Truck Field Test vs. Bench Engine - A Comparison

Volvo Trucks has relied on field testing for the evaluation of lubricants for application in their engines. The initial Volvo VDS specification was upgraded first to VDS-2 and later to the current VDS-3 specification. In VDS-3 an engine lubricant is evaluated in a number of Volvo trucks over 3 drain periods of 100,000 km each. However, covering 300,000 km takes a considerable amount of time and the process of engine inspections and rating the various parts consumes a significant amount of resources. Engine oil performance screening would therefore be preferably done in an engine bench test of shorter duration and of better controlled operating conditions. Volvo Technology, I.S.P. Institute for Fuels and Lubes Testing and Chevron Oronite are very interested in correlating engine bench results with the outcome of VDS-3 field trials. In this paper, we evaluate a lubricant for 400 hours in a Volvo D12D engine run at I.S.P. Intermediate inspections were done at 200 and 300 hours. The results are compared with the outcome of VDS-3 field tests on the same lubricant. In addition intermediate piston inspections in a Volvo VDS-3 test will be discussed. It is concluded that 400 hours in a Volvo D12D engine corresponds to approximately 200,000 km in a Volvo VDS-3 field test.