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Worlds Best Heat exchanger- Supplied To Ford, by International (via Caterpillar)

So what exactly does that mean? I am referring to the HEUI method of diesel fuel injection of course. HEUI stands for Hydraulically Actuated Electronically controlled Unit Injector. This new method of injection was originally developed by Caterpillar back in the late 80's. International quickly adopted this new technology (at the time) and employed it in several of it's own engines including the T444E which is the International version of the 7.3L PSD, and their big brother the DT466.

Unlike most conventional diesels of the current and past, the PSD has no injection pump. Already that is a huge advantage for WVO. High pressure engine oil is used to create the massive injection force to inject the fuel directly into the cylinder at up to 21,000 psi. This high pressure oil is supplied by the engine oil pump to a reservoir on the top front of the motor. This reservoir is what your PSD decorative cover bolts to. That reservoir then feeds a High pressure Oil pump that sits directly below your OEM fuel bowl. This pump is drive by a chain from the camshaft and pressurizes the oil from 600 to 3000 psi. That pressure is then fed to the high pressure side of the injector. Now on the fuel side, things are more standard. Fuel is fed to the injectors at a more conventional 50-75 psi through fuel rails that are physically cast into the head (see picture below). This is the other part that works so well for WVO. The fuel actually has to go into and through the head before ever reaching the injector. Each fuel rail only holds about 2 oz of fuel (not counting what is in the injector) which is a very small volume relative to the motor size. This means that the fuel either collects or gives up it's heat very quickly. So bottom line is that regardless of what the fuel temp is going into the motor, by the time it reaches the injectors, it will be engine temperature. And that is why I stress the temperature of the engine far more than the temperature of the oil.

So now that your injector has fuel, and high pressure oil, there is only one more input needed. That is where the electronically actuated part comes in. The computer sends a signal to the injector and activates a solenoid. When the injector is in between firings, the fuel passage is open allowing it to "fill" with fuel. Then the computer activates the solenoid and allows the High pressure Oil in, and blocks the fuel from escaping. Now that High pressure oil (up to 3,000 psi) pushes on an intensifier piston that multiplies that force x7 times.

So why do I keep saying "up to 3,000 psi"?  That is another control the computer uses to control injection timing and volume. Solenoid pulse width staying the same, if the computer reduces the HPO to only 1000 psi, less fuel will be injected over the same period of time. Or the PW can be shortened and the pressure increased to inject the same amount of fuel at a different timing curve, say more advance. The variations are nearly limitless, but you get the idea, or are thoroughly confused by now..

Dino Fuel Alternatives Technical Bulletins are available for download in .pdf format.  You will need to have Adobe Reader installed in order to view or print these documents.  Click on the Adobe Reader image below to download the most recent version of Adobe Reader for FREE from the Adobe website.