Auto Service World
News   July 5, 2005   by Auto Service World

Honda Develops New Engine With Enhanced Fuel Economy and Improved Performance


Honda Canada Inc. announced today it will introduce a new 1.8-litre i-VTEC engine this fall in the new 2006 Honda Civic coupe and sedan models designed to achieve both more powerful performance and enhanced fuel economy. The new engine uses an “intelligent” i-VTEC system that switches the valve timing for maximum efficiency during startup and acceleration to achieve powerful performance with excellent torque output, then delays intake valve closure timing during cruising and other low-load conditions for enhanced fuel economy. Use of the valve timing control system results in off-the-line acceleration performance at low rpm equivalent to that of a 2.0-litre engine with fuel economy that is up to six per cent(1) better than the current 1.7-litre Civic engine, making it one of the world’s most efficient 1.8-litre engine designs. During cruising, the new engine achieves particularly high fuel economy, on a par with that of a 1.5-litre engine. With the new i-VTEC engine, 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 per cent. Under low-load conditions on a conventional engine by comparison, the
throttle valve is normally partly closed to control the intake volume of the air-fuel mixture. During this time, pumping losses are incurred due to increased intake resistance, a significant factor that leads to reduced engine efficiency. The new i-VTEC engine minimizes this pumping loss effect to increase efficiency. Combined with comprehensive friction-reducing measures, the delayed
intake valve closing results in a significant increase in fuel efficiency for the engine itself. A drive-by-wire (DBW) throttle control system provides a highly precise 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 effect to further improve intake efficiency for powerful torque delivery at rpm ranges typical in normal driving. Piston oil jets
reduce piston operating temperatures, which help suppress the possibility for engine knock in an engine with a 10.5:1 compression ratio.Overall, the new engine delivers a high level of performance with maximum output of 140 horsepower and maximum torque of 128 lb.-ft. It also
delivers enhanced emissions performance by employing a 2-bed catalytic converter positioned immediately after the manifold and a high-precision air-fuel ratio control to achieve Tier 2 Bin 5 emission levels.The more powerful engine is both lighter and shorter than the current
Civic 1.7-litre engine, and quieter as well. The engine’s lower block construction results in a highly rigid design. Innovations that help make the engine more compact and lightweight include aluminum rocker arms,high-strength cracked connecting rods, and a narrow, silent cam chain.
The Honda Civic has been the top-selling passenger car in Canada for the past eight years.


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