Both of those products are described as bridge or transition technologies to help reduce carbon emissions for vehicles and other equipment in the run-up to 2050, when the UK has pledged to go net zero.
First, Cummins reported that an unnamed vehicle OEM is planning to launch an internal engine combustion vehicle in 2025-2026 running on hydrogen rather than diesel. What is envisaged is a spark-ignited engine using a conventional engine block, with an engine head adapted for hydrogen. (Last year it launched the concept, including the 15-litre X15 engine with heads for diesel, natural gas or hydrogen gas fuel; US versions will burn gasoline or propane.)
At a technical press day in Huddersfield on 8 June, Cummins shared these figures: a 15-litre, 444bhp hydrogen-powered engine offering 500 miles of range from 80kg of hydrogen stored at 700bar. It said that this vehicle would be 2,500 lbs (1,134kg) heavier than a comparable diesel Class 8 sleeper cab truck, referring to the American designation of an artic, and attributed the weight premium to the H2 tanks.
Engineering issues in the project include the lower calorific value of hydrogen (even when highly compressed), material choices – as hydrogen can cause embrittlement of vulnerable materials – and the inevitable production of NOx during combustion. For the latter reason, a relatively simple emissions aftertreatment system, such as employed for natural gas trucks, is expected. Incidentally, the hydrogen engine is not completely carbon free: it is billed as producing 97-99% less CO2 than a diesel engine, as a little oil is inevitably burnt during combustion.
Development of this engine concept has been supported by work by the Brunel project, an R&D consortium including Cummins (based in Darlington), BorgWarner, Johnson Matthey and Zircotec, which has received £14.6m of government funding. In the UK, Ricardo has supplied the project with a one-off test engine, following its own work at the University of Brighton. Worldwide, Cummins claims to have logged 3,000 test hours.
It’s a popular idea. In unrelated news, the UK government announced in May that an R&D consortium, led by BorgWarner, with Mahle, Cambustion and Hartridge, had won £9.8m of public funding for Project Cavendish, to convert heavy-duty diesels to run on hydrogen.
Helping to boost combustion in the hydrogen ICE will be a high-performance turbocharger. Ideally, it would be a single-stage, variable-geometry turbocharger, but a two-stage unit is more likely, as it will need to provide the right transient response, company experts said.
A new turbocharger for hydrogen fuel cells which is claimed to help increase power capacity is also in development. Heavy-duty applications would require large fuel cells; the more air pumped into the cell, the more oxygen is available to combine with hydrogen to make energy. Early fuel cells used air blowers, but eCompressors produce much higher air pressures. To that end, a 48V DC 12kW eCompressor is in development.
Of course, that comes at a cost in terms of energy consumption. This is where a turbine in the exhaust stream can recover kinetic and thermal energy, reducing the total energy drain. Such a product is now being developed as part of a collaborative R&D programme, Project Trident (with partners the University of Bath, Holtex and Aeristech). A first demonstrator has been developed, and a second is due by the end of the year, when the project winds up.
Cummins contends that a 48V DC model rated at 45kW capacity can regenerate 25kW of energy from the waste stream, providing 70kW of energy to facilitate a more powerful fuel cell than currently offered, theoretically 250kW. It says that this would be possible despite a much lower combustion temperature (100°C compared to 650°C), as well as a more humid gas stream. Still, the savings could offer 8% overall fuel savings, Cummins reports. 48V e-turbos in wastegate and variable-geometry designs are in development.
The company offers turbochargers in three segments: 2.5-16-litre wastegate, 5-17-litre variable geometry – both for vehicle applications – and larger variable geometry versions up to 100-litre capacity for power generation and marine applications. Cummins reports it has improved wastegate turbocharger efficiency performance by 12% in the past decade, thanks to developments such as abradable compressors, improvements in aerodynamics and rolling element bearings. In the same period, variable-geometry turbocharger performance has improved by 9%, thanks to those elements and multi-clearance shroud technologies. But, it warns, design improvements are approaching the theoretical maximum.
Cummins’s turbocharger factory refurbishment, internally referred to as Project Jupiter, six years in the making, involved stripping back the building to the steel frame, removing asbestos, changing the roof and adding flood protection, as well as reorganising some of the three production lines where 480 employees together produce 5,500 turbines per week (280,000 per year). This factory specialises in small-batch production, and globally is supplemented by production in Columbus, Indiana, USA, Wuxi, Jiangsu, China and Pune, Maharashtra, India.
In addition to production and aftermarket operations, Huddersfield – which grew out of Holset, founded 71 years ago in the city – is also Cummins’s turbocharger technical centre, hosting 200 engineers and 100 technicians in testing, prototyping and metrology laboratories. Test facilities include 17 gas stands – which simulate exhaust gases with compressed air – alongside six test cells where turbochargers are mounted on actual engines, which provide a greater range of operation. All bristle with thermocouples and pressure transducers. Last year it redeveloped a test stand to provide for the e-turbo, adding an HV DC generator, as well as safety interlocks, and is currently building a 180-channel TC235 turbine performance test cell. These developments are essential to better understand the new products in development.
In January, the company reorganised its turbochargers, fuel systems and valvetrain technologies business – its 2022 acquisition of Jacobs Vehicle Systems – into a new engine components group, which united in the goal of helping customers run internal combustion engines as efficiently as possible.
The wider business also includes its Accelera by Cummins electrolyser and fuel cell business, which launched in March. That developed from the company’s acquisition of Hydrogenics in 2019.