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Technical Paper

Modeling the pilot injection and the ignition process of a dual fuel injector with experimental data from a combustion chamber using detailed reaction kinetics

2018-09-10
2018-01-1724
The introduction of the so called Emission Controlled Areas within the IMO Tier III legislation forces manufacturers of maritime propulsion systems to adherence to stringent emission thresholds. Dual fuel combustion, which is characterised by the injection of a small amount of fuel oil to ignite a premixed natural gas air mixture, constitutes an option to meet this target. High diesel substitution rates, resulting in very short pilot injections, oblige the injector into the ballistic working regime. This influences spray penetration, mixture formation and ignition behaviour. In the present work, a seven-hole dual fuel injector was measured in a combustion chamber to provide data for the generation of a CFD model using the commercial code AVL FIRE. The liquid and the vapour phase of the fuel spray were quantified by Mie-scattering and Schlieren-imaging technique for different chamber conditions.
Technical Paper

Emission Reduction during Cold Start by Combustion Controlled Increase of In-Cylinder Temperatures

2018-09-10
2018-01-1740
A significant share of the emissions of a vehicle with internal combustion engine is originates from the cold start. In addition to the more stringent limits for particulate emissions due the introduction of the Euro 6c standard for gasoline engines with direct injection, exhaust gas emission testing is currently preformed applying the real driving emission test procedure (RDE) required by the Euro 6d TEMP standard. The RDE test procedure is not clearly defined potentially allowing high loads immediately after the engine start. Under such circumstances the combustion chamber features low temperatures impairing emission performance and in particular provoking the excessive generation of hydrocarbon and particulate emissions. It is therefore important not only to examine the heating of the catalytic converter during the cold start, but also the preconditioning of the combustion chamber itself.
Technical Paper

Understanding the Adverse Effects of Inlet Valve Deposits on SI Engine Operation, through a Novel Technique to Create Surrogate Deposits

2018-09-10
2018-01-1742
Port fuel injected (PFI) technology remains the most common fuel delivery type present in the marketplace for gasoline spark ignition engines. Especially in the light of ever increasing vehicle lifetimes, a vehicle fleet featuring PFI technology will be present in the marketplace for decades to come. PFI engines can, in the presence of lower quality fuels and lubricants, build up harmful deposits on a range of critical engine parts including in the fuel injectors, combustion chamber and on inlet valves. Inlet valve deposits (IVDs) in more severe cases have been associated with drivability issues such as engine stumble and engine hesitation on sudden acceleration. Deposit control additives formulated in gasoline are a well-established route to managing and even reversing fuel system fouling.
Technical Paper

On board diagnostics (OBD) for multi topology hybrid electric powertrain architectures

2018-09-10
2018-01-1827
OBD is extended to electric powertrain components in Hybrid Electric Vehicle (HEV) architectures to monitor all components with influence on vehicle emissions and electrical energy consumption. Besides main electric components, like battery, inverter, electric machines including their thermal management, other electric powertrain components and systems need to be evaluated as part of comprehensive component monitoring. The multiple possible HEV topologies, lead to a complex assessment regarding the OBD relevance decision of the electric drivetrain components or systems. In addition, specificities to OBD perimeter design in the hybrid architecture need to be appropriately chosen. This paper analyzes in detail the OBD regulation requirements for HEVs in major global markets like US, Europe, China, Japan and Korea. Typical hybrid topologies from the literature and FEV’s wide library are used in this study.
Technical Paper

Impact of Engine Wear and Engine Hardware on Low Speed Pre-ignition

2018-09-10
2018-01-1663
Low speed pre-ignition (LSPI) is a well-studied phenomenon in boosted, direct-injection, spark ignition engines. The impact of lubricant formulation has received a lot of attention in recent years, yet the impact of engine hardware and engine wear on LSPI is still not fully understood. This paper addresses some of these questions using results from multiple installations of the GM 2.0L LHU engine platform. In the first part of the study, the effect of engine life on LSPI activity was observed and it was found that engines were susceptible to variations in LSPI activity during the initial LSPI tests with the activity eventually reaching a “stabilized” level. It was further observed that the LSPI activity continues to reduce at a steady rate as the engine ages and wears. For testing purposes, engine replacement was required when the engine lost LSPI discrimination ability due to reduced LSPI activity.
Technical Paper

Experimental and Numerical Investigation of Exhaust Gas Recirculation Constituent Effects on DISI Engine Knock

2018-09-10
2018-01-1677
The use of exhaust gas recirculation (EGR) in spark ignition engines has been shown to have a number of beneficial effects under specific operating conditions, such as reducing pumping work under part load conditions, reducing NOx emissions and heat transfer by lowering peak combustion temperatures, and by reducing the tendency for engine knock (caused by end-gas autoignition) under certain regimes. In this study, the latter effect is investigated, both through experiments and modeling. This study considers the effects of EGR constituents (CO2, N2, etc.) on knock both individually and combined, both experimentally and numerically. Also evaluated were the effects of engine configuration and fuel choice on the effectiveness of knock suppression with EGR addition. A parametric experimental matrix of diluents, engine configuration, and fuels was tested to measure knock limited combustion phasing of each combination.
Technical Paper

Experimental Investigation of Flame-Wall-Impingement and Near-Wall Combustion on the Piston Temperature of a Diesel Engine using Instantaneous Surface Temperature Measurements

2018-09-10
2018-01-1782
The upcoming regulations of the average fleet CO2-emissions for passenger cars in 2020 and beyond, steer the focus of Diesel engine developments towards further reduction of fuel consumption. One major drawback of internal energy conversion are wall heat losses. The heat transfer process in a reciprocating engine is dominated by forced convection, which is drastically been affected by mean flow, turbulence, flame propagation and its impingement on the combustion chamber walls. All these effects contribute to a transient heat flux resulting in a fast changing temporal and spatial temperature distribution at the surface of the combustion chamber walls. In order to quantify this changes in combustion chamber surface temperature, surface temperature measurements on the piston of a single cylinder Diesel engine were carried out. Therefore, thirteen fast-response thermocouples were installed in the piston surface.
Technical Paper

Diesel fuel improvers and their effect on microbial stability of diesel/biodiesel blends.

2018-09-10
2018-01-1751
Additives are substances that are used to improve the characteristics of fuels, typically added at concentrations of less than 1%wt. Thus, additives that enhance properties, such as cetane number or cold flow, are introduced in ultra low sulfur diesel fuel in order to upgrade its performance as well as aid its handling and distribution. Furthermore, in order to protect the engine and fuel operating system equipment, diesel fuel can be treated with corrosion inhibitors and detergents. Some additives can be combined to produce multi-functional packages. On the other hand, additives could also have an impact on other quality parameters beyond those that they are intended to boost. In a previous study it has been shown that some types of phenolic antioxidants may have the ability to retard microbial growth in biodiesel fuel, as well. Following to this, in the present study the effect of other improvers - commonly used in the diesel matrix – on fuel’s microbial stability is examined.
Technical Paper

Dual Fuel Injection (DI+PFI) for Knock Limit Extension in a Boosted SI Engine with EGR Dilution

2018-09-10
2018-01-1735
Direct and port combined fuel injection (i.e., dual injection) in SI engine is of increasing interest in the automotive field due to its fuel flexibility and selective advantages of each injection system for engine performance and emissions. Direct fuel injection engines can provide higher thermal efficiency compared to port fuel injection engines but has disadvantages of higher particulate matter emissions. Dual fuel injection as a knock suppression strategy uses gasoline in the stratified direct injection and high octane oxygenated fuels in homogeneous port fuel injection to make the end-gas less likely to auto-ignite. However, the literature contains conflicting research results regarding the knock propensity, and the effect of dual injection is still controversial. Also, the combustion stability under Exhaust Gas Recirculation (EGR) diluted condition is rarely studied.
Technical Paper

Evaluating emissions in a modern compression ignition engine using multi-dimensional PDF-based stochastic simulations and statistical surrogate generation

2018-09-10
2018-01-1739
Digital engineering workflows, involving physico-chemical simulation and advanced statistical algorithms, offer a robust and cost-effective methodology for model-based internal combustion engine development. In this paper, a modern Tier 4 capable Cat® C4.4 engine is modelled using a digital workflow that combines the probability density function (PDF)-based Stochastic Reactor Model (SRM) Engine Suite with the statistical Model Development Suite (MoDS). In particular, an advanced multi-zonal approach is developed and applied to simulate fuels, in-cylinder combustion and gas phase as well as particulate emissions characteristics, validated against measurements and benchmarked with respect to the predictive power and computational costs of the baseline model. The multi-zonal SRM characterises the combustion chamber on the basis of different multi-dimensional PDFs dependent upon the bulk or the thermal boundary layer in contact with the cylinder liner.
Technical Paper

Robust Multi-Target Tracking Algorithm Based on Automotive Millimeter-Wave Radar

2018-08-07
2018-01-1601
Automotive radar can be used to detect pedestrians and vehicles and keep stable tracking of the targets. Multi-targets tracking is the key techniques when tracking in the complicated road condition. Some targets may lose alarm and there may be some false targets among the measurement because the radar would be affected seriously in the complicated road condition especially by the clutter and multi-path effect. Tracking can solve the effect of the false targets to a certain extent and provide a stable and accurate state of the targets. How to associate the track and the measurement is important in multi-targets tracking system. A robust tracking algorithm using joint integrated probabilistic data association is proposed. Unlike the nearest neighbor method, all the possible combinations of track measurement assignments are considered and the probabilities of the joint events are calculated.
Technical Paper

Automatic Azimuth Alignment for Automotive Radar

2018-08-07
2018-01-1606
The world has witnessed the rapid development of the Advanced Driver Assist System (ADAS) industry over the past few years. Radar, as one of the most important sensors in ADAS due to the high penetration, all-weather characteristic and low cost, is studied intensively and will be applied on a large scale. Automobile radar has many applications like ACC (Advanced Cruise Control) BSD (Blind Spot Detection), LCA (Lane Change Assistant), etc., and the accuracy of the radar target detection influences the performance of ADAS. In general, range, velocity, azimuth angle and other target attributions are measured by the automotive radar, and the accuracy of the azimuth angle is more easily affected by the environment than other attributions. For the automotive radar, it is usually equipped either near a front bumper, or near a left rear and right rear bumper.
Technical Paper

System design and Model of a 3D 79GHz High Resolution Ultra-wide band millimeter-wave imaging automotive radar

2018-08-07
2018-01-1615
Automotive radar is an important environment perception sensor for advance driving assistance system. It can detect objects around the vehicle with high accuracy and it works in all bad weathers. For traditional automotive radar, it cannot measure the objects’ height. Thus, a manhole cover on the road surface or a guideboard high above the road would be taken erroneously as a non-moving car. In such cases, the adaptive cruise system would decelerate or stop the vehicle erroneously and make the driver uncomfortable. A 3D automotive radar with two-dimensional electronic scanning can measure the targets’ height as well as the targets’ azimuth angle. This paper presents a 79GHz ultra-wide band automotive 3D imaging radar. Due to the 4 GHz wide bandwidth, the range resolution of this radar can be as small as 3.75 cm.
Technical Paper

Research on Intelligent Vehicle Index and Evaluation Method

2018-08-07
2018-01-1634
As automobiles are gradually transforming from independent mechanical units to network nodes with intelligent and networked functions, the functions and performance evaluation of intelligent vehicles is facing the new challenges. At present, China has initially classified the level of intelligent vehicles on the basis of SAE, but has not yet formed a scientific, rigorous and comprehensive evaluation system. Therefore, this paper proposes the detailed intelligent evaluation ideas of intelligent vehicles in different levels from 0 to 5 and sets up a "Trinity" evaluation system covering professional evaluation, practical evaluation and market evaluation. Then, with the development progress of intelligent vehicles, we will set up the hierarchical structure of evaluation indicators basing on automated intelligence and connected intelligence.
Technical Paper

Decade of Vision-based Pedestrian Detection for Self-driving: An Experimental Survey and Evaluation

2018-08-07
2018-01-1603
With the steady progress in autonomous driving technology and the tremendous potential prospects for development, the topics about self-driving car have begun return to the center stage of AI applications. Hence, lots of efforts are made on algorithms relevant to self-driving car itself. However, few shed the light on the problem of how to testify them thoroughly, therefore unified standards for autonomous driving and testing is urgently needed. To study this problem, we begin by pedestrian detection, for that the ability of locating humans is one of the most critical problems that should be concerned about for self-driving cars. In this paper, we investigate to perform a standard evaluation to qualify different methods and detectors under a more practical manner. Specifically, we investigate several commonly used evaluation methodologies for pedestrian detection, and find out that the Caltech pedestrian detection benchmark is the most popular.
Technical Paper

Semantic Segmentation for Traffic Scene Understanding based on Mobile Networks

2018-08-07
2018-01-1600
Real-time and reliable perception of the surrounding environment is an important prerequisite for advanced driving assistance system (ADAS) and automatic driving. And vision-based detection plays a significant role in environment perception for automatic vehicles. Although deep convolutional neural networks enable efficient recognition of various objects, it has difficulty in accurately detecting special vehicles, rocks, road pile, construction site, fence and so on. In this work, we address the task of traffic scene understanding with semantic image segmentation. Both driveable area and the classification of object can be attained from the segmentation result. First, we define 29 classes of objects in traffic scenarios with different labels and modify the Deeplab V2 network. Then in order to reduce the running time, MobileNet architecture is applied to generate the feature map instead of the original models.
Technical Paper

Trajectory-tracking Control for Autonomous Driving Considering its Stability with ESP

2018-08-07
2018-01-1639
With rapid increase of vehicles on the road, safety concerns have become increasingly prominent. Since the leading cause of many traffic accidents is known to be by human drivers, developing autonomous vehicles is considered to be an effective approach to solve the problems above. Although trajectory tracking plays one of the most important roles on autonomous driving, handling the coupling between trajectory-tracking control and ESP under certain driving scenarios remains to be challenging. This paper focuses on trajectory-tracking control considering the role of ESP. A vehicle model is developed with two degrees of freedom, including vehicle lateral, and yaw motions .Based on the proposed model, the vehicle trajectory is separated into both longitudinal and lateral motion. The coupling effect of the vehicle and ESP is analyzed in the paper. The lateral trajectory-tracking algorithm is developed based on the preview follower theory.
Technical Paper

Mechanism analysis and simulation study of Automobile Millimeter Wave Radar Noise

2018-08-07
2018-01-1641
As we all know, millimeter wave radar has become one of the most important sensors of advanced driving assistance system (ADAS). However, though millimeter wave radar has strong environmental adaptability because of its unique frequency band, but its application performance is still largely affected by environmental noise, the main problem is that the environmental noise may cause the common problems such as false alarm, missing detection, inaccurate distance measurement, inaccurate velocity measurement, and inaccurate angle measurement, and so on. Therefore, R & D engineers must carry out a large number of repeated tests, it may develop a higher reliability, higher environmental adaptability of millimeter wave radar applications, extract the precise target data, and develop ADAS system more perfect. There are two ways to repeated tests, that is, the actual test and virtual test.
Technical Paper

Intelligent traffic control method for emergency vehicles prioritization based on DSRC transportation system

2018-08-07
2018-01-1644
Emergency Vehicles (EmVs) prioritization is critical to be studied in view of the effectiveness of emergency delivery. Based on DSRC(Dedicated Short Range Communication)system, adaptive traffic lights can be adopted as vehicle status and traffic lights information can be delivered to Road Side Unit (RSU). In other research work of manipulating traffic lights, only the EmVs are considered. Therefore there are still risks for non-EmVs vehicles due to insufficient time of braking. This paper provides an adaptive traffic light control method which takes into account of EmVs and non-EmVs on all the directions of lanes at the road section. In this control method, three operation modes of traffic light are proposed and the traffic light can be converted among three operation modes: normal mode, warning mode and priority mode.
Technical Paper

Decoupled Control of Vehicular Platoon with Heterogeneous Communication Delay

2018-08-07
2018-01-1645
The problems of traffic congestion, car accident and fuel scarcity can be relieved by forming vehicular platoon with small inter-vehicle spacing, where vehicles transmit their position, velocity and acceleration profiles via wireless communication networks. However, unavoidable and heterogeneous communication delays in reality among vehicles become a challenging problem in controller design process. This study presents a decoupled control method for a vehicular platoon with heterogeneous communication delays and sampled data, which are closer to the real world. Directed graphs are adopted to describe the information flow of connecting automated vehicles. By designing the state estimator, the influence of communication delays that bring the state errors can be eliminated. The complex coupled platoon control system is decoupled through the eigenvalue decomposition of information topology and the linear transformation of the whole system.
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