What Does DOHC Mean? A Quick Guide
If you’ve ever looked at a car’s specs, you might have seen the term DOHC and wondered what it means. Let’s break it down so you can understand why it matters.
What is DOHC?
DOHC stands for Dual Overhead Camshaft . It refers to an engine design where there are two camshafts located above the cylinder head. One camshaft controls the intake valves, which let air and fuel into the engine, while the other handles the exhaust valves, which push out burned gases. This setup allows for better airflow, more power, and improved efficiency compared to older designs.
How Does It Work?
To understand DOHC, it helps to know how an engine operates. Most modern cars use a four stroke cycle :
- Intake Stroke: Air and fuel enter the cylinder.
- Compression Stroke: The mixture is compressed for a powerful explosion.
- Combustion Stroke: The spark plug ignites the mixture, creating energy.
- Exhaust Stroke: Burned gases exit the cylinder.
The camshafts in a DOHC engine control when the valves open and close during this process. With two camshafts, the engine can operate more valves per cylinder, usually four instead of two. More valves mean smoother airflow, which boosts performance and fuel economy.
DOHC vs SOHC vs OHV
Not all engines are created equal. Here’s how DOHC compares to other designs:
- SOHC (Single Overhead Camshaft): Uses one camshaft for both intake and exhaust valves. It’s simpler and cheaper but less efficient than DOHC.
- OHV (Overhead Valve): Found in older or larger engines, OHV uses pushrods to operate the valves. It’s reliable but struggles at higher RPMs and isn’t as efficient.
DOHC engines are the gold standard in modern vehicles because they offer better performance, efficiency, and adaptability.
Why Should You Care?
If your car has a DOHC engine, it likely delivers more power and better fuel economy than older designs. Automakers like Honda, Toyota, and Ford use DOHC technology to create engines that are both powerful and eco-friendly. For example:
- Honda’s VTEC engines use DOHC to maximize performance.
- Ford’s EcoBoost engines combine DOHC with turbocharging for incredible efficiency and power.
Final Thoughts
DOHC might sound like just another acronym, but it’s a key feature in many of today’s best engines. If you’re shopping for a car and see “DOHC” in the specs, you’ll know it’s a sign of a modern, high-performance engine designed to deliver a great driving experience.