Refine Your Search

Topic

Author

Affiliation

Search Results

Training / Education

Emissions-Related OBD Systems A Design Overview

2019-09-20
On-board diagnostics, required by governmental regulations, provide a means for reducing harmful pollutants into the environment. Since being mandated in 1996, the regulations have continued to evolve and require engineers to design systems that meet strict guidelines. This one day seminar 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.
Technical Paper

A Review of Spark-Assisted Compression Ignition (SACI) Research in the Context of Realizing a Production SACI Strategy

2019-08-15
2019-24-0027
Low temperature combustion (LTC) strategies have been a keen interest in the automotive industry for over four decades since they offer improved fuel efficiency compared to conventional spark-ignition (SI) engines. LTC strategies use high dilution to keep combustion temperatures below about 2000 K to reduce heat transfer losses while avoiding locally rich in-cylinder regions that produce high soot. High dilution also enables an efficiency improvement from reduced pumping work and improved thermodynamic properties, though it requires high ignition energy. Combustion can be achieved by triggering autoignition from compression energy. High compression ratios are typically required to produce this level of ignition energy, which further improves fuel efficiency. The timing of the autoignition event is influenced by fuel properties and mixture composition, and is exponentially sensitive to temperature.
Technical Paper

Impact of cooled EGR on performance and emissions of a turbocharged Spark-Ignition engine under low-full load conditions

2019-08-15
2019-24-0021
The stringent worldwide exhaust emission legislations for CO2 and pollutants require significant efforts to increase both the combustion efficiency and the emission quality of internal combustion engines. With this aim, several solutions are continuously produced to improve the combustion efficiency of spark ignition engines. Among the various solutions, EGR represents a well-established technology to improve the gasoline engine performance and the nitrogen-oxides emissions. This work presents the results of an experimental investigation on the effects of the EGR technique on combustion evolution, knock tendency, performance and emissions of a small–size turbocharged PFI SI engine, equipped with an external cooled EGR system. Measurements are carried out at different engine speeds, on a wide range of loads and EGR levels. The standard engine calibration is applied at the reference test conditions.
Technical Paper

Evaluation of water and EGR effects on combustion characteristics of GDI engines using a chemical kinetics approach

2019-08-15
2019-24-0019
The modern spark ignition engines, due to the introduced strategies for limiting the consumption without reducing the power, are sensitive to both the detonation and the increase of the inlet turbine temperature. In order to reduce the risk of detonation, the use of dilution with the products of combustion (EGR) is an established practice that has recently was improved with the use of water vapour obtained via direct or indirect injection. The application and optimization of these strategies cannot ignore the knowledge of physical quantities characterizing the combustion such as the laminar flame speed and the ignition delay, both are an intrinsic property of the fuel and are function of the mixture composition (mixture fraction and dilution) and of its thermodynamic conditions. The experimental measurements of the laminar flame speed and the ignition delay available in literature, rarely report the effects of dilution by EGR or water vapor.
Technical Paper

Learning based MPC control of combustion timing in Multi-Cylinder Partially Premixed Combustion Engine

2019-08-15
2019-24-0016
Partially Premixed Combustion has shown to be a promising advanced combustion mode for future engines in terms of efficiency and emission levels. The combustion timing should be suitably phased to realize high efficiency. However, a simple map-based feed-forward control method is not sufficient for controlling the combustion during transient operation. This article proposes one learning-based model predictive control (MPC) approach to achieve controllability and feasibility. Since PPC engines could have unacceptably high pressure-rise rates at different operation points, triple injection is applied as a solvent, with the use of two pilot fuel injection. The controller utilizes the main injection timing to manage the combustion timing, and the first and second injection timing is considered as a function of the engine load and speed. The cylinder pressure is used as the combustion feedback.
Technical Paper

Development of Three Way Catalyst (TWC) ageing model: application of real driving emission condidion

2019-08-15
2019-24-0047
Further reduction of vehicles pollutant and CO2 emissions is required to prevent global warming and to improve air quality. The exhaust system is designed to ensure low emission during all life of the vehicle. As catalyst ageing is affecting the catalyst performance, such impact needs to be consider upfront during the design of the fresh catalyst. Until now, exhaust system design are evaluated based on real tests for each vehicle, using exhaust lines aged on engine test benches or burner benches. This induces major investigation limitations such as: late evaluation in development cycle, high testing and prototyping cost. Usage of Model Based Development approach can be a powerful way to improve this process by allowing system evaluation under several ageing conditions at early development stage. The present study focuses on modelling of Three Way Catalyst (TWC) ageing to predict the mileage impact on tailpipe emissions.
Technical Paper

Selection of Three Way Catalyst Converter for CNG engine to meet BSVI Emission Norms

2019-08-15
2019-24-0044
Compressed natural gas (CNG) is a substitution of alternative fuel for automotive application with significant environmental advantages as it is the only fuel cheaper than gasoline or diesel, comparatively lower air pollution emissions, lesser CO2 emissions. Stringent regulations have been adopted to curb the menace of vehicular pollution. In order to meet the stringent regulations catalytic convertor using noble metals proved to a boon in vehicular industry. Noble metals are highly active for removal of methane as a pollutant. However, their expensiveness, deterioration with time can generate even more toxic volatile pollutants. The paper related to developing of a new gas engines with high energy efficiency and meeting future emission standards. It is necessary to develop complex exhaust gas after treatment systems to treat the toxic components efficiently when the engine runs on stoichiometric and lean mixtures.
Technical Paper

One-Dimensional Modeling of a Thermochemical Recuperation Scheme for Improving Spark-Ignition Range Extender Engine Efficiency

2019-08-15
2019-24-0066
Vehicle electrification has accelerated as global fuel efficiency standards have become more stringent and battery costs have decreased. Although full electrification, i.e.; battery electric vehicles, may be appropriate for some light-duty vehicle applications, many vehicles will still require an engine to overcome range limitations. Range extender (REx) engine generators can be used to charge vehicle batteries as needed to meet driver demands. One advantage of REx engines is that they do not have a direct mechanical connection to the wheels and can frequently within the most efficient speed and load ranges. Therefore, REx engines provide an opportunity to implement advanced engine technologies that are more difficult to apply in conventional engine-powered vehicles. Thermochemical recuperation (TCR) schemes use exhaust waste heat to catalytically convert a portion of the fuel into a gas that has increased heating value.
Technical Paper

Development of a dedicated CNG three-way catalyst model in 1-D simulation platforms

2019-08-15
2019-24-0074
A growing interest in heavy-duty engines powered with CNG dictated by stringent regulations in terms of emissions, has made it essential to study a specific Three-Way Catalyst (TWC). Oxygen storage phenomena characterize catalytic converter efficiency under real world driving operating conditions and, consequently, during strong dynamics in Air-to-Fuel (A/F) ratio. A numerical “quasi-steady” model has been set-up to simulate the chemical process inside the reactor. A dedicated experimental campaign has been performed in order to evaluate the catalyst response to a defined lambda variation pattern of the engine exhaust stream, thus providing the data necessary for the numerical model validation. In fact, goal of the present research activity was to investigate the effect of very fast composition transitions of the engine exhaust typical of the mentioned driving conditions (including fuel cutoffs etc.) on the catalyst performance and on related emissions at the tailpipe.
Technical Paper

A new take on porous medium approach for modelling monoliths and other multiple channel devices

2019-08-15
2019-24-0049
Porous medium approach is widely used in modelling high resistance devices such as heat exchangers, automotive catalysts or filters, where details of flow distribution inside the channels are not important. This reduces the computational time considerably, as the whole length of the monolith does not need to be modelled, and the thin boundary layers in each channel do not need to be resolved. The drawback of the approach is compromised accuracy of the flow predictions downstream of the monolith, because the mixing of the individual jets coming out of the monolith channels is not accounted for. Very few studies exist where this issue has been addressed. The methods include artificial turbulence generation, inferring turbulence information from upstream, or using hybrid modelling approach to separate the flow into channels.
Technical Paper

Potential of 1D Thermo-Fluid Dynamic Modeling in Reducing the Experimental Effort through the comparison of the achievable calibration performance

2019-08-15
2019-24-0013
Over the last decades, internal combustion engines have undergone a continuous evolution to achieve better performance, lower pollutant emissions and fuel consumption. This evolution involved changes in the engine architecture needed to perform advanced management strategies. Therefore, Variable Valve Actuation, Exhaust Gas Recirculation, Gasoline Direct Injection, turbocharging and powertrain hybridization have wide application in the automotive field. However, the effective management of a such complex system is due to the contemporaneous development of the on-board engine electronic control unit (EECU). In fact, the additional degrees of freedom available for the engine regulation highly increased the complexity of engine control and management, resulting in a very expensive and long calibration process. To overcome the drawbacks related to extensive calibration process, this study proposes an effective methodology based on the adoption of 1D thermo-fluid dynamic modelling.
Technical Paper

Sensitivity Analysis of the Combustion Parameters in a Stratified HCCI Engine with Regard to Performance and Emission

2019-08-15
2019-24-0114
Homogeneous charge compression ignition (HCCI) is a promised solution to environmental and fuel economy concerns for IC engines. Engine application for HCCI engine depends on an array of parameters such as fuel type, mixture composition, intake condition and engine specification, meaning that controlling an HCCI engine can only be done through the adjustment of these parameters. In this numerical study which is driven from an experimental work, thermal and charge stratification is used to control HCCI combustion. The effect of intake temperature, compression ratio, intake pressure, EGR, reformer gas (CO-H2 mixture) and glow plug temperature on engine performance and emission was investigated using a 3D model on AVL-FIRE parallel with 1D model on GT-Power software. Then AHP model as a multiple Attribute Decision making method has been used to analyze the sensitivity of these parameters on performance and emission.
Technical Paper

The effect of post injection coupled with extremely high injection pressure on combustion process and emission formation in an off-road diesel engine: a numerical and experimental investigation.

2019-08-15
2019-24-0092
In this paper, a numerical and experimental assessment of post injection potential for soot emissions mitigation in an off-road diesel engine is presented, with the aim of supporting hardware selection and engine calibration processes. As a case study, a prototype off-road 3.4 liters 4-cylinder diesel engine developed by Kohler Engines was selected. In order to comply with Stage V emission standards without a dedicated aftertreatment for NOx, the engine was equipped with a low pressure cooled EGR, allowing high EGR rates (above 30%) even at high load. To enable the exploitation of such high EGR rates with acceptable soot penalties, a two stage turbocharger and an extremely high pressure fuel injection system (up to 3000 bar) were adopted. Moreover, post injections events were also exploited to further mitigate soot emissions with acceptable Brake Specific Fuel Consumption (BSFC) penalties.
Technical Paper

Analysis of Water Injection Strategies to Exploit the Thermodynamic Effects of Water in Gasoline Engines by Means of 3D-CFD Simulations

2019-08-15
2019-24-0102
CO2 emission constraints taking effect from 2020 lead to further investigate technologies to lower knock sensitivity of gasoline engines, main limiting factor to increase engine efficiency and thus reduce fuel consumption. Moreover the RDE cycle demands for higher power operation, where fuel enrichment is needed for component protection. To achieve high efficiency, the engine should be run at stoichiometric conditions in order to have better emission control and reduce fuel consumption. Among others, water injection is a promising technology to improve engine combustion efficiency and to keep high conversion rates of the TWC over the whole engine map. The comprehension of multiple thermodynamic effects of water injection through 3D-CFD simulations and their exploitation to enhance the engine combustion efficiency is the main purpose of the analysis.
Technical Paper

Influence of Injection Strategies on Engine Efficiency for a Methanol PPC Engine

2019-08-15
2019-24-0116
Partially premixed combustion (PPC) is one of several advanced combustion concepts for the conventional diesel engine. PPC uses a separation between end of fuel injection and start of combustion, also called ignition dwell, to increase the mixing of fuel and oxidizer. This has been shown to be beneficial for simultaneously reducing harmful emissions and fuel consumption. The ignition dwell can be increased by means of exhaust gas recirculation (EGR) or lower intake temperature. However, the most effective means is to use a fuel with high research octane number (RON). Methanol has a RON of 109 and a recent study found that methanol can be used effectively in PPC mode, with multiple injections, to yield high brake efficiency. However, the early start of injection (SOI) timings in this study were noted as a potential issue due to increased combustion sensitivity. Therefore, the present study attempts to quantify the changes in engine performance for different injection strategies.
Technical Paper

Experimental assessment of ozone addition potential in direct injection compression ignition engines

2019-08-15
2019-24-0118
The potential of ozone addition in compression ignition engines is investigated experimentally in this paper. Experiments were carried out in an optically accessible single cylinder engine equipped with a common rail direct injection system. A commercially available ozone generator (P <100W) was used to add to the intake flow a controlled amount of ozone. EU Diesel fuel (CN 54) and a Naphtha fuel (CN 33) were tested investigating the impact of Ozone in conventional diesel combustion and LTC cases (e.g. high EGR rate). Minimal ozone concentration in the intake flow (10 ppm) demonstrated to reduce significantly the ignition delay. However, the impact observed strongly depends on the engine conditions tested and, in general, this effect observed becomes significant in conditions characterized by a long ignition delay: low intake temperature, high dilution, and low CN fuel.
Technical Paper

Direct Injection Compression-Ignition Diesel-Methanol Blends Engine for Non-road Applications

2019-08-15
2019-24-0139
It is a promising approach to use methanol as a clean and low carbon alternative fuel for the non-road energy utilization sector and ultimately for the fight against the global climate change. This paper presents a numerical simulation of the performance and emission characteristics of neat methanol and diesel/methanol dual fuel combustion processes based on Yuchai YC6M series Heavy-Duty engine bench tests. An effective reduction of soot emission was observed with increased methanol content in the blends. Nitrogen oxide (NOx) and soot emission control strategies were also investigated at length. At high loads, if the mass fraction of methanol in the blend is controlled less than 40%, the NOx emissions of the engine would be decreased by approximately 12% while the soot emissions decreased by approximately 95%. The results indicate that the methanol engine is feasible for non-road applications.
Technical Paper

Strive for Zero Emission Impact from Hybrid Vehicles

2019-08-15
2019-24-0146
Since several decades, passenger cars and light duty vehicles (LDV) reach full pollutant conversion during warm up conditions; the major challenge has been represented by the cold start and warming up strategies. The focus on technology developments of exhaust after treatment systems have been done in the thermal management in order to reach the warm up conditions as soon as possible. A new challenge is now represented by the Real Driving Emission Regulation as this bring more various, and not any longer cycle defined, Cold Start Conditions. On the other hand, once the full conversion has been reached, it would be beneficial for many EATS components if the exhaust gas temperature could be lowered. To take significant further emission steps, approaching e.g. zero emission concepts, we investigate to bring in electrical heating catalyst (EHC) and emission trap approaches. The clear goal is to have the right temperature in the right place at the right time.
Technical Paper

Reactivity Analysis and Modeling of NOx purification Considering Reactions on Cu active sites and Brønsted acid sites in a Cu-chabazite SCR catalyst

2019-08-15
2019-24-0150
In this study, the NOx purification reactivity of a Cu-chabazite SCR catalyst was analyzed over a wide temperature range based on the NH3-SCR mechanism considering Cu redox reactions and reactions on a Brønsted acid site. It was revealed that the De-NOx reactions on the active site of Cu proceeded in different paths at lower and higher temperatures. This means that the rate-limiting step of SCR reactions was changed as each temperature. The reaction rate of NOx purification on a Cu site less than 200 °C was determined by the reaction rate of oxidation of Cu sites. On the other hand, the NH3 adsorption on Cu sites played a dominant role in NOx purification at temperature range higher than 300°C. Moreover, it was also observed that the Cu reaction site took different states at low and high temperatures during the NOx purification and was estimated that the valence state of a Cu site was changed as the temperature increased.
Technical Paper

Analysis of the emission conversion performance of gasoline particulate filters and four-way catalysts over lifetime

2019-08-15
2019-24-0156
Gasoline particulate filters (GPF) recently entered the market, and are already regarded a state-of-the-art solution for gasoline exhaust aftertreatment systems to enable EU6d-TEMP fulfilment and beyond. Due to their rapid market introduction, extensive field experience with GPFs is not yet available. Especially for four-way catalytic converters, the prognosis of the emission conversion performance over lifetime poses an ambitious challenge, which significantly influences future catalyst diagnosis calibrations. In the first part of the paper, experimental GPF ash loading results are presented. Since most of the ash accumulated in the filter results from the combustion of lubricating oil additives, a burner test bench with a purpose-designed oil injection system was chosen for the investigations. The analysis of the backpressure results show that, contrary to high soot loadings, the ash load has a relatively low impact on engine performance and fuel consumption.
X