Present & Future Models for Automotive Prime Movers P M V Subbarao Professor Mechanical Engineering Department Better Structure of an Artificial Horse to Mimic a Horse…

The Reference Target: may Engine must be many times a Horse

Anatomy of an Artificial Horse for Busy Roads ???

The Biological Measure of Intelligence Species Simple brain-to body ratio (E:S)[1] small ants 1:7[2] tree shrew 1:10 small birds 1:14 human 1:40 mouse cat 1:110 dog 1:125 squirrel 1:150 frog 1:172 lion 1:550 elephant 1:560 horse 1:600 shark 1:2496 hippopotamus 1:2789

Evolution of Intelligent Species : Natural Engine

Future Trends : Road fuel use and CO2 by vehicle type

The Great Power Train Race

The Type of Prime Mover for Light Vehicle Sales in Two Decades

Why I.C. Engines in 21st Century? Electric vehicles (EVs) Batteries are heavy ≈ 120/kg of gasoline equivalent Fuel cells better, but still nowhere near gasoline "Zero emissions" myth - EVs export pollution Environmental cost of battery materials

The Concept of Green Car In any case, all-electric cars are green only if the electricity to recharge them is generated in low-carbon ways. In nuclear-powered France the electricity to drive a battery car one kilometre causes carbon-dioxide emissions of just 8g. Yet in China and India, which generate much of their electricity from coal, those emissions are over 120g. It would be greener to drive a new petrol/Diesel-engined car instead. Solar Car

The Scope for Innovation All sorts of industries are pumping money into making batteries more efficient and cheaper, but there are no breakthroughs round the corner Conventionally fuelled cars have been getting more efficient for decades. A study by Michael Sivak of the University of Michigan found that between 1970 and 2010 the average fuel economy of America’s car fleet improved by 66%. Now money is being poured into making it even better A recent survey found that in big emerging markets especially, the motor industry was switching its research funds back to the internal-combustion engine.

Future of Car Engines Car engines are continuing to shrink, but are now being fitted with things like turbochargers and fuel-injection systems that used to be available only on more expensive models. This means they cost more to make but achieve better mileage without loss of performance. Other fuel-saving gadgets include “start-stop”, in which the engine cuts out during idling, and various means of storing the energy released by braking.

The Art of Down Sizing an Engine

Future Targets for Fuel Economy of LCVs

Space for innovation in Conventional Concepts - factor of 2 in efficiency Ideal Otto cycle engine with CR = 8: 52% Real engine: 25 - 30% Differences because of Throttling losses Heat losses Friction losses

Space for innovation - infinite in pollutants Pollutants are a non-equilibrium effect Burn: Fuel + O2 + N2  H2O + CO2 + N2 + CO + UHC + NO On A Faster Expansion: CO + UHC + NO “frozen” at high level With slow expansion, no heat loss: CO + UHC + NO H2O + CO2 + N2 But how to slow the expansion and eliminate heat loss? Worst problems: cold start, transients, old or out-of-tune vehicles . 90% of pollution generated by 10% of vehicles !!!!

Space for innovation - very little in power IC engines are air processors Fuel takes up little space Power  Air flow Limitation on air flow due to “Choked” flow past intake valves Frictional losses, mechanical strength - limits RPM Slow burn Majority of power is used to overcome air resistance - smaller, more aerodynamic vehicles beneficial

Clues for Improvement- alternative fuels : Natural Gas Somewhat cleaner than gasoline, non-toxic High octane without refining or additives (≈ 110) No cold start problem Half the CO2 emission of EVs charged with coal-generated electricity Dual-fuel (gasoline + natural gas) easily accommodated Lower energy storage density (≈ 1/4 gasoline) Lower power (≈ 7% less) Attractive for fleet vehicles with limited territory Renewable bio-methane could increasingly take the place of fossil-fuel gas. The IC Engine is not addicted to fossil fuels …. WE ARE!

Clues for Improvement - alternative fuels – Alcohols/Bio-Diesels Slightly cleaner than gasoline High octane (≈ 95)/ varying (48 – 67) Cetane Not cost-effective without price subsidy Lower storage density (methanol ≈ 1/2 gasoline) Toxic combustion products (aldehydes) Attractive to farm states

Clues for Improvement- alternative fuels - Hydrogen Ultimate clean fuel Excellent combustion properties Ideal for fuel cells Very low storage density (1/10 gasoline) Need to manufacture - usually from electricity + H2O Attractive when we have unlimited cheap clean source of electricity and breakthrough in hydrogen storage technology

Clues for Improvement- reduce heat loss Heat losses caused by high engine turbulence level Need high turbulence to Wrinkle flame (premixed charge, gasoline) Disperse fuel droplets (nonpremixed charge, Diesel) "Inverse-engineer" engine for low-turbulenc Gasoline - electrically-induced flame wrinkling? Diesel - electrostatic dispersion of fuel in chamber?

Clues for Improvement - reduce throttling loss Premixed-charge IC engines frequently operated at lower than maximum torque output (throttled conditions) Throttling adjusts torque output of engines by reducing intake density through decrease in pressure ( P = rRT) Throttling losses substantial at part load

Clues for Improvement for improvements : Reduce Friction Losses Programmable intake/exhaust valve timing Electrical/hydraulic valve actuation Choose open/close timing to optimize power, emissions, efficiency - can eliminate throttling loss

Clues for Improvement for improvements : Down Sizing

Clues for Improvement : Reduce NOx Homogeneous ignition engine - controlled knocking Burn much leaner mixtures - higher efficiency, lower Nox Need to abandon traditional combustion control strategy

Ideas - improved lean-limit operation Recent experiments & modelling suggest lean-limit rough operation is a chaotic process Feedback via exhaust gas residual Could optimize spark timing on a cycle-to-cycle basis Need to infer state of gas & predict burn time for next cycle - need in-cylinder sensors

Conclusions IC engines are the non-ideal form of horse. Despite over 100 years of evolution, IC engines are far from optimized Any new idea must consider many factors, e.g. Where significant gains can & cannot be made Cost Resistance of suppliers & consumers to change Easiest near-term change: natural-gas vehicles for fleet & commuters Longer-term solutions mostly require improved (cheaper) Sensors (especially in-cylinder temperature, pressure) Actuators (especially intake valves)