Troels Dyhr Pedersen.indd - Solid Mechanics

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RPM with EGR, the combustion appears to be incomplete before EGR is applied. Apart from these two cases, all EGR experiments resulted in low CO levels. Using methanol at 1800 RPM seemed to cause high levels of CO regardless of engine load. The reason for this effect is unknown. The DOC effectively converts CO when the exhaust gas temperature is above 200° C. Since the DOC will usually be hotter than this, the emission of CO is believed to be reduced permanently and is thus of minor importance to the impact on air quality. CONCLUSION It has been demonstrated that a diesel engine with a compression ratio of 14.5 and a DI common rail system is suitable for dual fuel HCCI combustion. DME was injected directly through the common rail injectors and the methanol was port injected. The effect of high quantities of EGR was also demonstrated. Combustion timing control was first demonstrated with methanol. The best result was achieved when the equivalence ratio of methanol reached 0.120 at 1000 RPM and 0.076 at 1800 RPM. These quantities ensured complete combustion about 5 CAD ATDC at the respective engine speeds. Increasing the quantity further caused partial combustion and misfire at both engine speeds. A BMEP of 440 kPa was achieved at 1000 RPM and 380 kPa was reached at 1800 RPM with the optimum quantity of methanol. The corresponding brake efficiencies were 0.35 and 0.31 respectively, which is close to the performance of the original engine. Methanol proved to reduce engine knock to a very low level despite the increased equivalence ratio. It may therefore be used to increase the engine power by enabling higher equivalence ratios. A disadvantage of the port injection was that a large quantity of the injected methanol was diluted into the lubrication oil. This problem could possibly be avoided by mixing the methanol with the DME at a fixed ratio and injecting the mixture as a whole through the common rail injectors. EGR was also used to retard combustion timing for a fixed quantity of DME. For EGR percentages up to 65, the delay in CAD was proportional to the EGR percentage. At an EGR percentage of 70 % the rate of reaction was reduced and the heat release appeared around 2-3 CAD BTDC. BMEP increased with increasing amounts of EGR due decreased heat losses and less compression work. The highest BMEP obtained was around 260 kPa at both 1000 and 1800 RPM. Engine knock was virtually eliminated when the EGR level increased the equivalence ratio close to 1, as the rate of reaction was lowered. Combustion control of DME HCCI through simultaneous use of methanol and EGR may possibly enable the use of even higher compression ratios than 14.5. This could allow for standard diesel engines to utilize the HCCI combustion process in part load situations. In general, NOx emissions were in the 0-30 ppm range. At the operating points with the best thermal efficiencies, the calculated specific emissions of NOx were close to or less 0.1 g/kWh. Page 19 of 22
REFERENCES 1. Mingfa Yao: An Investigation on the Effects of Fuel Chemistry and Engine Operating Conditions on HCCI Combustion. SAE 2008-01-1660. 2008 2. Zunqing Zheng, Mingfa Yao, Zheng Chen, Bo Zhang: Experimental Study on HCCI Combustion of Dimethyl Ether (DME)/Methanol Dual Fuel. SAE paper 2004-01-2993 3. Mingfa Yao, Zheng Chen, Zunqing Zheng, Bo Zhang, Yuan Xing: Study on the controlling strategies of homogeneous charge compression ignition combustion with fuel of dimethyl ether and methanol. FUEL 85, p. 2046-2056. Elsevier 2006 4. Hideyuki Ogawa, Noboru Miyamoto, Naoya Kaneko, Hirokazu Ando: Combustion Control and Operating Range Expansion With Direct Injection of Reaction Suppressors in a Premixed Dme Hccl Engine. SAE 2003-01-0746. 2003 5. Yoshihiko Kanoto, Tetsuo Ohmura, Norimasa Iida: An Investigation of Combustion Control Using EGR for Small and Light HCCI Engine Fuelled With DME. 2007-01-1876. 2007 6. Mingfa Yao, Zheng Chen, Zun-qing Zheng, Bo Zhang, Yuan Xing: Effects of EGR on HCCI Combustion Fuelled with Dimethyl Ether (DME) and Methanol Dual-Fuels. 2005-01-3730. 2005 7. S. Katijani; Z. Chen; M. Oguma; M. Konno: A study of low-compression-ratio dimethyl ether diesel engines. Internal Journal of Engine Research, Volume 3: Number 1: ISSN 1468-0874 8. Troels Dyhr Pedersen, Jesper Schramm: A Study on the Effects of Compression Ratio, Engine Speed and Equivalence Ratio on HCCI Combustion of DME. SAE 2007-01-1860. 2007 9. Ming-fa Yao, Zhao-Lei Zheng, Xia Liang: Numerical Study on the Chemical Reaction Kinetics of DME/Methanol HCCI Combustion Process. SAE 2006-01-1521. 2006 10.Atsumu Tezaki, Hiroyuki Yamada, Mitsuaki Ohtomo: Mechanism Controlling Autoignition Derived From Transient Chemical Composition Analysis in HCCI. SAE 2007-01-1882. 2007 11.Curran, H. J., S. L. Fischer, F. L. Dryer: The Reaction Kinetics of Dimethyl Ether. II: Low-Temperature Pyrolysis and Oxidation in Flow Reactors. Int. J. Chem. Kinet. 32: 741–759, 2000. Lawrence Livermore National Laboratory, Livermore, CA, UCRL-JC-239496. 2000 12.Fischer, S. L., F. L. Dryer, H. J. Curran: The Reaction Kinetics of Dimethyl Ether. I: High-Temperature Pyrolysis and Oxidation in Flow Reactors. Int. J. Chem. Kinet. 32: 713–740, 2000. Lawrence Livermore National Laboratory, Livermore, CA, UCRL-JC-239461. 2000 13.Sato, Yoshio; Nozaki, Shinya; Noda, Toshifumi: The Performance of a Diesel Engine for Light Duty Truck Using a Jerk Type In-Line DME Injection System. SAE paper 2004-01-1862 14.Takayugi Tsuchiya, Yoshio Sato: Development of DME Engine for Heavy-duty Truck. SAE paper 2006-01- 0052. 2006 15.Heywood, John B. : Internal Combustion Engine Fundamentals, McGraw-Hill ISBN 0-07-100499-8 16.Hiroyuki Yamada, Masataka Yoshii, Atsumu Tezaki: Chemical mechanistic analysis of additive effects in homogeneous charge compression ignition of dimethyl ether. Proceedings of the Combustion Institute 30, p. 2773.2780. Elsevier 2004. 17.Hiroyuki Yamada, M Ohtomo, M Yoshii, A Tezaki: Controlling mechanism of ignition enhancing and suppressing additives in premixed compression ignition. Internal Journal on Engine Research Vol. 6, IMechE. 2005 18.Tadanori Yanai, Yoshio Sato, Atsuhiro Kawamura, Hiroshi Oikawa, Shinya Nozaki, Toshifumi Noda, Teruaki Ishikawa: Development and Engine Bench Testing of a Common Rail Type DME Injection System. SAE 2008-08-0501. 2008 Page 20 of 22
Page 1:
Homogeneous Charge Compression Igni
Page 4 and 5:
- 2 - - Table of contents 1 FOREWOR
Page 6 and 7:
- 4 - - 11.5.3 Filtering of sample
Page 8 and 9:
- 6 - - 1 Foreword The work describ
Page 10 and 11:
3 Résumé - 8 - - This thesis is b
Page 12 and 13:
4 Resumé (dansk) - 10 - - Denne af
Page 14 and 15:
5 Introduction - 12 - - 5.1 About H
Page 16 and 17:
- 14 - - 5.3 Scope of investigation
Page 18 and 19:
6 The basics of HCCI combustion - 1
Page 20 and 21:
- 18 - - the cylinder. In HCCI comb
Page 22 and 23:
7 Combustion of DME - 20 - - 7.1 Co
Page 24 and 25:
- 22 - - 8 Description of experimen
Page 26 and 27:
- 24 - - 8.1.3 Piston modifications
Page 28 and 29:
- 26 - - combustion event is often
Page 30 and 31:
- 28 - - however not possible, sinc
Page 32 and 33:
- 30 - - (excess air ratio 3) of ai
Page 34 and 35:
dQ dt = h ⋅ A ⋅ - 32 - - ( T
Page 36 and 37:
- 34 - - In addition, many reaction
Page 38 and 39:
- 36 - - Arrows in the scheme indic
Page 40 and 41:
- 38 - - formaldehyde (CH2O) and fo
Page 42 and 43:
Figure 12: Termination of the low t
Page 44 and 45:
- 42 - - The non-carbon radical act
Page 46 and 47:
10.7 List of species Radicals of hy
Page 48 and 49:
- 46 - - If a frequency analysis of
Page 50 and 51:
- 48 - - 11.5.3 Filtering of sample
Page 52 and 53:
- 50 - - The SPL of the cylinder pr
Page 54 and 55:
Figure 17: Intensity chart for cyli
Page 56 and 57:
- 54 - - 11.7.3 Axial modes Axial w
Page 58 and 59:
- 56 - - A case was set up to make
Page 60 and 61:
12 Simulation of detonation phenome
Page 62 and 63:
- 60 - - provided more ideal condit
Page 64 and 65:
- 62 - - positive in the x- directi
Page 66 and 67:
3,0 x 10 6 2,5 x 10 6 2,0 x 10 6 1,
Page 68 and 69:
- 66 - - A detailed drawing of the
Page 70 and 71:
- 68 - - In the expressions above,
Page 72 and 73:
( 21) ( 22) - 70 - - The mach numbe
Page 74 and 75: ( 25) - 72 - - Δt v = u ⋅ Δx wh
Page 76 and 77: - 74 - - Figure 29: Development in
Page 78 and 79: - 76 - - 12.5 Observations of deton
Page 80 and 81: - 78 - - On figure 34, the individu
Page 82 and 83: - 80 - - • The engine load obtain
Page 84 and 85: - 82 - - 15. Takayugi Tsuchiya, Yos
Page 86 and 87: - 84 - - 15 Appendix A: Reduced sch
Page 88 and 89: 16 Appendix B: Detonation model in
Page 90 and 91: - 88 - - 17 Paper I: The Effect of
Page 92 and 93: - 90 - - 19 Paper III: Reducing HCC
Page 94 and 95: DESCRIPTION OF THE EXPERIMENT OBJEC
Page 96 and 97: Engine modification To obtain a low
Page 98 and 99: Pressure [Mpa] 6 5 4 3 2 1 lambda 2
Page 100 and 101: Pressure [Mpa] 6 5 4 3 2 1 lambda 4
Page 102 and 103: At lambda 4, IMEP peaks at a compre
Page 104: CONCLUSION • It was possible to a
Page 107 and 108: close to the lean limit. HC is comp
Page 109 and 110: Reactions do however not stop entir
Page 111 and 112: METHANOL TEST PROCEDURE In the firs
Page 113 and 114: Page 8 of 22 0 -5 -10 -15 -20 -25
Page 115 and 116: With EGR there was a notable change
Page 117 and 118: Page 12 of 22 9 8 7 6 5 4 3 2 MEOH
Page 119 and 120: Page 14 of 22 250 200 150 100 50 40
Page 121 and 122: EMISSIONS The emissions in table 6
Page 123: Page 18 of 22 15 12 9 6 3 0 1000 RP
Page 127 and 128: PM: Particulate matter THC: Total H
Page 129 and 130: Coupling of pressure waves and reac
Page 131 and 132: chambers which often have this flat
Page 133 and 134: The two piston crowns with chambers
Page 135 and 136: Page 8 of 21 Figure 10: Steel plate
Page 137 and 138: Page 10 of 21 16.7 kW @ 3000 rpm 17
Page 139 and 140: v v, ref T T ref with T and Tref be
Page 141 and 142: dB higher than the 8 cylindrical ch
Page 143 and 144: Page 16 of 21 Flat chamber 7 BTDC 3
Page 145 and 146: Page 18 of 21 diesel type chamber 3
Page 147 and 148: CONCLUSION HCCI combustion generate
Page 150: DTU Mechanical Engineering Section
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