Heavy duty diesel engines featuring exhaust gas recirculation systems are reducing emissions but their higher under hood temperatures are causing havoc to belt drives, shortening belt life and accessory component life. Today’s heavy duty engines are more demanding than ever before and the parts that keep them running require more strength, stability, flexibility, wear ability and load carrying capability.
Gates engineers began working in 2009 on an alternative tensioner to the OE for Detroit Diesel series engines to improve the design and their performance. The new tensioner exceeded the performance of the original part.
This case study provides the background to the new tensioner design and the results of fleet testing.
Detroit Diesel DD13 and DD15 engines were selected for the application and the new tensioner was applied on Freightliner, Cascadia and Coronado among others. Two tensioners were tested in each application.
Gates’ new heavy duty tensioner is designed to replace both the OE tensioners, with its unique design combining the fan and accessory belt drive tensioners on a common bracket. The advanced OE replacement tensioner with heavy duty performance of 550,000km saves both downtime and money. The accessory tensioner arm, due to the lifting feature had to be designed and optimised to ensure it was robust enough for repeated belt installations.
Extensive rig testing and fleet testing was undertaken to validate the new Gates design. Prior to Gates commencing the fleet test, the tensioners went through a 2000-hour durability rig test with heat and dust contamination. The tensioners passed the test, remaining fully functional till the end. Following the rig testing, the tensioner was trialled and tested by having it fitted to a high kilometre fleet.
Upon return from the fleet test the tensioners had exceeded the required 550,000km, accumulating 716,000km with no noise, misalignment or failures reported.
The results of the fleet test indicated that the tensioner assembly was fully functional with plenty of remaining life. The load and damping were within specification and there was minimal wear on pivot bushings, damping mechanisms and shafts. The tensioners were in overall good condition and the results showed excellent signs of durability and reliability.
The new Gates DriveAlign heavy duty tensioner boasts true heavy duty performance of 550,000km plus service life. This advanced OE replacement solution offers any fleet benefits such as reduced downtime and cost per kilometre. The tensioner is more responsive to system load variation, better balanced to provide consistent wear, and easier to install.
Advantages of Gates 38667 tensioners over OE tensioners
OE tensioners use smaller pivot bushings that wear out sooner and make it difficult to maintain alignment. These tensioners also use hydraulic struts, slowing their reaction to the constant changes caused by the fluctuating power requirements of the accessories, which lead to belt flutter and wear.
Key features and benefits of the Gates 38667 tensioners include larger pivot bushing that prolongs tensioner life; longer tensioner arm to reduce pivot bushing wear; balance of loads ensuring proper alignment of the tensioner; double row pulley bearings proven to last longer; higher damping reducing arm movement; designed for the heavy duty market; and easier to install.
Gates recommends the use of the highly durable DriveAlign tensioner with Gates FleetRunner belts to derive multiple advantages including prolonged replacement intervals, reduced maintenance costs and low cost per kilometre.