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This paper describes the set-up and testing of a single cylinder 25cc, air cooled, 4-stroke Spark Ignition (SI) engine converted to run in Homogeneous Charge Compression Ignition (HCCI) mode with the aid of various combustion control systems. The combustion control systems were investigated regarding their effects on combustion stability and heat release phasing. Engine operation was compared with unique findings from previous work done on a very small 2-stroke HCCI engine. HCCI engine operation was possible between 1000 - 4000 rpm when using Diethyl Ether (DEE) as the test fuel. Maximum operational fuel-air equivalence ratio (Φ) was 0.75 when operating without Exhaust Gas Recirculation (EGR). This relatively high equivalence ratio was attainable due to thermal gradients induced by the high surface area to volume ratio of the small engine combustion chamber, resulting in high chamber heat transfer.

A surface modification method by electrical discharge has been developed for the valve seats of aluminum cylinder heads. This method employs a conventional electrical discharge machine to generate continuous discharge arcs between an electrode and a cylinder head, whereby the molten electrode material is transferred and clad onto the valve seat area on the cylinder head. Using this new cladding method, a wear-resistant cladding can be formed on each valve seat area in a matter of minutes and, if the same number of electrodes as valve seat areas are set one on one, all the valve seat areas can be clad simultaneously. The advantages of this method include local cladding capability, outstanding adhesion, quick cladding speed, and excellent adaptability to various types of engines. The chemical composition of the cladding was determined by a preliminary test using dynamo engines, and the durability of the cladding was evaluated using the same dynamo engines.

Manufacturers of heavy-duty diesel engines are facing increasingly stringent, emission standards. These standards have motivated new research efforts towards improving the performance of diesel engines. The objective of the present program is to develop a comprehensive analytical model of the diesel combustion process that can be used to explore the influence of design changes. This will enable industry to predict the effect of these changes on engine performance and emissions. A major benefit of the successful implementation of such models is that engine development time and costs would be reduced through their use. The computer model is based on the three-dimensional KIVA-II code, with state-of-the-art submodels for spray atomization, drop breakup / coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, and soot and radiation.

Ever increasing specific power of diesel engines has put huge demand on effective thermal management of the pistons for the desired reliability and durability. The piston temperature control is commonly achieved by injecting cooling oil into piston galleries, but the design of the cooling system as well as the boundary conditions used in FEA simulations have so far relied mostly on empirical methods. A numerical procedure using 3D computational fluid dynamics (CFD) has therefore been developed to simulate the cooling process and to estimate the cooling efficiency of gallery. The model is able to predict the detailed oil flow and heat transfer in gallery, of different designs and engine applications, under dynamic conditions. The resulted spatially resolved heat transfer coefficient from the CFD model, with better accuracy, enables improved prediction of piston temperature in finite element analysis (FEA).

A 3-D numerical analysis model of transient heat transfer among the multi-component coupling system in combustion chamber of internal combustion engine has been developed successfully in the paper. The model includes almost all solid components in combustion chamber, such as piston assembly, cylinder liner, cylinder head gasket, cylinder head, intake valves and exhaust valves, etc. With two different coupling heat transfer modes, one is the lubricant film heat conduction between two moving components, another is the contact heat conduction between two immovable solid components, and with the direct coupled-field analysis method of FEM, the heat transfer relation among the components is established. The simulation result dedicates the transient heat transfer process among the components such as moving piston assembly and cylinder liner, moving valves and cylinder head. The effect of cylinder head gasket on heat transfer among the components is also studied.

A three-dimensional model is used to compute the flow,sprays and combustion in a stratified-charge rotary engine. Wall temperatures estimated from available measurements are used as boundary conditions for the energy equation. The computations provide local and instantaneous heat fluxes on the rotor and the rotor housing. The instantaneous heat fluxes are integrated in time over one cycle of the rotor to obtain estimates of local cycle averaged heat flux through the rotor and the rotor housing. These are then used as boundary conditions in a thermal analysis of the rotor and rotor housing with known coolant-side flow rates and heat transfer coefficients. The thermal analysis is done using a finite-element three-dimensional code which provides updated estimates of the rotor and rotor housing wall temperatures. These wall temperatures agree within ±20°C of the measured wall temperatures.

A displacement based finite element model is developed to predict 3-D thermal stress induced by high temperature and temperature gradient during diesel particulate filter (DPF) regeneration. The temperature field predicted by 3-D conservation of energy is used as input. This finite element model is self-contained and independent of commercial package. It includes functions of meshing body, assembling global stiffness matrix and force vector, solving final equilibrium equations as well as post-processing. This model is validated by commercial software ANSYS and good agreement is observed. Typically, it is the peak temperature rather than temperature gradients that lead to maximum compressive thermal stress in DPF during regeneration. The maximum stress always appears at the channel corner located at the end of DPF. Parametric studies of DPF during loading and regeneration as well as the effect of particulate loading on thermal stress during regeneration are carried out.

In order to use modeling as a predictive tool for real-world particulate filter designs (segmented filters, non-axisymmetric designs), it is necessary to develop reliable 3-dimensional models. This paper presents a 3 d modeling approach, which is validated against engine-bench measurements with both FBC and CDPF systems. Special emphasis is given to the prediction of the transient inlet flow distribution, which is realized without resorting to external CFD software. The experimental and modeling results illustrate the 3-d nature of the problem, induced by the heat capacity and conductivity effects of the cement layers. It is possible to predict the localization of regeneration in certain areas of the filter (partial regeneration), as a result of poor heat transfer to thermally isolated regions in the filter. The accuracy of the model was validated by extensive comparisons with temperature measurements in 30 positions inside the filters and at various operating conditions.

CuO-water nanofluids was utilized as heat transfer medium in the cooling system of the diesel engine. By using CFD-Fluent software, for 0.5%, 1%, 3% and 5% mass concentration of nanofluids, 3-dimensional numerical simulation about flow and heat transfer process in the cooling system of engine was actualized. According to stochastic particle tracking in turbulent flow, for solid-liquid two phase flow discrete phase, the moving track of nanoparticles was traced. By this way, for CuO nanoparticles of different mass concentration nanofliuds in the cooling jacket of diesel engine, the results of the concentration distribution, velocity distribution, internal energy variation, resident time, total heat transfer and variation of total pressure reduction between inlet and outlet were ascertained.

GHP which, is the heat pump system for an air conditioning, is directly driven the compressor by a small gas engine. The NOx was reduced 70% less than a conventional gas engine with improvement of thermal efficiency. The combustion chamber shape using strong squish flow is improved in order that the pattern of a heat release is changed to be suitable. Because the relation between NOx and the thermal efficiency is the trade off relation, the air fuel ratio and the ignition timing must be precisely controlled. Detecting the change of the Pi variation calculated from the engine speed variation can control the air fuel ratio.

This paper focuses on the analysis and evaluation of acoustical design criteria to produce a plausible 3D sound field solely via headrest with integrated loudspeakers at the driver/passenger seats in the car cabin. Existing audio systems in cars utilize several distributed loudspeakers to support passengers with sound. Such configurations suffer from individual 3D audio information at each position. Therefore, we present a convincing minimal setup focusing sound solely at the passenger’s ears. The design itself plays a critical role for the optimal reproduction and control of a sound field for a specific 3D audio application. Moreover, the design facilitates the 3D audio reproduction of common channel-based, scene-based, and object-based audio formats. In addition, 3D audio reproduction enables to represent warnings regarding monitoring of the vehicle status (e.g.: seat belts, direction indicator, open doors, luggage compartment) in spatial accordance.

The objective of this study was to investigate if 3D auditory displays could be used to enhance parking assistance systems (PAS). Objective measurements and estimations of workload were used to assess the benefits of different 3D auditory displays. In today’s cars, PAS normally use a visual display together with simple sound signals to inform drivers of obstacles in close proximity. These systems rely heavily on the visual display, as the sound does not provide information about obstacles' location. This may cause the driver to lose focus on the surroundings and reduce situational awareness. Two user studies (during summer and winter) were conducted to compare three different systems. The baseline system corresponded to a system normally found in today’s cars. The other systems were designed with a 3D auditory display, conveying information of where obstacles were located through sound. A visual display was also available. Both normal parking and parallel parking was conducted.

The present work deals with the 3-D, transient, system level CFD simulation of an automotive coolant system using a 3D CFD solver Simerics MP+®. The system includes actual CAD of radiator, cooling jacket, coolant pump, bypass valve and thermostat valve. This work is in continuation of the work done by Srinivasan et al. [1] where wax melting, conjugate heat transfer, Fluid Structure Interaction (FSI) of the valve had been solved. Thermostat valve was controlled by wax phase change model which also incorporates the hysteresis effect of wax melting and solidification. The previous work dealt with the simulation of complete cycle, opening, and closing of the thermostat valve system. Besides the physics considered in the previous study, the current model also includes the treatment of cavitation to account for the presence of dissolved gases and vaporization of the liquid coolant.

A 3D computer model named AIPAC (Aircraft Ice Protection Analysis Code) suitable for thermal ice protection system parametric studies has been developed. It was derived from HASPAC, which is a 2D anti-icing model developed at Wichita State University in 2010. AIPAC is based on the finite volumes method and, similarly to HASPAC, combines a commercial Navier-Stokes flow solver with a Messinger model based thermodynamic analysis that applies internal and external flow heat transfer coefficients, pressure distribution, wall shear stress and water catch to compute wing leading edge skin temperatures, thin water flow distribution, and the location, extent and rate of icing. In addition, AIPAC was built using a transient formulation for the airfoil wall and with the capability of extruding a 3D surface grid into a volumetric grid so that a layer of ice can be added to the computational domain.

A large amount of heat is generated in electric vehicle battery packs during high rate charging, resulting in the need for effective cooling methods. In this paper, a prototype liquid cooled large format Lithium-ion battery module is modeled and tested. Experiments are conducted on the module, which includes 31Ah NMC/Graphite pouch battery cells sandwiched by a foam thermal pad and heat sinks on both sides. The module is instrumented with twenty T-type thermocouples to measure thermal characteristics including the cell and foam surface temperature, heat flux distribution, and the heat generation from batteries under up to 5C rate ultra-fast charging. Constant power loss tests are also performed in which battery loss can be directly measured.

The paper will model a welding process as a moving heat source through the work piece and investigate the effectiveness of various pre-heating mechanisms, including moving heat sources and the thermal strips. The reduction of thermal conductivity in the material around the tool due to rising temperature will be considered in the study. The paper represents an initial attempt to develop a nonlinear, time-discontinuous, p-version Galerkin method for the study of thermal effects in the Friction Stir Welding (FSW) process. Numerical results and the topics for further studies are presented.

The vehicle Heating, Ventilation and Air conditioning (HVAC) system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation along with time to reach comfortable condition for human. Simulating long transient vehicle cabin for thermal comfort evaluation is computationally expensive and involves complex cabin material modelling.

A Lagrangian random vortex-boundary element method has been developed for the simulation of unsteady incompressible flow inside three-dimensional domains with time-dependent boundaries, similar to IC engines. The solution method is entirely grid-free in the fluid domain and eliminates the difficult task of volumetric meshing of the complex engine geometry. Furthermore, due to the Lagrangian evaluation of the convective processes, numerical viscosity is virtually removed; thus permitting the direct simulation of flow at high Reynolds numbers. In this paper, a brief description of the numerical methodology is given, followed by an example of induction flow in an off-centered port-cylinder assembly with a harmonically driven piston and a valve seat situated directly below the port. The predicted flow is shown to resemble the flow visualization results of a laboratory experiment, despite the crude approximation used to represent the geometry.