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The Real Driving Emissions (RDE) test method has been introduced after 2017 to regulate the vehicle emissions in real-world driving situations by means of on-board emissions measurements. This paper aims to estimate the detailed on-board gaseous emissions from a light-duty direct-injection gasoline vehicle simultaneously using both portable emissions measurement system (PEMS) and sensor-based emissions measurement system (SEMS). Test route is typical urban route and tests environment factors followed the RDE regulation. Carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and ammonia (NH3) emissions were analyzed according to cold start once and followed by hot start conditions. The mass emissions of gas components were calculated based on the exhaust flowrate obtained from OBD parameters, NH3 emission was calculated based on NO sensor’s data. Two drivers participated in the tests and their emissions difference has been compared.

In recent years, particulate matter (PM) emitted from direct-injection gasoline vehicles is becoming an increasingly concerning problem. In addition, it is often reported that ammonia (NH3) is emitted from gasoline vehicles equipped with a three-way catalyst. These emissions might be largely emitted especially when driving in on-road driving conditions. In this study, we investigated the emissions, NOx, NH3, and PM/PN (particulate number) of a light-duty direct-injection gasoline vehicle when driving on actual roads. Using a small direct-injection gasoline vehicle equipped with a three-way catalyst, experiment was conducted 8 times on the same route, and these emissions were measured. In this study, vehicle specific power (VSP) was introduced, which can be calculated using vehicle parameters, vehicle speed, and road gradient. The effects of parameters acquired through on-board diagnostics (OBD) port and VSP on emissions were investigated.

Every year, exhaust gas regulations are getting stricter with the intention to solve the average air pollution problem, however, local roadside pollution is still a pressing issue. In order to solve this local roadside pollution problem, it is necessary to evaluate and/or predict “where” and “how much” pollutants such as NOx are emitted. To predict the local roadside pollution, it is necessary to collect emissions data from various kinds of vehicles driving on real-world and analyze them. In recent years, Real Driving Emission regulations using PEMS (Portable Emission Measurement System) have been introduced mainly in Europe. A typical PEMS configuration can weigh close to 100 kg however, and its weight affects the driving conditions of vehicles running on actual roads. In this study, we focused on the analysis of real-world emissions using SEMS (Sensor-based Emission Measurement System).

A simultaneous multi-composition analyzing (SMCA) resonance enhanced multi-photon ionization (REMPI) system was used to investigate gasoline engine exhaust. Observed peaks for exhaust were smaller mass numbers than those from diesel exhaust. However, large species up to three ring aromatics were observed suggesting that soot precursor forms even in the gasoline engine. At low catalyst temperature condition, the reduction efficiencies of a three-way catalyst were higher for higher mass numbers. This result indicates that the larger species accumulate in the catalyst or elsewhere due to their lower vapor pressures. To evaluate the emission of low volatility species, the accumulation should be taken into account. In the hot mode, reduction efficiencies for aromatic species of three-way catalyst were almost 99.5% however, they fall to 70% in the cold start condition.