Woodward GECO, Техническое руководство, Страница: 26 / 90

GECO

Stoichiometric Manual 03554
18 Woodward
Fuel Control Valve for Full-flow Applications
In Full-flow fuel applications, the
GECO

Stoichiometric system controls
the air/fuel ratio by restricting the fuel to
the carburetor. The GECO system
adjusts this restriction using the L-series
‘Smart-Valve’ to vary the pressure input
to the carburetor that is adjusted slightly
rich. The GECO sends a low-current
PWM signal to the L-Series, which uses
an integrated driver to position its
butterfly valve. The valve flow is
proportional to the duty cycle command signal. The L-series needs a separate
10–32 V power supply to power its onboard driver circuitry. Different L-Series
models are available in five sizes ranging from 25–50 mm and also to open or
close the valve upon loss of power. The L-Series valve is configured to operate
with the GECO out of the box, and a PC Service Tool is included to configure the
valve for additional fault and positioning features. Fuel supply pressure to the
valve can be 0–30 psia. This valve is placed in between the final cut regulator
and the carburetor fuel inlet.
Connector
The following Deutsch connector components are recommended for harness
designs:
Recommended Optional
Mating Connector DT06-12SA-P012 DT06-12SA
Secondary Lock W12S-P012 N/A
Sockets 0462-201-16141 0462-201-16141
Woodward part number 8928-396 is a kit that provides all the necessary Deutsch
components.
Command
The position command from the GECO control is a 500 Hz, 0–24 V, pulse-width-
modulated signal (PWM).
Manual
Please refer to Woodward manual 26237 for more detailed information.
Environmental Specifications
Temperature: –40 to +105 °C (–40 to +221 °F)
Oxygen Sensors
The GECO  Stoichiometric system uses inexpensive, readily available automotive
exhaust gas oxygen sensors. The two-wire unheated sensor (EGO) upstream of
the catalyst is for air/fuel control feedback. A four-wire heated sensor (HEGO)
downstream of the catalyst provides adaptive control for engine, catalyst, and
fuel variations. The sensors are threaded for 18 mm x 1.5 ports, and high-
temperature anti-seize thread lubricant must be used to facilitate sensor
replacement.
Lubricants and sealants of any kind must be checked for oxygen sensor
compatibility
—even for use on the intake or crankcase ventilation system. Small
amounts of silicone and other contaminants can poison Zirconia-based sensors.