Systems and methods for pilot fuel synthesis using engine waste heat

A method of operating an internal combustion engine, comprising:

• directing a primary fuel from a primary fuel tank into a first heater of a pilot fuel system;
• exchanging heat between the primary fuel in the first heater and a first fluid from the engine to increase a temperature of the primary fuel from an initial temperature to a first temperature;
• directing the primary fuel at the first temperature into a second heater;
• exchanging heat between the primary fuel in the second heater and a second fluid from the engine to increase the temperature of the primary fuel in the second heater from the first temperature to a second temperature;
• directing the primary fuel from the second heater into a reactor of the pilot fuel system;
• converting the primary fuel in the reactor into a pilot fuel through a dehydration reaction in the reactor;
• storing a portion of the pilot fuel in an accumulator;
• and
• maintaining a level of the portion of the pilot fuel stored in the accumulator within an operational range.

A pilot fuel system configured to generate a pilot fuel from a primary fuel, the pilot fuel system comprising:

• a pilot fuel pump fluidically connected to the primary fuel tank, the pilot fuel pump configured to pump the primary fuel from the primary fuel tank;
• a first heater fluidically connected to the pilot fuel pump to receive the primary fuel from the pilot fuel pump, the first heater configured to exchange heat between the primary fuel and a first fluid from an engine to raise a temperature of the primary fuel from an initial temperature to a first temperature;
• a second heater fluidically connected to the first heater to receive the primary fuel from the first heater, the second heater configured to exchange heat between the primary fuel and a second fluid from the engine to raise the temperature of the primary fuel from the first temperature to a second temperature;
• a reactor fluidically connected to the second heater to receive the primary fuel from the second heater, the reactor configured to convert the primary fuel received from the second heater from an alcohol to an ether, wherein a product of the reactor comprises the pilot fuel, unreacted primary fuel, and water;
• a condenser that receives the product of the reactor, the condenser configured to condense the unreacted primary fuel and the water in the product received from the reactor into liquified unreacted primary fuel and water;
• a separator that receives the liquified unreacted primary fuel and water and pilot fuel, the separator configured to separate the pilot fuel from the liquified unreacted primary fuel and water;
• a waste pump that receives the liquified unreacted primary fuel and water from the separator, the waste pump configured to pump the liquified unreacted primary fuel and water to the primary fuel rail;
• a product pump that receives the pilot fuel from the separator, the product pump configured to pump the pilot fuel converted from the primary fuel to an accumulator for use by an internal combustion engine;
• and
• a controller to maintain a level of the pilot fuel stored in the accumulator within an operational range, the controller configured to change a speed of the pilot fuel pump to change a rate of production of the pilot fuel.