Ignition improver

In addition to glow plugs or pilot fuel an ignition improver can be used to raise the cetane number of the fuel to promote ignition. Different ignition improvers are commercially available. However, little research has been done on how they work with methanol during the last decade as much attention has been focused on ethanol. Scania have gained extensive experience of using an ignition improver called Beraid in ethanol powered busses.

The similarities between the two alcohols encourage some extrapolation of the results achieved. The Scania engines used for ethanol are diesel engines that have undergone some modifications. In addition to the fuel system that has been adopted for light viscosity fuel the compression ratio of the engines have been raised from 18:1 to 28:1. The fuel used is called Etamax D and consists of, in addition to ethanol, about 5 % ignition improver and 3 % denaturants and corrosion inhibitors. While the ignition improver makes it possible to run the engine according to the diesel cycle and to get quite high efficiency a possible disadvantage is the high cost of the ignition improver. As substantial modifications are still needed to the engine, it is questionable if this is the preferred route for all applications. Still, during the right circumstances it might be a plausible route for particularly smaller engines as an alternative to the use of glow plugs.