Then there is biodiesel which is mainly made of agricultural materials. For instance, there are two types of standard diesel fuel: Diesel #1 (or 1-D) and Diesel #2 (or 2-D). Technically, there are three types of diesel fuel options, but it is essential to break down the details. So what makes diesel so special, and how can we better understand diesel fuel in order to use the right ‘type’ for our specific diesel engine? Let’s find out. Having knowledge on important topics that affect one’s life, is always a good thing. Understanding diesel fuel types is essential when driving any diesel engine system.