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48V – the solution to the advanced efficiency challenge?

Michael Nash talks to Punch Powertrain’s Gert-Jan Vogelaar about the various opportunities that 48-volt systems can provide

A study by market research and consulting firm Navigant Research suggests that global sales of 48-volt (48V) systems will hit nine million units by 2025, with the rising popularity of stop-start technology as a primary source of growth. Several suppliers could take advantage of this, including Punch Powertrain.

The Sint-Truiden, Belgium-headquartered company is currently developing a variety of transmissions with 48V applications, some of which are near completion while others are a nod to the future use of electrification in mobility.

Flourish in fuel economy

Punch Powertrain has two outlooks on 48V technology; according to Gert-Jan Vogelaar, Strategic Marketing Director, the company is running both short-term and long-term development programmes.

“At the moment, we have a few applications in preparation on our current transmission, which will be a P0 48V application,” he explained. “The first will be launched in 2017. Our new continuously variable transmission (CVT), the VT5, also has a P0 application that will be presented at the 2017 Shanghai Auto Show. That’s what we consider short-term.”

Every OEM will choose the most appropriate solution for their needs. They can either choose to sell PHEVs or BEVs that offer high efficiency gains, but come with much higher price tags, or they can sell more 48V solutions

As for the long-term, Vogelaar explained that Punch is developing a new family of transmissions. “The second,” he said, “will be a low torque version, and is being developed with a P2 48V system included. But it will be another couple of years before that’s in production.”

The main advantage that 48V systems bring to vehicle design is the fuel efficiency gain, an ever-more important issue when considering the increasingly stringent regulations surrounding fuel economy and emissions.

Take, for example, China. In this, Punch’s primary target market for its 48V transmission solutions, fuel economy is an extremely important aspect of developing new vehicle technology. “The same applies in other markets,” explained Vogelaar, “but it’s such a critical piece of the equation in China, because China is really aggressive in the way its moving forward with vehicle fuel economy. The legislation is set to get stricter by about 8% every year.”

Enabling freedom

When looking ahead to future fuel economy targets in China, Vogelaar thinks 48V systems could be essential in helping OEMs to continue selling models in the world’s largest automotive market. This is because each company must comply with fleet-wide fuel economy standards.

“The targets limit what OEMs can or cannot bring to market,” Vogelaar explained. “If the company doesn’t comply, it can’t bring a new vehicle into the market, or won’t receive permission for production capacity. The end consumer may not care so much about fuel economy, especially with fuel prices at the level they are now, but their options will be limited by legislation.”

All kinds of things can be done with the help of 48V systems. It opens the door for improvements in powertrain efficiency and reductions in emissions, but some of the most interesting benefits are found in additional systems outside of the powertrain

Electrification is considered to be one of the best ways to improve fleet average fuel consumption. As well as opting to use 48V technology, OEMs could try to sell more plug-in hybrid electric vehicles (PHEVs) or battery electric vehicles (BEVs). Recent statistics from the China Association of Automobile Manufacturers (CAAM) suggest that sales are rising sharply in both segments. In fact, a total of 507,000 so-called new energy vehicles (NEVs) were sold across the country during 2016, up from 331,092 in 2015.

Vogelaar does not consider the PHEV and BEV segments as a threat to future uptake of 48V technology. “Every OEM will choose the most appropriate solution for their needs,” he noted. “They can either choose to sell PHEVs or BEVs that offer high efficiency gains, but come with much higher price tags, or they can sell more 48V solutions. For us, that means we must work on a wide range of solutions, from conventional transmissions to 48V applications and pure electrics.”

No silver bullet

48V systems could also have their place in markets outside of China, Vogelaar suggested. Punch, he explained, has analysed the potential impact of 48V systems on nitrogen oxide (NOx) emissions – an issue that is currently particularly poignant in the European automotive market.

“We did an extensive investigation into whether a CVT system would be a better fit for reducing NOx than a dual-clutch transmission (DCT),” he recalled. “Our findings suggested that there isn’t much of a difference. But when using a 48V option, we found we could add torque without moving the combustion engine into working points with higher NOx emissions. This can result in a NOx reduction of approximately 20%.”

Beyond 2020, we could see some integrated solutions. For example, we might see transmissions designed from scratch with the actuation system based on 48V. This could potentially ensure dramatic improvements in powertrain efficiency

Although this is a significant reduction, Vogelaar acknowledged that NOx emissions need to be reduced even further to be in line with future European standards: “48V is therefore not a silver bullet. I don’t expect that OEMs will bring NOx emissions down within the limits required by legislation by using 48V systems alone, but it’s a step in the right direction.”

Higher voltage, lower price

As well as improvements to fuel economy and emissions reduction benefits, Vogelaar was keen to emphasise that 48V systems come at a low cost relative to PHEV or BEV systems. At the same time, the higher voltage in comparison to 12V systems opens up opportunities for efficiency gains elsewhere in the vehicle, not just in the powertrain.

“While automakers search for the most cost-effective solutions to continue reducing fuel consumption and emissions, as well as providing the electrical power needed for the ever-increasing feature sets of new vehicles, 48V electrical systems will play an important role,” explained Sam Abuelsamid, Senior Research Analyst at Navigant Research. “A 48V mild hybrid is estimated to provide 70% of the benefit of a high-voltage hybrid at 30% of the cost while boosting electrical power available in the vehicle from 2.5kW to 10kW.”

With this boost in electrical power, systems such as electric power steering, air conditioning and lighting could become even more efficient. This has already been demonstrated in some models, such as Audi’s SQ7, which features a 48V system to provide power for the air conditioning as well as an electrically driven supercharger.

“All kinds of things can be done with the help of 48V systems,” Vogelaar affirmed. “It opens the door for improvements in powertrain efficiency and reductions in emissions, but some of the most interesting benefits are found in additional systems outside of the powertrain. With this kind of synergy, the fuel economy gains could be significant.”

We designed transmissions that work without any electric oil pumps and could be used in mild hybrid configurations. This means they’re also set up for the inclusion of 48V applications

The full benefit of 48V systems in the powertrain will be realised beyond 2020, believes Vogelaar. “That’s when we could see some integrated solutions,” he predicted. “For example, we might see transmissions designed from scratch with the actuation system based on 48V. This could potentially ensure dramatic improvements in powertrain efficiency.”

Plug’n’play

As well as the technology’s more obvious benefits, such as fuel economy and acting as an enabler for other technologies, 48V systems do not require a dramatic change in vehicle design or manufacturing. Instead, OEMs need simply to switch their 12V system with a 48V system, and ensure that the other applications are compatible with the higher voltage.

When VT2 was launched almost ten years ago, few in the automotive industry were talking about the potential for 48V systems. However, there was development in the area of mild hybridisation. Punch Powertrain found itself in a sweet spot, “because we designed transmissions that work without any electric oil pumps and could be used in mild hybrid configurations,” Vogelaar noted. “This means they’re also set up for the inclusion of 48V applications.”

Including 48V technology in transmissions requires only minimal changes in terms of design, because Punch’s VT2 and VT3 transmissions were originally designed for a mild hybrid application, concluded Vogelaar. “They were basically ready for 48V systems from the start. We always had electrification in mind.”