Effects of ambient temperature and cold starts on excess NOx emissions in a gasoline direct injection vehicle

The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct injection (GDI) engine with a displacement of 1.395 L. The test fuels include ethanol-gasoline, n-butanol-gasoline, and DMF-gasoline with four blending ratios of 20%, 50%, 75%, and 100%, and pure gasoline was also tested for comparison. The original contribution of this article is to systemically study the steady-state, transient-state, cold-start, and acceleration performance of the tested fuels under a wide range of blending ratios, especially at high blending ratios. It provides new insight and knowledge of the emission alleviation technique in terms of tailoring the biofuels in GDI turbocharged engines. The results of our works showed that operation with ethanol–gasoline, n-butanol–gasoline, and DMF–gasoline at high blending ratios could be realized in the GDI vehicle without any modification to its engine and the control system at the steady state. At steady-state operation, as compared with pure gasoline, the results indicated that blending n-butanol could reduce CO2, CO, total hydrocarbon (THC), and NOX emissions, which were also decreased by employing a higher blending ratio of n-butanol. However, a high fraction of n-butanol increased the volumetric fuel consumption, and so did the DMF–gasoline and ethanol–gasoline blends. A large fraction of DMF reduced THC emissions, but increased CO2 and NOX emissions. Blending n-butanol can improve the equivalent fuel consumption. Moreover, the particle number (PN) emissions were significantly decreased when using the high blending ratios of the three kinds of oxygenated fuels. According to the results of the New European Drive Cycle (NEDC) cycle, blending 20% of n-butanol with gasoline decreased CO2 emissions by 5.7% compared with pure gasoline and simultaneously reduced CO, THC, NOX emissions, while blending ethanol only reduced NOX emissions. PN and particulate matter (PM) emissions decreased significantly in all stages of the NEDC cycle with the oxygenated fuel blends; the highest reduction ratio in PN was 72.87% upon blending 20% ethanol at the NEDC cycle. The high proportion of n-butanol and DMF improved the acceleration performance of the vehicle.

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Investigation of Injection Strategies to Improve High Efficiency RCCI Combustion With Diesel and Gasoline Direct Injection

ASME 2012 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2012-92107 ◽

2012 ◽

Cited By ~ 17

Author(s):

Martin L. Wissink ◽

Jae H. Lim ◽

Derek A. Splitter ◽

Reed M. Hanson ◽

Rolf D. Reitz

Keyword(s):

High Efficiency ◽

Direct Injection ◽

High Reactivity ◽

Gasoline Direct Injection ◽

Cylinder Wall ◽

Nox Emissions ◽

Heavy Duty ◽

Fuel Vaporization ◽

Heavy Duty Diesel ◽

Injection Strategies

Experiments were performed to investigate injection strategies for improving engine-out emissions of RCCI combustion in a heavy-duty diesel engine. Previous studies of RCCI combustion using port-injected low-reactivity fuel (e.g., gasoline or iso-octane) and direct-injected high-reactivity fuel (e.g., diesel or n-heptane) have reported greater than 56% gross indicated thermal efficiency while meeting the EPA 2010 heavy-duty PM and NOx emissions regulations in-cylinder. However, CO and UHC emissions were higher than in diesel combustion. This increase is thought to be caused by crevice flows of trapped low-reactivity fuel and lower cylinder wall temperatures. In the present study, both the low- and high-reactivity fuels were direct-injected, enabling more precise targeting of the low-reactivity fuel as well as independent stratification of equivalence ratio and reactivity. Experiments with direct-injection of both gasoline and diesel were conducted at 9 bar IMEP and compared to results from experiments with port-injected gasoline and direct-injected diesel at matched conditions. The results indicate that reductions in UHC, CO, and PM are possible with direct-injected gasoline, while maintaining similar gross indicated efficiency as well as NOx emissions well below the EPA 2010 heavy-duty limit. Additionally, experimental results were simulated using multi-dimensional modeling in the KIVA-3V code coupled to a Discrete Multi-Component fuel vaporization model. The simulations suggest that further UHC reductions can be made by using wider injector angles which direct the gasoline spray away from the crevices.

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Time-dependent line-of-sight extinction tomography for multi-hole GDI injectors

International Journal of Spray and Combustion Dynamics ◽

10.1177/1756827716673522 ◽

2016 ◽

Vol 9 (3) ◽

pp. 199-211 ◽

Cited By ~ 3

Author(s):

Yudaya Sivathanu ◽

Jongmook Lim ◽

Varun Kulkarni

Keyword(s):

Ambient Temperature ◽

Direct Injection ◽

Injection Pressure ◽

Gasoline Direct Injection ◽

Time Dependent ◽

Line Of Sight ◽

Experimental Measurements ◽

Fuel Injectors ◽

Factors Affecting ◽

Spray Structure

Finely atomized sprays from multi-hole gasoline direct injection (GDI) fuel injectors make them an ideal choice for automobile applications. A knowledge of the factors affecting the performance of these injectors is hence important. In the study presented here, we employ statistical extinction tomography to examine the transient characteristics of two GDI fuel injectors with five and six holes. Two axial locations, 25 mm and 35 mm from the injector exit, are chosen for experimental measurements, and the dependence of injection pressure and ambient temperature on plume locations and angles is examined from these measurements. A pressure chamber with opposing windows is used which permits the nozzle to be rotated 12 times (30° each rotation) to obtain information on the complete spray structure. Additionally, the plume centroid locations are measured and compared with those obtained with a mechanical patternator. The centroid locations from the two instruments compare favorably.

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SI/HCCI Mode Switching Optimization in a Gasoline Direct Injection Engine Employing Dual Univalve System

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4041516 ◽

2018 ◽

Vol 141 (3) ◽

Cited By ~ 1

Author(s):

Yintong Liu ◽

Liguang Li ◽

Haifeng Lu ◽

Stephan Schmitt ◽

Jun Deng ◽

...

Keyword(s):

High Efficiency ◽

Direct Injection ◽

Load Condition ◽

Gasoline Direct Injection ◽

Mode Switching ◽

Nox Emissions ◽

Combustion Mode ◽

Timing Control ◽

Main Challenge ◽

Low Load

Homogeneous charge compression ignition (HCCI) is a feasible combustion mode meeting future stringent emissions regulations, and has high efficiency and low NOX and particle emissions. As the narrow working condition range is the main challenge limiting the industrialization of HCCI, combustion mode switching between SI and HCCI is necessary when employing HCCI in mass production engines. Based on a modified production gasoline direct injection (GDI) engine equipped with dual UniValve system (a fully continuously variable valvetrain system), SI/HCCI mode switching under low load condition is investigated. According to the results, combustion mode switching from SI to HCCI is more complicated than from HCCI to SI. As HCCI requires strict boundary conditions for reliable and repeatable fuel auto-ignition, abnormal combustion easily appears in transition cycle, especially when combustion switches from SI to HCCI. Timing control strategies can optimize the combustion of transition cycles. With the optimization of timing control, the mode switching from SI to HCCI can be completed with only two transition cycles of late combustion, and abnormal combustion can be avoided during the mode switching from HCCI to SI. Under the low load condition, the indicated efficiency reaches 39% and specific NOX emissions drop down to around 1 mg/L/s when the combustion mode is switched to HCCI mode. Compared to SI mode, the indicated efficiency is increased by 10% and the specific NOX emissions are reduced by around 85%.

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Effect of Extreme Temperatures and Driving Conditions on Gaseous Pollutants of a Euro 6d-Temp Gasoline Vehicle

Atmosphere ◽

10.3390/atmos12081011 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1011

Author(s):

Barouch Giechaskiel ◽

Victor Valverde ◽

Anastasios Kontses ◽

Ricardo Suarez-Bertoa ◽

Tommaso Selleri ◽

...

Keyword(s):

Heavy Traffic ◽

Direct Injection ◽

Urban Environments ◽

Gasoline Direct Injection ◽

Particulate Filter ◽

Gaseous Emissions ◽

Ambient Temperatures ◽

Driving Conditions ◽

On The Road ◽

Cold Starts

Gaseous emissions of modern Euro 6d vehicles, when tested within real driving emissions (RDE) boundaries, are, in most cases, at low levels. There are concerns, though, about their emission performance when tested at or above the boundaries of ambient and driving conditions requirements of RDE regulations. In this study, a Euro 6d-Temp gasoline direct injection (GDI) vehicle with three-way catalyst and gasoline particulate filter was tested on the road and in a laboratory at temperatures ranging between −30 °C and 50 °C, with cycles simulating urban congested traffic, uphill driving while towing a trailer at 85% of the vehicle’s maximum payload, and dynamic driving. The vehicle respected the Euro 6 emission limits, even though they were not applicable to the specific cycles, which were outside of the RDE environmental and trip boundary conditions. Most of the emissions were produced during cold starts and at low ambient temperatures. Heavy traffic, dynamic driving, and high payload were found to increase emissions depending on the pollutant. Even though this car was one of the lowest emitting cars found in the literature, the proposed future Euro 7 limits will require a further decrease in cold start emissions in order to ensure low emission levels under most ambient and driving conditions, particularly in urban environments. Nevertheless, motorway emissions will also have to be controlled well.

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Challenging Conditions for Gasoline Particulate Filters (GPFs)

Catalysts ◽

10.3390/catal12010070 ◽

2022 ◽

Vol 12 (1) ◽

pp. 70

Author(s):

Barouch Giechaskiel ◽

Anastasios Melas ◽

Victor Valverde ◽

Marcos Otura ◽

Giorgio Martini

Keyword(s):

Ambient Temperature ◽

Direct Injection ◽

Number System ◽

Gasoline Direct Injection ◽

Oxidation Catalyst ◽

Particulate Emissions ◽

High Concentration ◽

Rear Window ◽

Particulate Filters ◽

Low Efficiency

The emission limit of non-volatile particles (i.e., particles that do not evaporate at 350 °C) with size >23 nm, in combination with the real driving emissions (RDE) regulation in 2017, resulted in the introduction of gasoline particulate filters (GPFs) in all light-duty vehicles with gasoline direct injection engines in Europe. Even though there are studies that have examined the particulate emissions at or beyond the current RDE boundary conditions, there is a lack of studies combining most or all worst cases (i.e., conditions that increase the emissions). In this study, we challenged a fresh (i.e., no accumulation of soot or ash) “advanced” prototype GPF at different temperatures (down to −9 °C), aggressive drive cycles and hard accelerations (beyond the RDE limits), high payload (up to 90%), use of all auxiliaries (air conditioning, heating of the seats and the rear window), and cold starts independently or simultaneously. Under hot engine conditions, the increase of the particulate emissions due to higher payload and lower ambient temperature was 30–90%. The cold start at low ambient temperature, however, had an effect on the emissions of up to a factor of 20 for particles >23 nm or 300 when considering particles <23 nm. We proposed that the reason for these high emissions was the incomplete combustion and the low efficiency of the three-way oxidation catalyst. This resulted in a high concentration of species that were in the gaseous phase at the high temperature of the close-coupled GPF and thus could not be filtered by the GPF. As the exhaust gas cooled down, these precursor species formed particles that could not be evaporated at 350 °C (the temperature of the particle number system). These results highlight the importance of the proper calibration of the engine out emissions at all conditions, even when a GPF is installed.

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Laboratory and On-Road Evaluation of a GPF-Equipped Gasoline Vehicle

Catalysts ◽

10.3390/catal9080678 ◽

2019 ◽

Vol 9 (8) ◽

pp. 678 ◽

Cited By ~ 5

Author(s):

Ricardo Suarez-Bertoa ◽

Tero Lähde ◽

Jelica Pavlovic ◽

Victor Valverde ◽

Michael Clairotte ◽

...

Keyword(s):

Laboratory Test ◽

Mass Production ◽

Particle Number ◽

Direct Injection ◽

Gasoline Direct Injection ◽

Nox Emissions ◽

Ambient Temperatures ◽

Particulate Filters ◽

Gdi Engines ◽

Total Hydrocarbons

The introduction of a solid particle number limit for vehicles with gasoline direct injection (GDI) engines resulted in a lot of research and improvements in this field in the last decade. The requirement to also fulfil the limit in the recently introduced real-driving emissions (RDE) regulation led to the introduction of gasoline particulate filters (GPFs) in European vehicle models. As the pre-standardisation research was based on engines, retrofitted vehicles and prototype vehicles, there is a need to better characterise the actual emissions of GPF-equipped GDI vehicles. In the present study we investigate one of the first mass production vehicles with GPF available in the European market. Regulated and non-regulated pollutants were measured over different test cycles and ambient temperatures (23 °C and −7 °C) in the laboratory and different on-road routes driven normally or dynamically and up to 1100 m altitude. The results showed that the vehicle respected all applicable limits. However, under certain conditions high emissions of some pollutants were measured (total hydrocarbons emissions at −7 °C, high CO during dynamic RDE tests and high NOx emissions in one dynamic RDE test). The particle number emissions, even including those below 23 nm, were lower than 6 × 1010 particles/km under all laboratory test cycles and on-road routes, which are <10% of the current laboratory limit (6 × 1011 particles/km).

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Particle Number Emissions of Gasoline, Compressed Natural Gas (CNG) and Liquefied Petroleum Gas (LPG) Fueled Vehicles at Different Ambient Temperatures

Atmosphere ◽

10.3390/atmos12070893 ◽

2021 ◽

Vol 12 (7) ◽

pp. 893

Author(s):

Tero Lähde ◽

Barouch Giechaskiel

Keyword(s):

Natural Gas ◽

Ambient Temperature ◽

Solid Particle ◽

Fossil Fuels ◽

Particle Number ◽

Direct Injection ◽

Gasoline Direct Injection ◽

Liquefied Petroleum Gas ◽

Compressed Natural Gas ◽

Ambient Temperatures

Compressed natural gas (CNG) and liquefied petroleum gas (LPG) are included in the group of promoted transport fuel alternatives for traditional fossil fuels in Europe. Both CNG and LPG fueled vehicles are believed to have low particle number and mass emissions. Here, we studied the solid particle number (SPN) emissions >4 nm, >10 nm and >23 nm of bi-fuel vehicles applying CNG, LPG and gasoline fuels in laboratory at 23 °C and sub-zero (−7 °C) ambient temperature conditions. The SPN23 emissions in CNG or LPG operation modality at 23 °C were below the regulated SPN23 limit of diesel and gasoline direct injection vehicles 1/km. Nevertheless, the limit was exceeded at sub-zero temperatures, when sub-23 nm particles were included, or when gasoline was used as a fuel. The key message of this study is that gas-fueled vehicles produced particles mainly <23 nm and the current methodology might not be appropriate. However, only in a few cases absolute SPN >10 nm emission levels exceeded 6 ×1011 1/km when >23 nm levels were below 6 ×1011 1/km. Setting a limit of 1 ×1011 1/km for >10 nm particles would also limit most of the >4 nm SPN levels below 6 ×1011 1/km.

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3-Cylinder Turbocharged Gasoline Direct Injection: A High Value Solution for Low CO2 and NOx Emissions

SAE International Journal of Engines ◽

10.4271/2010-01-0590 ◽

2010 ◽

Vol 3 (1) ◽

pp. 355-371 ◽

Cited By ~ 34

Author(s):

John E. Kirwan ◽

Mark Shost ◽

Gregory Roth ◽

James Zizelman

Keyword(s):

Direct Injection ◽

Gasoline Direct Injection ◽

Nox Emissions ◽

Low Co2

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Investigations of split injection properties on the spray characteristics using a solenoid high-pressure injector

International Journal of Engine Research ◽

10.1177/1468087420985372 ◽

2021 ◽

pp. 146808742098537

Author(s):

Meghnaa Dhanji ◽

Hua Zhao

Keyword(s):

High Pressure ◽

Direct Injection ◽

Gasoline Direct Injection ◽

Diffusion Combustion ◽

Split Injection ◽

Spray Characteristics ◽

Injection Strategy ◽

Cold Starts ◽

Opening And Closing ◽

Gdi Engines

An on-going challenge with Gasoline direct injection (GDI) engines is achieving rapid activation of the exhaust catalyst during cold starts, in order to reduce the Nitrogen Oxide (NOx) emissions. Injecting late in the compression stroke, in the efforts to form a stratified mixture, provides the fuel insufficient time to be entrained with the surrounding charge. This results in locally fuel rich diffusion combustion and the formation of high levels of particulate matter. Employing a split injection strategy can help tackle these issues. The current study examines the effects of a split injection strategy on the spray characteristics. Varying pulse width (PW) combinations, split ratios and dwell times are investigated using a Solenoid actuated high pressure injector. The injected quantity and the droplet characteristics of a target plume are investigated. The experiments were performed in a constant volume spray chamber. The droplet velocities and sizes were measured using Phase Doppler Particle Anemometry (PDA). Short and large PWs, in the range of 0.3–0.8 ms, were investigated. The results revealed that the highest injected quantity of fuel was measured with the shortest dwell time of 2 ms, owing to increased interactions between the injection events, which led to larger Sauter mean diameters (SMDs) measured. The SMDs for the shorter PW of 0.4 ms were generally larger than 0.8 ms PW. The droplets in this case were affected by the closely spaced opening and closing events of the Solenoid valve.

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