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Catalyzed gasoline particulate filters (cGPF) are one of the most effective emission control technologies for reducing gaseous and particulate emissions simultaneously. Successful adoption of this advanced technology relies on several important performance properties including low back pressure, high filtration efficiency and specially durability compliance. In this work using an underfloor cGPF, the backpressure control was achieved through optimizing catalyst coating technology and modifying the deposition profile of catalyst coating along GPF channels. Durability performance was demonstrated by using an accelerated engine aging method with selective blending of lubricating oils in fuel, which incorporates the aging mechanisms of thermal aging, ash loading, and soot accumulation/regeneration. The target durability demonstration represents 200,000 km real world operation.

Catalyzed gasoline particulate filter (cGPF) is the prime technology to meet future stringent regulations for particulates from gasoline direct injection (GDI) engines. One of the technical concerns is the ultimate durability of cGPF in regards to engine lubricant formulations. This study investigated two tailored lubricant formulations on catalyzed GPFs which were aged on engine followed by emission testing on vehicle. An engine accelerated aging protocol was developed for cGPFs to simulate thermal aging, ash and soot loading that is at least equivalent to 200,000 km durability requirement. Evaluations include tailpipe emission levels, backpressure, catalytic performance, and post-mortem analysis. Both formulations have demonstrated a high level of cGPF performance retention; performance being assessed in terms of emission level at the end of durability demonstration testing. These formulations provide flexibility in selecting robust lubricant to meet various system requirements.

Gasoline particulate filter (GPF) is considered a suitable solution to meet the increasingly stringent particle number (PN) regulations for both gasoline direct injection (GDI) and multi-port fuel injection (MPI) engines. Generally, GDI engines emit more particulate matter (PM) and PN. In recent years, GDI engines have gained significant market penetration in the automobile industry owing to better fuel economy and drivability. In this study, an accelerated ash loading method was tested by doping lubricating oil into the fuel for a GDI engine. Emission tests were performed at different ash loads with different driving cycles and GPF combinations. The results showed that the GPF could significantly reduce particle emissions to meet the China 6 regulation. With further ash loading, the filtration efficiency increased above 99% and the effects on fuel consumption and backpressure were found to be limited, even with an ash loading of up to 50 g/l.

Because of the increased use of gasoline direct engine (GDI) in the automobile industry, there is a significant need to control particulates from GDI engines based on emission regulations. One potential technical approach is the utilization of a gasoline particulate filter (GPF). The successful adoption of this emission control technology needs to take many aspects into consideration and requires a system approach for optimization. This study conducted research to investigate the impact of vehicle driving cycles, fuel properties and catalyst coating on the performance of GPF. It was found that driving cycle has significant impact on particulate emission. Fuel quality still plays a role in particulate emissions, and can affect the GPF performance. Catalyzed GPF is preferred for soot regeneration, especially for the case that the vehicle operation is dominated by congested city driving condition, i.e. low operating temperatures. The details of the study are presented in the paper.

In this paper, the impacts of Aromatic and Olefin on the formation of poly-aromatic hydrocarbons (PAHs) in the gasoline direct injection (GDI) engine were experimentally and numerically investigated. The objective of this study is to describe the formation process of the soot precursors including one ring to four ring aromatics (A1-A4). In order to better understand the effects of the fuel properties on the formations of PAHs. Three types of fuels, namely base gasoline, gasoline with higher aromatics content, and gasoline with higher olefin content were experimentally studied. At the same time, these aspects were also numerically investigated in the CHEMKIN code by using premixed laminar flame model and surrogated fuels. The results show that higher aromatics content in gasoline will lead to much higher PAHs formation. Similar trend was also found in the gasoline with higher olefin content.

A conceptual approach to help understand and simulate droplet induced pre-ignition is presented. The complex phenomenon of oil-fuel droplet induced pre-ignition has been decomposed to its elementary processes. This approach helps identify the key fluid properties and engine parameters that affect the pre-ignition phenomenon, and could be used to control LSPI. Based on the conceptual model, a 3D CFD engine simulation has been developed which is able to realistically model all of the elementary processes involved in droplet induced pre-ignition. The simulation was successfully able to predict droplet induced pre-ignition at conditions where the phenomenon has been experimentally observed. The simulation has been able to help explain the observation of pre-ignition advancement relative to injection timing as experimentally observed in a previous study [6].

Gasoline Direct Injection (GDI) engines have developed rapidly in recent years driven by fuel efficiency and consumption requirements, but face challenges such as injector deposits and particulate emissions compared to Port Fuel Injection (PFI) engines. While the mechanisms of GDI injector deposits formation and that of particulate emissions have been respectively revealed well, the impact of GDI injector deposits and their relation to particulate emissions have not yet been understood very well through systematic approach to investigate vehicle emissions together with injector spray analysis. In this paper, an experimental study was conducted on a GDI vehicle produced by a Chinese Original Equipment Manufacturer (OEM) and an optical spray test bench to determine the impact of injector deposits on spray and particulate emissions.

High boost and direct injection are effective ways for energy saving in gasoline engines. However, the occurrence of super-knock at high load has become a main obstacle for further improving power density and fuel economy. It has been known that super-knock can be induced by pre-ignition, and oil droplet auto-ignition is found to be one of the possible mechanisms. In this study, experiments were conducted in a single-cylinder thermal research engine (TRE), in which different types of oil and surrogates were directly injected into the cylinder and then led to pre-ignition and super-knock. The effect of oil injection timing, oil injection quantity, different gasoline and different oil were tested. All the oil in this work could induce pre-ignition, even though their combustion phasing was much later than that in the case of n-hexadecane.

An experimental study of particulate matter (PM) emission was conducted on four cars from Chinese market. Three cars were powered by gasoline direct injection (GDI) engines and one car was powered by a port fuel injection (PFI) engine. Particulate mass, number and size distribution were measured based on a chassis dynamometer over new European driving cycle (NEDC). The particulate emission behaviors during cold start and hot start NEDCs were compared to understand how the running conditions influence particulate emission. Three kinds of gasoline with RON 91.9, 94.0 and 97.4 were tested to find the impact of RON on particulate emission. Because of time and facilities constraints, only one cold/hot start NEDC was conducted for every vehicle fueled with every fuel. The test results showed that more particles were emitted during cold start condition (first 200s in NEDC). Compared with cold start NEDC, the particulate mass and number of hot start NEDC decreased by a wide margin.