Question about injection systems
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Elder User
Joined: Apr 2006
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From: Edmonton, AB
Question about injection systems
I am just looking for some information about Diesel Fuel injection systems because primarly I am intersted in this stuff and want to educate myself. I know the 6L uses oil injection system (HPOP?) as do Cat engines. The 6.4L will use piezo electric (same as duramax). What is cummins using? what about the old 7.3L? Are there any types other than these and the old mechanical pumps. Finaly it seems that the 6L system is what makes the powerstrokes run like **** (when they do run poorly) why did Ford ever go with it?
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Joined: Jul 2005
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From: 21791
cummins uses a Pressure Time (PT) fuel system on their bigger engines like the N10(?). there is a lift pump that pushes fuel to a main pump that pressurizes the fuel in the heads to around 400PSI on a stock engine. when the injector spill ports open up, the fuel flows into the barrel and the injector is fired via the cam. at least the one at school is like that. the PT systems is unique to cummins.
the cummins with Injection Pumps (like the mechanical 5.9 ISB's) use a multi-plunger injection pump that is run off the cam via a gear. the pressure-making part of the injector are put in a row into a pump, with a cam that has lobes on it that runs below all of the plungers that pressurize fuel. as the cam spins, the lobes rotate around and push up on the plungers which then pressurize fuel. out of the top of each plunger you will see a steel line (all of equal length) that go to injector nozzles in the cylinder head(s). the fuel is already pressurized for the nozzles, so all the nozzle's job is to atomize the fuel into a fine smoke and deliver the fuel when it is sent to it. these are not unit injectors because the pressurizing and metering parts of the injection system are not contained in one unit..(injector barrel/plunger and the nozzle)
all Powerstrokes (94.5-2007) use HEUI (Hydraulic actuated Electronic fired Unit Injectors. the term "Unit Injector" means that the pressuizing and metering parts are all contained in one unit. so once fuel is fed to the injectors at low (50-100psi) pressure, they will pressurize the fuel upwards of 21,000psi and meter it at the correct time. the HEUI's are a little more complicated, they use a High Pressure Oil Pump (HPOP) that uses the engine's lubricating oil. the pump pressurizes oil from 500psi at idle to 3000+psi at full output. the oil is then put through the oil galleries in the heads that go into the injector. electronic control allows the oil to flow in at predetermined times. the super-pressurized oil pushes down in an intensifier piston that then pressurizes the fuel to the 21,000psi. to do this the intensifier piston has to be much larger (relatively) than the injector plunger that compresses the fuel). once the fuel is pressurized it lifts the needle off of it's seat and the fuel is atomized and squirted into the cylinder.
with the exception of the C7 (HEUI), most caterpillar engines use cam-fired injectors. some of the older mechanical engines such as the 3406 series use injection pumps and nozzles in the head like the cummins i described above.
i have not learned about the piezo electric injection yet, nor about the duramax fuel system. i believe the 6.4 will be common rail?
actually International makes the engines for the Ford trucks. the T444E is the 7.3L powerstroke and the VT365 is the 6.0L powerstroke. the VT275 is the little 4.5L compound turbo in the LCF Ford trucks.
the cummins with Injection Pumps (like the mechanical 5.9 ISB's) use a multi-plunger injection pump that is run off the cam via a gear. the pressure-making part of the injector are put in a row into a pump, with a cam that has lobes on it that runs below all of the plungers that pressurize fuel. as the cam spins, the lobes rotate around and push up on the plungers which then pressurize fuel. out of the top of each plunger you will see a steel line (all of equal length) that go to injector nozzles in the cylinder head(s). the fuel is already pressurized for the nozzles, so all the nozzle's job is to atomize the fuel into a fine smoke and deliver the fuel when it is sent to it. these are not unit injectors because the pressurizing and metering parts of the injection system are not contained in one unit..(injector barrel/plunger and the nozzle)
all Powerstrokes (94.5-2007) use HEUI (Hydraulic actuated Electronic fired Unit Injectors. the term "Unit Injector" means that the pressuizing and metering parts are all contained in one unit. so once fuel is fed to the injectors at low (50-100psi) pressure, they will pressurize the fuel upwards of 21,000psi and meter it at the correct time. the HEUI's are a little more complicated, they use a High Pressure Oil Pump (HPOP) that uses the engine's lubricating oil. the pump pressurizes oil from 500psi at idle to 3000+psi at full output. the oil is then put through the oil galleries in the heads that go into the injector. electronic control allows the oil to flow in at predetermined times. the super-pressurized oil pushes down in an intensifier piston that then pressurizes the fuel to the 21,000psi. to do this the intensifier piston has to be much larger (relatively) than the injector plunger that compresses the fuel). once the fuel is pressurized it lifts the needle off of it's seat and the fuel is atomized and squirted into the cylinder.
with the exception of the C7 (HEUI), most caterpillar engines use cam-fired injectors. some of the older mechanical engines such as the 3406 series use injection pumps and nozzles in the head like the cummins i described above.
i have not learned about the piezo electric injection yet, nor about the duramax fuel system. i believe the 6.4 will be common rail?
Finaly it seems that the 6L system is what makes the powerstrokes run like **** (when they do run poorly) why did Ford ever go with it?
