Pathways to the Ultra- Efficient Powertrain – Towards 60% Efficiency

Pathways to the ultra- efficient powertrain – towards 60% efficiency

Future Powertrain 2017

Dr Robert Morgan Deputy Head, AEC University of Brighton Advanced Engineering Centre 2 University of Brighton

Improving thermal efficiency through fundamental understanding of the in cylinder processes

Confidential Copyright University of Brighton 2016 Are we at to the end of the road? 3

Wartsila RT-flex58T

Mechanical losses 3% Finite combustion 3% Mercedes F1 Blowby 1% Cycle to Cycle variations 2% Gas exchange 2% Heat transfer 7% TOTAL 18%

Stone 2012 Confidential Copyright University of Brighton 2016 4 Changing the rules – the split cycle engine, a new thermodynamic cycle

Independent 1. Isothermal compression Less work of compression optimisation of the 2. Isobaric heating Pre combustion waste compression & heat recovery expansion cylinders 3. Mixed cycle heat addition 4. Expansion

Confidential Copyright University of Brighton 2016 5 Why hasn't it been done before?

1909 Ricardo “Dolphin” engine 1 2004 “ISOENGINE” 2

¢Several engines with split compressor and combustion cylinders have been proposed

¢Only the Isoengine recovered heat between the chambers Scuderi Engine 3

1 Engines and Enterprise: The Life and Work of Sir Harry Ricardo 2 nd Ed 2Isoengine data analysis and future design options. Coney et al. CIMAC Congress 2004, Paper 83, Koyoto 3http://www.scuderigroup.com/engine-development/ Confidential Copyright University of Brighton 2016 There are multiple challenges in practically 6 implementing the recuperated split cycle engine

¢Effective isothermal compression √ Isoengine, Cool R

Cryopower ULTRA ¢High pressure recuperation, practical for mass manufacture

¢Practical valve system with a very short induction period at high T & P

¢Achieving complete and rapid combustion in the expansion stroke

Confidential Copyright University of Brighton 2016 Ideal pressure trace – minimal compression work, inlet / 7 chamber pressure equalised, rapid burn

Inlet valve lift Exhaust valve lift ~30° period

Inlet pressure

Pressure rise caused by air Cylinder Cylinder pressure induction, not compression! Rapid burn, 12-20°ATDC

TDC Crank angle

Confidential Copyright University of Brighton 2016 8 Engine system installation at Brighton

Gas storage bottles

Gas burner tube at c. 900° C

¢High pressure air system, delivers air up to 70 bar

¢Gas burner delivers heated air at 800°C

¢Prototype recuperator from Hiflux Engine installation ¢Split lubrication and cooling system Confidential Copyright University of Brighton 2016 800rpm, 47.9Nm, 900bar rail, 23:1 AFR, 25bar inlet 9 Start of Combustion phased to IVC

Inlet air works against piston Chamber filled prior to ignition

Confidential Copyright University of Brighton 2016 14 degrees of retard achieved, increasing torque to 10 91Nm

8.5bar/deg 30% increase In volume

Less works against piston, Some work recovery ATDC Inlet valve restricting flow and so the chamber is not fully filled

Confidential Copyright University of Brighton 2016 1200 rpm, 800bar rail, 23.9:1 AFR, 30bar, 688degC inlet 11 Combustion still stable with 6 degrees retard

Confidential Copyright University of Brighton 2016 Impact on cycle efficiency 12

-5

-10

-15

-20Changein thermalefficiency, % -30 -20 -10 0 10 20 30 Change in combustion period, degrees crank

Confidential Copyright University of Brighton 2016 13 How does the split cycle engine compare? (update from FPT2016)

Waste Advanced Chemical Split cycle heat combustion looping 43% BTE Current recovery (two fuels) +WHR best in class heavy Baseline duty diesel WHR Advanced Isothermal 45% BTE combustion Reduce H 2 slip compression

Improved Advanced optimisation 47% BTE Recuperation WHR combustion

50% BTE 48% BTE 50% BTE

Optimisation of CR/ER & insulation 55% BTE

Normal Fast burning fuel fuels 58% BTE 60% BTE

Closed hybrid cycles?

¢Are we approaching the limits of what can be achieved with a conventional Otto or Diesel cycle?

¢But the reciprocating engine still offers many advantages over other solutions in particular in high power – long range applications

¢New approaches are needed to achieve a clean propulsion system that breaks the 50% efficiency barrier

¢The split cycle engine offers a solution, with the potential to approach 60% BTE

¢Testing has proved the viability of the combustion system – the main outstanding challenge!