Aslan B.,Arts et Metiers ParisTech |
Semail E.,Arts et Metiers ParisTech |
IEEE Transactions on Energy Conversion | Year: 2014
This paper studies magnet eddy-current losses in permanent-magnet (PM) machines with concentrated winding. First, space harmonics of magnetomotive force (MMF) and their influence on magnet losses in electrical machines are investigated. Second, an analytical model of magnet volume losses is developed by studying the interaction between MMF harmonics wavelengths and magnet pole dimensions. Different cases of this interaction are exhibited according to the ratio between each harmonic wavelength and magnet pole width. Then, various losses submodels are deduced. Using this analytical model, magnet volume losses for many slots/poles combinations of three-, five-, and seven-phase machines with concentrated winding are compared. This comparison leads to classify combinations into different families, depending on their magnet losses level. Finally, in order to verify the theoretical study, finite-element modes are built and simulation results are compared with analytical calculations. © 1986-2012 IEEE. Source
« DLR signs cooperation agreement with Canadian universities to focus on lightweighting and crashworthiness | Main | Siemens and Valeo to form joint venture in high-voltage electric powertrains » A new study by a team from the University of Edinburgh and independent engineering company INNAS BV has found that, when factoring in the additional weight and non-exhaust PM factors, total PM emissions from electric vehicles (EVs) are equal to those of modern internal combustion engine vehicles (ICEVs). Non-exhaust PM factors include tire wear, brake wear, road surface wear and resuspension of road dust. For PM emissions, EVs deliver only a negligible reduction in emissions, the team found. Compared to an average gasoline ICEV, the EV emits 3% less PM ; compared to an average diesel ICEV, the EV emits 1% less PM . Therefore, Victor Timmers and Peter A.J. Achten conclude, the increased popularity of electric vehicles will likely not have a great effect on PM levels. Their paper is published in the journal Atmospheric Environment. Non-exhaust emissions tend to contain mostly PM , but a significant proportion of the emissions contains fine PM as well. The chemical characteristics of non-exhaust PM emissions vary per source, but are mainly made up of heavy metals such as zinc (Zn), copper (Cu), iron (Fe) and lead (Pb), among others. There are several toxicological studies that have found links between non-exhaust emissions and adverse health effects, such as lung-inflammation and DNA damage, and a review of epidemiological studies concluded that PM indeed has an effect on mortality. … It can be hypothesized that each of the sources of non-exhaust PM emissions should be influenced by vehicle weight. We know that road abrasion and tire wear are caused by the friction between the tire thread and road surface. Friction is a function of the friction coefficient between the tyres and the road, as well as a function of the normal force of the road. This force is directly proportional to the weight of the car. This means that increasing vehicle weight would increase the frictional force and therefore the rate of wear on both the tire and road surface. Brake wear is caused by the friction between the brake pads and the wheels. The energy needed to reduce the momentum of a vehicle is proportional to the vehicle’s speed and mass. Therefore, as the mass of the vehicle increases, more frictional energy is needed to slow it down, leading to greater brake wear. Timmers and Achten analyzed the existing literature on non-exhaust emissions of different vehicle categories, and found that there is a positive relationship between weight and non-exhaust PM emission factors. Further, they found that EVs are on average 24% heavier than equivalent ICEVs. For example, the Ford Focus Electric and gasoline-powered Ford Focus hatchback have almost exactly the same specifications; the EV, however is 219 kg heavier. Likewise, the Honda Fit EV is 335 kg heavier than the conventional version; the Kia Soul EV is 311 kg heavier than the regular Kia Soul, etc. A 2013 study by a team at Paul Scherrer Institute found that an increase in weight of 280 kg will result in a PM increase of 1.1 mg per vehicle-kilometer (mg/vkm) for tire wear, 1.1 mg/vkm for brake wear and 1.4 mg/vkm for road wear. For PM , these values are 0.8 mg/vkm, 0.5 mg/vkm and 0.7 mg/vkm for tire, brake and road wear, respectively. However, a different study found that the brake wear of EVs tends to be lower because of their regenerative brakes. Because there is little research which has investigated the actual reduction in emissions resulting from EV braking, Timmers and Achten assumed a conservative estimate of zero brake wear emissions for EVs. Based on a different study, they assumed a linear relationship between weight and resuspension, and used a 24% increase in resuspension for EVs (due to the on average 24% increase in weight). On the combustion side, the advent of PM emission standards and new particulate filter technology has greatly reduced exhaust particle emissions from new ICEVs. Averaging the emission factors from US and European emission inventories, Timmers and Achten obtained a PM emission factor of 3.1 mg/vkm for gasoline cars and 2.4 mg/vkm for diesel cars. In terms of PM , these values were 3.0 mg/vkm and 2.3 mg/vkm for gasoline and diesel cars, respectively. … EVs are not likely to have a large impact on PM emissions from traffic. Non-exhaust sources account for more than 90% of PM and 85% of PM emissions from passenger cars, and this proportion is likely to increase in the future as vehicles become heavier. Policy so far has only focused on reducing PM from exhaust emissions. Therefore, future European legislation should set non-exhaust emission standards for all vehicles and introduce standardized measurement methods. In addition, it is recommended that EV technology such as lightweight car bodies and regenerative brakes be applied to ICEVs, and incentives provided for consumers and car manufacturers to switch to less heavy vehicles.
News Article | February 1, 2016
As infotainment systems in vehicles become more advanced, the concern is drivers dangerously being distracted and taking their eyes off the road for too long. To help eliminate that, Synaptics is collaborating with auto supplier Valeo to create an in-vehicle display called ClearForce tech, which would revolve around force-sensing haptic technology, as reported by Engadget. The system would designate certain feels to specific controls, allowing drivers to keep their eyes on the road, while comfortably selecting whatever it is they want to change, according to its feel. The haptic technology could foreseeably be used to change songs, activate GPS directions or control heating and cooling. Such an interface would definitely pave the way for a safer driving experience if adopted by automakers and infotainment manufacturers in the way that Engadget is reporting, although there hasn't been any word of when they'd hit the market or which car companies or infotainment producers will be using it. Whenever Synaptics' ClearForce technology does impact vehicles, though, it will likely have some competition. At the Consumer Electronics Show (CES) 2016 in Las Vegas last month, Bosch revealed its NeoSense touchscreen system, which also uses haptic technology. A Tech Times reporter, going hands-on with the NeoSense, reported at the time that each button gave off its own unique feel. One was smooth, another coarse and one was equipped with grooves. Like Synaptics' ClearForce system, NeoSense's interface allows drivers to set the trigger force toward the force needed to be applied to each button, ranging from the slightest touch to most forceful.
« Jaguar Land Rover in two UK projects worth ~$16M to advance connected and autonomous vehicle technology | Main | Synaptics partnering with Valeo on automotive touchscreen with haptic feedback » Sensata Technologies, a manufacturer of sensing, electrical protection, control and power management solutions, has developed a line of smaller, lighter Micro-fused Strain Gage (MSG) pressure sensors for use in next-generation brake systems for hybrid, electric, and conventional vehicles. The eXtra-small Form Factor (XFF) sensor is available for design-in beginning January 2016. Sensata’s automotive MSG pressure technology will now be offered at less than 5 grams, with a body diameter less than 7.8mm, and a height less than 30mm, including its revolutionary spring contact system. This provides system manufacturers with a new degree of design flexibility and including industry leading performance. The new XFF platform utilizes a modular port design, catering to a wide-range of system pressures, and a modular circuit architecture offering high-fault-detectability enabling system manufacturers to meet technical safety requirements associated with ISO26262. Sensata’s MSG technology offers analog and digital integrated pressure and temperature signal conditioning delivering an accurate, stable signal over wide operating temperature (-40° to +140° C) and pressure ranges. Beyond hybrid and electric vehicles, this MSG form factor is ideal for integrated brake modules which eliminate the vacuum booster. This development enables improved fuel economy and enhanced emergency braking performance in all vehicle types. —Vineet Nargolwala, Vice President and General Manager, Automotive Performance Sensing in North America, Japan and Korea
« Synaptics partnering with Valeo on automotive touchscreen with haptic feedback | Main | Daimler & enercity storing new replacement EV batteries in working 15 MWh grid storage system; “living storage” » A new report from the University of Michigan Transportation Research Institute (UMTRI) reviews the major advantages and disadvantages associated with battery-electric vehicles (BEVs) and fuel-cell vehicles (FCVs). The team of Brandon Schoettle and Dr. Michael Sivak also incudes information for current gasoline-powered internal combustion engines as a baseline comparison. In addition to reviewing the technical literature, the UMTRI researchers interviewed experts in the automotive and energy sectors regarding their views concerning these issues. Among their findings: BEVs currently offer the most readily available alternative fuel source via the existing electric grid. Additionally, more BEV models are available to the public (relative to fuel-cell vehicles) and they offer the best fuel economy, resulting in the lowest cost to operate (per mile). BEVs also tend to produce the lowest amount of greenhouse gases (well-to-wheels) per mile. However, the driving ranges of these vehicles are currently the lowest of any vehicle type, while also requiring the longest time to refuel or recharge. FCVs have significantly longer driving ranges and lower refueling times than comparable BEVs, and it is also possible for them to use the least amount of petroleum (well-to-wheels) per mile, depending on the type of hydrogen used. On the other hand, only a small number of vehicle models are available, and only in the most recent model years. Similarly, the hydrogen-refueling infrastructure is practically nonexistent outside of California. There is a general consensus among the experts that expansion of the hydrogen infrastructure needs to precede the mass introduction of FCVs in order to raise consumer confidence in the availability of hydrogen fuel. Both alternative fuels and vehicle types require additional training for emergency responders and mechanics, but also generally require lower overall maintenance than a traditional gasoline-powered vehicle. Based on the average mix of renewable and non-renewable electric power sources in the US, the average well-to-wheels GHG emissions for BEVs is the lowest, at 214 g/mi. Depending on whether gaseous or liquid hydrogen is used, the corresponding values for FCVs range from 260 to 364 g/mi, respectively. Gasoline-powered vehicles produce the most GHGs per mile, ranging from 356 to 409 g/mi, depending on the specific type of ICE (direct versus traditional fuel injection, respectively). As a comparison baseline for the refueling infrastructure, the UMTRI team noted that there are approximately 114,000 individual gasoline stations covering all 50 states and the District of Columbia. The cost of installing a gasoline station is typically in the range of $1 million to $2 million. Expansion of the BEV charging network is relatively inexpensive—approximately $1000 for home-based charger installation, and ranging from approximately $10,000 to $100,000 for public stations. Hydrogen refueling stations currently have a relatively high cost for construction and installation, costing approximately $3 million to $5 million for a public station.