Kon-0.1100 - General information in Machine technology: Group 8

Environmental Aspects of Various Traffic Powertrain Options

Special focus on Hybrids & EVs

Types of Powertrain

NB: All stated efficiencies are “Tank to Wheel”, NOT “Well to wheel”. For EVs, implies “plug to wheel”, not “power plant to wheel”

Fuel, technology or energy carrier

Comments Energy carrier or primary fuel

Suitability for different applications

Petrol SI engine. 95E 10% ethanol in FI. Circa 30-35% efficiency.

Fuel Passenger cars

Bioethanol SI engine. +20-50% fuel consumption compared to equiv petrol engine. Can be mixed in petrol. Circa 25-35% efficiency.Food vs fuel issue.

Fuel Passenger cars

Diesel CI engine. Circa 40-45% efficiency. Fuel Passenger cars, buses, trucks

Biodiesel CI engine. Performs same as diesel. Can be mixed in diesel. Circa 40-45% efficiency.Food vs fuel

Fuel Passenger cars, buses, trucks

Natural gas SI engine or dual fuel CI engine (pilot start on diesel). Tank is quite space consuming. Circa 30-35% efficiency (SI), 40-45% (CI)

Fuel Passenger cars (generally SI), buses, trucks (SI or CI)

Types of Powertrain (2)Fuel, technology or energy carrier

Comments Energy carrier or primary fuel

Suitability for different applications

Hydrogen Fuel cell efficiency, 50-60% OR SI engine (same efficiency as petrol, BMW was interested),. Tank larger than petrol or diesel.

Energy carrier

Passenger cars, buses, truck possible but tank and fuel cell size is limiting factor but possible

Hybrids, Plug-in hybrids

Hybrid is petrol or diesel only but recover braking energy and e.g. uses electric motor in partial load conditions. Circa 50% total efficiency. Plug in hybrid also has chargeable battery and has significant electric only range.

Petrol or diesel fuel (with main electricity for PHEV, i.e. energy carrier)

Best in urban (lot of braking, idling) and variable load condition. Passenger cars, buses, light duty trucks, HGVs may be possible but need large battery to recover useful braking energy and tend to run in constant load conditions.

Pure electric vehicle

Battery and electric motor only. Battery energy density limits range (max circa 200km practical for current EV car technology). Circa 70% total system efficiency (small loses in charging, electric)

Energy carrier

Passenger cars, city buses, light commercial vehicle used in urban areas.

NB: All stated efficiencies are “Tank to Wheel”, NOT “Well to wheel”. For EVs, implies “plug to wheel”, not “power plant to wheel”

Power train emission characteristics for passenger carsFuel, technology or energy carrier

CO (mg/km)Euro 5 limit

NOx

(mg/km)Euro 5 limit

PMEuro 5 limit

Average CO2 (g/km). EU Target:130 g/km at 2015,95 g/km at 2020

Comment

Petrol 1000 60 5 150

Bioethanol As per petrol Recycle of carbon dioxide, typical life cycle emission reduction of 50%+ over fossil petrol

Diesel 500 180 5 141 EU target (Euro 6 starts 2014):Reduce amount of nitrogen oxides, e.g. by selective cat reduction (SCR, urea(!) injection), already on trucks

Biodiesel 500 180 5 Recycle of carbon dioxidetypical life cycle emission reduction of 50%+ over fossil petrol

Natural gas 1000 60 5 129 (Opel Zafira Tourer), can be 80 for small car (Fiat Panda NG)

Hydrogen – Fuel Cell

NA NA NA Zero at vehicle. But lifecycle emission may vary from around 200 (hydrogen from natural gas reforming) to zero (hydrogen from electrolysis from RES-Electricity).

Emission: water and some nitrogen oxides (more if hydrogen internal combustion engine rather than fuel cell)

Hybrids, Plug-in hybrids (PHEV)

As per petrol, but actual emissions much lower than normal petrol

104 (Toyota Prius Gen II), 90 (Prius Gen III), 50 (Prius Gen III PHEV, not include CO2 from electricity input)

Pure electric vehicle

NA NA NA Zero at vehicle. Lifecycle emissions around 100 for EU-27 average power plant CO2 factor of 400g/kWh and EV consumption of 0.25kWh/km). Zero if using RES or Nuclear electricity.

No emissions in traffic, but while producing electricity.

EU’s targets

• EU’s target is to reduce emissions from 1990 levels by 20 % by 2020

• EU’s target (CO2 emissions) for– a new passenger car is

• 130 g/km at 2015• 95 g/km at 2020

– a new van is• 175 g/km at 2017• 147 g/km at 2020

• EU is aiming to increase the share of the renewable energy to 20% of the final energy consumption by 2020

• • Arska is hydrogen guy too

Oil is easy answer

Electric car

• Efficiency in electric cars is 85% (30-32%) when in petrol cars its 20-25%

• Energies that some batteries can hold:

– Lead battery 20-40 Wh/kg

– Lithium-ion battery 70-130 Wh/kg

– Petrol can hold about 12 000 Wh/kg

• Companies are developing new and better batteries so electric cars can run longer

• Today most used batteries are lithium and lead batteries

• To load batteries it takes many hours but new technology is developing that can charge electric cars lot faster

• Electric cars with lead batteries can travel up to 100 km

• With new lithium-ion batteries cars can travel 160 km

Hybrids

• Hybrid electric vehicles (HEVs) use petroleum engine and at least one electric motor

• Petroleum engine produces energy for propulsion, other technical solutions recycle the energy

• Batteries store extra energy and electric motor transforms it to thrust

• Generative breaking and constant engine drive recharge batteries

• Other green solutions as automatic engine stop and start when not moving are also common in HEVs

• On low velocities all HEV’s thrust is provided by the electric motor

• Parallel use of engine and motor reduces fuel consumption and emissions

KERS

• =Kinetic Energy Recycling System• Used in Formula 1 and other motor sports• Energy can be stored either as

– mechanical energy as in a flywheel– electrical energy as in a battery

• Extra 60 kW available for 6.67 seconds per lapBenefit per lap is approximately 0.1 to 0.4 seconds

• Has a bad reputation because of high price tag for small gain, inreliability and electric shocks