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Battery Electric Vehicles and Extended Range Electric Vehicles, like the Chevrolet Volt, can use electrical energy from the Grid to meet the majority of a driver�s transportation needs. This has the positive societal effects of displace petroleum consumption and associated pollutants from combustion on a well to wheels basis, as well as reduced energy costs for the driver. CO2 may also be lower, but this depends upon the nature of the grid energy generation. There is a mix of sources � coal-fired, gas -fired, nuclear or renewables, like hydro, solar, wind or biomass for grid electrical energy. This mix changes by region, and also on the weather and time of day. By monitoring the grid mix and communicating it to drivers (or to their vehicles) in real-time, electrically driven vehicles may be recharged to take advantage of the lowest CO2, and potentially lower cost charging opportunities.

Automotive aerodynamics measurements and simulations now routinely use a moving ground and rotating wheels (MVG&RW), which is more representative of on-road conditions than the fixed ground-fixed wheel (FG&FW) alternative. This can be understood as a combination of three elements: (a) moving ground (MVG), (b) rotating front wheels (RWF) and (c) rotating rear wheels (RWR). The interaction of these elements with the flow field has been explored to date by mainly experimental means. This paper presents a mainly computational (CFD) investigation of the effect of RWF and RWR, in combination with MVG, on the flow field around a saloon vehicle. The influence of MVG&RW is presented both in terms of a combined change from a FG&FW baseline and the incremental effects seen by the addition of each element separately. For this vehicle, noticeable decrease in both drag and rear lift is shown when adding MVG&RW, whereas front lift shows little change.

This paper describes a method for optimization of engine settings in view of best total cost of operation fluids. Under specific legal NOX tailpipe emissions requirements the engine out NOX can be matched to the current achievable SCR NOX conversion efficiency. In view of a heavy duty long haul truck application various specific engine operation modes are defined. A heavy duty diesel engine was calibrated for all operation modes in an engine test cell. The characteristics of engine operation are demonstrated in different transient test cycles. Optimum engine operation mode (EOM) selection strategies between individual engine operation modes are discussed in view of legal test cycles and real world driving cycles which have been derived from on-road tests.

Squeak and rattle (S&R) are nonstationary annoying and unwanted noises in the car cabin that result in considerable warranty costs for car manufacturers. Introduction of cars with remarkably lower background noises and the recent emphasis on electrification and autonomous driving further stress the need for producing squeak- and rattle-free cars. Automotive manufacturers use several road disturbances for physical evaluation and verification of S&R. The excitation signals collected from these road profiles are also employed in subsystem shaker rigs and virtual simulations that are gradually replacing physical complete vehicle test and verification. Considering the need for a shorter lead time and the introduction of optimisation loops, it is necessary to have efficient and inclusive excitation load cases for robust S&R evaluation.

Current developments in automotive industry such as hybrid powertrains and the continuously increasing demands on emission control systems, are pushing complexity still further. Validation of such systems lead to a huge amount of test cases and hence extreme testing efforts on the road. At the same time the pressure to reduce costs and minimize development time is creating challenging boundaries on development teams. Therefore, it is of utmost importance to utilize testing and validation prototypes in the most efficient way. It is necessary to apply high levels of instrumentation and collect as much data as possible. And a streamlined data pipeline allows the fleet managers to get new insights from the raw data and control the validation vehicles as well as the development team in the most efficient way. In this paper we will demonstrate a data-driven approach for validation testing.

In light of the drive for energy efficiency and low CO2 emissions, extensive research is performed to reduce vehicle aerodynamic drag. The wheels are relatively shielded from the main flow compared to the exterior of the passenger car; however, they are typically responsible for around 25% of the overall vehicle drag. This contribution is large as the wheels and tyres protrude into the flow and change the flow structure around the vehicle underbody. Given that the tyre is the first part of the wheel to get in contact with the oncoming flow, its shape and features have a significant impact on the flow pattern that develops. This study aims at identifying the general effects of two main tyre features, the longitudinal rain grooves and lateral pattern grooves, using both Computational Fluid Dynamics (CFD) and wind tunnel tests. This is performed by cutting generic representations of these details into identical slick tyres.

Fuel injection is a key process influencing the performance of Gasoline Direct Injection (GDI) Engines. Injecting fuel at elevated temperature can initiate flash boiling which can lead to faster breakup, reduced penetration, and increased spray-cone angle. Thus, it impacts engine efficiency in terms of combustion quality, CO2, NOx and soot emission levels. This research deals with modelling of flash boiling processes occurring in gasoline fuel injectors. The flashing mass transfer rate is modelled by the advanced Hertz-Knudsen model considering the deviation from the thermodynamic-equilibrium conditions. The effect of nucleation-site density and its variation with degree of superheat is studied. The model is validated against benchmark test cases and a substantiated comparison with experiment is achieved.

The world of automotive engineering shows a clear direction for upcoming development trends. Stringent fleet average fuel consumption targets and CO2 penalties as well as rising fuel prices and the consumer demand to lower operating costs increases the engineering efforts to optimize fuel economy. Passenger car engines have the benefit of higher degree of technology which can be utilized to reach the challenging targets. Variable valve timing, downsizing and turbo charging, direct gasoline injection, highly sophisticated operating strategies and even more electrification are already common technologies in the automotive industry but can not be directly carried over into a motorcycle application. The major differences like very small packaging space, higher rated speeds, higher power density in combination with lower production numbers and product costs do not allow implementation such high of degree of advanced technology into small-engine applications.

In order to investigate the effects of split injection on emission formation and engine performance, experiments were carried out using a heavy duty single cylinder diesel engine. Split injections with varied dwell time and start of injection were investigated and compared with single injection cases. In order to isolate the effect of the selected parameters, other variables were kept constant. In this investigation no EGR was used. The engine was equipped with a common rail injection system with a piezo-electric injector. To interpret the observed phenomena, engine CFD simulations using the KIVA-3V code were also made. The results show that reductions in NOx emissions and brake specific fuel consumption were achieved for short dwell times whereas they both were increased when the dwell time was prolonged. No EGR was used so the soot levels were already very low in the cases of single injections.

The OBD II and EOBD legislation have significantly increased the number of system components that have to be monitored in order to avoid emissions degradation. Consequently, the algorithm design and the related calibration effort is becoming more and more challenging. Because of decreasing OBD thresholds, the monitoring strategy accuracy, which is tightly related with the components tolerances and the calibration quality, has to be improved. A model-based offline simulation of the monitoring strategies allows consideration of component and sensor tolerances as well as a first calibration optimization in the early development phase. AVL applied and improved a methodology that takes into account this information, which would require a big effort using testbed or vehicle measurements. In many cases a component influence analysis is possible before hardware is available for testbed measurements.

In order to acquire knowledge about temperature vs. equivalence ratio, T-ϕ, conditions in which emissions are formed and destroyed, T-ϕ parametric maps were constructed for: 1 Soot and soot precursors (C2H2) 2 Nitrogen oxides (NO and NO2) 3 Unburnt intermediates (CH2O, H2 and CO) 4 Important radicals (HO2 and OH) Each map was obtained by plotting data from a large number of simulations for various T-ϕ combinations in a zero-dimensional, 0D, closed Perfectly Stirred Reactor, PSR. Initially, the influences of elapsed reaction time, pressure and EGR level were examined, varying one parameter at a time. Then, since both the elapsed time and pressure change in an engine cycle, the maps were constructed according to engine pressure traces obtained from Computational Fluid Dynamics, CFD, simulations. Since the pressure is changing in elapsed time intervals the maps are called transient.

In order to meet future emissions legislation for Diesel engines and reduce their CO2 emissions it is necessary to improve diesel combustion by reducing the emissions it generates, while maintaining high efficiency and low fuel consumption. Advanced injection strategies offer possible ways to improve the trade-offs between NOx, PM and fuel consumption. In particular, use of high EGR levels (⥸ 40%) together with multiple injection strategies provides possibilities to reduce both engine-out NOx and soot emissions. Comparisons of optical engine measurements with CFD simulations enable detailed analysis of such combustion concepts. Thus, CFD simulations are important aids to understanding combustion phenomena, but the models used need to be able to model cases with advanced injection strategies.

During the development of the aerodynamic properties of fore coming road vehicles down scaled models are often used in the initial phase. However, if scale models are to be utilised even further in the aerodynamic development they have to include geometrical representatives of most of the components found in the real vehicle. As the cooling package is one of the biggest single generators of aerodynamic drag the heat exchangers are essential to include in a wind tunnel model. However, due mainly to limitations in manufacturing techniques it is complicated to make a down scaled heat exchanger and instead functional dummy heat exchangers have to be developed for scaled wind tunnel models. In this work a Computational Fluid Dynamics (CFD) code has been used to show that it is important that the simplified heat exchanger model has to be of comparable size to that of the full scale unit.

The CFD model, based on the LANL KIVA-3 computer code, modified to account for the multi-step dimethyl ether, DME/air, oxidation chemistry, was developed and used to study the neat DME combustion dynamics in a constant volume at Diesel-like conditions and in the Volvo AH10A245DI Diesel engine. Constant volume simulations confirm high ignition quality of neat DME in air. The results of engine modeling illustrate that the injection schedule used for Diesel fuel is not optimal for DME. Surprisingly, the positive gain and peak pressure levels comparable with those for Diesel fuel were obtained using an early (∼ -20 ATDC) injection through a nozzle of a larger diameter at reduced injection pressures and velocities (∼150m/s) preventing too rapid spray atomization. At these conditions, combustion heat release has a specific two-stage character with a peak value placed behind the TDC.

This paper depicts the main topics of the experimental investigation on alcohol engine development field, aiming at the engineering targets for the emission levels. The first part of this study was focused on engine design optimization for running on ethanol mixed with poly-ethylene glycol (PEG) as ignition improver. It was shown that some design changes in compression ratio, turbine casing, injector nozzle configuration and exhaust pressure governor (EPG) activation, lead to a better engine thermodynamics and its thermochemistry. The second objective of this study was the investigation of engine performance and emission levels, when the ignition improver diethyl ether (DEE) would be generated on board via catalytically dehydration of ethanol, and used directly as soluble mixture or separately fumigated.

This paper describes the development and achievement of a target engine sound for a V6 SUV in consideration of the sound quality preferences of customers in the U.S. First, a simple definition for engine sound under acceleration was found using order arrangement, frequency balance, and linearity. These elements are the product of commonly used characteristics in conventional development and can be applied simply when setting component targets. The development focused on order arrangement as the most important of these elements, and sounds with and without integer orders were selected as target candidates. Next, subjective auditory evaluations were performed in the U.S. using digitally processed sounds and an evaluation panel comprising roughly 40 subjects. The target sound was determined after classifying the results of this evaluation using cluster analysis.

The drag from the underbody, including wheels and wheel housing, constitutes a significant amount of the total aerodynamic drag of heavy vehicles. A correct simulation of the underbody boundary conditions, including rotating wheels and moving ground, has turned out to be of great importance in the minimising of the aerodynamic drag. In the current study several front wheel housing design parameters have been evaluated using Computational Fluid Dynamics (CFD). Design concepts, like enclosed inner wheel housings, underbody panel and wheel housing ventilation, were evaluated by flow analysis and comparison of the drag force contribution. It was shown that changes to the wheel housing geometry had an important impact on the local flow field and force distribution. The total drag of the vehicle decreased with reduced wheel housing volume and wheel housing ventilation can reduce the aerodynamic drag significantly provided it is designed properly.

A common fan model to use in automotive under hood simulations is the Multiple Reference Frame (MRF) model and within the industry, for this specific application, this model is well known to under predict performance. In this paper we have examined the possibilities of correcting this deficiency with a simple “speed correction”. This is done by testing and simulating a production fan in the Volvo Fan Test Rig for two operating speeds, 1200 rpm and 2400 rpm. Pressure rise, fan power and static efficiency are presented as functions of volumetric flow rate. The simulations verify that using the MRF model the common behavior of under predicting pressure rise and performance of the fan occur. In addition, this work shows that; although the MRF is not predicting fan performance correctly it constitutes a reliable fan modeling strategy.

This paper describes an analysis of the Diesel Oil Surrogate (DOS) model used at Chalmers University (Sweden), including 70 species participating in 310 reactions, and subsequent improvements prompted by the model's systematic tendency to under-predict the combustion intensity in simulations of kinetically-driven combustion modes, e.g. Homogeneous Charged Compression Ignition (HCCI). Key bases of the model are the properties of a model Diesel fuel with the molecular formula C14H28. In the vapor phase, a global reaction decomposes the starting fuel, C14H28, into its constituent components; n-heptane (C7H16) and toluene (C7H8). This global reaction was modified to yield a higher n-heptane:toluene ratio, due to the importance of preserving an n-heptane-like cetane number.

In the 1955 Le Mans race the worst crash in motor racing history occurred and this accident would change the face of motor racing for decades. After the crash numerous investigations on the disaster were performed, and fifty years after some interesting books were launched on the subject. However, a number of key questions remain unsolved; and one open area is the influence of aerodynamics on the scenario, since the Mercedes-Benz 300 SLR involved in the crash was equipped with an air-brake and its influence on the accident is basically unknown. This work may be considered as a first attempt to establish CFD as a tool to aid in resolving aerodynamic aspects in motor sport accidents and in the present paper, CFD has been used to investigate the aerodynamics and estimate the drag and lift coefficients of the Mercedes-Benz 300 SLR used in the Le Mans race of 1955.