Author: John O. WaldmanPublisher:
ISBN:
Category :
Languages : en
Pages : 342
Book Description
Investigating the Effects of Direct Fuel Injection During the Negative Value Overlap Period in a Gasoline Fueled HCCI Engine
Author: John O. WaldmanInvestigation Into Expanding the Operating Range in a Gasoline Fueled Negative Valve Overlap HCCI Engine
Author: Dennis G. NitzCost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles
Author: National Research CouncilPublisher: National Academies Press
ISBN: 0309373913
Category : Science
Languages : en
Pages : 812
Book Description
The light-duty vehicle fleet is expected to undergo substantial technological changes over the next several decades. New powertrain designs, alternative fuels, advanced materials and significant changes to the vehicle body are being driven by increasingly stringent fuel economy and greenhouse gas emission standards. By the end of the next decade, cars and light-duty trucks will be more fuel efficient, weigh less, emit less air pollutants, have more safety features, and will be more expensive to purchase relative to current vehicles. Though the gasoline-powered spark ignition engine will continue to be the dominant powertrain configuration even through 2030, such vehicles will be equipped with advanced technologies, materials, electronics and controls, and aerodynamics. And by 2030, the deployment of alternative methods to propel and fuel vehicles and alternative modes of transportation, including autonomous vehicles, will be well underway. What are these new technologies - how will they work, and will some technologies be more effective than others? Written to inform The United States Department of Transportation's National Highway Traffic Safety Administration (NHTSA) and Environmental Protection Agency (EPA) Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) emission standards, this new report from the National Research Council is a technical evaluation of costs, benefits, and implementation issues of fuel reduction technologies for next-generation light-duty vehicles. Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles estimates the cost, potential efficiency improvements, and barriers to commercial deployment of technologies that might be employed from 2020 to 2030. This report describes these promising technologies and makes recommendations for their inclusion on the list of technologies applicable for the 2017-2025 CAFE standards.
Fuel Effect on HCCI Engine with Negative Valve Overlap
Author: Keitaro OkunoGasoline-like Fuel Effects on High-load, Boosted HCCI Combustion Employing Negative Valve Overlap Strategy
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In recent years a number of studies have demonstrated that boosted operation combined with external EGR is a path forward for expanding the high load limit of homogeneous charge compression ignition (HCCI) operation with the negative valve overlap (NVO) valve strategy. However, the effects of fuel composition with this strategy have not been fully explored. In this study boosted HCCI combustion is investigated in a single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), laboratory pressurized intake air, and a fully-variable hydraulic valve actuation (HVA) valve train. Three fuels with significant compositional differences are investigated: regular grade gasoline (RON = 90.2), 30% ethanol-gasoline blend (E30, RON = 100.3), and 24% iso-butanol-gasoline blend (IB24, RON = 96.6). Results include engine loads from 350 to 800 kPa IMEPg for all fuels at three engine speeds 1600, 2000, and 2500 rpm. All operating conditions achieved thermal efficiency (gross indicated efficiency) between 38 and 47%, low NOX emissions (0.1 g/kWh), and high combustion efficiency (96.5%). Detailed sweeps of intake manifold pressure (atmospheric to 250 kPaa), EGR (0 25% EGR), and injection timing are conducted to identify fuel-specific effects. The major finding of this study is that while significant fuel compositional differences exist, in boosted HCCI operation only minor changes in operational conditions are required to achieve comparable operation for all fuels. In boosted HCCI operation all fuels were able to achieve matched load-speed operation, whereas in conventional SI operation the fuel-specific knock differences resulted in significant differences in the operable load-speed space. Although all fuels were operable in boosted HCCI, the respective air handling requirements are also discussed, including an analysis of the demanded turbocharger efficiency.
In-Cylinder Reaction Chemistry and Kinetics During Negative Valve Overlap Fuel Injection Under Low-Oxygen Conditions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Fuel injection into the negative valve overlap (NVO) period is a common method for controlling combustion phasing in homogeneous charge compression ignition (HCCI) as well as other forms of advanced combustion. During this event, at least a portion of the fuel hydrocarbons can be converted to products containing significant levels of H2 and CO, as well as other short chain hydrocarbons by means of thermal cracking, water-gas shift, and partial oxidation reactions, depending on the availability of oxygen and the time-temperature-pressure history. The resulting products alter the autoignition properties of the combined fuel mixture for HCCI. Fuel-rich chemistry in a partial oxidation environment is also relevant to other high efficiency engine concepts (e.g., the dedicated EGR (D-EGR) concept from SWRI). In this study, we used a unique 6-stroke engine cycle to experimentally investigate the chemistry of a range of fuels injected during NVO under low oxygen conditions. Fuels investigated included iso-octane, iso-butanol, ethanol, and methanol. Products from NVO chemistry were highly dependent on fuel type and injection timing, with iso-octane producing less than 1.5% hydrogen and methanol producing more than 8%. We compare the experimental trends with CHEMKIN (single zone, 0-D model) predictions using multiple kinetic mechanisms available in the current literature. Our primary conclusion is that the kinetic mechanisms investigated are unable to accurately predict the magnitude and trends of major species we observed.
HCCI and CAI Engines for the Automotive Industry
Author: Hua ZhaoPublisher: CRC Press
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 562
Book Description
Homogeneous charge compression ignition (HCCI)/controlled auto-ignition (CAI) has emerged as one of the most promising engine technologies with the potential to combine fuel efficiency and improved emissions performance, offering reduced nitrous oxides and particulate matter alongside efficiency comparable with modern diesel engines. Despite the considerable advantages, its operational range is rather limited and controlling the combustion (timing of ignition and rate of energy release) is still an area of on-going research. Commercial applications are, however, close to reality. HCCI a.
Homogeneous Charge Compression Ignition Engines, 2007
Author: Publisher:
ISBN:
Category : Internal combustion engines
Languages : en
Pages : 592
Book Description
Effects of Negative Valve Overlap on HCCI Combustion and Its Use in the Control of HCCI Combustion Timing
Author: Alexander E. SchrammPublisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 114
Book Description
Homogeneous charge compression ignition (HCCI) combustion can produce higher efficiencies and lower emissions when compared to tradition spark or compression ignition engines. This study reports an experimental investigation into the effects of valve timings on HCCI combustion conditions. Using a single cylinder engine with state-of-the-art electromagnetic variable valve timing (EVVT) fully independent valves, a series of tests are conducted with varying negative valve overlap (NVO). The in-cylinder residual trapped by the NVO causes an advance in combustion timing, a shortening of burn duration as well as increase in load and increase in brake specific fuel consumption. Asymmetric valve timings are also investigated and show complex behavior with high sensitivity of combustion timing in certain operating ranges. Finally, these strategies are implemented as a set of feedback controllers including a proportional-integral (PI) controller and a feedforward with integral action controller. Both controllers have good tracking for step changes in combustion timing setpoint with the feedforward controller providing a rise time of just four cycles.
Author: Jacob Richard Zuehl