Aeronautics and astronautics – Aircraft power plants
Reexamination Certificate
2001-07-13
2003-04-22
Carone, Michael J. (Department: 3641)
Aeronautics and astronautics
Aircraft power plants
C060S288000, C244S062000
Reexamination Certificate
active
06550718
ABSTRACT:
BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE RELATED ART
The present invention relates to an aircraft engine and, in particular, to an aircraft engine capable of purifying the exhaust gas as needed according to the engine operating condition.
The exhaust gas from vehicles contributes to air pollution, and the permissible concentration values of air pollutants, such as hydrocarbon (CO) and nitrogen oxides (NOx) contained in the exhaust gas have been controlled by laws and regulations. To comply with these laws and regulations, exhaust gas purifying devices are mounted in vehicle engines.
Like vehicles, aircraft emit exhaust gas from their engines. However, this exhaust gas is under no legal control. Since the exhaust gas from aircraft at the time of preparing for takeoff and landing contributes to air pollution in the neighborhood of the airport, it is desirable that the exhaust gas from aircraft be purified like the exhaust gas from vehicles.
However, in aircraft, it is essential that a desired speed and altitude can be ensured in the air, and aircraft should be able to output a desired engine power. Providing an aircraft engine with an exhaust gas purifying device results in a reduction in engine power. Thus, no measures have been taken to purify the exhaust gas from aircraft engines.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide an aircraft engine which is capable of purifying the exhaust gas to thereby mitigate air pollution in the neighborhood of an airport and which can provide a desired engine power during flight.
Another object of the present invention is to provide an aircraft engine which involves no increase in aircraft weight and does not affect the flight condition and which is capable of mitigating air pollution in the neighborhood of an airport.
Still another object of the present invention is to provide an aircraft engine in which an engine control mechanism is appropriately controlled on the basis of information from a detection means for detecting the aircraft condition to thereby reduce the amount of pollutant in the exhaust gas and which is capable of providing a maximum engine output as needed.
To achieve the above objects, according to a first aspect of the present invention, there is provided an aircraft engine comprising an exhaust gas purifying device for purifying exhaust gas from the engine, and a switching means for switching the engine between an emission-emphasized mode in which the exhaust gas from the engine is purified by the exhaust gas purifying device and an output-emphasized mode in which emphasis is placed on engine output.
Thus, in the aircraft engine of the present invention, when the emission-emphasized mode is selected by the switching means, the exhaust gas from the engine is purified by the exhaust gas purifying device. When the output-emphasized mode is selected by the switching means, emphasis is placed on the engine output, and the engine is operated so that a maximum output can be achieved.
As a result, an aircraft engine is provided which can purify the exhaust gas from the engine to thereby prevent air pollution and which is capable of ensuring a desired engine output as needed.
According to a second aspect of the present invention, the switching means is controlled on the basis of detection results obtained by a detecting means for detecting whether the aircraft is in a pre-takeoff/post-landing state or a flight state. When the aircraft is in the pre-takeoff/post-landing state, the engine is operated in the emission-emphasized mode, and when the aircraft is in the flight state, the engine is operated in the output-emphasized mode.
Thus, according to the second aspect of the present invention, the detecting means detects the state of the aircraft, that is, detects whether the aircraft is in the pre-takeoff/post-landing state or the flight state to control the operation of the switching means.
Thus, according to the second aspect of the present invention, when the aircraft is in the pre-takeoff/post-landing state, the engine is operated in the emission-emphasized mode, and when the aircraft is in the flight state, the engine is operated in the output-emphasized mode.
According to a third aspect of the invention, the detecting means detects whether the aircraft is at rest on the ground with the engine operating, or the aircraft is moving on the ground at low speed, or the aircraft is flying. When the detecting means detects that the aircraft is at rest on the ground with the engine operating, or it is moving on the ground at low speed, the engine is operated in the emission-emphasized mode. When the detecting means detects that the aircraft is flying, the engine operation is switched to the output-emphasized mode.
Thus, in the third aspect of the present invention, the detecting means detects whether the aircraft is at rest on the ground, with the engine running at idle, or it is moving at, for example, an airport to a predetermined runway, that is, performing so-called taxying, or it is flying. When the aircraft is at rest on the ground, with the engine running at idle, or it is moving at, for example, an airport to a predetermined runway, that is, performing so-called taxying, the engine is operated in the emission-emphasized mode. When the detecting means detects that the aircraft is flying, the engine is operated in the output-emphasized mode.
Thus, according to the third aspect of the present invention, when no great engine power is required and it is necessary to prevent air pollution in the neighborhood as in the case in which the aircraft is at rest on the ground, with the engine running at idle, or performing taxying or the like, the switching means is controlled on the basis of the detection results obtained by the detecting means so as to operate the engine in the emission-emphasized mode.
On the other hand, when a predetermined great engine output is required as in the case in which the aircraft is starting to fly and taxying, or rising to a predetermined altitude, or cruising at the predetermined altitude or the like, the detecting means detects it, and controls the switching means accordingly so that the engine may be operated in the output-emphasized mode. Thus, it is possible to obtain a desired great engine output whenever it is required, so that the flight is not adversely affected.
According to a fourth aspect of the present invention, the exhaust gas purifying device is provided so as to be branched off from a first exhaust passage for discharging the exhaust gas to the exterior of the aircraft, and has a second exhaust passage for discharging the exhaust gas to the exterior of the aircraft and an exhaust purifying catalyst provided in the second exhaust passage.
Thus, in the fourth aspect of the present invention, when the engine exhaust gas is purified in the emission-emphasized mode, the exhaust gas flows into the second exhaust passage to be purified by the exhaust purifying catalyst before it is discharged to the exterior of the aircraft.
As a result, in the fourth aspect of the present invention, the exhaust gas discharged from the aircraft engine is purified by the exhaust purifying catalyst provided in the exhaust passage.
According to a fifth aspect of the present invention, the switching means is provided at the branch point between the first exhaust passage for discharging the exhaust gas to the exterior of the aircraft and the second exhaust passage having the exhaust purifying catalyst and adapted to discharge the exhaust gas after purifying it, and is formed by an exhaust passage switching means capable of introducing the exhaust from the engine into the first exhaust passage or the second exhaust passage.
Thus, in the fifth aspect of the present invention, the switching means is operation-controlled to change its position on the basis of the detection result obtained by the detecting means, thereby causing the exhaust gas from the engine to flow into the first exhaust passage or the second exhaust passage.
As a result, in the fifth aspect of the p
Carone Michael J.
Oliff & Berridg,e PLC
Semunegus Lulit
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