On-board diagnosis of engine and transmission systems has been mandated by government regulation for light and medium vehicles since the 1996 model year. The regulations specify many of the detailed features that on-board diagnostics must exhibit. In addition, the penalties for not meeting the requirements or providing in-field remedies can be very expensive. This course is designed to provide a fundamental understanding of how and why OBD systems function and the technical features that a diagnostic should have in order to ensure compliant and successful implementation.
This course is designed to provide an overview of the fundamental design objectives and the features needed to achieve those objectives for generic on-board diagnostics. The basic structure of an on-board diagnostic will be described along with the system definitions needed for successful implementation.
To satisfy recent stringent exhaust gas regulations, large amounts of Rh and Pd have been often employed in three-way catalysts (TWCs) as main active components. However, application of Pt-based TWCs are limited due to their lower thermal stability than Pd. Previously, we found that Pt-based TWCs with a small amount of CeO2 showed high catalytic performance in gasoline vehicles test. Especially, calcined CeO2 at high temperature before Pt loading (cal-CeO2) showed higher catalytic activity than untreated CeO2 after endurance at 1000 degree centigrade. This result could be attributed to higher redox performance and Pt dispersion derived from strong interaction between Ce and Pt. Even though cal-CeO2 has low specific surface area (SSA) given by preliminary calcination, it shows strong effects on catalytic performance. In other word, improvement of its SSA could be the most powerful way to prepare highly active Pt catalysts.
SAE J1979 and its “OBD Modes” served the protection of our environment against harmful pollutants for decades, but due to regulatory adoption of OBDonUDS, SAE J1979 now becomes a multiple part document series. SAE J1979 will be replaced by SAE J1979-2 for vehicles with combustion engines and by SAE J1979-3 for Zero Emission Vehicle (ZEV) Propulsion systems. For ZEV, emission-related failures will be replaced by ZEV propulsion related failures. Both SAE J1979-2 and -3 are variants of ISO 14229 (UDS) but limited to OBD-related failures, meaning that these new diagnostic communication protocols are required by law but do not support advanced diagnostic functions, such as flash programming. For performance reasons of the flash process, the deployment of UDSonIP as it is standardized in ISO 14229-5 became state-of-the art.
The gasoline particulate filter (GPF) represents a practical solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as an essential technology in North America to meet the upcoming US EPA tailpipe emission regulation, as proposed in the “Multi-pollutant Rule for Model Year 2027”. The goal of this study was to introduce advanced, uncoated GPF products and measure their particulate mass (PM) reduction performance within the existing US EPA FTP vehicle testing procedures, as detailed in Code of Federal Regulations (CFR) part 1066. Various state-of-the-art GPF products were characterized for their microstructure properties and lab-bench performance for pressure drop and filtration efficiency, were then subjected to an EPA-recommended 2000mile on-road break-in, and finally were tested on an AWD vehicle chassis-dyno emissions test cell at both 25C and -7C ambient conditions.
The impending emission regulations in both China (CN7) and the United States (Tier 4) are set to impose more stringent emission limits on hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). CN7 places particular emphasis on reducing particulate number (PN) thresholds, while the forthcoming United States Tier 4 legislation is primarily concerned with reducing the allowable particulate matter (PM) to an assumed limit of 0.5 mg/mile. Given the more stringent constraints on both PN and PM emissions, the development of enhanced aftertreatment solutions becomes imperative to comply with these new regulatory demands. Coated Gasoline Particulate Filters (cGPF) play a pivotal role as essential components for effective PN and PM abatement.
Options for CNVII emission legislation are being widely investigated in a national program organized by China Vehicle Emission Control Center (VECC) since early 2020. It is foreseen that this possibly last legislation in China will have more stringent emission requirements compared to CNVI, including further reduction of nitrogen oxide (NOx), inclusion of nitrous oxide (N2O) and sub-23 nm particle number (PN) and etc. This study investigates the technical feasibility to fulfill a CNVII emission legislation scenario, based on a modified CNVI 8 L engine operating under both cold and hot World Harmonized Transient Cycle (WHTC) and Low Load Cycle (LLC). Methods to address the challenges are discussed and validated, including a twin dosing system, electric heater, hybrid concept of combining Copper (Cu-), Iron (Fe-) and Vanadium (V-) SCR technologies, high filtration DPF and optimization of engine calibration and urea dosing strategies.
Exhaust gas recirculation technology is one of the main methods to reduce engine emissions. The pressure of the intake pipe of supercharged direct-injection diesel engine is high, and it is difficult to realize EGR technology. The application of Venturi tube can easily solve this problem. In this paper, the working principle of guide-injection Venturi tube is introduced, the EGR system and structure of a turbocharged diesel engine using the guide-injection Venturi tube are studied. According to the working principle of EGR system of turbocharged diesel engine, the model of guide-injection Venturi tube is established, the calculation grid is divided, and it is carried out by using Computational Fluid Dynamics method that the three-dimensional numerical simulation of the internal flow of Venturi tube under different EGR rates injection.
With the increasing number of hybrid vehicles in the Chinese market, research on aftertreatment system for hybrid vehicles has become very popular. China has currently issued national China6 regulations and also regulated the emissions of hybrid vehicles. So far, there are few reports on the optimization of aftertreatment for hybrid gasoline vehicles. Due to the involvement of electric motors in hybrid vehicles, the engine frequently starts lead to inconsistent stability of engine operating conditions and also bring the challenge to emission control of engine exhaust emissions. This article mainly selects a highly popular hybrid vehicle in China for research, which is a dual model hybrid (DM-hybrid) passenger car. There is a significant correlation between the emissions during the journey of driving and the hybrid strategy.
The target of the newly and future automotive emission regulations is to promote a fast transition to near-zero emission vehicles. As such, the range of ambient and operating conditions tested in the homologation cycles is broadening. In this context, the proposed work aims to thoroughly investigate the potential of post-oxidation phenomena in reducing the light-off time of a conventional three-way catalyst. The study is carried out on a turbocharged four-cylinder gasoline engine by means of experimental and numerical activities. Post oxidation is achieved through the oxidation of unburned fuel in the exhaust line, exploiting a rich combustion and a secondary air injection dedicated strategy. The CFD methodology consists of two different approaches: the former relying on a full-engine mesh, the latter on a detailed analysis of the chemical reactions occurring in the exhaust line.
Stoichiometric natural gas (CNG) engines are an attractive solution for heavy-duty vehicles considering their inherent advantage in emitting lower CO2 emissions compared to their Diesel counterparts. Additionally, their aftertreatment system can be simpler and less costly as NOx reduction is handled simultaneously with CO/HC oxidation by a Three-Way Catalyst (TWC). The conversion of methane over a TWC shows a complex behavior, significantly different than non-methane hydrocarbons in stoichiometric gasoline engines. Its performance is maximized in a narrow A/F window and is strongly affected by the lean/rich cycling frequency. It is believed that lean-mode efficiency is governed by the palladium’s oxidation state while rich conversion is governed by the gradual formation of carbonaceous compounds which temporarily deactivate the active materials.