GB2034933A

GB2034933A - Regulating apparatus for a heating or air conditioning installation

Info

Publication number: GB2034933A
Application number: GB7936358A
Authority: GB
Original assignee: Behr GmbH and Co KG
Current assignee: Mahle Behr GmbH and Co KG
Priority date: 1978-10-25
Filing date: 1979-10-19
Publication date: 1980-06-11
Also published as: SE7908815L; DE2846444C2; FR2439946B1; GB2034933B; DE2846444A1; SE440633B; IT1165331B; FR2439946A1; JPS5559014A; IT7926766A0; ES485354A1

Abstract

In a temperature control arrangement, e.g. for a vehicle interior, an electronic regulator 9 (Fig. 1) responds to temperature signals from sensors 5, 6, 7 and desired temp. setter 8, to control the delivery of an air pump 17 by controlling the excitation frequency or amplitude of the pump winding 21. The pump delivers pressurized air to a pneumatic actuator 11 which adjusts an air flap 4 until the interior temperature detected by sensor 6 equals the desired temperature. The flap is movable between limits wherein a forced air is caused to pass through a heat exchanger 3 or by-pass it. Alternatively the actuator 11 may adjust a valve in a heating water pipe. During steady state conditions excess air is vented to atmosphere via a throttle 15, or alternatively, via a solenoid operated valve 24. Alternative pump arrangements are shown in Figs. 2 and 3. Sensor 5 detects external air temperature and optional sensor 7 detects the temperature in air duct 12 downstream of the heat exchanger. <IMAGE>

Description

SPECIFICATION Regulating apparatus for a heating or airconditioning apparatus The invention relates to a regulating apparatus, particularly but not exclusively for vehicles, for a heating or air-conditioning installation with an electronic regulator loadable as a function of temperature through temperature probes which, through at least one servomotor, adjusts at least one final control element, for example an air flap or water valve, as a function of the temperature wherein the servomotor is constructed as a pneumatic servo capsule and the regulator, through an air pump, influences the air pressure in the servo capsule.

An electro-pneumatic regulating apparatus is known from UK Patent Specification No.

1,205,946, wherein a final control member is operated through a pneumatic servomotor and the air pressure in the servomotor is generated by an air pump which is in turn controlled by an electro-pneumatic relay. In this case the pressure in the servomotor is fed back through a concertina to the electro-pneumatic relay, whilst a comparison is made through a lever system with a probe-dependent magnetic force. By means of the lever an electro-pneumatic contact is operated which firstly switches the air pump on and off and secondly opens and closes the pressure system. This arrangement produces an intermittent operation of the air pump, which acts as a disturbing factor upon the adjusting pressure, which is disadvantageous because consequently vibrations of the servomotor and hence of the final control member occur.

A temperature-dependent electronic regulating switch for a regulating apparatus is known from UK Patent Specification No. 1 397426.

In this known apparatus the negative pressure generally available in a motor vehicle is controiled through relays or transistors with the aid of solenoid valves.

Temperature regulation systems in motor vehicles generally utilise the negative pressure available from an internal-combustion engine, whilst the adjustment of a final control member is obtained by corresponding modulation of the negative pressure. It is disadvantageous in this respect that the negative pressure peculiar to the vehicle fluctuates as a function of the operating behaviour of the internalcombustion engine and that on the other hand an effect upon the internal-combustion engine, e.g. upon the carburettor, occurs due to the use of the negative pressure for control movements.

In other cases, particularly in the case of vehicles driven by diesel-type internal-combustion engines, however, very little negative pressure or none at all is available.

It is therefore the underlying aim of the invention to provide a regulating apparatus which even in cases where no or insufficient negative pressure is available from the vehicle, a simple, permanently acting, electopneumatic temperature regulation is created.

According to one aspect of the invention there is provided regulating apparatus for a heating or air-conditioning installation, with an electronic regulator loadable as a function of temperature through temperature probes, which through at least one servomotor adjusts at least one final control member, as a function of temperature the servomotor being constructed as a pneumatic servo capsule and the regulator, through an air pump, influencing the air pressure in the servo capsule, wherein the air pump is permanently excited by the regulator and co-operates with air supply or evacuation means which are present in an ambient air branch connected to a pressurised air supply pipe, and the delivery of the air pump is controlled by the electronic regulator.

According to another aspect of the invention there is provided regulating apparatus for a heating or air-conditioning installation, with an electronic regulator loadable as a function of temperature through temperature probes, which, through at least one servomotor, adjusts at least one final control member, as a function of temperature, the servomotor being constructed as a pneumatic servo capsule and the regulator, through an air pump, influencing the air pressure in the servo capsule, wherein the air pump and air supply or evacuation means which are present in an ambient air branch are connected to a pressurised air supply pipe and co-operate with the air pump and are controlled by the regulator in such a way that the signal of the regulator for the adjustment of the final control memberin one direction of adjustment is passed to the air pump and in the other direction of adjustment to the air supply or evacuation means.

The invention has the advantage that, compared to the apparatus disclosed in Patent Specification No. 1,205,946, the electropneumatic (pressure) transducer is eliminated.

Thus a reduced risk of faults and a substantial reduction in cost is achieved. Moreover, due to the elimination of the intermittent operation of the air pump, the regulating behaviour of the final control member is improved.

By the use of an air pump to generate the air pressure for the servo capsule/s it is possible to generate a relatively low negative pressure, whereby the use of small servo capsules is made possible, leading to a spacesaving construction.

According to a preferred embodiment of the invention, the air pump is arranged to provide an above-atmospheric pressure, whereby the use of even smaller servo capsules is made possible.

According to an advantageous preferred development of the invention, the air pump is constructed- as a dipping armature diaphragm air pump, and the regilator is corrected electrically to a coil aecommodating~ the~dipp- ing armature, the delivery of the air pump being determined by controlling then pump frequency or the-pump- amp1itude:: According to a? preferred variant of the inventidn the air pump is constructed-as-a- diaphragm air punip driven by an eccentric, the regulator being. connected to an electric drive motor which drives the eccentric, the delivery of the air pump being determined by controlling the speed of the pbmp drive motor.

Advantageously, the- air supply or evacua-- tion means in the ambient air branch pipe may be constructed as- a throttle.

In this case, the throttle in the- ambient air branch pipe may. be- constructed as a diame-tral shutter.

According to an alternative- embodiment- of the invention, a controllable solenoid valve is provided as air supply or evacuation means.

As a further development of the irivention it is convenient if a non-return-valve- is arranged in the pressurised air supply pipe.

The regulating properties of the apparatus according to the invention are still further improved if a feedback potentiometer arranged in the- adjustment path of the final control rnember is connected to the electronic regulator.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 shows a first embodiment of regu- lating apparatus which operates with- overpressure, Figure 2 shows a second embodiment in which negative pressure is used, and Figure 3 shows an embodiment with an electric drive motor for the air pump Figs. 1 and 2 show schematically two embodiments of a heating or air-conditioning installation of a motor vehicle with regulating apparatus according to the invention.

The heating or air-conditioning instaltation 1 has, in an air duct 29 a fan 2 and a heat exchanger 3. In the air duct 29, conveniently in a region in which the cross-section of the duct is constricted, an air flap 4 is pivotably arranged in such a way that, in one limit position of the flap 4, the air induced by the fan 2 is forced through the heat exchanger 3 and, in another limit position of the air flap 4, the induced air bypasses the heat exchanger 3.

A final control member 11 in the form of a vacuum servo capsule, serves to adjust the position of the air flap 4. The air pressure acting on the vacuum servo capsule 11 is determined, by an air pump 1 7 through en air pipe 12 and an air pipe 13 in which e hon-- return valve 16 is arranged. Said ali pump 17 is represented as a dipping armature diaphragm air-pumpin the embodiments illus traded in--Figs-. 1 and 2. In this air pump a dipping-armature 20 dips into a coil 21 more or less deeply depending upon the degree of excitation of the coil 21.The- dipping armature 20 is- connected to- a diaphragm 19. In the-enabodiment illustrated in Fig. 1 the pump- 1 7' acts as an overpressure pump and the movement of th-e--diaphragm generates pres- surmised air in a- housing 1 18 with the aid of an inlet valve 26 The dipping armature coil 21 is connected electrically through a control line 22 to an electronic regulator 9. The electronic regulator 9 is provided with electrical supply connections 1 0 which are connected, or may be- connected through a-switch, to an electrical system of the motor vehicle.

The electronic regulator 9 is controlled by temperature probes, shown as an external temperature- probe 5, an internal temperature probe 6 and optionally an outlet temperature probe which measures the air temperature in the air duct 29 downstream of the heat exchanger 3, are connected in series. Conveniently, this series arrangement also includes a temperature desired value adjuster 8, by which it is possible for the vehicle passengers to readjust a specific internal temperature in the passenger compartment.

An embodiment of an electronic regulator 9 is described in UK Patent Specification No.

1397426.

In an ambient air branch pipe 14, which is open to the atmosphere, a diametral shutter 23 is arranged at a throttle position 15. As indicated by dashed lines, it is also possible instead of the diametral shutter 23 for a solenoid valve 24 controlled by the electronic regulator 9 through a line 25 to be provided.

The embodiment illustrated in Fig. 2 differs from the embodiment of Fig. 1 substantially in that the dipping armature diaphragm air pump 1 7" is constructed as a vacuum pump.

Instead of the inlet valve 26 in the embodi anent according to Fig. 1, an outlet valve 27 is provided. In the use of an air suction pump 17" according to Fig. 2, the non-return valve 16' is operative in the reverse flow direction compared to Fig. 1. The remaining construction corresponds to the embodiment according to Fig. 1.

The described regulating apparatus operates in the following manner The probes 5, 6, 7 and optionally the desired value adjuster 8 of the probe chain emit appropriate input signals for the electronic regulator 9, which is in turn connected electrically by a line 22 to the dipping armature coil 21. Said dipping armature 20 controls and operates the diaphragm 19 of the air pump 17' or 17" which, as explained, is constructed as an overpressure pump or vac uum pump respectively. In order to control the delivery of said air pump 17' or 17", either the frequency of excitation of the coil 21 is controlled by the electronic regulator 9, or the strol < e of the dipping armature 20 is modified by the regulator 9. As explained, the air pump 17' or 17" is connected pneumatically to the servo capsule 11.The non-return valve 1 6 serves to prevent a pressure drop in the servo capsule 11. The air pump 17' or 17" works against the throttle 1 5. As a further development the servo capsule 11 or the air flap 4 is provided with a feedback potentiometer 28 which feeds back the position of the flap 4 to the electronic regulator 9.

This produces a closed regulation circuit.

As soon as a differential value between desired value and actual value of the temperatures is detected by means of the probe chain or of individual probes, an input signal or signals passes to the electronic regulator 9 which converts the signals and passes them on as an output to the coil 21 which thus drives the air pump 17' or 17", which in turn generates the required pressure.

Said pressure is communicated through the said non-return valve 1 6 to the servo capsule 11 whilst in steady-state conditions excess air is vented through the throttle 23. The air flap 4 is adjusted by the loading of the pressure capsule 11. This causes a corresponding variation of the temperature in the passenger compartment. The temperature variation by adjustment of the air flap 4 is continued until the attainment of the desired temperature adjusted by the desired value adjuster 8 is sensed by the internal temperature probe 6.

As explained, instead of the throttle 23 a solenoid valve 24 may be provided which opens or closes the outlet from the ambient air branch pipe 14. Where a throttle 23 is used, permanent running of the air pump 17' or 17" is necessary in order to maintain the requisite pressure in the servo capsule 11.

Where a solenoid valve 24 is used, the air pump 17' or 17" need only operate during the adjusting process of the air flap 4, but not in the respective limit position.

The invention is not restricted to the embodiment illustrated and described. Thus, instead of the air flap 4 in an air duct 29, a valve in a hot water circuit, e.g., of a cooling system of a water-cooled internal-combustion engine of the vehicle, may be provided, which delivers a respectively required quantity of hot water to a heat exchanger which then delivers appropriately warmed air into the passenger compartment. The operation of the water valve as a function of the instantaneous temperature may be effected in analogous manner by the electronic regulator 9. The described pneumatic device then serves to adjust the valve.

According to a variant of the invention illustrated in Fig. 3, instead of a dipping armature diaphragm air pump 17' or 17", a diaphragm eccentric air pump 17"' is used which is driven by an electric drive motor 30 through an eccentric 31. The control of the drive motor 30 is effected by the control of its speed by the electronic regulator 9. By this means the delivery of the air pump 17"' can be controlled completely continuously. Also in this variant the air pump 17"' may be constructed as a pressure pump or as a suction pump.

Claims

1. Regulating apparatus for a heating or air-conditioning installation, with an electronic regulator loadable as a function of temperature through probes, which through at least one servomotor adjusts at least one final control member as a function of temperature, the servomotor being constructed as a pneumatic servo capsule and the regulator, through an air pump, influencing the air pressure in the servo capsule, wherein the air pump is permanently excited by the regulator and cooperates with air supply or evacuation means which are present in an ambient air branch connected to a pressurised air supply pipe and the delivery of the air pump is controlled by the electronic regulator.

2. Regulating apparatus for a heating or air-conditioning installation, with an electronic regulator loadable as a function of temperature through temperature probes, which, through at least one servomotor, adjusts at least one final control member as a function of temperature, the servomotor being constructed as a pneumatic servo capsule and the regulator, through an air pump, influencing the air pressure in the servo capsule, wherein the air pump and air supply or evacuation means which are present in an ambient air branch are connected to a pressurised air supply pipe and co-operate with the air pump and are controlled by the regulator in such a way that the signal of the regulator for the adjustment of a final control member in one direction of adjustment is passed to the air pump and in the other direction of adjustment to the air supply or evacuation means.

3. Apparatus according to claim 1, wherein the air pump is constructed so as to generate a pressure above atmospheric.

4. Apparatus according to claim 1 or 3, wherein the air pump is constructed as a dipping armature diaphragm air pump and the regulator is connected electrically to a coil accommodating the dipping armature the regulator determining the delivery of the air pump by controlling the pump frequency or the pump amplitude.

5. Apparatus according to claim 1 or 3, wherein the air pump is constructed as a diaphragm air pump driven by an eccentric and the regulator is connected to an electric drive motor for driving the eccentric, the delivery of the air pump being determined by controlling the speed of the drive motor.

6. Apparatus according to claim 1, 3 or 5, wher & n- the air supply or evacuation rneåns includes a throttle.

7. Apparatus according to claim 6, wherein the throttle in the ambient air breach is constructed as a diametral shutter.

8. Apparatus according to claim 2, wherein a controllable- solenoi'd valve serves fo control air supply or evacuation means.

9. Apparatus according to any one of claims 1 to 8, wherein a non-return valve is arranged in the pressurised air supply pipe.

10. Apparatus according to any one- of claims 1 to 9 including a feed back potentiometer in the adjustment path of the final control member connected to the electronic regulator.

11. Apparatus according to any one of claims 1 to 10 wherein the control member is adapted to control án air flow or water flow through the heating or air-conditioning installation.

12. A heating or air-conditioning installation including apparatus as claimed in any one of claims 1 to 11.

13. Regulating apparatus for a heating or air-conditioning installation substantially as described herein with reference to and as illustrated in Figs. 1 or 2 or Figs. 1 or 2 as modified by Fig. 3 of the accompanying drawings.