An Investigation of the Fuel Economy of a Drive Cycle Developed Using the Road Load Energy Criterion

Efforts to mitigate climate change include lowering of greenhouse gas emissions by reducing fuel consumption in the transport sector. Various vehicle technologies and interventions for better fuel economy eventually require chassis dynamometer testing using drive cycles for validation. As such, the methodology to generate these drive cycles from on-road data should produce drive cycles that closely represent actual on-road driving from the fuel economy standpoint. This study presents a comparison of the fuel economy measured from a drive cycle developed using road load energy as a major assessment criterion and the actual on-road fuel economy of a 2013 Isuzu Crosswind utility vehicle used in the UV Express transport fleet in Metro Manila, Philippines. In this approach to drive cycle construction from on-road data, the ratio of the total road load energy of the generated drive cycle to that of the on-road trip is made the same ratio as their respective durations. On-road velocity and fuel consumption were recorded as the test vehicle traversed the 42.5 km. Sucat to Lawton route and vice versa in Metro Manila. Gathered data were processed to generate drive cycles using the modified Markov Chain approach. Three drive cycles of decreasing duration, based on the practicality of testing on a chassis dynamometer, were generated using three arbitrary data compression ratios. These drive cycles were tested using the same vehicle on the chassis dynamometer and compared with the on-road data using road load energy, fuel economy, average speed, and maximum acceleration. For the 893-seconds drive cycle generated, the road load energy error was 3.93% and fuel economy difference of 1.14%. For the 774-seconds cycle generated, the road load energy error was 4.34% and fuel economy difference was 0.91%. For the 664-seconds drive cycle, the road load energy error was 3.68% and fuel economy difference was 0.91%. On-road fuel economy for the 42.5-km. route averaged over nine round trips was 8.785 km/L. Based on the results, the road load energy criterion approach of drive cycle construction methodology can generate drive cycles which can very closely estimate on-road fuel economy.

A comparison of bottom-up methods for estimating institutional building energy use to inform resource and emission reduction strategies

Bottom-up engineering models are an emerging approach for evaluating energy efficiency solutions at district or regional scales. More flexible than statistical models, bottom-up models allow planners to quantitatively evaluate energy efficiency and supply options, leading to more effective policies and energy demand solutions that better reflect our changing climate. This thesis compares two bottom-up methods for exploring resource and emission reduction strategies in the institutional sector: the Wireframe method and the Reference method. These methods are compared by predicting the annual consumption of post-secondary student residences in Southern Ontario and measuring the error of each, compared with the 2013 mandatory energy report data from the Ministry of Energy of Ontario. Both methods produced aggregate energy error ranges of 5% to 12% in a detailed analysis, suggesting that they are both effective for large-scale energy reduction studies.

A comparison of bottom-up methods for estimating institutional building energy use to inform resource and emission reduction strategies

Bottom-up engineering models are an emerging approach for evaluating energy efficiency solutions at district or regional scales. More flexible than statistical models, bottom-up models allow planners to quantitatively evaluate energy efficiency and supply options, leading to more effective policies and energy demand solutions that better reflect our changing climate. This thesis compares two bottom-up methods for exploring resource and emission reduction strategies in the institutional sector: the Wireframe method and the Reference method. These methods are compared by predicting the annual consumption of post-secondary student residences in Southern Ontario and measuring the error of each, compared with the 2013 mandatory energy report data from the Ministry of Energy of Ontario. Both methods produced aggregate energy error ranges of 5% to 12% in a detailed analysis, suggesting that they are both effective for large-scale energy reduction studies.

Terrestrial exoplanet simulator: an error optimal planetary system integrator that permits close encounters

ABSTRACT We present Terrestrial Exoplanet Simulator (tes), a new n-body integration code for the accurate and rapid propagation of planetary systems in the presence of close encounters. tes builds upon the classic Encke method and integrates only the perturbations to Keplerian trajectories to reduce both the error and runtime of simulations. Variable step size is used throughout to enable close encounters to be precisely handled. A suite of numerical improvements is presented that together make tes optimal in terms of energy error. Lower runtimes are found in the majority of test problems considered when compared to direct integration using ias15. tes is freely available.

Energy-Based Automatic Determination of Buffer Region in the Divide-and-Conquer Second-Order Møller-Plesset Perturbation Theory

In the linear-scaling divide-and-conquer (DC) electronic structure method, each subsystem is calculated together with the neighboring buffer region, the size of which affects the energy error introduced by the fragmentation in the DC method. The DC self-consistent field calculation utilizes a scheme to automatically determine the appropriate buffer region that is as compact as possible for reducing the computational time while maintaining acceptable accuracy (<i>J. Comput. Chem.</i> <b>2018</b>, <i>39</i>, 909). To extend the automatic determination scheme of the buffer region to the DC second-order Møller-Plesset perturbation (MP2) calculation, a scheme for estimating the subsystem MP2 correlation energy contribution from each atom in the buffer region is proposed. The estimation is based on the atomic orbital Laplace MP2 formalism. Based on this, an automatic buffer determination scheme for the DC-MP2 calculation is constructed and its performance for several types of systems is assessed.

Explicit symplectic-like integration with corrected map for inseparable Hamiltonian

ABSTRACT Symplectic algorithms are widely used for long-term integration of astrophysical problems. However, this technique can only be easily constructed for separable Hamiltonian, as preserving the phase-space structure. Recently, for inseparable Hamiltonian, the fourth-order extended phase-space explicit symplectic-like methods have been developed by using the Yoshida’s triple product with a mid-point map, where the algorithm is more effective, stable and also more accurate, compared with the sequent permutations of momenta and position coordinates, especially for some chaotic case. However, it has been found that, for the cases such as with chaotic orbits of spinning compact binary or circular restricted three-body system, it may cause secular drift in energy error and even more the computation break down. To solve this problem, we have made further improvement on the mid-point map with a momentum-scaling correction, which turns out to behave more stably in long-term evolution and have smaller energy error than previous methods. In particular, it could obtain a comparable phase-space distance as computing from the eighth-order Runge–Kutta method with the same time-step.

A Proposed Estimation of the Expanded Uncertainty of Charpy Impact Testers

Uncertainty estimation is one of the very delicate tasks in the field of measurements. For the purpose of calibration of Charpy impact testing machines, it is necessary to evaluate and identify the expanded uncertainty. Factors affecting the uncertainty estimations are; the uncertainty of reference force and length measuring devices and its long-term instability (drift), machine resolution, rated energy error, indicated energy error, losses due to the drag of the pointer, friction losses in the bearing and air resistance, and other geometric parameters. In this study, the uncertainty estimation of the Charpy impact machines is based on the direct verification used in the BS DIN ISO 148-2 standard.

Energy-Based Automatic Determination of Buffer Region in the Divide-Andconquer Second-Order Møller-Plesset Perturbation Theory

In the linear-scaling divide-and-conquer (DC) electronic structure method, each subsystem is calculated together with the neighboring buffer region, the size of which affects the energy error introduced by the fragmentation in the DC method. The DC self-consistent field calculation utilizes a scheme to automatically determine the appropriate buffer region that is as compact as possible for reducing the computational time while maintaining acceptable accuracy (<i>J. Comput. Chem.</i> <b>2018</b>, <i>39</i>, 909). To extend the automatic determination scheme of the buffer region to the DC second-order Møller-Plesset perturbation (MP2) calculation, a scheme for estimating the subsystem MP2 correlation energy contribution from each atom in the buffer region is proposed. The estimation is based on the atomic orbital Laplace MP2 formalism. Based on this, an automatic buffer determination scheme for the DC-MP2 calculation is constructed and its performance for several types of systems is assessed.