| 摘要 |
An engine fuel control system includes a metering valve to control fuel flow between the supply and delivery line with a pressure drop control regulating the pressure across the valve and maintain a substantially constant pressure across the valve. The fuel control system includes a backup system controllable by a pullback signal to operate the pressure control, thus increasing the pullback signal reducing the fuel flow between the supply and delivery line. The fuel control system detects a start of an engine overthrust event, and when the upward runaway is caused by the arrested overthrust event. The fuel control system's controller which (i) determines the overthrust detection, the pullback signal increase rate and the pullback signal offset, (ii) sends the pullback signal to the backup system at the rate of increase, and (iii), reduces the pullback signal to the backup system when the upward runaway is arrested by the offset. |
| 主权项 |
1. An engine fuel control system including:
a fuel metering valve operable to control the flow of fuel between a supply line and a delivery line, a pressure drop control arrangement operable to regulate a pressure drop across the metering valve, the pressure drop control arrangement maintaining in normal use a substantially constant pressure drop across the metering valve, an electro-mechanical backup control system which, in the event of an engine overthrust event, is controllable by an electrical pullback signal to operate the pressure drop control arrangement, such that increasing the pullback signal reduces the flow of fuel between the supply line and the delivery line, a detector arrangement which detects a start of an engine overthrust event, and detects a time at which an upward runaway caused by the overthrust event is arrested, and a controller which (i) determines, at the time of the overthrust detection, a rate of increase of the pullback signal and an offset of the pullback signal, (ii) sends the pullback signal to the backup control system at the determined rate of increase, and (iii), when the upward runaway is arrested, reduces the pullback signal sent to the backup control system by the determined offset. |
