# Subaru's Hollow Camshaft Patent Reduces Engine Vibration

> Subaru patent for vibration-reducing hollow camshaft with lockable balance weight.
- Title: Subaru's Hollow Camshaft Patent Reduces Engine Vibration
- Summary: Subaru patent for vibration-reducing hollow camshaft with lockable balance weight. Subaru's new patent describes a hollow camshaft with a lockable balance…
- Keywords: subaru, hollow camshaft, patent, balance weight, engine vibration, camshaft design, uspto, cars, Subaru's, Hollow, Camshaft, Reduces
- Source: Car and Driver — https://caranddriver.com/news/a74158213/subaru-patent-details
- Author: Sebastian Blanco
- Published: 2026-10-16T14:51:27+00:00
- Read time: 1 min
- Topics: subaru, hollow camshaft, patent, balance weight, engine vibration, camshaft design, uspto, cars
## 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.
## Key takeaway

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.