We decided to mark the 20th anniversary of the International Engine of the Year Awards with a very special ‘Best of Best’ Award, a prize for what our jury of 70 of some of the most respected motoring journalists around the world believes is the most significant, most entertaining, and most relevant engine of the last 20 years. To decide who made the best engine of the last two decades, we asked our jurors to vote for a shortlist of powertrains that have won the overall International Engine of the Year title since the Awards began in 1999. It’s a shortlist comprising some of the best power units ever made, from the inaugural International Engine of the Year – Toyota’s 1-liter, four-cylinder – to Ford’s own 1-liter that won the overall title three years in a row from 2013.

Also in the mix for the Best of Best honors was the 2003 winner, Mazda’s rotary Renesis, along with Fiat’s 875cc two-cylinder, plus VW’s 1.4 liter Twincharger that won in both 2009 and 2010. Toyota’s 1.5-liter hybrid won in 2004, meaning it went head-to-head for the Best of Best prize with numerous contenders from BMW, the most successful brand in the Awards’ history. The Munich-headquartered company has won the overall Awards title a record seven times with its 5-liter V10, its 3.2-liter straight-six, its 3-liter twin-turbo, and its 1.5-liter hybrid that won in 2015. And so what we witnessed was a true David and Goliath battle: 875cc Fiat takes on BMW’s 5-liter.

But the outcome of the Best of Best competition may at first come as a surprise to some. Honda’s pioneering 1-liter IMA hybrid from the year 2000 didn’t really feature in the results, while the aforementioned BMW i8 1.5-liter that brought plug-in hybrid-power to the supercar was actually beaten by its near legendary 3.2 straight-six sibling. No, the jury voted the Ferrari 3.9 V8 the overall Best of Best engine of the last 20 years!

The Italian biturbo, which also won a further three Awards this year by topping the Performance Engine category, the 3-liter to 4-liter category, and taking the overall International Engine of the Year title for a third consecutive year, has been named the greatest engine of the International Engine of the Year Awards era. Why? At first, you could be forgiven for thinking its triumph is because it emits enough power to put a smile on anyone’s face. Its success could also be the fact that the V8 emits an incredible sound, or that it’s a rare beast in that it’s a forced-induction engine that thrives on revs. It’s ‘efficient’ too: a so-powered Ferrari 488 can sip just 11.4 l/100km (20.6mpg) compared with the 4.5-liter-propelled 458 predecessor that guzzled
0.4 liters more gasoline to travel the same distance – and yet the bigger engine produces 68ps less. However, the main reason why this 3.9-liter V8 has been so successful is because Ferrari took a risk when it downsized its engine and decided to add a pair of turbos.

It is a fact that a Ferrari with anything other than a spectacular engine is set to become commercially unloved. Beautiful styling? Check. Involving handling? Check. Dull-sounding engine, that doesn’t have much performance, and isn’t fun to rev? Oh dear!

When Ford decided to put a 1-liter, three-cylinder unit under the hood of its Focus, it wagered the equivalent of US$100. Had its gamble not worked, the US giant had other engines to call upon – and indeed already available in that very model. But when Ferrari downsized and added turbos to the engine of its biggest seller, it arguably bet the success of the entire company! That the gamble worked signaled to the entire car industry that downsizing and turbocharging – and no doubt plug-ins et al. – are acceptable to even the most discerning of car buyers. And for that reason, Ferrari deserves the Best of Best Award.

As the automotive industry undergoes arguably its biggest ever step change, Ben Gale, technical sales engineer, Horiba MIRA, discusses the pursuit of efficiency.

The automotive industry is going through one of its biggest transitions as the evolution from internal combustion engines (ICE) to electric vehicles (EV) enters a new age. As social and political pressures gradually increase, the need for an all-electric range (AER) automotive industry grows, painting an ever-popular picture of the future of automotive.

The current state-of-play involves OEMs and their desire to increase the energy available within EVs; this results in the need for increased battery capacity and energy optimization. In order to achieve this, OEMs rely heavily on cell chemistry improvements to aid the energy density or power density of their battery packs. Another option to gain energy is to look at how efficiently the system or vehicle operates. Horiba MIRA’s efforts will be to focus on this newer approach by offering OEMs Total Energy Management (TEM) analysis and development.

As the cell chemistry becomes more energy dense, the requirements for greater levels of safety and state-of-the-art cooling systems grow. Furthermore, long-term issues such as material sustainability, packaging and recyclability must take center stage as the industry manages the transition from ICE to hybrid and EV.

Improving the public perception and validity of EVs on our roads relies heavily on the new development in cell technologies and our ability to extract, use and reuse energy efficiently. Global automotive bodies and government officials are now identifying efficiency as a key attribute for new electric vehicles (NEV). For example, within the Chinese automotive sector lies the NEV point system, rewarding EVs on competitive statistics and the amount of distance traveled per kilowatt-hour on board.

Horiba MIRA has been working heavily with prototype EVs for nearly two decades and has led developments in new techniques, such as providing holistic TEM offerings to customers. This includes an internal, dedicated Energy Efficiency Group consisting of experts across the EV technical areas – electrical, software, thermal and mechanical.

The emphasis on battery range presents many challenges, one of which is understanding the actual performance and characteristics of the battery cells. Horiba MIRA’s new Advanced Battery Development Suite (ABDS) enables us to carry out such activities at extremely high resolution and accuracy. With the ability to characterize cell performance, the technical boundaries continue to be pushed and result in more usable energy and consequently EV range. Horiba MIRA is also using the ABDS facility to investigate the details of cell aging mechanisms and how to keep cells within the ‘sweet spot’ – to lower the degradation and increase the durability of these cells.

The ABDS facility gives us the capacity to exercise modules and packs with up to 1,000V, 1,200A and charge at 600kW. These capabilities enable us to future-proof the facility for the next five years and verify pack performance and the design of future EVs. As we look at increasing performance and range, other components of a battery, most noticeably battery cooling, must be developed to ensure that everything runs at the most efficient level. Horiba MIRA’s ABDS facility, climatic wind tunnels and thermal testing equipment provide detailed analysis of battery, powertrain and cabin cooling to ensure maximum gains are made by its customers.

There are also other challenges we face when we look at range – driving style, traffic and additional weight produce both positive and negative outputs on battery life. Ambient conditions also play a large part in the EV world. From the beginning of EVs it was soon established that cold weather would play a significant role in the reduction of range. Therefore, we are now seeing more focus for OEMs to increase the AER at the temperature extremes (both hot and cold).

As OEMs look to deliver EVs with increased performance and software capability, the traditional engineering and attributes seem to fall by the wayside. Traditionally, OEMs would develop the vehicles based on knowledge from previous platforms and their test data legacy. Development programs would typically contain the refinement of traditional attributes such as dynamics, NVH and durability.

However, an abundance of new entrants and a lack of OEM legacy data has resulted in a shift of focus toward using software and simulation for increased performance. This may leave devastating holes within the vehicle development cycle as traditional engineering was, and still is, required. Horiba MIRA is supporting its customers with both traditional and non-traditional engineering techniques, strengthening the idea of a holistic approach.

With energy efficiency at the forefront of the automotive industry, OEMs continue to search for new ways to quantify energy usage. Previous schemes were based on the range of a vehicle, and lacked incentive to use their energy wisely. Schemes such as the NEV point system incorporate the measurement of TEM and give OEMs a strong focus on improving the overall energy efficiency in order to gain large incentives and remain competitive.

Millbrook is in the process of installing 12 new battery test cells at its UK base, each able to test automotive battery packs up to 1,100V, 1,400A, 750kW over a temperature range of -40°C to +90°C. These will be controlled via Millbrook Revolutionary Engineering’s automation system, REPS.

Toyota has unveiled the second iteration of its Project Portal hydrogen fuel cell electric Class 8 truck.

The capabilities of the new Beta truck are said to significantly exceed that of the Alpha demonstrator vehicle revealed in 2017, including increasing the estimated range to more than 300 miles per fill.

Versatility and maneuverability have also been improved with the addition of a sleeper cab and a unique fuel cabinet combination that further increases cab space without increasing wheelbase.

For both the Beta and its predecessor, Ricardo assisted Toyota with much of the engineering. This included systems integration and packaging, including the fuel cells, power electronics, hydrogen tanks, cooling systems, batteries, electric motors and transmission.

Many of the ancillary systems that are traditionally driven by the engine were also electrified, including the air compressor, power steering and HVAC system, the controls of which required integration into the vehicle’s J1939 CANbus.

Crucially, both the Alpha and Beta vehicles were constructed by Ricardo at the workshops of its Detroit Technical Center in Bellville, Michigan.

With a gross combined weight capacity of 80,000 lb, the +670hp Alpha truck produced 1,325 lb/ft of torque from two Mirai fuel cell stacks and 12kWh of battery.

The Project Portal Beta vehicle maintains these torque and horsepower numbers while also extending the range of the vehicle by 50% to in excess of 300 miles between hydrogen refills.

“The Ricardo team is pleased to have been able to continue our successful collaboration with Toyota on the very important Project Portal heavy-duty zero-emission fuel cell electric truck demonstration project,” commented Chris Brockbank, VP of vehicle engineering at Ricardo.

“The Beta Project Portal vehicle is an impressive advance over its Alpha predecessor, offering practical design improvements in addition to its very practical 300-plus mile range, which makes it a capable ZEV option for drayage operations.

“We look forward to working with Toyota in the completion of the real-world drayage testing, and to seeing the results of the project which, I believe, may well inform the future vision of heavy-duty transportation.”

 The Advanced Propulsion Centre (APC) has awarded £35m (US$45.3m) to three UK-based low-carbon automotive powertrain projects that could potentially reduce CO₂ by three million tonnes and create or safeguard nearly 1,800 UK jobs.

With a total value of more than £70m (US$90.7m), including both government and industry investment, the projects are also expected to enhance the UK’s supply chain and competitiveness in the development of ultra-low emission vehicles, and upskill UK workers.

Companies involved will include Hofer Powertrain, Aston Martin, Ceres Power, Nissan, Artemis Intelligent Power, Danfoss and Robbie Fluid, covering a broad range of industries.

Artemis Intelligent Power in Greater London will focus on non-mobile machinery, which contributes 10% of all NOx emissions and 11% of all PM 10 emissions.

This project aims to introduce a disruptive technology to the off-highway vehicle sector, which will reinvent hydraulic power for the digital age. It has the potential to reduce fuel consumption and CO₂ emissions of some off-highway vehicles by more than 50% when fully developed, and will help anchor future R&D and manufacturing capability in Scotland.

Ceres Power will work with Nissan to develop a compact, high power density, solid oxide fuel cell specifically designed to extend the range of electric light commercial vehicles. This program addresses commercial vehicles, one of the most challenging aspects of the transportation system to decarbonize, and will demonstrate the scalability of the technology to other automotive segments.

Hofer Powertrain and Aston Martin meanwhile are developing a new generation of technically advanced e-motor and inverter modules, which will be manufactured in the UK, for future high-performance vehicles. This project is expected to build the UK’s e-mobility skills base and improve productivity.

Ian Constance, chief executive of the APC (pictured), said, “The challenge of lowering emissions is shared by the entire automotive industry, and includes all areas of the sector. This latest round of APC funding highlights the broad range of vehicle types that will benefit from developments in low-carbon innovation, with successful applicants developing technologies for commercial and off-highway vehicles, as well as the wider e-mobility industry. We expect that this approach will help to create and safeguard jobs across the UK automotive sector.”

Niall Caldwell, MD at Artemis Intelligent Power, commented, “This UK funding will enable us to develop digital displacement technology as a major component in the US$3.5bn off-road equipment market. It’s not enough to invent these technologies in the UK – we also need to manufacture them here and export around the world. This announcement paves the way for the UK to take the lead in a low-carbon technology with global potential.”

Ceres Power CEO Phil Caldwell said, “This APC-funded project will develop an automotive-specification fuel cell range extender. It is the next step toward increasing the technology and manufacturing readiness of a compact, robust, fast-response SOFC (solid oxide fuel cell) stack for high volume production.

“APC funding enables Ceres and its partners, who are responsible for the automotive application, to jointly engineer a SOFC solution that contributes to a low-carbon future.”

William Hartley, MD at Hofer Powertrain UK, added, “The grant awarded to Hofer Powertrain and partners under APC9 enables us to anchor the design and manufacture of advanced electric and hybrid drive units, power electronics and control software in the UK, alongside our transmission design and manufacture capability. It would not have been possible without the support of APC and BEIS (Business, Energy and Industrial Strategy).”

Mahle Power has officially inaugurated its state-of-the-art £8.3m (US$10.8m) vehicle development and testing facility at its Northampton site in the UK.

The center, which benefited from a £2.1m (US$2.7m) investment from SEMLEP’s Local Growth Fund, will enable manufacturers to develop and test their vehicles on a new 4WD chassis dyno while being subjected to a wide range of altitude and climatic conditions.

The auto industry must ensure that all new vehicles comply with RDE regulations coming into force in September 2019. The new rules dictate that all vehicles certified for sale in the UK must achieve compliance under real-world driving conditions. This means testing the vehicle under a wide range of conditions, including driving at high and low altitudes, varying temperatures, with and without payloads, and on all road types.

Mike Hawes, SMMT chief executive, commented, “SMMT is delighted to see Mahle Powertrain open the UK’s first dedicated RDE test facility. Together with the WLTP lab test, RDE is part of the toughest emissions testing regime in the world.

“It provides clear evidence that the automotive industry is delivering on its commitment to cleaning up our air while providing motorists with more realistic emissions and fuel consumption information.”

UK Business and Industry Minister Richard Harrington said, “Technology is changing the way people, goods and services move around the country, and through our modern industrial strategy we are ensuring the UK remains the home of the latest innovations in transport.

“Mahle Powertrain’s real driving emissions test center is the first of its kind in the UK and with its dedicated workforce, will ensure the automotive industry champions clean and sustainable growth.”

During the official opening event, visitors received a tour around the facility including the center’s climatic and hypobaric test chamber, installed to deliver highly accurate and repeatable emissions results and data.

Visitors were also given the chance to hear from senior Mahle engineers who explained how the center enables the company to carry out all elements of the RDE testing regime with the opportunity to bring further RDE-related work back to its laboratory to save development time and cost.

Simon Reader, engineering director at Mahle Powertrain, stated, “Our new facility puts Mahle Powertrain at the forefront of real driving emissions development and, for UK-based manufacturers, it means that vehicles can be thoroughly tested to the highest standards without leaving the country. This will shorten lead times and costs, helping the UK to retain its reputation for automotive engineering excellence.”

Toyota’s chief engineer for the Supra reveals the evolutionary journey behind the marque’s new sportscar

Forty years on from the production of the first Supra model in 1978, the hotly anticipated, all-new fifth-generation model has been revealed in prototype form. It’s been experienced dynamically at the famous Goodwood Festival of Speed hill course and showcased statically at a special invite-only event for Supra enthusiasts.

At all times, chief engineer Tetsuya Tada has proudly accompanied his ‘new baby’ and been eager to reveal tantalizing glimpses into its development and specifications. Here’s what he had to say about it.

How long have you been working on the Supra project?
Since 2012, so nearly seven years – a long time. The normal cycle for car development is around three years but with this project we wanted to make absolutely sure it was right.

How does it feel to finally reveal the prototype after such an extended development program?
All I can say is that I’m just so happy that we’ve made it to this point. I’ve finally been able to reveal the car to the UK; it’s the happiest day of my life. And to drive it up the hill at Goodwood was a really exciting experience.

You introduced the GT86 as your passion project. Did the Supra project arouse similar feelings?
Of course. It was imbued with a lot of passion. Before the GT86 arrived, Toyota had not produced a sports car for a while, so there was a lot of ground to catch up. But for the Supra project we already had the experience from developing the GT86 and were able to start from a much higher level. This meant we were aiming for a much higher level in the finished car.

Were you trying to create a big brother for the GT86?
Akio [Toyoda – president, Toyota Motor Corporation] has always said that as a company he would like to have ‘three brothers’, with the GT86 in the middle and Supra as the big brother. So we’ve tried to aim for the Supra to offer an overwhelming superiority in all attributes. For example, people were happy that the GT86 had a very low center of gravity, but the Supra has an even lower center of gravity, and its body rigidity is twice that of the GT86.

It’s actually the same level of rigidity as the Lexus LFA supercar, and it has been achieved without using carbon fiber so we could keep the price point at an affordable level. That was the most difficult thing to achieve. But I’m pleased we were successful because when I was sitting in the queue to go up the hill at Goodwood, I was surrounded by all these amazing supercars and thinking: ‘This is the cheapest car in the line by a long way – probably about a 10th of the price’ – but we got the biggest cheer!’

The track is also wider, of course. But it may surprise people to know that the new Supra has a shorter wheelbase than the GT86. The car was developed with a specific ratio of wheelbase and track in mind, and I think we’ve been able to achieve the balance that we were looking for.

How do you think the new A90 will be received by hardcore Supra fans?
I’m really looking forward to hearing from them, actually. Thinking back to the introduction of the GT86, some owners of classic AE86 models were quite hard to please and were very critical of the new car. So it may be similar with this car. I know there are hardcore owners of the previous generations out there and it may be difficult to convince them just by introducing a new car.

But I have an open stance and want to offer my respect for the older Supra models. In turn, I hope the owners will be open enough to see what the new model is all about, even if it takes them some time to fully accept it.

As this is the fifth-generation Supra, can you give us five things that you would like Supra fans to know about the car?
First of all, the Supra has always had an in-line six-cylinder engine, and of course we have that with the new car, too.

Secondly, all generations had a front-mounted engine and rear-wheel drive; that is also the same here.

I think for number three I would like to point out its design. We’ve taken cues from the A80 [fourth-generation Supra] and, although the design is not the same, we carried elements over so that when people look at the new car they can tell immediately that it is a Supra.

Number four is that if you look across the previous generations, each of them have been exciting in their own right and in their own era. We wanted to achieve the same thing with this new-generation car, and I believe that when it goes on sale next year it will be the most fun-to-drive car in its class.

Looking at the current automotive industry, the talk is all about autonomous driving, electrification and artificial intelligence. What that’s doing is giving rise to a lot of strict regulations, and that limits our capacity to make emotional sports cars; it’s getting much more difficult to do that. So for the fifth point, I think the new Supra will be the last gift from Toyota to those who enjoy hearing the pleasing sound of a pure petrol engine at high revs.

Those are my five highlights, and I hope that people will be able to enjoy the new Supra for a long time to come.

Ashley Watton, Cummins’ director for on-highway business Europe, discusses the viability of Euro VI repower solutions

While electrification may be in the headlines, an alternative route to achieve cleaner air quality in our cities is gathering momentum – the repowered bus. In a bid to speed up the adoption of Euro VI clean diesels, Cummins trialled the benefits of repowering an old bus – a 1962 Routemaster RM1005 – ready to meet the 2019 London ultra-low emission zone standards (ULEZ).

The bus sports a new, clean, Euro VI diesel engine and exhaust system, which is supported with the latest Connected Diagnostic technology from Cummins.

Among other work, the Routemaster has been used on the heritage bus route between Tower Hill and Trafalgar Square in the UK capital, delighting tourists and locals alike. The venerable appearance of the bus is deceiving –  installed under the skin is the latest four-cylinder B4.5 engine built at the Cummins Darlington plant. This means it’s as clean as any of the newest diesel buses working in London today – not bad for a bus that entered service in 1962.

One of the reasons we decided to look into a repower solution is the ability to significantly extend the life of an older bus by upgrading to the latest Euro VI emissions standards without the higher costs associated with buying a new bus. Moreover, this initiative will enable bus fleets to accelerate their adoption rate of cleaner Euro VI powered-vehicles, particularly with many UK cities looking to introduce low emission zones, following London’s example.

Selecting one of the oldest buses available also demonstrated how far this technology can be stretched – if a 1962 Routemaster could be repowered to be as efficient as the newest buses on the market, then it is clearly possible to apply this technology to a vast array of buses that no longer meet current, more stringent Euro VI emissions standards.

When the project started, we had a heritage bus, owned by Sir Peter Hendy, meeting only Euro I standards with an old six-cylinder engine. By the end of the project, the bus met the requirements for Euro VI and boasted a smaller, lighter four-cylinder engine. To do this we had to completely re-engineer the entire powertrain. This was achieved by installing a new engine, upgrading to a more efficient transmission and downsizing to a Cummins B4.5 clean diesel engine. The highly compact 4.5-liter and its integrated exhaust aftertreatment made it an ideal fit for the small engine compartment and allowed our engineers to undertake the repower without altering the external appearance of the bus. We also made a few improvements inside with the driver dash panel and pedals modernized to align with the new engine technology.

The bus also comes with another technological surprise. It features Cummins Connected Diagnostics, an integrated telematics system that beams data over the airwaves to a laptop or phone making it possible to monitor the health of the engine and show where the bus is located. The system maximizes bus uptime, by alerting the operator when engine servicing may be due and proactively highlights any fault so it can be checked out at a convenient time.

This Euro VI repower program can cover many different bus models and emissions levels. Depending on the age and condition of the bus, each repower project will be individually evaluated: it could range from a simple engine aftertreatment replacement, up to a complete powertrain refurbishment and fabrication work.

With the 4.5-liter engine, ratings extend up to 210bhp, which was only attainable with our 6.7-liter engine a few years ago. More importantly, it could extend bus life by seven or eight years with lower servicing costs. It’s not ‘an engine in a box’ but a complete repowering option. Although it’s impossible to give precise pricing as every installation will be different, operators should expect the repower to be about 20% of the cost of the vehicle when new.

Cummins is engaging with a broad spectrum of bus manufacturers and repower delivery agents to ensure every opportunity for Euro VI bus repowers can be realized with a Cummins Installation Quality Assurance (IQA). The repower installation will be developed in collaboration with Cummins and pre-certified with an IQA to the same level as a new vehicle design installation.

Repowered systems like this go through the same emissions certification and compliance requirements as that of a new engine, including transient and steady state test cycles, hot and cold transient test cycles, onboard diagnostics stringency, and in-service emissions life requirements.

The Cummins repower features an integral stop/start system to eliminate fuel used during idling by automatically switching the engine off when passengers are boarding or alighting. This can reduce the fuel consumption of a double-deck London bus by up to 8% when operating on a duty cycle of up to 16 hours per day.

Compared to an earlier Euro V conventional double-deck bus, the Euro VI fuel saving can reduce the operating cost in the range of £1,500 (US$1,955) to £2,500 (US$3,258) per year, making a significant impact to offset the cost of the repower. The lower fuel consumption also reduces the carbon footprint of the bus, with the potential to eliminate around 4-6 tones of CO₂ emissions each year from the vehicle.

Cummins Euro VI bus engines are compatible with running on B20 biodiesel or HVO renewable diesel. Compared with conventional fossil-based diesel, HVO offers the potential to reduce greenhouse gas emissions by 40 to 90% over the total lifecycle of the fuel, depending on the feedstock.

In summary, repowering has great potential to not only extend the life of an existing bus fleet, but to help improve air quality and reduce greenhouse gas emissions. It also enables the bus fleet market to benefit from fuel savings over the extended life of their vehicles.

However, more importantly, as the bus industry responds to the requirement for energy diversification it demonstrates that diesel has an important place in future power solutions alongside Cummins initiatives with hybrid, natural gas and battery electric powertrains.

As socio-political needs move quicker than ever, APC predicts a shift to whole-life environmental regulation and increased fragmentation of powertrain strategies

“After decades of evolution, vehicle technology is now at an inflexion point, changing faster than at any time in the last 100 years. That presents a tremendous opportunity for British businesses,” said Advanced Propulsion Centre CEO Ian Constance.

“This new analysis will help investors, innovators and government understand which technologies need to be developed as we drive at increasing speed to low-carbon transport, helping them make the decisions that will ensure the UK remains a global player in 2030’s US$1tn global market for low- and zero tailpipe emission vehicle technologies.”

As well as providing insight into the innovations required to deliver a step-change in vehicle emissions, APC predicts fundamental changes that will have a dramatic impact on the way automotive innovation is planned an evaluated. The most significant of these is the move from vehicle-level regulations to a focus on end-to-end sustainability.

“Most future powertrain options require substantial battery capacity, but the environmental impact of these systems cannot be controlled through traditional vehicle-focused regulation,” explained the APC’s head of technology trends, Dave OudeNijeweme.

“This means a different approach to decision making is required, even before we consider trends in the availability of raw materials. The Roadmap will be of value to decision makers across many sectors, providing insights into areas of growing complexity and illuminating the impact of new business models such as mobility as a service.”

With 10% of UK manufacturing automotive, supporting the commercialization of high-impact innovations will help British businesses – from technology innovators and suppliers to vehicle manufacturers – grow profitably in a fast-changing global market.

“Through the Advanced Propulsion Centre, we are able to facilitate investment of £1bn (US$1.3bn) of government and industry money to help British businesses validate and commercialize their innovations. New technologies disappear because the UK has traditionally lacked the market pull innovators need to bridge this most challenging phase of innovation,” added OudeNijeweme.

As would be expected, the electrification of future powertrains will feature prominently, but “this should not be confused with a prediction of mass adoption of full EVs,” emphasized OudeNijeweme.

“What we see is the rapid introduction of a diverse range of electrification technologies, including mild hybrids, full hybrids, plug-in hybrids, fuel cell electric vehicles and battery electric vehicles. Clearly the majority of these still rely on internal combustion engines so continuing advances in that area remain important.”

Growing electrification presents new approaches for internal combustion engine design. While some vehicle manufacturers will achieve ultra-low emissions by developing increasingly sophisticated IC engines, others may choose to simplify engine design by focusing on optimization of a narrow operating region.

This will enable greater levels of synergy between the ICE and powertrain electrification and permit further optimization of the engine, such as the use of novel combustion cycles.

Very high levels of integration are also predicted in electric drives, with the e-machine, transmission and power electronics coming together to create a single, lightweight, tightly-packaged and lower cost unit with greatly reduced complexity.

“These units operate in an exceptionally demanding environment that is a great example of the critical importance of ‘automotive grade’ to ensure durability,” noted OudeNijeweme.

“Part of the role of the APC is to help innovators from outside our industry understand these requirements and to set up programs and partnerships that lead to the exceptionally robust yet lightweight and affordable technologies our industry excels at.”

Andrew Dimelow, principal engineer at Cummins Turbo Technologies, outlines the benefits of conjugate heat transfer (CHT) analysis to predict turbocharger stage performance and component temperatures under select steady and transient operating conditions

Cummins Turbo Technologies routinely uses computational fluid dynamics (CFD) to predict turbocharger behavior and generate performance maps. Typically, this type of analysis is solely concerned with analyzing the aerodynamics of the respective stage and does not consider the effects of thermal exchange across neighboring components.

However, with advanced modeling capabilities and access to greater computational resources, it is possible to build a comprehensive CHT model of an entire turbocharger. This multi-domain model is inclusive of housings, core components and stage cavities and provides a tool for generating temperature predictions by simultaneously solving conduction and convection. Of particular interest is the opportunity to explore thermal effects on stage performance under both adiabatic and non-adiabatic conditions. In addition, this analysis approach enables the generation of wetted surface thermal loads which can support subsequent higher resolution damage and thermal mechanical fatigue (DTMF) analysis.

The aerodynamic department at Cummins Turbo Technologies carried out three unique studies which demonstrate the broad application of this analysis approach. Study one was a comparison of adiabatic and non-adiabatic HE200VG compressor performance.

A CHT model of a Cummins non-water cooled HE200VG turbocharger was generated in order to investigate compressor stage performance at several running points when considering heat transfer across the assembly. Efficiency was calculated under adiabatic, non-adiabatic and a ‘heat’ condition where the compression is assumed adiabatic but the calculation is inclusive of heat transfer both pre- and post-compression. The analysis, therefore, was capable of breaking down enthalpy change intervals in the compressor stage.

The results showed compressor efficiency curves at three speeds, and showed a greater difference between peak adiabatic and peak non-adiabatic efficiency at the lower speed (~3%). This value reduced to ~0.7% at the high-speed condition. If the heat efficiency can be considered a truer value of the actual compressor efficiency, the results suggest at lower speeds the adiabatic efficiency is more accurate whereas at higher speeds the non-adiabatic efficiency is more accurate.

This supports the understanding that at lower speeds, temperature effects have a greater impact on efficiency. An enthalpy breakdown shows that less heat enters the compressor stage at the higher speed condition, and the energy that enters before the compression is likely to be as a consequence of the compression itself.

Study two analyzed absolute temperature predictions of HE200VG at rated steady operation and transient Hot Shutdown Event (HSE). A CHT model of a non-water cooled HE200VG turbocharger was generated in order to predict temperatures at critical bearing housing locations under a rated steady operating which initiated a transient HSE. A thermal survey of the turbocharger was completed on an engine test in order to understand the level of error present in the CFD model at both conditions of interest.

Immediately disengaging an engine following a period of high power operation can result in an HSE due to high thermal gradients between housings which causes a thermal soak across the turbocharger. This can generate temperature spikes at sensitive locations and repeated HSEs can lead to oil degradation, component wear and ultimately, reduced service life.

Having a CHT model to predict absolute temperature spikes resulting from an HSE is of significant value as it can enable the evaluation of multiple design concepts.

Results demonstrated CHT steady temperature predictions were an average of 1.6% higher across the piston seal ring thermocouples, an average of 7.9% higher across the turbine side journal bearings, and an average of 1.8% lower across the compressor side journal bearings. CHT maximum HSE temperatures were an average of 9% higher across the piston seal ring thermocouples, 1.4% lower across the turbine side thermocouple locations, and 9.7% lower across the compressor side thermocouple locations.

The level of agreement between the CHT model and thermal survey gives a useful degree of confidence in the purpose of evaluating different design concepts under equivalent modeling assumptions.

Finally, study three looked at the generation of transient thermal loads for increased resolution DTMF analysis of HE300WG turbocharger. DTMF analysis is a finite element analysis (FEA) modeling technique which can predict material failure rates due to cyclical thermal loads and is an important stage in the design process of turbocharger components.

A standard approach to preparing a DTMF analysis utilizes a combination of transient thermocouple data from an Accelerated Thermal Cycle Test (ATCT) and constant heat transfer coefficients in order to generate thermal boundary conditions. Thermal and structural FEA analysis is subsequently performed over a number of ATCTs to generate inputs for the DTMF predictions. The accuracy of the DTMF analysis is therefore significantly influenced by the accuracy of the absolute temperatures and thermal gradients calculated in the thermal FEA model.

CHT analysis can be used to simulate the transient ATCT in order to generate increased resolution thermal inputs on stage wetted surfaces and will export individual nodal heat transfer coefficients and wall adjacent temperatures at each thermal load step.

Results of the tests showed that CHT temperatures compared well against thermal survey for the ATCT duration. This gave a reasonable level of confidence in the generated thermal loads to be applied to the DTMF analysis. The CHT-supported DTMF analysis vastly improved the predicted failure cycles with the average prediction ratio calculated as 1.65 as opposed to 465 using the standard DTMF boundary conditions.

This study underlines the importance of the suitability of thermal loads to the accuracy of predicted failure cycles from a DTMF analysis and demonstrates a valuable application of conjugate heat transfer analysis.

For Cummins, the paper demonstrates an approach for applying CHT analysis to a range of steady and transient operating scenarios for predicting turbocharger performance. Results from all three studies provide confidence that CFD can be introduced into the design cycle of a turbocharger with respect to thermal management considerations as well as aerodynamic optimization. This gives the opportunity to arrive at optimal designs faster with reduced requirement for costly physical testing.