What is a Hemi Engine
If you’ve ever wondered, “What is a hemi engine?” you are not alone. Car lovers speak of the hemi as if it were the best thing you could have under your hood. The term Hemi comes from the word hemisphere and is used to describe an internal combustion engine in which the cylinders in the combustion chamber are topped with a hemispherical roof.
If you are asking what is a hemi engine and what makes it so special, the answer gets a little bit technical. When the combustion chamber is hemispherical, the valves for intake and exhaust are on opposite sides as compared to a traditional engine in which they are on the same side. When the valves are side-by-side, the flow of the air and fuel mixture through the chamber can be restricted. In a hemi, the flow path is straight.
The design of a hemi engine allows it to get create more power than an engine with a flat or wedge-shaped combustion chamber. What is a hemi engine’s drawback? Hemi engines are heavier and more expensive to produce and they struggle to meet modern emission standards.
In spite of the negatives, the powerful hemis were popular in their early history. First introduced in a Jaguar in 1948, it was Chrysler that made the hemi so famous. They even trademarked the term “Hemi.” The first Chrysler Hemi, introduced in 1951, was rated at 180 horsepower, which in its day was an unheard of power rating. Throughout the ‘50s and ‘60s, the Hemi continued to be popular in both consumer models and race cars.
So, what is a hemi engine in today’s market? Chrysler reintroduced the Hemi in 2003 Dodge trucks. Although they are no longer truly hemispherical in the combustion chamber, they are still big and synonymous with power.