What does DOHC engine mean?
3 Answers
DOHC (Double Overhead Camshaft) has two overhead camshafts placed on the cylinder block. The first one drives the intake valves, and the second one drives the exhaust valves. Here is a related introduction to DOHC: 1. Function: The camshaft belongs to the valve train of the engine. The valve train ensures that the engine regularly fills the cylinder with fresh combustible mixture during operation and promptly exhausts the burned gases from the cylinder. 2. Composition: It consists of intake valves, exhaust valves, valve pushrods, lifters, rocker arms, camshafts, etc. Among them, the camshaft, whose cross-sectional shape resembles a peach, is also called a peach shaft or eccentric shaft. It is the driving component in the valve train, specifically responsible for opening and closing the valves on time. 3. Position: The structure of camshafts in various vehicle engines is largely similar, with the main differences lying in the installation position, the number of cams, and their shapes and sizes. Particularly, the installation position of the camshaft is considered an important indicator for distinguishing engine construction and performance. Currently, the camshaft installation positions in engines are divided into three types: lower, middle, and overhead.
When I first got into cars, my mentor explained DOHC engines to me. The full name is Double Overhead Camshaft, meaning there are two camshafts at the top of the engine that separately control the intake and exhaust valves, allowing for more precise valve timing. From my personal experience, cars with this type of engine have quicker throttle response during acceleration and smoother power delivery, without the occasional stutter you get with older single camshaft designs. This configuration also reduces engine vibration and offers better fuel efficiency for daily driving. Plus, it maintains stability at high RPMs, making it ideal for highway conditions. Maintenance isn't too complicated – just regular checks of the timing chain and lubrication. Overall, DOHC improves fuel efficiency and is a common technology in modern engines.
I often drive different car models, and the DOHC engine gives me a feeling of direct and powerful power output. It is actually a dual overhead camshaft design, with each camshaft controlling a set of valves, optimizing airflow and the combustion process. This gives me more confidence when overtaking at high speeds, and the engine noise is also lower. Compared to SOHC (single overhead camshaft), it is much more responsive, especially during stop-and-go traffic at traffic lights or when climbing hills, making it effortless. Daily fuel consumption is also relatively low, and after long-term use, I have rarely encountered major issues. Some mid-to-high-end brands like Toyota commonly use it due to its high reliability. Regular oil changes can ensure a long lifespan and stable performance.
