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BMW is using the AS8510, an integrated automotive data acquisition front-end integrated circuit (IC) from ams AG, a leading provider of high performance analog ICs and sensors, to provide extremely accurate battery voltage and current measurements in its i3 electric vehicles (EVs).
The BMW i3 model in volume production today includes an AS8510 in the battery sensor. The battery management system (BMS) monitors battery voltage and battery current of the 400V li-ion battery powering the cars’ electric motors, and ensures the functional safety of the vehicle’s battery systems.
Optimization of energy storage and battery life are essential for EVs in order to provide customers with sufficient range and reliability. Accurate current and voltage measurements enable the BMS to make a highly accurate calculation of a li-ion battery’s State of Charge (SOC). The driver benefits from an accurate estimation of the range the vehicle can cover before the battery is completely discharged.
When backed by a special calibration scheme, the sensor system in the BMS is able to measure current to an accuracy of just ±0.5% and voltage to an accuracy of better than ±0.1% over the full operating temperature range of the AS8510 (-40°C to +125°C) and over life time.
Features of the AS8510 that eased the task of designing the i series’ current and voltage measurement system include its zero-offset architecture, low noise, high linearity, multi-channel architecture and low drift.
The AS8510 provides integrated data acquisition front ends, which include two independent 16-bit sigma-delta ADCs. Measuring current across a shunt resistor in one channel over a range from a few milliamps up to 1kA, it provides a digital output via a serial peripheral interface. Through the second channel it can capture three different voltage sources simultaneously with current samples.
The AS8510 Data Acquisition is tailored to measure accurately battery current from mA range up to kA range in combination with a 100 µOhm shunt resistor connected in series with the battery rail. Through the second measurement channel it enables capture of either battery voltage synchronous with the current or to measure the analog output of an internal or external temperature sensor.
The AS8510 is fully compliant with the AEC-Q100 standard (Automotive Electronics Council stress qualification for integrated circuits). The device supports the functional safety compliance efforts of car manufacturers in line with the requirements of the ISO 26262 standard.
The techniques for monitoring the State Of Charge (SOC) and the State Of Health (SOH) in electric vehicle batteries are constantly being refined and improved, and BMW has set a new benchmark in battery management system design in the new i3 model. ams is proud to have supported BMW’s advanced implementation of ultra-accurate battery parameter measurement in the demanding environment of a vehicle drivetrain.—Bernd Gessner, Vice-President and General Manager of the automotive business unit at ams
Austria-based ams is a leading designer and manufacturer of sensor and analog solutions including light sensor and controller ICs. Its products are aimed at applications which require extreme precision, accuracy, dynamic range, sensitivity, and ultra-low power consumption. ams’ product range includes sensors, sensor interfaces, power management ICs and wireless ICs for customers in the consumer, industrial, medical, mobile communications and automotive markets.
Citroën will unveil its new C4 Cactus AIRFLOW 2L concept at the Paris Motor Show. With the C4 Cactus AIRFLOW 2L concept, Citroën is demonstrating fuel consumption of 2l/100 km (118 mpg US) through the use of optimized design with a 20% improvement in aerodynamics; lower rolling resistance (Tall&Narrow) tires; efforts to use lighter parts and thus reduce overall vehicle weight by 100 kg; and the implementation of Hybrid Air technology (earlier post), which cuts fuel consumption by 30%.
The C4 Cactus AIRFLOW 2L project was conducted as part of the “2l/100 km vehicle” program set up by the Plateforme de la Filière Automobile, an industry group. The objective was to deliver practical solutions to reduce the impact of vehicle running costs, on household expenditure and to reduce the eco-footprint of car travel.
Citroën decided to develop this project on the basis of its new model, C4 Cactus. The production C4 Cactus already ships with a range of features designed to reduce fuel consumption. With the C4 Cactus AIRFLOW 2L concept, Citroën went further.
Hybrid Air. With its latest-generation small engines meeting the future Euro 6 standard, the production Citroën C4 Cactus already ranks among the best in its segment with CO2 emissions from 82 g/km and fuel consumption starting at just 3.1 l/100 km (76 mpg US).
The C4 Cactus AIRFLOW 2L concept goes even further by adopting the Hybrid Air drivetrain. Presented by the PSA Peugeot Citroën Group in January 2013 and at the 2013 Geneva Motor Show on the Citroën C3 (earlier post), this technology combines a range of proven sub-systems and technologies: a 3-cylinder PureTech gasoline engine; a compressed air energy storage unit; a hydraulic pump/motor unit; and an automatic transmission with an epicyclic gear train.
An intelligent electronic management system manages input from the driver to optimize energy efficiency. Three operating modes are available:
Air power (zero emissions) in which the compressed air motor replaces the gasoline combustion engine;
Gasoline power, using only the combustion engine; and
Hybrid power, drawing upon both the combustion engine and the compressed air.
On the C4 Cactus AIRFLOW 2L concept, the two compressed air storage tanks are made of composite materials and positioned at the rear of the vehicle.
The PureTech 82 engine, already available on the production model, has been optimized for this new hybrid drivetrain.
Friction losses, which account for 20% of the power consumed by the engine, have been reduced in several ways: using a Diamond-Like Carbon coating; making moving parts lighter; and using bearings to guide rotating parts. Further improvements were made by adopting new polymer pads and using very low viscosity oil. Combined with efforts to optimise combustion, overall engine efficiency has been improved by 5%.
Combining the PureTech 82 engine with Hybrid Air technology on the C4 Cactus AIRFLOW 2L concept reduces fuel consumption by 30% and contributes significantly to achieving a vehicle of 2l/100 km while approaching the PureTech 110 in terms of dynamic performance.
Body style optimized for aerodynamic performance. The unique design of the Citroën C4 Cactus associates flowing lines with strong graphic features, each one highlighting a function (protection with the Airbumps and wheel arches; transporting objects with the roof arches; light with the glazed panoramic sunroof). On the C4 Cactus AIRFLOW 2L, some styling features have been modified and others created in order to optimize vehicle aerodynamics.
Variable-geometry styling parts:
The new front bumper features three controlled air intakes the openings of which are continuously adjusted in accordance with vehicle use, both for engine cooling and for airflow.
Mobile side deflectors have been added behind the quarter-window to effectively guide the air flow around the vehicle.
The wheels feature mobile shutters activated and controlled by centrifugal force.
Fixed-geometry styling parts:
The tires selected to equip the vehicle are of the new-generation 19" Tall&Narrow type. Their design and “ultra ultra” low rolling resistance characteristics improve both energy efficiency and aerodynamics. Their large diameter also contributes to comfort since they are better able to soak up bumps and dips in the road surface.
The wheel arches feature an “Air Curtain”. Small aerodynamic slats on either end of the front bumper channel the airflow and smooth it out along the wheels.
The spoiler has been lengthened and an air extractor added on the rear bumper in order to effectively channel the airflow around the C4 Cactus AIRFLOW 2L and reduce the turbulence that can increase drag.
The conventional door mirrors have been replaced by smaller, slimmer rearview cameras to reduce impact on air flow.
The vehicle substructure has been entirely streamlined. The air flows smoothly, unhampered by the sub-systems positioned under the car.
LED light modules at front and rear replace the existing lights. Consuming little power, they save energy and thus fuel.
These changes can be recognized by their color and by the materials used. The color orange identifies all the aerodynamic features and underlines the high-tech character of the C4 Cactus AIRFLOW 2L concept.
Lighter weight. The production C4 Cactus is already 200 kg (441 lbs) lighter than the Citroën C4, and the C4 Cactus AIRFLOW 2L concept shaves off a further 100 kg (220 lbs), including the drivetrain. These efforts have therefore reduced the weight of the concept by 11% compared with the production vehicle.
Efforts to reduce the weight of structural parts on the C4 Cactus AIRFLOW 2L concept entailed the use of new materials in the body substructure:
aluminium, in particular, for the upper cowl panel, inner side members and rear floor pan;
high-yield steels for the front side rails and heel board; and
composite materials for the front floor.
This multi-material substructure made it necessary to develop special assembly techniques never used before in the automotive industry. Composite structural parts are a promising field of exploration and will certainly be essential to efforts to make cars lighter in the future. The large-scale production of these parts is one of the high-tech, industrial challenges to be addressed by the automotive sector, Citroën noted.
Beyond structural parts, extensive studies were conducted on all vehicle parts to reduce the weight of the C4 Cactus AIRFLOW 2L concept. Emphasis was placed on lightweight, high-performance materials:
Carbon-based composite materials were used for the suspension springs, tailgate, rear bench, side panels, roof, roof cross-members, wings and doors. On the lower side sill, wheel arches and lower part of the front bumper, the “textured” look of the carbon brings out the matt appearance of these parts, providing an attractive contrast with the pearlescent appearance of surrounding features.
Aluminium is used for the engine cradle. The bonnet specifications were the same as for the production C4 Cactus, which already used aluminium.
Owing to their significantly lower bulk density (around 2,700 kg/m3 for aluminium and around 1,200 kg/m3 for carbon compared with 7,800 kg/m3 for steel), these materials contribute significantly to reducing overall vehicle weight.
Given that every gram is important, Citroën also decided to use:
New processes to reduce the thickness of the tubes and cups of the exhaust line and thus reduce weight.
Translucent polycarbonate for the panoramic sunroof. This material is even lighter than multi-layer glass but has the same properties in terms of thermal and acoustic insulation and ultraviolet filtering capability.
Carbon fibres on the Airbumps to make the material lighter while maintaining its technical properties
DuPont Industrial Biosciences (DuPont) has selected Murex LLC to market the cellulosic ethanol produced from its 30-million-gallon-per-year plant in Nevada, Iowa. (Earlier post.) Upon completion, the facility will be the largest cellulosic ethanol plant in the world.
DuPont has made substantial investments in renewable fuels and has committed more than $200 million to the Nevada biorefinery, which will utilize corn stover.
DuPont began developing an integrated solution for the commercial scale production of second generation ethanol from biomass in 2008. At its demonstration facility in Vonore, Tennessee, it combined expertise in biorefinery design with an optimized technology package of novel enzymes and fermentation organisms, resulting in:
Demonstrating lower-capital integrated unit operations;
Achieving economic and environmental targets; and
Producing stover-based ethanol used in many vehicles at the University of Tennessee.
This optimized conversion process is being deployed in the facility in Nevada, Iowa.
In addition to Murex’s strong presence in the domestic ethanol market, the company has been the largest exporter of domestically produced ethanol since 2010. Murex was one of the first marketers of advanced Renewable Identification Numbers (RINs) and developed an in-house due diligence program prior to the Quality Assurance Program that allows smaller producers of advanced RINs to deliver their products and RINs to market.
MAHLE has developed a piston ring with new technology that offers engine manufacturers improvements in weight, quality and overall value. MAHLE’s new “second” piston ring uses chrome-silicon steel to replace cast iron traditionally used for the second of three rings found on gasoline-powered spark-ignition engines. MAHLE’s thinner, lighter-weight steel-wire design for the second ring is based on the company’s own NanoNapier Steel (NNS) technology for which a patent is pending.
Conventionally, there are two types of piston rings: compression and oil control. A piston assembly includes one or more compression rings that generate a seal between the outer surface of the piston and the wall of the cylinder to prevent high-pressure combustion gases and air from escaping the combustion chamber. Today’s engines have three piston rings: two compression rings: top (or first) and second and the oil control ring. The second ring is known as a Napier ring.
In addition to sealing off the combustion chamber, piston rings also dissipate the heat that arises in the piston to the cylinder surface and control the oil balance. As temperatures, pressures, and rotational speeds continue to rise, piston rings are subjected to ever increasing loads.
Too, the second piston ring also may perform an oil scraping function, which entails scraping oil from the cylinder wall on the downward stroke of the piston.
The Napier-style ring includes a generally tapered outer peripheral face and a lower surface having a hook groove. Some second piston rings are produced from metallic wire that is subsequently machined to the desired cross-section.
In its patent applications, MAHLE notes that:
The machining processes may include turning and grinding, which is a costly and time consuming step to providing the desired shape. The machining process also results in burrs and chips from turning or grinding of the material, which results in waste and fine particles that need to be cleaned from the wire prior to use, which is a problem. Known designs have attempted to alleviate these problems by using cast iron second rings, rather than steel from drawn/rolled wires, as cast iron is easier to machine and therefore results in less machining costs and fewer burrs. However, the use of steel wire in second rings is desirable because of its relative lightness and durability when compared to cast iron, and thus a means of reducing machining processes required for forming a steel wire second ring is desirable.
Additionally, previous designs incorporating the Napier-style profile for use in a steel wire second ring required multiple machining operations. The need for multiple grinding steps using a plurality of grinding surfaces results from the need for a generally sharp edge that is required to increase the scrapping effect of the second ring. However, typically drawn/rolled wire cannot generally be formed with sufficiently sharp-edged profiles (generally, corners in profiles of drawn/rolled wire have a rounded shape with a minimum radius of 0.05 mm). Thus, multiple grinding operations to sharpen the edge are required.
More specifically, a first grinding operation must be applied to a bottom surface of the ring, and a second grinding operation must be applied to the outer diameter surface. The standard Napier hook includes an axial offset, which prevents the underside of the hook from being contacted with a single grinding surface, e.g., during a lower surface grinding operation. Thus, at least a second grinding operation is typically required along the outside diameter (O.D.) surface in order to form the relatively sharp edge (in addition to the necessary lower surface grinding operation). Previous micro-Napier type designs similarly include an axial offset, which completely prevents any contact by the grinding surface during application to the lower surface to the outer edge.—US 20130154196
In short, MAHLE has designed a method for constructing an improved Napier-style ring from steel wire.
Rings made from cast iron are heavier and require a considerable amount of machining. Cast iron simply is no longer suitable for most current and next-generation engine applications.—Steven Sytsma, a piston-ring product expert at MAHLE
Cast iron for decades has been the material of choice for the second piston ring because of its wear characteristics and compatibility with other engine-design features. The trend to higher revving, lower-friction engines, however, has resulted in the need to reduce ring size and weight as axial piston heights (distance between a piston’s top and bottom) have dropped.
Sytsma notes that over the past 20 years ring height has decreased by 40% or more—from 2.0 mm to 1.2 mm or less—causing MAHLE to look for cast-iron replacement materials.
MAHLE began development of a first-generation second ring with steel in 2010 using a steel-wire design. The company’s engineers relied on proven suppliers to deliver wire that met MAHLE’s demanding product requirements. The new steel rings have fewer material defects and improved quality overall which in turn provides significantly better customer value.
Benefits of MAHLE’s NNS second-ring include the elimination of foundry-related defects, reduced engine-oil consumption and substantial face- and side-wear resistance. In addition, the thinner axial height and radial thickness provided by the new design has the potential to help make pistons even lighter and engines more capable of operating with less vibration and friction at higher rpms.
Because a NNS second ring is axially and radially smaller, it also has less mass and is dynamically more efficient at its dual tasks of both sealing off oil from the upper portion of the piston chamber and regulating gas pressure within the piston ring belt. Engineers will be able to take advantage of thinner second rings to further reduce weight as well.
MAHLE currently supplies top, second and third rings to vehicle OEMs, engine manufacturers and piston suppliers around the world. Several years ago MAHLE replaced cast iron with steel for its top rings.
Customer interest in our new NanoNapier Steel ring has been exceptionally strong. Production of the new ring for a major original equipment customer will begin later this year at a MAHLE facility in St. John’s, Michigan, and we are actively pursuing contracts for more than 20 additional programs with multiple customers as well.—Scott Ferriman, MAHLE’s vice president for North American sales
Ferriman adds that the company currently is quoting on business with annual production volumes of 15 million NNS rings or more.
Piston ring formed from ring blank US 20130154196
ArcelorMittal, the world’s largest steel and mining company, has created two sets of steel solutions to reduce the average weight of pick-ups, following on from the award-winning launch of its S-in motion catalogue for standard, C-segment cars. ArcelorMittal has refined and extended these innovations to help meet the specific challenges facing the North American light truck market.
The first set uses currently available advanced high strength steels and press-hardenable steel grades such as Usibor 1500 and Ductibor 500 and can reduce weight by up to 174 kg (384 lbs) or 23% of the combined weight of a pick-up’s cab, box, frame and closures, compared with a modern (2014) baseline vehicle.
Reducing the average weight of pick-ups by this amount saves more than 14 grams of CO2-equivalent emissions per kilometer, helping pick-up trucks meet regulatory standards in the EU and US. The second uses emerging grades which are in the final stages of development.
ArcelorMittal says that S-in motion Steel PickUp meets OEMs’ acceptance criteria and has been validated for all major automotive standards, including crash safety and stiffness requirements.
The new steel solutions include advanced steel grades developed by ArcelorMittal’s research and development (R&D) teams in Maizières-lès-Metz and Montataire, France and East Chicago, Indiana.
Pick-up trucks represent a significant part of the NAFTA region’s light vehicle market. According to IHS, more than 2.6 million body-on-frame light pick-up trucks will be produced in the NAFTA region this year.
The launch follows significant investment by ArcelorMittal in automotive research and development, which accounts for 33% of the total global budget of US$270 million.
The original S-in motion includes multiple solutions for 63 parts of a typical C-segment vehicle and offers weight savings of up to 22% for a car chassis, and a 6.23 g drop in CO2 emissions per kilometer, in a car using the lightest S-in motion solutions. The S-in motion solutions use a range of:
Press hardened steels (PHS) amounting to 25% of the BIW and crash management system (CMS);
Advanced high strength steels (AHSS) for around 29% of the BIW and CMS;
Stainless steel (typically 17.7C-1.4310 for the A-pillar lower outer); and
Long products such as forged SOLAMB1100 for the steering knuckle.
On 23 September 2014, Ivan Viaux, Research Engineer at ArcelorMittal Global R&D, will explain at the Aachen Body Engineering Days 2014 conference how ArcelorMittal steels can help carmakers to reduce the weight of their plugged-in hybrid electrical vehicles (PHEV) without additional cost through the PHEV S-in motion project.
The PHEV S-in motion project’s main objective is to identify the challenges to convert one internal combustion engine (ICE) vehicle to an PHEV and study the relevancy of weight savings potential of advanced high strength steel (AHSS) on PHEV vehicle architecture. Ivan Viaux will highlight how AHSS combined with innovative body-in-white design and relevant process approaches can help to achieve weight savings without cost penalty despite heavier powertrains.
Over the past decade, advanced high strength steels have become the fastest growing material for light vehicle construction. ArcelorMittal Europe’s shipments of these steels have doubled in the last five years, to account for one quarter of ArcelorMittal Europe’s total automotive steel shipments. For the NAFTA region, ArcelorMittal’s order book for advanced high strength steels (including press hardenable steels) is expected to rise from 20% of total automotive steel orders today to 35% in 2019.
ArcelorMittal is continuously working on new steel grades in order to meet manufacturers’ needs for the automotive industry. At any one time, up to 80 new grades are under development, with researchers working with OEMs many years in advance in order to develop ever-more efficient, safer and lighter vehicles for the future.
Diu is now home to India’s first dedicated world-class cycle track. “We are proud of having successfully created such a world-class cycling infrastructure in Diu. The dedicated cycle tracks will give a great boost to tourism and the city environment. Our objective is to transform Diu as an ecologically conscious tourist destination, and the dedicated cycle tracks are a significant step towards promoting green, environmentally-friendly commuting. The aim is clear: to make Diu the cycling destination of India", said Bhupinder S Bhalla, administrator of the Daman and Diu, the second smallest union territory on India’s west coast.
Bhalla stated that, “The dedicated cycle tracks are part of green initiatives to preserve ecology and promote environmentally-friendly tourism with the use of bicycles as a means of transport. We have also planned for a cycle rally to promote the message of environment friendliness, fitness consciousness, besides tourism and safeguarding the fragile environment by promoting non fossil-fuel based transport in the city.” As part of its ecotourism initiative, the former Portuguese colony had a cycle rally on August 4 that welcomed over 300 enthusiastic cyclists. Bhalla told The Pioneer: “Of the 11.3-km dedicated track, already 4.2-km of track has been completed. The Rs 37-crore ($6 million) project will cover the entire tiny island, which attracts a large number of foreign and domestic tourists.” According to Bhalla, Silvassa and Daman are likely to implement similar projects.
Supported by the Centre for Green Mobility (CGM), based in Gujarat, the dedicated track is likely to draw tourists to this beautiful port in the Saurashtrian region in Gujarat. “The tracks have been designed keeping the national safety standards in mind so that cyclists are provided a safe, dedicated track that is separated from the main flow of traffic. Safety of tourists and citizens is a prime concern and therefore all the junctions will have cycle priority signals and a design that prioritises cyclists and pedestrians over other motorised modes", said the CGM executive director, Anuj Malhotra.
Dedicated cycle lanes will go a long way in protecting the fragile and sensitive ecosystem—its balance being increasingly tipped by the rapidly growing human population and the vagaries that come with it. Cycling is perhaps the most environmentally-friendly mode of transport. India’s alarmingly populous capital city, Delhi, is mulling the construction of cycle lanes to combat issues of blatant, uncontrollable pollution and traffic congestion on arterial roads. "All committee members have arrived at a consensus that special lanes will be created for non-motorised vehicles on as many roads as possible", said Rakesh Mehta, Delhi’s chief secretary. In Gurgaon (Harayana), a key business district, the construction of 22 km of dedicated cycling lanes has been proposed by the municipal corporation. IT-capital Bangalore’s Department of Urban Land Transport will continue to construct more cycle lanes in heavy-traffic areas despite the failure of cycle lanes in the suburb of Jayanagar.
It would do India a world of good if its densely populated cities would rediscover cycling — an effective weapon against fuel costs that are continually hiked, irreparable damage to the environment from motorised vehicles, hours of commuting time and decline in human health. With so many cities actively promoting the use of cycles, India has to recognise that advocating cycling lanes will take it closer to the goal of achieving sustainable mobility.