FR2490160A1 - METHOD FOR CONTROLLING AIR VOLUME - Google Patents

Abstract

PROCESS FOR CONTROLLING THE AIR FLOW FOR VENTILATION OR AIR CONDITIONING OF THE INTERIOR OF A CAR, WITH CONTROL OF AT LEAST TWO FLAPS ARRANGED IN AN AIR SUPPLY DUCT AND THE BLOWER ROTATION SPEED . THE FLAPS 7, 8, 9 VARY DEPENDING ON THE SPEED V THE AIR PASSAGE SECTION ON AT LEAST TWO LEVELS, OR THE ROTATION SPEED N OF THE BLOWER VARIES CONTINUOUSLY. THE ROTATION SPEED N GOES FROM ONE EXTREME VALUE TO ANOTHER DURING THE DISCONTINUITIES OF THE AIR PASSAGE SECTION, SO THAT THE AIR PASSAGE SECTION PRESENTS DEPENDING ON THE SPEED V A VARIATION IN GRADES AND THE SPEED ROTATION N PRESENT AS A FUNCTION OF SPEED V A VARIATION IN SAW TEETH.

Description

The present invention relates to a method of controlling the volume of air for

  ventilation or air conditioning of the passenger compartment of a car, with a command of at least two components arranged in a

  air supply ducts and actuated by vacuum capsules.

  for variation of the air passage section, and secondly of the speed of rotation of the blower for variation of the air flow. The invention starts from the heating and / or air conditioning apparatus described in the patent application of the Federal Republic of Germany

published under the number 26 54 552.

  One of the problems posed by the aeration or the air conditioning of

  cars is to maintain the necessary air flow in the

  constant tackle and equal to a given preset preset value.

  The variation of the speed of the vehicle also varies the dynamic pressure in the air intake duct of the vehicle and consequently the air flow in the absence of determined measures for compensation of the dynamic pressure, such as variation of the section of air passage using shutters and / or variation of the speed of rotation

the fan blowing air.

  The aforementioned application describes a method of adjusting the volume of air

  using a manual switch. A determined position of the

  which corresponds to a given section of air passage or position of the flaps and a given rotational speed of the

  blower, is chosen according to the feeling of comfort of the passenger.

  The latter has the possibility of displaying six setpoints which do not remain constant, however, when the speed of the

  car varies; the different instantaneous value must then be correct

  controlled by a new manual adjustment of the air volume switch.

  This distracts the driver's attention and must also be taken into account.

deregulated as a lack of comfort.

  The patent application of the Federal Republic of Germany published under No. 16 80 228 also describes an automatic regulating device, which keeps the air flow rate constant by continuously varying the speed of rotation of the blower on the one hand. and the position of an air shutter on the other hand, depending on the speed of the vehicle. This control device operates with an expensive actuator (plunger coil), which imposes an electrical reaction of the position of the flap. The regulation range of this device is further limited by that of the speed of rotation of the fan; on current cars with a large speed range, such a regulating device would lose its effectiveness; that is, its regulation quality, on the top of the speed range. The invention aims to improve a method for controlling the volume of air of the aforementioned type and a device for implementing said method, so as to automatically maintain in the passenger compartment, at full speed of the car, a volume of constant air and equal to a value

  preset setpoint, and to achieve this objective with a

as simple as possible.

  According to an essential characteristic of the invention, the flaps vary the air passage section, depending on the speed of the car, on at least two bearings, where the speed of rotation of the blower varies continuously, said speed of rotation passing from one

  extreme value to another when discontinuing section of pas-

  airflow section, so that the airflow section according to the speed of the car has a stepped variation and the speed of rotation of the blower according to the speed of the car a sawtooth variation . The automatic control according to the speed of the car ensures a constant air flow over the entire speed range of the car, without the driver

  - with the exception of the single preselection of a set value -

  have to constantly correct by hand during changes in the speed of the car. A comfort requirement is thus optimally satisfied and the driver freed from a function that hinders his attention. Controlling the air flaps in stages allows the use of simple actuators, such as vacuum capsules; sudden variations in the rotational speed, that is to say the

  sawtooth curve, nevertheless produce a constant volume of air.

  The entire rotational speed range of the blower can thus be used for a bearing, that is to say a specific position of the flaps. The quality of the control of the volume of air is thus

  improved over the entire speed range of the car.

  According to another characteristic of the invention, the control of the flaps and the speed of rotation of the blower is ensured by an electronic control unit whose electrical input signals are on the one hand the speed of the car, delivered by the speedometer, and on the other hand the setpoint of the

  the volume of air at the end of the car, delivered by the transmitter of

  sign. A given speed of rotation of the blower, connected to a given position of the flaps, is thus affected in a simple way at each speed of the car, so that the volume of air remains constant. According to another characteristic of the invention, the continuous control of the speed of rotation of the fan on a bearing is provided by a known electronic control device, which makes

  vary the voltage applied to the electric motor of the blower.

  The continuous part of the sawtooth function can, however, also represent any function, delivered by the unit of

electronic control.

  According to another characteristic of the invention, the communication unit

  electronic message includes a specific program of the car,

  in which specified speeds of the latter are introduced.

  picks to fix discontinuities between bearings. This device makes it possible to adapt the control method to different cars,

  and in particular to their speed ranges.

  According to another characteristic of the invention, values

  the speed of rotation of the fan are affected.

  at certain speeds of the car and the various

  between intervals. The difference (discontinuity) in rotational speeds depends on the difference of the air passage sections (section discontinuity), and the velocity (dynamic pressure) at the point of discontinuity. This measurement ensures a precise stabilization of the air flow rate despite instability of the regulators, flaps and blower. The result is a real improvement

comfort.

  Other features and advantages of the invention will be

  better understood using the detailed description below of a

  Embodiment and accompanying drawings in which Figure la represents a diagram of the variation of the speed of rotation n of the blower as a function of the speed v of the car; Figure lb shows a diagram of the variation of the air passage section A as a function of the speed v of the car; FIG. 1c shows a diagram of the variation of the air flow m as a function of the speed v of the car; FIG. 2 represents a block diagram with the elements of the control; and FIG. 3 represents a ventilation installation with

adjustment and actuators.

  Figures la, b and c represent the three functions - vi-

  speed of rotation n of the blower, section A of air passage and air flow mi - depending on the speed v of the car, which is

  for example divided into three levels 0 to I, I to II and II to III.

  FIG. 1 represents the speed of rotation n of the blower

  which, on each of the levels 0 to I, I to II and II to III, varies continuously

  n between a maximum value n and a minimum value n in Max Min At transition points I, II and III of the various stages, the speed

  rotation from one extreme value to another, that is,

  to direden. Aan den. aan and den. at I min min max min min max min min min max or vice versa, so that a sawtooth profile is obtained over the entire range 0 to III of the speed v. In this

  particular embodiment, the speed of rotation can

  be constant beyond the point of discontinuity III, because the influence of the dynamic pressure is practically eliminated when the air passage section is closed; in this case, residual leakage air

  is fed at a constant speed of rotation of the fan.

  Fig. 1b shows the stepped variation of air passage section A over the entire range 0 to III of speed v, and beyond. The air passage section A thus remains constant on

  each of the levels 0 to I, I to II and II to III, and presents a discon-

  at the transition points I, II and III. The air passage section thus has the following values: A in the range from 0 to I, corresponding to a maximum opening; AI on the range I to II, corresponding substantially to half a gap; and AII in the range of II to III, still about 20% of A0. The air passage section is closed beyond the speed at point III, but the leaks produce a certain volume of leakage air which, in this maximum speed range, is substantially constant,

  i.e., independent of the dynamic pressure.

  FIG. 1c represents the air flow rate ih resulting in the

  tackle the car over the entire speed range of the car.

  As the parallel to the abscissa shows, the air flow remains constant and equal to the value im sensed. On the first speed range from 0 to I for example, this results from the fact that for a section of air passage At constant in this range, the rotational speed n of the blower decreases continuously between a maximum value no and a minimum value n I, but in inverse proportion to the growth Imn of the dynamic pressure. When the first point of discontinuity I is reached, for example at a speed of the car of 80 km / h, the air passage section is abruptly reduced from A to AI, while simultaneously the speed of rotation of the fan increases again sharply to a maximum value nI. As the speed v of the car increases, the speed of rotation n decreases again continuously, for a constant air flow section AI,

  up to a minimum value nII min at the point of discontinuity II.

  The air passage section is abruptly reduced at this point

  from AI to AII and simultaneously the speed of rotation of the

  flante suddenly rises up to a maximum value nII ax The

  As the speed of the car continues to increase, the speed of rotation

  The fan decreases again continuously up to a minimum value nIII min at the point of discontinuity III. At the latter, the air passage section is reduced abruptly from AII to AIII, that is to say, completely closed; there is only one flight section left. At the same time, the rotation speed of the fan

  increases sharply to nIII max and can then remain constant

  aunt, even when the speed of the car continues to increase,

  because the leakage rate that appears is practically constant. The condition

  transition should be satisfied at all points in the

  discontinuity I, II and III: the flow of air with a large section of

  wise and low rotational speed of the blower is equal to the low section flow and high speed of rotation of the blower; differences in rotation speeds or heights of bearings

  points of discontinuity 1, II and III result from this condition.

  The difference of rotational speed discontinuities nI Max -

  or. at point I and n - II in point II in relation to the corresponding section differences A - AI and AI - AII results from

  strong non-linearities of the volume of air introduced.

  The block diagram of FIG. 2 represents the main elements for the implementation of the method according to the invention. There is provided an electronic control unit 1, which receives from the speedometer 2 signals proportional to the speed of the car. Another input signal from this unit is the value of

  setpoint of the air flow, that a setpoint indexer 3 makes it possible to

select at will.

  The electronic control unit 1 is electrically connected

  actuators 4, 5 and 6, which control the shutters 7, 8 and 9

  in the air supply duct. These valves vary

  the section of air passage by stage. Servomotors are advan-

  tagously made in the form of depression capsules, attacked

  by all-or-nothing switching solenoid valves. The unity of

  electronic control 1 is further connected to an electronic control

  blower, which delivers its output signals to the electric motor

  11, which drives the blower 12 for the circulation of air in the supply duct. Specific parameters, specific to the car, are stored in the electronic control unit 1; these are the speeds of the car assigned to the various points of discontinuity I, II and III, as well as values of the speed of rotation of the fan, assigned to these speeds of the car according to figure la. When these speeds are reached, the flaps 7, 8 and 9 are opened or closed successively, so as to produce the stepped variation of the air passage section according to FIG. 2 495v16C 1b. The regulation continues, according to a determined function, of the speed of rotation of the fan 12 or of its motor 11 is provided by the electronic control fan 10, which also receives from the electronic control unit 1 its input signals function the speed of the car. Figure 3 shows the part of the ventilation or air conditioning system of a car, which includes the controls, actuators and control devices necessary for the

  of the control method according to the invention. Channel 13 of

  air intake comprises two air inlets 14 and 15, which open

  through the air inlet ducts 16 and 17 in the feed duct.

  13, in which is located the blower with its motor 18 and its wheel 19. In the air intake duct 16 is a shutter 20, that the vacuum capsule 22, equipped with a solenoid valve

  shown, can be moved to the closed position,

  solid line, or in the open position 20 ', represent

  dashed. The second air inlet duct 17 contains a shutter 21, that the double vacuum capsule 23, equipped with solenoid valves

  unrepresented, can be passed in three different positions.

  In addition to the fully closed position and the 21 "fully open position, the flap 21 can occupy as well

  a median position 21 '. Solenoid valves not shown, which

  the vacuum capsules 22 and 23 are connected by electrical lines 24, 25 and 26 to the electronic control unit 28, an electrical line 26 connects, via the electronic fan control 29, to the electric motor of the

19 blower wheel.

  Of course, various modifications may be made by those skilled in the art to the principle and to the devices which have just been described as non-limiting examples,

  without departing from the scope of the invention.

- 8

Claims (5)

claims   1. Method of controlling the volume of air for aeration or cooling   matization of the passenger compartment of a car, with control of at least two parts arranged in an air supply duct and actuated by vacuum capsules for variation of   the air passage section, and on the other hand the rotational speed   of the blower for varying the air flow, said method being characterized in that depending on the speed v of the car, the flaps (7, 8, 9) vary the air flow section A on at least two stages, where the speed of rotation n of the fan varies continuously, said speed n passing from one extreme value to another at the discontinuities of air passage section, so that the passage section A of air as a function of the speed v has a stepped variation and the speed of rotation n of the fan as a function of the speed v a sawtooth variation. 2. Method according to claim 1, characterized in that the flaps (7, 8, 9) and the electric motor (11) of the blower (12) are controlled by an electronic control unit (1), which receives its signals from entry of the speedometer (2) of the car on the one hand   and the set indexer (3) on the other hand.   3. Method according to one of claims 1 and 2, characterized in that   that the continuous control of the speed of rotation of the fan on a bearing is provided by a known device (10) for electronic fan control, which varies the voltage applied to the   electric motor (11) of the blower (12).   4. Device for implementing the method according to a   of claims 1 to 3, characterized in that the unit of   electronic control (1) comprises a specific program of the car, in which specified speeds thereof   are introduced to fix the discontinuities between bearings.   5. Device according to claim 4, characterized in that determined speeds of the speed of rotation of the fan (12) are assigned to specific speeds of the car and to   various discontinuities between levels.