Mechanism for turbine engine start from low spool
First Claim
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1. A gas turbine engine, comprising:
- a high spool mechanically connected to a high spool bull gear;
a low spool mechanically connected to a fan and a low spool bull gear;
a gear system actuable to engage and disengage the low spool bull gear to and from the high spool bull gear with a bevel gear;
an actuator connected to the bevel gear for selectively engaging and disengaging the gear system; and
a motor/generator connected to the low spool, wherein the motor/generator is configured to control the rotational speed of the low spool bull gear to a point where the rotational speed of the low spool bull gear substantially matches the rotational speed of the high spool bull gear, wherein the actuator is controlled to engage the low spool bull gear and high spool bull gear by the bevel gear when the low spool bull gear and the high spool bull gear have the same rotational speed to allow rotation of the high spool to be driven by the motor/generator through the low spool.
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Abstract
A gas turbine engine includes a high spool, a low spool mechanically connected to a fan, a gear system, an actuator, and a starter. The gear system is actuable to engage and disengage the low spool to and from the high spool. The actuator is connected to the gear system for selectively engaging and disengaging the gear system. The starter is connected to the low spool and can drive rotation of the high spool through the low spool when the gear system is engaged.
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Citations
16 Claims
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1. A gas turbine engine, comprising:
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a high spool mechanically connected to a high spool bull gear; a low spool mechanically connected to a fan and a low spool bull gear; a gear system actuable to engage and disengage the low spool bull gear to and from the high spool bull gear with a bevel gear; an actuator connected to the bevel gear for selectively engaging and disengaging the gear system; and a motor/generator connected to the low spool, wherein the motor/generator is configured to control the rotational speed of the low spool bull gear to a point where the rotational speed of the low spool bull gear substantially matches the rotational speed of the high spool bull gear, wherein the actuator is controlled to engage the low spool bull gear and high spool bull gear by the bevel gear when the low spool bull gear and the high spool bull gear have the same rotational speed to allow rotation of the high spool to be driven by the motor/generator through the low spool. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of starting a gas turbine engine having a combustor, a high spool mechanically connected to a high spool bull gear, a low spool mechanically connected to a fan and a low spool bull gear, a gear system including a bevel gear capable of connecting the high spool bull gear and the low spool bull gear, and an actuator capable of engaging and disengaging the high spool bull gear and low spool bull gear, the method comprising:
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rotating the low spool and low spool bull gear via a starter that is configured to control the rotational speed of the low spool bull gear to substantially match the rotational speed of the high spool bull gear to allow the gear system to connect the low spool to the high spool by connecting the low spool bull gear and the high spool bull gear with the bevel gear; engaging the gear system with the actuator to connect the high spool bull gear to the low spool bull gear with the bevel gear so as to drive rotation of the high spool in response to rotation by the low spool; lighting the combustor; and disengaging the gear system such that the high spool can rotate independently from the low spool. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification