Perovskite Catalyst for In-Cylinder Coating to Reduce Raw Pollutant Emissions of Internal Combustion Engines

Abstract

Aiming to achieve the highest combustion efficiency and less pollutant emission, a catalytic coating for cylinder walls in internal combustion engines was developed and tested under several conditions. The coating consists of a La0.8Sr0.2CoO3 (LSCO) catalyst on an aluminum-based ceramic support. Atomic force microscopy was applied to investigate the surface roughness of the LSCO coating, while in situ diffuse infrared Fourier transform spectroscopy was used to obtain the molecular understanding of adsorption and conversion. In addition, the influence of LSCO-coated substrates on the flame quenching distance was studied in a constant-volume combustion chamber. Investigations conclude that an LSCO coating leads to a reduction of flame quenching at low wall temperatures but a negligible effect at high temperatures. Finally, the influence of LSCO coatings on the in-cylinder wall-near gas composition was investigated using a fast gas sampling methodology with sample durations below 1 ms. Ion molecule reaction mass spectrometry and Fourier transform infrared spectroscopy revealed a significant reduction of hydrocarbons and carbon monoxide when LSCO coating was applied.

Influence of Yttria-Stabilized Zirconium Oxide Thermal Swing Coating on the Flame-Wall Interaction in Spark Ignition Engines

“…Aluminum oxide chips equipped with a backside resistive heating circuit (99.6% aluminum oxide, University Bayreuth, Bayreuth, Germany) were used as substrates to deposit the YSZ, which have been reported in our previous work [24,25]. The coated ceramic substrate was placed inside a high-temperature reaction chamber (HVC−DRP, Harrick Scientific Products, Inc., Pleasantville, NY, USA) for in-situ DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) measurements.…”

“…Quenching distance measurements have been performed in a cylindrical constant volume combustion chamber (CVCC) with a volume of 500 mL that has been used for similar studies before [25]. The setup is based on the work of Bellenoue et al [26].…”

“…The experimental procedure for the highresolution single-shot images is described in detail below. It is similar to the procedure that was applied in our previous work [25]. Each experiment consisted of three steps: (a) the recording of reference images for the determination of the object position, (b) the recording of the flame-wall interaction for the flame position determination, and (c) the post-processing to calculate the quenching distance (Figure 4).…”

“…To estimate the impact of this coating at engine-relevant conditions, a constant Péclet number over pressure [25] was assumed for the case of 20 bar and 200 • C. This would lead to a quenching distance of 34 µm for the uncoated wall and to 32 µm for the YSZ-coated wall. The achieved reduction would only be 2 µm (−5.6%), which takes into account only the reduction by the changed thermal properties for the same wall temperature.…”

“…Energies 2023, 15, x FOR PEER REVIEW To estimate the impact of this coating at engine-relevant conditions, a co number over pressure [25] was assumed for the case of 20 bar and 200 °C. Thi to a quenching distance of 34 μm for the uncoated wall and to 32 μm for the wall.…”