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Abstract The vehicle attributes developed for emerging markets like India are unique because of different topographical conditions, diversity and culture within the different states. Major attributes in vehicle development process is development of safe and sustainable vehicle systems (steering, brakes etc.) for the driver. India is presently an emerging market for automotive sector. With booming economy, purchasing power of the consumer has gone up in the past few years. Most of young population of India have started buying the cars. At the same time, India’s road infrastructure, vehicle regulations have exalted over the years. The consumer cognizance towards the vehicles have started changing now. They want safer, robust system in their vehicles with new convenience features at affordable cost. In recent years, almost all OEM’s in India have migrated steering systems from HPAS to EPAS for payback on fuel economy and weight.

Abstract Estimating the power demand of a steering system is one of the main tasks during steering system development in the concept phase of a vehicle development process. Most critical for typical axle kinematics are parking maneuvers with simultaneously high rack forces and velocities. Therefore, the focus of the article is a tire model for standstill, which can be parametrized without measurements, only having tire dimensions and conditions (inflation pressure and wheel load) as input. Combined with a double-track model, a vehicle model is developed, which is able to predict the rack force and is fully applicable during the concept phase. The article demonstrates quantitatively that the tie rod forces, and thereby especially the tire bore torque, cause the largest fraction of the power demand at the rack. For this reason, the prediction of the bore torque is investigated in detail, whereby basic approaches from the literature are analyzed and enhanced.

Abstract In order to improve robustness of vehicle dynamic performance, a steering mechanism model is proposed with alignment parameters of front wheel based on preference function method. In the steering mechanism model controllable variables include the trapezoid connection length, the base angle of steering trapezoid, the kingpin inclination angle, caster, camber and uncontrollable variables include load and initial braking velocity. Optimization objective is some vehicle dynamic performance. In the preference function method the individual performance preference and preference aggregation in designing variable space and performance variable space are analyzed. The individual performance preference includes the controllable variable preference, noise factor preference and optimization objective preference. The aggregation function is developed by aggregating all the individual performance preferences.

Abstract In this article, a hierarchical coordinated control algorithm for integrating active rear steering and driving/braking force distribution (ARS+D/BFD) was presented. The upper-level control was synthesized to generate the required rear steering angle and external yaw moment by using a sliding-mode controller. In the lower-level controller, a control allocation algorithm considering driving/braking actuators and tire forces constraints was designed to assign the desired yaw moment to the four wheels. To this end, an optimization problem including several equality and inequality constraints were defined and solved analytically. Finally, computer simulation results suggest that the proposed hierarchical control scheme was able to help to achieve substantial enhancements in handling performance and stability.

Abstract Modern driver compartment restraint systems have at least three key components that work together: safety belt system, airbags, and collapsible steering column. During a crash, a steering column will collapse at a predetermined force called breakaway force. Once the force of a crash has reached the breakaway force threshold, the column will move towards the motor area. When the column moves, the drivers’ peak forces and acceleration are decreased because the time and distance that are given to decelerate are increased. The usage of a breakaway force element inside the steering column allows car manufacturers to control the movement of the steering column at a certain point during a crash. Any load below the breakaway force, such as airbag deployment and normal or misuse forces applied by the driver, is absorbed by the system. Today’s force-based systems are optimized (design/configure) using various crash configurations, leading to one specific behavior of the column.

Abstract In recent years, lean-burn gasoline Spark-Ignition (SI) engines have been a major subject of investigations. With this solution, in fact, it is possible to simultaneously reduce NOx raw emissions and fuel consumption due to decreased heat losses, higher thermodynamic efficiency, and enhanced knock resistance. However, the real applicability of this technique is strongly limited by the increase in cyclic variation and the occurrence of misfire, which are typical for the combustion of homogeneous lean air/fuel mixtures. The employment of a Pre-Chamber (PC), in which the combustion begins before proceeding in the main combustion chamber, has already shown the capability of significantly extending the lean-burn limit. In this work, the potential of an ultralean PC SI engine for a decisive improvement of the thermal efficiency is presented by means of numerical and experimental analyses.

Abstract In stationary natural gas engines, lean-burn combustion offers higher engine efficiencies with simultaneous compliance with emission regulations. A prominent problem that one encounters with lean operation is cyclic variations. Advanced ignition systems offer a potential solution as they suppress cyclic variations in addition to extending the lean ignition limit. In this article, the performance of three ignition systems-conventional spark ignition (SI), single-point laser ignition (LI), and prechamber equipped laser ignition (PCLI)-in a single-cylinder natural gas engine is presented. First, a thorough discussion regarding the efficacy of several metrics, in addition to coefficient of variation of indicated mean effective pressure (COV_IMEP), in representing combustion instability is presented. This is followed by a discussion about the performance of the three ignition systems at a single operational condition, that is, same excess air ratio (λ) and ignition timing (IT).

Abstract Safety is always a crucial aspect of developing autonomous systems, and the motivation behind this project comes from the need to address the traffic crashes occurring globally on a daily basis. The present work studies the coexistence of the novel rule-based behavioral planning framework with the five key advanced driver assistance system (ADAS) features as proposed in this article to fulfill the safety requirements and enhance the comfort of the driver/passengers to achieve a receding-horizon autopilot. This architecture utilizes data from the sensor fusion and the prediction module for the prediction time horizon of 2 s iteratively, which is continuously moving forward (hence, the receding horizon), and helps the behavior planner understand the intent of other vehicles on the road in advance.

Abstract For safe and comfortable automated driving in the urban domain, especially in complex geometries as intersections, the prediction of surrounding traffic participants is fundamental. Several works in this field focus on predicting the behavior of vulnerable road users (VRU) at crossings. However, no approaches were found dealing with predicting the interaction between turning vehicles giving right of way or cooperating with VRU, which is substantial for the trajectory planning of following vehicles. Infrastructural sensor data from an intersection in Germany enables the development of a prediction concept for vehicles interacting with VRU. Our studies show that the original criteria for classifying an interaction between vehicles and VRU—the post-encroachment time (PET)—is not suitable as ground truth criteria for the aimed prediction. Instead, a clustering-based labelling approach with k-means shows promising results in trajectory pattern distinction.

Abstract The external driving environment of an autonomous driving vehicle is complex and changeable. In this article, the trajectory tracking control with obstacle avoidance based on model predictive control was presented. Specifically, double-level control scheme by controlling the front steering angle was used in our research, and the double level is composed of the high level of model predictive controller for local trajectory planning and low level of model predictive controller for trajectory tracking. At high level, the local trajectory planner based on the point-mass model was designed. Then, at low level, the linear time-varying vehicle dynamics model was presented, and the trajectory tracking controller was proposed considering control variable, control increment, and output constraint. Finally, the trajectory tracking performance was tested in co-simulation environment with CarSim and Simulink, and the tracking errors were analyzed.

Abstract Autonomy and connectivity are considered among the most promising technologies to improve safety and mobility and reduce fuel consumption and travel delay in transportation systems. In this paper, we devise an optimal control-based trajectory planning model that can provide safe and efficient trajectories for the subject vehicle while incorporating platoon formation and lane-changing decisions. We embed this trajectory planning model in a simulation framework to quantify its fuel efficiency and travel time reduction benefits for the subject vehicle in a dynamic traffic environment. Specifically, we compare and analyze the statistical performance of different controller designs in which lane changing or platooning may be enabled, under different values of time (VoTs) for travelers.

Abstract The aim of this article is to analyze the energy recovery of synthesis gases in an internal combustion engine, in terms of both their general behavior and recommendations for their future composition in production. This article presents an experimental analysis of power and economical parameters of internal combustion engine as a source of propulsion for a cogeneration unit. The power parameters were measured using 13 various low-energy synthesis gases as fuels. Most of them are methane-free synthesis gases. The main components of these synthesis gases were hydrogen, carbon monoxide, methane, carbon dioxide, and nitrogen. The composition of the synthesis gases responded to various waste gasification technologies. The mass lower heating value of the selected synthesis gases ranged from 4 to 8 MJ/kg.

Abstract It has been shown that appropriate regulation of parameters of the gas supply system control algorithm allows to reduce the emission of selected components of the exhaust gas (carbon monoxide [CO], hydrocarbon [HC], and oxides of nitrogen [NOx]). The test engine met the Euro 6 standard on petrol and was equipped with an additional alternative multipoint fuelling system for multipoint injection (MPI) of the gaseous phase liquefied petroleum gas (LPG). The tests are comparative in nature. The first test to compare LPG petrol fuelling was carried out in the New European Driving Cycle (NEDC) where small differences in emissions were shown. The second part of the test compared emissions in the Worldwide harmonized Light vehicles Test Cycle (WLTC), wherein the initial phase there was a significant difference in emissions to the detriment of the gas supply. An innovative approach was therefore proposed to correct settings in the gas system control algorithm.

Abstract In current production natural gas/gasoline bi-fuel vehicles, fuels are supplied via port fuel injection (PFI). Injecting a gaseous fuel in the intake port significantly reduces the volumetric efficiency and consequently torque as compared to gasoline. In addition to eliminating the volumetric efficiency challenge, direct injection (DI) of natural gas (NG) can enhance the in-cylinder flow, mixing, and combustion process resulting in improved efficiency and performance. A computational fluid dynamics (CFD) approach to model high-pressure gaseous injection was developed and validated against X-ray data from Argonne’s Advanced Photon Source. NG side and central DI of various designs and injection strategies were assessed experimentally along with CFD correlation. Significant effects on combustion metrics were quantified and explained via improved understanding of the in-cylinder flow effects due to NG injection.

Abstract Directly injecting fuel in two-stroke spark-ignition (2S-SI) engines will significantly reduce fuel short-circuiting losses. The liquid phase liquefied petroleum gas (LPG) DI (LLDI) mode has not been studied on 2S-SI engines even though this fuel is widely used for transportation. In this experimental work a 2S-SI gasoline-powered engine used on three-wheelers was modified to operate in LLDI mode with an electronic engine controller. The influences of injection pressure (IP), end of injection (EOI) timing, location of the spark plug, and type of injector on performance, combustion, and emissions were studied at different operating conditions. EOI close to bottom dead center with the spark plug located near the exhaust port was the most suitable for the LLDI mode which significantly enhanced the fuel trapping efficiency and improved the thermal efficiency.

Abstract The search for new solutions for engine ignition systems and combustion of lean air-gas mixtures has led to the application of a two-stage combustion system, previously also known as turbulent jet ignition (TJI). In this article, the authors proposed using a pre-chamber filled with a rich ignition mixture, which is turned into an outgoing burning jet that facilitates the combustion of lean mixtures in the main combustion chamber. Various two-stage combustion systems were tested in a high-speed natural gas-powered combustion engine as a part of the Horizon 2020-GasOn (Gas-Only Internal Combustion Engines) research program. The results of testing the effectiveness of using various pre-chambers are discussed in this article. These tests were carried out in a selected engine’s operating range using three pre-chambers with different geometry. The first phase of the research concerned the selection of a gas supply system (injection on the intake valve or Heinzmann mixer).

Abstract The addition of a spark plug in place of the original fuel injector and fumigating natural gas (NG) inside the intake manifold is an economical way to convert heavy-duty diesel engines to NG spark-ignition (SI) operation. The literature shows that, when compared to a conventional SI engine combustion chamber, the different in-cylinder flow motion, turbulence intensity distribution, and interaction of propagating flame with chamber boundaries in these converted engines produce distinctive combustion stages. As the current understanding of how these combustion stages affect the engine performance is limited, this study used a triple-Wiebe combustion model to determine the effect of spark timing (ST) on the phasing and mass fraction of each combustion stage, at lean operation (ϕ = 0.73) and low engine speed (N = 900 rpm).

Abstract In this paper, the results of experiments to determine the effects of silicon-containing compounds in biogas on the performance of spark-ignited gas engines for use in CNG vehicles are presented. Initial research was performed on micro-CHP units, which have many features common with automotive engines, to identify engine components sensitive for silica deposition prior to investigating a practical CNG engine. The experiments on the micro-CHP units revealed that the catalyst was the most sensitive part for silica fouling, with strong impact on the reduction of NOx. With the insight gained from these experiments, an 9-week endurance test was performed on a light-duty CNG vehicle.

Abstract The effect of hydroxy (HHO) gas or Brown gas addition as a secondary fuel on the performance, exhaust emissions, and lean operation limit of a spark-ignition (SI) engine was experimentally investigated in this study. The tests were performed on a single-cylinder liquefied petroleum gas (LPG)-fueled four-stroke lean-operated SI engine. HHO gas was obtained by electrolysis using an electric current to dissociate the water molecules. The generated HHO gas was directly sent into the cylinder by mixing with the fresh air in the intake manifold without any modification and the need for storage tanks. The results showed that HHO gas addition increased the brake thermal efficiency (BTE) by 12.97% and decreased the brake-specific fuel consumption (BSFC) by 11.17%. The exhaust emission results showed that HHO gas enrichment caused an 8.72% reduction in carbon monoxide (CO) and a 21% reduction in unburned hydrocarbon (HC), while a 6.42% increment in nitrogen oxides (NOx).

Abstract Biogas, natural gas, and their usage in the diesel engine will be important in the future. For this purpose, the effects of biogas on engine performance, emissions, and engine vibrations of the diesel engines with dual fuel system are investigated in comparison with natural gas. It has also been included in evaluating the deformation of the engine oil due to hydrogen sulfide combustion reactions. In this study, a constant speed, naturally aspirated, and direct injection of the diesel engine with volume of 2.5 liter has been converted into a dual fuel system that can be included in gas fuels. In order to determine engine performance, exhaust emissions, engine vibration, and noise, the tests were carried out at load stages of 5, 10, 15, 20, and 25 kW and at a constant speed of 1500 rpm. The experiments were first performed in a mono operation condition of the conventional diesel fuel.