Which is better, Honda sohc or dohc?

SOHC: single overhead camshaft, which means single overhead camshaft engine, that is, an intake valve and an exhaust valve. At low speed, the torque is greater and the explosive force is better than that of the same displacement DOHC engine.

Dohc: twin-cam, which means dual camshaft engine, generally has multiple valves per cylinder, generally four valves (i.e. two intake valves and two exhaust valves). The multi-valve engine burns more fully, allows more fresh air to enter the engine, and has better emission efficiency (the structure is more complicated than SOHC). Generally speaking, DOHC does have strong high-speed power, but the fuel economy and low-speed torque are far from those of SOHC engines with the same displacement.

What is the function of the engine ignition system?

The automobile ignition system is a spark ignition engine. According to the ignition sequence of each cylinder, high-voltage electricity (about 15000 ~ 30000V) with high enough energy is regularly supplied to the spark plug, so that the spark plug can generate strong enough sparks to ignite the combustible mixture. When the engine is working normally, only 1~5mJ spark energy is needed because the temperature at the end of mixture compression is close to its auto-ignition temperature. However, when the mixture is too rich or too lean, when the engine starts, idles or the throttle valve suddenly opens, higher spark energy is needed.