FR2530731A1 - TEST BENCH FOR ADJUSTING MIXING DEVICES FOR SUPPLYING INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

THIS TEST BENCH SERVING TO ADJUST THE DEVICES IN WHICH THE MIXTURE OF AIR AND FUEL IS PREPARED TO SUPPLY INTERNAL COMBUSTION ENGINES, THESE DEVICES INCLUDING INJECTION DUCTS 8 CARRIED OUT BY THIS MIXTURE. THE AIR THAT IS VEHICLE IN THESE DUCTS MUST BE MEASURED DOWNSTREAM OF SUCH A DEVICE 4 INSTALLED ON THE BENCH, AT THE SAME TIME AS THE AIR PASSING THROUGH THE SUCTION CHANNEL OF THIS DEVICE, AND THIS WITHOUT SIGNIFICANT QUANTITIES OF FUEL IS CONTAINED IN THE AIR THE BENCH DISCHARGES TO THE ATMOSPHERE. TO ACHIEVE THIS, THE INJECTION DUCTS 8 OPEN INTO A MANIFOLD 10 BETWEEN DEVICE 4 AND AIR FLOW METER 2, THIS MANIFOLD 10 BEING MAINTAINED AT ATMOSPHERIC PRESSURE BY MEANS OF A PASSAGE 13 WHOSE SECTION CAN BE ORDERED, AND THE FUEL IS ELIMINATED IN SEPARATORS 11 IN THE FIELD OF THE COLLECTOR.

Description

1 - The present invention relates to a test bench

  for the adjustment of devices for

  a mixture of air and fuel intended to supply a

  internal combustion engine, these devices

  both, opening upstream of the engine intake valves, injection ducts of the mixture of air and fuel, a vacuum being generated in a suction pipe downstream of the device for producing said mixture, this device having a throttle and being installed

  on the bench, several prescribed air flow rates,

  corresponding to different engine speeds, which can be generated on the test bench, while

  on a value the pressure between the device

  mixing the mixture and the air flow meter and that

  the opening of the throttle valve is adjusted.

  It is described in US Pat. No. 3,528,080 an apparatus with which the adjustment of the

  air mass flow must be carried out by

  pressure in an enclosure between the

  pillon and a Laval nozzle operating in regime

  supercritical, by varying the position of the papil-

  lon -When the carburetor test is continued, so also when adjusting the idling mixture, this adjustment takes place at the same time as fuel is added. The passage of a mixture of air and fuel has as a consequence, we can not

  make adjustments beyond the measurement of a

  their density, because the density also varies with the fuel content When a mixture of air and fuel flows in a carburettor, the measuring apparatus must be placed

  in a temperature-controlled chamber because a

  evaporating fuel removes calories from the environment

  which not only creates differences

  temperature at the switchgear, for example

  pills and nozzles, but also varies the flow of -2- air masses as a result of uncontrollable variations

the density of the air.

  In DE 1,922,902 there is described an apparatus in which the flow rate of the air masses upstream of the carburettor is measured so that the measurements can not be distorted as is the case.

  case with other equipment in which

  the flow rate of the air and fuel mixture.

  The known test benches used to adjust the

  devices for the preparation of the mixture of air and

  have the disadvantage of requiring, because they

  operate on mixtures, construction

  special events for, before we send to the

  mosphere the air that went through these devices, separate

the fuel.

  The problem was therefore to create a test bed that avoids this inconvenience and sends

  air in the atmosphere This problem is

  solution of the present invention which, for this purpose,

  sees a test bench in which the pressure downstream of the mouths of the injection ducts is, in

  a manifold that opens into the suction line

  between the throttle and the flowmèekie, maintained at atmospheric pressure by means of a controlled passage, while the fuel passing through the injection pipes is eliminated in

  separators downstream of said mouths.

  An exemplary embodiment of the invention is described in detail below with reference to the single figure.

of the attached schematic drawing.

  To operate the equipment a vacuum pump (not shown) is connected downstream of the arrow 1 The supercritical nozzle 2 installed for the measurement of the air flow to obtain and having a

  part is located downstream of the device for

  mixing of the mixture 4 to be installed on the

  this means that this device is of

  easy for all adjustment operations.

  It is possible to adjust, practically without interruption, the air flow rate that the nozzle 2 passes, by means of a control rod 5, of tapered shape, which can be displaced in the axial direction. The pressure difference required for this nozzle to reach the speed of sound is, because of the recovery of

  pressure in the flared part of the nozzle 2, if

  it is possible that it is possible to set upstream of the latter, that is to say downstream of the device 4 for producing the mixture, in

  the suction pipe 15, a pressure corresponding to

  pressure in the suction line of the

  engine at the speed chosen for this one.

  To establish a preselected airflow cor-

  responding to a specific engine speed, a nozzle

  supercritical calibration (not shown) is

  in the receiver body 3 and the control unit 8 is moved until the indicating device 6

  displays the pressure corresponding to this airflow.

  This pressure imposed on the adjustable nozzle is likewise

  time the simulated pressure in the suction line.

  allowed engine speed Various values of

  pressure can be graduated and these values can be

  For example, by positioning using the apparatus 7 As soon as the apparatus is calibrated, the calibration nozzle is removed, the

  device for making the mixture on the body

  3 after interposition of a seal, and this device is fixed to this body The device

  of mixing 4 comprises

  jection 8 of the mouth 9 of each of which comes out a mixture of air and fuel This is done in

  a collector 10 in which separators are arranged

  11, for example through the intermediary of

  electronic weighing lances 12, determine in

  The collector 10 is, by means of a passage 13 which can be controlled in section by a pressure comparator 14, maintained at atmospheric pressure, so that the injection by

  the injection pipes 8 are against the pressure

  atmospheric pressure and that the fuel is well separated because it is not in the form of

  gas, which would be the case if the injection is

  knows against a pressure lower than the pressure at-

mosphérique.

  The collector 10 opens into the driving line of

  15, so that the amount of air passing through the injection ducts 8 and that flowing through the suction channel of the device are measured.

  As the fuel

  tible is separated, it is not rejected to the atmosphere.

  Separating it in the field of the collector

  in a considerably less

  only if its separation was carried out in the field of the suction pipe, because there is no depression in the field of the collector, so

  that the fuel contains almost no

  gaseous, whereas on the other hand it would contain a considerable extent if its separation

  place in the field of aspiration cnd suction.

  The invention is however not limited to a test bench comprising the described flowmeter, because it can indeed use any device

  air flowmeasures designed for low pres-

  the pressure in the suction line, the effective pressure in that line used to calculate the

flow of air masses.

4 - -5 -

Claims (1)

CLAIM   Test bench for adjusting devices for   the mixture of air and fuel intended for   to feed an internal combustion engine, these arrangements   comprising, opening upstream of the engine intake valves, injection-ducts of said mixture, a depression being generated in a   suction line downstream of the device for   ration of the mixture installed on the bench and comprising a throttle valve, several prescribed air flows corresponding to different engine speeds that can be generated at the test bench, while   the value of the pressure between the   mixture development and air flow meter   and that the opening of the butterfly of   This test bench is remarkable in that downstream of the mouths (9) of the injection pipes (8) in a manifold (10) which opens into the   suction line (15) between the butterfly of   the flowmeter (2) the pressure is now   at the atmospheric pressure by means of a passage (13) whose section is controlled, while the fuel which passes into the injection pipes (8) is eliminated in separators (11) arranged in downstream of said mouths (9).