Development of CNG Engine with Variable Valve Timing Electronic Control

Honda has developed the Compressed Natural Gas (CNG) engine with Variable Valve Timing Electronic Control. This new engine was designed to further enhance power and efficiency: increased engine displacement and the use of a variable-length air intake manifold have achieved a 15% enhancement in power. In addition, engine fuel consumption has been reduced by 5% through a combination of reduced pumping loss due to inlet valve control for delayed closure, and charging stroke injection timing that harnesses the properties of gaseous fuel. As a countermeasure for tail pipe emissions, an exhaust manifold integrated with the cylinder head and a close coupled two bed catalyst have been used. As a result, the use of precious metals has been reduced by approximately 30%, and the vehicle with the new engine complies with CARB's AT-PZEV standard.