AU3579099A

AU3579099A - Air-supply device and method of regulating the air supply in a vehicle

Info

Publication number: AU3579099A
Application number: AU35790/99A
Authority: AU
Inventors: Henry Strobel
Original assignee: Mannesmann VDO AG
Current assignee: Mannesmann VDO AG
Priority date: 1998-07-02
Filing date: 1999-06-22
Publication date: 2000-01-20
Also published as: JP2000094926A; KR20000011426A; BR9902527A; DE19829567A1; EP0968858A1

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): oooo oooo oe oo oeo oo o• e• MANNESMANN VDO AG Invention Title: AIR-SUPPLY DEVICE AND METHOD OF REGULATING THE AIR SUPPLY IN A

VEHICLE

The following statement is a full description of this invention, including the best method of performing it known to me/us: Air-supply device and method of regulating the air supply in a vehicle The invention relates to a device for supplying air into the interior of a vehicle, having an air duct with at least one air-inflow opening and air-outflow opening and having a fan motor which is arranged between the air-inflow opening and air-outflow opening and is intended for delivering the air from the air-inflow opening to the air-outflow opening, and also relates to a method of regulating the rotational speed of a fan motor of an air-supply device of a vehicle.

For the purpose of ventilating the interior, motor vehicles have an air-supply means in the case of which outside air is delivered via an air-inflow opening, by means of an air duct, to air-outflow openings in the vehicle interior. In the case of high speeds, it is

S

possible for a sufficient quantity of air to be delivered into the interior without additional S 25 auxiliary means. The operation of a fan, however, is usually necessary in order to transport a sufficient quantity of air. In order to satisfy the comfort-related requirements of the vehicle occupants and to be able to provide the quantities of air required, for example, as a result of different weather conditions, the rotational speed of the fan motor can be set by the driver in a continuously adjustable manner or in stages. The air supplied can usually be heated by heat exchangers provided in the air duct and, in the case of vehicles with an air-conditioning system, cooled as well. For rapid heating or in the case of vehicles with an air-conditioning system cooling of the vehicle interior, and when windows have been iced up or misted up, a large quantity of air is 2delivered into the interior by a high rotational speed of the fan motor. In contrast, under normal driving conditions and when the interior has already been temperature-controlled in accordance with the wishes of the occupants, a lower rotational speed of the fan motor will be sufficient in order to transport the quantity of air required into the interior. For normal ventilation, a lower rotational speed of the fan motor is thus set, this usually only being changed by the driver from time to time during the journey.

As has already been indicated in the introduction, the quantity of air delivered is influenced not just by the rotational speed of the fan motor but also by the 15 driving speed. The quantity of air delivered into the interior is also influenced by the vehicle occupants, by way of the degree by which the air-outflow openings are open. In particular in the case of air-outflow '"-openings which are not open to the full extent, or which are even just open to a slight extent, or some of which are closed to the full extent, situations arise, depending on the driving speed, where, for the purpose of ventilating the vehicle interior to a sufficient extent, it is possible to dispense wholly or partially •go* S 25 with the aid of the fan, as a result of which it is possible to save energy. This is where the present invention comes in, then, the object of which is to propose a device which is intended for supplying air into the interior of a vehicle and by means of which, in relation to conventional devices, it is sought to save energy while, at the same time, increasing the comfort for the vehicle occupants.

The object is achieved according to the invention in that, in the case of a device of the generic type for supplying air into the interior of a vehicle, means are provided for the purpose of regulating the rotational speed of the fan in dependence on the pressure produced 3in the air duct. In accordance with the method of the invention, the rotational speed of the fan is regulated in dependence on the air pressure in the air-supply device.

The measures according to the invention achieve the situation where the air pressure in the region of the ventilating duct between the fan and the air-outflow openings remains largely constant, to be precise irrespective of the degree by which the air-inflow and air-outflow openings are open or of the driving speed.

If, for example, some of the air-outflow openings are closed partially or to the full extent then, with otherwise identical conditions, the rotational speed of S 15 the fan can be reduced in order to maintain the predetermined pressure in the air duct. As a result of the then reduced energy consumption of the fan motor, this means that energy is saved. At the same time, however, it is also possible to achieve an improvement in ventilation. Without the measures according to the invention, the full or partial closure of some of the air-outflow openings, along with an unchanged rotational speed of the fan motor, results in an increase in the pressure in the air duct. This increase S 25 in pressure may result, in particular if the air-outflow openings are only open to a small extent, in flow-related noise, which is annoying to the vehicle occupants. This flow-related noise is avoided by virtue of the air pressure in the air duct being kept constant according to the invention.

At least one pressure sensor is provided in the air duct, said pressure sensor determining the air pressure in the air duct. The measuring signal of the pressure sensor is supplied to a regulating device, which regulates the rotational speed of the fan motor so as to produce a constant pressure in the air duct. The driver of the vehicle can then predetermine the 4 specified value for the air pressure in the air duct from the passenger compartment, as has similarly been the case with the control means for the rotational speed of the fan motor which has been used up until now.

It is also possible to provide in the air duct a plurality of pressure sensors, of which the measuring signals are supplied to the rotational-speed-regulating means. This is important, in particular, in the case of vehicles with a plurality of air-outflow openings since, here, local differences in pressure may arise in dependence on the degree by which the air-outflow openings are open. The pressure sensors may then also 15 be fitted, in particular, in the individual partial air-supply means to the various air-outflow openings.

This provides the further advantage that from the :measured value for the (positive) pressure in each partial air duct and from the opening angle of each air-outflow opening, it being possible for said angle to be sensed via a (position) sensor, it is possible for the quantity of air flowing into the vehicle interior via the air-outflow openings to be determined particularly precisely and evaluated for further e 25 regulating purposes.

S: The pressure sensors used may be absolute-pressure sensors or differential-pressure sensors, although the latter are preferred.

The invention is explained in more detail hereinbelow with reference to an exemplary embodiment and the figures, in which: Figure 1 shows the schematic illustration of a device according to the invention, 0 Figure 2 shows the schematic illustration of a regulation loop for implementing the method according to the invention, and Figure 3 shows an air-supply device of a vehicle with a plurality of air-inflow and air-outflow openings.

A device according to the invention is illustrated schematically in Figure 1. The air duct 1, which directs the air into the interior of the vehicle, has an air-inflow opening 2 and an air-outflow opening The incoming air is compressed by a fan 4, with the result that a positive pressure is produced in the 15 region between the fan 4 and air-outflow opening The compressed air is directed through the air-outflow opening 10 into the interior of the vehicle. According to the invention, in the air-supply means, a pressure sensor 5 is provided in the air-duct region la between the fan 4 and the air-outflow opening 10. The pressure sensor 5 measures the positive pressure in the air duct. The rotational speed of the fan 4 is regulated in dependence on the measured value of the pressure sensor. The air pressure in the air-duct region lb 25 between the air-inflow opening 2 and fan 4 is also dependent on the driving speed, with the result that, with a sufficiently high driving speed, the fan motor can be switched off altogether and the pressure in the air-duct region la can be kept constant, according to a particular embodiment, by automatic, partial closure of the air-inflow opening 2.

As is illustrated in Figure 2, in order to implement the method according to the invention, the measuring signal of the pressure sensor 5 is supplied to a controlling and regulating unit 7. In addition to the signal of the pressure sensor 5, the controlling unit is also supplied a specified value for the air supply 6into the interior, said value being set by the driver in the interior by means of an operating element. The operating element corresponds to the hitherto used switch for the rotational speed of the fan, the difference being that, instead of a constant rotational speed of the fan, it is now the value for the positive pressure in the air-duct region la which is set. In dependence on the measured value of the pressure sensor the controlling and regulating unit 7 then selects the rotational speed of the fan motor 4a such that the pressure in the air-duct region la corresponds to the specified value selected by the driver. For this purpose, it is possible, for example, for the voltage at the fan motor 4a to be varied by the controlling and 15 regulating unit 7. If the pressure measured by the pressure sensor 5 is higher than corresponds to the value selected by the driver by means of the operating element, then the voltage at the fan motor, and thus the rotational speed of the latter, is reduced. If, in the case of a driving speed, the desired pressure in the air-duct region la is achieved even without the fan, then the latter can be switched off altogether.

If, when the fan motor has already been switched off, the pressure in the air-duct region la increases 25 further, for example, as a result of a very high driving speed and/or air-outflow openings which are only open to a small extent, then, according to a 9* e particular embodiment, the air-inflow opening 2 can be closed partially by the controlling and regulating unit 7. For this purpose, an actuating motor receives appropriate signals from the controlling and regulating unit 7 for the purpose of actuating a flap (not depicted) in the air-inflow opening 2. This means that it is possible to maintain a constant pressure in the air-duct region la under all operating conditions.

If the air-outflow openings 10 have sensors for the purpose of determining the degree by which the closure 7flaps are open, then it is also possible for this information (input channels for two opening angles a and P are depicted in Figure 2) to be supplied to the controlling unit 7. Via the input variables positive pressure in the air-duct region la and opening angle of the air-outflow openings, it is also possible for the quantity of air flowing into the interior to be determined in the controlling unit.

Figure 3 illustrates an air-supply device in the specified form of an air-conditioning system in the motor vehicle 12. The air-conditioning system has two air-inflow openings, namely a fresh-air supply means with fresh-air flap 2a and a recirculated-air supply 15 means with recirculated-air flap 2b. The ratio of fresh air to recirculated air is determined by the position of these flaps 2a, 2b, which are set via motors 13, 14.

The inflowing air is compressed by the fan 4, flows through a first heat exchanger 6, for the purpose of cooling and drying the air, and if appropriate, depending on the position of the temperature flap 9, a second heat exchanger 8, for the purpose of heating the air to the desired temperature. In the exemplary embodiment illustrated, the air is directed by way of 0 25 the air duct to three outflow openings 10, which guide the air flow into the footwell, the upper-body region and in the direction of the windows. Provided in the 0 partial air ducts to the outflow openings 10 are flaps 11, by means of which the outflow openings can be closed partially or to the full extent in accordance with the requirements of the vehicle occupants.

Installed in the air-duct region la between the fan 4 and the outflow openings 10, in the exemplary embodiment specifically between the second heat exchanger 8 and the outflow openings 10, is a differential-pressure sensor 5, via which the positive pressure in said air-duct region is measured. The measuring signal is supplied to the controlling and 8 regulating unit 7. The comparison of the positive pressure measured with a specified value set by the driver, by means of an operating element in the passenger compartment, gives the controlled variable for the fan motor, i.e. the voltage at the fan motor, and it is thus possible for the rotational speed of the fan to be increased or reduced by the controlling and regulating unit 7 in order to adapt the pressure in the air duct to the specified value. If the fan motor has already been switched off, the pressure is regulated via the opening and closing of the flaps 2a and/or 2b in the air-inflow openings. For this purpose, the controlling and regulating unit 7 sends appropriate control commands to the motors 13 and 14, respectively.

As the exemplary embodiment has illustrated, the :'...air-supply device according to the invention can save :energy since the fan motor is always operated just at the rotational speed which is necessary in the respective operating state. If appropriate, it is even switched off altogether by the controlling and .regulating unit. Furthermore, a constant positive pressure in the air duct, however, also reduces the annoying occurrence of noise in the case of air-outlet 0 0.0*0 25 openings which are closed partially or to the full extent.

a. 0 For the purposes of this specification it will be clearly understood that the word "comprising" means "including but not limited to", and that the word "comprises" has a corresponding meaning.

Claims

2. The device for supplying air into the interior of a vehicle as claimed in claim 1, wherein arranged "between the fan and the air-outlet opening is at least one pressure sensor of which the signal is supplied to a controlling and ~regulating unit (7)
3. The device for supplying air into the interior of a vehicle as claimed in claim 1 or 2, wherein a plurality of pressure sensors are provided.
4. The device for supplying air into the interior of a vehicle as claimed in one of the preceding claims, wherein a plurality of air-outflow openings (10) are provided, and a pressure sensor is provided in the air duct to each air-outflow opening. The device for supplying air into the interior of a vehicle as claimed in one of the preceding 10 claims, wherein the pressure sensors are differential-pressure sensors.
6. The device for supplying air into the interior of a vehicle as claimed in one of the preceding claims, wherein means are provided for the purpose of determining the degree by which the air-outflow opening(s) (10) is/are open.
7. The device for supplying air into the interior of a vehicle as claimed in one of the preceding claims, wherein means are provided for the purpose of changing the degree by which the air-inflow opening(s) is/are open.
8. A method of regulating the rotational speed of a fan motor (4a) of an air-supply device of a vehicle, said device having an air duct with at least one air-inflow opening and air-outflow opening having a fan which can be regulated and having means for regulating the rotational speed of the fan, wherein the rotational speed of the fan is regulated in dependence on the air pressure in the air duct.
9. The method as claimed in claim 8, wherein the air pressure in the air-supply device is additionally regulated by virtue of the degree by which the air-inflow opening(s) is/are open being changed. Dated this 22nd day of June 1999 MANNESMANN VDO AG By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia