Steam at high pressure exhausting into the atmosphere is still commonly used, but the great power required for raising heavy loads from deep pits at high speeds has brought the question of fuel economy into prominence, and more economical types of the two-cylinder tandem compound class with high initial steam pressure, superheating and condensing, have come in to some extent where the amount of work to be done is sufficient to justify their high initial cost.
Honda's 140PS 2.2-litre i-CTDi diesel continues; but as aerodynamic efficiency is improved by 12 per cent, fuel economy should improve.
downdraft kilns in pursuit of fuel economy and improved consistency in temperature achievement.
downsized engines, with significant fuel economy are feasible in the short to medium term.
All others have been found not to increase fuel economy.