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In the last couple of decades, countries have enacted new laws concerning environmental pollution caused by heavy-duty commercial and passenger vehicles. This is done mainly in an effort to reduce smog and health impacts caused by the different pollutions. One of the legislated pollutions, among a wide range of regulated pollutions, is nitrogen oxides (commonly abbreviated as NOx). The SCR (Selective Catalytic Reduction) was introduced in the automotive industry to reduce NOx emissions leaving the vehicle. The basic idea is to inject a urea solution (AdBlue™) in the exhaust gas before the gas enters the catalyst. The optimal working temperature for the catalyst is somewhere in the range of 300 to 400 °C. For the reactions to occur without a catalyst, the gas temperature has to be at least 800 °C. These temperatures only occur in the engine cylinder itself, during and after the combustion.

The present competitive market scenario and customer requirements demand for improved NVH quality and to meet statutory norms without increased cost. When gears are used for power transmission, gear noise is of particular concern. The noise may be created due to harmonics of the rotating and meshing internal components. This has a significant effect on the overall vehicle sound quality. Various factors contribute to gearbox noise. Some of them include shaft misalignments, gear geometry, lubrication, bearings and loose mountings. Hence it is essential to study which factors contribute to the gearbox noise and to develop countermeasures for the same. Although a number of factors may contribute to gear noise as mentioned, the scope of this paper is limited to the effect of gear geometry alone on the gearbox noise.

The implementation of an electronic differential system in a delta-type, electrically assisted, three wheel Human Powered Vehicle is the subject of this paper. The electronic differential algorithm is based on the turning angle of the vehicle and its geometrical characteristics. The theoretical analysis is applied in a realistic human powered tricycle constructed in the premises of the Alexander Technological Educational Institute of Thessaloniki. The system's efficiency is validated through test measurements performed on the rear wheels during vehicle's operation in appropriately selected routes. The measurements are performed for both typical cornering and oversteering.

Rear underrun protection device is crucial for rear impact and rear under-running of the passenger vehicles to the heavy duty trucks. Rear underrun protection device design should obey the safety regulative rules and successfully pass several test conditions. The objective and scope of this paper is the constrained optimization of the design of a rear underrun protection device (RUPD) beam of heavy duty trucks for impact loading using correlated CAE and test methodologies. In order to minimize the design iteration phase of the heavy duty truck RUPD, an effective, real-life testing correlated, finite element model have been constructed via RADIOSS software. Later on, Pareto Optimization has been applied to the finite element model, by constructing designed experiments. The best solution has been selected in terms of cost, manufacturing and performance. Finally, real-life verification testing has been applied for the correlation of the optimum solution.

An innovative Diffusive Air Jet (DAJ) Combustion Chamber concept has been introduced in the present work. The DAJ Combustion Chamber design is based on the study of rate of heat release (ROHR) curve and its correlation with emission generation. The objective is to lower the trade-off between NOx and soot without sacrificing fuel economy of Direct Injection (DI) diesel engine. DAJ Combustion Chamber modifies ROHR curve to the desired one so that it lowers engine out emissions. To study its effect, a large bore, six cylinder engine with mechanical fuel injection system has been used. Three dimensional simulation software is used for the model calibration of basic reentrant cavity. Local emissions and ROHR curve have been studied using reentrant cavity shape. It has been modified to DAJ Combustion Chamber using Air Jet Chambers (AJCs). AJCs are positioned in the three dimensional model in such a way that they affect local in-cylinder emissions.

This work is based on the development of heavy-duty diesel engines for alternative fuel use. Three diesel engines for commercial vehicle applications were studied: a 13L diesel engine was converted to a dedicated lean-burn NG engine and two diesel engines (14 and 4.25L) were converted to a dual-fuel operation with diesel-NG and diesel-LPG respectively. The dedicated NG engine conversion was achieved by means of some relevant modifications such as the reduction of the compression ratio, design of a gas injection system, design of a spark plug adapter, and implementation of a complete EMS. In relation to dual-fuel cases, some minor modifications were made to the diesel baseline engines such as the installation of the gas train components and the implementation of a gas ECU for the management of the diesel and gas injection using some CAN bus J1939 signals.

The Selective Catalytic Reduction (SCR) system installed on the exhaust line is currently widely used on Diesel heavy-duty trucks and it is considered a promising technique for light and medium duty trucks, large passenger cars and off-highway vehicles, to fulfill future emission legislation. Some vehicles of these last categories, equipped with SCR, have been already put on the market, not only in the US, where the emission legislation on Diesel vehicles is more restrictive, but also in Europe, demonstrating to be already compliant with the upcoming Euro 6. Moreover, new and more stringent emission regulations and homologation cycles are being proposed all over the world, with a consequent rapidly increasing interest for this technology. As a matter of fact, a physical model of the Diesel Exhaust Fluid (DEF) supply system is very useful, not only during the product development phase, but also for the implementation of the on-board real-time controller.

Towards the effort of reducing pollutant emissions, especially soot and nitrogen oxides, from direct injection Diesel engines, engineers have proposed various solutions, one of which is the use of a gaseous fuel as a partial supplement for liquid Diesel fuel. These engines are known as dual fuel combustion engines. A dual fuel (Diesel-CNG) engine is a base diesel engine fitted with a dual fuel conversion kit to enable use of clean burning alternative fuel like compressed natural gas. In this engine diesel and natural gas are burned simultaneously. Natural gas is fed into the cylinder along with intake air; the amount of diesel injection is reduced accordingly. Dual fuel engines have number of potential advantages like fuel flexibility, higher compression ratio, and better efficiency and less modifications on existing diesel engines. It is an ecological friendly technology due to lower PM and smoke emissions and retains the efficiency of diesel combustion.

Agriculture Tractors are widely used as prime mover either to pull or drive the “Implements” in the farms, apart from custom made equipments like Transplanter, Manure Spreader, Combine Harvester, Cotton Picker, mobile irrigation etc. which are used for particular operations in large production capacities. For larger landholdings, timely completion of the operation within the window period is the major decisive factor that drives agriculture tractor design. For small farms like in India, the productivity requirement was offset by the versatility of the equipment. Also, the farming practice varies in India due to geographical conditions such as soil types and demographic conditions such as crops types. Hence, the mechanisation level of matured market was not yet achieved in India, though the technologies are available for implementation.

To quickly and efficiently match the planetary gearset characteristic parameter of power-spilt hybrid vehicles so that their oil-saving potential can be maximized, this study proposes a parameter matching method that comprehensively considers energy management strategy and driving cycle based on an analysis of vehicle instantaneous efficiency. The method is used to match the planetary characteristic parameter of a power-split hybrid light truck. The relevant conclusions are compared with the influence of various planetary characteristic parameters on fuel consumption obtained through simulation under typical operating conditions. The simulation results show that the influence laws of the various planetary characteristic parameters on vehicle average efficiency are similar to those on fuel consumption. The proposed parameter-matching method based on vehicle efficiency analysis can effectively match the planetary characteristic parameter for power-split hybrid powertrains.

The presence of unsaturated methyl esters in biodiesel makes it susceptible to oxidation and fuel quality degradation upon long-term storage. In the present work, the effects of oxidation of Karanja biodiesel upon long-term storage on the combustion and emission characteristics of a heavy-duty truck diesel engine are studied. The Karanja biodiesel is stored for one year in a 200 litres steel barrel at room conditions to mimic commercial storage conditions. The results obtained show that compared to diesel, the start of injection of fresh and aged biodiesels are advanced by ~2-degree crank angle, and the ignition delay time is reduced. Aged biodiesel showed a slightly smaller ignition delay compares to fresh biodiesel. The fuel injection and combustion characteristics of fresh and aged biodiesels were similar at all the load conditions. Both fresh and aged biodiesels produced higher oxides of nitrogen (NOx) and lower smoke emissions compared to diesel.

Global warming due to exhaust emissions, rapid depletion of crude oil, and strict carbon control legislation has forced researchers to search biofuels as substitute for petroleum diesel fuels. Biodiesel is a renewable and oxygenated fuel. It is free from sulfur, non-toxic and a biodegradable. The different non-edible vegetable oils such as Algae, Karanja and Jatropha could be used to produce biodiesel. Biodiesel is a green fuel with an exception that it emits 15-20% more NOx as compared to diesel fuel. The emissions of nanoparticles are more hazardous to human health. The nanoparticles emission of biodiesel must be measured according to the new strict regulations. The engine performance and the lower emission characteristics, except for NOx emission, for Algae, Karanja and Jatropha oil biodiesels are similar to those of diesel fuel.

To reduce carbon dioxide emissions, the use of vehicles operating on electrification technology, such as plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) is rapidly increasing. A similar trend also exists in the field of heavy-duty vehicles, such as trucks and buses. When evaluating—via the certification test method—the fuel efficiency, electricity efficiency, and exhaust gas emission of heavy-duty vehicles that have many batteries, the powertrain, including the batteries, is modeled and investigated. However, such modeling is difficult because batteries deteriorate, and the ambient temperature fluctuates during vehicle operation. To resolve this issue, we developed a new evaluation method that enables real-time cooperative control of actual batteries and hardware-in-the-loop simulation (HILS).

Compared to conventional diesel combustion (CDC), isobaric combustion can achieve a similar or higher indicated efficiency, lower heat transfer losses, reduced nitrogen oxides (NOx) emissions; however, with a penalty of soot emissions. While the engine performance and exhaust emissions of isobaric combustion are well known, the overall flame development, in particular, the flow-field details within the flames are unclear. In this study, the performance analysis of CDC and two isobaric combustion cases was conducted, followed by high-speed imaging of Mie-scattering and soot luminosity in an optically accessible, single-cylinder heavy-duty diesel engine. From the soot luminosity imaging, qualitative flow-fields were obtained using flame image velocimetry (FIV). The peak motoring pressure (PMP) and peak cylinder pressure (PCP) of CDC are kept fixed at 50 and 70 bar, respectively.

A heavy-duty diesel engine (ETH-LAV single cylinder MTU396 heavy duty research engine) was simulated by RANS and advanced reacting flow models to gain insight into its soot and NOx emissions. Due to symmetry, a section of the engine containing a single injector-hole was simulated. Dodecane was used as a surrogate to emulate the evaporation properties of diesel and a 22-step reaction mechanism for n-heptane was used to describe combustion. The Conditional Moment Closure (CMC) method was used as the combustion model in two ways. In a more conventional modelling approach, CMC was fully interfaced with the CFD and a two-equation model was employed for determining soot while the extended Zeldovich mechanism was used for NOx. In a second approach called the Imperfectly Stirred Reactor (ISR) method, the CMC equation was integrated over space and the previous RANS-CMC solution was further analysed in a post-processing step with the focus on soot.

The EU recently decided to reduce CO2 emissions of commercial vehicle fleets by 30% until 2030. One possible way to achieve this target is to convert commercial vehicle diesel engines into stoichiometric natural gas engines. Based on this, a commercial vehicle single cylinder diesel engine with variable valve actuation and high-pressure EGR is converted into natural gas operation to increase efficiency and thus reduce CO2. Additionally, a water injection system is integrated. All three technologies are investigated on their own and in combination. To reduce longer combustion durations caused by Miller valve timing and charge dilution, a piston bowl with extra high turbulence generation is designed. Additionally, a swirl variation is carried out. The results show, that high swirl motion and high turbulence can lead to a disadvantage in efficiency despite faster combustion durations due to higher wall heat losses.

The combustion process in spark-ignition engines can vary considerably cycle by cycle, which may result in unstable engine operation. The phenomena amplify in natural gas (NG) spark-ignition (SI) engines due to the lower NG laminar flame speed compared to gasoline, and more so under lean burn conditions. The main goal of this study was to investigate the main sources and the characteristics of the cycle-by-cycle variation in heavy-duty compression ignition (CI) engines converted to NG SI operation. The experiments were conducted in a single-cylinder optically-accessible CI engine with a flat bowl-in piston that was converted to NG SI. The engine was operated at medium load under lean operating conditions, using pure methane as a natural gas surrogate. The CI to SI conversion was made through the addition of a low-pressure NG injector in the intake manifold and of a NG spark plug in place of the diesel injector.

Many aspects of battery electric vehicles are very challenging from the engineering point of view in terms of safety, weight, range, and drivability. Commercial vehicle engines are often subjected to high loads even at low speeds and this can lead to an intense increment of the battery pack temperature and stress of the cooling system. For these reasons the optimal design of the battery pack and the relative cooling system is essential. The present study deals with the challenge of designing a battery pack that satisfies both the conditions of lowest weight and efficient temperature control. The trade-off between the battery pack size and the electrical stress on the cells is considered. The electric system has the aim to substitute a 3.0 liters compression ignition engine mainly for commercial vehicles.

Advanced combustion concepts such as reactivity controlled compression ignition (RCCI) have been proven to be capable of fundamentally improve the conventional Diesel combustion by mitigating or avoiding the soot-NOx trade-off, while delivering comparable or better thermal efficiency. To further facilitate the development of the RCCI technology, a robust and possibly computationally efficient simulation framework is needed. While many successful studies have been published using 3D-CFD coupled with detailed combustion chemistry solvers, the maturity level of the 0D/1D based software solution offerings is relatively limited. The close interaction between physical and chemical processes challenges the development of predictive numerical tools, particularly when spatial information is not available.

A new approach for detecting problems with vehicle brakes by analyzing sounds emitted during braking events is proposed. Vehicle brakes emit acoustic energy as part of the braking process; the spectra of these sounds are highly dependent on the mechanical condition of the brake and can be used to detect problems. Acoustic theory indicates that as brake linings wear thinner the resonant frequency of the shoe or pad increases, potentially enabling the monitoring of lining wear through passive acoustic sensors. To test this approach, passive acoustic sensors were placed roadside at the exit of a transit bus facility for 9 months. The sensors collected almost 10,000 recordings of a fleet of 160 vehicles braking over a variety of conditions. Spectra of vehicles that had brake work performed during this period were analyzed to compare differences between new and worn friction linings.