What type of engine does the original Beetle use?

The original Volkswagen Beetle used an air-cooled flat-four engine.

Its horizontally opposed four-cylinder engine was mounted at the rear and drove the rear wheels. The layout helped preserve cabin space, gave the car good traction on slippery surfaces, and avoided the need for a radiator, coolant, and front-mounted engine plumbing.

Air cooling was especially practical for a simple, economical car. Cooling air was directed over the cylinders and cylinder heads by a fan and shrouding. The engine design evolved over the decades, with displacement increasing from early versions of about 985 cc to 1.6 litres in later standard Beetles.

A flat-four is also called a boxer-four because opposing pistons move outward and inward in pairs. The answer is not “inline-four”: that configuration places all cylinders in one row. The Beetle’s engine was petrol-powered, not rotary or V6, and its rear placement was one of the model’s defining engineering features.