Abstract: An improved circulating fuel heating system for internal combustion engines of both gas and diesel types. The system is sizeable through staged heat exchanger components to provide the necessary fuel heating for various engine sizes and fuel consumption rates in order to maintain the temperature of the fuel entering the carburetor bowl to just above the temperature of vaporization for the fuel.

Abstract: A circulating fuel heating system for internal combustion engines of both gas and diesel types. The system is sizeable through staged heat exchanger components to provide the necessary fuel heating for various engine sizes and fuel consumption rates. The system basically comprises a plurality of staged fuel/hot water heat exchangers, a fuel controller interposed between the heat exchangers and the carburetor bowl, a by-pass/metering valve and a vapor capture system for returning unused fuel to the heat exchanger and a fuel/exhaust manifold heat exchanger operably connected to the controller to satisfy initial heating requirements for the period after cold-engine starting.