Engineers at Westport Innovations Corp.
used a unique one-dimensional simulation platform to model an
injection system that would allow diesel engines to run on
clean-burning natural gas.
Natural gas is in abundant supply and
prices have remained relatively stable for years-well below that of
diesel. Also, natural gas burns much cleaner with 33 percent less NOx
and 20 percent lower greenhouse gas emissions than equivalent
Converting a diesel engine to run on
natural gas is a tricky engineering problem. To provide enough power,
the flow of large amounts of the natural gas, in much greater volumes
than diesel fuel, must be carefully regulated and quickly delivered
to the cylinder at just the right time in the combustion cycle. To
complicate matters, natural gas requires a temperature of 800 degrees
to ignite, considerably higher than the easy-to-achieve 500 degrees
for burning diesel fuel.
Enter the liquid spark plug. Engineers
have overcome these technical roadblocks with an ingenious fuel
injector specifically designed for natural gas engines. At the heart
of the Westport HPDI (high-pressure direct injection) system is a
revolutionary injector tip assembly with dual-concentric needles. The
needles serve as little valves that open as they are lifted at just
the right time. This allows a small amount of diesel fuel to be
injected as an ignition source-sort of a "liquid spark
plug"-followed in a matter of milliseconds by large quantities of
natural gas sprayed at high pressure into the combustion chamber.
To gear up for the market's growing
demand for natural gas engines, Westport needed a more efficient
process for developing optimal injector designs much faster. With
this goal in mind, they investigated the LMS Imagine.Lab AMESim 1D