The Protection System for Diesel Injection Modern diesel engines use a higher injection pressure due to advanced performance requirements. Not only dirt particles but also water droplets have a direct effect on components of the injection system. This is particularly important for modern common rail systems, which place high demands on fuel quality. The injection systems used have very high requirements regarding cleanliness of the fuel. This means the fuel should contain hardly any particles and practically no water (condensate). Fuel pre-filters from MANN+HUMMEL reduce the level of contamination of the fuel with water even before the feed pump in the low-pressure circuit, thus reliably protecting the injection system. MANN+HUMMEL uses high performance multigrade media for the filtration of the fuel. The PreLine system protects the feed pump against ingress of water and coarse particles and extends the service life of the main filter. The PreLine series separates more than 93 % according to ISO/TR 16 332 of water present in the fuel and so fulfils the requirements of leading injection system producers.