Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

Dahham, Rami Y.; Wei, Haiqiao; Pan, Jiaying

doi:10.3390/en15176222

Cited by 37 publications

(21 citation statements)

References 416 publications

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“…ICEs will still be the major power source for decades to come, regardless of the penetration of AFVs (alternative fuel vehicles), because the latter must start from very low bases [2]. Furthermore, ICEs can still benefit from newer technologies to increase their efficiency and performance [57][58][59]. The two main directions are improving conventional designs, such as the natural aspired engine, and engine downsizing with turbocharging.…”

Section: Resultsmentioning

confidence: 99%

Toward a Direct CO2 Tax for the Brazilian LDV Fleet

Mosquim,

Collaço,

Mady

2024

Energies

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Policies for reducing the environmental impact of light-duty vehicles are restarting in Brazil. While electrification attracts more engagement than other forms of carbon footprint reduction, the use of ethanol could achieve faster gains with the existing infrastructure. The prominence of entry-level cars has reduced, which may be due to several factors, making these vehicles uneconomical for manufacturers to produce. This situation is different from those in other countries. It is our premise that other modes, such as walking, cycling, and public transportation, are the main methods of decarbonization. However, most need improvements in terms of security and attractiveness for consumers. Hence, the internal combustion engine will dominate the Brazilian fleet for quite some time. This article discusses the policies used to incentivize the implementation of entry-level vehicles in contrast with electric vehicles based on regression models of the Brazilian fleet. By providing a history of the 1.0 L engine in Brazil, this article debates replacing the indirect displacement taxation with direct CO2 taxation, which can make the Brazilian entry-level car practical again, with the possibility of adopting some incentives. This logic will cause a fleet renovation and more rational energy use. The distinguishing feature of this article is the proposition of possible public policies based on a regression model of the national fleet. The key findings show that the fleet is getting older and heavier, consuming more energy, and emitting greater amounts of CO2 per unit of displacement, for example, 1.0 L. Furthermore, the carbon footprint of the electricity mix is similar to that of the produced ethanol (from well to wheel, the carbon footprint is the same). This highlights the necessity for national policy adjustments and effective public policies to reduce carbon emissions from the energy sector for small vehicles.

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Section: Resultsmentioning

confidence: 99%

Toward a Direct CO2 Tax for the Brazilian LDV Fleet

Mosquim,

Collaço,

Mady

2024

Energies

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“…These results verified the need for immediate action, both for energy saving and temperature control to avoid the formation of compounds toxic to human health (PAHs), derived from the pyrolysis of the leaves and wood combustion gases. In comparison, the efficiency of combustion engines, for instance, despite being modern, is around 35 -40% (DAHHAM et al, 2022) and the mate processing would be around 50% efficient, despite being rustic. However, the restrictions on energy consumption from the environmental and economic point of view, require efforts both for the diagnosis and designing of new projects for more energy efficient mate processing.…”

Section: Thermal Balance Of the Mate Processingmentioning

confidence: 99%

Thermal condition of mate (Ilex paraguariensis) processing

et al. 2023

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The Ilex paraguariensis is a species native to Brazil, Paraguay and Argentine, valued by its positive effects on human health. Mate processing consists of the following stages: pre-drying (rapid drying at high temperature, known as sapeco operation), drying, and milling. In order to verify the current process and to propose future improvements to the mate processing, thermal and mass balance analysis were applied to industrial mate processing units. Results showed that the consumption of energy in sapeco and drying operations exceeds the calorific input necessary for these operations. These results verify the need for a change in the management of temperatures in the sapeco and drying stages of mate processing in order to optimize the consumption of energy, resulting in lower costs, with positive effects on the quality of the mate products.

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“…By contrast, certain regions are planning explicit engine bans decades in the future; however, that approach tends to be less popular among citizens, so certain governments may opt instead to "effectively ban" engines through unrealistic emissions and/or fuel economy thresholds. For the majority of countries, engines will continue being prevalent, and local environments will benefit from engines incorporating more advanced combustion and gas flow techniques [31], as well as more efficient aftertreatment systems (including reduced cold start emissions) [28], burning alternative fuels (natural gas, hydrogen, methanol, biodiesel, etc.) [32][33][34][35], and incorporating WHR [36].…”

Section: Regulations and Policymentioning

confidence: 99%

Review of Organic Rankine Cycles for Internal Combustion Engine Waste Heat Recovery: Latest Decade in Review

Sprouse

2024

Sustainability

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The last decade (2013–2023) was the most prolific period of organic Rankine cycle (ORC) research in history in terms of both publications and citations. This article provides a detailed review of the broad and voluminous collection of recent internal combustion engine (ICE) waste heat recovery (WHR) studies, serving as a necessary follow-on to the author’s 2013 review. Research efforts have targeted diverse applications (e.g., vehicular, stationary, and building-based), and it spans the full gamut of engine sizes and fuels. Furthermore, cycle configurations extend far beyond basic ORC and regenerative ORC, particularly with supercritical, trilateral, and multi-loop ORCs. Significant attention has been garnered by fourth-generation refrigerants like HFOs (hydrofluoroolefins), HFEs (hydrofluoroethers), natural refrigerants, and zeotropic mixtures, as research has migrated away from the popular HFC-245fa (hydrofluorocarbon). Performance-wise, the period was marked by a growing recognition of the diminished performance of physical systems under dynamic source conditions, especially compared to steady-state simulations. Through advancements in system control, especially using improved model predictive controllers, dynamics-based losses have been significantly reduced. Regarding practically minded investigations, research efforts have ameliorated working fluid flammability risks, limited thermal degradation, and pursued cost savings. State-of-the-art system designs and operational targets have emerged through increasingly sophisticated optimization efforts, with some studies leveraging “big data” and artificial intelligence. Major programs like SuperTruck II have further established the ongoing challenges of simultaneously meeting cost, size, and performance goals; however, off-the-shelf organic Rankine cycle systems are available today for engine waste heat recovery, signaling initial market penetration. Continuing forward, next-generation engines can be designed specifically as topping cycles for an organic Rankine (bottoming) cycle, with both power sources integrated into advanced hybrid drivetrains.

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Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

Cited by 37 publications

References 416 publications

Toward a Direct CO2 Tax for the Brazilian LDV Fleet

Toward a Direct CO2 Tax for the Brazilian LDV Fleet

Thermal condition of mate (Ilex paraguariensis) processing

Review of Organic Rankine Cycles for Internal Combustion Engine Waste Heat Recovery: Latest Decade in Review

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