Dual Fuel Engine
DF or Duel Fuel Engines are the kind of engines which could work on a mixture of diesel fuel and gas fuel or it can work on diesel fuel alone. Duel Fuel engines could not work on gas alone since they do not posses an ignition system, nor do they possess any spark plugs.

Because the engine is not a pure diesel engine and diesel is not a pure gas, this machine does suffer from poor fuel efficiency and Methane slippage. For example, the fuel efficiency may be 5% to 8% less than in a comparable spark-ignited, lean burn engine at 100% load. It could even be lower or higher loads.

Lift Truck Classification and Fuel Sources
There are certain recycling materials handling applications which can prove extremely difficult for lift trucks. For example, scrap metal is amongst these problems. To be able to successfully handle things like this needs utilizing the correct type of machine for the task.

There are 7 major lift truck classes, including power sources like hydrogen fuel cell, liquid propane gas, diesel, electric and gasoline. The power source is linked to some of these specific classes. The main power sources for forklifts include Diesel, Gasoline, Battery, Propane and Fuel Cell.

The most common overall are electric powered trucks, mainly in Class I, II and class III forklifts. In Classes V and IV, internal combustion trucks are more popular. The most popular electric power source is the lead-acid battery. Amongst internal combustion trucks, roughly over 90% are powered by propane.

The most popular power source for lift trucks is battery. Battery powered units make up roughly 60% of the new forklifts sold within the USA. Their benefits include: less maintenance requirements, quiet operation, the ability to be used outside and indoors with no harmful emissions.