Ford's answers to the NHTSA 6.7 Investigation

Paper directly relevant to the Ben hypothesis:


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Performance Analysis of Rail-Pressure Supply Pumps of Common-Rail Fuel Systems for Diesel Engines
Number: 2005-01-0909

Published: 2005-04-11


DOI: 10.4271/2005-01-0909
Author(s): Ho Teng - AVL Powertrain Engineering, Inc.; James C. McCandless - AVL Powertrain Engineering, Inc.
Citation:
Teng, H. and McCandless, J., "Performance Analysis of Rail-Pressure Supply Pumps of Common-Rail Fuel Systems for Diesel Engines," SAE Technical Paper 2005-01-0909, 2005, doi:10.4271/2005-01-0909.


Citation

Abstract:

This paper discusses the performance of the radial plunger pump used in the contemporary diesel common-rail fuel systems for rail-pressure supply. On the ground of the pump mechanism, the transient flow, drive torque, and efficiency of the pump are analyzed for various operation conditions. The analysis shows that the number of plungers and utilization of the pump capacity govern fluctuations in the pump discharge. The pump flow can be characterized by a discharge function which applies to both full- and part-capacity pump flows. At the full pump capacity, the discharge fluctuation is determined solely by the number of plungers: a pump with an odd number of plungers has more ripples and lower amplitudes in its discharge than a pump with an even number of plungers does. A pump operates at a part capacity has more fluctuations in the discharge than when at the full capacity. If the pump speed is not very low, then a critical flow exists for any given pump speed, at which the pump discharge becomes fully pulsatile and increase in the pump speed will lead to a discontinuous pump flow, which generates pressure fluctuations in the common rail. This pump discharge induced rail-pressure fluctuation becomes significant when the engine is operated with a multiple-injection strategy: large rail-pressure fluctuations may result in a poor control in the non-primary injections. To mitigate the effect of the rail pressure fluctuation on injections, the pump size and the volume of common rail should be designed according to both the engine fuel demands and the injection control strategy.
References:

Bosch, Diesel Accumulator Fuel-Injection System Common Rail, Robert Bosch GmbH, 1999.
Shinohara, Y. and Toyao, T., “Japanese Experience in the Common Rail Fuel Injection Technology,” ATA International Symposium on the Future of Diesel Engine Technology for Passenger Cars, Paper No. 20A2015, 2000.
Leet, J.A., Simescu, S., Froelund, K., Dodge, L.G. and Roberts, C.E., “Emissions Solutions for 2007 and 2010 Heavy-Duty Diesel Engines,” SAE Paper, No. 2004-01-0124.
Park, C. Kook, S., and Bae, C., “”The Effect of Multiple Injections in a HSDI Diesel Engine Equipped with Common Rail Injection System,”, SAE Paper No. 2004-01-0127, 2004.
Bosch, Diesel Engine Management, Robert Bosch GmbH, 3rd ed., 2004.
Hadekel, R., Displacement pumps and motors, Sir Isaac Pitman & Sons, ltd., London, 1951.
Stringer, J., Hydraulic Systems Analysis: An Introduction, John Wiley & Sons, N.Y., 1976.
Yeaple, F., Fluid Power Design Handbook, 3rd ed., Marcel Dekker, Inc., N.Y., 1996.
Burman, P.G. and DeLuca, F., Fuel Injection and Controls for Internal Combustion Engines, copyright by Burman Paul. G. and DeLuca Frank, Library of Congress Catalog Card Number: 62-12020, printed in USA, 1962.
McCandless, J.C., Teng, H. and Schneyer, J.B., “Development of a Variable-Displacement, Rail-Pressure Supply Pump for Dimethyl Ether,” SAE Paper, No. 2000-01-0678, 2000.

This paper should apply to the pump valve...

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Cavitation Behaviour of Hydraulic Orifices and Valves
Number: 982038

Published: 1998-09-14


Publisher: SAE International

Language: English
DOI: 10.4271/982038
Author(s): T. S. Koivula - Institute of Hydraulics and Automation, Tampere University of Technology, Finland; A. U. Ellman - Institute of Hydraulics and Automation, Tampere University of Technology, Finland
Citation:
Koivula, T. and Ellman, A., "Cavitation Behaviour of Hydraulic Orifices and Valves," SAE Technical Paper 982038, 1998, doi:10.4271/982038.


Citation

Abstract:

Cavitation is a common and usually undesirable phenomenon in hydraulic systems. Understanding the basics of cavitation phenomenon as well as detecting existing cavitation are important in order to prevent cavitation in hydraulic systems.

In this paper past studies of orifice cavitation are discussed and also new studies of orifice and valve cavitation with hydraulic oils are presented.

Cavitation behaviour of different kinds of orifices and a poppet valve have been studied. Studies were done with different cavitation numbers.

Rough design guidelines for reducing and preventing cavitation in orifices and valves are presented.
References:

Berger, J. 1982. Untersuchung der Auswirkung von Kavitation beim Einsatz von HFA-Flüssigkeiten. O+P “Ölhydraulik und Pneumatik” 26 Nr.6. pp. 441-451.
Kleinbreuer, W. 1979. Untersuchungen der werkstoffzerstörung durch Kavitation in ölhydraulischen Systemen. Dissertation TH Aachen.
Lamb, W.S. 1987. Cavitation and Aeration in Hydraulic Systems. Cranfield, BHR Group Limited.
Maeda, T., Sato, S. 1989. Erosion of Poppet Valve Chambers by High Water Content Fluid. International Symposium on Fluid Power. Tokio. JHPS. pp. 267-273.
McCloy, D., Martin, M.R. 1973. The Control of Fluid Power. London, Longman Group Limited.

How are additives validated as "harm free"?

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Protecting Diesel Fuel Injection Systems
Number: 2011-01-1927

Published: 2011-08-30


JSAE Technical Paper No. 20119110

Publisher: SAE International

Language: English
DOI: 10.4271/2011-01-1927
Author(s): Rinaldo Caprotti - Infineum UK; Nadia Bhatti - Infineum UK; Ishibe Nobuyuki - Infineum Japan
Citation:
Caprotti, R., Bhatti, N., and Nobuyuki, I., "Protecting Diesel Fuel Injection Systems," SAE Technical Paper 2011-01-1927, 2011, doi:10.4271/2011-01-1927.


Citation

Abstract:

Diesel fuel injector deposits have been observed in the field for many years. Their location and composition is dependant on the type of Fuel Injection Equipment (FIE) technology utilised in vehicles and fuel quality. This paper first characterises such deposits and then defines the maximum acceptable level to ensure best field performance for the following FIE systems: InDirect Injection (IDI), High Pressure Common Rail (HPCR) and Electronic Unit Injection (EUI).

HPCR has been instrumental in achieving the lowest possible emissions and Fuel Consumption (FC) levels. It is now the only choice for new Passenger Car (PC) applications meeting Euro 5, US Tier 2 and Japan Post New Long Term emission regulations. Its use is also increasing in Heavy Duty (HD) applications. However, HPCR and EUI have both been shown to have a tendency to form injector deposits that can negatively impact emissions, power and fuel consumption. This has been confirmed in a variety of tests ranging from industry recognised bench engine tests to bench engine tests run in co-operation with OEMs and field programmes.

The data developed show that appropriate Deposit Control Additive (DCA) technology can prevent and restore the FIE to its optimum operating conditions. This has been confirmed using a mix of reference and market relevant fuels.

Any fuel additive solution should be harm free in field applications. Therefore, the DCA technology utilised in this paper has been validated through a series of robust harms tests that include a mix of standard industry tests, in house tests and field trials at elevated treat rates.
References:

Dober, G., Tullis, S., Greeves, G., Milovanovic, N., Hardy, M., and Zuelch, z., “The Impact of Injection Strategies on Emissions Reduction and Power Output of Future Diesel Engines,” SAE Technical paper 2008-01-0941:,
Carton, L. et al, “EU5 und danach: Integriertes Management von Verbrennung und Abgas bei PKW Common-Rail Dieselmotoren,” 13. Aachener Kolloquium Fahrzeug- und Motorentechnik, 2004.
Egger, k.Dr., Warga, J., Klügl, W., “Neues Common-Rail-Einspritzsystem mit Piezo-Aktorik für Pkw-Dieselmotoren,” published in MTZ 2002-09.
Ullmann, J., Geduldig, M., Stutzenberger, H., Caprotti, R., Balfour, G., “Effects of Fuel Impurities and Additive Interactions on the Formation of Internal Diesel Injector Deposits,” TAE Esslingen Symposium, 2009.
Panesar, A., Martens, A., Jansen, L., Surag, L., Ray, D., Twillwy, M., “Development of a new Peugeot XUD( 10 hour cyclic test to evaluate the nozzle coking propensity of diesel fuel,” SAE 2000-01-1921.
Graupner, O., Klaua, T., Caprotti, R., Breakspear, A., Schik, A., Rouff, C., “Injector Deposit Test for Modern Diesel Engines,” TAE Symposium, 2005.
Caprotti, R., Breakspear, A., Graupner, O., Klaua, T., Kohnen, O., “Beyond 2008: The Challenges for Diesel Detergency,” TAE Symposium 2007.
Caprotti, R., Bhatti, N., Tang, T., Chew, W K., “Flexible Solutions to Control Direct Injection Deposits in Asia Pacific,” 15th Annual Fuel and Lubes conference.
DieselNet, “Emission Test Cycles,” http://www.dieselnet.com.proxy.lib.uwaterloo.ca/standards/cycles/ece_eudc.html
Tang, J., Pischinger, S., Lamping, M., Körfer, T. et al., “Coking Phenomena in Nozzle Orifices of Dl-Diesel Engines,” SAE Int. J. Fuels Lubr. 2(1):259-272, 2009, doi:10.4271/2009-01-0837.

A Method for the Estimation of the Service Life of a Precision Guiding Interface “Needle - Nozzle Body” of a Common-Rail-Injector for High Rail Pressures
Number: 2011-01-2020

Published: 2011-08-30


JSAE Technical Paper No. 20119087

Publisher: SAE International

Language: English
DOI: 10.4271/2011-01-2020
Author(s): Vladislav E. Lazarev - South Ural State Univ.; Vladislav E. Lazarev - South Ural State Univ.; Johann A. Wloka - South Ural State Univ.; Georg Wachtmeister - South Ural State Univ.
Citation:
Lazarev, V., Lazarev, V., Wloka, J., and Wachtmeister, G., "A Method for the Estimation of the Service Life of a Precision Guiding Interface “Needle - Nozzle Body” of a Common-Rail-Injector for High Rail Pressures," SAE Technical Paper 2011-01-2020, 2011, doi:10.4271/2011-01-2020.


Citation

Abstract:

The analysis of type and form of the loading in the guidance between the needle and body of a CR-injector, as well as the transformation of friction energy on the contact surfaces which absorbs mechanical and thermal loads with deforming and heating the contact layer is presented. The dominant parameters of friction and wear for the investigated interface (radial force, mode of friction, relation for the nominal and real contact areas etc.) are shown in function of different values of rail pressures, varying from 500 to 3000 bar. A special coefficient of accumulation of energy is defined. With these coefficient the analysis of thermal- and stress-conditions for the precision tribosystem become possible. Furthermore this leads to the calculation of the intensity of wear for the mentioned components of the nozzle. The estimation of the service life for the guidance is performed for different values of rail pressures, considering the limit values of wear for the components of the nozzle and of a gap in the contact interface.

Cavitation simulations...

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Nozzle Flow and Cavitation Modeling with Coupled 1D-3D AVL Software Tools
Number: 2011-24-0006

Published: 2011-09-11




Publisher: SAE International

Language: English
DOI: 10.4271/2011-24-0006
Author(s): Valdas Caika - AVL LIST GmbH; Peter Sampl - AVL LIST GmbH
Citation:
Caika, V. and Sampl, P., "Nozzle Flow and Cavitation Modeling with Coupled 1D-3D AVL Software Tools," SAE Technical Paper 2011-24-0006, 2011, doi:10.4271/2011-24-0006.


Citation

Abstract:

The paper is devoted to the coupled 1D-3D modeling technology of injector flow and cavitation in diesel injections systems. The technology is based on the 1D simulation of the injector with the AVL software BOOST-HYDSIM and 3D modeling of the nozzle flow with AVL FIRE. The nozzle mesh with spray holes and certain part of the nozzle chamber is created with the FIRE preprocessor. The border between the 1D and 3D simulation regions can be chosen inside the nozzle chamber at any position along the needle shaft. Actual coupling version of both software tools considers only one-dimensional (longitudinal) needle motion. Forthcoming version already includes the two-dimensional motion of the needle. Furthermore, special models for the needle tip contact with the nozzle seat and needle guide contact with the nozzle wall are developed in HYDSIM. The co-simulation technology is applied for different common rail injectors in several projects. It proved to be an efficient and user-friendly engineering tool. An example of piezoelectric common rail injector with a minisac nozzle is presented. Based on it, different numerical and technical aspects of the nozzle flow and cavitation modeling are discussed.
References:

Alajbegovic, A., Greif, D., Basara, B. and Iben, U., Cavitation Calculation with the Two-fluid Model, 3rd European-Japanese Two-phase Flow Group Meeting, Certosa di Pontignano, Italy, September 2003.
Arcoumanis, C., Flora, H., Gavaises, M., and Badami, M., “Cavitation in Real-Size Multi-Hole Diesel Injector Nozzles,” SAE Trans. J. of Engines, 109,2000, doi:10.4271/2000-01-1249.
AVL BOOST HYDSIM, User's Guide, Graz 2010.
AVL FIRE, Eulerian Multiphase, Graz 2010.
Boecking, F. et al., Passenger Car Common Rail Systems for Future Emissions Standards, MTZ 7-8/2005, Vol. 66, 552-557.
Chen, Y. and Heister, S.D., Modeling Cavitating Flows in Diesel injectors. Atomization and Sprays, 1996, Volume 6, 709-726.
?aika, V., Kammerdiener, T., and Dörr, N., “Operation of Piezoelectric Common Rail Injector with Diesel and FT-Kerosene,” SAE Technical Paper 2007-24-0070, 2007, doi:10.4271/2007-24-0070.
?aika, V., Sampl, P., Tatschl, R., Krammer, J. et al., “Coupled 1D-3D Simulation of Common Rail Injector Flow Using AVL HYDSIM and FIRE,” SAE Technical Paper 2009-24-0029, 2009, doi:10.4271/2009-24-0029.
Drew, D.A. and Passman, S.L. Theory of Multi-component Fluids, Springer, New York, 1998.
Ishii, M. Thermo Fluid Dynamic Theory of Two-Phase Flow, Eyrolles, Paris, 1975.
Giannadakis, E., Gavaises, M. and Arcoumanis, C., Modeling of Cavitation in Diesel injector Nozzles, J. Fluid Mechanics, 2008, 616, 153-193.
Payri, F., Margot, X., Patouna, S., Ravet, F. et al., “A CFD Study of the Effect of the Needle Movement on the Cavitation Pattern of Diesel Injectors,” SAE Technical Paper 2009-24-0025, 2009, doi:10.4271/2009-24-0025.
Sun, X., Kim, S., Ishii, M. and Beus, S. Modeling of Bubble Coalescence and Disintegration in Confined Upward Two-phase Flow, Nuclear Engineering and Design, 230, 3-26, 2004.
Wang, D.M. and Greif, D., Progress in Modeling Injector Cavitating Flows with a Multi-fluid Method. FEDSM2006-98501, ASME Forum on Cavitation and Multiphase Flow, Miami, FL, USA, July 2006.
Wang, D.M. et al., Interfacial Area and Number Density Transport Equations For Modeling Multiphase Flows with Cavitation, Proc. ASME 9th Int. Symposium on Gas-Liquid Two-Phase Flow, FEDSM'05, Houston, Texas, USA, June 2005.
Schmidt, D.P. and Corradini, M.L., The Internal Flow of Diesel Fuel injector Nozzles. Int. J. Engine Research, 2001, 2, 1-22.
Sou, A., Kinugasa, T., Numerical Simulation of Developing Cavitating Flow in a Nozzle of Pressure Atomizer, THIESEL 2010 Conference on Thermo- and Fluid Dynamic Processes in Diesel Engines, Valencia, Spain, September 2010.
Yuan, W. and Schnerr, G.H., Cavitation in Injection Nozzles: Effect of Injection Pressure Fluctuations, Proc. 4th Int. Symposium on Cavitation, Pasadena, CA, USA, 2001.

A big accumulator is a negative in many ways, from keeping fuel in it that is in a hot place, pressurized.

Low volatility of diesel mean low fire risk, but still, don't want that big pot squirting out at 2,000 bar.

At that pressure, it will go through many things, thick gauge steel, shoot through a body.

I can understand why using a common rail to also be accumulator --- changing the common rail to a larger diameter is a relatively simple design change, with significant costs, plus also time before it fully pressurize on start.

Still am not sure if the issue is accumulator / dampening -- vs. cavitation at the low end of the pump, or coating ablation.


One way to play around with the accumulator ( a die cast part, from what it seems) is to add odd shapes / baffles in it to alter its wave properties.

Again, need a good simulation, but once it is done --- shouldn't add more than marginally to the cost --- maybe 20 euro cents or so per unit for some extra metal, one time tooling charges to shape the die.

BenK wrote:
New thought on Greg's info...Alu is sacrificial to Fe...if there are Fe oxide
from rusty tanks...some might get through the protection filters and why need
to know what those filter down to

Would those Fe oxide particles then adhere to the pump body innards to then
create more debris via galvanic action between those two

Catalyst ?

I believe, at least in VW / Audi applications, it is down to 10 micron, not sure the trap rate, 65 to 95% first pass? I do know that where I buy fuel, Conoco deliver guy has told me that all of their fuel is filtered down to 2 micron spec at the refinery. How clean it stays the rest of the trip to the station where I fill up is another matter.

New thought on Greg's info...Alu is sacrificial to Fe...if there are Fe oxide
from rusty tanks...some might get through the protection filters and why need
to know what those filter down to

Would those Fe oxide particles then adhere to the pump body innards to then
create more debris via galvanic action between those two

Catalyst ?

NinerBikes wrote:
snip...

Ben, 2 lobe cam driving 2 pistons, like a harley davidson V, gives you four HPFP fuel compression strokes per rpm... and since this is a 4 stroke motor, the power cycle for all 8 cylinders takes 2 revolutions of the crank. So you get 8 pump pulses from the pump. 8 cylinders, 8 pulses, pump is driven 1:1 by gear drive on the Ford, belt drive on the Audi VW in line 4.

Okay, got it and that makes sense. Had thought single cam and
two followers and the wacky stuff they would have had to do that
Didn't see two cam lobs in the videos, but those videos are
marketing not technically targeted

IT also bolsters the cavitation speculation, as why would they need/want
to time it to the injectors?

Can only think of issues at the injectors and then that a big accumulator
would have solved that

Thanks

NewsW wrote:
Time to throw in the towel on conventional Diesels?

snip...

First, repeat that I'm not a diesel guy...was looking but saw the
emissions stuff coming down the track and a wreck for a decade or more

I like the new injector technology, but dislike the rest of the
new 'gasser' metrics of these new systems dictated by the herd jumping
into diesel 'king of the hill' marketing metrics

Personally love low RPM, high torque ICE's...especially big block gassers

I'd consider diesel if it was more conventional than new higher RPM versions

I'd use the piezo injectors with PWM controllers at low RPM with high
torque characteristics

Since PWM...first squirt to get it going before TDC, which would raise
the PSI higher (advance)

Another major squirt just before or at TDC to continue the flame and
increase the PSI ever more.

Maybe a third squirt to finish and clean, but am not sure nor fully
noodled how that would effect emissions, yet

It id can't be done with diesel, then am almost for sure it can be
for gasoline and also think brings back big blocks !!!!