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Aerodynamics plays a key role in nowadays vehicle development, aiming efficiency on fuel consumption, which leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Auto Project to be implemented in Brazil on 2017. In order to meet requirements in terms of performance, especially on aerodynamics, automakers are focusing on aero-efficient exterior designs and also adding deflectors, covers, active spoilers and several other features to meet the drag coefficient. Usually, the aerodynamics properties of a vehicle are measured in both CFD simulations and wind tunnels, which provide controlled conditions for the test that could be easily reproduced. During the real operations conditions, external factors can affect the flow over the vehicle such as cross wind in open highways.

The outside visibility through the windshield and ORVM visibility through the side glasses are critical for safe driving. The frost deposition on the Windshield and side glasses in the cold climatic condition impairs the outside and ORVM visibility during driving and hence leads to an unsafe driving condition. In India, the regulation AIS-084 governs the defrosting standard. The defrosting performance evaluation by testing cannot be performed at concept stage when the vehicle prototype is not available. It also increases the cost of vehicle development due to increase in the number of prototype used for testing. This paper explains about the in-house developed CFD methodology to evaluate the windshield defrosting performance of the vehicle in the concept stage when no vehicle proto is available and cost of countermeasure for defrosting performance improvent is very less. This methodology is implemented for some of the existing models.

Frosted windshields are common appearances during the cold season. The defrosting of the car's windshield is carried out by just blowing hot air against the inside of the pane. This yields growing temperatures also on the outside and finally makes the ice melt. What may sound quite trivial from the user's point of view is rather more complex in terms of analysis and design. The physical phenomena involved are fluid flow and heat transfer in the air on both sides of the glass as well as inside (conjugated heat transfer) and the phase change in the solidified water. For designing purposes of course complete CFD simulations and investigations in test rigs will be performed. But these are very time consuming and expensive, especially if parameter variations and optimizations tasks have to be accomplished. In this paper a modeling and simulation approach is presented, which allows a quasi 3D modeling of the defrosting of windshields based on 1D simulation techniques.

In this paper we investigate the influence of the aerodynamics of the vehicle on the performance of the washer fluid spray. A planar windshield block model with various windshield angles, as well as a “generic” passenger car shape with a fixed windshield angle, is used for the present studies. CFD simulations of the flow field and the spray trajectories are undertaken in this study. The effect of windshield angles, nozzle location and crosswind on the spray performance is presented in this paper. For very large windshield angles of around 60° (measured from the vertical plane), there is no flow separation in the hood-windshield intersection region and the spray trajectory is significantly affected by the airstream for all nozzle locations.

This paper deals with the problem of complex engine part analysis. It presents an original approach based on the use of X-ray Computed Tomography scan digitizing method. In comparison with classical digitizing method, Computed Tomography method proves to be the only solution in the case of complex parts with internal areas. A validation example for which the precision of the method is estimated, is proposed. At last, the potential of the method is illustrated through the complex example of an engine head cooling circuit for which a computational CFD calculation is made.

The salient features of modern gasoline direct injection include cavitation, flash boiling, and plume/plume interaction, depending on the operating conditions. These complex phenomena make the prediction of the spray behavior particularly difficult. The present investigation combines mass-based experimental diagnostics with an advanced, in-house modeling capability in order to provide a multi-faceted study of the Engine Combustion Network’s Spray G injector. First, x-ray tomography is used to distinguish the actual injector geometry from the nominal geometry used in past works. The actual geometry is used as the basis of multidimensional CFD simulations which are compared to x-ray radiography measurements for validation under cold conditions. The influence of nozzle diameter and corner radius are of particular interest. Next, the model is used to simulate flash-boiling conditions, in order to understand how the cold flow behavior corresponds to flashing performance.

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Zero-dimensional heat release rate models have the advantage of being both easy to handle and computationally efficient. In addition, they are capable of predicting the effects of important engine parameters on the combustion process. In this study, a zero-dimensional combustion model based on physical and chemical sub-models for local processes like injection, spray formation, ignition and combustion is presented. In terms of injection simulation, the presented model accounts for a phenomenological nozzle flow model considering the nozzle passage inlet configuration and an approach for modeling the characteristics of the Diesel spray and consequently the mixing process. A formulation for modeling the effects of intake swirl flow pattern, squish flow and injection characteristics on the in-cylinder turbulent kinetic energy is presented and compared with the CFD simulation results.

The main purpose of this study is the development of an innovative methodology for Heat Exchangers (HE) design to replace the conventional design procedures. The new procedure is based on the definition of a software package managed by modeFRONTIER, a multi-objective optimization software produced by ESTECO, able to create HE virtual models by targeting several objectives, like HE performance, optimal use of material, HE minimal weight and size and optimal manufacturability. The proposed methodology consists first in the definition of a workflow for the automatic CFD simulation of a parametric model of a periodic HE cellular element.

This paper presents a numerical study on the impact of washcoat diffusion on the overall conversion performance of catalytic converters. A comprehensive transient 1D pore diffusion reaction model is embedded in state-of-the-art 1D and 3D catalytic converter models. The pore diffusion model is discussed with its model equations and the applied diffusive transport approaches are summarized. The diffusion reaction model is validated with the help of two available analytical solutions. The impact of basic washcoat characteristics such as pore diameters or thickness on overall conversion performance is investigated by selected 1D+1D calculations. This model is also used to highlight the impact of boundary layer transfer, pore diffusion and reaction on the overall converter conversion performance. The interaction of pore diffusion and flow non-uniformities is demonstrated by 3D+1D CFD simulations.

This study proposes a novel biofuel for spark ignition (SI) engine, α-pinene (C10H16), which is non-oxygenated and thus has a gravimetric energy density comparable to that of hydrocarbon fuels. The ignition characteristics of α-pinene were evaluated in an ignition quality tester (IQT) under standard temperature and pressure conditions. The measured ignition delay time (IDT) of α-pinene is 10.5 ms, which is lower than that of iso-octane, 17.9 ms. The estimated research octane number (RON) for pinene from IQT is 85. A temperature sweep in IQT showed that that α-pinene is less reactive at low temperatures, but more reactive at high temperatures when compared to isooctane. These results suggest that α-pinene has high octane sensitivity (OS) and is suitable for operation in turbocharged SI engines. With these considerations, α-pinene was operated in a single cylinder SI engine.

Dynamic skip fire (DSF) has shown significant fuel economy improvement potential via reduction of pumping losses that generally affect throttled spark-ignition (SI) engines. In DSF operation, individual cylinders are fired on-demand near peak efficiency to satisfy driver torque demand. For vehicles with a downsized-boosted 4-cylinder engine, DSF can reduce fuel consumption by 8% in the WLTC (Class 3) drive cycle. The relatively low cost of cylinder deactivation hardware further improves the production value of DSF. Lean burn strategies in gasoline engines have also demonstrated significant fuel efficiency gains resulting from reduced pumping losses and improved thermodynamic characteristics, such as higher specific heat ratio and lower heat losses. Fuel-air mixture stratification is generally required to achieve stable combustion at low loads.

Due to the rising costs of fuel and increasingly stringent regulations, auto makers are in need of technology to enable more fuel-efficient powertrain technologies to be introduced to the marketplace. Such powertrains must not sacrifice performance, safety or driver comfort. Today's engine and powertrain manufacturers must, therefore, do more with less by achieving acceptable vehicle performance while reducing fuel consumption. One effective method to achieve this is the extreme downsizing of current direct injection spark ignited (DISI) engines through the use of high levels of boosting and cooled exhaust gas recirculation (EGR). Key challenges to highly downsized gasoline engines are retarded combustion to prevent engine knocking and the necessity to operate at air/fuel ratios that are significantly richer than the stoichiometric ratio.

Combustion concepts for future SI engines try to meet CO2-emission commitments and legislation all over the world. Where the Diesel engine has an advantage by principle, the efficiency of the SI engine has to be improved significantly, while of course the exhaust emissions must not become worse. An approach is to reduce the gas exchange losses using fully variable valve trains on the intake side of the combustion engine. OptiVent is a patented new way of controlling the mass air flow in the cylinder of a combustion engine using opening valves during the compression phase of a four stroke engine. This technology regards a wider range of variability on the valvetrain components of the engine especially for opening the valves more than one time during a cycle. On the other hand it is necessary to combine this technology with direct injection to avoid fuel losses in the exhaust system and raising the exhaust hydrocarbon emission of the engine.

This paper describes the initial works related to the study of Internal Combustion Engines, as an object of mechanical design, at the Universidad Tecnológica de Pereira. It is reported a concise, complete methodology for simple model of internal combustion engine. The emphasis of the paper is placed on the use of the in-cylinder parameters (pressure and temperature) and inertial loads in the crank-slider mechanism to derive the loads that act on all the components of the crank-slider mechanism as well as the theoretical output torque for a given geometrical structure and inertial properties. These loads can then be used to estimate the preliminary dimensions of engine components in the initial stage of engine development. To obtain the pressure and temperature inside the cylinder, under different operation parameters, such as air fuel ratio and spark angle advance, a Zero dimensional model is applied. The heat transfer from the cylinder and friction are not taken into account.

Single-cylinder spark ignition engine experiments conducted at constant speed, fixed airflow, and using isooctane as the fuel, demonstrated the effects of fuel-air mixture preparation on lean operation. Mixture preparation was changed by varying the time of fuel injection in the induction manifold, near the intake valve port. For comparison, a prevaporized fuel-air mixture was also investigated. Emphasis was placed on determining the effects of mixture preparation on combustion characteristics. Based on the results from this study, the often favored prevaporized mixture of fuel and air may not be the best diet for lean engine operation.