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 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 (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 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: 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 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: The ignition system (10) of an engine (particularly for a UAV) has a primary (10a), and a secondary (10b) ignition system to provide redundancy for ‘get you home’ capability should the primary ignition system fail. The secondary ignition provides a lower energy or shorter duration spark than the higher energy or longer duration sparking of the primary ignition system, and is retarded relative to primary sparking. Timing of the secondary sparking can be advanced in the event of primary sparking failure. Fuelling strategy can be shifted from a leaner stratified charge to a richer homogenous charge when relying just on the secondary ignition system for ignition. The secondary ignition system can be of a lower spark energy and/or duration than the primary ignition system, avoiding the cost, complexity and weight of replicating the primary ignition system, and to improve packaging within the engine housing, particularly within the limited payload and space limits of a UAV.

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 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: 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: The ignition system (10) of an engine (particularly for a UAV) has a primary (10a), and a secondary (10b) ignition system to provide redundancy for ‘get you home’ capability should the primary ignition system fail. The secondary ignition provides a lower energy or shorter duration spark than the higher energy or longer duration sparking of the primary ignition system, and is retarded relative to primary sparking. Timing of the secondary sparking can be advanced in the event of primary sparking failure. Fuelling strategy can be shifted from a leaner stratified charge to a richer homogenous charge when relying just on the secondary ignition system for ignition. The secondary ignition system can be of a lower spark energy and/or duration than the primary ignition system, avoiding the cost, complexity and weight of replicating the primary ignition system, and to improve packaging within the engine housing, particularly within the limited payload and space limits of a UAV.

Abstract: For an unmanned aerial vehicle (UAV) engine, an exhaust gas temperature control method is provided during operation of the UAV engine to protect exhaust components, particularly lightweight aluminium components, from overheating or melting. The engine is operated with a leaner than stoichiometric air-fuel ratio during low or part engine load conditions. Transition to a richer than stoichiometric air-fuel ratio is made as engine load or engine speed, or both engine load and engine speed, increase(s). At sufficiently low engine loads, the air-fuel ratio can be maintained in a lean ratio region. As demand on the engine causes engine speed and load to increase, the amount of excess air available reduces. The ability to operate lean is reduced and the exhaust gas temperature increases as the mixture becomes richer. In order to obtain the demand power, and keep exhaust temperature below an exhaust gas temperature limit, the air-fuel ratio is transitioned to a richer than stoichiometric region.

Abstract: A method of operation of a dual fluid fuel injection system arranged to supply fuel to a cylinder of an internal combustion engine, the dual fluid fuel injection system being controllable to effect fuel metering events and fuel delivery events. The method comprises operating the dual fluid fuel injection system so as to have at least one fuel delivery event during each engine cycle and to have fewer than one fuel metering event, on average, per engine cycle. An electronic control unit for implementing the method is also described. The method and control unit allow dynamic range of a fuel metering injector, where included within the dual fluid fuel injection system, to be extended.

Abstract: An unmanned aerial vehicle (UAV) engine (40) lubrication system and lubrication oil heating strategy uses a solenoid actuated electric oil pump (10,42) to deliver lubrication oil to the engine from a lubrication oil reservoir (12,44) by energizing and de-energizing the solenoid (18) to operate a pump mechanism of the electric oil pump. A controller (ECU) (100) can control operation of the electric oil pump, the solenoid maintained energized for a required period of time to cause heating of the oil without continuously pumping the oil. An electric oil pump control strategy can maintain engine speed dependent minimum oil delivery rates, can heat the electric oil pump and oil through extended energized (ON) time of the solenoid, and, by varying the turn on time of the electronic oil pump based on sensed ambient temperature, long time periods can be used to ensure oil delivery for cold temperatures, and shorter times are permitted when necessary in order to reach maximum oil flow rate.

Abstract: A fuel injector (10) for liquid phase injection of liquefied gaseous fuels for combustion chambers of an internal combustion engine. The fuel injector (10) comprises a nozzle portion (15) having an end (30) from which gaseous fuel can be delivered through an outlet (21), the end (30) being configured to prevent or at least inhibit formation of ice thereon upon delivery of gaseous fuel through the outlet.

Abstract: This disclosure describes a method of controlling operation of an unmanned aerial vehicle (UAV) having a flight control system comprising: a flight controller for implementing a flight control strategy; and an engine control unit interfaced with the flight controller for controlling engine operation. An engine speed target is set for the flight control system in response to one or more signals communicated by the flight controller to the engine control unit which controls engine operation to achieve the engine speed target by closed loop control over fueling without requiring throttle position control.

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 pressurisation system (17) for pressurising oil received by the pump from the reservoir for delivery to the engine. The pressurisation establishes a positive pressure at the pump inlet to assist delivery of oil having entrained vapour 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: For an unmanned aerial vehicle (UAV) engine, an exhaust gas temperature control method is provided during operation of the UAV engine to protect exhaust components, particularly lightweight aluminium components, from overheating or melting. The engine is operated with a leaner than stoichiometric air-fuel ratio during low or part engine load conditions. Transition to a richer than stoichiometric air-fuel ratio is made as engine load or engine speed, or both engine load and engine speed, increase(s). At sufficiently low engine loads, the air-fuel ratio can be maintained in a lean ratio region. As demand on the engine causes engine speed and load to increase, the amount of excess air available reduces. The ability to operate lean is reduced and the exhaust gas temperature increases as the mixture becomes richer. In order to obtain the demand power, and keep exhaust temperature below an exhaust gas temperature limit, the air-fuel ratio is transitioned to a richer than stoichiometric region.

Abstract: An unmanned aerial vehicle (UAV) engine (40) lubrication system and lubrication oil heating strategy uses a solenoid actuated electric oil pump (10,42) to deliver lubrication oil to the engine from a lubrication oil reservoir (12,44) by energising and de-energising the solenoid (18) to operate a pump mechanism of the electric oil pump. A controller (ECU) (100) can control operation of the electric oil pump, the solenoid maintained energised for a required period of time to cause heating of the oil without continuously pumping the oil. An electric oil pump control strategy can maintain engine speed dependent minimum oil delivery rates, can heat the electric oil pump and oil through extended energised (ON) time of the solenoid, and, by varying the turn on time of the electronic oil pump based on sensed ambient temperature, long time periods can be used to ensure oil delivery for cold temperatures, and shorter times are permitted when necessary in order to reach maximum oil flow rate.

Abstract: A method of controlling operation of an unmanned aerial vehicle having a flight control system (110) comprising: a flight controller (300) for implementing a flight control strategy; and an engine control unit (117) interfaced with said flight controller (300) for controlling engine (115) operation. An engine speed target is set for said flight control system in response to one or more signals communicated by said flight controller (300) to the engine control unit (117) which controls operation of engine (115) to achieve the engine speed target.