Download or read book Dynamic Modeling and Transient Control of Homogeneous Charge Compression Ignition Engines written by Stelios Karagiorgis and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Control of a Homogeneous Charge Compression Ignition Engine written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A homogenous charge compression ignition engine is operated by compressing a charge mixture of air, exhaust and fuel in a combustion chamber to an autoignition condition of the fuel. The engine may facilitate a transition from a first combination of speed and load to a second combination of speed and load by changing the charge mixture and compression ratio. This may be accomplished in a consecutive engine cycle by adjusting both a fuel injector control signal and a variable valve control signal away from a nominal variable valve control signal. Thereafter in one or more subsequent engine cycles, more sluggish adjustments are made to at least one of a geometric compression ratio control signal and an exhaust gas recirculation control signal to allow the variable valve control signal to be readjusted back toward its nominal variable valve control signal setting. By readjusting the variable valve control signal back toward its nominal setting, the engine will be ready for another transition to a new combination of engine speed and load.

Download or read book Control and Robustness Analysis of Homogeneous Charge Compression Ignition Using Exhaust Recompression written by Hsien-Hsin Liao and published by Stanford University. This book was released on 2011 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been an enormous global research effort to alleviate the current and projected environmental consequences incurred by internal combustion (IC) engines, the dominant propulsion systems in ground vehicles. Two technologies have the potential to improve the efficiency and emissions of IC engines in the near future: variable valve actuation (VVA) and homogeneous charge compression ignition (HCCI). IC engines equipped with VVA systems are proven to show better performance by adjusting the valve lift and timing appropriately. An electro-hydraulic valve system (EHVS) is a type of VVA system that possesses full flexibility, i.e., the ability to change the valve lift and timing independently and continuously, making it an ideal rapid prototyping tool in a research environment. Unfortunately, an EHVS typically shows a significant response time delay that limits the achievable closed-loop bandwidth and, as a result, shows poor tracking performance. In this thesis, a control framework that includes system identification, feedback control design, and repetitive control design is presented. The combined control law shows excellent performance with a root-mean-square tracking error below 40 [Mu]m over a maximum valve lift of 4 mm. A stability analysis is also provided to show that the mean tracking error converges to zero asymptotically with the combined control law. HCCI, the other technology presented in this thesis, is a combustion strategy initiated by compressing a homogeneous air-fuel mixture to auto-ignition, therefore, ignition occurs at multiple points inside the cylinder without noticeable flame propagation. The result is rapid combustion with low peak in-cylinder temperature, which gives HCCI improved efficiency and reduces NOx formation. To initiate HCCI with a typical compression ratio, the sensible energy of the mixture needs to be high compared to a spark ignited (SI) strategy. One approach to achieve this, called recompression HCCI, is by closing the exhaust valve early to trap a portion of the exhaust gas in the cylinder. Unlike a SI or Diesel strategy, HCCI lacks an explicit combustion trigger, as autoignition is governed by chemical kinetics. Therefore, the thermo-chemical conditions of the air-fuel mixture need to be carefully controlled for HCCI to occur at the desired timing. Compounding this challenge in recompression HCCI is the re-utilization of the exhaust gas which creates cycle-to-cycle coupling. Furthermore, the coupling characteristics can change drastically around different operating points, making combustion timing control difficult across a wide range of conditions. In this thesis, a graphical analysis examines the in-cylinder temperature dynamics of recompression HCCI and reveals three qualitative types of temperature dynamics. With this insight, a switching linear model is formulated by combining three linear models: one for each of the three types of temperature dynamics. A switching controller that is composed of three local linear feedback controllers can then be designed based on the switching model. This switching model/control formulation is tested on an experimental HCCI testbed and shows good performance in controlling the combustion timing across a wide range. A semi-definite program is formulated to find a Lyapunov function for the switching model/control framework and shows that it is stable. As HCCI is dictated by the in-cylinder thermo-chemical conditions, there are further concerns about the robustness of HCCI, i.e., the boundedness of the thermo-chemical conditions with uncertainty existing in the ambient conditions and in the engine's own characteristics due to aging. To assess HCCI's robustness, this thesis presents a linear parameter varying (LPV) model that captures the dynamics of recompression HCCI and possesses an elegant model structure that is more amenable to analysis. Based on this model, a recursive algorithm using convex optimization is formulated to generate analytical statements about the boundedness of the in-cylinder thermo-chemical conditions. The bounds generated by the algorithm are also shown to relate well to the data from the experimental testbed.

Download or read book Cost Effectiveness and Deployment of Fuel Economy Technologies for Light Duty Vehicles written by National Research Council and published by National Academies Press. This book was released on 2015-09-28 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Modeling and Control of Homogeneous Charge Compression Ignition Engines with High Dilution written by Chia-Jui Chiang and published by . This book was released on 2006 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Actuation Strategies for Cycle to cycle Control of Homogeneous Charge Compression Ignition Combustion Engines written by Adam F. Jungkunz and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mounting evidence of anthropogenic climate change necessitates a significant effort to improve the internal combustion (IC) engine and reduce its adverse environmental impacts resulting from its ubiquitous use powering ground transportation. Homogenous Charge Compression Ignition (HCCI) engines present a promising opportunity to reduce the environmental consequences of using IC engines by reusing exhaust from one engine cycle to initiate combustion on the following engine cycle. The presence of high retained exhaust ratios in HCCI engines results in dilute, low-temperature combustion that achieves greater efficiencies and lower CO2 and NOx emissions than conventional spark-ignited or diesel engines. However, three critical obstacles prevent them from being widely adopted: first, unlike conventional IC engines, HCCI engines lack a direct combustion trigger to determine when combustion occurs, and that lack of a direct trigger makes specifying combustion timing challenging. Second, the high quantities of retained exhaust create a strong physical link between engine cycles, resulting in undesirable dynamics that could potentially lead to engine misfire at certain operating conditions. Finally, the high quantities of retained exhaust also prevent the engine from inducting as much fuel and air as possible, limiting the load range of the engine. This dissertation addresses all three of those obstacles by investigating the abilities of different actuators to control combustion timing and improve the dynamics at certain HCCI operating conditions that could be used to expand the load range of HCCI engines. A simple, physical model that represents one engine cycle as a discrete-time, nonlinear system captures the oscillatory dynamics present at certain HCCI operating conditions on an experimental engine. The physical model provides physical intuition about the sources driving the oscillations and the control actions needed to reduce them. A linearized version of the model depicts the source of those oscillations on a root locus, and shows that a negative real axis pole in a discrete-time, linear dynamical system drives the oscillations. Three different actuators, exhaust valve closing timing, pilot fuel injection timing, and main fuel injection mass, each reduce the oscillations. For each actuator, a linearization of the physical model illustrates how each actuator can be used with simple linear control laws to improve the dynamics at HCCI operating conditions. Then, the actuators are compared to each other on three aspects: the difficulty of the control problem associated with using the particular actuator to reduce the oscillations, the difficulty of implementing the actuator in a production vehicle, and the effectiveness of each actuator at reducing the oscillations.

Download or read book Control and Robustness Analysis of Homogeneous Charge Compression Ignition Using Exhaust Recompression written by Hsien-Hsin Liao and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been an enormous global research effort to alleviate the current and projected environmental consequences incurred by internal combustion (IC) engines, the dominant propulsion systems in ground vehicles. Two technologies have the potential to improve the efficiency and emissions of IC engines in the near future: variable valve actuation (VVA) and homogeneous charge compression ignition (HCCI). IC engines equipped with VVA systems are proven to show better performance by adjusting the valve lift and timing appropriately. An electro-hydraulic valve system (EHVS) is a type of VVA system that possesses full flexibility, i.e., the ability to change the valve lift and timing independently and continuously, making it an ideal rapid prototyping tool in a research environment. Unfortunately, an EHVS typically shows a significant response time delay that limits the achievable closed-loop bandwidth and, as a result, shows poor tracking performance. In this thesis, a control framework that includes system identification, feedback control design, and repetitive control design is presented. The combined control law shows excellent performance with a root-mean-square tracking error below 40 [Mu]m over a maximum valve lift of 4 mm. A stability analysis is also provided to show that the mean tracking error converges to zero asymptotically with the combined control law. HCCI, the other technology presented in this thesis, is a combustion strategy initiated by compressing a homogeneous air-fuel mixture to auto-ignition, therefore, ignition occurs at multiple points inside the cylinder without noticeable flame propagation. The result is rapid combustion with low peak in-cylinder temperature, which gives HCCI improved efficiency and reduces NOx formation. To initiate HCCI with a typical compression ratio, the sensible energy of the mixture needs to be high compared to a spark ignited (SI) strategy. One approach to achieve this, called recompression HCCI, is by closing the exhaust valve early to trap a portion of the exhaust gas in the cylinder. Unlike a SI or Diesel strategy, HCCI lacks an explicit combustion trigger, as autoignition is governed by chemical kinetics. Therefore, the thermo-chemical conditions of the air-fuel mixture need to be carefully controlled for HCCI to occur at the desired timing. Compounding this challenge in recompression HCCI is the re-utilization of the exhaust gas which creates cycle-to-cycle coupling. Furthermore, the coupling characteristics can change drastically around different operating points, making combustion timing control difficult across a wide range of conditions. In this thesis, a graphical analysis examines the in-cylinder temperature dynamics of recompression HCCI and reveals three qualitative types of temperature dynamics. With this insight, a switching linear model is formulated by combining three linear models: one for each of the three types of temperature dynamics. A switching controller that is composed of three local linear feedback controllers can then be designed based on the switching model. This switching model/control formulation is tested on an experimental HCCI testbed and shows good performance in controlling the combustion timing across a wide range. A semi-definite program is formulated to find a Lyapunov function for the switching model/control framework and shows that it is stable. As HCCI is dictated by the in-cylinder thermo-chemical conditions, there are further concerns about the robustness of HCCI, i.e., the boundedness of the thermo-chemical conditions with uncertainty existing in the ambient conditions and in the engine's own characteristics due to aging. To assess HCCI's robustness, this thesis presents a linear parameter varying (LPV) model that captures the dynamics of recompression HCCI and possesses an elegant model structure that is more amenable to analysis. Based on this model, a recursive algorithm using convex optimization is formulated to generate analytical statements about the boundedness of the in-cylinder thermo-chemical conditions. The bounds generated by the algorithm are also shown to relate well to the data from the experimental testbed.

Download or read book Investigating the Effects of Internally Trapped Residuals on the Performance of a Homogeneous Charge Compression Ignition HCCI Engine written by Aaron David Attebery and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Homogeneous charge compression ignition (HCCI) combustion introduces great opportunity for decreased emissions along with greater engine efficiencies. Implementing an innovative combustion mode such as HCCI presents a great challenge for the engine research community. One such challenge is controlling the innate cyclic variability from this chemical kinetics controlled auto-ignition event when transitioning to or from a SI operating mode. This work includes the study of cycle-to-cycle dynamics that occur within the partial burn regime of an HCCI engine as it approaches the misfire limit. Within this regime there are many successive incomplete combustion events that will impact the next cycle through the fuel/air residual, the chemical kinetics, and the pressure-temperature history of the cylinder during the combustion process. A better understanding of this process will provide information relevant to developing control methods for multi-mode operating strategies. Experiments were conducted using a single cylinder HCCI engine operating in an unstable combustion regime in order to observe cyclic variability using rapid exhaust pressure and temperature measurements to appropriately capture any deterministic behavior of the combustion dynamics. On-board syn-gas strategies were also explored by injecting a reactive species gas, carbon-monoxide, directly into the cylinder in order to perturb the intake charge and study the effects this mass injection had on the onset of combustion in HCCI. This could be utilized as one method of control by an engine control unit in order to push the limits of unstable combustion as well as keep the engine within stable operating regions"--Abstract, Leaf iii

Download or read book Addressing the Influence of Carbon Monoxide on the Behavior of an HCCI Engine written by Allen Charles Ernst and published by . This book was released on 2016 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Homogeneous Charge Compression Ignition (HCCI) may be the next leap of improvement to internal combustion engines due to its decreased emissions and improved engine efficiencies. However, such a jump possesses challenges owing to its strict reliance on the inherent physics that dictate start of combustion and limit the reach of stable operation. This work investigates the role and fundamental influence of carbon monoxide on the cycle-to-cycle combustion dynamics present in the region of incomplete combustion that frames the limited HCCI operating region. An improved understanding will open doors to enhanced control methodologies and an expanded stable operating envelope. A constant volume chemical kinetics simulation was developed utilizing an established skeletal PRF mechanism in order to predict product species evolution in an HCCI engine under incomplete combustion conditions. The predicted product species amounts were harnessed to determine internally trapped residual carbon monoxide mass amounts that would be carried to the next engine cycle. These amounts became the basis for an experimental investigation on a single cylinder HCCI engine running on a high octane primary reference fuel. Cyclically resolved, in-cylinder active-specie injections were employed at partial burn operation to explore the effects of carbon monoxide on engine performance and its resultant cyclic dynamics. Observations made through detailed cyclic performance data, return maps, and symbol sequencing analysis help to expose a significant impact of carbon monoxide on HCCI combustion development and the potential it may possess to drive HCCI combustion as a future dynamic control mechanism"--Abstract, page iii.

Download or read book Control of a Multicylinder Homogeneous Charge Compression Ignition Engine written by William Lee Gans and published by . This book was released on 2003 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance and Control of the Homogeneous Charge Compression Ignition HCCI Engine written by Jan-Ola Olsson and published by . This book was released on 2002 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Homogeneous Charge Compression Ignition Engine with Emphasis on Combustion Timing and Reaction Rate written by Arunim Bhattacharya and published by . This book was released on 2017 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: HCCI engines are a class of engines which use high compression ratio to ignite a charge of air-fuel mixture, essentially eliminating the need for spark plugs. This contrasts with diesel engines (although HCCI can be used for diesel engines) where the fuel is injected near the top dead center of the compression stroke regime. Gasoline HCCI engines are of significance because, it attempts to improve the characteristics of the engine for example the thermal efficiency. High compression ratio comes with higher thermal efficiency, yet the peak temperature remains low enough to have low production rates of harmful oxides of nitrogen and formation of soot. However, there are certain challenges associated with such type of engine, one of which and perhaps the most important of all is how to control the combustion rate. Flow dynamics and chemical-kinetics analysis, is essential to predict combustion timing, duration, and rate. The objective of this study is to analyze a HCCI engine using, simulation analysis models including a three-dimensional CFD simulation model. Simulation analysis is carried out using a generic HCCI engine, initially with simplified chemical kinetics, and then using detailed chemical kinetics and using RANS turbulence CFD model. A sensitivity analysis of the effect of RPM on the combustion time, burn duration, heat release, efficiency and emission concentration are carried out.

Download or read book Closed loop Control of a Multicylinder Homogeneous Charge Compression Ignition Engine Using Fast Thermal Management and Ion Sensors written by Parag Mehresh and published by . This book was released on 2005 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fuel Effects on Homogeneous Charge Compression Ignition Combustion written by Jacob Richard Zuehl and published by . This book was released on 2009 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book HCCI and CAI Engines for the Automotive Industry written by Hua Zhao and published by CRC Press. This book was released on 2007-09-10 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Managing Transient Behaviors of a Dual Mode Spark Ignition Controlled Auto Ignition Engine with a Variable Valve Timing System written by Halim Gustiono Santoso and published by . This book was released on 2004 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gasoline Homogeneous Charge Compression Ignition (HCCI) engine has the potential of providing better fuel economy and emissions characteristics than current spark ignition engines. One implementation of this technology employs a Variable Valve Timing (VVT) system and is also often referred to as Controlled Auto Ignition (CAI) combustion in the literature. The objective of the study can be divided into two topics. First, the dynamic nature of load trajectory and several important phenomena in CAI mode were investigated. Second, the issues encountered during mode transition between SI and CAI regime were considered. Despite wide-open-throttle operation, pumping loss in CAI mode was not negligible. A major source of pumping loss in CAI mode was the heat transfer to cylinder wall during the recompression process due to the high in-cylinder residual gas temperature. The influence of fuel air equivalence ratio on combustion stability was analyzed to explain the misfires phenomenon in fuel rich condition during transient operation. Heat release analysis has been conducted to characterize the combustion process in CAI mode. Large variations of the 50% burned point due to fluctuation of residual gas mass and temperature were observed. Small step changes in valve timings (EVC, EVO, and IVC) and fueling resulted in a new steady state within 3-4 engine cycles at 1500 rpm. These small step changes are reversible in nature. Sudden large step change in load required much longer time to reach steady state due to the time required for thermal stabilization. Misfires were observed in large low-load-to-high-load step change but not in high-load-to-low-load step change.

Download or read book Combustion Control of the Homogeneous Charge Compression Ignition Engine written by Göran Haraldsson and published by . This book was released on 2003 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: