Schaeffler, an integrated global supplier to the automotive and industrial sectors, produced an interesting list of ten technologies that will allow combustion engines to continue making progress in efficiency and in reducing CO2 emissions, adapting to new regulations and helping to mitigate climate change.
The concept of combining a combustion engine with an electric one and an energy recovery and storage system has proven to be very valid in reducing consumption and emissions; and it will remain in effect for the next decade. Combustion engines will evolve to harmonize with the hybrid system and to continue optimizing its operation. The benefit of the parallel hybrid concept is the high degree of flexibility of the engine families that can be used, both in conventional and hybrid powertrains, with minor modifications; which allows optimizing production capacities and investment in technological development.
2. 48 VOLT “SOFT” HYBRIDIZATION
The 48-volt hybridization will allow hybridization of all types of motors with a very favorable cost-benefit ratio. The consumption and emissions simulations under the WLTC cycle completed by Schaeffler show that a hybrid level 0 - the simplest technically - achieves a saving of 3,8 percent in consumption and emissions (compared to a 12-volt micro-hybrid, with intelligent alternator and start & stop function) with an asynchronous pole or interleaved pole electric motor; and 6,6 percent with a permanent magnet synchronous electric motor.
3. FULLY VARIABLE DISTRIBUTION UNIAIR
Variable timing systems range from a simple camshaft phaser to the fully variable UniAir system. These elements optimize the combustion process and reduce fuel consumption and emissions.. Schaeffler has been mass producing the UniAir variable valve timing system since 2009, with more than three million units produced and constant optimization. A variant of the system has also been developed that can be easily integrated into existing engines. It is important that the engine, in general, and the turbocharging are adapted to the requirements of the fully variable valve train. With these premises, the UniAir system reduces consumption and emissions by 8,4% in the WLTC test cycle.
4. THERMAL MANAGEMENT
To maximize the efficiency of future powertrains, it is necessary to optimize the thermal balance of the entire system and its individual components and control heat fluxes. Schaeffler launched the first thermal management module for gasoline engines in 2011 and this system has not stopped developing since then. The second generation is a mechatronic module and this system will become more complex, and decentralized, in the future. Everything learned in the heat flows of hybrid vehicles will be used in the design of predictive systems, which ensure that all the elements of the vehicle work at the right temperature and receive heat or cold according to the needs of each moment. Thanks to this, the efficiency of the entire system will be increased and consumption and emissions will be reduced.
5. REDUCTION OF FRICTION
Bearings have already considerably reduced friction levels in accessory units by replacing plain bearings in camshafts, balance shafts, turbochargers and tappets. In the turbo, bearings can reduce cold friction by up to 80% and improve response, increasing efficiency by 2,5%, accelerating torque delivery and reducing mixture richness, minimizing NOx . The next step is to replace the crankshaft bearings with ball bearings, something that Ford is already working on. By simply installing a bearing on the first crankshaft bearing, the one furthest from the flywheel, a 1% reduction in fuel consumption has been achieved.
6. ELECTRICAL VARIABLE DISTRIBUTION
These systems allow the valves to be synchronized to adapt to all conditions of use of the engine. Unlike hydraulic camshafts, electrically actuated camshafts allow valve timing to be adjusted when the engine is stopped. During a start / stop sequence or when the vehicle is coasting (sailing), this system can prepare the combustion engine in advance for subsequent restart. As a result, less torque, friction and wear are required. Other benefits of the electric camshaft actuator are: a higher operating temperature range, faster and more precise actuations, and reduced oil pump workload. Thanks to all this, a reduction in consumption and emissions of 2 percent is achieved.
7. VARIABLE COMPRESSION
Schaeffler is working on electromechanical variable compression systems, to which he can apply all his experience in variable valve timing. Varying the compression ratio has a direct impact on combustion and therefore fuel consumption and emissions; and it is one of the few engine functions that has not yet been made variable. The classic compression ratio leads to a conflict of interest, to achieve a partial and full load efficiency compromise. And that commitment may, in many cases, not be enough to overcome the new emissions regulations.
8. CYLINDER DISCONNECTION
Three and four cylinder engines can also benefit from this functionality, which helps reduce CO2 emissions. The eRocker is an electromechanical system of simple integration that allows the selective disconnection of cylinders to reduce consumption and emissions. Schaeffler has also developed dual-mass flywheels and clutches with centrifugal pendulums to mitigate torsional vibrations caused by cylinder disconnection.
9. ELECTRONIC CLUTCH
43% of the cars sold in the world have a manual gearbox and although their market share is declining, their absolute number will continue to grow (2016 million manual boxes were produced in 40). They have in their favor their low cost, but in efficiency they have already been surpassed by modern automatic or automated checkouts. To take advantage of the opportunities offered by new technologies in reducing fuel consumption and CO2, it is necessary to automate the clutch of manual transmissions. Thanks to this, saving strategies such as “coasting” (circulating by inertia with the engine off) or recovering energy in deceleration and braking thanks to a level 0 or 1 hybridization system can be achieved. 8%.
10. ALTERNATIVE FUELS
Alternative fuels offer an additional approach, which goes beyond engine design to reduce emissions. Natural gas is already available and around 25% less CO2 than conventional gasoline. And in the medium and long term it will be possible to synthesize methane gas in a PtG process. Diesel engines will not be left behind and research is also being carried out on synthetic fuels based on a PtL (power to liquid) process. If the primary energy required during its generation also comes from renewable sources, such as wind or photovoltaic energy, fuels can be considered as CO2 neutral.