On each of these circuit branches, between the outlet 7 of the first measuring chamber 3 and the additional measuring chamber 8a, 8b, ... 8n corresponding, is arranged a solenoid valve 9a, 9b, ... 9n.
• the respective drain channels 15a, 15b, ... 15n of all the circuit branches each comprise a drain solenoid valve 16a, 16b, ... 16n, and these drain channels 15a, 15b, ... 15n meet between them and the drain channel 15 to bring the fluid back to the tank 4.
• the device also comprises, in a manner not shown, an electronic section which controls the entire device and analyzes the information received from the different sensors.
• the electronic section which controls the entire device and analyzes the information received from the different sensors.
• the electronic section :
• the solenoid valves 9, 9a, 9b, 9n are controlled to direct the fluid coming from the outlet 7 of the first measuring chamber 3 towards one or the other of the other measuring chambers 8, 8a, 8b, ... 8n; - Control the drain solenoid valves 16, 16a, 16b, ... 16n associated with these other measuring chambers 8, 8a, 8b, ... 8n to drain and return the fluid to the tank 4;
• the injector 1 carries out, through its nozzle 2, a fluid injection in the first measuring chamber 3. Thanks to the converters 5a and 5b, the pressure is measured and in particular the pressure in the first measuring chamber 3 is increased. , which makes it possible to determine the curve of the injected fluid flow as a function of time, possibly making a correction as a function of the temperature detected by the sensor 6. When the pressure in this first measuring chamber 3 no longer increases, deduce that the injection is complete.
• the solenoid valves 9, 9a, 9b, ... 9n are then opened, either synchronously or separately and in particular sequentially, to transfer the fluid from the first measurement chamber 3 to the other measurement chambers 8, 8a, 8b, ... 8n.
• the volume of these measuring chambers 8, 8a, 8b, ... 8n therefore increases, which is accompanied by a displacement of the corresponding pistons 11, 11a, 11b, ... 11n.
• the displacement sensors 13, 13a, 13b,... 13n measure the respective displacements of the pistons 1 1, 11 a, 11 b, ... 11 n.
• Each movement of a piston 11, 11a, 11b, ... 11n corresponds to a volume variation of the measuring chamber 8, 8a, 8b, ... 8n corresponding.
• the electronic section determines this variation in volume, by correcting it according to the signal supplied by the temperature sensors, such as the converter 14.
• the electronic section adds the partial volumes of fluid determined for the different measuring chambers 8, 8a, 8b, ... 8n, so as to obtain a total volume, which corresponds to the quantity of fluid which has been injected into the first measuring chamber 3.
• the electronic section also controls the different solenoid valves 16, 16a, 16b, ... 16n to bring the fluid into the tank 4 and to allow the return of the pistons 11, 11a, 11b, ... 11 n in their position initial, while the pressure in the first measuring chamber 3 returns to its initial set value. A new injection can then take place in this first measurement chamber 3, and so on ...
• the device can operate either using all measuring chambers 8, 8a, 8b, ... 8n of variable volume, or only some of these measuring chambers.
• the temperature can be measured and taken into account in various other places, in particular just upstream of the first measurement chamber 3, by an additional temperature sensor 18, to appreciate the rapid temperature variations of the injected fluid. before it is mixed and therefore equalized in temperature with the large amount of fluid already contained in this first chamber 3. It is not departing from the scope of the invention:
• these measuring chambers instead of being all identical, have different capacities from each other, with at least one measuring chamber of greater capacity and at least one measuring chamber of smaller capacity;
• variable volume measuring chambers by providing for a somewhat different operation, in particular with, for one or more of the variable volume measurement chambers, two or more partial filling / emptying cycles for measuring the quantity of fuel injected at each injection stroke, and with the addition of the partial volume measurements thus made, which makes it possible to adapt the device to even higher injection rates, without increasing the size of the device at the level of the variable volume measuring chambers.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Measuring Volume Flow (AREA)

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• 2008
  • 2008-09-05 FR FR0804885A patent/FR2935758B1/fr not_active Expired - Fee Related
• 2009
  • 2009-07-21 CN CN2009801345247A patent/CN102144088B/zh not_active Expired - Fee Related
  • 2009-07-21 EP EP09736255A patent/EP2324232A1/de not_active Withdrawn
  • 2009-07-21 JP JP2011525589A patent/JP2012502218A/ja active Pending
  • 2009-07-21 WO PCT/FR2009/051455 patent/WO2010026322A1/fr active Application Filing
  • 2009-07-21 US US13/062,013 patent/US8333110B2/en not_active Expired - Fee Related
  • 2009-07-21 CA CA2735534A patent/CA2735534A1/fr not_active Abandoned

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