GB2273548A

GB2273548A - Fuel flow control system

Info

Publication number: GB2273548A
Application number: GB9325728A
Authority: GB
Inventors: Peter Bradley; John Sweeney
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-12-16
Filing date: 1993-12-16
Publication date: 1994-06-22
Anticipated expiration: 2013-12-16
Also published as: GB9325728D0; GB2273548B; GB9226159D0

Abstract

A fuel flow control system in a motor vehicle comprises a solenoid-actuated valve mounted in a fuel line, in which the valve member can be held in positions preventing and allowing fuel flow. The valve member may take the form of a magnetic plunger 20 located in a fuel flow channel 13, 15, urged open by a spring 21, with magnets 22 positioned to bias the valve closed. The valve is opened by a control unit (figure 2, not shown) when a code is entered via a keypad. Entering the wrong code will cause an alarm to sound. The valve is closed by the control unit after the engine of the vehicle is switched off, or if an impact is sensed. The control unit may send pulses to the valve while the engine is running to ensure that the valve does not stick in place. The code may be entered using an infra-red remote control unit. <IMAGE>

Description

FLUID FLOW CONTROL APPARATUS This invention relates to fluid flow control apparatus. The apparatus has particular, but not exclusive application in the control of fuel flow along a fuel line. This type of apparatus may have application as an anti theft device for vehicles.

Fluid flow through pipe lines may be controlled by solenoid operable valves. Known valves need a constant power input in order to maintain the valve in an open or closed position. Much energy is lost as heat which, is disapated from the solenoid. If this systems were to be used on a pipe line for flammable fluids such as a fuel line it would constitute a hazard.

The present invention has been made from a consideration of this problem.

According to a first aspect of the present invention there is provided a fluid flow control apparatus comprising a valve having a channel through which the fluid may pass, a valve member operative to move between an open position and a closed position in which fluid flow out of the apparatus is prevented, wherein the valve comprises means for maintaining the valve member in the open position, means for maintaining the valve member in the closed position and means for moving the valve member between the open and closed positions.

Either or both of the means for maintaining the valve member in the open and closed positions comprises at least one magnet or at least one resilient body. The means for moving the valve member between the open and closed positions comprises a coiled conductor which may be energised to produce an electromagnetic field. This field may polarise the valve member or another body connected to the valve member. A current may be sent through the coil in either direction such that the coil may be used to generate opposing magnetic fields. Preferably means such as an oscillator is provided for sending pulsed signals to the coiled conductor to ensure that valve remains in the open position.

By providing means for maintaining the valve member in the open or closed positions it is not necessary to provide a permanent current flow as is the case with conventional fluid flow control apparatus. This results in an energy saving as well as proving safe when used to control the flow of flammable fluids such as fuel.

The invention further provides a method of controlling the flow of fuel through a fuel line by way of fluid flow control apparatus according to the invention.

The invention has particular but not exclusive application as an anti-theft device for vehicles.

In a preferred embodiment, the valve member comprises a plunger located in the channel. Slots or groovesmay be provided along thelength of the plunger either internally or externally or both to facilitate fluid flow through the channel. The plunger is provided with means, such asa spring, to bias the plunger towards the closed or open position.

According to a second aspect of the present invention there is provided a fluid flow control system comprising a fluid flow control apparatus of the invention, input means for inputing data, actuation means for receiving said inputed data and actuating the fluid flow control apparatus in response to appropriate data input.

The input means may comprise a keypad or similar device. The actuation means may comprise a control unit or a decoder unit which transmits signals to the control apparatus in response to appropriate input from the input means.

The system may include impact sensitive means which transmits a signal to the control apparatus in response to an impact so that the valve member, when in the open position, moves to the closed position. Such impact sensitive means may also simultaneously transmit a signal to a fuel pump so that pumping of fuel to the fluid flow control apparatus is stopped.

The system may include means, such as an oscillator, for sending pulsed signals to the valve solenoid to ensure that the valve remains in the open position. Preferably the valve solenoid is pulsed for approximately one micro second every second. However, it will be appreciated that the rate and duration of pulsing may be chosen appropriately depending on the characteristics of the associated valve.

In order that the present invention may be more readily understood specific embodiments thereof will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 shows an apparatus in accordance with the invention, the valve being shown in the closed position; Fig. 2 is a block diagram showing the circuitry of the system of the present invention; Fig. 3 shows the circuitry of the keypad switch of Fig. 2; Fig. 4 shows the solenoid valve switch circuit of Fig. 2; Fig. 5 shows the starter switch circuit of Fig. 2; Fig. 6 shows the time delay switch circuit of Fig.

2; Fig. 7 shows the impact switch circuit of Fig. 2; Fig. 8 is a block diagram showing use of a decoder unit with an apparataus according to the invention; and Fig. 9 is a schematic representation of the circuitry of a system of the present invention according to a preferred embodiment.

Referring to Fig. 1 a fluid flow apparatus 10 comprises a pressed steel case 11 connected to the top of an aluminium body 12. An aperture 13 is provided at the top of the case 11 which acts as an inlet for the fluid. A channel 14 extends from the inlet through the centre of the case and aluminium body and forms an outlet 15 at the base of the aluminium body 14. The channel narrows towards the base so as to form a valve seat 16. 0 rings 17 are provided in the walls of the channel immediately above the valve seat 16. A plunger 18 is located in the channel which is movable from an uppermost position in which the valve is open and a lowermost position in which the valve is closed. A piton sealing washer 19 is provided in the base of the plunger. Slots 20 are provided down the periphery of the plunger so as to allow fluid flow.

The plunger is urged downwardly by a spring 21.

Permanent magnets 22 and an intensifier block are provided at the base of the steel case. A coiled conductor 23 is located above the permanent magnets.

In use the valve is normally maintained in the closed position by the spring 21.

If the valve is to be opened a two second negative electrical pulse is sent to the coiled conductor 23 so as to induce a magnetic field. This urges the plunger to move upwardly. After the pulse has stopped the plunger is retained in the open position by the permanent magnets 22.

In order to close the valve a two second positive electrical pulse is sent to the coils 23. This overcomes the attractive force of the magnets and the spring moves the plunger downwardly into the closed position.

If the valve is located in the fuel line of a vehicle the valve may be activated so as to prevent fuel flowing to the engine so as to immobilise the vehicle.

A block diagram of the circuitry required to utilise the valve in this manner is shown in Fig. 2.

Detailed circuits of the various components are shown in Figs. 3 to 7.

The keypad switch provides an electronic lock which accepts numeric passwords via the attached keypad. The password is defined and can be modified, by the system user. The system retains the password in memory which has a battery powered back up, so that it is retained even when the vehicle's battery is removed.

The output to the solenoid switch and the starter motor is normally low, being pulsed high for two seconds when the correct password is entered.

If three incorrect passwords are entered in succession the alarm output pulses high.

The output from the time delay switch is normally low, whether the vehicle ignition is on or off.

Approximately 12 seconds after the vehicle ignition is turned off, the output pulses high for a few seconds. If the vehicle ignition is turned back on less than 12 seconds after it was turned off the output remains low. This allows the vehicle operater a 12 second period in which to re-start the vehicle in case of stalling.

Turning the ignition on after the 12 second period has no effect on the output (ie it remains low).

The impact switch has one output which is normally high. If the vehicle is involved in an impact such that the inbuilt mechanical impact switch activates, the impact switch transmits a low output pulse for approximately two seconds.

The solenoid switch has two outputs to the solenoid of the latching valve. Normally both outputs are electrically isolated, so that no current flows through the solenoid.

When a logic 1 pulse arrives from the keypad switch, the first output is connected to Ov whilst the second output is connected to +12v. These connections are maintained for the duration of the trigger pulse, causing current to flow in the solenoid. When the input pulse finishes, both outputs are again electrically isolated; hence no current flows through the solenoid.

When a logic 1 pulse arrives from the impact switch or the time delay switch, the first output is connected to +12v whilst the second is connected to Ov. These connections are maintained for the duration of the pulse, causing a current to flow in the reverse direction through the solenoid. When the input pulse finishes, the outputs are again electrically isolated; hence no current flow through the solenoid. Whilst the two solenoid outputs are set by the impact switch or time delay switch, an output to the starter motor switch is held low. When the input pulse terminates this output pulse terminates.

The starter switch has three outputs. Initially, the outputs to the on/off indicators have the on indicator off and the off indicator on. The third output is Ov.

On receipt of a logic 1 pulse from the keypad switch, the indicator outputs are switched to indicate on and the third outputs are latched until a logic 0 input pulse is received from the solenoid switch.

When a logic 0 pulse is received from the solenoid switch, the indicator outputs are again switched so that they indicate off whilst the third output is set at Ov. These outputs are latched until a pulse is received from the keypad switch.

It will be appreciated that the positive and negative outputs may be reversed according to the wiring of the vehicle.

Referring to Fig. 8, in order to improve security the apparatus of the invention may include a decoder unit, the keypad being located on a remote handset unit providing infrared transmission of data to the decoder unit.

If the lid of the decoder box is removed the alarm is activated and disables the fuel valve. The alarm can be cancelled by entering an appropriate code. If the box is to be opened the code should first be entered and the lid removed within a certain period, say ten seconds.

When the car is to be started the key is placed in the ignition. The code is then entered. Each time a key is depressed a pulse is sent to a buzzer that it is clear that the code has been entered. Once the code is entered the unit emits a sound for ten seconds. During this time the ignition key should be rotated in the switch to start the car. Once the ignition switch has been detected the bleeping sound stops. The driver has 15 seconds to start and still has 15 seconds to start the car if the engine stalls.

On vehicles with electric fuel pumps the fuel pump is switched on only when the valve is activated.

When the engine is switched off the driver has a certain time say 15 seconds to re-start the car before the unit deactivates the fuel valve. During the last ten seconds the buzzer bleeps.

The decoder box is fitted to the fuel valve. The infra-red receiver or fixed keypad is fitted within the vehicle cabin. The connection may be made via a small four-core cable. The infra-red receiver unit is useless if removed by a thief.

The infra-red receiver box should be discreetly housed in the cabin of the car - receiver being useless if removed. This may be a small case (pocket pager size or smaller) with 12 digit key pad. The switches may either be of membrane or push-through label type, both of which should be waterproof. The unit may be battery powered.

Referring to Fig. 9, a preferred embodiment of the system of the present invention includes a keypad having a hard wire, infra-red or other remote link to a control unit, which preferably has a battery back-up. The control unit is capable of sending signals to:- a fuel pump, which may for example be electric, via relay RL1C; a diesel cut-off solenoid via relay RL1D; a starter solenoid via a time delay relay RL2, which for example may give a 15 second high output. The output to these units is activated only if the code input via the keypad is accepted by the control unit.

An oscillator, OSC, is introduced into the control circuitry as a safety feature so that no matter what the conditions are the valve will remain open. The oscillator pulses the solenoid valve for a micro second every second. The relays RL1A, B, C, D and the impact relay solenoid RL1E enable the system to shut down on impact.

The start-up procedure is as follows: The ignition is switched on at the ignition switch 51. This activates the time delay switch 52 for say 15 seconds. A code number is then keyed into the control unit via the keypad. If the code is accepted by the control unit, it sends power RL1C to activate the electric fuel pump, to RL1D to activate the diesel shut-off solenoid and to the high power time delay relay switch RL2 to give a 15 second output to the starter solenoid.

The control unit sends a single pulse out through the relays RL1A, B to the solenoid to open the valve and, at the same time, sends power to the Inverted And Gate which has already received the same output from the front and rear impact switches. With both sets of information being equal, i.e. equal inputs to the Inverted And Gate, the Gate will free run allowing the oscillator to pulse.

The front and rear impact switches are normally closed. On impact, the impact switches transmit a signal to the impact relay solenoid RL1E which energises the valve solenoid relay RL1. Then the contacts of the relays RL1A, B, C and D will change over. The polarity change on the RL1A, B contacts closes down the fuel valve while the contact changes on the RL1C, D relays cause the circuits to open or break thereby cutting off supply by the fuel pump and diesel solenoid. Since the information at the Inverted And Gate is now unequal, this will shut down the oscillator.

Thus, the micropulses help to maintain the valve in the open position so that any involuntary closing of the valve for example when travelling over rough terrain is avoided. However, if the vehicle is involved in an accident there is a potential danger in having an open fuel line with the ignition still on and fuel being pumped through the open valve. The use of the two impact switches to shut down the fuel valve avoids this problem and avoids, say, 15 seconds of fuel output.

It will be appreciated that the present invention is not intended to be restricted to the details of the above embodiments which are described by way of example only. For example one or more parts of the system described may be interconnected by direct hard wiring or via electro-magnetic transmission or otherwise.

Furthermore, it will be appreciated that a microprocessor could be programmed to carry out all of the functions of the components for example as shown in Fig. 9. This would allow the size of the system to be reduced. Thus, the control system may include impact switches, a solenoid, a valve and a microprocessor.

Claims

1. A fluid flow control apparatus comprising a valve having a channel through which the fluid may pass, a valve member operative to move between an open position and a closed position in which fluid flow out of the apparatus is prevented, wherein the valve comprises means for maintaining the valve member in the open position, means for maintaining the valve member in the closed position and means for moving the valve member between the open and closed positions.

2. A fluid flow control apparatus according to claim 1 wherein either or both of the means for maintaining the valve member in the open and closed positions comprises at least one magnet or at least one resilient body.

3. A fluid flow control apparatus according to any preceding claim wherein the means for moving the valve member between the open and closed positions comprises a coiled conductor.

4. A fluid flow control apparatus according to any preceding claim wherein means such as an oscillator is provided for sending pulsed signals to the coiled conductor.

5. A fluid flow control apparatus according to any preceding claim wherein the valve member comprises a plunger located in the channel.

6. A fluid flow control apparatus according to claim 5 wherein slots or grooves are provided along the length of the plunger.

7. A fluid flow control apparatus according to claim 5 or claim 6 wherein the plunger is provided with means, such as a spring, to bias the plunger towards the closed or open position.

8. A method of controlling the flow of fuel through a fuel line by way of a fluid flow control apparatus according to claim 1.

9. A fluid flow control system comprising a fluid flow control apparatus according to claim 1, input means for inputing data, actuation means for receiving said inputed data and actuating the fluid flow control apparatus in response to appropriate data input.

10. A fluid flow control system according to claim 9 wherein the input means comprises a keypad or similar device.

11. A fluid flow control system according to claim 9 or claim 10 wherein the actuation means comprises a control unit or a decoder unit which transmits signals to the control apparatus in response to appropriate input from the input means.

12. A fluid flow control system according to claim 9 or any succeeding claim wherein the system includes impact sensitive means.

13. A fluid flow control system according to claim 9 or any succeeding claim wherein the system includes means, such as an oscillator, for sending pulsed signals to the valve.

14. A fluid flow control apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

15. A method of controlling the flow of fuel through a fuel line substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

16. A fluid flow control system substanitally as hereinbefore described with reference to and as illustrated in the accompanying drawings.