With road transport accounting for approximately 10% of all global emissions, global shipping producing approximately 3% of global CO2 emissions & aviation approximately 12% of global emissions: the need to move to zero emissions & net zero is of paramount importance.
The transition to zero emission road vehicles is not a new concept, but rather than the technology being designed for an elite customer base with costs for EV’s in particular being out of the financial scope of many average working families; the plans for zero emissions vehicles going forward are to make them more accessible to a much wider audience.
With many global cities having already become car free, ULEZ’s appearing in most major cities in the UK & many other global cities already planning to remove cars entirely; the investment in zero emissions public transport is also being ramped up.
Electric trams have been in operation for decades, but now we are seeing the investment into removing diesel buses & replacing with electric or hydrogen & the Taxi’s in London are slowly being replaced by electric.
Despite the pledges made at last year’s COP26, not all were in agreement of the focus being very much on the transition to electric passenger cars for example. The Sustainable Transport Alliance pointed out that ever more cars, however they’re powered, will mean more congestion & more impact on the roads that the vehicles are driven on. (1)
All EV’s require a lot of energy & materials in their construction & delivery to their end users, making it questionable if an EV can be an entirely net zero product. Various life cycle analysis data sets still point towards traditional ICE or even diesel models having the least environmental impact over the lifetime that the vehicle is in use.(1)
The various stages in the life cycle include vehicle manufacturing, operation, & vehicle after-life
management. Vehicle production involves the material procurement & processing phase.
The operational cycle includes fuel production (petroleum or electricity based on the vehicle) &
utilization of the fuel in the vehicle. Vehicle afterlife management includes vehicle and powertrain
disposal, material substitution through any remanufacturing, & recycling. (5)
The Sustainable Transport Alliance want to see countries shift away from electrifying cars & instead reduce their number altogether, making other forms of transport more attractive & less congested. (1)
The UK Government announced as part of it’s 10 point Green Industrial Revolution in November 2020 that from 2030 the UK will end the sale of new petrol & diesel cars & vans, 10 years earlier than planned. This poses the question, what plans do the UK Government have to extend this reach to heavy duty?
It is no secret that although it has been relatively easy to electrify or hybridise passenger vehicles such as cars, small vans & public transport, including some trains; the heavy duty, off-highway, construction, marine & aviation sectors are still finding it a challenge to get to zero emissions.
With these sectors relying on hundreds of tonnes of machinery being able to either drive on roads, construction sites, at sea or in the air with established engine & fuel methods proving they have the power & longevity to maintain their capacity; how can these sectors find ways to reach the targets set under the Paris Agreement, by International Governments & uphold the pledges made at the 2021 COP26?
Despite the inherent challenges posed by the heavy duty sector, the UK Government confirmed on in November 2021 that all new heavy goods vehicles in the UK will be zero-emissions by 2040.
The UK will become the first country in the world to commit to phasing out new, non-zero emission heavy goods vehicles weighing 26 tonnes & under by 2035, with all new HGVs sold in the UK to be zero emission by 2040. (2)
This is a very ambitious target, with technology particularly in the heavy duty sector needing some considerable investment & development to still remain a viable competitor to the longevity of the traditional diesel engine.
Despite huge developments in electrification for heavy duty vehicles, the Automotive Council roadmaps for 2020 identify that different vehicle applications will still require different powertrain solutions based on their energy & power demands. (3)
Even though there have been considerable developments in battery electric off-highway vehicles in Europe & the roll out of highways with inbuilt pantograph power collectors to charge on board batteries; this is still very much in the development phase.
One such development is the Dolphin N2 Recuperated Split Cycle Engine. The Recuperated Split Cycle is an internal combustion engine, with all that implies in terms of low cost & ease of manufacture, that aims to compete with zero emission drivetrains. (4)
Dolphin N2 have had a multi-cylinder prototype of the running engine since December 2020 & the data already looks promising with high thermal efficiency –55-60% BTE, low emissions – NOx at SULEV or below with standard SCR & fuel compatibility with Diesel, Methane & Hydrogen
The Dolphin N2 technology specifically targets heavy duty & the long-haul sectors where most commercial vehicle CO2 originates & alternatives are the most challenging.
The Basic Cycle of the Recuperated Spilt Cycle Engine is made up of: Dedicated Cold & Hot cylinders of unequal size, Insulation of hot cylinder, Recuperation of exhaust energy, Low-NOx Cool Combustion enabled by dense sonic intake air & Cooled Compression.
Although the Dolphin N2 engine & the technology built around it uses the efficiency of a diesel engine as it’s base model, the developments mean that the RSCE can also be run on methane & hydrogen.
Hydrogen is politically favoured as an “alternative to electricity” for an on-highway application as it is already readily produced from renewables, with zero “source to tank” & net GHG (which matters) Hydrogen also produces zero GHG at the tailpipe (politically popular), is fairly quick to refuel – the energy density is acceptable with compromise & it suits both Fuel Cell & ICE – creating critical mass of demand.
The benefits of a Hydrogen ICE are that a Hydrogen ICE works, is fast to adopt, uses the same supply chain as current manufacturers, has familiar servicing needs, NOx is entirely manageable via lean burn & in principle it suits a Recuperated Split Cycle. “Fast oxidation” combustion is fuel agnostic – violent mixing with red-hot sonic & supercritical air will burn many things & if Hydrogen can maintain BOTH high efficiency & low NOx, the advantages are clear. (6)
Written & cited by Katy Mason for & on behalf of Dolphin N2