GB2322363A

GB2322363A - Fuel vapour collection system

Info

Publication number: GB2322363A
Application number: GB9803472A
Authority: GB
Inventors: Michael Munn
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-22
Filing date: 1998-02-20
Publication date: 1998-08-26
Anticipated expiration: 2018-02-20
Also published as: GB2322363B; GB9803472D0; GB9703745D0

Abstract

A system for collecting fuel vapours released during refuelling of vehicles comprises a first fluid conduit 20 communicating between the inlet 16 of a fuel tank 18 and a vapour collection chamber 28, a pump 22 and valve 26 located in the conduit, and control means such as a management unit 10 for controlling the pump and valve. The system may include a one-way valve 24, and a second fluid conduit with a regulating valve 32 and a charcoal filter (40 fig 1) between the chamber 28 and the engine inlet manifold 36. The system may further include sensors 12, 30, 34, 44, 46 which respectively monitor the presence of a filling nozzle or hydrocarbon vapours in the fuel inlet 14, the pressure in the chamber 28, the pressure in the manifold 36, the engine temperature, and the road speed. The system operates the pump during refuelling to collect fuel vapour in the chamber 28, from where it may be fed to the engine inlet if the operating conditions are appropriate.

Description

Fuel Vapour Collection Apparatus" The present invention relates to apparatus for collecting fuel vapours which are released when volatile liquid fuels are being dispensed from fuel pumps into the fuel tanks of road vehicles. The invention is particularly intended for use with petrol driven vehicles.

When a petrol-driven vehicle is being re-fuelled, significant quantities of petrol fumes are released into the atmosphere. This is increasingly becoming recognised as a significant environmental and health problem. Vapour collection systems intended to address this problem are known. Such systems are incorporated into fuel pumps. However, they have been found to be relatively ineffective in practice.

It is an object of the present invention to provide vapour collection apparatus which will perform more efficiently than known apparatus. In preferred embodiments of the invention, the recovered fuel is recycled by being fed to the vehicle engine.

According to a first aspect of the present invention there is provided fuel vapour collection apparatus for collecting fuel vapour released in the inlet of a vehicle fuel tank during re-fuelling, comprising: fluid conduit means having a first end communicating with said fuel tank inlet and an outlet communicating with a vapour collection chamber; valve means and pump means located in said fluid conduit for controlling the flow of fluid therethrough; and means for controlling the operation of said valve means and pump means.

Said control means preferably includes sensor means adapted to generate a signal for controlling the operation of said valve means and pump means.

Suitably, the sensor is adapted to detect the presence or absence of a fuel dispensing nozzle in said fuel tank inlet. Alternatively or additionally, the sensor includes means for detecting the presence of hydrocarbons in said fuel tank inlet.

Said control means preferably also includes a management unit connected to said sensor means, said valve means and said pump means.

Preferably, said control valve means is located downstream of said pump means in the direction of fluid flow from said inlet to said collection chamber.

Preferably also, the apparatus further includes one way valve means incorporated in said fluid conduit and adapted to prevent fluid flow in the upstream direction from said collection chamber to said inlet.

The collection chamber preferably also includes pressure sensing means for monitoring the fluid pressure inside said chamber. The pressure sensor is preferably connected to said management unit.

The apparatus preferably further includes second fluid conduit means, having an inlet communicating with said collection chamber and an outlet adapted for connection to an inlet manifold of the vehicle engine, and said control means is further adapted for controlling the flow of fluid from said chamber and through said second conduit.

The control means preferably further includes valve means incorporated in said second fluid conduit means.

Optionally, filter means such as an activated charcoal filter may also be incorporated in said second conduit means.

The flow of fluid through said second conduit means may be controlled on the basis of any appropriate criteria, such as collection chamber pressure, engine temperature, engine inlet manifold pressure, engine speed, or vehicle road-speed, or combinations of these.

The control means will further include suitable sensors for this purpose, or connections to existing vehicle systems which can supply suitable signals to the control means.

According to a second aspect of the invention, there is provided a vehicle equipped with a fuel vapour collection system in accordance with the first aspect of the invention.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which : Fig. 1 is a schematic representation of one embodiment of apparatus according to the present invention; and Fig. 2 is a schematic representation of a modified version of the embodiment of Fig. 1.

Referring to Fig. 1 there is shown an embodiment of fuel vapour collection apparatus in accordance with the invention, connected to a fuel tank 18 and internal combustion engine 38 of a motor vehicle. The apparatus is adapted to operate so as to collect fuel vapour when fuel is being supplied to the fuel tank 18, or possibly whenever the fuel tank is open. Optionally, as in this preferred embodiment, the apparatus is further adapted to deliver recovered fuel to the engine 38 at appropriate times.

The fuel tank 18 has a receptacle 14 into which a fuel dispensing nozzle of a petrol pump may be inserted, connected to the fuel tank 18 by an inlet conduit 16.

The engine 38 includes an inlet manifold 36.

The vapour collection apparatus in accordance with the invention includes a first fluid conduit 20, having an inlet end in communication with the inlet conduit 16 of the fuel tank, suitably at a point adjacent the inlet receptacle 14, and an outlet end communicating with a vapour collection chamber 28, which comprises a vacuum chamber. The first fluid conduit 20 incorporates a vacuum pump 22, one-way valve 24 (permitting fluid flow only in the direction from the inlet end to the outlet end of the conduit 16) and control valve 26. The apparatus further includes sensor means 12 associated with the fuel tank inlet receptacle 14 and a system management unit 10. The management unit 10 controls the operation of the pump 22 and control valve 26, in response to signals from the sensor means 12. The apparatus preferably also includes a pressure sensor (pressure valve) 30 for sensing the pressure within the collection chamber 28. The pressure sensor 30 is also connected to the management unit 10.

The sensor means 12 may be of any type suitable for detecting, for example, the insertion of a fuel dispensing nozzle into the inlet receptacle 14 or the removal of a closure cap (not shown) from the receptacle. The sensor may thus be a simple switch (e.g. an optical switch for detecting insertion of a dispensing nozzle) which, when operated, provides a signal to the management unit 10 to activate or deactivate the vapour recovery system. Alternatively or additionally, the sensor means 12 may comprise or include a hydrocarbon sensor for detecting the presence of hydrocarbon vapours in the inlet 14 or at another appropriate location.

When the management unit 10 receives a signal indicating that it should activate the vapour collection system, it opens the control valve 26 and switches on the pump 22, so that fuel vapour is drawn from the fuel tank inlet conduit 16, through the first conduit 20 and into the collection chamber 28. The one-way valve 24 prevents any fluid transport in the opposite direction. When the management unit 10 receives a signal indicating that it should de-activate the vapour collection system, it switches off the pump 22 and closes the control valve 26 so that the collected fuel is contained within the collection chamber 28. The system may be programmed such that vapour collection continues for a period after the deactivation signal is received by the management unit 10.

The vacuum chamber 28 is preferably of a lightweight construction such as a suitable metal or plastics material. The vacuum chamber 28 might suitably be rated at a pressure of between 5 and 10 pounds-persquare-inch, although this rating and also the associated volume may be varied and both very much depend upon the size of vehicle in which the apparatus is installed and also on the size of fuel tank 18 and the type of fuel. In the event that the pressure sensor 30 detects excessive pressure in the vacuum chamber 28 during the collection of vapours, the system will be de-activated, allowing vapour to be released into the atmosphere.

The fuel collected in the vacuum chamber 18 can be dealt with in a number of ways. For example, the chamber might be manually drained periodically.

However, this would clearly be inconvenient and undesirable. Alternatively, the collected fuel might be fed back to the fuel tank. In the preferred embodiment, as illustrated, the apparatus is further adapted to deliver the collected fuel to the engine 38 at appropriate times when the vehicle is in use. For this purpose, the system includes a second fluid conduit 42 having an inlet end communicating with the vacuum chamber 28 and an outlet end connected to the inlet manifold 36 of the engine 38, and incorporating a regulating valve 32 which is controlled by the management unit 10. Accordingly, the apparatus not only prevents the release of fuel vapour into the environment, but also re-cycles the recovered fuel.

Delivery of the collected fuel to the inlet manifold 36 is controlled by the management unit 10 and regulating valve 32 on the basis of predetermined criteria so as to avoid adverse effects on the operation of the engine and/or catalytic converter (if fitted, not shown) of the vehicle. The delivery system is de-activated when the apparatus is operating in vapour collection mode and is activated when said criteria are satisfied. The fuel delivery criteria may suitably be based on manifold pressure or engine temperature or engine speed or road speed or the pressure in the vacuum chamber, or on combinations of such parameters.

In the present example, a sensor 34, connected to the management unit 10, detects the manifold pressure. The operation of the regulating valve 32 is dependent on the manifold pressure and the vacuum chamber pressure, with the degree of opening of the regulating valve being determined primarily by the vacuum chamber pressure.

Typically, the regulating valve 32 will be opened upon the engine speed reaching a predetermined value such as 2500 revolutions-per-minute which, depending upon the size of engine and gearing ratio, is the equivalent of about 30 mph. The management unit 10 may include connections to existing sensor systems of the vehicle if required, and may be incorporated into the overall engine management systems of the vehicle.

Optionally, a filter such as an activated carbon filter 40 can be incorporated in the second conduit 42 downstream of the regulating valve 32 such that the fuel vapour is filtered before being delivered to the inlet manifold 36. Any such filter 40 should be incorporated in such a way as to be replaceable after the useful life of the filter 40 has expired.

Fig. 2 illustrates a preferred embodiment of the invention. This is substantially identical to that of Fig. 1, except that it includes a connection between the management unit 10 and a road speed sensor 46, and a temperature sensor 44 for sensing the engine temperature. Signals from these sensors representing the road speed and engine temperature are used along with signals representing the vacuum chamber pressure and the manifold pressure to control the operation of the regulating valve 32 in accordance with predetermined criteria as previously described.

When the vehicle is operating, the pressure sensor 30 and regulating valve 32 operate so as to prevent damage and premature wear of the catalytic converter of the engine. The manifold pressure sensor 34 operates to maintain correct idling speed so as to avoid any malfunction or erratic running whilst the engine is idling. The engine temperature sensor 44 prevents the system from operating to deliver recovered fuel to the engine when the engine has not reached its normal operating temperature, thereby preventing the catalytic converter from being poisoned when the engine is cold.

Finally, the road speed sensor 46 and manifold pressure sensor 34 prevent operation of the system unless the management unit receives appropriate signals from both sensors.

When all of the recovered fuel has been released from the vacuum chamber 28, the pressure sensor will signal the management unit to close the regulating valve 32, thereby resetting the system to function at the next re-fuelling operation.

Any toxic vapours from the vacuum chamber which are not burned by the engine will be rendered harmless by the catalytic converter of the vehicle.

The management unit 10 may be implemented using well known electronic control technology, as will be evident to those skilled in the art, and is not described in detail herein. The various valves, sensors, pump etc.

will be of types suitable for use with flammable and volatile fluids, as will also be apparent to those skilled in the art.

Modifications and improvements may be made to the foregoing within the scope of the present invention.

Claims

1. Fuel vapour collection apparatus for collecting fuel vapour released in the inlet of a vehicle fuel tank during re-fuelling, comprising: fluid conduit means having a first end communicating with said fuel tank inlet and an outlet communicating with a vapour collection chamber; control valve means and pump means located in said fluid conduit for controlling the flow of fluid therethrough; and control means for controlling the operation of said valve means and pump means.

2. Apparatus as claimed in Claim 1, wherein said control means includes sensor means adapted to generate a signal for controlling the operation of said valve means and pump means.

3. Apparatus as claimed in Claim 2, wherein said sensor means is adapted to detect the presence or absence of a fuel dispensing nozzle in said fuel tank inlet.

4. Apparatus as claimed in Claim 2 or Claim 3, wherein said sensor means includes means for detecting the presence of hydrocarbons in said fuel tank inlet.

5. Apparatus as claimed in any one of Claims 2 to 4, wherein said control means also includes a management unit connected to said sensor means, said control valve means and said pump means.

6. Apparatus as claimed in any preceding Claim, wherein said control valve means is located downstream of said pump means in the direction of fluid flow from said inlet to said collection chamber.

7. Apparatus as claimed in any preceding Claim, wherein the apparatus further includes one way valve means incorporated in said fluid conduit and adapted to prevent fluid flow in the upstream direction from said collection chamber to said inlet.

8. Apparatus as claimed in any preceding Claim, wherein said collection chamber also includes pressure sensing means for monitoring the fluid pressure inside said chamber.

9. Apparatus as claimed in Claim 8, wherein said pressure sensor is connected to the management unit of Claim 5.

10. Apparatus as claimed in any preceding Claim, further including second fluid conduit means, having an inlet communicating with said collection chamber and an outlet adapted for connection to an inlet manifold of the vehicle engine, and said control means is further adapted for controlling the flow of fluid from said chamber and through said second conduit.

11. Apparatus as claimed in Claim 10, wherein said control means further includes valve means incorporated in said second fluid conduit means.

12. Apparatus as claimed in Claim 10 or Claim 11, further including filter means such as an activated charcoal filter incorporated in said second conduit means.

13. Apparatus as claimed in any one of Claims 10 to 12, wherein the flow of fluid through said second conduit means is controlled by said control means on the basis of any appropriate criteria, such as collection chamber pressure, engine temperature, engine inlet manifold pressure, engine speed, or vehicle roadspeed, or combinations of these.

14. A vehicle equipped with a fuel vapour collection system in accordance with any one of Claims 1 to 13.