AU2006100904A4 - Electric element fuel line heater assembly - Google Patents

Description

Page 1 CN1 ELECTRIC ELEMENT FUEL LINE HEATER ASSEMBLY SThis invention relates to improvements in Electric Element Fuel Line Heaters primarily used to Z retrofit diesel engines for use as a multiple fuel capable diesel engine. This invention assists with Sstarting on, and continuous operation using vegetable oil as fuel in diesel engines.

With the looming fuel shortages and increasing prices of diesel fuel, people are looking for Ssubstitute or alternative fuels to operate their vehicles, generators and equipment.

The diesel engine was originally designed by Rudolf Diesel to run on vegetable oil, and later evolved to run primarily on mineral fuels. Today's diesel engines are not designed to operate on vegetable oil without modification to either the oil or the engine. Most people modify the oil into a 0 thinner fuel called fatty acid methyl esters, otherwise known as Biodiesel. Many people make N alterations to the fuel systems of their diesel engines to be multiple fuel capable, allowing them to run on either Biodiesel, Petroleum Diesel, Vegetable Oil or Waste Vegetable Oil.

Essentially the conversion requires that the viscous vegetable oil fuel is heated prior to the injector pump to make it less viscous reducing strain on the pump, and heated to a minimum of 70 0 c before the injectors to ensure that the fuel atomizes properly to limit engine damage and improve burning, reducing exhaust gasses.

The existing similar product to my invention available on the market is one continuous length of nickel chromium wire, sheathed in a woven fiberglass sock. The common term for such a product is a heat trace, and they are commonly found in refrigeration systems and for anti-icing in air cooling systems etc.

The existing product requires the end user to lag the heat trace onto the fuel lines by binding with a supplied self amalgamating high temperature silicone tape and electrically insulating any open areas of the woven fiberglass sock with an end user sourced high temperature liquid silicon, making for a tedious and potentially messy installation, with several hours waiting time between lengthy installation steps.

The existing similar product is not supplied with any thermal switching device, or instructions for connecting such, allowing the heating element in my trials to reach temperatures well above 180 0 c, placing heat stress on the fuel line and potentially overheating either the fuel or the element, and has the potential to ignite volatile substances that may be found in the engine compartment. The element is not adequately thermally insulated against outside atmosphere, in fact the fiberglass sock acts to insulate the element from the fuel line that the element is trying to transfer heat to, and can easily short out to the fuel lines due to difficult installation procedures causing improper installation leading to product failure or possible fire.

My invention ensures that the fuel is at an optimum temperature prior to the injector without placing undue heat stress on the fuel lines and using a minimum of energy. My invention can also Page 2 i be used safely at other places on the fuel line where heat transfer is required.

O One example of my invention consists of a series of electrically insulated flexible heating elements Z wound around the fuel injector line(s) operating off a thermostat switching off at 90 0 c and back on Sat 75 0 c to offer a mearrn-emperature of 82'c. The thermostat could be allowed to operate at different temperatures depending on fuel flow and other factors. The elements are electrically insulated to protect them from shorting to earth on the fuel lines, and the assembly is thermally Sinsulated to protect from both heat loss and air cooling. The assembly components have been C designed or chosen for their ability to be installed by an unskilled end user.

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The product relies on the thermal conductivity of the fuel line to transfer the heat generated by the 0, element to the fuel in an effort to heat the fuel to between 70 0 c to 80 0 c at the injector nozzle to C assist with fuel atomization to offer a clean burn.

The assembly consists of several components in combination; Flexible heating elements, thermal switching device and a thermal insulation.

The flexible heating elements in this example are manufactured from a Nickel Chromium Resistance Wire electrically insulated by a 1.5mm Diameter Silicone Coated High Temperature Sleeve. This has a female Bullet Terminal Crimped to each end. The flexible elements could be constructed of other materials with the intent being to generate heat quickly to transfer to the fuel lines.

The flexible heating element is loosely wound around each fuel injector line, starting at the injector end close to the injector and working back. The heating elements are then electrically linked together in series by high temperature resistant connecting cables with a male bullet connector crimped to each end, pushed into the female connectors on the heating elements. Varying lengths of elements and connecting cables can be made up for individual requirements, and the heating elements could be constructed using a variety of styles of connectors.

A thermal switching device is fastened to one of the heating elements. This example uses a thermoswitch clamped to the fuel line over the heating element by means of a cable tie, and positioned to be in contact with the heating element, but could use a variety of other fixing or clamping methods.

One end of the series of heating elements is connected to earth, the other to an active power supply via a relay which is activated by the thermal switching device.

The assembly is thermally insulated with materials that will be unaffected at temperatures of up to 120 0 c, and offer resistance to petrochemicals, as the elements can reach these temperatures on activation.

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c- This example of the invention makes use of a fire retardant polypropylene flexible split sleeve tubing otherwise known as a loom tube to cover the heating elements that are wound around the 0 fuel line. This rigid tube allows for the connectors to protrude out from the split in the tube. The Z tube is then further insulated with a self sealing specialist fire rated non-porous closed cell CC elastomeric foam with-a-wall thickness of 9mm and an inside diameter of 12mm when sealed, which provides both an insulative cover and barrier to water and vapour.

To assist with understanding the invention, reference will now be made to the following illustrations which show one example of the invention.

In the drawings: Figure 1 shows one example of how the thermostat may be mounted to the heating element.

c-i Figure 2 shows one example of a cut away model of one completed assembly in the array.

Referring to Figure 1, the heating element (11) is made up from a male bullet connector (1,4) pressed into a female Bullet connector which is crimped onto a silicone sleeve covered resistance wire.

The heating element (11) is wound around the metal fuel line with the connectors left protruding vertically to the fuel line for wiring.

A thermostat (10) is placed over the loops of the heating element The thermostat housing (8) is secured in place by use of a cable tie looped through the eyes of the housing The male spade connectors on the thermostat are left standing vertical to the assembly for wiring.

Referring to Figure 2 which illustrates a cut away model of the assembly, the heating element (11) as previously described is wound around the fuel line A fire retardant polypropylene flexible split sleeve tubing (13) is slipped over the wound heating element with the connectors left protruding out through the split The assembly is then further insulated with a self sealing fire rated non-porous closed cell elastomeric foam The connectors are left protruding out through the join The foam is self sealing (15) allowing for an easy installation.

The heating element assemblies are installed to each fuel injector line just prior to the injectors, with installation of only one thermal switching device being necessary. The assemblies are then wired in series with one end being power activated by the thermostat and the other wired to earth.

It will be realized that the Electric Element Fuel Line Heater Assembly according to this invention is not restricted to the form shown in the examples, but may use other thermal switching devices, heating element components, insulative materials or electrical connectors.

Claims (1)

1. 3. The assembly as of claim 1 wherein the heating elements are controlled by a thermal switching IN device to avoid overheating. C1 4. The assembly as of claim 1 wherein the heating elements are thermally insulated from atmospheric cooling. An Electric Element Fuel Line Heater substantially as herein before described with reference to figures 1 and 2 of the accompanying drawings. Marcus Deuchar 22 October 2006