General Motors will introduce a compact new DOHC 4.5-liter Duramax turbodiesel engine that
will be rated at least 310 hp and 520 lb-ft of torque, GM said, and will fit in the same
space as the small-block gasoline V-8. The 4.5 Duramax will be used in light-duty trucks
and Hummer’s H2.
GM said the new diesel “is expected to become a favorite among customers
who require excellent towing ability and fuel efficiency.” The engine, which will be
capable of running on some mix of biodiesel, is to feature selective catalytic-reduction
exhaust after-treatment, and a diesel particulate filter to pass 2010 diesel emission
standards and meet diesel regulations in all 50 states.
The 4.5L Duramax also will boost
efficiency by 25 percent, while cutting carbon-dioxide emissions by 13 percent and
nitrogen-oxide emissions by at least 90 percent. Production is expected in the fourth
quarter of 2009.