Continuing QUBE/just-auto’s series of interviews with tier one component suppliers, we spoke to Christopher P. Thomas, Vice President and Chief Technology Officer, BorgWarner Inc.
What are the prospects for torque vectoring in mainstream and pure electric vehicles?
Torque vectoring, both mechanical and electrical, is being used by automakers as an effective differentiator. For example, the Golf GTI uses BorgWarner’s FXD technology to maximise torque-to-the-road in a front-wheel drive vehicle. In addition, 48V eAWD can be capable of torque vectoring as well as mild hybridisation. Mechanical torque vectoring systems can also add fun-to-drive performance to existing rear-wheel or all-wheel drive vehicles. The prospects are good for systems that improve safety and fuel economy while delivering fun-to-drive performance.
Has engine downsizing peaked?
There are some automakers that are still on the downsizing journey, while others are in the process of rightsizing.
Engine downsizing—turbocharging the engine to improve efficiency while maintaining or improving performance—has been a trend in the industry for many years. There are some automakers that are still on the downsizing journey, while others are in the process of ‘rightsizing’. New combustion strategies, such as the Miller cycle or cooled exhaust gas recirculation (EGR), change what displacement really means. New technologies, such as the eBooster® electrically driven compressor and eTurbo™ electrically assisted turbocharger, enable downsizing since the electrical assist function can make a small engine “feel” larger by improving low-end torque and transient response. In the end, it is about improving efficiency and fuel economy.
Is the next step really what you can do to recover more exhaust energy?
Extracting waste heat energy is one possible next step and fits with the core competencies of BorgWarner. There are several possible paths, but all include electrification. The Organic Rankine Cycle, where exhaust heat is used to boil a working fluid to drive a turbine and generate electricity, is one example for long haul trucks. Our emerging products, such as the eTurbo™ electrically assisted turbocharger and the eTurbocompound generator, can be used on many vehicle types to take waste heat and convert it into useful electrical power.
In terms of the compression ratio, there is always a trade-off with low-speed, high-load knock and part-load knock efficiency. Which technique will be used to raise ratios?
There are various ways to improve the combustion process, and automakers will use a combination of them going forward. Many automakers are developing gasoline engines with the Miller cycle, as well as engines with high levels of EGR. For instance, we have leveraged our extensive know-how in the field of turbocharging to develop a cost-efficient variable turbine geometry (VTG) turbocharger for the mass market that makes full use of the lower temperatures and exhaust gas enthalpy of that combustion cycle.
We are seeing a tightening of the particulate standards. What is the best solution?
Particulate standards vary based on regions of the world. In Europe, where particle number is regulated even at low temperatures, the best solution could be different than in the United States where the standard is particle mass. The good news is that combustion in gasoline direct-injected engines continues to improve, and we don’t expect that to stop in the near future. Today gasoline particulate filters and DI + PFI fuel systems are two ways particulate emissions are being addressed. In the end, one must balance fuel economy, performance, emissions and cost to be competitive in the market.
Are starter motors and alternators as we know them really on the way out?
Starters and alternators are evolving. For vehicles with a starter-based stop/start system, the starter has to be robust enough for 300,000 to 500,000 starts instead of only 10,000 for a traditional starter. This enhanced durability requires product-leading designs.
Starter/alternator-based systems are good options for providing smooth, silent engine starts while also transforming the vehicle into a mild hybrid. Our integrated belt alternator starter (iBAS) provides the hybrid functions of regenerative braking on decelerations and torque assist on accelerations in addition to the normal functions of an alternator. This provides 70-80 percent of the benefit of a full hybrid at 20-30 percent of the cost.
BorgWarner provides a spectrum of electrified technologies for a full range of propulsion systems, including mild hybrids, full parallel hybrids and pure electric/fuel cell systems. Advanced starters and alternators will still be part of this spectrum for the foreseeable future.
What will tomorrow’s turbochargers feature?
Tomorrow’s turbochargers will have improvements in aerodynamic efficiency, reduced heat loss and reduced friction.
Turbochargers are constantly trading off transient response against maximum efficiency. Advanced materials will continue to enable higher temperatures, lower cost and lighter weight, which can improve transient response. Tomorrow’s turbochargers will have improvements in aerodynamic efficiency, reduced heat loss and reduced friction. VTG for gasoline engines as well as variable compressor geometry will improve response, but also allow for new combustion strategies. Future turbocharger systems will have to overcome new emissions constraints that will probably prevent the engine from using scavenging, a strategy that adjusts engine valve timing to improve the low-end torque of the engine. The biggest change in the boosting system will be with electrification. The eBooster® electrically driven compressor and the eTurbo™ electrically assisted turbocharger are two technologies that can improve transient response without scavenging.
To what extent will future turbos use / need more development work on materials?
Higher exhaust gas temperatures are a result of operating the engine at stoichiometric air-fuel ratio for a larger portion of the operating range. We choose the right material to ensure that the turbocharger is not the limiting component.
Other materials can improve the rotational inertia and transient response of the turbocharger. Titanium aluminide, used in our Engineered For Racing (EFR™) product line, reduces rotational inertia by 40 percent and improves time-to-torque.
What will the average driver be driving in North America in terms of fuel, engine size, technology in 2030?
We have a fairly robust process for determining and tracking trending propulsion architectures. We have built cost and efficiency models of all of the likely architectures and understand what it will take to meet the regulations. Today, there are no regulations for 2030, so we have to estimate where we think the regulators are going.
Many vehicles will have much higher levels of electrification than today. This will be required to meet the fuel economy standards in the next decade. We have been predicting for a few years that HEVs will be replaced by mild hybrids and PHEVs. Some of this is because of the certification process, but mainly it is because of cost/value to the automaker.
There could be some regional differences in the mix of vehicles, driven by local regulations. Some cities are stating that some technologies may not be permitted. Instead of singling out specific technologies, we prefer a regulation standard approach, for example, only allowing a Euro 6 vehicle to drive in the city. This will provide a harmonised approach instead of a patchwork of standards.
Autonomous vehicles will likely have PHEV propulsion systems because of redundant braking and batteries.
Autonomous vehicles are still in the future, but we are planning for them now. These vehicles will likely have PHEV propulsion systems because of redundant braking and batteries as well as the need to provide higher utilisation rates required for autonomous/shared vehicles.
For those not living in large cities, vehicles will also be electrified but probably not fully autonomous. These vehicles will be connected but safe, with some degree of autonomy. For some customers, a vehicle’s propulsion system technology may be less important than connectivity, even if it delivers great performance and reduces emissions significantly. However, for others, the propulsion system will continue to be a means of expressing personal style and priorities.