Complete specification

Bypass air control mechanism for hybrid engine

Field of the invention and use of the invention:-

The present invention relates to hybrid jet engines and, more particularly, to turbofan and turbojet engine to control the air entering into bypass area.
The application of the hybrid jet engine can be used mainly in the fighter aircrafts.

Background of the invention:-

Gas turbine engines generally have in downstream flow relationship compressor, combustor, and turbine sections. The high and low turbines generally drive the high and low compressors and the low pressure turbine also drives the fan. The combustor bums fuel in an airflow compressed by the compressor to provide energy to the turbines. Gas turbine engines may have one, two, three, or more rotors or spools.

In the case of aircraft gas turbine engines, one or two fans upstream of the compressor are driven by one or two turbines as are the compressors. The fans, compressors, and turbines typically include radially extending blades. The function of the gas turbine engine is to provide high energy fluid, which can in turn be harnessed to provide power for a variety of applications.

Continuous axial flow gas turbine engines are utilized in a wide range of applications owing in a great deal to a combination of desirable attributes such as high specific energy exhaust stream (energy per unit mass), high mass flow rate for a given frontal area, continuous near steady fluid flow, and reasonable efficiency over a wide range of operating conditions. It is desirable to have light-weight and highly efficient engines. It is desirable to have gas turbine engines with as few parts as possible to reduce the costs of manufacturing, installing, refurbishing, overhauling, and replacing parts of the engine.

Various proposals have been made for dual-cycle propulsion systems which combine the features of the turbojet and turbofan engine concepts. One possible approach is the use of two virtually independent sets of engines with each set operating primarily only during the portion of the flight when its characteristics are most desirable.

In this method one set of engines is substantially unused at all times and as a result the total propulsion installation suffers a severe penalty in weight and bulk. A second approach is the use of a moderate to high bypass ratio turbofan with internal variable geometry features that permit a substantial reduction in bypass ratio for high-speed operation.

The disadvantages of this second approach are that the engine cycle cannot provide supersonic cruise efficiency as high as that for a pure turbojet and, at the same time, the supersonic drag of the installation is increased because the air inlet must be sized for low speed operation.

Prior Art and problem to be solved:-

No such closest prior art is available related to the present invention. However US4033119 is a method and apparatus applicable to jet engines for improving operating efficiency over broad ranges of flight conditions and for reducing engine noise output in take-off and landing. It incorporates variable configuration concepts which effectively vary the engine cycle from that of a turbojet for operation at high subsonic, transonic and supersonic speeds to that of a low bypass ratio turbofan for operation in the vicinity of the airport and at low flight speeds.

Another US patent No 5,826,424 describes a supersonic aircraft engine, either turbojet or turbofan, having a compressor, a diffuser, a combustion chamber, a turbine, and a nozzle passageway, and a turbine bypass passageway for bypassing compressor exit flow around the turbine. The bypass passageway comprises a plurality of supply pipes, and a flow control valve is mounted in each of the plurality of supply pipes. Under given flight conditions, a predetermined number of these flow control valves are fully closed, while the remaining flow control valves are opened as necessary for the given flight condition to obtain a desired rate of turbine bypass flow.

Another US patent No 7,624,565 is a hybrid worm gas turbine engine includes at least three gas turbine engine components including in downstream flow relationship a compressor, a combustor, and a turbine. At least one of the gas turbine engine components is a radially bladed component having at least one row of radially extending rotatable blades and at least one of the gas turbine engine components is a worm component. The worm component includes an inlet axially spaced apart and upstream from an outlet, an inner body disposed within an outer body, and the inner and outer bodies extending from the inlet to the outlet.

There are too many moving parts present for the above said patents. The inlet is not positioned linear which may create a lot of turbulence. The above utilizes two compressors thereby increasing weight. It's a Very complex design which is Difficult to maintain.

However the present invention relates to a gas turbine engine capable of dual operation as pure jet engine or bypass engine. Such engine requires a change over valve or a diversion which blocks the air from entering or passing through the bypass area. In this invention a set of latches are employed to carry out this diversion of air. As set of latches are arranged in annular fashion which move in synchronized manner when required.

Objective of the invention:-

The principal objective of the present invention is to divert the airflow entering into the bypass area.
Further objective of the present invention is to provide a latch mechanism to isolate airflow in the bypass area thereby switching the function of a bypass engine to turbojet engine.

Summary of the invention:-

A gas turbine engine is designed to operate as a turbofan at lower speeds and a turbojet when required. It consists of Hydraulic/Pneumatic system. Integrated circuits and Latches. A set of latches which are locked in one of two positions which is fully extended and fully retracted. The latch is attached to the outer wall of the bypass area and forms a part of the wall.

It is actuated using a hydraulic /pneumatic system and is regulated using an integrated circuit which gets its input from the tachometer. The control of the latches comes directly or indirectly from the cockpit. A set of latches are employed to carry out this diversion of air entering or passing through the bypass area.

The present invention is very less complex when compared to earlier attempts. Fuel efficient. Reduction in noise, extended range of the aircraft and Practical in all types of turbofan engines.

Detailed description of the invention with respect to diagram:-

The present invention blocks the air entering into bypass area through latch mechanism and allowing the air to enter in compressor.

The hydraulic fluid present in the reservoir tank (1) rushes with high pressure to the bypass control valve (2) which controls the flow of the highly pressurized hydraulic fluid. The fluid passes on to a pump(3) which pushes the fluid with a certain amount of force to the directional control valve (5) via the bypass fluid line, this directional control valve changes direction of the hydraulic fluid according to its operation. It either passes the major part of the fluid to the hydraulic cylinder (6) or it passes on the excess fluid to the return line filter (4) which sends back the fluid to the tank. The fluid sent to the hydraulic cylinder is compressed by the hydraulic pistons to move the connecting rod which further on rotates the hinge which deploys the set of latch(7). This latch deploys downward onto the inner core surface of the engine and automatically locks itself into place with the help of the simple locking mechanism (8).

A set of latches (7) are arranged in annular fashion which move in synchronized manner when required. These latches are arranged such that each latch is positioned at a small angle with respect to the neighbouring latch having an area of the latch overlapping the neighbouring latch. This overlapping area is positioned behind the neighboring latch which is attached to the inner core using normal door lock mechanism.

The latch is located on the inner surface of the cowl, so that no disturbance is present during the action of the engine as a turbofan at lower speed. The hydraulic system will have a piston assembly that will have a connecting rod having a hinge at its edge incorporating the latch. The piston shall receive hydraulic fluid (1) from the hydraulic system thus pushing the piston forward and backward, thereby turning the hinge which in turn retracts and deploys the latch. There is an additional two piston arrangement at a certain distance apart from the main hydraulic system; this is in order to ease the load on a single piston arrangement, thereby transmitting the work to the other piston arrangements with the assistance of hydraulic fluid lines.

The extension and retraction is controlled primarily by a pneumatic system and has a back-up of a hydraulic system. The hydraulic system also forms a part of the manual override in case of emergencies. These pneumatic /hydraulic actuators are attached to the
main frame of the engine cowling.

The extension and retraction is done either automatically or manually. The primary system is chosen as an automatic and is done using a set of integrated circuits and inputs from the tachometer and other instruments. The manual (secondary) system is controlled by the pilot in case of emergencies and/or high power requirements.

An IC741 comparator will be used for regulating the function of the hydraulic system, this 1C741 will be located in the avionics bay of the aircraft, which utilizing power from the aircraft will transmit its signals to the regulator which is further connected to the hydraulic system. The IC741 will receive its actuation from the aircraft cockpit through a set of aircraft bus signals. 1C741 comparator is given with a reference voltage. The reference voltage is calibrated according to the voltage received from the tacho- generator which in turn receives its input from the tachometer.

The latch generally is in fully retracted position for the lower values of RPM and thus enables the engine to perform as a bypass engine. As the value of RPM increases to some threshold value of around threshold rpm, the voltage generated by the tacho - generator reaches its own threshold value thus activating the pneumatic system. This extends the latches in unison thereby, effectively blocking the bypass area and diverting air into the compressor.

When extended, a locking mechanism (8) holds the latches in place relieving the load on the pneumatic system and thus effectively using the system for movement of the latches. This ensures the longevity of the pneumatic and hydraulic system and prevents loading of the system beyond its capability. When the value of RPM is lowered to blow the threshold RPM, the same system engages the retraction mechanism thus returning the engine configuration to the bypass type.

For the Locking mechanism (8) a simple door lock arrangement is placed on the outer casing of the inner core of the engine. The latch when deployed will lock itself onto the lock when initiated by the piston assembly. When it retracts it will unlock and rest on the inner region of the inner casing of the cowl.

Claims:-

I / we claim:

1. A gas turbine engine comprising,

a. Two hybrid engines (turbojet or turbofan engine)

b. pneumatic/ hydraulic actuators

c. Integrated circuits, IC741 and

d. latches

wherein the turbine engine operate as a turbofan at lower speeds and a turbojet when required; pneumatic/ hydraulic actuators are attached to the main frame of the engine cowling with the hydraulic reservoir present in the wing section; IC741 will be located in the avionics bay of the aircraft and latches are located on the inner surface of the cowl; whereby divert the airflow entering into the bypass area through latch mechanism.

2. A gas turbine engine is claimed in claim 1 further comprising a set of latches arranged in annular fashion such that each latch is positioned at a small angle with respect to the neighbouring latch having an area of the latch overlapping the neighbouring latch; this overlapping area is positioned behind the neighbouring latch which is attached to the inner core using normal door lock mechanism; which move in synchronized manner when required.

3. A gas turbine engine is claimed in claim 1 further comprising the extension and retraction is controlled primarily by a pneumatic system and has a back-up of a hydraulic system; the hydraulic system also forms a part of the manual override in case of emergencies; the extension and retraction is done either automatically or manually;

4. A gas turbine engine is claimed in claim 1 further comprising the primary system is chosen as automatic and is done using a set of integrated circuits and inputs from the
tachometer and other instruments ; the manual (secondary) system is controlled by the pilot in case of emergencies and/or high power requirements.

5. A gas turbine engine is claimed in claim 1 further comprising the 1C741 integrated circuits comparator with a given reference voltage; the reference voltage is calibrated according to the voltage received from the tacho-generator which in turn receives its input from the tachometer.

6. A gas turbine engine is claimed in claim 1 further comprising the latch generally is in fully retracted position for the lower values of RPM and thus enables the engine to perform as a bypass engine.

7. A gas turbine engine is claimed in claim 1 further comprising the value of RPM increases to some threshold value of around threshold rpm; the voltage generated by the tacho-generator reaches its own threshold value thus activating the hydraulic system.

8. A gas turbine engine is claimed in claim 1 further comprising the latches in unison thereby; effectively blocking the bypass area and diverting air to the compressor; when extended, a locking mechanism holds the latches in place relieving the load on the hydraulic system and thus effectively using the system for movement of the latches.

9. A gas turbine engine is claimed in claim 1 further comprising the latch is locked in place there is an immediate automatic increase in the fuel supply to the combustion chamber of the engine thereby maintaining the air/ fuel ratio; this ensures the longevity of the hydraulic system and prevents loading of the system beyond its capability.

10. A gas turbine engine is claimed in claim 1 further comprising the value of RPM is lowered to below the threshold RPM, the same system engages the retraction mechanism thus returning the engine configuration to the bypass type.