This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Homogeneous Charge Compression Ignition with a Free Piston: A New Approach to Ideal Otto Cycle Performance
Annotation ability available
Sector:
Language:
English
Abstract
Sandia National Laboratories has been investigating a new, integrated approach to generating electricity with ultra low emissions and very high efficiency for low power (30 kW) applications such as hybrid vehicles and portable generators.
Our approach utilizes a free piston in a double-ended cylinder. Combustion occurs alternately at each cylinder end, with intake/exhaust processes accomplished through a two stroke cycle. A linear alternator is mounted in the center section of the cylinder, serving to both generate useful electrical power and to control the compression ratio by varying the rate of electrical generation. Thus, a mechanically simple geometry results in an electronically controlled variable compression ratio configuration.
The capability of the homogeneous charge compression ignition combustion process employed in this engine with regards to reduced emissions and improved thermal efficiency has been investigated using a rapid compression expansion machine. Eight different fuels, including propane, natural gas, hydrogen, methanol, n-pentane, hexane, n-heptane, and isooctane have been used at low equivalence ratio (ϕ ∼ 0.35) and initial temperatures of 25°C, 50°C and 70°C.
The results indicate that the cycle thermal efficiency can be significantly improved (56% measured) relative to current combustion systems, while low NOx emissions are possible (<10 PPM). HC and CO emissions must be controlled through some aftertreatment technology. The primary cause of this high conversion efficiency is nearly constant volume combustion at high compression ratio (∼ 30:1).
Recommended Content
Authors
Topic
Citation
Van Blarigan, P., Paradiso, N., and Goldsborough, S., "Homogeneous Charge Compression Ignition with a Free Piston: A New Approach to Ideal Otto Cycle Performance," SAE Technical Paper 982484, 1998, https://doi.org/10.4271/982484.Also In
References
- Edson, M. H. Taylor, C. F. “The Limits of Engine Performance - Comparison of Actual and Theoretical Cycles,” Digital Calculations of Engine Cycles, SAE Prog. in Technology 7 65 81 1964
- Van Blarigan, P. “Development of a Hydrogen Fueled Internal Combustion Engine Designed for Single Speed/Power Operation,” SAE Paper 961690 1996
- Edson, M. H. “The Influence of Compression Ratio and Dissociation on Ideal Otto Cycle Engine Thermal Efficiency,” Digital Calculations of Engine Cycles, SAE Prog. in Technology 7 49 64 1964
- Caris, D. F. Nelson, E. E. “A New Look at High Compression Engines,” SAE Transactions 67 112 124 1959
- Overington, M. T. Thring, R. H. “Gasoline Engine Combustion - Turbulence and the Combustion Chamber,” SAE Paper 810017 1981
- Muranaka, Y. T. Ishida, T. “Factors Limiting the Improvement in Thermal Efficiency of S.I. Engine at Higher Compression Ratio,” SAE Transactions 96 526 536 1987
- Das, L. M. “Hydrogen Engines: A View of the Past and a Look Into the Future,” International Journal of Hydrogen Energy 15 6 425 443 1990
- Van Blarigan, P. Green, R. “NO x Emission Data Verified in a Hydrogen Fueled Engine,” Combustion Research Facility News 17 4 January February 1995
- Onishi, S. Jo, S. H. Shoda, K. Jo, P. D. Kato, Satoshi “Active Thermo-Atmospheric Combustion (ATAC) - A New Combustion Process for Internal Combustion Engines,” SAE Paper 790501 1979
- Karim, G. A. Watson, H. C. “Experimental and Computational Considerations of the Compression Ignition of Homogeneous Fuel-Oxidant Mixtures,” SAE Paper 710133 1971
- Alperstein, M. Swim, W. B. Schweitzer, P. H. “Fumigation Kills Smoke - Improves Diesel Performance,” SAE Transactions 66 574 588 1958
- Thring, R. H. “Homogeneous-Charge Compression-Ignition Engines,” SAE Paper 892068 1989
- Najt, P. M. Foster, D. E. “Compression-Ignited Homogeneous Charge Combustion,” SAE Paper 830264 1983
- Christensen, M. Johansson, B. Amneus, P. Mauss, F. “Supercharged Homogeneous Charge Compression Ignition,” SAE Paper 980787 1998
- Christensen, M. Johansson, B. Einewall, P. “Homogeneous Charge Compression Ignition (HCCI) Using Isooctane, Ethanol and Natural Gas - A Comparison with Spark Ignition Operation,” SAE Paper 972874 1997
- Underwood, A. F. “The GMR 4-4 ‘Hyprex’ Engine - A Concept of the Free-Piston Engine for Automotive Use,” SAE Paper 570032 1957
- Klotsch, P. “Ford Free-Piston Engine Development,” SAE Paper 590045 1959
- Baruah, P. C. “A Free-Piston Engine Hydraulic Pump for an Automotive Propulsion System,” SAE Paper 880658 1988
- Achten, P. A. J. “A Review of Free Piston Engine Concepts,” SAE 941776 1994
- Lee, W. Schaefer, H. J. “Analysis of Local Pressures, Surface Temperatures and Engine Damages under Knock Conditions,” SAE Transactions 92 511 523 1983
- Maly, R. R. Klein, R. Peters, N. Konig, G. “Theoretical and Experimental Investigation of Knock Induced Surface Destruction,” SAE Transactions 99 99 137 1990
- Park, P. Keck, J. C. “Rapid Compression Machine Measurements of Ignition Delays for Primary Reference Fuels,” SAE Paper 900027 1990