COPYRIGHT NOTICE AND LEGAL DISCLAIMER

Transcription

1 Contents Introduction... 6 Electrification within the chassis... 7 Chassis performance... 9 Design compromise... 9 Manufacturing economics Platform development and component commonality Noise vibration harshness Key Development drivers Greenhouse gas emissions and fuel efficiency The European Union The United States Japan China Other countries...17 Chassis materials developments Increasing electrification Electronic systems integration The packaging dilemma The future for chassis design Suspension systems Challenges and barriers Suspension technology development passive moving to active Kinematics and elastokinematics Suspension element technology Control arms Spring systems Active body control Anti-roll or stabiliser systems Adaptive damping system Air suspension Pneumatic and hydropneumatic systems The skyhook control strategy Active suspension systems Electronic Damper Control (EDC) Active Suspension Geometry (ASG) Semi-active suspension BWI MagneRide: Magneto-rheological damping Active electronic suspension system Recuperative damping systems Future trends Chassis and corner modules Steering systems IHS Automotive SupplierBusiness COPYRIGHT NOTICE AND LEGAL DISCLAIMER 2013 IHS. No portion of this report may be reproduced, reused, or otherwise distributed in any form without prior written consent, with the exception of any internal client distribution as may be permitted in the license agreement between client and IHS. Content reproduced or redistributed with IHS permission must display IHS legal notices and attributions of authorship. The information contained herein is from sources considered reliable but its accuracy and completeness are not warranted, nor are the opinions and analyses which are based upon it, and to the extent permitted by law, IHS shall not be liable for any errors or omissions or any loss, damage or expense incurred by reliance on information or any statement contained herein. For more information, please contact IHS at customercare@ihs.com, IHS CARE (from North American locations), or +44 (0) (from outside North America). All products, company names or other marks appearing in this publication are the trademarks and property of IHS or their respective owners edition IHS

2 Electrically Power Assisted Steering (EPAS) Surface acoustic wave Software enabled features Electro-Hydraulic Power Steering (EHPS) Electric Power Steering (EPS) Active Front Steering (AFS) Four-wheel steering Steer-by-wire Automated parking Braking system development Anti-Lock Braking System (ABS) Electronic Braking System (EBS) or Electronic Brake Distribution (EBD) Brake Assist (BA) Autonomous emergency braking Ceramic composite brakes Lightweight brake discs Brake-by-wire Electro-hydraulic brake-by-wire Electro-mechanical brake-by-wire Regenerative braking systems and brake blending Vehicle stability systems Four-wheel drive (4WD) Emissions and Fuel Economy Active Torque Dynamics (ATD) Safety and AWD Technologies and Challenges Electric AWD Integration of Control Systems Active All Wheel Drive (AWD) Torque vectoring Future trends Supplier Profiles Autoliv Benteler Bharat Forge Bosch Brabant Alucast BWI Group Casti SpA Continental ixetic JTEKT KYB Magna Magneti Marelli Mando Corporation Mubea NSK Schaeffler Sogefi tedrive Tenneco ThyssenKrupp Tower International edition IHS

3 Trelleborg TRW Automotive VB-Airsuspension WABCO ZF Figures Figure 1: Additional functionality requires higher voltages 48 volts... 8 Figure 2: Conventional suspension compromises... 9 Figure 3: Matching and similar parts for the Volkswagen B/C platform Figure 4: Common and matching parts (Chassis, drivetrain, steering system) for the Volkswagen B/C platform Figure 5: Progress from platform through modular to assembly kit strategy for Volkswagen Golf Figure 6: Volkswagen MQB platform Figure 7: Additional functionality requires higher voltages 48 volts Figure 8: The complex functional harmony required to provide driving quality Figure 9: Global CO 2 (g/km) progress normalised to NEDC test cycle Figure 10: CO 2 (g/km) performance and standards in the EU new cars Figure 11: Additional functionality requires higher voltages 48 volts Figure 12: Weight share of modules and their weight increase Figure 13: Aluminium steering knuckle Figure 14: A lightweight strut with a fibreglass wheel carrier Figure 15: Average profit per vehicle versus CO 2 compliance costs Figure 16: Global market revenue forecast for OEM electronic systems (billions) Figure 17: Electronic Stability Control installation rates Figure 18: High performance domain control ECUs can simplify overall network complexity Figure 19: A schematic of data fusion from multiple sensors Figure 20: X-by-wire roadmap Figure 22: Electrical power requirements for NEDC and actual customer requirements for various vehicle classes Figure 23: The extended performance envelope for fully active suspension compared to conventional passive and semi-active systems Figure 24: Ford Focus control blade suspension Figure 25: Additional functionality requires higher voltages 48 volts Figure 26: Typical control arm designs Figure 27: Suspension control arm configurations Figure 28: BWI s Active Stabiliser Bar System Figure 29: Dynamic Ride Control main module schematic Figure 30: A schematic of Monroe s kinetic system Figure 31: Continental s 4-Corner air suspension system Figure 32: Continental s air suspension system Figure 33: CO 2 reduction using pneumatic suspension systems Figure 34: Graph showing the range in which CDC can continuously vary damping forces in compression and rebound Figure 35: CDC dampers with internal and external valves Figure 36: Cross section of a MagneRide actuator Figure 37: Comparison of force-velocity characteristics of a MagneRide damper, typical variable valve dampers and a passive damper Figure 38: Bose s fully electromechanical front and rear suspension modules Figure 39: A schematic representation of Genshock technology Figure 40: Steering system design compromise (EPAS) edition IHS

4 Figure 41: BWI s corner module Figure 42: MOBIS front chassis module Figure 43: Additional functionality requires higher voltages 48 volts Figure 44: Mechanical and electric control systems for EPAS Figure 45: Differing steering rack types, force and mechanical performance by vehicle class Figure 46: A schematic of AFS used in a driver assistance function to enhance vehicle stability Figure 47: Renault s active four-wheel steer systems as fitted to the Laguna GT Figure 48: Nissan s steer-by-wire system Figure 49: A schematic illustrating 4 Wheel Active Steer functionality Figure 50: Ford s park assist system Figure 51: Brake control systems roadmap Figure 52: Continental s electronic wedge brake on test Figure 53: Continental s electro-hydraulic combi braking system layout Figure 54: By-wire brake system layout with regeneration Figure 55: Mazda s supercapacitor based regenerative braking system layout Figure 56: Continental s regenerative braking system layout Figure 57: Comfortable regeneration requires uncoupling the pedal and quiet and highly dynamic of braking force regulation Figure 58: Bosch s yaw torque compensation system Figure 59: Attributes of lifestyle and AWD wagons and performance AWD vehicles Figure 60: Attributes of SUVs and crossover vehicles Tables Table 1: Comparison between various automotive suspension systems Table 2: Front axle design proportions, worldwide light passenger vehicles (%) Table 3: Front axle design by segment, worldwide light passenger vehicles (%) Table 4: Rear axle design proportions, worldwide light passenger vehicles (%) Table 5: Rear axle design by segment, worldwide light passenger vehicles (%) Table 6: Advantages of EPAS edition IHS

5 Introduction Chassis technology today is one of the key functional areas responsible for overall performance in terms of vehicle dynamics, safety and fuel efficiency, and these functions can be seen as the key contributor to competitive advantage. At its simplest the chassis can been defined as the frame of the vehicle plus its running gear consisting of steering, suspension, wheels and brakes. However, today this description misses an essential point in that the chassis now is a complex set of components that are responsible for the vast majority of the ride, handling, comfort and safety. Furthermore, through the use of advanced materials and systems it has a significant role to play in reducing CO 2 output. The chassis frame itself must deliver a wide range of attributes depending on the required performance of the vehicle, and even entry-level chassis systems have undergone significant changes over the past decade, changes that will become more pronounced as more electronic systems are used. In terms of basic functions the chassis must: Remain structurally sound and safe over the operational life of the vehicle in conditions over and beyond those usually encountered. And, in fact good chassis design in all areas has a significant part to play in promoting longevity within the vehicle design; Carry the load of the engine, transmission, body etc. as well as the passengers and any other payload in safety and comfort, both of which are key competitive issues today; Withstand the forces of sudden acceleration, braking or cornering in such a way as to maintain both comfort and control; and withstand the stresses caused by bad road conditions and isolate the passengers and load from unpleasant effects from the road surface. Therefore, the chassis frame, or its fully integral equivalent, is the foundation for the vehicle s driving dynamics, and has an enormous effect on cost, weight and all aspects of the performance of the vehicle. There is an intimate connection between the chassis design and performance, and the essential DNA of the vehicle. The way that systems are integrated today the marrying of sensor technology, electronic and mechatronic systems with the various basic components of the chassis is therefore a key battleground for OEMs. This also means that the management of the compromises in suspension performance, safety systems, cost and weight are increasingly important aspects of differentiation. A good example of this approach is the Ford Focus where the company strived to give the vehicle a sporty driving experience using more advanced suspension technology. Ford s Control Blade system is an innovative independent rear suspension that uses a one-piece pressed steel component in place of a trailing arm and cast knuckle. Three lateral links control toe, camber and lateral forces. Its extensive use of stamping for key components reduces cost, unsprung weight and assembly time. The idea behind this suspension system is to separate and dedicate system functions to single subsystems or components in order to avoid trade-offs in design. For example, rear wheels are allowed to react independently to rough surfaces, enabling a smoother ride. In addition, the trailing link between the rear wheels and the body is flexible, making it possible for the wheels to recess backwards and absorb impacts from rough surfaces. At the same time, lateral stiffness is enhanced in the multi-link suspension system improving steering precision by helping the vehicle remain agile and stable in response to side forces. Finally, the rear suspension characteristics match those in the McPherson strut front suspension and increase overall vehicle stability and driving dynamics edition IHS

6 Electrification within the chassis Chassis systems and components have changed rapidly over the past few years, as the introduction of electronic systems has enabled levels of comfort and road-holding to improve. These range from the widespread introduction of active and semiactive suspension systems, through to electric power steering and additional vehicle stability and safety systems. Such systems bring with them cost considerations but are at the heart of competitive offerings and now being used throughout the vehicle range as system volume and cost reduction allow. Chassis design remains a delicate balance between cost and sophistication, and although the use of innovative pneumatic suspension, for instance, may be a significant differentiator in the luxury and luxury SUV segments, the improvement of vehicle dynamics in the volume A and B segments is also critical to winning customers. In addition, chassis systems are a market sector that has been notoriously difficult to make money from, particularly in the area of conventional chassis, steering, brakes and suspension. However, the enhancement of vehicle dynamics and added safety systems through electronics and mechatronics can bring better performance characteristics, additional customer benefits and cost benefits. The purpose of a modern chassis and suspension is not just to provide superior safety and simple, straightforward handling, but also optimum comfort with maximum agility. The two main factors crucial to the character of a car s chassis are the steering and the springs/ dampers, and in the past, with conventional design, depending on the chassis set-up, the OEM might choose to place greater emphasis either on comfort or sporting performance. Active and semi-active components, and the addition of electronic systems means that it is now possible to sidestep the traditional compromise in suspension and chassis design and deliver performance that brings the best of both worlds. In particular MR fluid dampers offer the potential for low cost and high performance semi-active control as availability is widened. However, many systems are currently expensive and are likely to remain limited to vehicle sectors where margins can justify the cost premiums. Once again although electronic integration and control are bringing their beneficial effects, over the next few years a greater degree of active systems will begin to appear with the potential for rapid cost reduction, the removal of costly air systems for some vehicles and greater levels of application in medium to lower-end vehicle segments. The prospect for the introduction of fully active suspension (spring and damper control) as well as other active systems will be significantly enhanced with the introduction of 48-volt vehicle architecture. The automotive industry moved from a 6V supply to a 12V supply over 30 years ago, a change that required massive investment at the time. Starting in the mid-1990s, the auto industry began considering a change to 42-volts, and created a formal consortium, headquartered at MIT to help implement the standard. However, the effort did not gain sufficient market traction for a number of reasons, including cost and technical feasibility, as well as the development of solutions within the existing 12-volt standard architecture. In June 2011, BMW, Daimler, Volkswagen, Audi and Porsche released a joint statement on their agreement to implement a number of common architectural elements for their on-board power network: an additional 48-volt subnet; a charging connector type for all plug-in vehicles (i.e., Combined Charging System); and CAN bus interfaces supporting partial network operation. The 48-volt on-board power-net would supplement the 12-volt net for high-power applications such as electric power steering (EPS), brake-by-wire and other systems. At the time the group of five OEMs noted that implementing functions and devices requiring high-current loads in a 12- volt supply network is becoming increasingly difficult in terms of both technology and cost. As more high-power devices are being added to vehicles overall, it becomes increasingly difficult to drive these functions out of a 12-volt architecture, both from a technical and economic point of view. This is why BMW and other major car manufacturers decided to add a second system of 48-volts into future car models to supplement the existing architecture edition IHS

7 This will facilitate easy and cost-efficient integration of high-power components in the future and will enable new innovative functions, said Giuseppe Mascolino, BMW, head of E/E architecture, system functions, software development, and e-mobility. The 48-volt and 12-volt subnets are to be connected through a bi-directional DC/DC converter, enabling the easier integration of high-current devices into vehicles at lower cost and with improved quality. Energy recuperation is the key to ground-breaking solutions that the motorist can afford and this has caused the industry to re-visit the previously mooted higher than 12-volts, but less than 60-volts, electrical architecture, comments Nick Pascoe chief executive and chief technology officer at Controlled Power Technologies. Mild electrification deploying a proposed 48 volt standard will be a major factor for enabling the required motor-generator efficiency and power levels. Pascoe says the industry has estimated the additional cost to the motorist to achieve the required 30% reduction in CO 2 emissions at $1,500 for a family sized saloon. This is significantly less than the $7,500 US federal subsidy for electric vehicles; an on-cost that would seem to remain unavoidable unless there is a significant breakthrough to reduce battery cost. Automakers have a broad palette of hybrid technology options, says Pascoe. Some however are more expensive than others. Mild and full hybrid vehicles including plug-in hybrids, for example, operating between 200 and 600 volts, incur significant additional development and product costs to the automaker, which then have to be passed on to the consumer or absorbed by the OEM; hence the need for governments to subsidise electric vehicles. Consequently such hybrid and electric vehicles are unaffordable for most motorists even with government subsidies. Figure 1: Additional functionality requires higher voltages 48 volts Source: BMW The recuperation energy potential of a downsized gasoline engine equipped with a powerful water-cooled starter-motor and generator is significant. At 48-volts a range of options becomes available, such as CPT s SpeedStart, to provide torque assist to the engine for additional acceleration torque, reduced fuelling during cruise conditions, and harvest kinetic energy during braking. Brake energy alone is worth more than 60kJ/km accumulated over the New European Drive Cycle. Not only does 48-volts provide a solution for more efficient powertrains, but also for meeting other increasing vehicle energy demands already severely stretching the capabilities of a 12V/3kW alternator. This includes the wide range of electrically powered auxiliary systems such as cooling fans, water pumps, and electric power assisted steering, all integral to hybridisation, as well as improving passenger safety, security and comfort systems. These higher power electrical 2013 edition IHS