The invention relates to an apparatus and a method for delivering fluids in an atomised form. Preferred embodiments of the invention provide means for accurately controlling the timing of the delivery of atomised fluid and, in particular, the delivery of atomised fuel to an internal combustion engine.

It is known in the art to provide internal combustion engines such as those described in WO 2009/034342, the disclosure of which is fully incorporated herein by reference .

These internal combustion engines comprise: a variable volume combustion chamber; an air intake passage

supplying air to the combustion chamber; a throttle provided in the air intake passage for throttling flow of air through the air intake assage,- a bypass passage which bypasses the throttle and via which air and/or recirculated exhaust gas is supplied to the intake passage via a delivery outlet located downstream of the throttle; a fuel injector; and fuel and air mixing means comprising a bypass flow chamber connected to the bypass passage and a mixing chamber situated in the bypass flow chamber, wherein: the fuel injector delivers fuel to the mixing chamber; and the bypass passage is connected to the fuel and air mixing means so that air or recirculated exhaust gas flowing through the bypass passage passes through the mixing chamber means, entrains fuel present in the mixing chamber and a resulting mixture is

delivered from the mixing chamber means to the intake passage via the delivery outlet. The air or recirculated exhaust gas flowing through the bypass passage and passing through the mixing chamber means is induced by the depression formed in the air intake passage by the flow of air therethrough.

The inventor has discovered that when the engine is operating at full throttle (i.e. the throttle is fully open) the depression is not sufficient to draw air or recirculated exhaust gas through the bypass passage.

Since such engines use the flow of bypass gas as the entire means for entraining the fuel and delivering this to the cylinder, full throttle conditions may cause the engine to underperform.

The invention seeks to overcome such drawback by

presenting an engine in which fuel can be delivered irrespective of the throttle opening extent.

According to a first aspect of the invention there is provided an atomisation apparatus defined by claim 1.

This can be used in a preferred embodiment of an

atomisation system using a low pressure metered fuel supply and a low pressure air {or gas) supply.

It can be employed as port of the fuel injection system, in which case it may also include a high frequency valve to regulate and synchronise the air and fuel delivery with the engine cycle.

Preferred embodiments can use a pulse count injector (described in more detail below) to meter a pulsed supply of fluid/fuel into the fluid delivery tube. The fluid delivery tube would consist of a small diameter tube open at one end to admit the pulsed fluid/fuel supply and closed at the opposing end, but machined with a series of small diameter holes axially along its length to allow the fluid/fuel to exit.

The small series/array of a plurality of holes are preferably less than 0.2mm diameter can achieve a significant break-up and atomisation of the pulsed fluid/fuel and can direct the fluid into a desired direction upon exit from the tube.

Co-axially around the fluid delivery tube is provided a gas delivery tube that allows a metered or controlled flow of air/gas to surround the fluid delivery tube and has a narrow slit to allow the air/gas to exit the gas delivery tube aligned to coincide with the arrangement of small diameter fluid exit holes. The air/gas slit is sized to ensure the air/gas exiting the slit achieves a high velocity even with a low pressure supply (1 to 2 psi) , and this air/gas velocity imparts a high shearing force on the simultaneously exiting fluid/fuel generating a high degree of fluid atomisation.

Advantageously, this can achieve a very high degree of atomization of the fluid/fuel as the fluid is itself broken into a number of smaller streams by the multiple holes in the spray tube, which are then further easily atomised by the low pressure (but high velocity) air/gas passing through the co-aligned slit. This achieves a very high level of atomisation efficiency with very low energy fluid inputs.

Furthermore, even if the air/gas is not present for any reason the fluid is still directed in the desired direction and partially atomised by the small holes in the spray tube, making the system ideal in applications where the gas supply could be variable.

According to a second aspect of the invention there is provided an internal combustion engine defined by claim 9.

In a preferred embodiment, the above described

atomisation apparatus can be used for fuel injection into an intake port/throttle body of an internal combustion engine .

Fuel is metered and delivered by a fuel injector or control valve. This can be any fuel metering system but is ideally suited to a pulse count injector using a low cost fuel metering system. The fuel should ideally be timed sequentially with the induction stroke of the internal combustion engine (either 2 or 4 stroke

engines) . The correct amount of fuel required by the engine operational condition should be delivered by the fuel metering system, and synchronised to the engine induction phase of each engine cycle.

A separate control valve or metering orifice is fitted to the throttle bypass system that allows a controlled amount of air to bypass the throttle blade in the throttle body. This controlled air is drawn through the air slit during the induction stroke by the pressure drop created in the intake port during the intake stroke of the engine (when the throttle blade is in a partially closed condition) . Since the air and fuel synchronised together a fine fuel atomisation can be achieved that results in reduced emissions and lower fuel consumption of the engine.

Advantageously, since the atomisation apparatus of the first aspect is employed in this exemplary internal combustion engine, even in wide-open-throttle operation of the engine, when only a small depression exists in the induction port, very little air will be drawn through the air slit but the partially atomised fuel from the spray tube can still be delivered into the engine.

In further preferred embodiments, the air/gas valve is timed to be synchronous with the depression in the intake port. The duration of the air/gas valve opening is controlled by the controller to ensure correct air/gas flow for the operating condition of the engine. For a single cylinder engine this will be just for the one cylinder for a mul cylinder engine this duration can be individually timed for each cylinder to ensure best or equal air/gas flow into each cylinder individually.

The delivery of the fuel is also timed synchronously with the engine cycle to deliver the fuel into the intake port at the same time as the air/gas is flowing to ensure maximum atomisation of the fuel.

Such embodiments provide good control of air/gas flow so that fuel can be delivered at just the best time during the engine cycle.

Delivery of fuel and air can be optimised for each individual cylinder to achieve a better balance between cylinders . According to a third aspect of the invention there is provided a control valve as defined by claim 14.

In preferred embodiments, the piston is drawn away from the end face containing the inlet and outlet passages using a solenoid and spring arrangement, this allows gas to flow under light pressure from the inlet passages to the outlet passages. When the piston is returned to the closed position, the inlet and outlet passages are both sealed by the piston end- face.

This gas valve can react quickly and therefore can be driven by a high frequency signal. In combination with high frequency fluid delivery a very well controlled and efficient use of both gas and fluid can be achieved.

According to a fourth aspect of the invention there is provided a fuel injection system defined by claim 17.

According to a fifth aspect of the invention there is provided a fluid dispenser defined by claim...

In a preferred embodiment, the atomisation apparatus of the first aspect is used in a fluid atomisation system for delivering finely atomised spray into a domestic environment, for example household perfume spray or personal aerosol delivery.

Fluid is metered and delivered by a fluid injector or control valve, this can be any fluid metering system but is ideally suited to pulse count injector using a low cost fluid metering system. The fluid should ideally be timed sequentially with the delivery of air or gas passing through the air tube and slit. The correct amount of fluid required by the application can be delivered by the fluid metering system depending on either operator control or by electronic controller using sensor inputs to ensure the correct volume of fluid is metered.

A separate control valve or metering orifice is fitted to the air or gas delivery system which allows gas at a low pressure to pass through the tube and slit, creating a high velocity gas flow. With the air/gas and fluid synchronised together a fine fluid atomisation is achieved that results in more efficient fluid use and controlled delivery of finely atomised fluid.

The atomisation of the fluid is largely independent of air/gas pressure as long as a minimum gas flow is available making the system ideally suited to variable gas pressure supplies, e.g. a gas container which will gradually empty with use, and the fluid will still be delivered in a partially atomised form even when the gas pressure has completely decayed.

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a cross-sectional view of a first

embodiment of an atomisation apparatus in accordance with the invention;

Figure 2 shows a cross-sectional view of a fluid delivery conduit forming part of the first embodiment;

Figure 3 shows a cross-sectional view of a gas delivery conduit forming part of the first embodiment; Figure 4 shows a cross-sectional view of an air intake assembly for an internal combustion engine forming a second embodiment of the invention;

Figure 5 shows schematic representation of a valve for the internal combustion engine;

Figure 6a shows the valve end piece in cross-section; Figure 6b shows a side view of the valve end piece;

Figure 6c shows a perspective view of the valve end piece ;

Figure 7 shows a timing diagram representing the

preferred operation of the second embodiment; and

Figure 8 shows a cross-sectional view of an embodiment of an aerosol container forming an embodiment of the invention and having separate fluid and gas chambers with respective control valves and the atomisation apparatus of the first embodiment.

As shown in Figure 1, a first embodiment of an

atomisation apparatus comprises a fluid delivery tube 100 and a gas delivery tube 200.

The fluid delivery tube 100 is formed with one or more orifices 110 through which fluid can be ejected, and an opening 130 in an end of the tube into which fluid can be supplied. The end of the fluid delivery tube 100 opposite the opening 130 is closed.

Preferably, as shown in the figure, a plurality of orifices 110 are provided. These can be arranged in a line, a regular grid, or any other arrangement desired.

As shown in the figure, in this embodiment the orifices 110 are arranged in a row to achieve a narrow directed spray of fluid. The total area of the orifices 110 is preferably less than the area of the opening 130. Therefore, a large pressure is not required to produce a spray of fluid.

The orifices 110 are sized such that the supply of fluid under pressure will be atomised as it is expelled from the fluid delivery tube 100. Preferably, the orifices are circular in corss-section having a diameter of less than 0.2mm.

The gas delivery tube 200 is formed with a hole 210 through which gas can be delivered, a first opening 231 into which the fluid delivery tube 110 can be inserted, and a second opening 230 into which gas can be supplied.

The fluid delivery tube 100 is divided into a main portion 117, a narrow portion 115, and an end portion 119.

The narrow portion 115 of the fluid delivery tube 100 has a reduced width relative to the main body portion 117. The row of orifices 110 is formed in the narrow portion 115, so as to extend axially along the side of the fluid delivery tube 100.

The gas delivery tube 200 is sized to fit around a main portion 117 of the fluid delivery tube 100 to thereby prevent gas from exiting the first opening 231 of the gas delivery tube 200 (preferably, the gas delivery tube 200 tightly fits the fluid delivery tube 100) . Preferably, both the gas delivery tube 200 and the main portion 117 of the fluid delivery tube 100 are circular in cross- section . The gas delivery tube 200 is aligned with the first delivery tube 100, axially and rotationally such that the hole 210 is aligned with the plurality of orifices 110.

The hole 210 is larger than the area occupied by the orifices 110. Fluid delivered through the orifices 110 can therefore pass through the hole 210 without

obstruction .

The hole 210 is shaped to surround the area occupied by the orifices 110 (preferably, the hole 210 closely surrounds the orifices 110) . In the first embodiment the orifices 110 are arranged in a line, while the hole 210 forms a slot, surrounding the orifices 110.

The second opening 230 of the gas delivery tube 200 can be connected to a supply of pressurized gas, and/or gas can be drawn into the second opening 230 and through the gas delivery tube 200 by negative pressure at the hole 210.

In either case, a flow of gas into the second opening 230 through the gas delivery tube 200 and out of the hole 210 can be induced. This flow of gas will pass around the fluid delivery tube 100 in the region of the orifices 110 and interact with fluid when it is ejected from the orifices 110.

Although fluid forced through the orifices 110 in the fluid delivery tube 100 can be atomised merely by virtue of the sizing of the orifices 110, the flow of gas around the fluid delivery tube 100 will further atomise the fluid. More specifically, the gas flow as it leaves the gas delivery tube 200 through the hole 210 will increase in velocity. This high velocity gas flow atomises the delivered fluid by the shear forces applied between the flow of fluid and the gas flow. The atomisation effect provided by the gas flow is particularly effective because of the initial atomisation caused by the sizing of the orifices 110.

Advantageousl , since the gas flow produces an additional (and not the only) atomisation effect, in the event of an interruption of the gas flow, adequate atomisation still occurs .

The end portion 119 of the flow delivery tube 100 extends from the narrow portion 115 outwardly in the radial direction (i.e. in the direction perpendicular to the longitudinal axis of the flow delivery tube 100) over a region that is circumferentially aligned with the

orifices. The outward extension of che end portion 110 is thus a cover arranged to shield the spray of fluid leaving the orifices 110 to thereby prevent the direction of the spray from being diverted (relative to the

direction of the spray in the absence of any gas flow) . That is, in use, a spray of fluid leaving the orifices is shielded from a cross-flow of gas (i.e. gas flowing with a substantial component of flow perpendicular to the direction of the spray) .

Indeed, the end portion 119 and narrow portion 115 are shaped such that the flow of gas through the hole 210 is directed substantially in parallel with the flow of atomised fluid expelled from the fluid delivery tube 100. It can be seen from Figure 1 that in this preferred embodiment, fluid is supplied to the atomiser, at one end through the opening 130 in the fluid delivery tube 100, in a first axial direction and gas is delivered into the atomiser, at an opposite end through the opening 230 in the gas delivery tube 200, in a second axial direction, opposite to the first axial direction. Advantageously, such an atomiser can have a fluid delivery tube 100 having a width only slightly smaller than the width of the gas delivery tube. Thus, a compact atomiser can be provided .

In a second embodiment of the invention there is provided an internal combustion engine comprising: a combustion chamber; an air intake passage 310 for supplying air to the combustion chamber via an air intake valve; a throttle provided in the air intake passage 310 for throttling flow of air through the air intake passage 310; a fuel injection system 3U0, 330 arranged to deliver fuel to the combustion chamber via the air intake passage 310; a bypass passage 320 which bypasses the throttle and via which gas is supplied to the fuel injection system to entrain and/or atomise fuel delivered by the fuel injection system; and a control valve, arranged to open or close the bypass passage to thereby control the flow of gas therethrough.

Preferably, the control valve is a binary valve

(sometimes known as a bistable valve), that can only open and close. Such a valve does not allow any control of its degree of opening, i.e. it is not a metering valve.

Figure 4 shows an air intake assembly for use in the second embodiment, comprising an air intake passage 310, a fuel injection system 300, 330, and a bypass passage 320.

The bypass passage 320 is so called because it can introduce gas into the air intake passage 310 without it passing the throttle (not shown) , which is located upstream of the fuel injection system 300, 330.

The bypass passage 320 can, for example, carry fresh air, or recirculated exhaust gases to the fuel injection system 300 , 330.

As discussed below, the fuel injection system 300, 330, preferably incorporates the atomiser described above with reference to the first embodiment.

As can be seen in Figure 4, the air intake passage 310 includes a constriction 315 where the fuel injection system is located in order to generate a depression ( low- pressure region) as air moves along the air intake passage 310. Air will flow along the air intake passage 310 during the induction phase of the engine cycle.

Conventionally, gas will be drawn freely through a bypass passage as a result of the low pressure at the

constriction. This gas flow will vary in relation to the pressure change in the air intake passage over the whole engine cycle.

In the depicted embodiment, flow through the bypass passage 320 is controlled by a control valve 400 (not shown in Figure 4) operated by an electronic controller (not shown) . Therefore, low pressure in the air intake passage 310, will draw gas through the bypass passage 320 only when the control valve 400 is open.

Advantageously, the use of a control valve allows the gas flow along the bypass passage to be utilised to entrain and/or atomise fuel in the fuel injection system 300, 330, at chosen periods during the engine cycle. Such operation is discussed below with respect to Figure 6.

A preferable valve for use as control valve 400 is shown in Figure 5.

Since the control valve is used to control a low pressure gas flow it can be manufactured inexpensively. In preferred embodiments, the pressure of the gas flow through the bypass passage would be in the region of 1 to 2 psi .

The control valve 400 comprises a housing 420 in which a piston 410 can reciprocate along its axis. The housing 420 abuts an end piece 430.

The end piece 430 has an end face 440, which together with the housing 420 and the pressure face 412 of the piston 410 forms a piston chamber. The piston chamber varies on volume as the piston slides axially.

Preferably, the piston 410 is actuated by a solenoid. That is, the piston 410 is moved under the action of an electric coil. Specifically, a spring biases the piston to move in a first direction, while the force induced by the electric coil can overcome the spring force to move the piston 410 in a second direction. Preferably, the spring biases the valve to remain closed until a current is generated in the coil. Alternatively, a coil can be used to move the piston 410 in each direction.

The end piece 430 has a passage 441a and a passage 442a, formed therein which lead, respectively, to an inlet 441 and an outlet 442 formed in the end face 440.

The end piece 430 could be formed integrally with the housing 420, or they could be formed as separate

components .

Preferably, as shown in Figure 6, the inlet passage 441a is formed as an annular passage surrounding the outlet passage 441b. (Alternatively, the outlet passage 441b can surround the inlet passage 441a) .

The piston can slide axially such that its pressure face 412 can engage the end face 440 to thereby close both the inlet 441 and the outlet 442.

The passages 441a and 442a form part of the bypass passage 320. Therefore, movement of the piston 410 can open or close the bypass passage 320.

Advantageously, the piston 410 does not need to move a large distance to open or close the bypass passage 320. Furthermore, since the pressure of the flow through the bypass passage 320 is small, the forces applied to the piston by the spring or coil need not be great, and the piston can be extremely light.

Accordingly, such a control valve 400 can act with a very short response time and can be driven by a high frequency signal and thereby is suitable for opening and closing the bypass passage 320 at least once in each engine cycle. The control valve can operate at greater than 60Hz thereby allowing this functionality (i.e. the valve can open and close sixty times each second) . Indeed preferable embodiments of the control valve can operate at greater than 200 Hz and thereby allow fine control of the bypass gas. Operation of the control valve up to 1000Hz is desirable. Whilst other valves are known that can operate at this rate, the disclosed valve is

preferable .

Figure 7 shows a timing diagram representing the

preferred operation of the second embodiment.

Signal 710 represents the pressure in the air intake passage 310. This can be measured by a pressure sensor (not shown) and communicated to the electronic

controller .

Signal 720 represents the control signal produced by the electronic controller to dictate the state (open or closed) of the control valve 400. As can be seen in Figure 7, the control valve 400 is opened when the pressure measured by the sensor drops to a first

pressure, and the control valve 400 is closed when the pressure measured by the sensor rises to a second pressure .

Signal 730 represents the control signal produced by the electronic controller to dictate the delivery of fuel by a fuel injector. As will be described below, the fuel is preferably delivered using a pulse count injector that delivers multiple injections of equal volume. However, embodiments are envisaged in which the fuel is delivered using a standard fuel injector that continuously injects fuel for a period dictated by the control signal produced by the electronic controller.

In either case, and as can be seen in Figure 7, fuel is only delivered when the control valve 400 is open.

Advantageously, in a multi -cylinder engine the above described system can be provided for each cylinder and the timing of each control valve can be tailored to the individual cylinders. In such an engine, each control valve will open and close at least per cycle of the respective individual cylinder.

Whereas Figure 7 shows the timing as dictated by the pressure in the air intake passage 310, similar timing can be achieved by using a crankshaft position signal as the input to the controller instead of pressure. A particular point in the rotation ot the crankshaft will be representative of a point in the cyclical pressure signal. Thus, the control valve 400 can be opened when the crankshaft position signal represents a first point in the engine cycle, and the control valve 400 is closed when the crankshaft position signal represents a second point in the engine cycle.

In either case, the use of a signal representative of a position in the engine cycle allows the control valve 400 to open the bypass passage 320 for a period where the depression (low pressure) in the air intake passage 310 is greatest to optimise the timing of the delivery of the fuel and to close the bypass passage 320 at all other times . As briefly mentioned above, the fuel injection system can comprise a pulse count fuel injector system such as that disclosed in WO 2007/017627 and WO 2010/018377, the disclosures of which are fully incorporated herein by reference. In such a system, the fuel will be delivered in a series of injections from a positive displacement fuel injector that dispenses a fixed volume for each and every operation of the fuel injector.

The fuel injection system can be arranged such that the fuel injector delivers fuel into a fuel and gas mixing chamber formed as part of the bypass passage 320 such that that gas flowing through the bypass passage 320 passes through the mixing chamber, entrains fuel present in the mixing chamber and delivers the mixture into the air intake passage such as the fuel injection system disclosed in WO 2009/034342.

In preferred embodiments, however, the fuel injection system would comprise the atomiser of the first

embodiment. In such preferable embodiments, the bypass passage 320 communicates with the second opening of the gas delivery tube 200 so that the gas flowing along the bypass passage 320 can flow into the air intake passage 310 via the hole 210.

A fuel injector (for example a positive displacement fuel injector operating as part of a pulse count fuel

injection system as explained above) would deliver fuel via a passage 330 in communication with the opening 130 of a fluid delivery tube 100 so that fuel can be

delivered to the air intake passage 310 via orifices 110 formed in the fluid delivery tube 100. At full throttle conditions with low engine speeds, the depression formed in the air intake passage 310 is less strong than when the throttle is partly closed. As such, in full throttle conditions a relatively smaller gas flow will be drawn by the depression as compared with part- closed throttle conditions.

As explained above, the atomiser of the first embodiment is able to deliver an atomised spray of fuel even in the absence of gas flow through the gas delivery tube or when the gas flow is small. Advantageously, therefore, when such an atomiser is employed in the internal combustion engine of the second embodiment an adequate delivery of atomised fuel can be ensured even during full throttle conditions .

Furthermore, if the preferred arrangement of the atomiser of the first embodiment is used (i.e. the arrangement in which fluid is supplied to the atomiser in a first axial direction and gas is delivered into the atomiser in a second axial direction, opposite to the first axial direction) . Such a compact atomiser will provide only a small obstruction to the flow of intake air through the air intake passage 310.

Preferably the diameter of the orifices formed in the fluid delivery tube would be at most 0.2mm, in order to achieve sufficient atomisation. Such maximum size is particular beneficial for the delivery of fuels such as gasoline .

Figure 8 depicts a fluid dispenser forming a third embodiment of the invention. Embodiments are envisaged in which the fluid is a perfume, a medicine, or an air freshener. The atomiser of the first embodiment is used in the third embodiment to deliver fluid.

Preferably, as shown in Figure 8, the arrangement is used in which the gas and fluid are delivered from either end of the atomiser. Thereby the compact construction shown in Figure 8 is possible.

The gas delivery tube 200 is arranged to provide a supply of pressurised gas. Specifically, the opening 230 communicates with a pressurised gas reservoir 810, via a gas valve 812. The gas valve 812 may be electrically actuated or manually actuated as described below.

The fluid delivery tube 100 is arranged to provide a supply of fluid. Specifically, the opening 130

communicates with a fluid reservoir 800, via a fluid valve 802 (as shown in Figure 8) or a fluid injector such as a metered fluid injector (e.g. a pulse count

injector) . The fluid valve 802 or fluid injector, may be electrically actuated or manually actuated.

In embodiments in which the gas valve 812 and fluid valve 802 are manually actuated, the fluid dispenser can comprise a first housing part 820 and a second housing part 822, slidable relative to one another.

The fluid reservoir 800 and fluid valve 802 are held in the first housing part 820 and the gas reservoir 810 and gas valve 812 are is held in the second housing part 822. The atomiser is aligned with an opening in one of the housing parts 820, 822. The gas and fluid valves 802, 812 are held in the two housing parts 820, 822 such that when the two housing parts 820, 822 are slid toward each other, the valves 802, 812 are opened.

Since the atomiser is able to deliver atomised fluid without a flow of gas, such a fluid delivery tube can provide atomised fluid even when the gas pressure has dropped to low levels.

Preferably, the fluid reservoir 800 is interchangeable. Preferably, the gas reservoir 810 is interchangeable.

Preferably, the fluid valve 802 is configured and

arranged to provide a metered delivery of fluid. That is, a single actuation of the fluid valve 802 will dispense a fixed amount of fluid that is constant for every actuation of the fluid valve 802.

The fluid dispenser comprise electrically actuated valves 802, 812 or injectors. In such embodiments, the fluid dispenser comprises a power supply and a controller for controlling the electrically actuated valves 802, 812 or inj ectors .

Preferably, fluid will be provided to the fluid delivery tube 100 by a pulse count fluid injector, which delivers a fixed quantity of fluid for each and every injection operation. In which case, the quantity of fluid

delivered can be controlled by varying the number of injection operations.

Whereas in the first embodiment the fluid delivery tube and the gas delivery tube are cylindrical, coaxial, and tightly fitting, such an arrangement is not essential. Nor is it essential to deliver fluid or gas

perpendicularly from the longitudinal axis of the

delivery tubes.

Indeed, embodiments are envisaged in which the gas delivery tube is sized to surround the fluid delivery tube with a space therebetween. This space forms the path along which gas can flow, along the outside of the fluid delivery tube. The fluid delivery tube has a closed end face in which the orifices are formed. The gas delivery tube has a closed end face in which a hole is formed, aligned with the orifices of the fluid

delivery tube. Fluid is ejected and atomised through the orifices in the end face of the fluid delivery tube. The gas flowing along the outside of the fluid delivery tube can exit the gas delivery tube via the hole to further atomise the fluid exiting the fluid delivery tube.

Whereas in the internal combustion engine of the second embodiment gas is drawn into the bypass passage under action of a depression in the air intake passage, alternative embodiments are envisaged in which gas is supplied under positive pressure (i.e. the source

pressure is greater that the pressure in the air intake passage) . Such positive gas supply can be controlled by the control valve disclosed above.

Embodiments are envisaged in which the atomiser apparatus disclosed delivers one or more of: fuel; perfume;

agricultural spray; pesticides; plant food; water; paint; oil; corrosion preventative; emulsifier; fire

suppressant; air freshener; or medicine.