Method and apparatus for liquefying and/or heating a fluid

Claim 2

In a fuel system for diesel internal combustion engine of a vehicle having a storage battery and an alternator supplying current to said battery, said system comprising fuel injection nozzles, pump means for supplying liquid fuel under pressure to said injection nozzles, fuel filter means immediately upstream of said pump means for filtering fuel supplied to said pump means, a fuel tank and a fuel line connecting said fuel tank with said filter means, the improvement comprising an electric heating element for heating fuel in said fuel line immediately upstream of said filter means to a temperature below the vaporization point to avoid filter-clogging deposits in said filter means, means for sensing the the temperature of fuel in said fuel tank, and an electric circuit supplying current from said alternator and battery to said heating element, said circuit including first switch means controlled by said temperature sensing means and second switch means connected in series with said first switch means and controlled by contact means controlling operation of the engine means to supply electricity to the electric heating element to heat the fuel only when said engine is in operation and when the temperature of fuel in said fuel tank is below a predetermined value.

Claim 3

A fuel system according to claim 1, in which said temperature sensing means comprises a probe in said fuel tank for sensing the temperature of fuel in said tank.

Claim 4

A fuel system according to claim 1, in which said temperature sensing means comprises a probe in the vicinity of said fuel tank for sensing ambient temperature to which said fuel tank is subjected.

Claim 5

A fuel system according to claim 1, in which second temperature sensing means senses the temperature of the fuel between said heating means and said filter and controls said heating means to turn off said heating means when the temperature of the fuel downstream of said heating means exceeds a predetermined value.

Claim 6

A fuel system according to claim 1, in which third switch means connected in parallel with said second switch means is controlled by said alternator to be closed only when said alternator is producing a voltage.

Claim 7

A fuel system according to claim 1, in which said temperature sensing means has a maximum threshold of between 45° C. and 50° C.

Claim 8

A fuel system according to claim 1, in which a return line is connected between said fuel line downstream of said heating means and said fuel tank to return a portion of heated fuel to said fuel tank.

Claim 9

In a fuel system for a diesel internal combustion engine of a vehicle having a storage battery and an alternator supplying current to said battery, said system comprising fuel injection nozzles, pump means for supplying liquid fuel under pressure to said injection nozzles, fuel filter means upstream of said pump means for filtering fuel supplied to said pump means, a fuel tank and a fuel line connecting said fuel tank with said filter means, the improvement comprising an electric heating element for heating fuel in said fuel line immediately upstream of said filter means to a temperature below the vaporization point to avoid filter-clogging deposits in said filter means, means for sensing the temperature of fuel in said fuel tank, and an electric circuit supplying current from said battery and alternator to said heating element, said circuit including first switch means controlled by said temperature sensing means, manually controllable second switch means connected in series with said first switch means and third switch means connected in parallel with second switch means and controlled by said alternator to be closed when said alternator is producing voltage to supply current to said electric heating element to heat the fuel only when the temperature of fuel in said fuel tank is below a predetermined value and at least one of said second switch means and third switch means is closed.

Claim 10

In a fuel system for a diesel internal combustion engine of a vehicle having a storage battery and an alternator supplying current to said battery, said system comprising fuel injection nozzles, pump means for supplying liquid fuel under pressure to said injection nozzles, fuel filter means upstream of said pump means for filtering fuel supplied to said pump means, a fuel tank and a fuel line connecting said fuel tank with said filter means, the improvement comprising an electric heating element for heating fuel in said fuel line immediately upstream of said filter means to a temperature below the vaporization point to avoid filter-clogging deposits in said filter means, means for sensing the temperature of fuel in said fuel tank, and an electric circuit supplying current from said battery and alternator to said heating element, said circuit including first switch means controlled by said temperature sensing means, manually controllable second switch means connected in series with said first switch means and third switch means connected in parallel with second switch means and controlled by said alternator to be closed when said alternator is producing voltage to supply current to said electric heating element to heat the fuel only when the temperature of fuel in said fuel tank is below a predetermined value and at least one of said second switch means and third switch means is closed.