Advances in chassis design improve safety, ride comfort
The chassis manufacturing sector is defined by the shortened development times, increasing use of computer-aided engineering and development tools, integration of new electronic chassis control systems, and the increasing pressure to simplify and standardise the chassis and suspension systems. Development times are reduced with every successive vehicle model, despite the ever-increasing complexity of chassis technology. Development times can be reduced by continuing to cut down the number of physical prototypes and experiments. The development of modern chassis and suspension is possible only with the help of computer-aided engineering (CAE) tools. Over the years, the use of CAE tools showed a drastic improvement in the quality of chassis and suspension systems. These advances have led to considerable improvements in vehicle safety and ride comfort.
The latest software packages are capable of integrating the expert knowledge base of a corporation into a superordinate development environment. It is unlikely that any completely new suspension systems will be developed in the coming years. Instead, legal regulations (low emission limits and low weight chassis), package restrictions, and the integration of new chassis systems such as air springs, roll stabilisers, active body control and electric vehicles force chassis and suspension engineers to develop new systems and solutions.
Big OEMs will continue to use standardised chassis and suspension systems to reduce engineering costs and development time. With regard to chassis and suspension technology, the main challenges being faced by the OEMs are the accurate and reliable prediction, determination of requirements and specifications for new vehicle generations and subsequent development of cost-effective and weight-optimised chassis and suspension solutions which fulfill these requirements.
Chassis manufacturing in India
Companies like KLT Automotive and Tubular Products, ALF Engineering, DuPont, GS Auto, and Metalman Auto are the key manufacturers of different types of chassis systems in India.
Among these, KLT manufactures automotive products, precision tubes, chassis frames, chassis components and body components and assemblies. The company specialises in hydroformed chassis. Hydroforming is a process to expand metal tubes through high water pressure from inside in a closed forming die. Hollow parts can be formed with a complex outer shape and special characteristics through hydroforming process. The hydroforming process can be employed for sheet forming components as well as tube forming components.
KLT set up manufacturing facilities for hydroforming components and aggregates for automotive application in 2006. The facilities include 5000tonne capacity hydroforming press with pressure intensifier and other relevant auxiliary systems, procured from Schuler
Hydroforming, Germany, the pioneer in Hydroforming technology and Hydroforming press and tooling. KLT has also acquired CNC tube bending machine from Chiyoda, Japan, for the bending of tube prior to hydroforming operations.
KLT intends to augment the manufacturing facilities by adding more hydroforming presses (for pre-forming as well as final forming) to meet the increasing demand from domestic and global markets. The company has incorporated robotic loading and unloading facilities on hydroforming press to improve productivity and safety aspects.
The tubes required for hydroforming applications have also been developed by KLT and manufactured in its parent tube plant which has rolling, annealing and testing facilities. Hydroforming is a relatively new process. It is a boon to the automobile industry as now automobiles can be made much lighter by using hydroformed components made up of steel. Structural strength and stiffness can be improved. The tooling cost is reduced as several components can be consolidated into 1 hydroformed part.
DuPont Automotive offers the materials, design technology, predictive engineering and processing capabilities required for innovative automotive chassis design. The company has identified lightweighting opportunities in automotive chassis, suspension and steering systems. Its highly engineered materials retain their strength and stiffness despite heat and chemical exposure and shed pounds in exhaust systems and other automotive chassis components. To help automakers gain 1% to 4% improvement in fuel efficiency, DuPont materials help improve rolling resistance in tyres by 10%. The company is enhancing its benchmark materials to address stricter requirements and improve performance while reducing weight and cost.
ALF Engineering has 11 plants across India and manufactures wide range of chassis and supplies to M&M, Ashok Leyland, Tata Motors, Daimler India Commercial Vehicles and Piaggio. The company manufactures chassis frame, suspension assemblies and hydroformed components for SUV’s, MUV’, LCV’s. It is working on new opportunities in the heavier segment. ALF has indigenously designed and developed hydroformed components for the automotive majors. It has invested in 7 hydroforming presses (1000 - 5000 tonne) and has a centralised hydroforming facility at Nasik. It has also invested in Autophoretic paint shops for chassis at Nasik, Chakan and Hosur offering the latest in cost- effective painting technology.
ALF, the chassis manufacturer for M&M, Ashok Leyland and Tata Motors, has bagged order from Isuzu Motors and has developed chassis for its Pickup and SUV range.
At present the new paradigm is the ‘skateboard’ approach, in which the motor, battery, suspension, brakes, and other components necessary to make the car go, stop, and steer are combined into one unified structure. Then manufacturers can take that structure and mount on it any style of body and interior. It could be a sports car or a crossover. The batteries are contained in folded aluminium boxes which also handle the vehicle load. This is the key to a simple, light and very easy to construct car. It provides a high level of strength and stiffness from a very simple and light structure. The chassis is one of the few items that has to be fabricated. As a majority of items are sourced and attached to the chassis.
Suspension components are made from carbon fiber reinforced components that are 40% lighter than conventional aluminum pieces and made with a proprietary zero waste process. The additional weight of the batteries will cause compression of the springs which in most vehicles will change the suspension geometry. This will also reduce the space available for suspension travel. Such compression might be rarely encountered in an ICE vehicle as
it corresponds to the maximum load.
In an electric vehicle this load will be present at all times, so the suspension travel and geometry should be restored by various modifications. When the spring rate is increased, then the damping rate applied by the shock absorbers should also be increased. If the suspension modifications are by use of coilover or air adjustable shocks then the appropriate damping may be obtained by proper equipment selection.
Some high-end shock absorbers allow the damping rate to be adjusted statically. The simulation of the original vehicle with Macpherson front suspension and leaf spring rear suspension was built using motion view. It was assembled with an engine as the power system and simulated first using a step steer analysis.
Another simulation model of electric vehicle was built by replacing engine system with motor or battery system. Electric vehicles typically mount the battery pack - the car’s heaviest component - as low as possible in the chassis so all that weight has the least effect on handling and driving dynamics. Electric motors and the controllers are smaller than internal combustion engines and can be mounted anywhere there is space. As a result, new electric cars are reverting to a form of ‘body on frame’ construction that was typical in the industry prior to the arrival of uni-body construction. Most trucks still use this approach. The development sources will be shifted from mechanically-oriented chassis and suspension systems to chassis and suspension systems that are focused on mechatronics.
The automobile industry is seeing extensive use of advanced technologies to reduce emission levels, increase fuel efficiency, and improve the driving dynamics of the vehicle. Aluminum alloys are used for automobiles that weigh half that of regular steel vehicles and absorb twice the impact of energy during accidents. Factors such as the rising vendor consolidation, faster replacement market growth, increasing localisation, exportoriented growth, and growing electronic content per vehicle have induced the Indian auto component segment to continue to grow much faster than the OEM segment. According to the Society of Indian Automotive Manufacturers (SIAM), Indian automotive sector today is a $74 billion industry and by 2026, the industry is expected to achieve a turnover of $300 billion- clocking a CAGR of 15%.
The global automotive chassis market is expected to grow at a significant rate owing to the increased sales of automobiles across the world during the forecast period. With the growing economy of emerging markets such as China, India, and Mexico, these countries are also expected to lead in vehicle production and sales. The demand for passenger cars is rising, particularly in emerging economies like Brazil, China, and India, due to a rise in the purchasing power of consumers and the significant economic growth in these countries. China’s massive fiscal stimulus packages in recent years made it the leader in emerging markets. Over the past few years, China has maintained its position as the world’s largest automotive market.
In Europe and North America, the use of automotive lightweight materials has increased and has high penetration rates. The adoption rate of aluminum material is expected to be higher in the automobile industries in China, Germany, Japan, and the US.
The auto component market in India will grow steadily at a moderate CAGR of around 19% by 2020. Production capacity expansion outpacing domestic consumption will drive exportoriented growth in the coming years and will be one of the major factors that will have a positive impact on the growth of the automobile component market in the future. Cost-efficient operations and acceptable quality have increased export volumes for the auto components to global OEMs. Moreover, recent regulations that facilitate 100% foreign direct investment in the automobile industry will attract more joint ventures and whollyowned subsidiaries. This will augment export growth to OEMs in global markets.