SAFE, EFFICIENT VEHICLE SOLUTIONS

Transcription

1 SAFE, EFFICIENT VEHICLE SOLUTIONS Jianfeng Yao, Sam Fredriksson Semcon, Gothenburg, Sweden 1 Abstract Semcon is a partner 1 in the SEVS research project. The SEVS project presents possible transport scenarios for 2030 comprising three vehicle types: City Mover, Long Distance Vehicle and Distribution Vehicle. The City Mover is a small personal transport vehicle using the urban and/or city network as its primary network. Semcon has designed three electrical powered concept vehicles for the City Mover for three scenarios, namely the Eco Political, Eco Individual and the Radicalism in Harmony. These concept vehicles are of course not the only vehicles running in the city 2030 since the traffic will be multifaceted as today but should be seen as examples and carriers of information in the SEVS project. All City Mover concepts are safer than normal passenger cars of today. All three concepts use a premium active safety system. For the Radicalism in Harmony scenario, safety actually has been improved to a degree that no or very limited passive safety is needed since the vehicles never crash when driving in certain zones in the city. These zones are necessary in order to create a traffic milieu for vehicles with a certain level of intelligent communication and safety systems such as Vision Enhancement, Driving Assistant, Dynamic Control, Collision Avoidance and Impaired Driving systems. In the Eco Individual scenario, advanced premium passive safety systems are equipped including, but not limited to Intelligent Airbags, Pedestrian Protection System, Expandable/inflatable beams, New Front Design etc. In the Eco Political scenario, both active safety system and passive safety system are iterated from today s systems with increased protection performance. It is estimated that 80% reduction in fatalities and severe injuries is technically possible even with lighter vehicles. Sophisticated safety systems in vehicles and a well developed infrastructure make it possible. Keywords: Concept car, City Mover, Electrical car, Intelligent Driving System, Active Safety, Passive Safety 1 Partners: SAFER ( Swedish Hybrid Vehicle Centre (SHC) ( Volvo Cars, AB Volvo, Saab Automotive AB, Scania, Autoliv, Chalmers, Viktoria Institute, VTI, SP, Swerea SICOMP, Etteplan, Semcon, Epsilon, Swedish Enery Agency, VINNOVA 1

2 2 Introduction Semcon is a partner 1 in the SEVS research project. The purpose of the project was to explore how safe, efficient and affordable future vehicles should be designed and ascertain what research needs to be performed, with special focus on safety and energy consumption. The project team consisted of members with different areas of expertise in order to explore important synergy effects and possible conflicts between new technologies. The project was initiated by SAFER and Swedish Hybrid Vehicle Centre (SHC) [1]. Research in the automotive industry is generally conducted with the vehicle as the highest level of research. SEVS, however, adopted a more holistic approach in which the vehicle is regarded as a component in a traffic system. While technological uncertainties make it impossible to determine today what will be the right automotive engineering solution in 2030, uncertain social factors play an even bigger part. For this reason SEVS set out to define possible scenarios for the future, based on trends and tendencies in the world of today, namely Incremental, Eco Political, Eco Individual and the Radicalism in Harmony. The scenarios were defined by taking into consideration both a societal perspective and a technological perspective (Figure 1). Figure 1: SEVS principle model of future traffic scenarios 2

3 SEVS analyzed the driving forces behind development in order to determine the feasibility of different types of vehicles. The first phase of the SEVS project resulted in three types of vehicle concepts, City Mover, Long Distance Vehicle and Distribution Vehicle and ideas for future research. 3 Concept Cars by SEMCON City Mover is a small personal transport vehicle which has the urban and/or city network as its primary network. Semcon designed three electrical powered concept cars for the City Mover for three scenarios, the Eco Political, Eco Individual and the Radicalism in Harmony. The work has been done by a team of experienced engineers working with their experience as the main tool in order to evaluate possible designs. It is however important to realize that there will of course be more than one type of car in each scenario in The car fleet will of course in year 2030 still be multifaceted with a number of different vehicles with different price, performance, drive line concept, safety concept, and etc. One of the corner pillars of SEVS has been not to present the most likely scenario and or concept but rather to study the wide spectrum/possibilities of the future. In the same spirit Semcon chose to present concepts addressing different categories of drivers and therefore also with different prices. The price has been normalized by using a blue collar wage as a reference. This should not be seen too quantitative but should rather be seen as that the concept in the Eco Politcal scenario has a price of approximately ½ of a blue collar wage while the concepts in Radicalism in Harmony and Eco Individual has two and three times that price respectively. In order to further emphasis this Semcon chose to name the concepts rather than only discuss the concept car in each scenario. The names of the concept cars are GTE, LeanE and Shuttle Mate for the scenario Eco Political, Eco Individual and Radicalism in Harmony respectively. A brief description of these three scenarios and the concepts is presented below. 3

4 3.1 GTE (Eco Political) Scenario description The public has not changed their lifestyles and values significantly in 20 years. The vision of the car is roughly the same as it has been since the fifties. The price is largely proportional to the size of the car. In addition, the cars most likely are filled with traditional technical inventions such as stereo system, GPS, electric windows but manual climate controls etc. Since small vehicles are considered less worthy and less secure people chooses a bit on the high side when choosing a car. The car shall rather have room for a couple of extra people, or a few extra bags, than be crowded and uncomfortable. Even a small car for commuting to and from work in the city, therefore, holds up to four people. The driver is still speaking of driving pleasure. Politicians have for a long time tried to limit both the amount of vehicles in urban areas and its environmental impact. Vehicles powered by fossil fuels are totally banned in cities and only those vehicles with guaranteed parking are admitted. On major roads, higher priority is given to "fossil-free" vehicles in that they are assigned their own files to increase both safety and traffic flow. Infrastructure investments also include new active safety systems in the form of wireless networks and signaling. By introducing more stringent speed limits the politicians strive to reduce the number of traffic accidents. The traffic is in this way controlled at a steady but very low speed which also makes public transportation a more attractive option. The public transportation service has been greatly expanded and is soon for free. Since people's reluctance to travel together in groups, from one location to another at predetermined times, the politicians are forced to take stronger action to change public behavior and achieve set targets Concept Design and Architecture The GTE is most similar to the cars we are used to today. In this concept, the space between the occupants is reduced since we do not need a tunnel console in the center of the coupe. It can accommodate for maximum two adults and two children (Figure 222). 4

5 Figure 2: GTE concept car The architecture of the GTE is shown in Figure 333. GTE have a traditional wheel suspension, with shaft mounted motors, thereby decreasing unsprung weight and using existing technical solutions. It is a four wheel vehicle and has therefore four motors. Due to weight and performance it will need 235 Nm per motor giving a total torque of 940 Nm to provide an acceleration equivalent to km/h in 10 s. The motors shall have a total power of 20 kw nominal and 60 kw peak to allow acceleration in the entire speed range 0-90 km/h. GTE goes for the battery scenario price-reduction with energy content on pack level of 150Wh/kg. The needed energy content for the GTE is 9 kwh and the battery will have a weight of 60kg and a volume of 30 liters. The maximum C-rate (the charge and discharge rate) at peak power will be 7C and at cruising it will be lower than 1C. Figure 3: Architecture of GTE 5

6 3.2 LeanE (Eco Individual) Scenario description Being eco-correct is cool, good and seen as a sign of culture and class. A vehicle powered by fossil fuels is actually difficult to find because demand is so small. All the same there is a demand of many different types of vehicles, in various sizes and sometimes with very advanced technology. Really exclusive vehicle is completely environmentally neutral to drive and very customized. Commuting vehicles, for example, made for a maximum two persons. Comfort and retro material is not of the same weight as before. Instead, agility is a high priority in tight urban areas and the possibility of parking in a small space. Average speed of these vehicles is quite similar to today's vehicles since the infrastructure, etc. is unchanged. Vehicle development has meant that the vehicles are actively avoiding accidents in a very large extent. However, since the infrastructure has not kept pace, there are still some accidents between different vehicle types. To own your vehicles by yourself is still very important. However, the vehicles have become more flexible in their design, which means that from time to time they can update their vehicle to a different body type, driveline or other special features. There are a whole variety of business models around the vehicle ownership and upgradeability Concept Design and Architecture The LeanE, which is a leaning vehicle, can house two occupants in tandem as shown in Figure 444. During low speed and while standing still, at traffic lights etc, it has two smaller supporting wheels. A recommendation from ergonomics is that there should be as much transparent materials as possible over the beltline to avoid claustrophobic feelings. 6

7 Figure 4: LeanE concept car Figure 555 shows the architecture of the LeanE. The hub motor solution will free space in the coupe that can be used for comfort or reduced size. Due to weight and performance it will need 365 Nm per motor to give a total torque of 730 Nm to provide an acceleration equivalent to km/h in 8 s. The motors shall have a power of 20 kw nominal and 60 kw peak to allow good acceleration in the speed range km/h (top speed 110km/h). The LeanE vehicle uses the most extreme battery option. This battery will have energy density of about ten times better than today which means 700 Wh/kg. The needed energy content for the LeanE is 5 kwh and the battery will have a weight of 7 kg and a volume of 4 liters. The maximum C-rate at peak power will be 11C and at cruising it will be lower than 1C. Figure 5: Architecture of LeanE 7

8 Safe, Efficient, Vehicle Solutions 3.3 Shuttle Mate (Radicalism in Harmony) Scenario description Sometimes, progress really moves fast forward. In this case, both the politicians and market forces pushed the development of vehicles and its infrastructure so that all the previously set targets are met. Moreover, the number of injured and killed on the roads is no longer a topic of conversation because vehicles simply can not collide - with each other or anything else! Vehicles have been redesigned from the ground which resulted in significantly lighter vehicles. They are very easy to steer and stop and traveling on own roads. It is quite natural to go into environmentally neutral vehicle. Driving vehicles that run on fossil fuels is considered not only stupid - it is forbidden! It has even gone so far that more and more people traveling together and you feel no longer a need to own your own vehicle. For longer journeys we travel together with the support of new infrastructure for public transport solutions. There are many different types of vehicle ownership/sharing and the old car pool groups have become very sophisticated high-end solutions including run-up and recovery of the vehicle Concept Design and Architecture The triangular shape of the Shuttle Mate was proven to be a real challenge when it came to the architecture (Figure 666). The greatest challenge was to place the occupants in a way that on one hand was safe in a rollover perspective and on the other hand was likely to be comfortable and ergonomically correct. The Shuttle Mate takes three occupants, two adults and one child. Figure 6: Shuttle Mate concept car The architecture of the Shuttle Mate is shown in Figure 777. The hub motor solution in this 8

9 vehicle will give the chassis and coupe new possibilities since the drive shafts are gone. Due to weight and performance it will need 145 Nm per motor to give a total torque of 430 Nm to provide an acceleration equivalent to km/h in 12 s. The motors shall have a power of 15 kw nominal and 40 kw peak to allow acceleration in the entire speed range 0-60 km/h top speed 70 km/h. For the Shuttle Mate vehicle the Charging while driving scenario is chosen since it is foreseen that the infrastructure will have evolved. There are many charge strips on the roads throughout and outside the city on which the battery can be recharged by inductive charging systems. This battery will have an energy content of 6 kwh, an energy density of 200Wh/kg resulting in a weight of 30 kg. The volume is estimated to 15 liters. The range 60km in the MVEG cycle is when no charge strips are used. In a reality in this scenario the vehicle will more or less have infinite range since there are many charge strips available for charging while driving and the parking lots will also be equipped with charging stations. The maximum C-rate at peak power will be lower in this low weight vehicle with moderate acceleration properties 4C. During cruising it will be lower than 1C as the other vehicles. Figure 7: Architecture of Shuttle Mate 4 Safety solutions It is anticipated that in 2030, the safety performance of a vehicle will be greatly dependent on three systems: Intelligent Driving System (IDS), active safety system and passive safety system as shown in Figure 888. The ADASE safety model is further developed with the 9

10 added Intelligent Driving block [2]. The main focus of the Intelligent Driving is during the normal driving state, even before the active safety systems are triggered. Cooperative systems, combining data from all road users as well as from the infrastructure, is the key factor to realize most of the functionality. Since all vehicles, and many of the surrounding traffic components (signs, red-lights etc), are connected with a wireless and/or telecommunication connection with a large bandwidth, the amount of available data will be enormous. The bottleneck for how safe and efficient the traffic will be depends on how intelligent the use of this data will be. The active safety system can avoid or reduce the severity of an accident by detecting dangerous driving situations, giving warning messages, automatic braking or even automatic steering. The passive safety system is the last defense to protect occupants or vulnerable road users, VRUs, in case an accident is unavoidable. The passive safety systems also include the pre-activated safety systems such as seatbelt pretensioner, pop-up bonnet for pedestrian protection and pop-up crash box. Figure 8: Modified ADASE safety model SEVS 2030 Different safety strategies are adapted for three vehicle models with a varied focus on the IDS solutions, active safety solutions and passive safety solutions as shown in Table

11 Table 1: Safety strategies for three city mover concepts It is foreseeable that in 2030, due to the fast development of sensor technology, control technology and software technology, active safety systems will play a major role in vehicle safety. All the vehicles will have highly developed premium sensor & control systems compared to today s (2010) cars. These sensor and control systems can be used to increase the vehicle safety performance. The sensors used for active safety systems will be a combination of radar, camera, LIDAR, Stereo-camera etc. All the data from these sensors will be used to realize a number of functions to mitigate or even avoid accidents. The cost of most active safety systems will be affordable and thus all three car models will be equipped with a similar premium active safety system. Figure 999 lists the current active safety technologies which are categorized according to their functions. A premium active safety system in 2030 will have the following functions: vision enhancement, driving assist, vehicle dynamic control, collision avoidance, impaired driving. It is believed that these systems will be carried over to 2030 and new technologies will be further developed. 11

12 Figure 9: Active safety systems in 2030, a sketch The Intelligent Driving Systems will also be developed, however, in a slower pace due to the involvement of expensive infrastructure modifications. In combination with active safety system, it may lead to (for one of the scenarios) a vehicle that is capable of driving itself autonomously under certain conditions and never crash. It is then possible to order the vehicle to your home or let it drive you home safe after a dinner downtown. Is it even necessary with a driving license? The passive safety solutions are the last defense to protect occupant and VRUs. Its importance can never be neglected only if there is a risk of crash accident. The requirement of low energy consumption in 2030 leads to smaller and lighter City Movers compared with the current vehicle fleet. However, the normal sized vehicles will continue running on roads and thus there is a risk of collision. Due to the large difference in the size and weight, the City Movers are more vulnerable when impact with the normal sized cars. This imposes a higher requirement for the safety performance of City Movers GTE (Eco Political) The GTE will have an active safety system that is iterated from today s systems, including functions such as autonomous braking and steering. Functions such as platooning to make the traffic more dense and efficient will be available. The society will have set up a lot of regulations for where cars are allowed to drive, automatic 12

13 control of the driving speed etc. Other functions will be forced guiding of driving routes to avoid congestions. The GTE will have a passive safety that is iterated from today s systems with an affordable cost (Figure ). The BIW (body-in-white) of the GTE is similar to today s monocoque chassis with a crumple zone in front to absorb crash energy. In 2030 the traditional steel monocoque will most likely be replaced by the Ultra Light Steel Auto Body (ULSAB) with hydro-formed parts, sandwich steel and laser beam welding. ULSAB will also be mixed with aluminum, magnesium and other lightweight materials. Closures will be in aluminum and high strength steel beams. Interior furnishing will be made in lightweight materials. The occupant restraint systems are similar to those used today. Three point seatbelts with pretensioners are used to tight the seatbelt in the pre-crash phase. The occupant airbags for the protection in front crash and side air-curtains for the protection of side impact are installed. The passive safety systems used today in the premium vehicle models will be a standard feature in 2030 due to reduced cost. These systems are listed but not limited to as the following: Intelligent airbag system. The airbag system can detect the weight, height, posture of the occupant. The deployment of the airbag is optimized to give a maximum protection and avoid any misuse. Foams are used to reinforce the BIW in critical locations to increase the stiffness. It can also fill up the crash members to give a maximum energy absorption performance. Pedestrian protection system such as pop up hood and external airbags can prevent any serious injuries in pedestrian accidents. Body structure is adapted for the small offset crash, better usage of the door structure as load path between A- and B-pillars. Expandable/inflatable beams for increased rigidity in side impact without increased size of the car. It will also help to increase the rigidity of the occupant cabin in frontal crash. 13

14 Figure 10: Medium passive safety systems for GTE LeanE (Eco Individual) For the LeanE, the road infrastructures in 2030 will be similar to those of today. The vehicle safety is totally dependent on its own safety performance. The LeanE will have both a premium active safety system and a premium passive safety system. The premium own safety solutions can totally avoid serious injuries and fatalities. The LeanE has a premium passive safety system that can substantially decrease the risk of fatalities and severe injuries in crash accidents. An illustration of the passive safety solutions used in the LeanE model is shown in Figure 11. Figure 11: Premium passive safety systems for LeanE 14

15 Structurewise, the LeanE provide a super stiff occupant cabin and a desirable deformation space. The car body of the LeanE is made of CFRP (carbon fiber reinforced panel) which makes the occupant cabin extremely stiff while at the same time reduces the total weight of the vehicle. The front end is designed in a shape that can avoid a direct hit in a front crash and also avoid a direct hit to a pedestrian. Due to the short length of the vehicle front, expandable front crash members and/or external airbag(s) are installed which can provide extra deformation space to absorb crash energy. The front wheel as well as the rear wheel can be crushed and guided under the vehicle to provide extra deformation space. A rigid roof structure is designed to withstand a hit from other vehicles when LeanE is lying on the ground during a rollover accident. The side doors are equipped with reinforcement beams along the load path of the frontal crush member. These reinforcement beams can also prevent large intrusion of the door panel during a side impact. To further improve the crashworthiness in side impact, external side airbags can be used to provide extra deformation space. The LeanE uses a superb occupant restraint system. Two-stage airbag systems are installed both for the driver and the passenger. A reversible, small volume, low-pressure airbag will be first triggered in the pre-crash phase if the frontal crash is judged to be happen. In the crash phase, the second airbag will be further deployed. There are also reversible airbags installed for the protection of knees and feet which can be activated during the pre-crash phase. The 4- point seat belt systems are used which can prevent the ejection of occupant during rollover accidents. The side air curtains and roof air curtains can protect occupants in all direction impacts Shuttle Mate (Radicalism in Harmony) The Shuttle Mate reaches the highest levels in terms of safety supported both by a state of the art sensor system as well as IDS and cooperative systems. Therefore the vehicle is fully integrated with the infrastructure. If this concept is stretched to the limit of what s possible, the Shuttle Mate will be a vehicle that never crash! To realize this vision the following condition must be fulfilled: Only intelligent vehicles are allowed within the IntelliZone. Old vehicles which don t support the infrastructures demand regarding communication, and which doesn t have enough of intelligent safety systems onboard are simply not let into this zone. Once the society has decided this, it will be a significant driving force for people to use the 15

16 intelligent vehicles instead of the ordinary ones, making it possible for the society to further invest in, and expand, this zone. The Shuttle Mate will be driven by a driver, but at all times supervised by the technology, which will help and even override the driver s maneuvers when so is needed to avoid an accident. The traffic flow will be controlled so that all unnecessary queues and congestions will be avoided. In fact, since the speed of the vehicles can be controlled, there will be no need for trafiic lights since the traffic flows will be seamlessly merged into each other in crossings. The Shuttle Mate will be able to drive autonomously within the IntelliZone which opens up for possibilities like Drink & Drive concepts. Take the Shuttle Mate to the pub after work, have a few beers and let the Shuttle Mate drive you home afterwards. The question is if this is a development that we would like to see. As Shuttle Mate will be a vehicle that never crash! Thus no specific passive safety system is required for the Shuttle Mate. 5 Discussion and Conclusions The SEVS project adopts a holistic approach, taking into consideration both a societal perspective and a technological perspective as two driving force. Four future scenarios have been defined to understand how a sustainable transportation system should be developed and implemented. Semcon has designed three different concept vehicles, one concept each for the Eco Political, Eco Individual and the Radicalism in Harmony scenario respectively. The concepts have shown that future vehicles and road transports can be both very safe and energy efficient. It is estimated that 80% reduction in fatalities and severe injuries is technically possible even with lighter vehicles. Sophisticated safety systems in vehicles and a well developed infrastructure make it possible. The only way to significantly reduce fatalities and injuries is by considering technology, human behaviour and infrastructure solutions. Active solutions like communication and control systems and passive solutions like traffic separation will play important roles. 16

17 No Crash is the vision for the Radicalism in Harmony scenario where Intelligent Driving system, IntelliZones and active safety give us a traffic system where no vehicles crash with each other. In the other two scenarios there is still a need for passive safety as a complement to Intelligent Driving Systems and active safety. The active and passive systems described, will substantially reduce the risk of crashes and injuries. Semcon believes in building concepts together with mathematical/virtual models to visualize and understand technology. It is also a good way to form a team and make it strive in the same direction. We can see that the concept could either be a complete vehicle or part of a vehicle, typically the compartment to study safety and energy aspects and ergonomics etc or the battery system to study the electricity system in aspects of safety, efficiency and life time etc. References [1]. SEVS Project (2010). [2]. ADASE Consortium (2004). ADASE project information, Fifth EU Framework Programme, Acknowledgement Semcon like to acknowledge the great work of all members in the cross-functional Semcon team. We also like to thank the SEVS project members for the good collaboration in this project. 17