Category Archives: Automotive

Manufacturing System

A flexible manufacturing system (FMS) is a manufacturing system in which there is some amount of flexibility that allows the system to react in case of changes, whether predicted or unpredicted. This flexibility is generally considered to fall into two categories, which both contain numerous subcategories. The first category, machine flexibility, covers the system’s ability to be changed to produce new product types, and ability to change the order of operations executed on a part. The second category is called routing flexibility, which consists of the ability to use multiple machines to perform the same operation on a part, as well as the system’s ability to absorb large-scale changes, such as in volume, capacity, or capability.

Most FMS consist of three main systems. The work machines which are often automated CNC machines are connected by a material handling system to optimize parts flow and the central control computer which controls material movements and machine flow. The main advantages of an FMS is its high flexibility in managing manufacturing resources like time and effort in order to manufacture a new product. The best application of an FMS is found in the production of small sets of products like those from a mass production.

An Industrial Flexible Manufacturing System (FMS) consists of robots, Computer-controlled Machines, Numerical controlled machines (CNC), instrumentation devices, computers, sensors, and other stand alone systems such as inspection machines. The use of robots in the production segment of manufacturing industries promises a variety of benefits ranging from high utilization to high volume of productivity. Each Robotic cell or node will be located along a material handling system such as a conveyor or automatic guided vehicle. The production of each part or work-piece will require a different combination of manufacturing nodes. The movement of parts from one node to another is done through the material handling system. At the end of part processing, the finished parts will be routed to an automatic inspection node, and subsequently unloaded from the Flexible Manufacturing System.

The FMS data traffic consists of large files and short messages, and mostly come from nodes, devices and instruments. The message size ranges between a few bytes to several hundreds of bytes. Executive software and other data, for example, are files with a large size, while messages for machining data, instrument to instrument communications, status monitoring, and data reporting are transmitted in small size. There is also some variation on response time. Large program files from a main computer usually take about 60 seconds to be down loaded into each instrument or node at the beginning of FMS operation. Messages for instrument data need to be sent in a periodic time with deterministic time delay. Other types of messages used for emergency reporting are quite short in size and must be transmitted and received with an almost instantaneous response. The demands for reliable FMS protocol that support all the FMS data characteristics are now urgent. The existing IEEE standard protocols do not fully satisfy the real time communication requirements in this environment. The delay of CSMA/CD is unbounded as the number of nodes increases due to the message collisions. Token Bus has a deterministic message delay, but it does not support prioritized access scheme which is needed in FMS communications. Token Ring provides prioritized access and has a low message delay, however, its data transmission is unreliable. A single node failure which may occur quite often in FMS causes transmission errors of passing message in that node. In addition, the topology of Token Ring results in high wiring installation and cost.

A design of FMS communication that supports a real time communication with bounded message delay and reacts promptly to any emergency signal is needed. Because of machine failure and malfunction due to heat, dust, and electromagnetic interference is common, a prioritized mechanism and immediate transmission of emergency messages are needed so that a suitable recovery procedure can be applied. A modification of standard Token Bus to implement a prioritized access scheme was proposed to allow transmission of short and periodic messages with a low delay compared to the one for long messages.

Manufacturing System can be defined as the process involved in the production of merchandise using machines, tools, labour which may be intended for use or sale. It is the method of organizing production.
Manufacturing takes turns under all types of economic systems. In a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more frequently directed by the state to supply a centrally planned economy. In mixed market economies, manufacturing occurs under some degree of government regulation.

Related Journals of Manufacturing System:
Journal of Material Sciences & Engineering, Advances in Automobile Engineering, Journal of Aeronautics & Aerospace Engineering, Journal of Applied Mechanical Engineering, Journal of Manufacturing Processes, Manufacturing Letters, Journal of Manufacturing Systems, Journal of Advanced Manufacturing Systems, International Journal of Mechatronics and Manufacturing Systems

High Performance EMC

C P Wong is the Charles Smithgall Institute Endowed Chair and Regents’ Professor at Georgia Institute of Technology, and Dean of Engineering at the Chinese University of Hong Kong. He received his primary and secondary education in Hong Kong and furthered his education in the US. He received his BS degree from Purdue University, and PhD degree from the Pennsylvania State University. He received many awards, among those, the AT&T Bell Labs Fellow Award in 1992, the IEEE CPMT Society Outstanding Sustained Technical Contributions Award in 1995, the Georgia Tech Sigma Xi Faculty Best Research Paper Award in 1999, Best MS, PhD and Undergraduate Thesis Awards in 2002 and 2004, respectively, the University Press (London) Award of Excellence, the IEEE Third Millennium Medal in 2000. His research interests lie in the fields of polymeric materials, electronic packaging and interconnect, interfacial adhesions, nano-functional material syntheses, Si etching and energy storage. His work includes nano-composites such as well-aligned carbon nanotubes, graphenes, lead-free alloys, flip chip underfill, ultra high k capacitor composites superhydrophobic coatings and supercapacitors. He holds over 65 US patents, numerous international patents, has published over 1000 technical papers, 12 books. He is a Member of the National Academy of Engineering of the USA since 2000, and a Foreign Academician of the Chinese Academy of Engineering 2013.

As the number of electronic components in automobiles increases, the electronic industry has seen an increasing need for organic packaging materials that meet property requirements for long cycling operations under harsh environments. Of the many materials involved in a package, epoxy-based molding compound (EMC) is the outermost encapsulation, and it is essential for the molding material to offer high temperature durability. Research has shown that the adverse effects of thermal aging on EMC can be attributed to temperature-induced shrinkage and oxidation. EMCs currently on the market use multiaromatic structure in the resin to add thermal stability to the cured composite, but still show undesirable changes in material properties at temperatures above ~175°C, where resin decompositions and loss of volatile species are observed. For improved thermal stability, it is desirable for EMCs to have high glass transition temperature. We enhance the resin crosslinking and thermal resistance by utilizing the superior heat resistance of the epoxy-triazine copolymer in the curing system. In this case, the highly aromatic epoxy matrix increases the EMC’s Tg, and the s-triazine moiety further enhances high temperature stability the EMC. In this talk, we will show preliminary results on the incorporation of s-triazine into EMC and the thermal stability improvements that results.

Automotive electronics are electronic systems used in road vehicles, such as: engine management, ignition, radio, carputers, telematics, in-car entertainment systems and others. Electronic systems have become an increasingly large component of the cost of an automobile, from only around 1% of its value in 1950 to around 30% in 2010. The earliest electronics systems available as factory installations were vacuum tube car radios, starting in the early 1930’s. The development of semiconductors after WWII greatly expanded the use of electronics in automobiles, with solid-state diodes making the automotive alternator the standard after about 1960, and the first transistorized ignition systems appearing about 1955.

The availability of microprocessors after about 1974 made another range of automotive applications economically feasible. In 1978 the Cadillac Seville introduced a “trip computer” based on a 6802 microprocessor. Electronically-controlled ignition and fuel injection systems allowed automotive designers to achieve vehicles meeting requirements for fuel economy and lower emissions, while still maintaining high levels of performance and convenience for drivers. Today’s automobiles contain a dozen or more processors, in functions such as engine management, transmission control, climate control,antilock braking, passive safety systems, navigation, and other functions. Modern electric cars rely on power electronics for the main propulsion motor control, as well as managing the battery system. Future autonomous cars will rely on powerful computer systems, an array of sensors, networking, and satellite navigation, all of which will require electronics.

Design of Composite Leaf Spring

Reducing weight while increasing or maintaining strength of products is getting to be highly important research issue in this modern world. The suspension system in a vehicle significantly affects the behavior of vehicle i.e., vibration characteristics including ride comfort, stability etc. Leaf springs are commonly used in the vehicle suspension system and are subjected to millions of varying stress cycles leading to fatigue failure. A lot of research has been done for improving the performance of leaf spring. Now the automobile industry has shown interest in the replacement of steel spring with composite leaf spring. In general, it is found that fiberglass material has better strength characteristic and lighter in weight as compare to steel for leaf spring. In this research work the author has reviewed some papers on the design and analysis leaf spring performance and fatigue life prediction of leaf spring. There is also the analysis of failure in leaf spring. The automakers can reduce product development cost and time while improving the safety, comfort and durability of the vehicles they produce. The predictive capability of CAE tools has progressed to the point where much of the design verification is now done using computer simulation rather than physical prototype testing.

Basic vehicle maintenance is a fundamental part of a mechanic’s work in modern industrialized countries while in others they are only consulted when a vehicle is already showing signs of malfunction. Preventative maintenance is also a fundamental part of a mechanic’s job, but this is not possible in the case of vehicles that are not regularly maintained by a mechanic. One misunderstood aspect of preventative maintenance is scheduled replacement of various parts, which occurs before failure to avoid far more expensive damage. Because this means that parts are replaced before any problem is observed, many vehicle owners will not understand why the expense is necessary.

With the rapid advancement in technology, the mechanic’s job has evolved from purely mechanical, to include electronic technology. Because vehicles today possess complex computer and electronic systems, mechanics need to have a broader base of knowledge than in the past. A mechanic usually works from the workshop in which the (well equipped) mechanic has access to a vehicle lift to access areas that are difficult to reach when the car is on the ground. Beside the workshop bound mechanic, there are mobile mechanics like those of the UK Automobile Association (the AA) which allow the car owner to receive assistance without the car necessarily having to be brought to a garage.

A mechanic may opt to engage in other careers related to his or her field. Teaching of automotive trade courses, for example, is almost entirely carried out by qualified mechanics in many countries. There are several other trade qualifications for working on motor vehicles, including panel beaterspray painterbody builder and motorcycle mechanic. In most developed countries, these are separate trade courses, but a qualified tradesperson from one can change to working as another. This usually requires that they work under another tradesperson in much the same way as an apprentice.

Auto body repair involves less work with oily and greasy parts of vehicles, but involves exposure to particulate dust from sanding bodywork and potentially toxic chemical fumes from paint and related products. Salespeople and dealers often also need to acquire an in-depth knowledge of cars, and some mechanics are successful in these roles because of their knowledge. Auto mechanics also need to stay updated with all the leading car companies as well as new launching cars. One has to study continuously on new technology engines and their work systems.

Pit crews for motor racing are a specialized form of work undertaken by some mechanics. It is sometimes portrayed as glamorous in movies and television and is considered prestigious in some parts of the automotive industry. Working in a pit crew in professional racing circuits is potentially dangerous and very stressful work due to the tight margins for error, and the potential financial losses and gains by the racing teams, but a pit crew mechanics pay is usually high to reflect the extra skill/stress levels

Automotive Engineering

Automobile engineering, along with aerospace engineering and marine engineering, is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles and trucks and their respective engineering subsystems. It also includes modification of vehicles. Manufacturing domain deals with the creation and assembling the whole parts of automobiles is also included in it.The automotive engineering field is research -intensive and involves direct application of mathematical models and formulas. The study of automotive engineering is to design, develop, fabricate, and testing vehicles or vehicle components from the concept stage to production stage. Production, development, and manufacturing are the three major functions in this field.

Automobile Engineering is mainly divided into three streams such as production or design engineering focuses on design components, testing of parts, coordinating tests, and system of a vehicle.

Automobile Engineering

Automobile Engineering is a branch study of engineering which teaches manufacturing, designing, mechanical mechanisms as well operations of automobiles. It is an introduction to vehicle engineering which deals with motorcycles, cars, buses trucks etc. It includes branch study of mechanical, electronic, software and safety elements. Some of the engineering attributes and disciplines that are of importance to the automotive engineer and many of the other aspects are included in it:

Safety engineering: Safety engineering is the assessment of various crash scenarios and their impact on the vehicle occupants. These are tested against very stringent governmental regulations. Some of these requirements include: seat belt and air bag functionality testing, front and side impact testing, and tests of rollover resistance. Assessments are done with various methods and tools, including Computer crash simulation (typically finite element analysis), crash test dummies, and partial system sled and full vehicle crashes.

Fuel economy/emissions: Fuel economy is the measured fuel efficiency of the vehicle in miles per gallon or kilometers per liter. Emissions testing includes the measurement of vehicle emissions, including hydrocarbons, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), and evaporative emissions.

Vehicle dynamics: Vehicle dynamics is the vehicle’s response of the following attributes: ride, handling, steering, braking, comfort and traction. The design of the chassis systems of suspension, steering, braking, structure (frame), wheels and tires, and traction control are highly leveraged by the vehicle dynamics engineer to deliver the vehicle dynamics qualities desired.

NVH engineering (noise, vibration, and harshness): NVH is the customer’s feedback (both tactile [felt] and audible [heard]) from the vehicle. While sound can be interpreted as a rattle, squeal, or hot, a tactile response can be seat vibration or a buzz in the steering wheel. This feedback is generated by components either rubbing, vibrating, or rotating. NVH response can be classified in various ways: powertrain NVH, road noise, wind noise, component noise, and squeak and rattle. Note, there are both good and bad NVH qualities. The NVH engineer works to either eliminate bad NVH or change the “bad NVH” too good (i.e., exhaust tones).

Vehicle Electronics: Automotive electronics is an increasingly important aspect of automotive engineering. Modern vehicles employ dozens of electronic systems.[1] These systems are responsible for operational controls such as the throttle, brake and steering controls; as well as many comfort and convenience systems such as the HVAC, infotainment, and lighting systems. It would not be possible for automobiles to meet modern safety and fuel economy requirements without electronic controls.

Performance: Performance is a measurable and testable value of a vehicle’s ability to perform in various conditions. Performance can be considered in a wide variety of tasks, but it’s generally associated with how quickly a car can accelerate (e.g. standing start 1/4 mile elapsed time, 0–60 mph, etc.), its top speed, how short and quickly a car can come to a complete stop from a set speed (e.g. 70-0 mph), how much g-force a car can generate without losing grip, recorded lap times, cornering speed, brake fade, etc. Performance can also reflect the amount of control in inclement weather (snow, ice, rain).

Shift quality: Shift quality is the driver’s perception of the vehicle to an automatic transmission shift event. This is influenced by the powertrain (engine, transmission), and the vehicle (driveline, suspension, engine and powertrain mounts, etc.) Shift feel is both a tactile (felt) and audible (heard) response of the vehicle. Shift quality is experienced as various events: Transmission shifts are felt as an upshift at acceleration (1–2), or a downshift maneuver in passing (4–2). Shift engagements of the vehicle are also evaluated, as in Park to Reverse, etc.

Durability / corrosion engineering: Durability and corrosion engineering is the evaluation testing of a vehicle for its useful life. Tests include mileage accumulation, severe driving conditions, and corrosive salt baths.

Package / ergonomics engineering: Package engineering is a discipline that designs/analyzes the occupant accommodations (seat roominess), ingress/egress to the vehicle, and the driver’s field of vision (gauges and windows). The packaging engineer is also responsible for other areas of the vehicle like the engine compartment, and the component to component placement. Ergonomics is the discipline that assesses the occupant’s access to the steering wheel, pedals, and other driver/passenger controls.

Climate control: Climate control is the customer’s impression of the cabin environment and level of comfort related to the temperature and humidity. From the windshield defrosting to the heating and cooling capacity, all vehicle seating positions are evaluated to a certain level of comfort.

Drivability: Drivability is the vehicle’s response to general driving conditions. Cold starts and stalls, RPM dips, idle response, launch hesitations and stumbles, and performance levels.

Cost: The cost of a vehicle program is typically split into the effect on the variable cost of the vehicle, and the up-front tooling and fixed costs associated with developing the vehicle. There are also costs associated with warranty reductions and marketing.

Program timing: To some extent programs are timed with respect to the market, and also to the production schedules of the assembly plants. Any new part in the design must support the development and manufacturing schedule of the model.

Assembly feasibility: It is easy to design a module that is hard to assemble, either resulting in damaged units or poor tolerances. The skilled product development engineer works with the assembly/manufacturing engineers so that the resulting design is easy and cheap to make and assemble, as well as delivering appropriate functionality and appearance.

Quality management: Quality control is an important factor within the production process, as high quality is needed to meet customer requirements and to avoid expensive recall campaigns. The complexity of components involved in the production process requires a combination of different tools and techniques for quality control.

Technology Forecast

Transport sector has an important contribution on global carbon emission. In EU, Transport sector is the second most greenhouse gases emitting sector with 24.3%. Therefore, major car manufacturing countries have declared special regulations and objectives in order to decrease these high emission ratios. EU regulation requires fleets to have 95 g CO2/km cap by 2020. US and Japan has also challenging targets. These targets can only be achieved by partial introduction of electric vehicles to fleets. For this reason, most major manufacturers have already introduced their electric vehicle cars, and they have plans to develop further.

The countries have set some objectives to achieve for electric vehicle market. However, in most cases, these objectives are revised when the deadlines come closer. In 2011 US has put an objective of reaching 1 million electric vehicles by 2015. However, the total of all the electric vehicles according to the report of IEA in 2015 is 665,000. The numbers and range is also very different between different research companies. 2020 estimation for market share of electric vehicles changes from 2% to 25% according to different research organizations.

An important reason for such wide range of estimation and discrepancies on achievement of objectives are due to the major bottlenecks for electric vehicle introduction to the market. Main technical road block is the battery technology. A 24 Kwh Li_Ion Battery for around 100 miles range for a compact vehicle, costs around 8,400 $ with a weight of around 200 kgs. Charging time is also much above of that customers are used to for petrol powered vehicles. Another major road block is charging infrastructure and smart grid systems, which is also in a way related to the battery technology.

In order to estimate the future of electric vehicles, it is necessary to estimate future of electric vehicle batteries. In this article an attempt will be made to estimate the future cost and main performance specifications of electric vehicle batteries. Then an estimation regarding the possible sales volumes of electric vehicles could be done in a more reliable manner.

Electric Vehicle (EV) battery technologies is a limiting factor for the wide spread diffusion of electric vehicles. EV battery’s energy density compared to fossil fuels is still very low, thus EV’s have still stringent driving range with voluminous, heavy and high cost batteries. Automotive OEM’s are trying to estimate the future of batteries to do their plans related to electric vehicle manufacturing. This article attempts to estimate the future of EV batteries and mainly that of Li_Ion, Li_S and Li_Air Technologieswhich seem to be the most promising Technologies as of today. The article explains in detail the methodology used, and the results with an estimation of future EV market as a result of the EV battery development time scale.

Estimating the future of a new technology is not an easy task. In the past there has been many examples of gravely wrong technology forecasts. A typical example was the estimation of electronic computers future around 1940’s by some prominent scientists in US and UK. They forecasted that electronic computers would be used by only mathematicians and both countries would need only a few of them. Such problems has increased the interest on the methodology for technology forecasting.

Technology development is a discontinuous process. For this reason, forecasting is to be done with extensive and detailed analysis. Martino in his article in 1987 has classified technology forecasting methods to four “pure types” as extrapolation, leading indicators, causal models, and stochastic methods. In his article of 2003 Martino has investigated recent advances in technology forecasting and also pointed out methodologies like development of scenarios, Delphi and influence of chaos theory.

Delphi is the oldest technology forecasting method developed by RAND technologies at around 1950’s. For Delphi methodology, an expert management group is selected. This group selects the experts’ team on the subject. Prepares the survey questions. Contacts the experts and gets the answers for the survey. Analyses the results, conduct a second iteration and if necessary a third. Then writes the report analyzing the results of the iteration as well. The success of this methodology depends very much on the selection of the experts, and how much they are ready to share the information. The responses of the experts are weighted according to the different criteria and a probabilistic result is obtained.

Extrapolation methodology is an analytical method. Several performance indicators can be taken to develop a model, like performance of the technology level, number of patents, number of articles written etc. in line with the development stage. A model is fitted to the historical data and the projection of that model gives the future projection. Selection of the right extrapolation methodology is very important for the success of the forecast. If a wrong model is selected the results can be misleading. Logistic Pearl and Gompertz are the most commonly used growth curves. Steurer has used Generalized Extreme Value (GEV) which includes Gompertz as a special case and showed that for some data improved the flexibility of S-curve.

Energy Buffer for Electric Vehicles

Battery Electric Vehicles (BEV) is considered as an important mobility option for reducing the dependence of fossil fuels. After almost a decade after the first serial production electric vehicle launched by Tesla the main auto manufacturers have already claimed their plans and readiness for delivering their electric products to customers. The greatest challenge of the BEV is the battery itself, as they face the customers accustomed to the flexibility of oil derivatives usage. Electric batteries offer either high specific energy capacity to cover acceptable mileage or high specific power to follow typical driving discharge/ charge cycle demands, but not both. Hybridization of the energy source is one widespread nowadays solution and a common strategy would be to combine an electric battery with an additional high-power source usually mechanical devices as kinetic energy storage – flywheels (KES), or electrical device – super-capacitors, for example. Based on its utilization in F1 competition KES systems gain popularity and there are signs from automakers for introducing the KES into mass production.

In spite of some claims that KES technology is immature for BEV applications, nowadays power electronics technology allows KES integration in BEV. A two-power level electric driveline for vehicle application with KES utilization as a balancing energy device is investigated in University of Uppsala, Sweden. Four power converters, three AC/DC and one DC/DC, form the both sides of the proposed electric driveline. Obtained results show more than half of the losses are attributed to the function of KES, but authors do not consider battery and traction motor losses.

Overall energy transfer efficiency is a key factor for hybrid vehicles, where more than one energy source are available. There are different algorithms to govern the power split between the alternative power sources [19,20], such as Lagrange Multipliers, Pontryagin’s Minimum Principle, or Dynamic Programming, but they rely on exact description of energy losses in the all components including the energy sources and seeking the optimal solutions requires high computing resources and time.

Local efficiency of the electric components, such as the battery, electric motor/generators and the power electronics are well known. The aims of the presented investigation are description of KES local efficiency and corresponding overall efficiencies of the alternative power branches in a hybrid BEV with KES as functions of current states of the energy sources and the vehicle energy demands. As a result, admissible areas of KES usage can be formulated in advance; a strategy for power split will be formulated based on sources state, and KES impact on the electric battery can be estimated for the created control strategy.

It is considered a hybrid driveline intended for electric vehicle in which Kinetic Energy Storage (KES) is used as an energy buffer for the load levelling over the main energy source – Li-Ion battery. Relations for KES local efficiency are worked out. Overall efficiencies of the parallel power branches are defined, and a control strategy for power split is proposed based on the alternative storage devices State of Charge (SoC). Quantity estimations of KES influence on the battery loading are obtained by evaluation of covered mileage, achievable with a single battery recharge over standard driving cycles, and by expected battery cycle-life prediction.

Electric and hybrid drive lines; Electric battery; Kinetic energy storage; Efficiency; Achievable mileage; Battery exhausting and ageing

Electric Car

An electric car is an automobile that is propelled by one or more electric motors, using electrical energy stored in rechargeable batteries. The first practical electric cars were produced in the 1880s. Electric cars were popular in the late 19th century and early 20th century, until advances in internal combustion engines, electric starters in particular, and mass production of cheaper gasoline vehicles led to a decline in the use of electric drive vehicles.

Since 2008, a renaissance in electric vehicle manufacturing has occurred due to advances in batteries, concerns about increasing oil prices, and the desire to reduce greenhouse gas emissions. Several national and local governments have established tax credits, subsidies, and other incentives to promote the introduction and now adoption in the mass market of new electric vehicles depending on battery size and their all-electric range.

Compared with cars with internal combustion (IC) engines, electric cars are quieter and have no tailpipe emissions. When recharged by low-emission electrical power sources, electric vehicles can reduce greenhouse gas emissions compared to IC engines. Where oil is imported, use of electric vehicles can reduce imports.

Recharging can take a long time and in many places there is a patchy recharging infrastructure. Battery cost limits range and increases purchase cost over IC vehicles, but battery costs are decreasing. Drivers can also sometimes suffer from range anxiety- the fear that the batteries will be depleted before reaching their destination.

Electric cars are a variety of electric vehicle (EV). The term “electric vehicle” refers to any vehicle that uses electric motors for propulsion, while “electric car” generally refers to highway-capable automobiles powered by electricity. Low-speed electric vehicles, classified as neighborhood electric vehicles (NEVs) in the United States, and as electric motorised quadricycles in Europe, are plug-in electric-powered microcars or city cars with limitations in terms of weight, power and maximum speed that are allowed to travel on public roads and city streets up to a certain posted speed limit, which varies by country.

While an electric car’s power source is not explicitly an on-board battery, electric cars with motors powered by other energy sources are generally referred to by a different name: an electric car carrying solar panels to power it is a solar car, and an electric car powered by a gasoline generator is a form of hybrid car. Thus, an electric car that derives its power from an on-board battery pack is a form of battery electric vehicle (BEV). Most often, the term “electric car” is used to refer to battery electric vehicles.

Much of the mileage-related cost of an electric vehicle is depreciation of the battery pack. To calculate the cost per kilometer of an electric vehicle it is therefore necessary to assign a monetary value to the wear incurred on the battery.

The Tesla Roadster’s battery pack is expected to last seven years with typical driving and costs US$12,000 when pre-purchased today. Driving 40 miles (64 km) per day for seven years or 102,200 miles (164,500 km) leads to a battery consumption cost of US$0.1174 per 1 mile (1.6 km) or US$4.70 per 40 miles (64 km).

The cost of charging the battery depends on the cost of electricity. As of November 2012, a Nissan Leaf driving 500 miles (800 km) per week is estimated to cost US$600 per year in charging costs in Illinois, U.S., as compared to US$2,300 per year in fuel costs for an average new car using regular gasoline.

According to Nissan, the operating electricity cost of the Leaf in the UK is 1.75 pence per mile (1.09 p/km) when charging at an off-peak electricity rate, while a conventional petrol-powered car costs more than 10 pence per mile (6.21 p/km). These estimates are based on a national average of British Petrol Economy 7 rates as of January 2012, and assumed 7 hours of charging overnight at the night rate and one hour in the daytime charged at the Tier-2 daytime rate.

Great effort is taken to keep the mass of an electric vehicle as low as possible to improve its range and endurance. However, the weight and bulk of the batteries themselves usually makes an EV heavier than a comparable gasoline vehicle, reducing range and leading to longer braking distances. However, in a collision, the occupants of a heavy vehicle will, on average, suffer fewer and less serious injuries than the occupants of a lighter vehicle; therefore, the additional weight brings safety benefits despite having a negative effect on the car’s performance. They also use up interior space if packaged ineffectively. If stored under the passenger cell, not only is this not the case, they also lower the vehicles’s center of gravity, increasing driving stability, thereby lowering the risk of an accident through loss of control. An accident in a 2,000 lb (900 kg) vehicle will on average cause about 50% more injuries to its occupants than a 3,000 lb (1,400 kg) vehicle. In a single car accident, and for the other car in a two car accident, the increased mass causes an increase in accelerations and hence an increase in the severity of the accident.

Some electric cars use low rolling resistance tires, which typically offer less grip than normal tires. Many electric cars have a small, light and fragile body, though, and therefore offer inadequate safety protection. The Insurance Institute for Highway Safety in America had condemned the use of low speed vehicles and “mini trucks,” referred to as neighborhood electric vehicles (NEVs) when powered by electric motors, on public roads. Mindful of this, several companies (Tesla Motors, BMW, Uniti) have succeeded in keeping the body light, while making it very strong.

F-N-R gearbox with spur-gear differential

A differential is a gear train with three shafts that has the property that the angular velocity of one shaft is the average of the angular velocities of the others, or a fixed multiple of that average. In automobiles and other wheeled vehicles, the differential allows the outer drive wheel to rotate faster than the inner drive wheel during a turn. This is necessary when the vehicle turns, making the wheel that is traveling around the outside of the turning curve roll farther and faster than the other. The average of the rotational speed of the two driving wheels equals the input rotational speed of the drive shaft. An increase in the speed of one wheel is balanced by a decrease in the speed of the other. When used in this way, a differential couples the input shaft (or prop shaft) to the pinion, which in turn runs on the ring gear of the differential. This also works as reduction gearing. On rear wheel drive vehicles the differential may connect to half-shafts inside an axle housing, or drive shafts that connect to the rear driving wheels. Front wheel drive vehicles tend to have the pinion on the end of the main-shaft of the gearbox and the differential is enclosed in the same housing as the gearbox. There are individual drive-shafts to each wheel.

A differential consists of one input, the drive shaft, and two outputs which are the two drive wheels, however the rotation of the drive wheels are coupled to each other by their connection to the roadway. Under normal conditions, with small tire slip, the ratio of the speeds of the two driving wheels is defined by the ratio of the radii of the paths around which the two wheels are rolling, which in turn is determined by the track-width of the vehicle (the distance between the driving wheels) and the radius of the turn. Non-automotive uses of differentials include performing analog arithmetic. Two of the differential’s three shafts are made to rotate through angles that represent (are proportional to) two numbers, and the angle of the third shaft’s rotation represents the sum or difference of the two input numbers. The earliest known use of a differential gear is in the Antikythera mechanism, circa 80 BCE, which used a differential gear to control a small sphere representing the moon from the difference between the sun and moon position pointers. The ball was painted black and white in hemispheres, and graphically showed the phase of the moon at a particular point in time. See also the Chinese South-pointing chariot. An equation clock that used a differential for addition was made in 1720. In the 20th Century, large assemblies of many differentials were used as analog computers, calculating, for example, the direction in which a gun should be aimed. However, the development of electronic digital computers has made these uses of differentials obsolete. Military uses may still exist, for example, for a hypothetical computer designed to survive an electromagnetic pulse. Practically all the differentials that are now made are used in automobiles and similar vehicles.

Power transmission is an inevitable part in any automobile. The power from the prime mover (engine/motor) is transferred to the wheels using a suitable transmission system. Various designs of gearbox have been developed in the past. In this paper, an F-N-R (forward-neutral-reverse) gearbox with a compact spur-gear differential is designed by following the design parameters for spur gear, for the required output torque of a vehicle. All the gears and casing for the gearbox is modeled using Solidworks tool. A simple and user-friendly shifting mechanism is designed for the gearbox, adding to comfort. A new spur-gear differential is designed, having spur gears to accomplish differential action, which is more compact and light-weight compared to a conventional differential, since the heavy bevel gear assembly is omitted. Different analyses such as static, dynamic (time-dependent), contact, modal and fatigue analyses are done using ANSYS software. The main objective is to design and fabricate a light-weight, efficient and compact F-N-R gearbox as a replacement to current models.

In this study, an in-wheel motor torque control strategy was proposed for a 4-wheel drive in-wheel type electric vehicle by considering the rollover risk, vehicle driving and handling performance. LTR (lateral load transfer ratio), which is the rollover index, is significantly relevant to the vehicle lateral acceleration. For reducing the rollover risk, the vehicle lateral acceleration must be decreased. Lateral acceleration depends on the vehicle speed and turning radius. These factors can be controlled by the in-wheel motor torque control. To develop the in-wheel motor torque control strategy, the LTR was calculated from the vehicle dynamics to estimate the rollover. Threshold of LTR was introduced using the vehicle specifiations. LTR error which is the difference between the threshold of LTR and actual LTR was used to control the front and rear motor torques. Motor control strategy was composed of two parts: First, to reduce the vehicle velocity, output torque of the in-wheel motors at all wheels were reduced depending on the amount of the LTR error. In addition, co-operative braking control was performed using the electro-hydraulic braking system. Second, to improve the handling performance, additional output torque control of the front in-wheel motors were carried out. Through the simulation results, it was found that the rollover risk was decreased as much as 30% by the in-wheel motor torque control compared to that of no control

Pedestrian Headforms

Used for pedestrian safety testing, Diversified Technical Systems’ (Seal Beach, CA) pedestrian headforms (which emulate a human head) embedded data acquisition solution are instrumented with a triaxial accelerometer and miniature SLICE NANO data recorder inside and then launched at a vehicle’s hood and windshield to test for potential injuries that may be sustained by pedestrians. DTS’ three-channel SLICE NANO miniature data recorder with 16 GB flash memory offers a cable-free solution for both the 4.5 kg (9.9 lb) “adult” and the 3.5 kg (7.7 lb) “child” headform. The mounting block also houses a DTS ACC3 PRO triaxial accelerometer, which has a mass of 2000 g (70 oz), that measures the linear acceleration and impact forces. Options are also available for other sensor models. “The DAS and sensors are all inside so there are no cables to get tangled up when it’s launched at the car. That also helps with repeatability—something that’s especially important for regulation testing,” said Scott Pruitt, DTS president and co-founder.

Features pedestrian facility include:

  • Equipment and software developed in-house for targeting and aligning the headform which ensures every impact is exactly where it is supposed to be, well within the permitted tolerance.
  • An accurate independent measurement of the headform velocity before impact, for every test, using a laser-based system.
  • Lower-leg tests conducted using a long acceleration distance to ensure the foam at the rear of the leg is not compressed before the impact on the vehicle

A complete suite of impactors, gives capability to perform any type of testing:

  • Headforms Adult (4.8kg) Small Adult (3.5kg) and Child (2.5kg)
  • Euro NCAP / Japan / GTR 4.5kg Adult headform
  • Upper Leg WG17 / EC / Euro NCAP
  • Lower Leg WG17 / EC / Euro NCAP

The WG17 Headform impactors from Humanetics were developed with the Netherlands Organisation for Applied Scientific Research (TNO) in Delft and partners in the Working Group 17 from the European Enhanced Vehicle-safety Committee (EEVC). These headform impactors have been incorporated in a EEVC proposal for a Directive for Pedestrian Safety Tests of passenger cars for the European Commission. The design of the headform is based on the current WG10 headforms, which are currently used as the tool in pedestrian safety evaluations in the European New Car Assessment Program (EuroNCAP).

In June 1997, the European Enhanced Vehicle-safety Committee (EEVC) decided to set up a Pedestrian Safety working group: WG17. The main task of EEVC Working Group 17 was to review EEVC Working Group 10 pedestrian protection test methods from 1994 and to propose possible revisions, taking into account new data in the field of accident statistics, biomechanics and test results. The EEVC WG17 report has been finalized in December 1998. Several improvements in test conditions, requirements and tools (i.e. impactors) have been included. The new EEVC pedestrian protection test methods will be used by the European Commission for further development of regulations in this field.

Since 1994, the subsystem impactors described in the EEVC test methods have been further evaluated and improved. EEVC WG17 has included new impactor specifications in the EEVC test methods:

  • Improvement of the leg-form impactor with a damper in order to avoid vibrations.
  • Alteration of headform impactor material to improve production and durability.
  • Improvement of the dynamic certification procedure of the leg-form and headform impactors in order to better reflect actual use in bumper and bonnet tests.
  • Enhanced durability and repeatability of the headform impactors.
To improve durability and repeatability EEVC WG17 decided to change to a more Hybrid-like head- form, i.e. an aluminium sphere covered with a PVC skin. The headform specifications have been updated in this respect. The outer diameter and mass of the headforms are unchanged. The Humanetics WG17 Headform impactors meet the original certification requirement, which was developed on the basis of a drop test. Meeting this biofidelity requirement meant that the EEVC WG17 subsequently approved the Humanetics WG17 Headform impactor design.
The original headform certification speed obtained from a drop test was only 20-25% of the impact speed on the car bonnet. EEVC WG17 has now developed a new dynamic certification procedure, which better reflects the actual use of headform impactors in bonnet tests.
In 2009 Euro NCAP has introduced a new overall vehicle rating that will put growing emphasis on pedestrian protection in the years to come.  This new rating system was implemented in February 2010.  At the same time, a new European Commission regulation on the pedestrian protection, (EC) No. 78/2009, has been published, which repeals and replaces the previous EC directives 2003/102/EEC and 2005/66/EC.

Vehicle Connectivity

Automotive suppliers and companies from other fields are jockeying to team up with the right group of partners to provide services for connected vehicles and smart cities. The collaborations cross boundaries to include insurance companies, app providers and public services as well as a range technology suppliers. Connected vehicles are rapidly moving into the mainstream, putting pressure on companies to figure out what services and features they want to offer. App companies, cellular and satellite providers, insurance companies, data centers and service providers are all struggling to cash in on the connected car boom. Communication companies like Ericsson are attempting to help vehicle owners find the apps and services they need. Ericsson created a center for app and service providers.

Automakers also detailed the need for multiple partnerships, which are often called an “ecosystem,” during the 2017 TU-Automotive Detroit conference. These ecosystems build upon alliances that have been established in recent years. Consumers who spend much of their time connected to the Web are pressing automakers to provide far-ranging amenities. Today’s technology lets service providers offer a broad range of offerings, making it difficult to determine what users might want and how they can earn revenue. For example, insurance companies that use connectivity to track mileage must decide what else they want to do.

The challenge facing automotive suppliers extends to the public sector. More urban planners are exploring ways to use connectivity to reduce congestion by using vehicle data to adjust stoplights and help drivers quickly find parking, among many other tasks. However, creating the digital infrastructure needed to support various services won’t be cheap, so private companies may be asked to help pay for equipment. This infrastructure will probably include V2V and V2I (vehicle-to-vehicle and vehicle-to-infrastructure) communications. That is expected to reduce accidents, which cost communities and drivers millions of dollars and copious time. When vehicles communicate in this fashion, security is paramount. Green Hills Softwareis addressing this security by partnering with Autotalks and Commsignia to address the huge volume of certificates that will be needed to limit communication to authorized transponders.

Many conference speakers noted that innovative offerings will often come from startups, which can pose challenges for large companies that aren’t used to finding and working with tiny companies. OEMs and Tier 1s will have to devise strategies that let them work with many different partners without spending getting bogged down. While cellular communications will play a central role in connected services, these links may not be the most effective technology for OEMs to transmit over the air (OTA) updates, monitor vehicles’ diagnostic and other tasks. Satellite provider Inmarsat has partnered with Continental to offer OEMs a global network. Handling all this data brings management services and big data analysis into the fray. Rush-hour traffic may tax the data handling capabilities of infrastructure equipment that’s sending infotainment files to vehicles while collecting traffic and safety information. The amount of data created by vehicles will soar even higher when autonomy becomes real. That will impact processing requirements on vehicles and off.