Technical Committee Automotive Fuels

Requirement of today‘s diesel passenger vehicles regarding low temperature stability of the fuel

The determination of the cold operability limit of diesel fuels is currently carried out in the Ford Escort 1 .6D, based on testing method CEC M-11 -T-91. The test vehicle used here 15 a vehicle model from the 80‘s, which is represented in this design only in a small number of items (< 1% market share within the diesel passenger car pool) in the German market.
The purpose of this investigation was to determine the requirement of today‘s vehicies regarding low temperature stability of the fuel and should the situation arise replace the Ford Escort 1 .6D by an actual vehicle. Therefore passenger cars equipped with different diesel engines were selected, representative for the current vehicle population, and the cold operability behaviour was determined by two reference fuels.
The results show that the operability limit mainly depends on the fuel filter systems with respectively without a fuel preliminary heating. Vehicles without any preliminary heating system have a high requirement to the low temperature stability of diesel fuels. Vehicles with a complex diesel filter preliminary heating system achieve the operability limit of -22 °C even with the critical reference fuel with regard to a low temperature stability.
A direct dependence on the laboratory testing method CFPP and the operability in the vehicle tests could not be identified.
Vehicles of the series VW Golf 1,9 TDI or VW Passat 1,9 TDI PD seam to be suitable to determine the operability. Both have a rebatively high requirement to the low temperature stability of diesel fuels and a relatively high market share.
This investigation even shows, that only the balance of vehicle concepts and fuel quality assure sufficient and acceptable operability for the customer by low temperatures.