Originally Posted by nrichter1984

Also, in a gas engine the air/fuel is ignited with a spark and a diesel engine it's ignited by the heat created from compressing the volume of air in the cylinder. An injector in a diesel engine is required to time, meter and increase fuel pressure.

As zhilton said, nozzle opening pressure is usually around 3000 psi and increases during the duration of injection. A gas injector is usually around 30-50 psi and the fuel pump/regulator dictates injection pressure. A HUEI injector uses a high pressure oil pump that increases oil pressure in the injection circuit and acts on an amplification piston in the injector, which turns 500 psi of oil pressure into 6000 psi of fuel pressure. The timing, beginning and end of injection, in a HUEI system is infinitely adjustable by the engine ECM, which controls the opening and closing of the oil solenoid in the injector, allowing oil to act on the amplification piston and direct it away. The metering of fuel is controlled by the engine ECM, which controls the opening and closing of the solenoid in the injector fuel circuit, allowing the required amount fuel to enter the injector. A gas injector is basically a solenoid that opens and closes to allow fuel into the intake manifold at the correct time and orifii to atomize the fuel to mix with the incoming air.

The high fuel pressure and very small orifii in a diesel fuel injector nozzle are required to atomize the fuel fine enough to allow for quick and complete vaporization of the fuel once it is injected, so the heat created by compression can ignite it (diesels don't have a spark to ignite the fuel).

A diesel fuel injector also has to withstand combustion pressure as most modern diesel engines are direct injection, meaning the injector injects directly into the combustion chamber. Whereas, until recently, most gas engines inject the fuel into the intake manifold upstream of the intake valve to mix with the incoming air.

Originally Posted by bismic

FYI the intensifier piston in our injectors is a 7:1 design. 500 psig in the HP oil (min) becomes 3500 fuel pressure, 4000 psig in the HP oil (max) becomes 28,000 fuel psig (and the FICM is responsible for the spool valve operation).

Originally Posted by nrichter1984

I was just making a generic statement to get my point across . I'm used to working on caterpillar engines and based that point of my statement on specs from a cat engine. I don't know the 6.0L specific specs since I don't usually work on internationals and have only recently started.

Originally Posted by nrichter1984

I was just making a generic statement to get my point across . I'm used to working on caterpillar engines and based that point of my statement on specs from a cat engine. I don't know the 6.0L specific specs since I don't usually work on internationals and have only recently started.