Honda City ZX Technology

Honda's intelligent Dual and Sequential Ignition (i-DSI) engine is the second i-Series engine, next to i-VTEC, that employs compact combustion chambers and two spark plugs per cylinder with individually controlled ignition timing for more rapid and complete combustion.

In developing the i-DSI engine, the objective was to achieve rapid and complete combustion. Since the Honda CVCC days in the early 1970s, Honda has been a great believer in optimizing the combustion process as a means of achieving high performance, high fuel economy and low toxic emissions. In the i-DSI engine, they would seem to have been able to achieve all three.

Narrower valve angles and other refinements have been employed to make the combustion chambers as compact as possible. The i-DSI engine employs an innovative twin spark plug system (two spark plugs per cylinder) for maximum combustion efficiency. In addition, the combustion chamber has been engineered to promote greater swirl of the air-fuel mixture.

The intake manifold shape has also been shaped and its length optimized.

Other refinements include world-leading friction reduction technology utilizing molybdenum-impregnated piston skirts, a rear-port exhaust system and an oblique-feed catalytic converter. And though the 1497 cc long-stroke engine has two valves per cylinder and only a single overhead camshaft, its output is a respectable 77Bhp at 5000 rpm with 125 Nm of torque peaking at a low 2700 rpm.