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Wind noise is a significant source of interior noise in automobiles at cruising conditions, potentially creating dissatisfaction with vehicle quality. While wind noise contributions at higher frequencies usually originate with transmission through greenhouse panels and sealing, the contribution coming from the underbody area often dominates the interior noise spectrum at lower frequencies. Continued pressure to reduce fuel consumption in new designs is causing more emphasis on aerodynamic performance, to reduce drag by careful management of underbody airflow at cruise. Simulation of this airflow by Computational Fluid Dynamics (CFD) tools allows early optimization of underbody shapes before expensive hardware prototypes are feasible. By combining unsteady CFD-predicted loads on the underbody panels with a structural acoustic model of the vehicle, underbody wind noise transmission could be considered in the early design phases.

Fuel efficiency for tractor/trailer combinations continues to be a key area of focus for manufacturers and suppliers in the commercial vehicle industry. Improved fuel economy of vehicles in transit can be achieved through reductions in aerodynamic drag, tire rolling resistance, and driveline losses. Fuel economy can also be increased by improving the efficiency of the thermal to mechanical energy conversion of the engine. One specific approach to improving the thermal efficiency of the engine is to implement a waste heat recovery (WHR) system that captures engine exhaust heat and converts this heat into useful mechanical power through use of a power fluid turbine expander. Several heat exchangers are required for this Rankine-based WHR system to collect and reject the waste heat before and after the turbine expander. The WHR condenser, which is the heat rejection component of this system, can be an additional part of the front-end cooling module.

Modern aerodynamic Class 8 freight tractors can improve vehicle freight efficiency and fuel economy versus older traditional style tractors when pulling Canadian style A- or B-Train double trailer long combination vehicles (LCV's) at highway speeds. This paper compares the aerodynamic performance of a current generation aerodynamic tractor with several freight hauling configurations through computational fluid dynamics evaluations using the Lattice-Boltzmann methodology. The configurations investigated include the tractor hauling a standard 53′ trailer, a platooning configuration with a 30′ separation distance, and an A-Train configuration including two 48′ trailers connected with a dolly converter. The study demonstrates CFD's capability of evaluating extremely long vehicle combinations that might be difficult to accomplish in traditional wind tunnels due to size limitations.

CO2 emission is more serious in recent years and automobile manufacturers are interested in developing technologies to reduce CO2 emissions. Among various environmental-technologies, the use of solar roof as an electric energy source has been studied extensively. For example, in order to reduce the cabin ambient temperature, automotive manufacturers offer the option of mounting a solar cell on the roof of the vehicle [1]. In this paper, we introduce the semi-transparent solar cell mounted on a curved roof glass and we propose a solar energy management system to efficiently integrate the electricity generated from the solar roof into internal combustion engine (ICE) vehicles. In order to achieve a high efficiency solar system in different driving, we improve the usable power other than peak power of solar roof. Peak power or rated power is measured power (W) in standard test condition (@ 25°C, light intensity of 1000W/m2(=1Sun)).

The primary purpose of this paper is to correlate the CFD simulations performed using PowerFLOW, a Lattice Boltzmann based method, and wind tunnel tests performed at a wind tunnel facility on 1/8th scaled tractor-trailer models. The correlations include results using an aerodynamic-type tractor paired with several trailer configurations, including a baseline trailer without any aerodynamic devices as well as combinations of trailer side skirts and a tractor-trailer gap flow management device. CFD simulations were performed in a low blockage open road environment at full scale Reynolds number to understand how the different test environments impact total aerodynamic drag values and performance deltas between trailer aerodynamic devices. There are very limited studies with the Class-8 sleeper tractor and 53ft long trailer comparing wind tunnel test and CFD simulation with and without trailer aerodynamic device. This paper is to fill this gap.

The ultimate goal for vehicle aerodynamicists is to develop vehicles that perform well on the road under real-world conditions. One of the most important metrics to evaluate vehicle performance is the drag coefficient. However, vehicle development today is performed mostly under controlled settings using wind tunnels and computational fluid dynamics (CFD) with artificially uniform upstream conditions, neglecting real-world effects due to road turbulence from wind and other vehicles. Thus, the drag coefficients computed with these methods might not be representative of the real performance of the car on the road. This might ultimately lead engineers to develop design solutions and aerodynamic devices which, while performing well in idealized conditions, do not perform well on the road. For this reason, it is important to assess the vehicle’s drag as seen in real-world environments. An effort in this direction is represented by using the wind-averaged drag.

The electrification of the internal combustion engine is an important subject of future automotive technology. By using a motorized internal combustion engine, it is possible to recover waste energy by regeneration technology and to reduce various losses that deteriorate the efficiency of the internal combustion Engine. This paper summarizes the results of the development of an engine-integrated motor that can be applied to a 48V mild hybrid system for motorization of an internal combustion engine. Like the 48V MHSG-mounted mild hybrid system designed to replace the generator in the auxiliary belt system, the motorized internal combustion engine is designed with the scalability as the top priority to minimize the additional space for the vehicle and to mount the same engine in various models.

A piston in a diesel engine is subject to the high pressure and the high thermal load. The high structural reliability is required to the piston in the automotive diesel engine and it is important to confirm the design parameters of piston in initial design stage. There are lots of research works proposing new geometries, materials and manufacturing techniques for engine pistons. But, the failures of piston occur frequently in development stage. Failure mechanisms are mainly fatigue related. This paper presents failure mechanisms of the high cycle fatigue and low cycle thermal fatigue cracks which occur on the piston during durability test using engine dynamometer. In this study, FE analysis was carried out to investigate the root cause of piston failure. The analysis includes the FE model of the piston moving system, temperature dependent material properties, mechanical and thermal loadings.

Numerical simulation of aerodynamics for vehicle development is used to meet a wide range of performance targets, including aerodynamic drag for fuel efficiency, cooling flow rates, and aerodynamic lift for vehicle handling. The aerodynamic flow field can also be used to compute the advection of small particles such as water droplets, dust, dirt, sand, etc., released into the flow domain, including the effects of mass, gravity, and the forces acting on the particles by the airflow. Previous efforts in this topic have considered the water sprays ejected by rotating wheels when driving on a wet road. The road spray carries dirt particles and can obscure the side and rear glazing. In this study, road sprays are considered in which the effects of additional water droplets resulting from splashing and dripping of particles from the wheel house and rear under body are added to help understand the patterns of dirt film accumulation on the side glass and rear glass.

Various polymer-based coatings are applied on piston skirt to reduce friction loss between the piston skirt and cylinder bore which is one of main factors of energy loss in an automotive engine system. These coatings generally consist of polymer binder (PAI) and solid lubricants (graphite or MoS₂) for low friction property. On the other hand, the present study found that PTFE as a solid lubricant and nano diamond as hard particles can be used to improve the low friction and wear resistance simultaneously. In the process of producing coating material, diamond particles pulverized to a nano size tend to agglomerate. To prevent this, silane (silicon coupling agent) treatment was applied. The inorganic functional groups of silane are attached to the nano diamond surface, which keep the diamond particles are apart.

Copper has been regarded as one of the indispensable ingredients in the brake friction materials since it provides high thermal diffusivity at the sliding interface. However, the recent regulations against environmentally hazardous ingredients limit the use of copper in the commercial friction material and much effort has been made for the alternatives. In this work, the role of the cuprous ingredients such as copper fiber, copper powder, cupric oxide (CuO), and copper sulfide (CuS) are studied using the friction materials based on commercial formulations. The investigation was performed using a full inertial brake dynamometer and 1/5 scale dynamometer for brake performance and wear test. Results showed that the cuprous ingredients played a crucial role in maintaining the stable friction film at the friction interface, resulting in improved friction stability and reduced aggressiveness against counter disk.

Long haul tractor design in the future will be challenged by freight efficiency standards and emission legislations. Along with any improvements in aerodynamics, this will also require additional cooling capacity to handle the increased heat rejection from next generation engines, waste heat recovery and exhaust gas recirculation systems. Fan engagement will also have to be minimized under highway conditions to maximize fuel economy. These seemingly contradictory requirements will require design optimization via analysis techniques capable of predicting both the aerodynamic drag and engine cooling airflow accurately. This study builds on previous work [1] using a Lattice Boltzmann based computational method on a Volvo VNL tractor trailer combination. Simulation results are compared to tests conducted at National Research Council (NRC) Canada's wind tunnel.

The accuracy of the Lattice-Boltzmann based simulation method for prediction of aerodynamic drag on a heavy truck was evaluated by comparing results to twenty percent scale model wind tunnel measurements from the University of Washington Aeronautical Laboratory (UWAL). A detailed preproduction Kenworth T2000 tractor trailer was used as the scale model. The results include a comparison of normalized drag between simulation and wind tunnel as well as percentage drag change with the addition of a radius to the rear edge of the trailer. Significant effort was involved to model all of the wind tunnel details affecting the tractor-trailer drag. These are discussed along with the results of additional simulations which were performed to study the impact of the UWAL tunnel geometry relative to a tunnel with the same blockage and constant cross-sectional area, and a case with negligible blockage.

A new noble material for automotive bumper fascia has been developed by compounding of ethylene-propylene block copolymers with ethylene-α-olefin copolymers and some additives. Also mineral fillers are added, if necessary. This material is suitable for injection molding of large parts including automotive bumper fascia. By using selected rubbers which have proper melt viscosity, molecular weight, and co-monomer content, and adding modified polymer containing polar group, it has enhanced processibility and paintability maintaining general properties such as tensile strength, impact strength at low temperature, and thermal and UV stability. The remarkable characteristics of this material is good processibility compared to the conventional TPOs. This material has especially high melt flow index(20∼30g/10min at 230°C) and stable flow behavior at the processing conditions.

Suspension system of vehicle is very important because it has an effect on ride comfort and safety. And the leaf spring is one of the major parts of commercial vehicle. By that reason it has to be designed to operate under severe condition to ensure enough endurance. But the traditional method for fatigue design needs repeated fatigue tests for each design according to its geometry, material, and operating condition. This means that a lot of time and money is needed for those tests. Thus, in this paper, a fatigue design method for leaf spring based on numerical analysis is proposed. At first, stress analysis is performed to get the stress under operation load or rig tests. And fatigue analysis is performed to get the fatigue life and to ensure the safety of leaf spring. Through this study, design parameters that play vital role in fatigue life of the leaf spring can be found out.

The use of light-weight materials in automotive engine components has increased in order to achieve better fuel efficiency and engine performance. In this study, Al alloy (AI5056) valve spring retainer can reduce a weight by 63% in comparison to steel and improve the upper limit of engine speed by about 500rpm. The Al valve spring retainer was fabricated by cold forging and coated with hard anodizing, DLC (diamond like coating), cold spray and thermal spray for better wear resistance and durability. We conclude that among these materials the DLC coating improves the wear resistance of Al valve spring retainer and has a sufficient durability after endurance testing.

Depending on the scatter of material properties, geometrical shapes and load conditions, the fatigue life of mechanical components has wide range of scatter although they were tested under same conditions. This scatter is the main reason of different results between observed and predicted fatigue life. This study shows how to estimate the fatigue life distribution by analysis. Dominant factors for fatigue life distributions and their scatter could be obtained by comparing the analysis results and fatigue test results. Applying the scatter of these factors to fatigue analysis, it was possible to predict fatigue life distributions. This will improve the reliability of fatigue life estimation, therefore a more robust and reliable component design is possible.

The importance of fuel economy and emission standards has increased rapidly with high fuel costs and new environmental regulations. This requires analysis techniques capable of designing the next generation long-haul truck to improve both fuel efficiency and cooling. In particular, it is important to have a predictive design tool to assess how exterior design changes impact aerodynamic performance. This study evaluates the use of a Lattice Boltzmann based numerical simulation and the National Research Council (NRC) Canada's wind tunnel to assess aerodynamic drag on a production Volvo VNL tractor-trailer combination. Comparisons are made between the wind tunnel and simulation to understand the influence of wind tunnel conditions on truck aerodynamic performance. The production VNL testing includes a full range of yaw angles to demonstrate the influence of cross wind on aerodynamic drag.

The combustion characteristics of a HSDI diesel engine were analyzed numerically using a reduced chemical kinetics. The reaction mechanism consisting of 26 steps and 17 species including the Zel'dovich NOx mechanism for the higher hydrocarbon fuel was implemented in the KIVA-3V. The characteristic time scale model was adopted to account for the effects of turbulent mixing on the reaction rates. The soot formation and oxidation processes are represented by Hiroyasu's model and NSC's model. The validation cases include the homogenous fuel/air mixture and the spray combustion in a constant volume chamber. After the validation, the present approach was applied to the analysis of the spray combustion processes in a HSDI diesel engine. The present approach reasonably well predicts the ignition delay, combustion processes, and emission characteristics in the high-pressure turbulent spray flame-field encountered in the practical HSDI diesel engines.

The purpose of this paper is to describe some of the technology behind the Lattice Boltzmann approach to exterior airflow simulations as incorporated into the commercial CFD code, PowerFLOW®. The fundamental approach used is the Lattice Boltzmann Method (LBM) coupled with both a turbulence model to recover the dissipation of sub-grid eddy scales and a wall model to allow reduced resolution in the near-wall region. A description of LBM and both models is given. Comparisons to methods that directly solve the Navier-Stokes equations, such as finite volume or finite element methods (hereafter, collectively referred to as RANS methods) are also presented. A demonstration of the technology is presented by comparing numerical simulations with extensive experimental test data on Ford's standard calibration models. These models were originally described in SAE paper 940323 [1].