Abstract: A muffler (40) devised particularly for use with an engine of the type used on unmanned aerial vehicles (UAVs), and a UAV (10) having an engine (30) fitted with the muffler (40). The muffler (40) comprises a body (51) having an interior chamber (60). The muffler body (51) has a first end section (53) and a second end section (55). The first end section (51) is adapted for mounting onto the engine (31) by way of a first mount (81), with the interior chamber (60) in communication with an exhaust outlet of the engine (31) to receive exhaust flow therefrom. The second end section (53) is adapted to be mounted by way of a second mount (82) in a manner resisting movement with respect to the engine (31). In one arrangement, the second mount (82) is configured to yieldingly resist movement with respect to the engine (30). In another arrangement, the second mount (82) is configured to mount the second end section (55) under a preload resisting movement of the second end section with respect to the engine (30).

Abstract: A dual-fluid injection system for an internal combustion engine, and an unmanned aerial vehicle (UAV) powered by an engine having the dual-fluid injection system. The dual-fluid injection system comprises a liquid fuel metering device and a fluid delivery device operating in tandem. A gas supply system comprising an air compressor and an air delivery path extending between the air compressor and the fluid delivery device is provided to supply pressurised air to the fluid delivery device. The gas supply system comprises an air compressor and an air delivery path extending between the air compressor and the fluid delivery device. A fuel supply system is adapted to deliver liquid fuel to the liquid fuel metering device. A fuel-air regulator is provided for regulating fuel pressure with reference to air pressure to establish and maintain a requisite pressure differential between the fuel pressure and the air pressure.

Abstract: A compact muffler (40) for an engine exhaust system, which is particularly applicable for use with small, reciprocating piston two-stroke engines of the type used on unmanned aerial vehicles (UAVs). The compact muffler (40) comprises an exhaust gas flow path (67) between an inlet (61) and an outlet (63). The exhaust gas flow path (67) comprises a plurality of adjacent flow passages (65), wherein at least two of the adjacent flow passages (65) are fluidly connected in series to enable the flow of exhaust gas from one to the other along the flow path (67). The adjacent flow passages (65) are configured for fluid flow therealong in opposed directions. A bypass passage (70) is provided between the two adjacent flow passages (65) for further communication between the two flow passages and to promote an equalisation of fluid pressure within the two adjacent passages (65). A UAV having an internal combustion engine (31) fitted with an exhaust system comprising the compact muffler (40) is also disclosed.

Abstract: A muffler (40) devised particularly for use with an engine of the type used on unmanned aerial vehicles (UAVs), and a UAV (10) having an engine (30) fitted with the muffler (40). The muffler (40) comprises a body (51) having an interior chamber (60). The muffler body (51) has a first end section (53) and a second end section (55). The first end section (51) is adapted for mounting onto the engine (31) by way of a first mount (81), with the interior chamber (60) in communication with an exhaust outlet of the engine (31) to receive exhaust flow therefrom. The second end section (53) is adapted to be mounted by way of a second mount (82) in a manner resisting movement with respect to the engine (31). In one arrangement, the second mount (82) is configured to yieldingly resist movement with respect to the engine (30). In another arrangement, the second mount (82) is configured to mount the second end section (55) under a preload resisting movement of the second end section with respect to the engine (30).

Abstract: Disclosed is a method of controlling an internal combustion engine (102) of a UAV (100), and also disclosed is a UAV engine system (101), The engine (102) has a fuel delivery means (123) operable to deliver a fuel to a combustion chamber of the engine, and an air flow control means (107) for regulating air flow to the combustion chamber. The method comprises controlling the engine (102) through control of fuelling by way of the fuel delivery means (123) independently of the air flow control means (107), including determining a fuelling requirement for the engine based on a request from a flight control system, and determining an air flow requirement based on or with reference to the fuelling requirement. This provides for fuel-led control of the engine system (101). Specifically, a fuelling requirement for the engine (102) is determined and implemented, and the corresponding air requirement is then determined contingent upon the fuelling requirement.

Abstract: A control system and method relating to operation of an internal combustion engine, particularly an engine for powering an unmanned aerial vehicle. The engine has a combustion chamber and a throttle for regulating fluid flow to the combustion chamber, the throttle being operable under the control of an electronic control unit. With the control system and method there are first and second modes optionally available for operation of the engine. In the first mode the engine is operable at a throttle setting set by a request from a first remote controller (e.g. a ground-based controller) via a second on-board controller. In the second mode the engine is operable at a prescribed minimum throttle setting asserted by the electronic control unit which limits the authority of the on-board controller. The engine is caused to operate in the second mode if a particular throttle setting determined from a request of the remote controller is less than the prescribed minimum throttle setting.

Abstract: A method and system for controlling operation of an internal combustion engine of a vehicle (such as a remotely operable unmanned aerial vehicle) to perform or implement a control strategy for controlling operation of the engine. The method and system comprises providing first and second modes optionally available for operating the engine, and changing operation of the engine from the first mode of operation to the second mode of operation following a determination that a characteristic of the operation of the engine (such as engine speed) has been requested to be modified to beyond a predetermined threshold or level. The method and system further comprises reverting control of operation of the engine from the second mode to the first mode once the requested characteristic is no longer beyond the predetermined threshold or level.

Abstract: A method of operating an internal combustion engine system having a fuel injection system including a fluid delivery means operable to deliver a fuel entrained in gas directly into a combustion chamber. The method comprises supplying pressurised gas to the fluid delivery means from a gas supply system, and regulating gas pressure in the gas supply system. The gas pressure in the gas supply system may be regulated during a lag period between commencement of engine cranking and the delivery of fuel at a requisite fuel pressure to the fuel injection system. Regulating gas pressure in the gas supply system comprises opening the fluid delivery means to selectively allow gas to pass into the combustion chamber to relieve pressure in the gas supply system. Optionally, regulating gas pressure in the gas supply system may also comprise opening the fluid delivery means to selectively allow pressurised gas to flow from the combustion chamber to the gas supply system so as to pressurise the gas supply system.

Abstract: A method of operating an internal combustion engine system having a fuel injection system including a fluid delivery means operable to deliver a fuel entrained in gas directly into a combustion chamber. The method comprises supplying pressurised gas to the fluid delivery means from a gas supply system, and regulating gas pressure in the gas supply system. The gas pressure in the gas supply system may be regulated during a lag period between commencement of engine cranking and the delivery of fuel at a requisite fuel pressure to the fuel injection system. Regulating gas pressure in the gas supply system comprises opening the fluid delivery means to selectively allow gas to pass into the combustion chamber to relieve pressure in the gas supply system. Optionally, regulating gas pressure in the gas supply system may also comprise opening the fluid delivery means to selectively allow pressurised gas to flow from the combustion chamber to the gas supply system so as to pressurise the gas supply system.

Abstract: An unmanned aerial vehicle has an internal combustion engine, and a fuel and lubrication system comprising a fuelling system for fuelling the engine and a lubrication system for delivering lubricating oil to the engine. The fuelling system comprises a fuel reservoir from which fuel can be delivered to the engine. The fuel reservoir comprises a main tank and a header tank. The lubrication system comprises an oil tank. The oil tank is accommodated internally within the main tank to provide an integrated assembly. The arrangement provides for warming of lubrication oil for the UAV engine using several available heat sources. Further, the arrangement facilitates a configuration and layout intended to minimise or negate any undesirable moments of inertia for the UAV during flight as fuel and oil is consumed.

Abstract: A muffler devised particularly for a small, reciprocating-piston two-stroke internal combustion engine of the type used on unmanned aerial vehicles. The muffler comprises a body incorporating an inlet, an outlet, and a plurality of chambers for exhaust gas flow from the inlet to the outlet. The body is configured to present a compact profile for installation on the engine. The chambers are so configured that adjacent chambers communicate to facilitate exhaust gas flow from the inlet to the outlet via flow passages. The various chambers comprise an inner chamber, an outer chamber, and one or more intervening chambers disposed between the inner and outer chambers. The various chambers are disposed one about another in annular formation. This arrangement creates a long flow path from the inlet to the outlet incorporating various directional changes.

Abstract: Redundancy in engine timing position sensing maintains a UAV operational in the event of failure of a primary engine timing position sub-system. The redundancy avoids duplication of the primary crankshaft timing position sensing components, and avoids adding weight, cost and component complexity. Conditioned (square) waveform(s) (102) is/are created from respective sinusoidal waveform(s). Each consecutive leading edge (103a) and trailing edge (103b) of the pulses of the square waveform (102) is derived from the crossing of the zero voltage value by consecutive sinusoidal waveforms A,B,C (e.g. Voltage (V) vs Time (t) or angular degrees). The square pulse waveform (102) is output (104) to a microcontroller (106) to create and output a pseudo crankshaft timing position signal (108) to be used by an ECU to determine ignition and fuel injection events in the event that the primary timing signal from the crankshaft position sensor (CPS) has failed.

Abstract: A dual fluid injection system which comprises a liquid fuel metering device, a fluid delivery device, and apparatus providing an interface therebetween. The interface conveys liquid fuel along a flow path from the metering device to a mixing zone for mixing with air from a pressurized supply to provide an air-fuel mixture for injection by the fluid delivery device into a combustion chamber of an internal combustion engine. The flow path may involve a directional change by way of a turn section. The flow path is sized such that liquid fuel is retained therein by virtue of capillary action, whereby a quantity of liquid fuel is retained after a delivery event such that the flow path remains substantially filled with liquid fuel in readiness for the next delivery event during operation of the engine.

Abstract: A muffler devised particularly for a small, reciprocating-piston two-stroke internal combustion engine of the type used on unmanned aerial vehicles. The muffler comprises a body incorporating an inlet, an outlet, and a plurality of chambers for exhaust gas flow from the inlet to the outlet. The body is configured to present a compact profile for installation on the engine. The chambers are so configured that adjacent chambers communicate to facilitate exhaust gas flow from the inlet to the outlet via flow passages. The various chambers comprise an inner chamber, an outer chamber, and one or more intervening chambers disposed between the inner and outer chambers. The various chambers are disposed one about another in annular formation. This arrangement creates a long flow path from the inlet to the outlet incorporating various directional changes.

Abstract: A system and method for delivering lubrication oil to an internal combustion engine. The engine lubrication system (10) comprises a lubrication oil reservoir (13), a pump (15) to deliver lubrication oil to the engine from the reservoir (13), and a pressurization system (17) for pressurizing oil received by the pump from the reservoir for delivery to the engine. The pressurization establishes a positive pressure at the pump inlet to assist delivery of oil having entrained vapor cavities to the engine for lubrication thereof. The pump (15) comprises a solenoid actuated positive displacement pump, whereby operation of the pump may be selectively controlled by the manner in which the solenoid is operated. The engine lubrication system (10) further comprises a pressure release system (46) comprising pressure relief valve (47) for relieving excess fluid pressure within the oil reservoir (13).

Abstract: A method for fuelling an internal combustion engine, and a fuel system (10) for delivering a variety of fuel types to the engine, with selected fuel types typically being chosen according to theft availability. The fuel system (10) can be configured to accommodate liquid fuels such as gasoline, ethanol or a blend thereof, and gaseous fuels such as CNG, LNG or LPG. The engine is configured to operate on any of the designated liquid fuels, and can switch between the liquid and gaseous fuels. The fuel system (10) includes a respective common delivery arrangement (11) for selectively delivering fuel into the combustion chamber of each cylinder of the engine. The common delivery arrangement (11) comprises at a fluid delivery device (12) and a liquid metering device (31) configured for operation in concert. The fluid delivery device (12) comprises a fluid delivery injector.

Abstract: A fuel injection system (10) for delivering metered amounts fuel into the combustion chamber or cylinder of an engine. The fuel delivered can selectively comprise a gaseous fuel, a liquid fuel or a fuel mixture comprising the gaseous fuel and the liquid fuel. When the fuel delivered comprises a mixture of the gaseous fuel and the liquid fuel, the quantity of liquid fuel comprises a metered quantity. The quantity of gaseous fuel also comprises a metered quantity, with the metering of the gaseous fuel being regulated by prediction. The injection event involves delivering the liquid fuel and the gaseous fuel, with the metering of the gaseous fuel delivered being adjusted to allow for the quantity of liquid fuel delivered with the gaseous fuel. The injection system (10) comprises a liquid fuel circuit (11) and a gaseous fuel circuit (13), both communicating with a fuel delivery injector (15) that delivers fuel to the combustion chamber.

Abstract: An unmanned aerial vehicle has an internal combustion engine, and a fuel and lubrication system comprising a fuelling system for fuelling the engine and a lubrication system for delivering lubricating oil to the engine. The fuelling system comprises a fuel reservoir from which fuel can be delivered to the engine. The fuel reservoir comprises a main tank and a header tank. The lubrication system comprises an oil tank. The oil tank is accommodated internally within the main tank to provide an integrated assembly. The arrangement provides for warming of lubrication oil for the UAV engine using several available heat sources. Further, the arrangement facilitates a configuration and layout intended to minimise or negate any undesirable moments of inertia for the UAV during flight as fuel and oil is consumed.

Abstract: A fuel injection assembly comprising a fuel injector (19) having an injection outlet (19) and a fuel rail (17) in which the fuel injector is adapted to be supported. The fuel injector (19) has a tip (37) having an end from which fuel issuing from the outlet of the fuel injector is discharged. The tip (37) is adapted for location in an injection port (21), the tip being of flexible construction to accommodate some misalignment between the fuel rail (17) and the injection port (21).

Abstract: A fuel rail assembly for direct injection of a gaseous fuel into an internal combustion engine comprises a fuel rail defining a flow passage for receiving gaseous fuel and a delivery injector for directly injecting fuel received from the fuel rail into a combustion chamber of the engine. The delivery injector is arranged having a selectively openable delivery port for delivery of gaseous fuel into the combustion chamber when the delivery port is in an open condition. The fuel rail assembly further comprises a valve operable so as to interrupt the flow of gaseous fuel to the delivery injector for delivery into the combustion chamber. A containment zone is defined between the valve and the delivery port when the delivery port is in a closed condition, whereby the containment zone is selected so as to be a prescribed volume.