Engine valves and valvetrain

Eaton's decompression engine braking technology for medium- and heavy-duty diesel engines delivers high braking power and reduces the total cost of ownership (TCO) for truck owners.

Eaton offers rocker arm-based 1 stroke, 1.5 stroke, and 2 stroke systems for overhead cam and cam in block engine architectures.

The compression release engine brake provides several advantages to the commercial vehicle truck owner:

Reduces brake and tire wear
Avoids overheating and fading of primary brakes
Reduces or eliminates the need for a driveline retarder

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Overview Support

Engine Brake types in comparison

1.5 and 2 stroke

Enables one additional brake cycle per cam revolution
Enhances maximum braking power throughout the engine speed range up to 75% vs. conventional single stroke engine brake. Can replace retarder on some applications
Compatible with SOHC and DOHC engine architectures

Hydrogen internal combustion vehicles require robust engine brakes

H2 ICE engines need more engine braking due to their low compression ratio – approximately 11.0:1 compared to a diesel engine’s 18.5:1. To offset the loss in compression power, testing has shown that Eaton’s 1.5 stroke engine brake delivers 40% more braking power at low speed compared to a conventional engine brake. If additional engine braking is required, the combination of an Eaton TVS supercharger and 1.5 stroke engine brake boosts this by an additional 20%.

Learn more about our 1.5 stroke engine brake

Eaton 1.5 stroke engine brake system delivers 50% higher braking power at low speed vs conventional engine braking. This is achieved by having one additional compression release event per engine cycle. A deactivating rocker arm in combination with an engine brake rocker arm disables the regular exhaust valve motion allowing a second valve opening at top dead center.

Dedicated rocker

Single stroke braking
Dedicated brake cam lobe and rocker
Maximum braking power for single stroke systems
Maximum flexibility in cam design
Compatible with SOHC and DOHC engine architectures
Higher space claimed compared to Integrated Rocker solution

Integrated rocker with reset

Single stroke braking
One cam lobe and one rocker for exhaust and brake lift
Re-set during lift: valve closing profile will not change in brake mode
Automatic lash adjustment on brake valve lift
Similar braking performance to Dedicated Rocker
Better packaging than Dedicated Rocker
Compatible with cam in block and SOHC architectures

Integrated rocker without reset

Single stroke braking
One cam lobe and one rocker for exhaust and brake lift
Closing timing delayed in brake mode
Easier packaging than Dedicated Rocker and Integrated Rocker with reset
Compatible with cam in block and SOHC architectures

Core features

Fast response: activation and deactivation within one engine revolution
Minimized load on the system with maximum braking performance: engine brake on one single valve
Tight tolerance control ensures high consistency of valve lift

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Engine Brake