Another fuel that utilizes a variation of the internal combustion engine, diesel fuel finds much of its use in industrial engines where more torque is necessary. Diesel doesn’t ignite in the same way that gasoline does. Instead of using a live spark to initiate combustion like a gasoline engine, diesel engines compress the air before injecting the fuel, which then ignites. This difference in ignition systems allows diesel to produce more power from each cylinder. Diesel is also a more efficient fuel, however that increased range comes with some trade-offs. Because diesel is a denser and more oily fuel, the emissions from it tend to be harsher and contain more soot than gas. While the amount of CO is comparable to petrol engines, the compression process in diesel engines creates more nitrogen oxides which are toxic. Historically, diesel has been cheaper to buy than gas, but that has changed over the last few years as the US and China have ramped up construction and more diesel daily drivers have hit the market place.