ignition assist systems for direct injected diesel cycle, medium-duty alternative … · ·...
TRANSCRIPT
February 2000 • NREL/SR-540-27502
A.K. ChanCaterpillar, Inc.Peoria, Illinois
Ignition Assist Systems forDirect-Injected, Diesel Cycle,Medium-Duty Alternative FuelEngines
Final Report Phase I
National Renewable Energy Laboratory1617 Cole BoulevardGolden, Colorado 80401-3393NREL is a U.S. Department of Energy LaboratoryOperated by Midwest Research Institute !!!! Battelle !!!! Bechtel
Contract No. DE-AC36-99-GO10337
February 2000 • NREL/SR-540-27502
Ignition Assist Systems forDirect-Injected, Diesel Cycle,Medium-Duty Alternative FuelEngines
Final Report Phase I
A.K. ChanCaterpillar, Inc.Peoria, Illinois
NREL Technical Monitor: Keith VertinPrepared under Subcontract No. ZAS-7-16609-01
National Renewable Energy Laboratory1617 Cole BoulevardGolden, Colorado 80401-3393NREL is a U.S. Department of Energy LaboratoryOperated by Midwest Research Institute !!!! Battelle !!!! Bechtel
Contract No. DE-AC36-99-GO10337
This publication was reproduced from the best available copySubmitted by the subcontractor and received no editorial review at NREL
NOTICE
This report was prepared as an account of work sponsored by an agency of the United Statesgovernment. Neither the United States government nor any agency thereof, nor any of their employees,makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy,completeness, or usefulness of any information, apparatus, product, or process disclosed, or representsthat its use would not infringe privately owned rights. Reference herein to any specific commercialproduct, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarilyconstitute or imply its endorsement, recommendation, or favoring by the United States government or anyagency thereof. The views and opinions of authors expressed herein do not necessarily state or reflectthose of the United States government or any agency thereof.
Available electronically at http://www.doe.gov/bridge
Available for a processing fee to U.S. Department of Energyand its contractors, in paper, from:
U.S. Department of EnergyOffice of Scientific and Technical InformationP.O. Box 62Oak Ridge, TN 37831-0062phone: 865.576.8401fax: 865.576.5728email: [email protected]
Available for sale to the public, in paper, from:U.S. Department of CommerceNational Technical Information Service5285 Port Royal RoadSpringfield, VA 22161phone: 800.553.6847fax: 703.605.6900email: [email protected] ordering: http://www.ntis.gov/ordering.htm
Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste
Acknowledgement
This research was sponsored by Stephen Goguen, Program Manager in the Department ofEnergy’s Office of Heavy Vehicle Technologies. The technical monitor for this project wasKeith Vertin, Senior Engineer at the National Renewable Energy Laboratory.
4Requires extensivedevelopment
2Large
< 1Plasma energy and plumevolume
Early injection of fuel through plasmajet ignitor
Stratified ChargePlasma Ignition
5Fuel supply problems3Large(Injection plume)
2 - 3Fuel additive concentrationand autoignition temperature
Addition of ethane to natural gas toaid autoignition
Fuel Additives
3Pilot fuel consumption issues2Large(Injection plume)
1 - 2Fuel pilot cetane number andquantity
Small quantity of high cetane fluidinjected with natural gas
Micropilot Injection
5Power requirement andemissions issues
2Large(Injection plume)
2 - 3Inlet air temperature andcompression ratio
Inlet air heating and increasedcompression ratio of engine to induceautoignition
Inlet Air Heating
4Cost and component durabilityfar from production
4Small(Laser focal volume)
1 - 2Laser energy and localequivalence ratio
Gases in laser focal volume ionized byintense thermal heating
Laser Plasma
4Cost and component durabilityfar from production
4Small(Laser focal volume)
1 - 2Laser energy and local fuelconcentration
Excitation of fuel molecules in laserfocal volume by laser wavelength
Laser Excitation
5Injector and power supplyrequire development
1Large(Injection plume)
< 1Initial fuel temperatureFuel raised to ignition temperatureprior to or during injection
Fuel Preheating
4Durability requiresdevelopment
5Medium(Layer at pre-chamber wall)
2 - 3Surface Temperature and localequivalence ratio
Heat transfer to mixture from internalhot surface
Heated Pre-chamber
4Durability requiresdevelopment
2Large(Plasma plume volume)
< 1Plasma energy and plumevolume
Plasma generated and propelled intocylinder
Plasma Jet Ignitor
2Durability and electronicsunproven
3Small(Spark plug gap)
1 - 2Local equivalence ratio andspark energy
Multiple sparks with feedback controlSmartFire SparkPlug
2Durability and electronicsunproven
4Small(Spark plug gap)
1 - 2Local equivalence ratio andspark energy
Short duration high power sparkSDHP Plug
2Power supply and controlsrequire development
3Small(Spark plug gap)
1 - 2Local equivalence ratio, sparkduration and spark energy
Long duration high frequency sparkinitiated early in compression stroke
AC Spark Plug
1Durability requiresdevelopment
5Medium(Layer near glow plug surface)
2 - 3Surface temperature and localequivalence ratio
Heat transfer to mixture from externalhot surface
Glow Plug
Action(Note 1)
Production Limiting FeatureEst. COV(Note 2)
Ignition VolumeEst. Ign.Delay(ms)
Determinant of IgnitionDelay
Working PrincipleSource of IgnitionAssist
Note 1: '1' - Continue development. '2' - Initiate development. '3' - Perform concept study. '4' - Monitor outside research. '5' - Will reevaluate if encounter newdevelopment.Note 2: COV = Coefficient of Variation. Scale: 5 - high, 1 - low
Table 1: Direct Injection Natural Gas Engine Ignition Options Survey
Figure 1: Constant volume high pressure chamber
-17-
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
250
300
Bre
akdo
wn
Vol
tage
(kV
)
predicted curve & point - 1.5 mm gap predicted curve & point - 1.0 mm gap predicted curve & point - 0.5 mm gap
Predicted Breakdown Voltage vs Pressure'Uniform-Field' Electrodes
Figure 2: Predicted Breakdown Voltage vs Pressure by Paschen’s law
-19-
Figure 3: 60 Hz AC power supply
Figure 4: Electrode mounting fixture
-21-
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
Bre
akdo
wn
Vol
tage
(kV
)
data point - 1.5 mm gapdata point - 1.0 mm gapdata point - 0.5 mm gapbest fit curve - 1.5 mm gapbest fit curve - 1.0 mm gapbest fit curve - 0.5 mm gap
Breakdown Voltage vs PressureFlat-Flat Electrodes
Figure 5: Breakdown Voltage vs Pressure for Flat-Flat electrodes
-23-
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
Bre
akdo
wn
Vol
tage
(kV
)data point - 1.0 mm gapdata point - 0.5 mm gapbest fit curve - 1.0 mm gapbest fit curve - 0.5 mm gap
Breakdown Voltage vs PressureFlat-Round Electrodes
Figure 6: Breakdown Voltage vs Pressure for Flat-Round electrodes
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
Bre
akdo
wn
Vol
tage
(kV
)
data point - 0.5 mm gapbest fit curve - 0.5 mm gap
Breakdown Voltage vs PressureFlat-Point Electrodes
Figure 7: Breakdown Voltage vs Pressure for Flat-Point electrodes
-26-
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
Bre
akdo
wn
Vol
tage
(kV
)predicted curve & point - Paschen's Lawbest fit curve & predicted point - Flat-Round electrodesbest fit curve & predicted point - Flat-Flat electrodes
Breakdown Voltage vs Pressure0.5 mm Gap
Figure 8: Comparison of breakdown voltages for a 0.5 mm gap
100 200 300 400 500 600 700 800 900 1000 1100
Pressure (psig)
0
50
100
150
200
250
300
Bre
akdo
wn
Vol
tage
(kV
)
predicted curve & point - Paschen's Lawbest fit curve & predicted point - Flat-Round electrodesbest fit curve & predicted point - Flat-Flat electrodesbest fit curve & predicted point - Flat-Point electrodes
Breakdown Voltage vs Pressure1.0 mm Gap
Figure 9: Comparison of breakdown voltages for a 1.0 mm gap
-27-
Figure 10: High frequency AC power supply
-29-
DC Power Supply15 to 20 Volts
20 amps
AdjustableHigh Frequency
Generator
AdjustableSpark Duration
Control
AdjustableSpark
RepetitionRate
Control
Low Voltage Logicto High Voltage
CircuitInterface
"H" BridgeCircuitry
Ignition coilExternal singlespark control
5 VoltRegulator
1 Amp
12 VoltRegulator
1 Amp
108 Volts1 Amp
Continuous17 Ampsurge
Enable
Switch
Disable
Spark Plugin
PressureChamber
Power and Ground
Signal Line
Figure 11: Schematic diagram of the high frequency AC power supply
-30-
Figure 12: EIS (electronic ignition system)
Figure 13: SDHP (short duration high power) ignition system
-35-
0 20 40 60 80 100 120 140 160
Time (micro-seconds)
-50
-40
-30
-20
-10
0
10
Out
put V
olta
ge (k
V)
'Open Circuit' VoltageCoil made by Adrenaline Research Inc.
Figure 14: Voltage Output vs Time
Figure 15: Adrenaline plugs made by Champion
-37-
Figure 16: ‘S martFire’ ignition system
-38-
Figure 17: Spark plug after bench testing with the Adrenaline System (0.46 mm gap)
Figure 18: Spark plug after bench testing with the Adrenaline System (0.51 mm gap)
-40-
Figure 19: Spark plug after bench testing with the Adrenaline System (1.02 mm gap)
Figure 20: Spark plug after bench testing with the Adrenaline System (1.27 mm gap)
-41-
Figure 21: Ceramic disk sandwiched in the portable oil tester
Figure 22: Ceramic disk sandwiched in the portable oil tester submerged the oil bath
-45-
Figure 23: Disks showing original coatings
Figure 24: Disks showing modified coatings
-46-
3.5 4 4.5 5 5.5 6 6.5
Thickness (mm)
20
30
40
50
60
70
80
90
100
110
Bre
akdo
wn
Vol
tage
(kV
)
data point -Diala oildata point - AD-94data point - TiO2best fit curve - Diala oil
Breakdown Voltage vs Thickness
Figure 25: Breakdown Voltage vs Insulator Thickness
-47-
Figure 26: Glow plug shield
-52-
Figure 27: Prototype ceramic insulator body
Figure 28: Prototype spark plug assembly
-54-
Figure 29: Prototype ceramic insulator body for surface-discharge plug
Figure 30: Prototype surface-discharge spark plug assembly
-55-
Figure 31: Central electrode for the air-gap spark plug
Figure 32: Central electrode for the surface-discharge spark plug
-56-
Figure 33: Modified 3126 DING cylinder head
Figure 34: Cutout view showing the glow plug and the spark plug hole
-57-
Figure 35: Sectional view of the glow plug and the air-gap spark plug holes
Figure 36: Sectional view showing the ‘gas retainer/ground electrode’
-58-
Figure 37: Air-gap plug in the cylinder head
Figure 38: Sectional view of the air-gap plug in the cylinder head
-59-
Figure 39: Spark gap between the central electrode and the ground electrode
Figure 40: Sectional view of the glow plug and the surface-discharge spark plug holes
-61-
Figure 41: Surface-discharge plug in the cylinder head
Figure 42: Sectional view of the surface-discharge plug in the cylinder head
-62-
Figure 43: Surface spark gap between the central electrode and the ground electrode
Figure 44: Mounting clamp
-63-
Figure 45: Plug in cylinder head with mounting clamp
Figure 46: Side view of plug in cylinder head with mounting clamp
-64-
REPORT DOCUMENTATION PAGE Form ApprovedOMB NO. 0704-0188
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing datasources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or anyother aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations andReports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188),Washington, DC 20503.
1. AGENCY USE ONLY (Leave blank) 2. REPORT DATEFebruary 2000
3. REPORT TYPE AND DATES COVEREDSubcontract Report
4. TITLE AND SUBTITLEIgnition Assist Systems for Direct Injected Diesel Cycle, Medium-Duty Alternative Fuel Engines
6. AUTHOR(S)Anthony K. Chan
5. FUNDING NUMBERSC: ZAS-7-16609-01TA: FU903110
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Caterpillar, Inc.Peoria, Illinois
8. PERFORMING ORGANIZATIONREPORT NUMBER
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)National Renewable Energy Laboratory1617 Cole Blvd.Golden, CO 80401-3393
10. SPONSORING/MONITORINGAGENCY REPORT NUMBER
NREL/SR-540-27502
11. SUPPLEMENTARY NOTES
NREL Technical Monitor: Keith Vertin
12a. DISTRIBUTION/AVAILABILITY STATEMENTNational Technical Information ServiceU.S. Department of Commerce5285 Port Royal RoadSpringfield, VA 22161
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words)This report is a summary of the results of Phase 1 of this contract. The objective was to evaluate the potential of assist technologies fordirect-injected alternative fuel engines vs. glow plug ignition assist. The goal was to demonstrate the feasibility of an ignition system lifeof 10,000 hours and a system cost of less than 50% of the glow plug system, while meeting or exceeding the engine thermal efficiencyobtained with the glow plug system. There were three tasks in Phase 1. Under Task 1, a comprehensive review of feasible ignitionoptions for DING engines was completed. The most promising options are: 1) AC and the “SmartFire” spark, which are both long-duration, low-power (LDLP) spark systems; 2) the short-duration, high-power (SDHP) spark system; 3) the micropilot injection ignition;and 4) the stratified charge plasma ignition. Efforts concentrated on investigating the AC spark, “SmartFire” spark, and short-duration/high-power spark systems. Using our proprietary pricing information, we predicted that the commercial costs for the AC spark,the short-duration/high-power spark and “SmartFire” spark systems will be comparable (if not less) to the glow plug system. Task 2involved designing and performing bench tests to determine the criteria for the ignition system and the prototype spark plug for Task 3.The two most important design criteria are the high voltage output requirement of the ignition system and the minimum electricalinsulation requirement for the spark plug. Under Task 3, all the necessary hardware for the one-cylinder engine test was designed. Thehardware includes modified 3126 cylinder heads, specially designed prototype spark plugs, ignition system electronics, and parts for thesystem installation. Two 3126 cylinder heads and the “SmartFire” ignition system were procured, and testing will begin in Phase 2 of thissubcontract.
15. NUMBER OF PAGES 14. SUBJECT TERMS
Direct injection; alternative fuel engines; ignition assist systems; diesel cycle; medium-dutyengines 16. PRICE CODE
17. SECURITY CLASSIFICATIONOF REPORTunclassified
18. SECURITY CLASSIFICATIONOF THIS PAGEunclassified
19. SECURITY CLASSIFICATIONOF ABSTRACTunclassified
20. LIMITATION OF ABSTRACT
UL
NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)Prescribed by ANSI Std. Z39-18
298-102