Background

Climate change and shortage of crude oil are real threats. Due to these threats, use of fossil fuels has to be reduced to a fraction of the volumes today. To achieve that level of reduction in road transport, vehicles have to be much more efficient and renewable energy must be commercialized.

Due to EU efficiency legislation on light duty vehicles (LDV), ordinary cars are now rapidly getting more fuel efficient. Small and middle class cars will be equipped with direct injected gasoline engines and bigger cars will be driven by rather small turbocharged diesel engines. Some manufacturers are launching plug-in hybrids which can have their batteries charged from the grid. This ongoing development will result in less need for gasoline and a growing demand for diesel oil, especially for heavy duty vehicles. (HDV). Jet fuels depend on same components as diesel and furthermore heavy oils in marine applications will probably be substituted by lighter fractions. The existing imbalance today between petrol and diesel in refineries will increase. Substitutes for fossil diesel oil are crucial. Shortage of diesel oil is perhaps the biggest near-term threat when it comes to energy supply for road transportation.

Two optional routes offer viable solutions. One route is to substitute crude oil based diesel oil with a synthetic fuel as F-T diesel or HVO (Hydro treated vegetable oils). Another route is to modify the heavy, still compression ignited, engine to enable use of other fuels. Bio methane can be such a fuel. Methane is a globally used fuel which is a prerequisite for manufacturers to develop high efficient methane engines.

The most interesting use of bio methane is in HDV´s. The volumes are predictable and even higher than for LDV´s. The infrastructure will be relative simple and cheap. More important is, in HDV´s Bio methane always substitute diesel oil. Liquefied methane can be a cost effective solution in long haul transportation. Methane in HD engines is a very interesting issue.

Purpose and Objectives

The recommended road map for future work, phase two of the project, is highlighted as follows:

• Continue the dialog with suppliers of DDF-concepts and interested OEM´s
• Verify present status of fuel efficiency and emission performance for commercial available DDF concepts
• Benchmarking of available concepts (DDF & SI) for methane fuelled HD engines
• Develop a first proposal of a certification scheme for HD dual fuel engines
• Consider methods for verification of emission performance for methane fuelled HD engines in normal operation (I & M program)

Activities

Based on experience from limited initial testing of DDF concepts AVL MTC propose that the following test program should be carried out:

1. Start of warm engine, test cell temperature 20 – 30°C. Stationary testing using international accepted test cycle (preferably WHSC) with measurement of at least CO, THC, CH4, NOx and PMmass, if possible also particle number and size distribution. In some of the selected measuring points also diesel replacement should be measured. Calculation of emissions in g/kWh in accordance with recognised protocol.
2. Transient testing using international accepted test cycle (preferably WHTC, warm start) with measurement of at least CO, THC, CH4, NOx and PMmass. Test sequence should be carried out in duplicate (2 tests). Calculation of emissions in g/kWh in accordance with recognised protocol.
3. Additional measurement of NO2, N2O and NH3 should be carried out to get the full picture of emitted GHG emissions.
4. Measurement of λ (lambda) and exhaust temperature before DOC for possible identification where improper operation of the complete system could occur.
5. Testing of the vehicle during one day under various operating conditions in order to verify real word emissions. Driving pattern/schedule TBD.

Test program should be designed to make it possible to calculate energy efficiency, diesel replacement and consumption of energy (diesel and/or gas).The result from testing should show the potential for the different concepts.

To cover present commercial available concepts considered to be state-of-the-art the test program should preferably consist of following technologies:

• Diesel duel fuel concept – Hardstaff OIGI
• Diesel dual fuel concept – Clean Air Power
• Diesel dual fuel concept – Cummins Westport HPDI
• Diesel dual fuel concept – Bosch
• Dedicated gas concept – Stoichiometric combustion (various OEM)
• Dedicated gas concept – Lean Burn combustions (limited OEM)

The vehicles tested should preferably meeting emission standards according to Euro V/VI or corresponding requirements in USA and Japan.