Browse Topic: Homologation
Wind Tunnels are complex and cost-intensive test facilities. Thus, increasing the test efficiency is an important aspect. At the same time, active aerodynamic elements gain importance for the efficiency of modern cars. For homologation, such active aero-components pose an extra level of test complexity as their control strategies, the relevant drive cycles and their aerodynamics in different positions must be considered for homologation-relevant data. Often, active components have to be manually adjusted between test runs, which is a time-consuming process because the vehicle is not integrated into the test automation. Even if so, designing a test sequence stepping through the individual settings for each component of a vehicle is a tedious task in the test session. Thus, a sophisticated integration of the wind tunnel control system with a test management system, supporting the full homologation process is one aspect of a solution. The other is the integration of the vehicle’s active aero components as controllable assets into the control system. We present an architecture of a comprehensive set of software modules, which enhance the capabilities of an automation system making highly automated homologation tests of active components possible with minimal manual actions during the test. This includes a fully traceable test process from the vehicle components to the results of each step within an automatically generated test run, during which the active components’ parameters are varied in such way, that all test requirements are satisfied. Finally, these results are transferred back to the test requirements, from which in combination with control characteristics and market-specific drive cycles the relevant homologation data of the active aero components can be obtained.
There is an increasing effort to reduce noise pollution across different industries worldwide. From a transportation standpoint, pass-by regulations aim to achieve this and have been implementing increasingly stricter emissions limits. Testing according to these standards is a requirement for homologation, but does little to help manufacturers understand why their vehicles may be failing to meet limits. Using a developed methodology such as Pass-by Source Path Contribution (SPC, also known as TPA) allows for identification of dominant contributors to the pass-by receivers along with corresponding acoustic source strengths. This approach is commonly used for passenger vehicles, but can be impractical for off-highway applications, where vehicles are often too large for most pass-by-suitable chassis dynamometers. A hybrid approach is thereby needed, where the same techniques and instrumentation used in the indoor test are applied to scenarios in an outdoor environment. This allows for determination of all the useful contribution results in a more representative environment and without limitations associated with indoor facilities. This paper demonstrates the application of this method on an off-highway vehicle for several scenarios.
Homologation is an important process in vehicle development and aerodynamics a main data contributor. The process is heavily interconnected: Production planning defines the available assemblies. Construction defines their parts and features. Sales defines the assemblies offered in different markets, where Legislation defines the rules applicable to homologation. Control engineers define the behavior of active, aerodynamically relevant components. Wind tunnels are the main test tool for the homologation, accompanied by surface-area measurement systems. Mechanics support these test operations. The prototype management provides test vehicles, while parts come from various production and prototyping sources and are stored and commissioned by logistics. Several phases of this complex process share the same context: Production timelines for assemblies and parts for each chassis-engine package define which drag coefficients or drag coefficient contributions shall be determined. Absolute and relative measurement requirements are derived and used to create tests. The test results are linked to the requirements. Drag coefficient contributions for each assembly are derived from this. Combining this data with active components’ control concepts, drive cycle definitions and market sales programs, and following legal rules, yields the drag coefficients for homologation in each market. All of this must adhere to an ISO17025-compliant process in a manageable and efficient manner [4]. This includes optimization tasks for wind tunnel use, parts and vehicle availability, and task-organization for mechanics and operators – while keeping up with short development cycles and time-to-market pressure. We present a holistic solution that enables efficient and compliant management of this complex process: Open interfaces support flexible integration of third-party systems. Modular, configurable components offer the necessary flexibility for complex workflows. Combining data handling and planning tasks keeps all information within the same context. An intuitive user interface ensures a smooth and guided user experience. This sophisticated concept can also be transferred to other homologation processes.
When designing new vehicles, the legal requirements of the countries in which the vehicles are homologated must be observed and implemented. The manufacturers try to consider the legal framework of the UN-ECE (United Nations Economic Commission for Europe), CCC (China Compulsory Certification) and FMVSS (Federal Motor Vehicle Safety Standard) 108 in the same vehicle to keep the variance low. For the appearance of the vehicle, the position of the light modules in the front of the vehicle is important. In addition to the surface requirements of lighting functions, the positions of the low beam (LB), high beam (HB) and the position of daytime running lights (DRL) are also regulated. When it comes to these mounting positions, the legislation between the US and the EU differs quite significantly. The UN-ECE legal framework does not describe the distance between the left and right Adaptive Front Lighting System with a certain value, but only requires the distance to the outer edge of the vehicle to be less than 400 mm. The FMVSS 108 on the other hand stipulates, that the distance should be "as far apart as practicable". The underlying reason for that is, that the distance and width from oncoming traffic could be misjudged if the low beam is placed too far inboard of the vehicle instead of to the outer edges. For this reason, with the support of a test person study, this paper examines different horizontal mounting positions of low beam in combination with several light setup positions, to investigate the impact of the headlight position on the distance assessment. The results can be used to design future cars in such a way that innovative design can be implemented while ensuring road safety.
Aerospace industry OEMs and suppliers are progressing their engineering processes and performance to the next maturity level gearing to digital thread solutions. Current challenges like continuous engineering, virtual certification, distributed development, consolidated virtual proving grounds, homologation, digital twin and operational applications, require well informed decision making in a comprehensive, reliable, traceable and customizable environment. In particular, in aerospace domain, with widespread tight collaborative ecosystems between integrators and suppliers, the capability of tracing each decision and its underlying artifacts becomes a key value of an engineering platform. This paper will outline a middleware approach to reuse generated artifacts and their relationships in a federated engineering environment supporting a "best tool for the job" approach by introducing a layer providing unification and consistency throughout all managed artifacts. Based on an exemplary eVTOL setup, the benefits of integrated data and workflows from specification to virtual design verification are highlighted to motivate their value towards realisation of MBSE methodologies.
Fuel economy is one of the main drivers of the automotive industry. This subject is becoming more and more important showing a clear upraising relevance tendency. The automotive community is researching and developing many solutions and trending technologies to improve the internal combustion engine, realizing its existence is under risk due to strong greenhouse gas impact. Some innovative technologies focus on the internal combustion engines replacement by other energy conversion systems. Other new technologies improve internal combustion engines efficiency but, in most of the cases, impacts on its costs and consequently on its viability, especially considering the entry level passenger cars. In these applications, the cost impact is hardly acceptable by the customers and this market represents a considerable part of the global automotive industry. Any opportunity to improve the vehicle efficiency with minimum cost is welcome. This paper intends to assess the development and application of a gear shift indicator in an entry level passenger car. This technology represents a very low cost impact because the engine control unit should add just an improved software strategy that indicates the more efficient way to drive the vehicle. In order to compare the advantages of this technology, many numerical simulations were performed considering different test cycles and two main vehicle and road conditions: empty vehicle on a plain (0%) road grade compared to a loaded vehicle on a uphill (5%) road grade. The results presented 8% fuel economy improvement for the driver that follows the gear shift indicator compared to the traditional driver that considers only the vehicle speed for gear shifting [1] following a Brazilian homologation standard [2]. This advantage in fuel economy is significant for the empty vehicle, increasing with lower cycle average speed. This paper highlights the importance of right shifting for fuel economy and reinforces the numerical simulation for time, test facility and of course costs.
In the perspective of fuel saving and emissions reduction, engine oil thermal management has not yet received the attention it deserves. Lubricating oil, in fact, should be the focus of a specific warmup action: the expected benefits is on friction reduction – mechanical efficiency improvement – but also on a positive interaction with the cooling fluid thermal dynamics. The lower thermal capacity of the circulating oil (with respect to the cooling fluid) and the instantaneous reduction of the viscosity due to temperature increase produces a faster engine overall efficiency benefit: this invites to focus specific actions on its thermal management in the direction of speeding up the temperature rise during a cold engine starting. Being the mechanical engine efficiency strongly influenced by the friction losses and considering the important benefits on oil viscosity due to a temperature increase, important beneficial effects should be observed on fuel consumption: unfortunately, the big oil quantity inside the oil sump delays the oil warm-up which is continuously heated during the engine passage but also remixed inside the oil sump in which a great oil quantity is present. So, during a homologation cycle for passenger cars and light duty engines, the oil temperature rise is dominated by the mass inside the oil sump: considering that the oil flow rate is limited by the limited engine speed of rotation. In this paper, a modified oil sump has been designed and tested on an Iveco F1C 3 L engine test bench in order to temporarily reduce the oil quantity from which the oil pump aspirates it. In this way, the oil is remixed with a smaller oil quantity inside the sump, speeding up its temperature rise. When the engine reached a thermal stabilized state, the capacity of the oil sump is restored to its full capacity. The temporarily volume reduction of the oil inside the sump is realized by modifying it with a metal septum that divides the capacity into two parts: a thermo-controlled opening links the two parts together when the oil reaches the design temperature. Fuel consumption and CO2 emission reduction have been demonstrated and this further positive result has been added to another positive action in order to further speed up its temperature, using exhaust heat to warm the oil. Fuel consumption benefits has been demonstrated and pollutants reduction has been also reported, produced by the modified thermal behavior of the whole engine due to the positive interactions with the cooling fluid.
To assess the fuel consumption of vehicles, three sets of input data are required; drive cycles, vehicle parameters, and environmental conditions. As the first part of a series of studies on real-world fuel consumption, this study focuses on the drive cycles. In principle, drive cycles should represent real-world usage. Some of them aim at a specific usage such as a city driving condition or an aggressive driving style. However, the definition of city or aggressive driving is very subjective and difficult to quantitatively correlate with the real-world usage. This study proposes a methodology to quantify the speed and dynamics of drive cycles, or vehicle speed traces in general, against the real-world usage. After reviewing parameter sets found in other studies, relative cubic speed (RCS) and positive kinetic energy (PKE) are selected to represent the speed and dynamics through energy flow balance at the wheels. The authors suggest a normalised 2-dimensional coordinate space representing speed and dynamics of the drive cycles by statistical analysis of the parameters. The suggested space can be used for quantitative mapping of homologation drive cycles onto the given real-world usage data and identify which group of customers the homologation drive cycles represent. Another potential application of the methodology is to compare the multiple coordinate spaces generated from different data sets such as different vehicle segments. To demonstrate the proposed methodology, the 2-dimensional space is generated from a collection of data logged from passenger cars. The parameters of the collection show lognormal - normal distribution and are correlated to each other. Some homologation drive cycles are mapped onto the space and are compared to the real-world data followed by a discussion of the metrics of individual drive cycles.
The motor vehicles are the main source of atmospheric pollution, especially carbon monoxide, hydrocarbons and nitrogen oxides (NOx). To reduce these emissions for environmentally acceptable levels, Europe and the United States have developed control programs, where are set emissions limits for new vehicles, which are gradually reduced over time and the compliance must be done through standardized tests in laboratories. However, Europe is facing a problem: NOx level in the cities is not being reduced in the same proportion of the homologation limits, due to two factors: the poor representativeness of the test procedures in comparison of the “real world” and the use of engine management software that produces low pollutants just in laboratory tests. Several studies about real world emissions have pointed to vehicles, approved in the laboratory, emitting in the streets about 7 up to 40 times more NOx than the homologation limit. To fix this problem, since September/2017 Europe will add to the vehicles type-approval process a real driving emissions test (Real Driving Emissions - RDE), where the vehicle must meet the limits when running in streets coupled to a portable measuring system. In order for the RDE procedure be applied effectively to the Brazilian reality, it is necessary to discuss three relevant points: the differences between the national and the European fleet, the procedure itself, focused on NOx control and the specific characteristics of Brazilian cities. This paper has the objective to discuss about RDE principles and how it can to be applied in the Brazilian reality.
A 4 wheeled vehicle with X-split brake configuration, in hydraulic circuit failed condition will have a behavior of induced sway due to braking force variation in the front and rear diagonally. With increasing vehicle speed, engine power & customer expectations, the situation becomes more critical and challenging in designing a brake system which caters in meeting the homologation requirement at an expense of vehicle sway within controllable limits of driver / customer. This paper proposes a novel approach & methodology to overcome the above situation by predicting the effect of brake force distribution variation on the vehicle swaying behavior during circuit failed braking condition. This study will quantify vehicle sway, caused due to imbalance in brake force distribution during a circuit failed braking event on X Split configuration vehicles. This study will also aid in forecasting the vehicle sway capacity of a given vehicle and do necessary corrective design amendments to reduce the sway behavior during initial development phase of system / vehicle. It briefly discusses on a case study about most feasible solution to reduce the vehicle sway by altering the brake force distribution in circuit failed condition alone, without having any change in brake force distribution during service brake condition without altering any vehicle architecture / parameters. It also provides good correlation on sway tendency through actual vehicle testing.
Increasing global efficiency of direct injection spark ignition (DISI) engine is nowadays one of the main concerns in automotive research. A conventional way to reduce DISI engine fuel consumption is through downsizing. This approach is well suited to the current homologation cycle as NEDC, but has the drawback to induce over-consumptions in customer real driving usage. Moreover, the driving cycles dedicated to EURO 6d and future regulations will evolve towards higher load operating conditions with higher particulate emissions. Therefore, efficiency of current DISI has to be strongly increased, for homologation cycle and real driving conditions. This implies to deeply understand and improve injection, mixing and flame propagation processes. This work proposes an alternative way to improve the thermodynamic efficiency of the combustion system, by coupling an increase of Compression Ratio (CR) with high levels of Exhaust Gas Recirculation (EGR) and the setup of Miller/Atkinson cycle at intake. The study is focused on the understanding of the physical phenomena involved by high CR and Miller/Atkinson type cycle. Particularly, the impact on turbulence level, air-fuel mixture, combustion efficiency and final global efficiency is assessed. Several tools presented here are used to optimize an existing downsized DISI engine: optical diagnostics, 3D simulation, and single cylinder engine optimization. Then, the impacts of the different technological components (CR, Intake valve opening duration, Valve timing, EGR…) is detailed. Finally the obtained results are discussed to draw some perspectives on the best suited engine architecture.
Adaptive driving beam (ADB), which was first homologated in the ECE world (ECE 123) in 2012 has changed the automotive Front Lighting philosophy completely. Whereas we currently live with separate low beam and high beam features, also used in a combined way, we will have in the future a camera driven light distribution, which is a kind of modified high beam light pattern. ADB is a camera based lighting system, which enables the driver to achieve at night nearly high beam visibility without glaring oncoming or proceeding vehicles and road users. Once the presence of other vehicles is detected the headlamps change the light pattern and block the light where the oncoming or proceeding vehicles are located. The typical low beam light distribution with given and specified cutoff line will only be used in small speed areas. In US this development was well recognized and NHTSA is preparing a way to enable and approve the ADB systems with specific boundary conditions also for the US market. Several surveys have proven in between that the use of ADB is contributing to safety in night time driving. Therefore the suitable application of ADB in US is a target of NHTSA with a specific modification of the standard FMVSS108. A task force group (J3069) was introduced to define these boundary conditions. The paper will give an outlook of the potential applications in the future, both in the ECE world as well as in US . Although we do see first production of ADB headlamps in ECE, both with HID and LED light source, the concept of front lighting distribution is not yet using the full advantage of the existing opportunities. Some proposals for future concepts will be given.
Due to the constant environmental preoccupation, application of increasingly sophisticated technologies for control of motor vehicle pollutants and necessity of monitoring of such systems, the Embedded Emissions Monitoring System (OBD) was implemented with the primary function of ensuring that the pollutant emissions levels stay within the homologation limits during the whole vehicle useful life. For this reason electronic systems (such as sensors, actuators and model-based functions) are increasingly being used for powertrain control, thereby increasing the complexity of such systems. As a consequence the software fine tuning is also becoming more complex leading to increase of costs during the development phase. In this paper is presented theoretical and practical analysis of the OBD system for Otto (L6) and Diesel (L6 / P7) systems in order to evaluate the differences and identify possible synergies between both applications.
Since 2012, adaptive driving beam (ADB) was homologated first in the ECE world (ECE 123). The idea behind is a camera based lighting system, which enables the driver to achieve at night nearly high beam visibility without glaring oncoming or proceeding vehicles and road users. Once the presence of other vehicles is detected the headlamps change the light pattern and block the light where the oncoming or proceeding vehicles are located. Light sources are typically High Intensity Discharge (HID) bulbs, but today also first LED applications are visible. For SAE, the definition of the parameters and the requested regulation changes to allow such systems are in progress. The paper reports about an extensive study executed in Germany at TU Darmstadt to investigate not only the improvement in visibility for the driver with such systems, but also evaluate the disability and discomfort glare for other road users. The results are demonstrating clearly, that the existing ADB systems do not cause additional glare for the road users and also do not lead to an increased subjective discomfort glare rating. The positive effect for the driver in enhancing the visibility at night is significant and improves safety at night time driving.
In today's automotive climate, the tendency of an increasing number of vehicle model variants offered is coming to a head with the growing demands for safer vehicles. New legislation now ensures that the safety improvement by the fitment of stability control systems is certified for each new vehicle. Beginning year 2012, all new cars to be sold in the European Union have to be equipped with ESC, and as means to test performance, a new supplement to ECE R13 requires that the Sine-with-Dwell test be passed. As a result, OEMs have to handle the task of demonstrating that all their vehicles meet homologation requirements. With such a range of variants possible in each model, this can lead to an enormous quantity of testing. However, for the first time, ECE R13 allows homologation to be undertaken by test-supported simulation, and it is now possible to transfer more and more of this work into CAE. This paper describes the results of a project executed at General Motors Europe (GME) in cooperation with Applus IDIADA to prove, document and ensure that it is possible to simulate the Sine-with-Dwell test as the base for ESC certification. Based on extensive static and dynamic tests the validity of a vehicle model together with a brake controller and hydraulic model are demonstrated. With several steps of model correlation it is ensured that all model components are understood in detail, so that it is possible to vary model parameters maintaining the validity. Thus, it is possible to cover the complete range of vehicle variants.
Industry standards and practices define a number of mathematical and physical methods to estimate the cargo carrying volume capacity of a vehicle. While some have roots dating back decades, others try to assess the utility of the space for cargo by subjective measurements. Each these methods have their own inherent merits and deficiencies. The purpose of this paper is to highlight the differences in calculated cargo volume amongst the following practices: Society of Automobile Engineers (SAE) J1100[1] International Organization for Standardization (ISO 3832)[2], Global Car manufacturer's Information Exchange group (GCIE)[3], Consumer Reports[4]. This paper provides a method and associated rationale for constructing a new cargo volume calculation practice that attempts to harmonize these procedures into a more contiguous practice. This homologation will benefit publishing industry, vehicle manufacturers and customers alike. The publishing industry would have a common cargo reporting practice to more accurately inform their readers, reducing proliferation of conflicting reports of cargo volumes. Manufacturers could in turn, optimize their products to a single standard rather than sub-optimizing them to many different ones. The customer benefits from a common measuring and reporting system that would readily allow them to more accurately compare the cargo volumes of different manufacturers' vehicles.
The paper addresses the problem of toxic emission from non-road vehicles. The paper presents the results of the investigations and analyses related to the engine operating conditions of a selected group of non-road vehicles. The presented tests have been carried out on a large groups of vehicles - several from each representative group. This was chiefly on-site construction machinery (dump tracks, excavators, bulldozers) used in the construction of the motorway and as an auxiliary equipment in an open-cast mine. An analysis has been performed based on which a range of the most frequently used loads and engine speeds was determined. The obtained time density characteristics (distribution of speeds and loads in time) of the engines was compared to the measuring points of the toxic emission homologation cycle. On this basis conclusions have been drawn in relation to the correlation between the measuring points of the cycle and the most frequently used areas of loads and speeds of different non-road vehicles. From the presented data it results that the currently applicable stationary homologation cycle does not fully reflect the areas of the most frequently used engine speeds and loads Further suggestions for the investigations and analyses have also been made in relation to the issue at hand. Besides, based on the obtained results certain proposals have been formed for further development of the non-road vehicles emission legislation.
Since the late 19th century until recently several electric vehicles have been designed, manufactured and used throughout the world. Some were just prototypes, others were concept cars, others were just special purpose vehicles and lately, a considerable number of general purpose cars has been produced and commercialized. Since the mid nineties the transportation sector emissions are being increasingly regulated and the dependency on oil and its price fluctuations originated an increasing interest on electric vehicles (EV). A wide research was made on existing electric/hybrid vehicle models. Some of these vehicles were just in the design phase, but most reached the prototype or full market production. They were divided into several types, such as NEVs, prototypes, concept cars, and full homologated production cars. For each type of vehicle model a technical historic analysis was made. Data related to the vehicle configuration as well as the embedded systems were collected and compared. Based on these data future prospect of evolution was subsequently made. The main focus was put on city vehicles and long range vehicles. For city vehicles the market approach normally consists in the use of full electric configuration while for the latter, the hybrid configuration is commonly used. The electrical systems and combustion engines found in these vehicles are compared in order to forecast the evolution trend in terms of specifications and performance of the whole vehicle and of each system.
This study aims to characterize real world bus driving behavior from data obtained in experimental campaigns using instrumented buses. An integrated statistical method to determine bus driving behavior, based on analysis of time series of bus speed and GPS location data, is illustrated in this paper. Kinematic features of bus operating conditions are characterized by multivariate analysis of trip speed time series. Each trip is analyzed within a multi-level hierarchical structure: sequence, sub-cycle, cycle (part of trip between two successive bus stops). Finally, a preliminary application of the proposed method is shown, based on data obtained with buses of different size and homologation class in Naples and Palermo. Reference driving cycles were built, for one line in both cities, taking the most statistically representative cycles of each line with regard to different traffic and road situations. The ensuing results are useful in evaluating emissions measured in on-road testing at different space and time scales and their association to driving operations.
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