Provisional Patent Filed 2/18/2010 - Application # 61/305,813

Low cost temperature activated fuel controller utilizing a snap action
bimetal thermostat allowing diesel engines to utilize waste vegetable
oil (wvo) as a fuel

This patent is for a simple, low cost fuel controller used to allow diesel engines to
utilize waste vegetable oil as a fuel. The controller uses a snap action bimetal
thermostat (in a normally open configuration) to close a circuit at a factory pre-set
temperature, which activates a relay and energizes an electronic 3-way solenoid
valve to switch between diesel fuel to wvo fuel (wvo/diesel mixture – hereafter
wvo will refer to either 100% wvo or a blend of wvo and diesel). The 3-way
solenoid valve’s default (non-energized) state routes diesel from the regular tank
to the engine’s injector pump. When energized, the 3-way solenoid valve
switches to the other position, which then changes the routing of the fuel to come
from the alternate wvo tank. The purpose of this controller is to achieve ideal wvo
fuel temperature prior to switching to the wvo tank. Any diesel can use wvo as a
fuel, except the fuel needs to be heated in order to lower the viscosity so that the
diesel engine can achieve complete, efficient combustion. Many existing
controllers utilize a PLC or some means of electronic controls to perform this
switching function. This controller is different in that it solely relies on the use of a
snap action bimetal thermostat to control the switching to the wvo once the
predetermined (and preset) temperature is reached. This significantly reduces
the cost of these controllers. This controller also includes the use of optional,
high temperature controls also based on the same snap action bimetal
thermostats (except these will be in a normally closed configuration) to prevent
overheating of the wvo in certain circumstances. This patent also covers the use
of a snap action bimetal thermostat to control the flow of wvo fuel delivered to an
engine in any way.