BARSINGHAUSEN, Germany – Federal-Mogul Powertrain said it will launch a new, smaller version of its Rotocap valve rotator at IAA Cars 2017 in Frankfurt.
The valve rotator is the first for four-valve-per-cylinder light-vehicle engines, according to the company.
With an outer diameter between 20 and 25 millimeters, the miniaturized design allows the Rotocap to package into the valve assembly on automotive powertrains.
“Rotocap provides the enhanced valve-rotation control required to compensate the challenges caused by reduced valvetrain lubrication and engine down-speeding – two main design trends to achieve lower emissions and improve fuel efficiency,” Federal-Mogul said.
The new mini Rotocap will be marketed alongside Federal-Mogul Powertrain’s existing valve-rotator products.
“The design function of a Rotocap has been proven in the heavy-duty sector, where often engines run too slowly to generate consistent valve rotation,” explained Gian Maria Olivetti, chief technology officer for Federal-Mogul Powertrain. “Today´s non-clamping cotters used in light vehicles allow free rotation of the valve, transmitting spring loads via beads and grooves. However, this free valve rotation is limited in a speed range below 2500 rpm due to low dynamic effects. We can now apply the Rotocap technology to light vehicles, where down-speeding trends and increasing urban traffic density require engines to operate for prolonged periods at low speeds, and therefore may require forced valve rotation. Hybrid applications operating in a limited rpm range will also benefit from this technology.”
Why Valve Rotation Matters
Valve rotation ensures an even distribution of temperature around the seat, increasing durability by reducing local distortion and avoiding blow-by and crack formation across the sealing surface. In addition, rotation reduces wear on other components in direct contact with the valve.
Rotocap eliminates uncontrolled rotation that normally – by torsion of the valve spring or by miscellaneous resonances – is transferred to the valve during its opening and closing movement, according to Federal-Mogul Powertrain. It is replaced with motion through a defined angular movement that only takes place as the valve opens. This controlled movement can be relied upon across the whole engine-speed range, according to the company.
Rotocaps also reduce abrasive wear of the valve-seat area because the valve no longer rotates as it closes.
“This is particularly beneficial on engines designed with reduced oil consumption on the valvetrain or engines using alternative fuels (e.g. LPG, CNG, ethanol) with generally higher seat-wear ratios than gasoline or diesel,” the company added.
At IAA Cars 2017, Federal-Mogul Powertrain will exhibit a range of core valvetrain products such as valves, cotters and valve rotators, including its alternative-design Rotocoil, which uses a single garter spring in place of the balls and ramps. The company will be at Booth E33 in Hall 4.1 from Sept. 12-15.
