http://world.honda.com/HDTV/news/2005-4050705a/
TOKYO, Japan, July 5, 2005 - Honda Motor Co., Ltd. today announced
that it has developed a new 1.8l i-VTEC engine to be introduced
this fall in the new Civic that achieves both more powerful
performance and improved fuel economy. The engine employs an
intelligent VTEC system that switches the valve timing for maximum
efficiency during startup and acceleration to achieve powerful,
torquey performance, then delays intake valve closure timing during
cruising and other low-load conditions for improved fuel economy.
Use of the valve timing control system results in off-the-line
acceleration performance equivalent to a 2.0-liter engine, fuel
economy approximately 6% better than the current 1.7-liter Civic
engine, making it one of the worlds most efficient 1.8-liter
engine designs. During cruising, the new engine achieves
particularly high fuel economy, on a par with that of a 1.5-liter
engine.
Under low-load conditions on conventional engine, the throttle
valve is normally partly closed to control the intake volume of the
fuel-air mixture. During this time, pumping losses are incurred due
to intake resistance, and this is one factor that leads to reduced
engine efficiency. With the i-VTEC engine, however, intake valve
closure timing is delayed to control the intake volume of the
air-fuel mixture, allowing the throttle valve to remain wide open
even under low-load conditions for a major reduction in pumping
losses of up to 16%. Combined with comprehensive friction-reducing
measures, this results in a significant increase in fuel efficiency
for the engine itself.
A DBW (Drive By Wire) system provides high-precision control over
the throttle valve while the valve timing is being changed over,
ensuring smooth driving performance that leaves the driver unaware
of any torque fluctuations. Other innovations include a
variable-length intake manifold that delivers optimum inertia
effectto further improve intake efficiency and piston oil jets that
cool the pistons to suppress engine knock, for powerful torque even
atrpm ranges typical in normal driving. The new engine delivers a
high level of performance, with maximum output of 103kW (140PS) and
maximum torque of 174N·m (17.7kg·m). It also delivers cleaner
emission performance, employing a 2-bed catalytic converter
positioned immediately after the manifold and high-precision
air-fuel ratio control to achieve emission levels 75% below 2005
Japanese government standards (based on Honda in-house
testing).
In addition, lower block construction resulting in a more rigid
engine frame, aluminum rocker arms, high-strength cracked
connecting rods, a narrow, silent cam chain, and other innovations
make the engine more compact and lightweight. It is both lighter
and shorter overall than the current Civic 1.7l engine, and quieter
as well.
