Cadillac GMS SIERRA Release Note - page 13
active fuel ManageMent By sensing load and demand, AFM
improves efficiency by activating or deactivating cylinders (two on the
V-6 and four on the V-8). Under high-demand conditions, such as at
high speeds or when loads demand more power, the valve’s switching
mechanism is depressurized, reengaging the cylinder and restoring full
power—without you ever noticing the transition.
direct injection For precise fuel distribution and fast, efficient
combustion, all engines benefit from DI technology. The system moves
the fuel closer to the ignition point in the engine—the combustion
chamber. By injecting fuel at over 2000 psi, the air and fuel mix more
completely. This helps the charge to burn fast for crisp throttle response
and maximum combustion efficiency at cruising speeds.
variable valve tiMing
For responsiveness in low-speed city
driving and bold power for open-road passing or trailering, all Sierra
engines feature continuous VVT. It monitors and adjusts valve open and
close points for near-peak levels of torque across the entire range of
engine speeds. A unique dual-equal phaser adjusts the camshaft timing
for both intake and exhaust valves.
17
The new plenum design delivers the precise balance of power and torque. This allows
Sierra’s engines to generate the low-end torque that you demand. Manifold geometry was
extensively analyzed to develop a robust combustion system for maximum performance.
A new composite intake manifold reduces mass and helps
thermally isolate air from under-hood heat. This improves
volumetric efficiency (power and torque) during hot conditions.
All engines utilize a deep-skirt cylinder block, enhanced
cooling system and newly designed cylinder heads. The
engines are engineered to accommodate an engine-driven
high-pressure fuel pump to optimize DI for outstanding
performance, efficiency and even reduced engine noise
for a quieter cabin.
An instantaneous response to driver inputs allows Electronic Throttle Control
to play a key role in optimizing DI, AFM and VVT. A sensor measures pedal
position, signaling the throttle to open at the precise rate and angle.
ecotec3 = More power with less energy, that’s our big bang theory.
EcoTec3 5.3L V-8 engine