Browse Publications Technical Papers 2008-01-0608
2008-04-14

Development of High-Performance and Low-Emission Gasoline Engine 2008-01-0608

Honda has developed a new 2.4 L engine that clears the U.S. SULEV (Super Ultra Low Emission Vehicle) emissions regulations. The new engine incorporates a unique VTEC mechanism (Variable valve Timing and lift Electronic Control system: It is the mechanism which performs proper use of the valve rocker arms driven by the cams of the different characteristic by the connection or separation of internal organs pistons by oil pressure control.), an integrated exhaust manifold / cylinder head, and a layout featuring a close-coupled catalyst converter to significantly increase power against the previous model, while maintaining that model's emissions performance. A mechanism enabling deactivation of one valve on the exhaust side has been employed in the new VTEC system to reduce emissions and increase low-speed torque. One-valve operation during warm-up from a cold start promotes after-burn of the HC component of the feed gases by increasing the flow motion of the exhaust gas, resulting in a significant reduction of HC emissions. In addition, one-valve operation at low engine speeds when there is a low exhaust gas flow reduces the level of exhaust blow-back into the cylinders caused by exhaust interference, increasing low-speed torque. On the inlet side, a VTEC mechanism has been employed which, in combination with VTC (Variable Timing Control), enables optimum valve timings to be set for the low- and high-speed sides. Decreased intake and exhaust resistance and an increased compression ratio in the new i-VTEC (intelligent-VTEC: it consists of VTEC and VTC) engine, among other factors, have enabled the engine to clear the U.S. SULEV emissions regulations while achieving a power of 190 HP. The new engine will be fitted in some ACCORD models to be marketed in California in 2007.

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