Exergy is a thermodynamic concept that ponders the quality of energy. It evaluates the irreversibilities of a machine, demonstrating its capacity to perform work associated with energy conversion. This article focuses on directing public policies and vehicle development toward their most proper usage worldwide. In the urban mobility scenario, there is an obvious demand to decrease greenhouse gas (GHG) emissions. In addition, the internal combustion engine (ICE) experiences considerable energy losses through heat exchange through the radiator and exhaust flow gases, which are not considerable in battery electric vehicles (BEVs) since there are no exhaust gases subsequent to combustion, nor combustion itself. This work presents longitudinal dynamics simulations of passenger vehicles to understand the magnitude of exergy destruction in ICEVs and BEVs, considering the Brazilian and European Union electric energy mix. Overall, the method can be applied to any other country. The simulation and model parameters were configured to match production road vehicles commercialized in the Brazilian market based on different versions of the same model. Two vehicle dynamic duty cycles were used, one relating to urban usage and another to highway usage, resulting in an overall exergy efficiency of around 50–51% for BEVs considering the exergy destruction in power plants. In contrast, ICE has an average efficiency of 20% in the urban cycle and around 30% in the highway cycle. By comparing the overall equivalent CO₂ emissions, it is possible to conclude that EVs in the European energy matrix produce more GHG than ICE vehicles running on ethanol in Brazil. Nevertheless, there are increasing uses of coal, natural gas, and oil thermal electric power plants, raising the question of how the transition may occur with a general increase in electrification since there is an increasing electric expenditure in all sectors of society, and the renewable energy plants may not meet all of the demand.

Lubricant friction modifier additives are used on lower viscosity engine oils to mitigate boundary friction. This work presents the development of a graphene-based material as an oil friction modifier additive, from formulation to actual vehicle tests. The graphene material was initially characterized using scanning electron microscopy (SEM) and Raman spectroscopy, which revealed the predominance of graphene nanoplatelets (GNPs) with an average of nine layers. After functionalization, two GNP additive variants were initially mixed with a fully formulated SAE 0W-20 engine oil and tribologically evaluated using reciprocating sliding tests at 40 and 120 °C and Hertzian pressure up to 1.2 GPa when both variants presented friction reduction. Then, the GNP additive variant with better performance was evaluated in a vehicle emission test using a fully formulated 5W-20 SAE oil as a reference. The addition of 0.1% of GNPs reduced fuel consumption by 2.6% in urban conditions and 0.8% in highway ones. The urban test cycle was FTP75 and higher benefits of the GNP additive occurred especially on the test start, when the engine and oil were still cold and on test portions where the vehicle speed was lower.

The optimization of passenger car efficiency is an important contribution to GHG emissions mitigation. This global warming concern is pushing technological solutions to reduce vehicle fuel consumption and consequently CO₂ emissions. In this work, the impacts of engine lubricants with lower viscosity and friction modifier additive in a light-vehicle with a spark ignition engine were numerically simulated and experimentally validated. The substitution of a baseline 5W40 lubricant by a lower viscosity 5W20 proposal resulted in 2.9% lower fuel consumption in a combined cycle. This fuel consumption improvement is enhanced to 6.1% with a 0W16 lubricant with friction modifier. A 1D simulation model based on lubricant temperature and viscosity impact on engine friction was developed and presented good experimental correlation in combined cycle for 5W20, showing a 7% lower fuel consumption advantage than the experimental results. The numerical simulation advantage was 38% lower than experimental results for 0W16 that contains friction modifier, as the additive impact was not considered in this mathematical model.

Climate constraints impose greenhouse gas emissions mitigation, and passenger cars have considerable contributions to contribute to this. To improve the engine efficiency of vehicles equipped with conventional powertrains, many technologies are available but with limited individual contribution. The experimental assessment of some technology regarding fuel economy measurement results is sometimes lower than test uncertainties. This study proposes a methodology to compensate the fuel economy for two test uncertainties: vehicle speed variations and battery recharging. The proposed method can be applied when investigating the effects of different vehicle design changes, including engine power cell design. In this work, the proposed method is demonstrated on the test of two oils: one 5W40, the other 5W20, both without FM. Applying the proposed methodology to experimental results, the expected higher influence of oil viscosity on urban conditions could be observed, and the experimental results presented a much better correlation with the vehicle numerical simulation. Applying the proposed compensation, fuel savings of using the 5W20 in comparison to the 5W40 oil was 3.5% under urban conditions and 2.0% on highways.

The present and appropriate concern regarding climate changes resulting from the combustion of fossil fuels in light passenger vehicles raises the necessity to develop appropriate instruments to investigate probable and feasible solutions for fleet decarbonization. Given the direct relationship between fossil fuel consumption and greenhouse gas emissions have historically been determined through experimental tests in the laboratory following standard cycles, to enhance the vehicle’s energy efficiency these should be complemented by numerical simulation tools, as they demonstrate fast response and adequate correlation to experimentation. In this aspect, one of the biggest challenges of numerical simulation is quantifying the impact of the various phenomena that affect the vehicle operation during the cold phase, in which the internal combustion engine loses efficiency. This study proposes a thermodynamic model for simulating the fuel consumption of light vehicles during the cold phase of operation. Measured lubricant temperature, ignition spark retardation, exhaust valve timing, and coolant temperature in the vehicles along the drive cycle are the required input data for the model. This thermodynamic procedure makes it possible to quantify the impact on fuel consumption while driving the vehicle in cold operation. The cold phase, with a 505 s duration, is responsible for approximately a 21% increase in fuel consumption in a standard urban drive cycle. It is considered that the shorter the route, the more pronounced and significant the cold phenomena are, and the impact of vehicles frequently driven on short urban routes can be accurately estimated for future analyses.