Based on the automotive DI development, Orbital has refined and
simplified the air assisted DI system for 4 stroke motorcycles,
with applications from 125cc per cylinder up to large displacement
engines.
The prime advantages offered by direct injection
are in both fuel economy improvement and emission control, especially
Oxides of Nitrogen and Carbon Monoxide. Performance levels can be
increased due to the ability to increase compression ratio and to
remove the typical cam timing constraints needed for satisfactory
idle and low load homogeneous operation with carburettors or Port
Injection.
The Orbital system's high tolerance of EGR
enables the OEM to significantly reduce the Oxides of Nitrogen without
sacrificing fuel economy by running rich, or stoichiometric for
use with TWC (Three Way Catalyst). This potentially enables oxidising-only
catalyst solutions for advanced emission requirements such as Euro
III.
Depending on the system specification, and
on the base engine capability, the Orbital system can be expected
to offer up to 20% or more fuel economy whilst achieving Euro III
level emissions.
