A secondary air system for an aircraft engine comprises an air flow path communicating between a source of pressurized cooling air and an air consuming component. A filter is disposed in the air flow path upstream from the air consuming component. The filter has at least one of: openings of a size selected for capturing suspended particles; and a filter surface material for binding with chemical contaminants.

A secondary air system for an aircraft engine comprises an air flow path communicating between a source of pressurized cooling air and an air consuming component. A filter is disposed in the air flow path upstream from the air consuming component. The filter has at least one of: openings of a size selected for capturing suspended particles; and a filter surface material for binding with chemical contaminants.

Methods and systems are provided for an engine having a pre-chamber ignition system. In one example, a method may include adjusting a valve coupled between a pre-chamber of an engine cylinder and a main chamber of the engine cylinder between a fully open position and a fully closed position based on whether pre-chamber ignition is desired or direct spark ignition is desired. In this way, the engine may be operated with direct spark ignition during conditions when pre-chamber combustion has reduced stability without including additional spark plugs and air injectors.

Methods and systems are provided for an engine having a pre-chamber ignition system. In one example, a method may include adjusting a valve coupled between a pre-chamber of an engine cylinder and a main chamber of the engine cylinder between a fully open position and a fully closed position based on whether pre-chamber ignition is desired or direct spark ignition is desired. In this way, the engine may be operated with direct spark ignition during conditions when pre-chamber combustion has reduced stability without including additional spark plugs and air injectors.

A secondary air system for an aircraft engine comprises an air flow path communicating between a source of pressurized cooling air and an air consuming component. A filter is disposed in the air flow path upstream from the air consuming component. The filter has at least one of: openings of a size selected for capturing suspended particles; and a filter surface material for binding with chemical contaminants.

A secondary air system for an aircraft engine comprises an air flow path communicating between a source of pressurized cooling air and an air consuming component. A filter is disposed in the air flow path upstream from the air consuming component. The filter has at least one of: openings of a size selected for capturing suspended particles; and a filter surface material for binding with chemical contaminants.

A method and fuel supply system for supply of a combustion chamber with at least one combustible fluid are provided. The fuel supply system includes a combustion chamber, at least one supply circuit, and at least one purge circuit, the purge circuit coupled to the at least one supply circuit, the purge circuit including at least two isolation valves defining a cavity between, a source of relatively high temperature purge air coupled in flow communication to the cavity through one of the at least two isolation valves, a source of relatively low temperature ventilation air coupled in flow communication to the cavity, and a vent coupled in flow communication to the cavity, the at least one purge circuit configured to channel a flow of relatively low temperature ventilation air from the source relatively low temperature ventilation air through the cavity to the vent during operation of the combustion chamber.

A method and fuel supply system for supply of a combustion chamber with at least one combustible fluid are provided. The fuel supply system includes a combustion chamber, at least one supply circuit, and at least one purge circuit, the purge circuit coupled to the at least one supply circuit, the purge circuit including at least two isolation valves defining a cavity between, a source of relatively high temperature purge air coupled in flow communication to the cavity through one of the at least two isolation valves, a source of relatively low temperature ventilation air coupled in flow communication to the cavity, and a vent coupled in flow communication to the cavity, the at least one purge circuit configured to channel a flow of relatively low temperature ventilation air from the source relatively low temperature ventilation air through the cavity to the vent during operation of the combustion chamber.

The invention relates a process for all internal combustion engines types to control the pressure and/or the temperature inside the combustion chamber at the time of ignition of combustion, despite that the air/fuel mixture is maintained close of stoichiometry ratio. It mainly based on high compression by an auxiliary compressor of air. This air is accumulated in a reservoir. The purpose is to have two sources of compressed air with a large gape of temperature, where one source is relatively cold and corresponding to the ambient environment, and the other source is relatively hot, heated by the heat energy recovered from exhaust gases. The intake compressed air is carried out with predetermined quantity from both sources as an injection into the cylinder which contains part of the burnt gases from the previous combustion cycle, kept with predetermined quantity. This is possible because the engine operates with a two-stroke cycle.

The invention relates a process for all internal combustion engines types to control the pressure and/or the temperature inside the combustion chamber at the time of ignition of combustion, despite that the air/fuel mixture is maintained close of stoichiometry ratio. It mainly based on high compression by an auxiliary compressor of air. This air is accumulated in a reservoir. The purpose is to have two sources of compressed air with a large gape of temperature, where one source is relatively cold and corresponding to the ambient environment, and the other source is relatively hot, heated by the heat energy recovered from exhaust gases. The intake compressed air is carried out with predetermined quantity from both sources as an injection into the cylinder which contains part of the burnt gases from the previous combustion cycle, kept with predetermined quantity. This is possible because the engine operates with a two-stroke cycle.