January 23, 2017 – As automakers strive to improve fuel economy, reduce emissions worldwide and decrease noise, vibration and harshness (NVH), Dayco has developed a new crankshaft decoupler solution that helps to address these needs.
Dayco’s Damper and Decoupler with Compression Spring (DDCS) system, the company’s newest accessory belt drive product, offers benefits that align directly with the industry’s move toward small, high-power density engines and the increased use of belt starter generator (BSG) systems.
Modern high-efficiency and downsized engines, such as turbocharged 4-cylinder engines, can reduce carbon dioxide (CO2) emissions and fuel consumption through the reduction of friction and improvements in combustion efficiency.
Decoupler for Conventional Accessory Belt Drive Systems
Higher vibrations generated by newer engines are related to the increase of peak cylinder pressure, optimization of the crankshaft for weight, cylinder deactivation, and general reduction in the number of cylinders. The presence of one or more of the aforementioned factors causes increased torsional vibrations of the crank-train which are then transferred through the crankshaft damper pulley into the accessory belt and the accessory drive consequently suffers.
The Dayco DDCS is the solution developed to increase efficiency and reliability while reducing noise generated by modern accessory belt drives. The function of the DDCS is to isolate the belt drive from the vibrations produced by the crankshaft, minimizing the mentioned negative effects.
The DDCS accurately isolates the vibrations coming from the engine as the crankshaft is connected to the belt with coil arc springs designed to transmit power to engine accessories in the smoothest manner possible. The measured isolation rate of the DDCS is up to 90 percent, which means that only 10 percent of the vibrations produced by the engine are transmitted to the belt even when the engine is operating at full power.
The robustness and endurance of the product is validated through severe engine and vehicle test plans in all operating conditions to guarantee proper function for the complete vehicle life.
By utilizing Dayco’s DDCS, tests have shown a reduction of energy losses in the accessory belt drive system caused by tension, belt micro-slippage/flapping and belt width. Power losses can be reduced by as much as 30 percent with the Dayco DDCS. Product durability, meanwhile, can be increased given that the width of the accessory drive belt can also be reduced, further increasing efficiency. Designing the engine with a BSG system allows up to 15 percent CO2 reduction.
The Dayco DDCS also addresses industry trends by reducing NVH and increasing the life of belt drive components because of reduced dynamic loads.
“Dayco provides a vital solution as automakers continue to downsize engines and increase the proliferation of belt starter generator systems,” said Paul DiLisio, Senior Vice President of Automotive and Industrial OE Sales at Dayco. “Our products are applicable in both combustion engine and hybrid electric vehicles in accessory drive and primary drive systems. Our technological innovation also enables the trend toward powertrain electrification.”
The Dayco DDCS is one of the latest solutions created by the 111-year-old company known for its innovative designs of engine products and drive systems.
Dayco is a global leader in the research, design, manufacturing and distribution of essential engine products, drive systems and services for automobiles, trucks, construction, agriculture and industry.
Dayco’s contributions are integral to how people get from place to place, goods are transported, food is harvested, and infrastructure is built. The company operates according to long-held values — keeping promises, delivering on time all the time, and an intense commitment to service no matter what the obstacles. For more than a century, Dayco has overcome challenges, emerging stronger and smarter at every turn.
Dayco improves how the world moves by creating products, systems and relationships that endure.
Move Forward. Always. ™