Electronic Throttle Body; Three Way Catalyst - Kubota WG1605-E3 Diagnostic Manual

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
ELECTRONIC THROTTLE BODY (ETB) (ALL)
The Kubota fuel systems utilize Drive By Wire
(DBW), to control engine speed, in this type of
application. There is no direct connection between the
operator pedal, and the throttle shaft. Speed and load
control are determined
programmed into the ECM software, and throttle position
sensors, allow the ECM, to maintain safe operating
control, over the engine.
In a drive by wire application, the Electronic Throttle
Body (ETB) device, or "throttle body assembly", is
connected to the intake manifold of the engine. The
electronic throttle control device, utilizes an electric
motor, connected to the throttle shaft. In addition, a Foot
Pedal Position sensor (FPP) is located in the operator's
compartment. When the engine is running, electrical
signals are sent from the foot pedal position sensor, to
the engine ECM, when the operator depresses or
release the foot pedal. The ECM then sends an electrical
signal to the motor, on the electronic throttle control, to
increase or decrease the angle of the throttle blade, thus
increasing or decreasing the air flow to the engine.
The electronic throttle
incorporates two internal Throttle Position Sensors
(TPS), which provide output signals to the ECM, as to
the location of the throttle shaft and blade. The TPS
information is used by the ECM, to correct for speed and
load control, as well as emission control, and engine
protection.
The ETB utilized on USA emission certified engines
do not require any periodic adjustment.
Figure 17: Electronic Throttle Body ETB
by the ECM. Defaults
control device also
THREE WAY CATALYST (ALL)
The emission certified engine has been designed
and calibrated, to meet the emission standards in effect
for 2010. To help meet the emission requirements, the
vehicle has been attached with a Three Way Catalyst
(TWC). Kubota has designed and supplied the catalyst
in a separate unit. The catalyst function is the final
treatment, of the exhaust gases, which are created from
the combustion process. The three-way catalyst consists
of a honeycomb, coated with a mixture of platinum,
palladium, and rhodium. As the hot gases flow through
the catalyst section, an oxidation and reduction reactions
takes place. This chemical reaction reduces the amount
of CO, HC and NOx, in the engines exhaust. The
Exhaust gas then flows through the outlet.
1-51
ECM SYSTEM
KiSC issued 12, 2016 A