NVH refinement of passenger vehicle is essential to customer acceptance for premium or even mid-size segment passenger cars. Hydraulic engine mount is becoming common for these segments to reduce engine bounce, idle shake and noise transfer to passenger cabin. Modern layout of hydraulic mount with integrated engine-bracket and smaller size insulator has made it cost-effective to use due to reduction of cost gap from conventional elastomeric mounts. However the downsizing and complex internal structure may create some new types of noises in passenger cabin which are very difficult to identify in initial development stage.

To face the current challenges of the automotive industry, there is a need for computational models capable to simulate the engine behavior under low-temperature and low-pressure conditions. Internal combustion engines are complex and have interconnected systems where many processes take place and influence each other. Thus, a global approach to engine simulation is suitable to study the entire engine performance. The circuits that distribute the hydraulic fluids -liquid fuels, coolants and lubricants- are critical subsystems of the engine. This work presents a 0D model which was developed and set up to make possible the simulation of hydraulic circuits in a global engine model. The model is capable of simulating flow and pressure distributions as well as heat transfer processes in a circuit. After its development, the thermo-hydraulic model was implemented in a physical based engine model called Virtual Engine Model (VEMOD), which takes into account all the relevant relations among subsystems. In the present paper, the thermo-hydraulic model is described and then it is used to simulate oil and coolant circuits of a diesel engine. The objective of the work is to validate the model under steady-state and transient operation, with focus on the thermal evolution of oil and coolant. For validation under steady-state conditions, 22 operating points were measured and simulated, some of them in cold environment. In general, good agreement was obtained between simulation and experiments. Next, the WLTP driving cycle was simulated starting from warmed-up conditions and from ambient temperature. Results were compared with the experiment, showing that modeled trends were close to those experimentally measured. Thermal evolutions of oil and coolant were predicted with mean errors between 0.7 °C and 2.1 °C. In particular, the warm-up phase was satisfactorily modeled.

Indian automobile industry is set to witness the biggest emission reforms of the last two decades with the implementation of BS6 emission norms from 1st April 2020 and Real Driving Emissions (RDE) from 1st April 2023. However, there are still a lot of unanswered questions regarding the test procedure of RDE for India. For India, adopting European RDE test procedure as it is may be a challenge because of the significant differences between India and Europe in terms of weather, geography, demography, road infrastructure, driving behavior and fuel quality. This paper discusses the detailed experimental results of Real Driving Emission tests analyzing after-treatment system configurations (LNT, sDPF, ufSCR) considering different scenarios such as test routes, test days, driving behavior etc. Variation in trip dynamics (Severity, Softness in driving), trip validity and normality and post-processed results are other key points of interests investigated. The overall activity provided great insights into the possible modifications which may be required for RDE test suitable to Indian conditions. The learning such derived will be of immense value for future design and development.

The effects of Variable Valve Timing (VVT) on Homogeneous Charge Compression Ignition (HCCI) engine energy distribution and waste heat recovery are investigated using a fully flexible Electromagnetic Variable Valve Timing (EVVT) system. The experiment is carried out in a single cylinder, 657 cc, port fuel injection engine fueled with n-heptane. Exergy analysis is performed to understand the relative contribution of different loss mechanisms in HCCI engines and how VVT changes these contributions. It is found that HCCI engine brake thermal efficiency, the Combined Heat and Power (CHP) power to heat ratio, the first and the second law efficiencies are improved with proper valve timing. Further analysis is performed by applying the first and second law of thermodynamics to compare HCCI energy and exergy distribution to Spark Ignition (SI) combustion using Primary Reference Fuel (PRF). HCCI demonstrates higher fuel efficiency and power to heat and energy loss ratios compared to SI. The results are applicable for the development of micro-CHP systems using an HCCI engine operating at a constant engine speed with varying loads.

When considered along with Phase 2 GHG requirements, the proposed ARB NO_x emission limit of 0.02 g/bhp-hr will be very challenging to achieve as the trade-off between fuel consumption and NO_x emissions is not favorable. To meet any future ultra-low NO_x emission regulation the NO_x conversion efficiency during the cold start of the emission test cycles needs to be improved. In such a scenario, apart from changes in aftertreatment layout and formulation, additional heating measures will be required.

Superchargers are engine driven positive displacement devices which increase the air mass flow into the engine, thereby leading to a better combustion efficiency. This gives an advantage of extracting more power from the same engine [1], thereby reducing emissions and achieving a better fuel economy [2]. With emission norms getting more and more stringent, the need for boosting engine intake air becomes very important [3]. There are many types of superchargers based on design [4], out of which, the roots-type positive displacement supercharger, is discussed in here. A 1-dimensional model of supercharger gives flexibility of choosing the right aspect ratio (length to the diameter of the rotor), deciding on the clearances (a tradeoff between volumetric efficiency and manufacturing capabilities) and arriving at the inlet and discharge port dimensions. The dependency of the above parameters on mass flow rate of air and volumetric efficiency of the supercharger can be studied in good depth with a simplified one dimensional model [3]. This paper aims to present a one dimensional model of roots-type twin rotor (each 3 lobed) supercharger using pre-modeled library components on GT-Suite. This model has been validated with the test setup for different speeds and pressure ratios and is found to be accurate to the tune of min. 90% on mass flow and min. 97% on discharge temperatures. This model further assists in developing a supercharger map which helps in matching supercharger to the engine requirements.

Meeting Euro 6d NOx emission regulations lower than 80 mg/km for light duty diesel (60 mg/km gasoline) vehicles remains a challenge, especially during cold-start tests at which the selective catalyst reduction (SCR) system does not work because of low exhaust gas temperatures (light-off temperature around 200 °C). While several exhaust aftertreatment system (EATS) designs are suggested in literature, solutions with gaseous ammonia injections seem to be an efficient and cost-effective way to enhance the NOx abatement at low temperature. Compared to standard SCR systems using urea water solution (UWS) injection, gaseous NH₃ systems allow an earlier injection, prevent deposit formation and increase the NH₃ content density. However non-uniform ammonia mixture distribution upstream of the SCR catalyst remains an issue. These exhaust gas/ NH₃ inhomogeneities lead to a non-optimal NOx reduction performance, resulting in higher than expected NOx emissions and/or ammonia slip. Thus, efficient mixers upstream of the SCR are crucial for the overall EATS performance. In the experimental study reported in this article, planar laser induced fluorescence (PLIF) is used to quantify mixing performance of four novel CFD optimized static mixers in an optically accessible flow bench. The variation of boundary conditions and the change of exhaust line configurations (e.g. w/wo DOC upstream, w/wo DPF downstream) show a major effect on the mixing process and subsequently the homogeneity of the ammonia-exhaust gas mixture (for example: drop in uniformity index from UI = 0.95 to UI = 0.60 for a blade mixer design). This points out the need to purposefully design and optimize static mixers for a specific exhaust line configuration.

The present study experimentally examines the low temperature autoignition area of isooctane within the in-cylinder pressure - in-cylinder temperature map.

Construction vehicles own some inherent characteristics, such as low velocity, high power and following heavy heat flux et al. Aiming at decreasing flow resistance and managing airflow, a 39 ton single drum road roller from one of the biggest manufactures in China was employed as a research target to seek out the effect of air flow resistance on the performance of its heat dissipation system. For a start, a simplified 3D model of the road roller in a virtual wind tunnel was established with a commercial software, which was pre-processed in Gambit later. The radiators were set with heat exchanger boundary condition based on the analysis on the air-side elementary unit, as for the cooling fan, the experimental results in the wind tunnel were transformed into the corresponding boundary condition. Following that, a new design scheme was offered to assign the air flow inside the engine cabin, detail flow trajectories of which were introduced by velocity vector and path line acquired from the simulation results in FLUENT. At last, a field experiment was carried out to validate the correctness of the CFD simulation. The results showed that the outlet temperature of thermal fluid from the simulation could agree with experimental data over an acceptable range. The outlet temperature of coolant maintained around 78°C under the new scheme as ambient temperature was at 30°C, the assignment of air flow path could descend flow resistance, which could improve the heat dissipation performance for construction vehicles as well.

Intelligent transportation systems (ITSs) and advanced driver assistance systems (ADASs) are considered as key technologies for improving road safety, fuel economy and driving comfort. For various ITSs and ADASs, e.g. for energy management systems in hybrid electric vehicles and adaptive cruise control systems, the velocity prediction of the ego vehicle and the target vehicles can substantially improve the system performance and is therefore an important building block. In this paper a novel concept for cloud-based vehicle velocity prediction using seasonal autoregressive integrated moving average (SARIMA) processes is proposed. The concept relies on collecting velocity profiles and estimating SARIMA processes using the collected velocity profiles for distinct road segments in a cloud (offboard). When a vehicle enters a road segment, the SARIMA model for the road segment is transmitted from the cloud to the vehicle for velocity prediction (onboard). The actual velocity profiles are transmitted from the vehicle back to the cloud for updating the SARIMA models. For quantifying the prediction uncertainty, an analytical formulation of the prediction bounds is provided. Such an analytical formulation is essential for robust control design but not available in most existing concepts. Throughout the paper the theoretical findings are evaluated utilizing real measurement data from highway driving. Moreover, the proposed concept is compared with a concept from the literature relying on artificial neural networks. The evaluation and comparison indicate that the concept based on SARIMA processes provides a good compromise between prediction accuracy and computational effort. Particularly real-time requirements on velocity prediction in many ITSs and ADASs can be satisfied.