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Technical Paper

Quantification of Linear Approximation Error for Model Predictive Control of Spark Ignited Turbocharged Engines

2019-08-15
2019-24-0014
Modern turbocharged spark-ignition engines are being equipped with an increasing number of control actuators to simultaneously meet fuel economy, emissions and performance targets. The response time variations between a given set of engine control actuators tends to be significant during transients and necessitate highly complex actuator scheduling routines. Model Predictive Control (MPC) algorithms have the potential to significantly reduce calibration and control tuning efforts as compared to current methodologies that are designed around integration of multiple single-input single-output sub-system controllers. MPC systems simultaneously generate all actuator responses by using a combination of current engine conditions and optimization of a control-oriented plant model. To achieve real-time control the engine model and optimization processes must be computationally efficient without sacrificing effectiveness.
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

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

Semi-volatile Organic Compounds From a Combined Dual Port Injection/Direct-Injection Technology Light-Duty Gasoline Vehicle

2019-08-15
2019-24-0051
Gasoline direct injection (GDI) has changed the exhaust composition in comparison with the older port fuel injection (PFI) systems. More recently, light-duty vehicle engine manufactures have combined these two technologies to take advantage of the knock benefits and fuel economy of GDI with the low particulate emission of PFI. These dual injection strategy engines have made a significant change in the combustion emission composition produced by these engines. Understanding the impact of these changes is essential for automotive companies and aftertreatment developers. A novel sampling system was designed to sample the entire exhaust generated by a dual injection strategy gasoline vehicle using the United States Federal Test Procedure (FTP). This sampling system was capable of measuring the regulated emissions as well as collecting the entire exhaust from the vehicle for unregulated emissions.
Technical Paper

Smart cylinder deactivation strategies to improve fuel economy and pollutant emissions for Diesel-powered applications

2019-08-15
2019-24-0055
Further improvement of the trade-off between CO2- and pollutant emissions is the main motivating factor for the development of new diesel engine concepts, from light-duty car applications via medium-duty commercial vehicles up to large long-haul trucks. The deactivation of one or more cylinders of a light-duty diesel engine during low load operation can be a sophisticated method to improve fuel economy and reduce especially NOx emissions at the same time. Dynamic Skip Fire (DSF) is and advanced cylinder deactivation technology, where the decision to fire or skip singular units of a multi-cylinder engine architecture is taken just prior to each firing opportunity, based on a balanced rankling of multiple input parameters.
Technical Paper

Quantification and Analyses of Knock in Gasoline Engines

2019-08-15
2019-24-0089
The continuously increasing demand for improved fuel efficiency, low-emissions and high performance in gasoline engines has led to down-sizing and down-speeding. This promising and broadly applied concept, which necessitates ever higher Break Mean Effective Pressure (BMEP), is impeded at high loads by knock, stochastic Low Speed Pre-ignition (LSPI), and mega-knock. Significant research has been conducted in recent years in the field of abnormal combustion phenomena in gasoline engines and the impacts of potential mitigation concepts by using various simulation tools. In the present study, a knock analysis methodology has been developed to investigate knock in Gasoline Engines. The strategy employs multiple techniques to quantify knock tendency and severity as well as identify outlier cycles for frequency analysis.
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

Diesel Vehicle with ultra-low NOx emissions in the city

2019-08-15
2019-24-0145
The paper discusses the technical approach to meet Euro 6d Real-Driving Emissions (RDE) requirements and beyond, with a particular focus on reducing diesel NOx emissions in urban driving situations. Novel technology aspects of the diesel powertrain are an RDE-optimized catalyst system layout to improve both low- and high-load DeNOx performance and a 48V P0-hybrid system. A key element of the powertrain concept is the advanced model based DeNOx control strategy. The optimized exhaust aftertreatment layout combines lean NOx Trap (LNT) and Selective Catalytic Reduction (SCR) technologies. For maximum low load DeNOx performance, the close-coupled SCR, consisting of an additional slice upstream of an SCR coated on filter, is assisted by an LNT. High load conditions are covered by a 2-stage SCR system with twin AdBlue® dosing. The P0 48V electric motor supports the NOx control in addition to ensuring good driving performance and fuel efficiency.
Technical Paper

Testing to the CEN CWA17379 methodology that will enable comparison of NOx emissions produced by European passenger cars during urban driving

2019-08-15
2019-24-0157
Issued by The European Committee for Standardisation (CEN), the CEN Workshop Agreement (CWA 17379 produced by CEN Workshop 90), provides, for the first time, a testing methodology to conduct on-road tests to capture emissions data, from different test centres, such that the data collected will allow the emissions performance of vehicles to be fairly compared. Its applicability to vehicles of a wide range means that it forms a valuable complement to the new Real Driving Emissions (RDE) regulation. Our presentation will share the background and details of the CEN workshop and importantly share how vehicles are performing based upon PEMS tested performed to date. Emissions Analytics will also share results from over 1,300 passenger cars PEMS tested in Europe and 800 in North America regarding real-world emissions and MPG.
Technical Paper

Optimization of Compression Ratio for Direct-Injection Diesel Engine for better fuel economy.

2019-08-15
2019-24-0165
Fuel economy is becoming one of the key parameter as it not only accounts for the profitability of commercial vehicle owner but also has impact of environment. Fuel economy gets the benefitted from optimum compression ratio in modern engines. Increasing of compression ratio of any vehicle results in improvement of emission levels and performance. This paper evaluates the optimization of Compression ratio and study its effect on Engine performance. The parameters investigated in this paper includes include; combustion bowl volume in Piston, Cylinder head gasket thickness & Piston topping as these are major contributing factors affecting clearance volume and in turn the compression ratio of engine. Based on the calculation results, an optimum Compression Ratio for the engine is selected for further Verification.
Technical Paper

Replacing twin electric fan radiator with Single fan radiator Abstract.

2019-08-15
2019-24-0181
Downsizing is one of the crucial activities being performed by every automotive engineering organisation. The main aim is to reduce – Weight, CO2 emissions and achieve cost benefit. All this is done without any compromise on performance requirement or rather with optimization of system performance. This paper evaluate one such optimization, where-in radiator assembly with two electric fan is targeted for downsizing for small commercial vehicle application. The present two fan radiator is redesigned with thinner core and use of single fan motor assembly. The performance of the heat exchange is tested for similar conditions back to back on vehicle and optimized to get the balanced benefit in terms of weight, cooling performance and importantly cost. This all is done without any modification in vehicle interface components except electrical connector for fan. The side members and brackets design is also simplified to achieve maximum weight reduction.
Technical Paper

Synergistic effect of millerization, electric supercharging and 48V mild hybrid system

2019-08-15
2019-24-0195
The hybridization of the powertrain will be indispensable concerning the CO2 emission targets of 2020 and beyond. Moreover, 48V mild hybrid systems is regarded to be the prospecting near term solution due to its cost-effective fuel consumption reduction with the minimum system change for production acceptance. In this study, the potential of fuel consumption reduction in a natural aspirated MPI engine with 48V electric super charger and other synergistic technologies was evaluated to investigate the optimized gasoline engine concept for the 48V mild hybrid vehicle. The compression ratio was increased to for thermal efficiency enhancement. Tumble ratio was increased to realize faster combustion and mitigate knocking combustion.
Technical Paper

A proposed diesel powertrain to meet future emission standards and achieve high engine efficiency

2019-08-15
2019-24-0191
Nowadays, powertrain development activity is performed on the base of fulfilling the stricter emission standards under real driving conditions (RDE). However, the pressure on automotive industry to reduce CO2 emissions in high efficient diesel applications results in lower exhaust gas temperatures. Therefore, it is highly needed to develop advanced vehicle thermal management methods to both fulfil the targets of emission standards and high thermal efficiency, without increasing dramatically the powertrain cost. The aim of this work is to experimentally demonstrate that by utilising advanced engine and ATS control methods and revising the engine hardware and subsystems can lead to significant improvement on the fuel efficiency and emissions of the conventional diesel powertrain. The revised engine includes an improved combustion system, completely revised turbocharging and air handling system whilst being heavily reworked with respect to FMEP reduction.
Technical Paper

The Methane Fuel based Turbocharged Direct Injection Engine in a Hybrid Powertrain – An Efficient Synergy

2019-08-15
2019-24-0201
There is no doubt that the modern internal combustion engine (ICE) is approaching its theoretical limits in terms of efficiency. Owed to the fact that the conversion of fuel-bound chemical energy into effectively usable power by combustion is largely defined by the fuel properties, the combustion process and the implicit phenomenon of abnormal combustion is a governing factor that limits further efficiency increases. However, the use of a knock-resistant fuel such as methane is leading to a significant raise in the average combustion pressure and total engine efficiency. In turn this requires a base engine architecture that is specially designed to cater the increased thermal and mechanical requirements so that the positive fuel properties can be fully exploited. Furthermore, an improvement of the energy balance is achieved by utilizing the kinetic energy stored in the vehicle by means of electrical recovery.
Technical Paper

Optimal Engine Re-Start Strategy on a Mild Hybrid Powertrain by Means of Up-Front Modelling

2019-08-15
2019-24-0206
The ability to switch off the internal combustion engine (ICE) during vehicle operation is a key functionality in hybrid powertrains to achieve low fuel economy. However, this can affect driveability, namely acceleration response when an ICE re-engagement due to a driver initiated torque demand is required. The ICE re-start as well as the speed and load synchronisation with the driveline and corresponding vehicle speed can lead to high response times. To avoid this issue, the operational range where the ICE can be switched off is often compromised, in turn sacrificing fuel economy. Based on a 48V off-axis P2 hybrid powertrain comprising a lay-shaft transmission we present an up-front simulation methodology that considers the relevant parameters of the ICE like air-path, turbocharger, friction, as well as the relevant mechanical and electrical parameters on the hybrid drive side, including a simplified multi-body approach to reflect the relevant vehicle and powertrain dynamics.
Technical Paper

Hybrid powertrain technology assessment through an integrated simulation approach

2019-08-15
2019-24-0198
Global automotive fuel economy and emissions pressures mean that 48V hybridisation will become a significant presence in the passenger car market. The complexity of the powertrain solutions is increasing in order to further increase fuel economy for hybrid vehicles and maintain robust emissions performance. However, this results in complex interactions between technologies which are difficult to identify through traditional development approaches, resulting in sub-optimal solutions for either vehicle attributes or cost. This paper presents the results from a simulation programme focussed on the optimisation of various advanced powertrain technologies on 48V hybrid vehicle platforms. The technologies assessed include an electrically heated catalyst, an insulated turbocharger, an electric water pump and a thermal management module (a coolant valve replacing a conventional thermostat).
Technical Paper

A comprehensive hybrid vehicle model for energetic analyses on different powertrain architectures

2019-08-15
2019-24-0064
In the global quest for preventing fossil fuel depletion and reducing air pollution, hybridization plays a fundamental role to achieve cleaner and more fuel-efficient automotive propulsion systems. While hybrid powertrains offer many opportunities, they also present new developmental challenges. Due to the many variants and possible architectures, development issues, such as the definition of powertrain concepts and the optimization of operating strategies, are becoming more and more important. The paper presents model-based fuel economy analyses of different hybrid vehicle configurations, depending on the position of the electric machine (EM). The analyses are intended to support the design of powertrain architecture and the components sizing, depending on the driving scenario, with the aim of reducing the CO2 emissions.
Technical Paper

Potential to reduce nano-particle emission in SG-DISI engine with normal butane.

2019-08-15
2019-24-0022
Under lean stratified combustion, differed from the stoichiometric homogeneous charge combustion, flame could propagate through extremely rich air-fuel mixture. The rich mixture causes considerable amount of particulate matter, but, due to large effect of efficiency improvement, the attractive point is on fuel economy compare to homogeneous charge SI combustion. The easiest way to reduce particulate matter is changing fuel to gaseous hydrocarbon, to minimize evaporating and mixing period. In this study, to reduce the particulate emission and to develop the way to mitigation of emission, the emission data of particulate under low and medium-low load conditions from normal butane fueled research engine are dealt to optimize combustion strategies, with respect to injection and ignition. Especially, particulate number density were collected in the research engine, and the causes of particulate formation were speculated with visualized combustion data.
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