The Centaflex-TIR dual-stage torsional roller coupling is said to help these downsized engines achieve the lowest idling speeds, allowing end users and OEMs to reduce fuel consumption and carbon dioxide (CO2) emissions in operation.
Stage V is an EU emissions standard applying to non-road mobile machinery with spark or compression ignition engines. Diesel engines built to this specification are claimed to be more efficient, power dense and produce less CO2 and nitrogen oxide emissions. This is possible thanks to downsizing and delivering peak torques at lower rotations per minute (rpm).
However, smaller, power dense engines operating at reduced rpm are said to create increased torsional vibrations, especially at idle, which must be dampened to ensure the reliability of powertrain ancillaries such as gearboxes, pumps and generators. Most flexible couplings are too dynamically rigid for Stage V applications, forcing the engine to run at higher idle speeds to prevent overload, protect equipment and safeguard uptime. While increasing rpm reduces vibration, it negates the inherent efficiency benefits of Stage V designs.
The Centaflex-TIR dual-stage torsional roller coupling can accommodate high torques from electric drives. Consequently, this solution offers reliable torque transmission for the next generation of agricultural, construction, mobile crane, marine, quarry and genset equipment.
Two rows of flexible rubber rollers deliver the coupling’s dampening characteristics. Developed from the proven Centraflex-R, the TIR is claimed to be twice as flexible and offers an 80% improvement in thermal load capacity at higher alternating torques compared to its predecessor. A corresponding 80% increase in permissible power loss ensures that it effectively absorbs vibration, preventing coupling overload and alternating torque spikes in the powertrain.
The potential emissions reductions and fuel savings that can be achieved using the Centaflex-TIR were demonstrated during a recent project with a mobile crane OEM. A crane spent 60% of its operating time at idle, and the lower engine rpms supported by the coupling unlocked a fuel saving of 0.9 litres per hour and an annual CO2 reduction of 1.86 tonnes. Furthermore, the fuel cost saving offered an accelerated return on investment.
According to Centa Couplings, OEMs using Centaflex-TIR need not over specify power transmission components to withstand increased vibration. Instead, OEMs can downsize ancillaries, optimising packaging and reducing equipment footprint. As well as a design benefit, this decreases procurement costs too.
The Centaflex-TIR is now available in standard sizes with torque capacities ranging from 2.4 to 10 kNm, with support up to 15 kNm planned. This makes it suitable for the off-highway and genset markets, as well as small to medium marine applications. Custom flange connections and hubs are also available to meet varying OEM interfaces. With the advent of Stage V and the Stage VI design process underway, the Centaflex-TIR is a coupling ready for the current and future transmission requirements of modern diesel engines and electric drives.