Low- And High-Compression Fuel Economy Engines: The Techniques Are About The Same, But The Approach To Each Is Somewhat Different. A. Most stock cylinder heads have factory-cut undercuts of the ...

Is that knocking sound your engine is making just a case of low-octane fuel, or is it something more serious? The answer is crucial for your engine's health.

Not enough compression usually means misfires, rough idle, and hard starts on a traditional diesel engine. Mazda overcomes these issues with the SkyActiv-D by incorporating many different ...

SAE International Journal of Engines, Vol. 2, No. 1 (2009), pp. 1574-1586 (13 pages) ABSTRACT The objective of this study was to examine the operating characteristics of a light duty multi cylinder ...

What is a Nissan VC-Turbo? The innovative engine architecture, launched on the company's premium 2019 Infiniti QX50, promised to solve a recurrent problem with low-compression turbocharged engines ...

But too high a ratio causes knocking—premature detonation of fuel-air mixture during the engine's compression stroke caused by high cylinder temperatures.

A significant issue of a high compression ratio engine for improving fuel economy and low-end torque is prevention of knocking under a low engine speed. Knocking is caused by autoignition of the ...

The Flathead was also a very low compression engine, with Fenske noting the earliest 65-hp 3.6-liter variant had a compression ratio of just 5:1.

Nissan’s variable-compression engines have been flagged in a new lawsuit. In June 2025, Nissan issued a recall for approximately 480,000 vehicles equipped with defective VC-Turbo engines. Now, a class ...