Segway FUGLEMAN SGW1000F-U2 Owner's Manual page 183

SOURCE OF EXHAUST EMISSIONS
The combustion process produces carbon monoxide (CO), oxides
of nitrogen (NOx) and hydrocarbons (HC). Control of hydrocarbons
and oxides of nitrogen is very important because, under certain
conditions, they react to form photochemical smog when
subjected to sunlight. Carbon monoxide does not react in the
same way, but it is toxic.
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system includes a PGM-F system
and oxygen sensor.
No adjustments to this system should be made although periodic
inspection of the components is recommended.
The exhaust emission control system is separate from the
crankcase emission control system.
CRANKCASE EMISSION CONTROL SYSTEM
The engine is equipped with a closed crankcase ventilation system
to prevent discharging the crankcase gases into the
atmosphere. Blow-by gases are returned to the combustion
chamber through the air filter box.
NOISE CONTROL SYSTEM
Do not modify the engine, air intake or exhaust components in
order to meet local noise level requirements.
171