Patent Application
20080078364
Preferred embodiment is shown below as a sample application of this invention. This sample application is suited for a car powered by a direct injection diesel engine. We strive to provide the most complete and full-featured embodiment shown in
High pressure fuel pump 1. Injection control fuel valve 2. Direct injection diesel engine 3.
Heat exchanger 4 to heat compressed fuel by exhaust gases:
fuel pathway made of copper tube wrapped around exhaust path way 5;
or fuel pathway enters exhaust path way coiled inside and exits the exhaust pathway upstream;
or thermo-conductive body having independent, counterflow pathways for fuel and exhaust gases.
Heat exchangers of this kind are common to boilers and chemical reactors.
Heater 6 to heat compressed fuel by combustion heat produced specifically for this fuel heating by burning some of the fuel.
Heater control fuel valve 7 to regulate amount of fuel burned by the heater.
Air pump 8 to feed the heater 6 with air. This could be an electric fan.
Ignition means (not shown) to start combustion of fuel injected via valve 7 into airflow created by pump 8. This could be a spark-plug or a glow plug.
Temperature sensor (not shown) to measure fuel temperature at or before the valve 2. The sensor could be a thermo-couple.
Electronic circuit and/or computer means (not shown) to provide negative feedback control for the valve 7 based upon the temperature of the fuel. This will increase fuel injection into the heater 6 if the temperature is less than desired one and decrease fuel injection if the temperature is above desired value. This type of temperature control is common to boilers and chemical reactors.
Specifics are arising from relatively high fuel temperatures we recommend (300 to 900+degrees Centigrade). The exchanger, the heater and the injection valve are to be designed accordingly. Plastics or aluminum parts will not keep their strengths. Conventional solder contacts in electric circuits will melt; magnetic parts will loose their useful properties and so on.
High temperatures may cause high energy loss. Thermo-isolation is a must. Flammable materials coming in contact may ignite oil and plastic-isolated electrical wiring. Thermo-isolation shall prevent that.
Injection valve may need to be redesigned to avoid use of magnetic materials and other temperature sensitive parts. Alternatively, cooling of the valve's parts may be considered.
First step activates battery powered the fuel pump 1 and the air pump 8. This compresses fuel and prepares for the heater's start.
Second step comes a while after, triggered by a timer or by a fuel pressure sensor. Second step activates the valve 7 and ignites fuel in the heater 6. This warms fuel and catalytic converter 9 preparing for the engine's start.
Third step comes a while after, triggered by a timer or by a fuel temperature sensor. Third step starts the engine.
Following is normal operation of the engine after warm-up. As engine warms, exhaust becomes hot, the exchanger heats fuel as well as heater does further increasing the fuel's temperature. At that point fuel temperature is regulated by the negative feedback control loop using the temperature sensor and the heater control valve 7.
