4D: Alternative fuels – energy use and emissions

This project will identify the most promising opportunities for partial or full fuel substitution in compression ignition engines, with a view to GHG reduction, while complying with the relevant noxious emissions standards.


(i)  Determine and compile emissions factors for alternative fuel technologies accounting for direct and lifecycle energy use and emissions.
(ii) Evaluate the impact of dual fuel (diesel and natural gas) vehicles on noxious and greenhouse gas (GHG) emissions; and implement the findings into a tool used to determine vehicle emissions in conjunction with task 4A.
(iii) Test modifications optimized for the use alternative fuels on dedicated laboratory engines.
(iv) Compile a database of fuel consumption and emissions maps for heavy goods vehicles by chassis dynamometer and in-use measurement methods.

Programme, Methodology and Deliverables

Project Tasks

  • Task 4D1: Emissions factors for alternative (diesel replacement) fuels. This project will focus on quantifying the fuel carbon intensity of diesel fuel alternatives for HGVs in the UK context. The work will leverage existing LCA models which include probability distribution functions of alternative fuel carbon intensity relative to diesel fuels and will include factors from biomass production to in-cylinder combustion characteristics.
  • Task 4D2 Evaluation of tailpipe emissions in dual-fuel operations: This project will involve testing dual fuel (natural gas/diesel systems) vehicle emissions on chassis dynamometers and on test tracks, and then comparing the results to diesel vehicles. We will investigate emissions characteristics of such vehicles, based on a range of operating conditions / duty cycles and different injection settings / fuel ratios. Measurements will include noxious emissions and greenhouse gas emissions, including methane and particulate matter. The results of these tests will be used to develop RPM and load specific emissions inventories that can then be mapped to drive cycles. Combined with efforts in project 4A the local emissions of noxious pollutants will be incorporated into the vehicle emissions models and tested for a different logistical routes and driver behaviors.
  • Task 4D3: Laboratory investigation of after treatment technologies for alternative fuel vehicles: The aim is to minimize tail-pipe emissions of GHGs from biofuels, while maintaining PM and noxious emissions within regulatory limits. In order to limit the scope of testing, outcomes from task 4D2 will be used along with stakeholder input to determine the a matrix of conditions and technologies that are most promising to evaluate for optimization of technologies with alternative fuels. GHG benefits for the target fuel types will be investigated via experimentally-informed emulations of in-use driving conditions. Optimisation of automotive after treatment technologies, such as methane catalysts, will be carried out for a variety of engine parameters (fuel injection strategy), fuel type/mix (methane/diesel) control and exhaust temperatures. Impacts of the work will be to determine the effectiveness of after treatment in reducing unwanted emissions of GHGs (methane) and noxious pollutants (non-methane hydrocarbons).
  • Task 4D4: Database of energy use and emissions maps: This work will seek to develop strategies for determining energy use and emissions maps from in-service vehicles. Such techniques would allow for the testing of a variety of alternative fuel and drivetrain vehicles via cost effective methods. The resulting database will consist of outputs from in-service testing (in conjunction with Project 4A) that can be used for evaluation of technologies to meet cost and emissions standards.


The work will result in: (i) emissions factors for alternative fuels, (ii) experimental results examining the impact of dual fuel technologies on noxious and GHG emissions, (iii) assess the potential for alternative fuels by investigating necessary after treatment technologies and (iv) compile a database of energy use and emissions engine maps that will enable energy and emissions models.


  • Existing vehicle fuel consumption model Staffing for validation of fuel consumption
  • Delivery vehicles for validation in conjunction with industrial partners


  • Academic impact: The interaction between engine operating conditions/fuel and after-treatment is very complex, and careful experimental investigations are still essential in an area where modelling procedures are woefully inadequate. Further research in the optimization of vehicles with non- typical fuels will also be an important contribution.
  • Commercial and social impact: Carefully evaluated advantages and disadvantages of alternative fuel scenarios will be important in making the case for their more widespread introduction in the market. An important impact of this work is the development of a tool that allows the industry to determine the noxious emissions and fuel carbon intensity of alternative fuels.