Showing papers on "Engine efficiency published in 2019"
TL;DR: In this paper, the authors review the historical evolution and major metallurgical advancements of high temperature materials in heavy duty diesel engines up to the current state of the art, focusing on materials in the engine block, cylinder heads, pistons, valves, and exhaust components.
118 citations
TL;DR: In this paper, an experimental investigation on diesel-biogas dual fuel (DF) engine is presented based on energy and exergy analyses, where the effects of change in compression ratio (CR), exhaust gas recirculation (EGR) and EGR temperature on the performance and emission characteristics of DF engine have been studied.
79 citations
02 Jul 2019
TL;DR: This work analyzes work quantifiers for a heat-pumped three-level maser and derives the respective engine efficiencies, finding that in the classical limit of strong maser intensities the engine efficiency converges towards the Scovil--Schulz-DuBois maser efficiency, irrespective of the work quantifier.
Abstract: One of the fundamental questions in quantum thermodynamics concerns the decomposition of energetic changes into heat and work. Contrary to classical engines, the entropy change of the piston cannot be neglected in the quantum domain. As a consequence, different concepts of work arise, depending on the desired task and the implied capabilities of the agent using the work generated by the engine. Each work quantifier---from ergotropy to non-equilibrium free energy---has well defined operational interpretations. We analyse these work quantifiers for a heat-pumped three-level maser and derive the respective engine efficiencies. In the classical limit of strong maser intensities the engine efficiency converges towards the Scovil--Schulz-DuBois maser efficiency, irrespective of the work quantifier.
60 citations
TL;DR: In this paper, a Cooperative Fuel Research (CFR) engine with varying fuel-air equivalence ratio (φ) was evaluated with three alternative fuels, natural gas, ethanol, and syngas, at compression ratio of 8:1 and engine speed of 1200 rev/min.
59 citations
TL;DR: In this paper, the authors investigated the environmental, operational and economic performance of the methanol partially premixed combustion concept at slow speed operation of a ship to find a solution for the shipping emission effect on the coastal settlements while do not increase the risk and expense of the engine operation on the ships.
47 citations
TL;DR: In this paper, the authors proposed a methodology that identifies the burn inside the bowl using the inflection points of the heat release rate, which can separate the fast combustion stage from the rest of the combustion event compared to the conventional spark-ignition theory that could not.
47 citations
TL;DR: In this paper, a modified dual fuel spark ignition engine was used to study the performance of port injection of ethanol and direct injection of gasoline surrogates (toluene reference fuel).
45 citations
TL;DR: In this paper, the authors explored the possibility of the reformed-exhaust gas recirculation (R-EGR) concept for increased efficiency of methanol engines by using waste heat for driving fuel reforming.
38 citations
TL;DR: A homogeneous compression ignition (HCCI) engine is taken for numerical investigation on the application of renewable fuels contained blends of methanol and DME with the base diesel fuel, which will be replaced with diesel in different percentages as mentioned in this paper.
38 citations
TL;DR: In this paper, experiments with the use of PPC and two different EGR routes were performed on a light duty Euro 6 2 L diesel engine and the results showed that by combining EGR from both routes, generally, an optimum gas exchange efficiency can be found by splitting the EGR through both routes.
37 citations
30 Sep 2019
TL;DR: In this article, the effect of tumble flow on engine in-cylinder performance and its mechanism is investigated. And the results show that higher tumble ratio leads to faster blue flame development and less yellow flame generation, which indicates an increase in flame burning rate and a decrease of soot formation.
TL;DR: In this article, the authors investigated the magnitude and phasing of lean-burn natural-gas spark-ignition combustion inside a diesel geometry and found that a more advanced phase of the late burning stage relative to the fast-burn stage would result in a more optimal combustion environment, which would further improve the engine efficiency and probably reduce carbon monoxide and unburned hydrocarbon emissions.
TL;DR: In this article, the potential of coated pistons in reducing fuel consumption and pollutant emissions of a 1.6※l automotive diesel engine was investigated by utilizing a one-dimensional Computational Fluid Dynamics engine simulation code.
TL;DR: In this article, the performance of Pro Diesel with pure diesel fuel and retail hydrotreated vegetable oil (HVO) was analyzed under medium engine speed and brake torque load regimes (30-120 Nm).
Abstract: This article presents our research results on the physical-chemical and direct injection diesel engine performance parameters when fueled by pure diesel fuel and retail hydrotreated vegetable oil (HVO). This fuel is called NexBTL by NESTE, and this renewable fuel blends with a diesel fuel known as Pro Diesel. A wide range of pure diesel fuel and NexBTL100 blends have been tested and analyzed: pure diesel fuel, pure NexBTL, NexBTL10, NexBTL20, NexBTL30, NexBTL40, NexBTL50, NexBTL70 and NexBTL85. The energy, pollution and in-cylinder parameters were analyzed under medium engine speed (n = 2000 and n = 2500 rpm) and brake torque load regimes (30–120 Nm). AVL BOOST software was used to analyze the heat release characteristics. The analysis of brake specific fuel consumption showed controversial results due to the lower density of NexBTL. The mass fuel consumption decreased by up to 4%, and the volumetric consumption increased by up to approximately 6%. At the same time, the brake thermal efficiency mainly increased by approximately 0.5–1.4%. CO, CO2, NOx, HC and SM were analyzed, and the change in CO was negligible when increasing NexBTL in the fuel blend. Higher SM reduction was achieved while increasing the percentage of NexBTL in the blends.
TL;DR: A novel energy management strategy for a PEM fuel cell excavator with a supercapacitor/battery hybrid power source to concurrently account for power supply performance from the hybrid power sources as well as from fuel cells, and battery lifespan is proposed.
Abstract: Construction machines are heavy-duty equipment and a major contributor to the environmental pollution. By using only electric motors instead of an internal combustion engine, the problems of low engine efficiency and air pollution can be solved. This paper proposed a novel energy management strategy for a PEM fuel cell excavator with a supercapacitor/battery hybrid power source. The fuel cell is the main power supply for most of the excavator workload while the battery/supercapacitor is the energy storage device, which supplies additional required power and recovers energy. The whole system model was built in a co-simulation environment, which is a combination of MATLAB/Simulink and AMESim software, where the fuel cell, battery, supercapacitor model, and the energy management algorithm were developed in a Simulink environment while the excavator model was designed in an AMESim environment. In this work, the energy management strategy was designed to concurrently account for power supply performance from the hybrid power sources as well as from fuel cells, and battery lifespan. The control design was proposed to distribute the power demand optimally from the excavator to the hybrid power sources in different working conditions. The simulation results were presented to demonstrate the good performance of the system. The effectiveness of the proposed energy management strategy was validated. Compared with the conventional strategies where the task requirements cannot be achieved or system stability cannot be accomplished, the proposed algorithms perfectly satisfied the working conditions.
TL;DR: The energy cost of shortcuts to adiabatic expansions or compressions of a harmonic oscillator, the power strokes of a quantum Otto engine, and conditions for which inclusive power of the primary system and exclusive power control system are proportional are found.
Abstract: We assess the energy cost of shortcuts to adiabatic expansions or compressions of a harmonic oscillator, the power strokes of a quantum Otto engine. Difficulties to identify the cost stem from the interplay between different parts of the total system (the primary system —the particle— and the control system) and definitions of work (exclusive and inclusive). While attention is usually paid to the inclusive work of the microscopic primary system, we identify the energy cost as the exclusive work of the total system, which, for a clear-cut scale disparity between a microscopic primary system and a macroscopic control system, coincides with the exclusive work for the control system alone. We redefine the “engine efficiency” taking into account this cost. Our working horse model is an engine based on an ion in a Paul trap with power strokes designed via shortcuts to adiabaticity. Opposite to the paradigm of slow-cycle reversible engines with vanishing power and maximal efficiency, this fast-cycle engine increases the microscopic power at the price of a vanishing efficiency. The Paul trap fixes the gauge for the primary system, resulting in a counterintuitive evolution of its inclusive power and internal energy. Conditions for which inclusive power of the primary system and exclusive power control system are proportional are found.
TL;DR: In this paper, an optically accessible, small-bore single-cylinder diesel engine was used to quantify the ignition kernel development and flame growth rate of single and double injection strategies, supported by electronically excited hydroxyl (OH*) imaging.
TL;DR: In this paper, a single-cylinder automotive-size gasoline compression ignition (GCI) engine running on a double-injection mode was investigated, where both the first injection proportion and fuel ignition quality were varied considering their expected influence on premixed charge preparation.
TL;DR: The results of a case study prove that the proposed framework can effectively integrate the system off-design performance when designing a system, and downsizing the equipment to match the probability of occurrence of the possible off- design operating conditions can lead to a medium-sized system that is much more favorable in terms of economic performance over its whole lifetime.
TL;DR: In this article, the authors evaluated the performance of a Stage V compliant engine layout which can avoid dedicated aftertreatment devices for NOx, and demonstrated that extremely high injection pressures in conjunction with the use of after injection as a soot reduction technique, was capable of achieving a 50% smoke reduction with a more than acceptable engine efficiency degradation.
TL;DR: Both the proposed ARBS and the established PRBS strategies are compared over an extended duty cycle consisting of both urban and highway segments and the results show that ARBS can achieve high MPGe with different thresholds for the boundary between the motor region and the engine region.
Abstract: This paper proposes an Adaptive Rule-Based Energy Management Strategy (ARBS EMS) for a parallel hybrid electric vehicle (HEV). The aim of the strategy is to facilitate the aftermarket hybridization of medium- and heavy-duty vehicles. ARBS can be deployed online to optimize fuel consumption without any detailed knowledge of the engine efficiency map of the vehicle or the entire duty cycle. The proposed strategy improves upon the established Preliminary Rule-Based Strategy (PRBS), which has been adopted in commercial vehicles, by dynamically adjusting the regions of operations of the engine and the motor. It prevents the engine from operating in highly inefficient regions while reducing the total equivalent fuel consumption of the vehicle. Using an HEV model developed in Simulink®, both the proposed ARBS and the established PRBS strategies are compared over an extended duty cycle consisting of both urban and highway segments. The results show that ARBS can achieve high MPGe with different thresholds for the boundary between the motor region and the engine region. In contrast, PRBS can achieve high MPGe only if this boundary is carefully established from the engine efficiency map. This difference between the two strategies makes the ARBS particularly suitable for aftermarket hybridization where full knowledge of the engine efficiency map may not be available.
TL;DR: In this paper, a literature review of existing technologies available to optimize the energy performance of diesel engines and diesel generators in order to reduce the cost of electricity, to increase the diesel engine efficiency and to decrease their fuel consumption and greenhouse gases (GHG) emissions.
Abstract: The electrical instability that frequently distinguishes the isolated networks and depends on diesel generators to supply their energy requirements leads to an operation of the diesel generator in a transient dynamic condition and/or at low loads. In addition, extended operation of the diesel generator at partial load develops the condensation of combustion residues on the engine cylinder walls, which, after a certain time, increases friction, reduces the efficiency of the equipment and increases its fuel consumption. On the other hand, recent regulatory changes have led to ever more stringent and evolving emission standards. Among these, the International Maritime Organization (IMO) and the Environmental Protection Agency (EPA) have implemented emission standards in order to reduce exhaust gas emitted by marine diesel engines. To phase lower emission engines as soon as possible, a Tier system was adopted. This paper presents a literature review of existing technologies available to optimize the energy performance of diesel engines and diesel generators in order to reduce the cost of electricity, to increase the diesel engine efficiency and to decrease their fuel consumption and greenhouse gases (GHG) emissions. The proposed optimization methodologies are based on the application of Pre-treatment, Internal treatment and Post-treatment technologies for diesel engines and on the application of mechanical and electrical technologies for diesel power generators (DPGs). The list of references given at the end of the paper should offer aids for students and researchers working in this field.
01 Aug 2019
TL;DR: Simulation results for a real-world congested driving cycle show that the engine thermal effect and the cabin heating requirement can significantly influence the optimal behavior for the power management, and substantial potential on fuel saving can be achieved by the i-PTM optimization as compared to conventional power and thermal management strategies.
Abstract: Cabin heating demand and engine efficiency degradation in cold weather lead to considerable increase in fuel consumption of hybrid electric vehicles (HEVs), especially in congested traffic conditions. This paper presents an integrated power and thermal management (i-PTM) scheme for the optimization of power split, engine thermal management, and cabin heating of HEVs. A control-oriented model of a power split HEV, including power and thermal loops, is developed and experimentally validated against data collected from a 2017 Toyota Prius HEV. Based on this model, the dynamic programming (DP) technique is adopted to derive a bench-mark for minimal fuel consumption, using 2-dimensional (power split and engine thermal management) and 3-dimensional (power split, engine thermal management, and cabin heating) formulations. Simulation results for a real-world congested driving cycle show that the engine thermal effect and the cabin heating requirement can significantly influence the optimal behavior for the power management, and substantial potential on fuel saving can be achieved by the i-PTM optimization as compared to conventional power and thermal management strategies.
TL;DR: In this article, the effects of Reactivity Controlled Compression Ignition (RCCI) application on engine combustion, performance and emissions in a diesel generator were investigated, in which safflower oil derived biodiesel and diesel mixtures were used as the high reactivity fuel (primary fuel) and gasoline as the low reactive fuel (low reactive fuel).
TL;DR: In this paper, a metal engine with modern architecture and an optical engine were evaluated using multiple injections and it was shown that the point with optimized multiple injections is of higher efficiency than a single injection.
TL;DR: In this paper, a 1D simulation model was set up to investigate the mechanism why methane could suppress detonation and super-knock, and the experiment and simulation results showed that replacing the fuel from iso-octane or gasoline to methane while keeping other conditions identically could transfer detonation combustion mode to flame propagation.
TL;DR: In this article, a baseline diesel engine has been modeled using a gas dynamic software taking special care of the heat transfer processes in the exhaust, and different strategies for exhaust ports and turbine thermal insulation, which are evaluated in a representative range of steady-state operating conditions.
TL;DR: In this paper, in-cylinder air-fuel stratification and combustion is evaluated in a CNG-fuelled IC engine using a transient, three-dimensional, computational fluid dynamic (CFD) model.
TL;DR: In this article, first and second law thermodynamics analysis were applied to experiments with gasoline compression ignition at an engine speed of 1038 rpm and brake mean effective pressure of 1.4 MPa on a 12.4 L multi-cylinder heavy-duty diesel engine.