What is "diesel bug" and how can it be prevented?

A. An additive in low-sulphur ULSD that causes filter blockages in warm weather

B. A chemical degradation of diesel that turns it to gel in cold weather — only a problem in winter

C. Rust particles from an old steel tank — only affects vessels over 20 years old

D. Microbial contamination (bacteria, fungi, yeast) that lives at the fuel/water interface in the tank — produces black sludge that blocks filters. Prevention: keep tanks full (reduces condensation), use biocide additive, drain water from primary filter regularly, check tanks annually

A. Compression ignition: diesel fuel is ignited by the heat of highly compressed air (compression ratio ~22:1) — no spark plugs are used. Fuel is injected into the compressed air at the moment of ignition

B. Diesel engines work at lower compression ratios than petrol engines for safety

C. Diesel engines use spark plugs but fire in a different sequence to petrol engines

D. Diesel engines use carburettors to mix fuel and air before compression

A. Compression, ignition, induction, exhaust — the compression happens before air enters

B. Induction (air in): piston down, air drawn into cylinder. Compression: piston up, air compressed to high temperature. Power (ignition): fuel injected, combustion drives piston down. Exhaust: piston up, exhaust gases expelled

C. Ignition, compression, induction, exhaust

D. Induction, power, compression, exhaust