From Car and Driver · Sebastian Blanco · · 1m 10s
Subaru's Hollow Camshaft Patent Reduces Engine Vibration
Subaru patent for vibration-reducing hollow camshaft with lockable balance weight.
In brief
Subaru patent for vibration-reducing hollow camshaft with lockable balance weight. Subaru's new patent describes a hollow camshaft with a lockable balance weight that reduces engine vibration by adjusting its position based on engine speed. Originally reported by Car and Driver.
Subaru Files Hollow Camshaft Patent
Subaru has filed a patent application for a hollow camshaft that could help its engines operate more smoothly and with less vibration.
Hollow Camshaft Design Details
The patent adds a balance weight to the shaft to curb vibration caused by exterior cams, locking it at lower speeds and releasing it at higher speeds.
Patent Application Number
The patent (application number 19/638,324) was filed in April 2.026 and published earlier this month.
Lock Mechanism Function
Lock pins shift from locked to unlocked positions by centrifugal force when the camshaft speed crosses a predefined threshold.
Engine Compatibility
The patent describes use in a four-cylinder horizontally opposed engine but could also apply to V or inline engine designs.
Historical Context
The concept dates back to Mesopotamia, where it was found in Ismail al-Jazari's writings from 1206, now 800 years later.
The headline
Subaru's new patent describes a hollow camshaft with a lockable balance weight that reduces engine vibration by adjusting its position based on engine speed.
