HOMOGENEOUS CHARGE CATALYTIC IGNITION OF …€¦ · Research and Special Programs ... Most...

HOMOGENEOUS CHARGE CATALYTIC IGNITION OF ETHANOL-WATER/AIR MIXTURES IN A

RECIPROCATING ENGINE

Final Report

KLK752A

Compression Ratio and Catalyst Aging Effects on Aqueous Ethanol

N09-04

National Institute for Advanced Transportation Technology

University of Idaho

Dan Cordon, Dr. Steven Beyerlein

April 2009

DISCLAIMER

The contents of this report reflect the views of the authors,

who are responsible for the facts and the accuracy of the

information presented herein. This document is disseminated

under the sponsorship of the Department of Transportation,

University Transportation Centers Program, in the interest of

information exchange. The U.S. Government assumes no

liability for the contents or use thereof.

1. Report No. 2. Government Accession

No.

3. Recipient’s Catalog No.

4. Title and Subtitle

Compression Ratio and Catalyst Aging Effects on Aqueous Ethanol: Homogeneous Charge Catalytic Ignition of Ethanol-Water/Air Mixtures in

a Reciprocating Engine

5. Report Date

April 2009

6. Performing Organization

Code

KLK752A

7. Author(s)

Cordon, Dan; Beyerlein, Dr. Steven

8. Performing Organization

Report No.

N09-04

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

National Institute for Advanced Transportation Technology

University of Idaho

PO Box 440901; 115 Engineering Physics Building

Moscow, ID 838440901

11. Contract or Grant No.

DTRT07-G-0056

12. Sponsoring Agency Name and Address

US Department of Transportation

Research and Special Programs Administration

400 7th Street SW

Washington, DC 20509-0001

13. Type of Report and Period

Covered

Final Report: August 2007

– December 2008

14. Sponsoring Agency Code

USDOT/RSPA/DIR-1

15. Supplementary Notes:

16. Abstract

Lean ethanol-water/air mixtures have potential for reducing NOx and CO emissions in internal combustion

engines, with little well-to-wheels CO2 emissions. Conventional ignition systems have been unsuccessful at

igniting such mixtures. An alternative catalytic ignition source is being developed to aid in the combustion of

aqueous ethanol. The operating principle is homogeneous charge compression ignition inside a catalytic pre-

chamber, which causes torch ignition and flame propagation in the combustion chamber. Ignition timing can be

adjusted by changing the length of the catalytic core element, the length of the pre-chamber, the diameter of the

pre-chamber, and the electrical power supplied to the catalytic core element. To study engine operation, a 1.0L 3-

cylinder Yanmar diesel engine was converted for ethanol-water use, and compared with an unmodified engine.

Comparing the converted Yanmar to the stock engine shows an increase in torque and power, with improvements

in CO and NOx emissions. Hydrocarbon emissions from the converted engine increased significantly, but are

largely due to piston geometry not well suited for homogeneous charge combustion. No exhaust after treatment

was performed on either engine configuration. Applying this technology in an engine with a combustion chamber

and piston design suited for homogeneous mixtures has the potential to lower emissions to current standards, with

a simple reduction catalytic converter.

17. Key Words

Pollutant control, fuel systems, engine

testing, renewable fuels

18. Distribution Statement

Unrestricted; Document is available to the public

through the National Technical Information Service;

Springfield, VT.

19. Security Classif. (of

this report)

Unclassified

20. Security Classif. (of

this page)

Unclassified

21. No. of Pages

19

22. Price

…

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

Homogeneous Charge Catalytic Ignition of Ethanol-Water/Air i

Mixtures in a Reciprocating Engine

Table of Contents

Introduction ............................................................................................................................... 1

Catalytic Igniters ....................................................................................................................... 2

Engine Conversions ................................................................................................................... 4

Experimental Apparatus ............................................................................................................ 5

Engine Performance .................................................................................................................. 7

Modal Comparison .................................................................................................................. 11

Conclusion ............................................................................................................................... 16

References ............................................................................................................................... 17

Appendix ................................................................................................................................. 18

Figures

Figure 1 – Exploded view of catalytic igniter. .......................................................................... 2

Figure 2 – Flame pattern exiting pre-chamber nozzle. .............................................................. 3

Figure 3 – Experimental apparatus for engine testing. .............................................................. 6

Figure 4 – Full load BMEP for diesel and aquanol. .................................................................. 7

Figure 5 – Full load power for diesel and aquanol. ................................................................... 8

Figure 6 – Equivalence ratio for full load curves. ..................................................................... 9

Figure 7 – Performance map for diesel engine. ....................................................................... 10

Figure 8 – Performance map for aquanol engine. ................................................................... 10

Figure 9 – Mode points for comparing engines. ..................................................................... 11

Figure 10 – Efficiency in KJ/kWh. ......................................................................................... 12

Figure 11 – Equivalence ratio at each mode point. ................................................................. 13

Figure 12 – Brake specific carbon monoxide. ......................................................................... 13

Figure 13 – Brake specific hydrocarbons. ............................................................................... 14

Figure 14 – Brake specific carbon dioxide. ............................................................................. 15

Figure 15 – Brake specific oxides of nitrogen. ....................................................................... 15

Homogeneous Charge Catalytic Ignition of Ethanol-Water/Air ii


Tables

Table 1 – Original Yanmar Engine Specifications [12]. ........................................................... 5

Homogeneous Charge Catalytic Ignition of Ethanol-Water/Air 1


INTRODUCTION

Lean burn piston engines are an avenue for reducing fuel consumption and environmental impact.

The difficulty in burning lean air/fuel mixtures spawned the development of the catalytic igniter

(1). Most homogeneous charge lean burn engines suffer from reduced power output per

displacement and incompatibility with oxidation/reduction catalysts (2). The catalytic igniter was

developed to help overcome these issues. Previous engine conversions have shown an increase in

net thermal efficiency and power output and have been able to operate under lean conditions with

reduced emissions.

The University of Idaho has been working with Automotive Resources Inc. for the past ten years

to study catalytic igniters in engines fueled by ethanol-water blends. Initially, lean ethanol

mixtures were studied, but resulted in high nitrogen oxide (NOx) emissions. Adding water to the

fuel lowered combustion temperatures and resulted in a large reduction of NOx emissions.

Mixtures of up to 50 percent ethanol and 50 percent water (by volume) have been used in test

engines. Because no noticeable benefits were noticed beyond 30 percent water, a 70/30 blend of

ethanol/water (by volume) was used in this study. This mixture is sometimes called “aquanol.”

Because ethanol readily adsorbs water, no special emulsions or processes are required to mix this

fuel.

Combusting aqueous fuel in a piston engine requires a larger ignition source than necessary for

gasoline. High-energy spark ignition systems are capable of initiating combustion, but the high

water content in the cylinder tends to quench the flame front. Past attempts at compression

ignition of aqueous fuel has been unsuccessful due to difficulties in controlling ignition timing.

Modern homogeneous charge compression ignition (HCCI) control systems may open this

opportunity in the future. Using a catalyst provides a consistent and controllable ignition source

with sufficient energy to sustain combustion of the in-cylinder mixture.

The use of water in combustion – either mixed with the fuel or injected separately – is not new,

and has been published in many papers. Cold-starting with greater than 20 percent water has not

been found in the literature. Once at operating temperatures, many engines using more than 20

percent water require significant energy for an air pre-heater in order to sustain combustion (5, 6,



7, and 8). Catalytic ignition has been successful with cold starting engines with as much as 50

percent water in the fuel, and the electrical energy used to heat the catalyst is 0-20W per cylinder.

CATALYTIC IGNITERS

The catalytic igniter is a self-contained ignition system that can be retrofitted to Spark Ignition

(SI) and most Compression Ignition (CI) engines. For SI engines, the catalytic igniter is located in

the spark plug hole. Conversions for CI engines must be on direct injection engines, and the

catalytic igniter is located in place of the injector. An illustration of a typical catalytic igniter is

shown in Figure 1. The igniter core is a hollow ceramic rod with a heating element embedded in

the bottom end. A coating of noble metal catalyst paste is painted over the heater element. The top

end of the tube is sealed with an electrical feed through for the heating element. This assembly is

screwed in to a brass pre-chamber. The lower end of this pre-chamber is mounted to the cylinder

head where the tip is exposed to the combustion chamber. Holes in the end of the pre-chamber

allow fresh mixture to enter and a torch-like ignition source to exit.

Figure 1 – Exploded view of catalytic igniter.

Ignition begins during the compression stroke, as soon as fresh mixture comes in contact with the

hot catalytic surface. Reduced activation energy associated with heterogeneous catalysts means

that this occurs far below the normal gas-phase ignition temperature (9). Combustion products

and intermediate species accumulate in the top of the pre-chamber above the heated catalyst.



After sufficient pressure and temperature from energy release and compression occur, multi-point

homogeneous ignition inside the pre-chamber results (9, 10). The combusting mixture is released

out the bottom of the pre-chamber through nozzles that direct the flame around the main

combustion chamber. This flame becomes the source of ignition for the main combustion

chamber, which burns in a typical flame propagation method. It is believed that the high energy

and large volume of this main chamber ignition source are largely responsible for stable operation

on lean ethanol-water mixtures.

In-cylinder imaging has not been captured. To approximate the flame pattern exiting the catalytic

igniter, a propane-air mixture was pumped through the top of the pre-chamber and past the hot

catalyst surface. The resulting flame pattern is shown in Figure 2. It is believed that this is similar

to what occurs in operation, but this has not yet been confirmed.

Figure 2 – Flame pattern exiting pre-chamber nozzle.

Controlling ignition timing is a critical problem with any homogeneous charge compression

ignition engine. Both Yanmar conversion engines operate without a throttle plate, so only the

amount of fuel injected determines the engine power output. Because of this, the air/fuel ratio

varies greatly over the operating range of the engine. The original diesel engine is direct injection,

and fuel burns in a diffusion method. The aquanol conversion is a premixed air/fuel mixture – fuel

is injected in the intake manifold – and operates via flame propagation.

A mathematical model was created to explore parameters that effect ignition timing with the

catalytic igniter (11). In the case of an unthrottled engine, adjustment of ignition timing



characteristics was best accomplished by changing the length of the ceramic core, and therefore

the position of the catalyst in the pre-chamber. Shortening the rod would move the heated catalyst

section higher in the pre-chamber, causing there to be a greater delay in the fresh mixture coming

in contact with the catalyst. This resulted in a retardation of the ignition timing. Conversely,

longer rods resulted in advancing ignition timing. The relationship between igniter core length

and ignition is not completely linear. However, in the ranges used, a core length change of 1.0mm

resulted in a ~5° change in ignition timing.

Dynamic change of the catalyst location was not possible. The final decision of igniter core length

was done by observing in-cylinder pressure traces and changing out the cores for different

lengths. Testing started with a short length so the ignition timing would be retarded and relatively

safe. The engine was run through a full load RPM sweep, and if there were no regions where

ignition was too advanced, a longer core would be installed and the engine tested again. This was

repeated until detonation was observed. The longest (most advanced timing) that did not

experience detonation was selected for this study. Ignition timing was not optimal for all

operating points, and use of a programmable heating circuit has potential to improve engine

performance and emissions.

ENGINE CONVERSIONS

Two Yanmar diesel engines were used in this work. Specifications are given in Table 1. Both

were recently rebuilt and brake-in was performed as per manufacturer recommendations. One

engine was left in original configuration to be used as a baseline comparison for this work. All

previous aquanol conversions were done on SI engines. In these conversions, the original throttle

was maintained, and engines were tuned to maintain a near-constant air/fuel ratio over the entire

operating range. In an attempt to study high compression ratios and lean combustion, the Yanmar

conversion was not fitted with a throttle. Engine output is controlled only by the amount of fuel

injected in to the intake manifold. Because the in-cylinder volume remains relatively constant,

changes in fuel injection quantity result in a wide range of homogeneous air/fuel equivalence

ratios.



Table 1 – Original Yanmar Engine Specifications [12]

Model 3TN75E

(S) Cylinders 3

Bore 75 mm

Stroke 75 mm

Displacement 0.994 L

Compression

Ratio

17.61:1

1-hr Rated Power 16.0 kW

1-hr Rated Speed 3000

RPM

Conversion of the Yanmar engine was relatively simple. A multi-port fuel injection system was

fitted to the original intake manifold, with automotive-style fuel injectors. The diesel pump and

injectors were removed, and catalytic igniters were placed in the direct fuel injector ports. Both

engines were equipped with alternators, and any electrical load used by the engine (air pre-heaters

and catalytic igniters) were powered by these alternators. Prior to each engine test session, the

engines were allowed to run for several minutes until they reached operating temperatures and

recharged the starting battery. The aquanol conversion also had the cylinder head machined for a

combustion pressure sensor to be fitted flush with the cylinder head. This was not required for the

conversion, but was used for adjusting ignition timing and measuring combustion trends in the

engine. In previous conversions, the pre-chamber volume was between 5-7 percent of the original

combustion chamber volume. For the aquanol conversion, each pre-chamber volume was 1.4 cm3

– 7.1 percent of the original TDC volume. This resulted in lowering the compression ratio to

~16.5:1 (13).

EXPERIMENTAL APPARATUS

Figure 3 shows the experimental apparatus used for data collection. Because the combustion

pressure sensors were flush mounted to the combustion chamber, full Envar bodies were required.

These were obtained from PCB, model number 112M275. The capacitive signal from the pressure

sensors was sent to a charge converter (PCB model 422M96), then to either a 100 MHz

oscilloscope or a Redline DSP combustion analyzer depending on the test. A 1000

pulse/revolution encoder was fitted to the front of the crankshaft, and a second channel with a 1

pulse/revolution signal was used to reference TDC of cylinder 1. A Land-and-Sea water brake

dynamometer (9” size) with an electronic controlled water valve was used to provide a steady-



state load for engine testing. Calibration of the dynamometer was performed before each run, and

confirmed after each run to detect signs of torque drift. Fuel flow was recorded by a Max

Machinery model 710 fuel conditioning cart with temperature corrected calibrations for both

diesel and 70/30 aquanol fuel.

Figure 3 – Experimental apparatus for engine testing.

Not shown on Figure 3 are the bungs for measuring exhaust gas temperature (EGT) and

emissions. The EGT bung was located in the exhaust manifold collector, 150-250 mm

downstream of the exhaust valve depending on the cylinder. Because of this, EGT readings are

much lower than observed with closer temperature probes. In this study, the EGTs are only used

to compare the engines to one another. The emissions collection bung was located 24” upstream

of the exhaust exit to minimize any effects from ambient air getting in to the exhaust system

between exhaust pulses. Emissions were detected by an Emissions System Inc. 5-gas analyzer,

model 5001-5. This model uses a Peltier cooler to remove water from the incoming exhaust

sample line. A NDIR sensor is used to measure CO, CO2, and HC (hexane equivalent)

concentrations. Electrochemical sensors are used to measure NOx and O2 concentrations.



ENGINE PERFORMANCE

BMEP and SAE corrected shaft power are shown for both the stock diesel and aquanol

conversion in Figures 4 and 5. The Yanmar spec for peak engine speed is 3000 RPM. In original

configuration, the slow burn rate of fuel keeps the engine from running beyond this speed.

However, the homogeneous mixture of the converted engine burns quite rapidly in comparison.

The converted engine was capable of much higher engine speeds, but because this was outside the

max speed rating, the aquanol engine was tuned to cut fuel for any speed over 3100 RPM. If the

rotating assembly was safe to run beyond this speed, power output from the aquanol engine may

have been higher still.

Figure 4 – Full load Brake Mean Effective Pressure (BMEP)

for diesel and aquanol.

Full Load BMEP

600

650

700

750

800

850

900

950

1500 2000 2500 3000

Engine Speed [RPM]

BM

EP

[k

Pa

]

Aquanol

Diesel



Figure 5 – Full load power for diesel and aquanol.

The aquanol engine had higher full load Brake Mean Effective Pressure (BMEP) and power

curves than the diesel engine. The equivalence ratio for the full load data is shown in Figure 6. It

was calculated using an equation recommended by the manufacturer of the 5-gas analyzer.

Several runs were made with the aquanol engine operating under higher equivalence ratios than

displayed in these figures. Under richer conditions the engine produced even higher torque and

power levels, but the emissions of CO increased by as much as 200 percent. Thus the engine was

de-tuned to produce reasonable emissions at the cost of peak performance.

Full Load Power

8

10

12

14

16

18

20

22

24

1500 2000 2500 3000

Engine Speed [RPM]

Po

wer

[kW

]

Aquanol

Diesel



Figure 6 – Equivalence ratio for full load curves.

The lower heating value for a 70/30 aquanol blend is calculated at 17.4 MJ/kg – 42 percent lower than

diesel fuel at 41.4 MJ/kg. Because of this, comparing Brake Specific Fuel Consumption (BSFC) numbers

directly would not tell the full story. Instead, net thermal efficiency was used to compare the two engines.

Based on evenly captured data over the full range of operating conditions, performance maps with lines

of constant net thermal efficiency were created. Figure 7 shows the performance map for the diesel

engine, and Figure 8 shows the aquanol engine.

Equivalence Ratio at Full Load

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1500 2000 2500 3000

Engine Speed [RPM]

Eq

uiv

ale

nce R

ati

o

Aquanol

Diesel



Figure 7 – Performance map for diesel engine.

Figure 8 – Performance map for aquanol engine.

The diesel engine has a wide range of operation where there is high efficiency. From 2000-3000

RPM and 40-80 percent load, the engine is over 30 percent efficient. This covers nearly ¾ of the

operating range of the engine. The aquanol conversion is quite efficient at high loads (above 80

23.9

23.9

25.5

27.1

27.1

28.6

28.6

28.628.6

30.2

30.2

30.2

31.833.4

33.4

34.9

34.9

Speed RPM

To

rqu

e N

*m

Diesel Thermal Efficiency

1500 2000 2500 3000

20

30

40

50

60

10.5

10.513.2

15.9

18.621.3

21.3

24

26.7

29.4

29.4

32.1 32.132.1

34.8

34.8

34.8

Speed RPM

To

rqu

e N

*m

Aquanol Thermal Efficiency

1500 2000 2500 3000

20

30

40

50

60

70



percent of peak load) but efficiency continually falls with reduced load. At lower loads there is a

very lean homogeneous mixture in the cylinder. Based on emissions collected at these points,

combustion efficiency is extremely poor. When operating below 20 N*m and under 2500 RPM,

the aquanol engine is at an equivalence ratio slightly below 0.3. However, at high load across a

wide RPM range the aquanol conversion has a comparable thermal efficiency to the diesel engine.

MODAL COMPARISON

Contour plots of Brake Specific Emissions were cluttered, and some of the emissions are on

different orders of magnitude between the two engines. Instead, nine mode points based on

BMEP and engine speed were selected for comparison as shown in Figure 9. The mode points are

labeled 1-9. Mode points 1-6 correlate to the diesel engine at peak load. Aquanol data was

selected that most closely matched to the diesel engine mode points. Load point 7 represents low

load and medium speed. Load point 8 represents low load and high speed. Load point 9 is at a

medium load and speed. Brake specific emissions were calculated using the EPA 40 CFR Part 91

Section 419c. See Appendix A for a sample calculation.

Figure 9 – Mode points for comparing engines.

Efficiency maps for the whole operating range were shown in Figures 7 and 8. Figure 10 shows

efficiency at each mode point given in units of kJ/kWh. This shows the rate of fuel energy used

(mass flow * heating value) divided by the power output of the engine. Lower numbers represent

Mode Points and Net Thermal Efficiency

0

100

200

300

400

500

600

700

800

900

1000

1500 2000 2500 3000

Engine Speed [RPM]

BM

EP

[k

Pa

]

Diesel Mode Points

Aquanol Mode Points

12 3 4 5

6

7 8

9



higher efficiency than larger numbers. Shown in Figure 11 is the equivalence ratio for each mode

point. The diesel engine operates leaner than the aquanol engine at every mode point. Of interest

is how the two engines compare when operating under the same speed and equivalence ratio.

Mode point three of the diesel data and point seven of the aquanol data provide this comparison.

The equivalence ratio of the aquanol engine at point seven is similar to the equivalence ratio of

diesel at point three, and they are both at the same engine speed (2250 RPM). Under these

conditions the aquanol engine makes less power than the diesel engine and is also much less

efficient. The combustion efficiency of the diesel engine is quite good at this point, but the lean

homogeneous mixture does not burn very completely. This is also evident in the hydrocarbon

emissions.

Figure 10 – Efficiency in KJ/kWh.

Energy Usage Comparison

0

5000

10000

15000

20000

25000

30000

35000

1 2 3 4 5 6 7 8 9

Mode Points

Eff

icie

ncy [

kJ/k

W*h

r]

Diesel Aquanol



Figure 11 – Equivalence ratio at each mode point.

Carbon monoxide emissions are given in Figure 12. At the higher load points and equivalence

ratios (points 1-6) the aquanol engine produced fewer CO emissions compared to the diesel

engine. However, at the highly lean conditions of low load (points 7 and 8), the aquanol engine

produced greater amounts of CO.

Figure 12 – Brake specific carbon monoxide.

Equivalence Ratio

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1 2 3 4 5 6 7 8 9

Mode Points

Ph

i

Diesel

Aquanol

Brake Specific CO Comparison

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9

Mode Point

BS

CO

[g

m/k

W-h

r]

Diesel

Aquanol



Brake specific hydrocarbon emissions are shown in Figure 13. At all operating conditions, the

aquanol conversion was off the charts compared to the diesel engine. The data points for the

diesel do not even register on the figure, but peaked out at 1.04 gm/kW-hr at mode point 7. Mode

points 1-6 were all under 0.6 gm/kW-hr. A diffusion flame in a lean environment should have low

HC emissions. The aquanol conversion had its lowest BSHC emissions at full load where the

mixture was near stoichiometric. As the mixture got leaner, less and less of the mixture was

completely burned. The two lowest load modes (points 7 and 8) had very poor BSHC emissions.

A simple reduction catalytic converter may help clean this up, but because of the significant

amount of chemical energy to be released a thermal reactor may be a better choice for this

application.

Figure 13 – Brake specific hydrocarbons.

Brake specific CO2 was also calculated for both engines and shown in Figure 14. A well-to-

wheels analysis would give the bio mass fuel a clear advantage as the net CO2 release is minimal.

At moderate loads, the tailpipe BSCO2 emissions are similar between the two engines. At low

loads, the aquanol engine releases nearly 300 percent more CO2 out the tailpipe than the diesel.

Brake Specific HC Comparison

0

50

100

150

200

250

1 2 3 4 5 6 7 8 9

Mode Point

BS

HC

[g

m/k

W-h

r]

Diesel

Aquanol



Figure 14 – Brake specific carbon dioxide.

Brake specific NOx emissions are shown in Figure 15. As expected, NOx from the diesel engine is

much greater than the aquanol engine. The water in the ethanol fuel was used as a means of

reducing EGTs and therefore NOx emissions. It was expected that the EGTs of the aquanol engine

would be lower than the diesel. This was not the case as the diesel EGTs ranged between 63 –

137°C, while the aquanol EGTs ranged between 170 – 255°C. The flame temperature of aqueous

ethanol is much lower than gasoline or diesel, and homogeneous charge combustion typically

have reduction in NOx emissions.

Figure 15 – Brake specific oxides of nitrogen.

Brake Specific CO2 Comparison

0

500

1000

1500

2000

2500

3000

3500

1 2 3 4 5 6 7 8 9

Mode Point

BS

CO

2 [

gm

/kW

-hr]

Diesel

Aquanol

Brake Specific NOx Comparison

0

1

2

3

4

5

6

7

8

1 2 3 4 5 6 7 8 9

Mode Point

BS

NO

x [

gm

/kW

-hr]

Diesel

Aquanol



CONCLUSION

The use of catalytic igniters allowed engine operation of homogeneous mixtures under very lean

conditions. The larger ignition source also made it possible to ignite an aqueous ethanol mixture

that was not possible with the original spark ignition system. The initial goal of aqueous ethanol

research was lean combustion without high NOx emissions. This has been realized in this work.

Slight increases in peak thermal efficiency were observed with the converted engine, and a

significant increase in engine torque and power output was also achieved.

Low load operation of the aquanol engine was possible at the lean limits at equivalence ratios of

0.3, but efficiency and emissions suffered greatly at low loads. Hydrocarbon cleanup is a logical

next step for this application so that emissions could be dropped down to gasoline engine

equivalents. Future work should be conducted with high compression ratios, and with a

combustion chamber geometry better suited for homogeneous charge applications. This may help

reduce some of the hydrocarbon emissions prior to exhaust after-treatment. A high-speed engine

should also be used to find the resonance time requirements for aqueous ethanol.



REFERENCES

1. Cherry, M., Catalytic-Compression Timed Ignition, US Patent 5 109 817, December 18,

1990.

2. Cherry, M., Morrisset, R., and Beck, N., “Extending Lean Limit with Mass-Timed

Compression Ignition Using a Plasma Torch,” Society of Automotive Engineers Paper

#921556, 1992.

3. Gottschalk, Mark A., “Catalytic Ignition Replaces Spark Plugs,” Design News, May 22,

1995.

4. Dale, J. and Oppenheim, A., “A Rationale for Advances in Technology of IC Engines,”

Society of Automotive Engineers Paper #820047, 1982.

5. Browning, L.H., and Pefley, R.K., “Kinetic Wall Quenching of Methanol Flames with

Applications to Spark Ignition Engines,” Society of Automotive Engineers Paper 790676,

1979.

6. Pischinger, F., and Kramer, K., “The Influence of Engine Parameters on the Aldehyde

Emissions of a Methanol Operated Four-Stroke Otto Cycle Engine,” Third International

Symposium on Alcohol Fuel Technology, Asilomar, CA, May 28-31, 1979.

7. Lee, W., and Geffers, W., “Engine Performance and Exhaust Emissions Characteristics of

Spark Ignition Engines Burning Methanol and Methanol Mixtures,” A.I.Ch.E. Symposium

Series #165, Vol. 73, 1977.

8. Christensen, M., and Johnasson, B., “Homogeneous Charge Compression Ignition with

Water Injection,” Society of Automotive Engineers Paper #1999-01-0182, 1999.

9. Cho, P. and Law, C., “Catalytic Ignition of Fuel/Oxygen/Nitrogen Mixtures over

Platinum,” Combustion and Flame, Vol. 66, pp. 159-170, 1986.

10. Pfefferle, L., “Catalysis in Combustion, Catalysis Reviews,” Science and Engineering

Vol. 29, pp. 219-267, 1987.

11. Cordon, D., Clarke, E., “Catalytic Igniter to Support Combustion of Ethanol- Water/Air

Mixtures in Internal Combustion Engines,” Society of Automotive Engineers Paper #

2002-01-2863, 2002.

12. Yanmar Diesel Engine Co, “Service Manual for 3TN75E Engine,” 1986

13. Clarke, E., “Characterization of Aqueous Ethanol Homogeneous Charge Catalytic

Compression Ignition,” Master’s Thesis, University of Idaho, 2001.

APPENDIX

EXAMPLE CALCULATION USING FUEL FLOW TO FIND MASS EMISSIONS

(Inputs for fuel composition are in blue. Inputs for each mode point are in yellow)

Units and Constants

Molecular Weights

Humidity Correction for NOx

Fuel Composition

Measured Engine Data

Measured Emissions Data

<--- corrected for Hexane readout

Calculated Data

Percent H2 present in exhaust (calculated)

Correction factor to correct measurements on a dry basis to a wet basis

rev 2 rad ppmMethane 1 ppmNOx 1 ppmC1 1

MCO 28.01gm

molMCO2 44.01

gm

molMNO2 46.01

gm

mol

Hspecific 3.0343gm

kgKH

1

1 0.0329 Hspecific 10.71KH 0.74

HCratio 1.75 MWfuel 12.01 1.008HCratiogm

molMWfuel 13.774

gm

mol

RPMmeasured 1750rev

minTorquemeasured 45.3925ft lbf Gfuel 7.6235

lb

hr

CO2dry 3.375% COdry .705% O2dry 15.7025%

NOxdry 371.5ppmNOx HCdry 22.256 ppmMethane

Powermeasured Torquemeasured RPMmeasured Powermeasured 11.279kW

H2dry

0.5 HCratio COdry COdry CO2dry

COdry 3 CO2dry

H2dry 0.232%

Kfactor1

1 .005 COdry CO2dry HCratio 0.01 H2dry 100 Kfactor 0.968

% Carbon

Calculated Mass Emissions

Comparing carbon flow in and carbon flow out

HCwet HCdry Kfactor HCwet 129.188ppmC1

COwet COdry Kfactor COwet 0.682%

CO2wet CO2dry Kfactor CO2wet 3.266%

NOxwet NOxdry Kfactor NOxwet 359.501ppmNOx

O2wet O2dry Kfactor O2wet 15.195%

TC COwet CO2wet

HCwet

106

100 TC 3.961

HCGfuel

T C

100

HCwet

106

HC 11.278gm

hr

COMCO

MWfuel

Gfuel

T C

100

COwet CO 1.211 103 gm

hr

CO2MCO2

MWfuel

Gfuel

T C

100

CO2wet CO2 9.11 103 gm

hr

NOxMNO2

MWfuel

Gfuel

T C

100

NOxwet

106

KH NOx 77.523gm

hr

mdot_carbon_HCHC

12.01 1.008( )gm

mol

12.01gm

molmdot_carbon_HC 10.405

gm

hr

mdot_carbon_COCO

MCO

12.01gm

molmdot_carbon_CO 519.294

gm

hr

mdot_carbon_CO2CO2

MCO2

12.01gm

molmdot_carbon_CO2 2.486 10

3 gm

hr

mdot_carbon_exh mdot_carbon_HC mdot_carbon_CO mdot_carbon_CO2

mdot_carbon_exh 3.016 103 gm

hr

mdot_carbon_fuel

Gfuel

MWfuel

12.01gm

molmdot_carbon_fuel 3.015 10

3 gm

hr

HOMOGENEOUS CHARGE CATALYTIC IGNITION OF …€¦ · Research and Special Programs ... Most...

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