recodrive Logo sugre project - Sugre Sustainable Green Fleets
top
 
Language:
search on site
sustainable europe

Supported by:

IEE logo
Update me about new download/training materials rss
back
Fuel logistics/refuelling Fuel properties of alternative fuels Alternative propulsion explained Driveability Incentives and laws Leasing and financing Operation and Maintenance Emission reduction potential

Technological potential
top

Introduction


This section provides speculative information which goes beyond the current technology on the market. But since shift to another fuel technology affects requirements for staff and depots which are an long term asset, we will outline potential long term developments. The most important questions are?
  • is there a potential to further improve the efficiency of the combination of fuel and engine?
  • is it possible/costly to meet future emission standards with this fuel?
  • may the technological path be upgraded to other fuels

This section is under construction!

Ethanol


Higher compression ratios are possible, direct injection is preferred because of cold start problems. Direct injection increases the cylinder loading which is necessary because of the small energy content of the fuel. Fuel evaporation cools down the air, the amount of fuel is 63% higher with the same amount of air. Lean burn concepts are preferred since more injected fuel would cause problems (longer injection period or fuel accumulation at the wall ) but Ethanol evaporates quickly. But efficient lean burn concepts will have more problems meeting the NOx-limits. Flexi fuel engines can be combined with hybrid technology, which will increase the energy efficiency (Saab has shown demonstration cars, Saab Aero).
Ethanol is a new fuel which may be blended into gasoline/petrol but is a different type of fuel than Fischer Tropsch FT-diesel. Flexible fuel vehicles might also run on lighter FT-fractions.
E-Diesel consists of Ethanol blended with lubricants and is used in compression ignition engines.

Fischer Tropsch FT/synthetic diesel


A cleaner operation allows wider operation range into higher engine loads. Thus also exhaust after treatment is easier. FT-fuels allow to choose the feedstock. On the other hand the fuel design will require adapting engines.

SVO/PPO


SVO is recommended only for swirl or pre chamber engines or two stroke low rpm ship diesel since the combustion starts slowly (with accelerated second phase) , the lower heating value is compensated partly by a lower air demand, special injection equipment is needed to avoid damages to it. The exhaust after treatment is comparable to fossil diesel. The fuel is very heterogeneous and requires totally different engines. Not highly sophisticated and efficient engines are needed but robust and slowly running. May be the trend to hybrid electric vehicles will introduce a new type of internal combustion engine which is more suited. This phlegmatisation (Atkinson/Miller cycle) is currently used only for spark ignition engines but also low rpm compression ignition engines might by developed in theory.

FAME/Biodiesel


FAME has a lower influence on engines compared to raw fuels like PPO/SVO, but injection pumps and articulated valves shall have external lubrification.
Exhaust cleaning is possible and even a little easier compared to fossil diesel. The engines are more robust to fuel deviations but in principle the assessment its similar to fossil diesel.

Methane


With methane higher compression ratios are possible, higher part load efficiency without throttle, efficiencies are approaching compression ignition engines. Use of glow plug and direct gas injection will increase the efficiency possibly hydrogen blending will further reduce CO2 emissions. The path to wood gas or pyrolysis gas is possible but require engine adaptations. May be sophisticated multi valve direct injection is as way to construct flexible gaseous fuel engines.

Hydrogen for ICE


With much higher compression ratios are possible. There is higher part load efficiency without throttle (direct injection). Hydrogen may be used in adapted natural gas engines. Exhaust cleaning is easier because of the low emissions.

Fuel cells


FC are under development and the hydrogen fuelled types are not necessarily the final solution for all of Europe although they have a very high tank to wheel efficiency and local zero emissions. Investments thus have to take into consideration the possibility to produce hydrogen from renewable sources. FC will not run on methanol, ethanol or even diesel, special developments are needed.
Criteria to be considered are:
  • kW/s dynamic
  • time to start from cold
  • technical service life
  • operational temperature/humidity range
  • total efficiency incl. auxiliaries over load
  • price €/kW
  • weight kg/kW
  • crossectional area required for cooler m²

Hybrid power trains


The internal combustion engines are released from high dynamic power requirements and low power operation - boost capability of electric motors is taking over. Energy storage or start stop operation avoids inefficient low power operation. Thus also spark ignition internal combustion engines may be used. Most important is downscaling of the engine which allows an operation in the higher efficiency areas. The phlegmatisation of the ICE eases the use of alternative fuels and cuts fuel enrichment caused emissions. Hybrid power trains are seen as a way to rethink the energy management for vehicles - reintroducing electric energy storage. But the potential is not usable for long distance travel at full power (trucks). With passenger vehicles a combination of powerful ICE engines and light electric equipment may allow to build versatile hybrid electric vehicles which have a lower highway fuel consumption. This will be caused by electric driven ancillaries (steering, cooling and braking).
The concept will also enter into the two wheel business (hyperbike.cc) soon.



  


  © FGM-AMOR 2005          login Prefer fuel saving? www.recodrive.eu Legal Disclaimer