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In the automotive industry, engine downsizing has been widely accepted as an enabler to improving the fuel economy and reducing the CO₂ emissions. The Atkinson cycle is one of the key technologies. In this paper, the Atkinson cycle with different expansion ratios are compared and analyzed. The investigation is compared with the benchmark whose expansion and compression ratio are identical. The aim is to understand the inherent characteristics of the over-expansion and its effect on the engine performance and emissions. The simulation results show that, the Atkinson cycle produces higher efficiency due to over-expansion. The Atkinson cycle has higher internal EGR compared with the benchmark at equivalent conditions, which contributes to lower the NOx and CO emissions.

Research studies show that 2-methylfuran (MF) is a promising gasoline alternative regarding its positive effect on engine performance and emissions. Before using pure MF in spark ignition engines, it is more likely to be used in a low-level blended form in gasoline. An experimental research study was carried out to investigate the impacts of low-level MF content in gasoline (volumetric 10% MF in blend) on direct-injection spark-ignition (DISI) engine combustion behavior and emissions. The tests were conducted on a single-cylinder spray-guided DISI research engine at an engine speed of 1500 rpm under stoichiometric conditions. The engine loads of 3.5 ~ 8.5 bar IMEP were tested and gasoline-optimized spark timing was used. Furthermore, the effects of spark timing, exhaust gas recirculation (EGR) and valve overlap on NOx emissions were tested.

Lithium-ion batteries (LiBs) have been widely used in electrified vehicles, and the battery thermal management (BTM) system is needed to maintain the temperature that is critical to battery performance, safety, and health. Conventionally, three-dimensional battery thermal models are developed at the early stage to guide the design of the BTM system, in which battery thermophysical parameters (radial thermal conductivity, axial thermal conductivity, and specific heat capacity) are required. However, in most literature, those parameters were estimated with greatly different values (up to one order of magnitude). In this paper, an investigation is carried out to evaluate the magnitude of the influence of those parameters on the battery simulation results. The study will determine if accurate measurements of battery thermophysical parameters are necessary.