Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies

Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results

ICEF2011-60122 THE EFFECTS OF FUEL CHARACTERISTICS ON STOICHIOMETRIC SPARK-ASSISTED HCCI

ABSTRACT The characteristics of fuel lean HCCI operation using a variety of fuels are well known and have been demonstrated using different engine concepts in the past. In contrast, stoichiometric operation of HCCI is less well documented. Recent studies have highlighted the benefits of operating at a stoichiometric condition in terms of load expansion combined with the applicability of three way catalyst technology to reduce NOx emissions. In this study the characterization of stoichiometric HCCI using gasoline-like fuels was undertaken. The fuels investigated are gasoline, a 50 vol% blend of iso-butanol and gasoline (IB50), and an 85% vol blend of ethanol and gasoline (E85). A single cylinder engine operating with direct injection and spark assist combined with a fully variable hydraulic valve actuation system allowed a wide range of operating parameters to be studied. This included the effects of negative valve overlap duration, intake valve closing and valve lift. Furthermore, the interaction between fuel injection timing and spark and how they can affect the required valve timing to achieve stoichiometric HCCI combustion are also studied. A comprehensive combustion and emissions analysis is conducted using gasoline, IB50 and E85 at an engine speed of 2000rpm over a range of operating loads. The resultant fuel properties which differed in terms of octane rating, fuel oxygenation and heat of vaporization show that stoichiometric HCCI is possible using a range of fuels but that these fuel characteristics do have some effect on the combustion characteristics. How these fuel properties can enable an increased engine operating envelope to be achieved, in comparison with both fuel lean HCCI and conventional spark ignited combustion, is then discussed

Performance, combustion and emissions of a diesel engine operated with reformed EGR. Comparison of diesel and GTL fuelling

This is the post-print version of the final paper published in Fuel. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2008 Elsevier B.V.In this work, the effects of a standard ultra-low sulphur diesel (ULSD) fuel and a new, ultra-clean synthetic GTL (gas-to-liquid) fuel on the performance, combustion and emissions of a single-cylinder, direct injection, diesel engine were studied under different operating conditions with addition of simulated reformer product gas, referred to as reformed EGR (REGR). For this purpose various levels of REGR of two different compositions were tested. Tests with standard EGR were also carried out for comparison. Experiments were performed at four steady state operating conditions and the brake thermal efficiency, combustion process and engine emission data are presented and discussed. In general, GTL fuel resulted in a higher brake thermal efficiency compared to ULSD but the differences depended on the engine condition and EGR/REGR level and composition. The combustion pattern was significantly modified when the REGR level was increased. Although the extent of the effects of REGR on emissions depended on the engine load, it can be generally concluded that an optimal combination of GTL and REGR significantly improved both NOx and smoke emissions. In some cases, NOx and smoke emission reductions of 75% and 60%, respectively, were achieved compared to operation with ULSD without REGR. This offers a great potential for engine manufacturers to meet the requirements of future emission regulations.Shell Global Solutions UK, the Government of Castilla-La Mancha (Spain) and the Royal Thai Government

Technical Issues Associated With the Use of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet

The Oak Ridge National Laboratory (ORNL) supports the U.S. Department of Energy (DOE) in assessing the impact of using intermediate ethanol blends (E10 to E30) in the legacy fleet of vehicles in the U.S. fleet. The purpose of this report is to: (1) identify the issues associated with intermediate ethanol blends with an emphasis on the end-use or vehicle impacts of increased ethanol levels; (2) assess the likely severity of the issues and whether they will become more severe with higher ethanol blend levels, or identify where the issue is most severe; (3) identify where gaps in knowledge exist and what might be required to fill those knowledge gaps; and (4) compile a current and complete bibliography of key references on intermediate ethanol blends. This effort is chiefly a critical review and assessment of available studies. Subject matter experts (authors and selected expert contacts) were consulted to help with interpretation and assessment. The scope of this report is limited to technical issues. Additional issues associated with consumer, vehicle manufacturer, and regulatory acceptance of ethanol blends greater than E10 are not considered. The key findings from this study are given

Enabling High Efficiency Ethanol Engines

Delphi Automotive Systems and ORNL established this CRADA to explore the potential to improve the energy efficiency of spark-ignited engines operating on ethanol-gasoline blends. By taking advantage of the fuel properties of ethanol, such as high compression ratio and high latent heat of vaporization, it is possible to increase efficiency with ethanol blends. Increasing the efficiency with ethanol-containing blends aims to remove a market barrier of reduced fuel economy with E85 fuel blends, which is currently about 30% lower than with petroleum-derived gasoline. The same or higher engine efficiency is achieved with E85, and the reduction in fuel economy is due to the lower energy density of E85. By making ethanol-blends more efficient, the fuel economy gap between gasoline and E85 can be reduced. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has extensive knowledge and experience in powertrain components and subsystems as well as overcoming real-world implementation barriers. ORNL has extensive knowledge and expertise in non-traditional fuels and improving engine system efficiency for the next generation of internal combustion engines. Partnering to combine these knowledge bases was essential towards making progress to reducing the fuel economy gap between gasoline and E85. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, usually on a bi-weekly basis, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided substantial hardware support to the project by providing components for the single-cylinder engine experiments, engineering support for hardware modifications, guidance for operational strategies on engine research, and hardware support by providing a flexible multi-cylinder engine to be used for optimizing engine efficiency with ethanol-containing fuels

Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies

Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results