more efficient

less efficient

equally efficient

unperdictable

more

less

same

more/less depending on capacity of engine

1 sec

0.1 sec

0.01 sec

0.001 sec

piston ring and cylinder wear

formation of hard coating on piston skirts

oil sludge in the engine crank case

detonation

using additives in the fuel

engine derating i.e. reducing the maxi-mum flow of fuel

increasing the compression ratio

adherence to proper fuel specification