FUEL TYPE ESTIMATION SYSTEM, DATA ANALYSIS APPARATUS, AND CONTROL APPARATUS FOR FUEL SUPPLY APPARATUS

A fuel type estimation system configured to estimate a type variable related to a type of fuel in an engine system including an engine and a fuel supply apparatus includes a storage device and an execution device. The storage device is configured to store a mapping that uses, as inputs, input variables including an engine variable related to a condition of the engine and outputs the type variable. The execution device is configured to acquire the input variables, and estimate the type variable by applying the acquired input variables to the mapping.