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Abstract Fluid mechanical design of the cylinder charge motion is an important part of an engine development. In the present contribution an intake port geometry is proposed that can be used as a test case for intake port flow simulations. The objective is to fill the gap between generic test cases, such as the backward facing step or the sudden expansion, and simulations of proprietary intake ports, which are barely accessible in the community. For the intake geometry measurement data was generated on a flow-through test bench and a wall-modeled LES-simulation using a hybrid RANS/LES approach for near-wall regions was conducted. The objective is to generate and analyze a reference flow case. Since mesh convergence studies are too costly for scale resolving approaches only one simulation was done, but on a very fine and mostly block-structured numerical mesh to achieve minimal numerical dissipation.

WRAPFORM is a mathematical model and computer program for calculating binder wrap surface shape. It employs punch-opening line of the die as a geometric input and does not use the complete binder surface. This paper presents WRAPFORM-II, an improvement of the WRAPFORM model by including the binder surface geometry in the simulation. The new model has been applied to several dies and results are compared to those of the base WRAPFORM model. For a decklid die reported in the literature, whose simulated binder wrap showed bifurcation possibilities, straightforward application of WRAPFORM-II predicts a more plausible result which is consistent with the original design intent. In another case, WRAPFORM-II predicted the feasibility of a design to put more material into the die cavity. Other applications show slightly improved simulation results by using WRAPFORM-II.

Vehicle water wading capability refers to vehicle functional part integrity (e.g. engine under-tray, bumper cover, plastic sill cover etc.) when travelling through water. Wade testing involves vehicles being driven through different depths of water at various speeds. The test is repeated and under-body functional parts are inspected afterwards for damage. Lack of CAE capability for wading equates to late detection of failure modes which inevitably leads to expensive design change, and potentially affects program timing. It is thus of paramount importance to have a CAE capability in this area to give design loads to start with. Computational fluid dynamics (CFD) software is used to model a vehicle travelling through water at various speeds. A non-classical CFD approach was deemed necessary to model this. To validate the method, experimental testing with a simplified block was done and then verified with CFD modelling.

In closed wall test sections the total correction to the measured drag usually consists of several parts: solid blockage corrections related to the displacement of the model, horizontal buoyancy corrections due to empty tunnel gradients and the wake blockage corrections, which are necessary to handle effects created by the displacement effect of the wake. The latter will be investigated in more detail in the paper. The wake blockage correction usually consists of two parts: a correction to the measured dynamic pressure (q-correction) and a gradient correction, the so-called wake induced drag increment. Both corrections are directly dependent on the source strength which is equivalent to the displacement effect of the wake. Therefore the displacement of the wake is analyzed in more detail.

Detailed wake surveys were performed with a 1/8th scale model, hatchback car in a low-speed, wind tunnel. The tests were conducted at a freestream velocity of 20m.s-1 giving a Reynolds number of 6.0 ×105 based on the model length. PIV was used to obtain cross-flow velocities at four wake survey locations. At one wake position the effect of hatchback geometry was investigated. Using a wake integration technique, lift and induced drag distributions along the model width, total lift and induced drag acting on the model were obtained using flow field data. The induced lift and drag coefficients were found to decrease downstream of the model due to viscous dissipation. A hatchback angle of 30° was found to produce the greatest induced drag. The instantaneous wake structure of hatchback cars was found to be asymmetric and was not adequately described as consisting of counter-rotating C-post vortices, a concept produced by earlier time averaged data obtained elsewhere.

A technique to map the wake behind passenger cars with different rear end configurations has been developed in the full-scale automotive wind tunnel “Pininfarina”. It is based on the measurement of total pressure in the wake, using a probe which is driven by a large traversing gear. Results are presented as coloured isopressure maps. Tests have been carried out on a 1:2.5 scale car model with two different front ends and eight different rear ends. The attainable body configurations are likely to cover the majority of passenger car shapes. Wake surveys have been conducted at several distances behind each car model in order to see the wake development. The paper shows and analyzes the results obtained for these sixteen car model configurations; it also emphasizes what kind of information can be obtained by this wake survey technique.

This paper proposes a film dynamics model for liquid film resulting from fuel spray impinging on a wall surface. It is based on a thin film assumption and uses numerical particles to represent the film to be compatible with the particle spray models developed previously. The Lagrangian method is adopted to govern the transport of the film particles. A new, statistical treatment was introduced of the momentum exchange between the impinging spray and the wall film to account for the directional distribution of the impinging momentum. This model together with the previously published models for outgoing droplets constitutes a complete description of the spray wall impingement dynamics. For model validation, films resulting from impinging sprays on a flat surface with different impingement angles were calculated and the results were compared with the corresponding experimental measurements.

It was important for predicting wall heat flux to apply wall heat transfer model by taking into account of the behavior of turbulent kinetic energy and density change in wall boundary layer. Although energy equation base wall heat transfer model satisfied above requirements, local physical amounts such as turbulent kinetic energy in near wall region should be applied. In this study, in order to predict wall heat transfer by zero dimensional analysis, how to express wall heat transfer by using mean physical amounts in engine combustion chamber was considered by experimental and numerical approaches.

SI-CAI hybrid combustion, also known as spark-assisted compression ignition (SACI), is a promising concept to extend the operating range of CAI (Controlled Auto-Ignition) and achieve the smooth transition between spark ignition (SI) and CAI in the gasoline engine. In order to investigate the effect of the thermal boundary condition on the hybrid combustion, the experiments with different coolant temperatures are performed to adjust the chamber wall temperature in a gasoline engine. The experimental results indicate that increasing wall temperature would advance the combustion phasing, enlarge the peak heat release rate and shorten the combustion duration. While the capacity of the wall temperature effect on the hybrid combustion characteristics are more notable in the auto-ignition dominated hybrid combustion.

Nowadays the increase and maintenance of a car manufacturer market share is greatly influenced by the appeal its products design, wherein the headlights occupy a distinctive position. However, the headlights designers' constant search for newer and innovative designs sometimes yields difficulties regarding the thermal management of these components, requiring cautious material selection, and special care in the parabolas dimensioning and positioning of bulbs and vents in the case. This work shows how a simulation strategy based on the finite volume method can be utilized to predict the headlight airflow and plastic walls temperature distribution induced by the bulbs thermal radiation. The main goal of this modeling is to raise and treat potential temperature issues early in the development cycle, guiding the corrective design actions, and supporting the material selection and specification process.

The present study investigates the pressure drop and filtration characteristics of wall-flow diesel particulate monoliths, with the aid of a mathematical model. An analytic solution to the model equations describing exhaust gas mass and momentum conservation, in the axial direction of a monolith cell, and pressure drop across its porous walls has been obtained. The solution is in very good agreement with available experimental data on the pressure drop of a typical wall-flow monolith. The capture of diesel particles by the monolith, is described applying the theory of filtration through a bed of spherical collectors. This simple model, is in remarkable agreement with the experimental data, collected during the present and previous studies, for the accumulation mode particles (larger than 0.1 μm).

In modern engine control applications, there is a distinct trend towards model-based control schemes. There are various reasons for this trend: Physical models allow deeper insights compared to heuristic functions, controllers can be designed faster and more accurately, and the possibility of obtaining an automated application scheme for the final engine to be controlled is a significant advantage. Another reason is that if physical effects can be separated, higher order models can be applied for different subsystems. This is in contrast to heuristic functions where the determination of the various maps poses large problems and is thus only feasible for low order models. One of the most important parts of an engine management system is the air-to-fuel control. The catalytic converter requires the mean air-to-fuel ratio to be very accurate in order to reach its optimal conversion rate. Disturbances from the active carbon filter and other additional devices have to be compensated.

This paper reports on the preliminary investigation of the identification of a method to model the transient operation of a single cylinder four-stroke gasoline engine. During a transient the response of an engine and the actual fuel mixture delivered to the engine are significantly affected by the behaviour of the fuel injected into the inlet manifold. In the past, different wall-wetting theories have been developed to model and attempt to resolve this problem and one of the most definitive is investigated here along with two other theories developed at QUB. A steady state computer model of a single cylinder four-stroke spark-ignition research engine was written and validated. The three different wall-wetting theories were studied and each individually integrated into the steady state model. This allowed simulated transients to be performed on the computer and the results generated to be compared with firing transient tests.

With the increasing efficiency of D.I. Diesel engines, the heat power needed to warm the passengers compartment becomes too low during the warm-up period. So the temperature increase of oil and water may be accelerate. This paper is devoted to the understanding of the phenomena involved in this process and their modeling. A diesel engine enclosed in a calorimeter is mounted on a test bench and largely instrumented. From the recorded data, the instantaneous energy balance is set up for different running conditions. Some general trends may be pointed out. During the first minute, 50% of the fuel energy is absorbed by the heat capacity of the heavy metallic components. This part progressively decreases to the benefit of heat transferred to the coolant. Furthermore, for increasing distance from the combustion chamber in the block, the rate of temperature rise decreases. Concerning the oil temperature evolution, it lags behind the water one.

The warmup characteristics of an engine have an important impact on a variety of design issues such as performance, emissions and durability. A computer simulation has been developed which permits a detailed transient simulation of the engine warmup period from initial ambient conditions to a fully warmed up state. The simulation combines a detailed crankangle-by-crankangle calculation of in-cylinder processes and of engine air flow, with finite element heat conduction calculations of heat transfer from the gases, through the structure to the coolant. The paper describes one particular application of the simulation to the warmup of a 2.5ℓ spark ignited engine from cold start to a fully warmed up state at several speeds ranging from 1600 to 5200 rpm and loads ranging from 25% to 100% at each speed. The response of structure temperatures, charge temperature at IVC and of the exhaust temperature has been calculated and is documented in terms of characteristic warmup times.

Warmup of the Du Pont model V reactor during unchoked engine operation with air injection has been characterized by a nonreactive period, followed by a transition to an ignited condition. The early period is quenched by heat loss. The transition is gradual for hydrocarbons, but more abrupt for carbon monoxide. Model building for the warmup period is directed to the objective of developing a rapid computer simulation to predict light-off times and temperature histories for various reactor designs and operating conditions. Reactor gas temperature and chemical conversions are calculated as solutions for an ideal backmix reactor. Heat balances maintain a record of all reactor metal temperatures for the given configuration. Heat transfer by radiation, convection, and conduction is considered. The presence of a hot spot in the reactor has a strong effect on time to light-off. In addition to lowering the time, such an ignition source shows a great sensitivity to combustible concentration.

Warpage is the distortion induced by inhomogeneous shrinkage during injection molding of plastic parts. Uncontrolled warpage will result in dimensional instability and bring a lot of challenges to the mold design and part assembly. Current commercial simulation software for injection molding cannot provide consistently accurate warpage prediction, especially for semi-crystalline thermoplastics. In this study, the root cause of inconsistency in warpage prediction has been investigated by using injection molded polypropylene plaques with a wide range of process conditions. The warpage of injection molded plaques are measured and compared to the numerical predictions from Moldex3D. The study shows that with considering cooling rate effect on crystallization kinetics and using of the improved material model for residual stress calculations, good agreements are obtained between experiment and simulation results.

This paper reports experimental conversion of spent vegetable oil with bio-ethanol to long chain biodiesel fuel in presence of a new developed solid K3PO4 heterogeneous catalyst. Examined catalyst was synthesized following dipping impregnation of γ-Al2O3 solid support in an aqueous solution of potassium phosphate tri-basic K3PO4. K3PO4/γ-Al2O3 catalyst samples were distinguished based on their percentage loadings of K3PO4 (CK3PO4) and averaged particle size (dp). Produced catalyst samples were characterized in terms of their textural and surface properties using nitrogen adsorption-desorption isotherms and carbon dioxide & ammonia temperature programmed desorption techniques respectively. While the liquid phase of the product was analyzed using a GC-Mass spectroscopy technique. Ethanolysis runs were carried out following surface response methodology, central composite design (CCD).