Ford's answers to the NHTSA 6.7 Investigation

NinerBikes wrote:
This one is the mother lode of all that I've come across, it's got complete sensor and feedback loops for Bosch's state of the art piezo injectors and pollution controls... which makes me wonder if that last fuel stroke by the nozzle for exhaust DPf cleaning with the heat is the coupe de grace for fuel flow on this HPFP.

http://www.dsd.go.th/itrain/km/kboc/2010_TestProject_WSC40/Automobile/DOC33_IL_40CA/DOC33_IL_40CA_1680_Diesel_Engine_2.0L_TDI_CommonRail_BIN5_UL.pdf

Ben etc:

Have a look at page 34-36 of this pdf.

Someone... file this away before someone takes it down.

If you look at the fuel flow, there are 2 micro filters that filter fuel before it gets into the common rail.

What if the filter plugs?



One on the return line switch, the other on the intake port for the high pressure compression.


The immediate thought that comes to mind is a lot of fuel is bled off back to the tank for cooling the cam / roller / piston.


Look at the Fuel Metering Valve N290 on p. 34 right on the fuel pump.

It looks like it is actively controlled.

That is, if pressure is excessive, that valve should shut to stop the flow.

There a return line from the common rail.

Return from common rail is modulated by N276 p. 40.


Why do they basically have 2 modulators? One at the pump and one at the common rail to measure pressure?

Couldn't they modulate pressure at one place and be done with it?


Note there is a pressure sensor at the opposite end of the rail.

On the 6.7, is that only done on one rail (sensor and modulator) or are both rails similarly monitored / modulated?

rickatic question!!!


Where is (if there is) a return for the injectors?



Right off the bat --- we may have a software problem as well as an actuator problem.

2 ECM controlled modulators, one at pump, one at end of rail.

One pressure sensor at tend of common rail.

Hmmmm



rick.. note that VW implemented the Cylinder pressure sensor that Ford and I think GM chose not to do.