The work reported in this thesis was conducted to study the effects of variable valve actuation on combustion, emissions, and fuel economy in a modern design of 4-valve per cylinder SI engine. The use of statistically-based procedures for the design of experiments allowed a limited number of tests to be used to explore a wide region of each of the experimental variables. A series of steady-flow tests was conducted to assess the effects of valve lift on flow past the valves and the nature of any in-cylinder motion generated. Results from the former were incorporated into a filling and emptying model that allowed levels of trapped residuals and pumping work to be estimated for different valve strategies. The in-cylinder motion tests explored asymmetric valve lifts, that is to say where the two valves were opened by a different amount. These results allowed a pair of response surfaces to be established to model the intensity of both axial and barrel swirl within the cylinder over the range of valve lifts. Engine tests were conducted in two parts. The first explored the effects of changes in exhaust event phasing, intake event phasing, intake event duration, and peak intake valve lift. The design of the experiment allowed linear, quadratic, and interactions between the variables to be modelled using regression analysis. Statistical analysis allowed the most influential factors (both main effects and interactions) to be identified. Contour plots of the modelled response were used to draw conclusions about the nature of the response surface and to isolate the effects of valve opening and closure angles as well as overlap. The results were correlated with those from the steady-flow tests and from the computer model. The strategy for the second phase of tests was chosen after considering the previous results. The steady-flow tests indicated that there was considerable potential for enhancing in-cylinder motion by adopting a valve deactivation strategy and combining it with a low lift of the active intake valve. The second phase investigated the use of such a technique in conjunction with large overlaps over a range of duration of the intake valve event. The results from both phases of engine tests indicated possible strategies to reduce emissions from future engines.

Dans le contexte où le secteur automobile apparaît comme l’un des principaux émetteurs de gaz à effet de serre, des efforts doivent être apportés pour répondre à des normes antipollution de plus en plus contraignantes. L’objectif de la thèse est alors de développer un système qui aide le conducteur à adopter globalement une conduite plus économique, et qui plus est, écologique et sécuritaire. Notre approche se différencie des études et systèmes déjà existants par la stratégie utilisée. Celle-ci prend à la fois en compte les caractéristiques du véhicule, celles de l’infrastructure (pente, dévers, courbure) et surtout les contraintes sécuritaires que doit respecter le conducteur (limitation de vitesse légale, distance intervéhiculaire). Partant de ces informations, le problème d’optimisation de la consommation en carburant est formulé et résolu par la programmation dynamique. La stratégie de calcul en ligne est par la suite adoptée pour rendre le système adaptatif aux conditions de trafic. C’est ainsi que, sur la base de cette stratégie, le couplage entre le problème de sécurité routière et de réduction de consommation est réalisé. Des expérimentations de ce système informatif suggestif sur véhicule prototype montrent que le suivi des consignes, données par le système, est tout à fait réalisable par le conducteur. Ces essais confirment aussi le potentiel d’économie en carburant et l’amélioration de la sécurité grâce à notre système. En comparaison avec le style d’éco-conduite des conducteurs, l’économie en carburant en moyenne est de 7.5% et peut atteindre 12.9% et des réductions des dépassements de vitesse de 50% en moyenne et atteint près de 80% pour certains conducteurs. / In the context where the automobile sector represents one of the major greenhouse gas emitters, significant efforts should be made to answer the demand for increasingly restricted emissions standards. The object of this thesis is to develop a fuel-efficient support tool which helps the driver to adopt more economical, ecological and safe driving. our approach differs from studies in the literature by the introduction of a strong coupling of fuel optimization and safety maintaining problems. As inputs of the system, we use the vehicle states such as the vehicle and engine speeds, the gear used, the road geometry and information related to safety (inter-vehicle speed, traffic conditions, legal speed limit...). Optimisation algorithms compute in real-time a speed and gear profile for fuel economy and improvement of safety.. The experimental results of this informative and suggestive system show that instructions, given by the system, are quite feasible by the driver. These tests also confirm the potential for fuel economy and the safety

This study is concentrated on modelling and developing the controller for the light-duty hybrid electric truck. The hybrid electric vehicle has advantages in fuel economy. However, there have been relatively few studies on commercial HEVs, whilst a considerable number of studies on the hybrid electric system have been conducted in the field of passenger cars. So the current status and the methodologies to develop the LD hybrid electric truck model have been studied through the literature review. The modelling process used in this study is divided into three major stages. The first stage is to determine the structure of the hybrid electric truck and define the hardware. The second is the component modelling using the AMESim simulation tool to develop a forward facing model. In order to complete the component modelling, the information and data were collected from various sources including references and ADVISOR. The third stage is concerned with the controller which was written in Simulink. This was run in a co-simulation with the AMESim vehicle model. Through the initial simulation, the charge-sustaining performance of this controller was verified and improved. Finally, the simulations for the complete model were carried out over a number of drive cycles, such as CBDTRUCK, JE05, and TRL LGV drive cycle, to evaluate and analyse the effect on the fuel economy and the vehicle performance by the engine operating zone and the EM power capacity. The report presents a comparison of the fuel efficiency of the conventional vehicle and the LD hybrid electric truck. The results obtained by the simulation show the feasibility to build the complete vehicle with the designed controller.

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The automotive industry is in a state of flux at the moment. Traditional combustion engine technologies are becoming challenged by newer, more efficient and environmentally friendly propulsion methods. These include bio-fuel, hybrid, and hydrogen fuel-cell technologies. Propulsion alone, however, is not the only area where improvements can be made in vehicle efficiency. Current vehicle research and development focuses heavily on propulsion systems with relatively few resources dedicated to auxiliary systems. These auxiliary systems, however, can have a significant impact on overall vehicle efficiency and fuel economy. The objective of this work is to improve the efficiency of a Fuel Cell Electric Vehicle (FCEV) through intelligent auxiliary system control. The analysis contained herein is applicable to all types of vehicles and may find applications in many vehicle architectures. A survey is made of the various types of alternative fuels and vehicle architectures from conventional gasoline vehicles to hybrids and fuel cells. Trends in auxiliary power systems and previous papers on control of these systems are discussed. The FCEV developed by the University of Waterloo Alternative Fuels Team (UWAFT) is outlined and the design process presented. Its powertrain control strategy is analyzed with a proposal for modifications as well as the addition of an auxiliary control module to meet the aforementioned objectives. Simulations are performed to predict the efficiency and fuel economy gains that can potentially be realized using these proposed techniques. These gains prove to be significant, with an almost 2% improvement realized through intelligent control of the air conditioning compressor, and further gains possible through other auxiliary power reduction techniques.

The automotive industry is in a state of flux at the moment. Traditional combustion engine technologies are becoming challenged by newer, more efficient and environmentally friendly propulsion methods. These include bio-fuel, hybrid, and hydrogen fuel-cell technologies. Propulsion alone, however, is not the only area where improvements can be made in vehicle efficiency. Current vehicle research and development focuses heavily on propulsion systems with relatively few resources dedicated to auxiliary systems. These auxiliary systems, however, can have a significant impact on overall vehicle efficiency and fuel economy. The objective of this work is to improve the efficiency of a Fuel Cell Electric Vehicle (FCEV) through intelligent auxiliary system control. The analysis contained herein is applicable to all types of vehicles and may find applications in many vehicle architectures. A survey is made of the various types of alternative fuels and vehicle architectures from conventional gasoline vehicles to hybrids and fuel cells. Trends in auxiliary power systems and previous papers on control of these systems are discussed. The FCEV developed by the University of Waterloo Alternative Fuels Team (UWAFT) is outlined and the design process presented. Its powertrain control strategy is analyzed with a proposal for modifications as well as the addition of an auxiliary control module to meet the aforementioned objectives. Simulations are performed to predict the efficiency and fuel economy gains that can potentially be realized using these proposed techniques. These gains prove to be significant, with an almost 2% improvement realized through intelligent control of the air conditioning compressor, and further gains possible through other auxiliary power reduction techniques.

A Hybrid Electric Vehicle (HEV) is a complex electro-mechanical-chemical system that involves two or more energy sources. The inherent advantages of HEVs are their increased fuel economy, reduced harmful emissions and better vehicle performance. The extent of improvement in fuel economy and vehicle performance greatly depends on selecting optimal component sizes. The complex interaction between the various components makes it difficult to size specific components manually or analytically. So, simulation-based multi-variable design optimization is a possible solution for such kind of system level design problems. The multi-modal, noisy and discontinuous nature of the Hybrid Vehicle design requires the use of derivativeree global algorithms because the derivative-based local algorithms work poorly with such design problems. In this thesis, a Hybrid Vehicle is optimized using various Global Algorithms ? DIviding RECTangles (DIRECT), Simulated Annealing (SA), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO). The objective of this study is to increase the overall fuel economy on a composite of city and highway driving cycle and to improve the vehicle performance. The performance of each algorithm is compared on a six variable hybrid electric vehicle design problem. Powertrain System Analysis Tool (PSAT), a state-of-the-art powertrain simulator, developed in MATLAB/Simulink environment by Argonne National Laboratory is used as the vehicle simulator. Further, a Hybrid algorithm that is a combination of global and local algorithm is developed to improve the convergence of the global algorithms. The hybrid algorithm is tested on two simple mathematical functions to check its efficiency.

No description available.

Energy management strategies for charge sustaining hybrid electric vehicles reduce fuel power consumption from the engine and electric power consumption from the motor while meeting output power demand. The equivalent consumption minimization strategy is a real time control strategy which uses backward facing models and an equivalence ratio to calculate the lowest total fuel power consumption. The equivalence ratio quantifies the fuel power to battery power conversion process of the hybrid electric vehicle components and therefore quantifies electric power consumption in terms of fuel power consumption. The magnitude of the equivalence ratio determines when the hybrid electric vehicle commands a conventional, electric, or hybrid mode of operation. The equivalence ratio therefore influences the capability of the control strategy to meet charge sustaining performance. Willans line models quantify the input power to output power relationship for powertrain and drivetrain components with a linear relationship and a constant offset. The hybrid electric vehicle model performance is characterized using three Willans line models in the equivalent consumption minimization strategy. The slope of the Willans line models, or marginal efficiency, is used to generate a single equivalence ratio which quantifies the fuel to battery energy conversion process for the hybrid electric vehicle. The implementation of a Willans line based equivalent consumption minimization strategy reduces total fuel power consumption while achieving charge sustaining performance over mild and aggressive drive cycles. / Master of Science / The charge sustaining hybrid electric vehicle in this paper generates output power with an internal combustion engine powered by a fuel tank and an electric traction motor powered by a battery pack. Hybrid electric vehicle energy management strategies generate torque commands to meet output power demand based on the minimum total input power from both the fuel tank and battery pack. Willans line models simplify the energy management strategy by quantifying the output power to input power relationship, or efficiency, of each component with a linear slope and constant offset. The use of Willans line models quantifies the efficiency of the hybrid electric vehicle with three linear relationships. Energy management strategies also ensure the battery pack starts and ends at the same operating condition to maintain charge sustaining performance. Charge sustaining hybrid electric vehicles therefore use the battery pack as an energy buffer and do not need to be charged by an external power supply since all energy comes from fuel. The output to input power relationship of Willans line models quantifies the power conversion of the hybrid electric vehicle and coupled to a term which accounts for changes in the battery pack. The use of Willans line models in hybrid electric vehicles effectively generates torque commands to the engine and motor while improving fuel economy and maintaining charge sustaining performance.

EPA testing methods for calculation of fuel economy label ratings, which were revised beginning in 2008, use equations that weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. The equations incorporate effects with varying weightings into the final fuel consumption, which are explained in this thesis paper, including illustrations from testing. Some of the test results used in the computation come from individual phases within the certification driving cycles. This methodology causes additional complexities for hybrid electric vehicles, because although they are required to have charge-balanced batteries over the course of a full drive cycle, they may have net charge or discharge within the individual phases. The fundamentals of studying battery charge-balance are discussed in this paper, followed by a detailed investigation of the implications of per-phase charge correction that was undertaken through testing of a 2010 Toyota Prius at Argonne National Laboratory's vehicle dynamometer test facility. Using the charge-correction curves obtained through testing shows that phase fuel economy can be significantly skewed by natural charge imbalance, although the end effect on the fuel economy label is not as large. Finally, the characteristics of the current 5-cycle fuel economy testing method are compared to previous methods through a vehicle simulation study which shows that the magnitude of impact from mass and aerodynamic parameters vary between labeling methods and vehicle types. / Master of Science