Summary – Fuel Flowmeters in Diesel Engines

Diesel power-units are becoming increasingly popular in a whole variety of power applications. For everything from generators, boats and trains through to hydraulic packs these power sources are becoming the unit of choice. With increasing fuel prices, all sectors of the transport industries, from small trucks to large super-tankers are taking much more interest in their vehicle’s fuel consumption. The possibility of theft, particularly from remote locations makes it unwise to rely solely on a dashboard fuel gauge which simply measures the fuel left in the tank, rather than the use of fuel flowmeters to actually measure the consumption of the engine. Despite some static installations for generators and the like lacking even a dashboard fuel gauge, engine fuel consumption and efficiency is generally not monitored and the unit’s performance is assessed from the manufacturer’s engine test figures and seldom checked again. Whilst vehicle manufacturers do spend a lot of time and effort checking the consumption figures for an engine, this is done on dedicated dynamometers and, later, with very sophisticated mobile set ups. These fuel systems are very costly and are unsuitable for general use, unlike fuel flowmeters. On a typical diesel engine the fuel is supplied to the injectors at pressure from a ‘lift pump’. The injectors use the amount of fuel required for the engine load and return the rest to the fuel tank. If you wish to measure the amount of fuel used you simply need to place one fuel flowmeter in the supply line and a second fuel flowmeter in the return line and use electronics to subtract the difference: simple!