INTRODUCTION

With the stock of fossil fuels diminishing throughout the world and demand for energy based comforts and mobility ever increasing, time is ripe that we strike a balance between energy security and energy usage. Moreover having uplifted to such a sphere of engineering excellence, reverting back to the ages of the bull carts will prove next to impossible thereby compelling us to search for a basket of alternative fuels to derive energy to cater to our needs. Several sources of energy, especially for driving the automotives are being developed and tested. Judicious utilization of this basket of energy is the call of the hour for a nation to see itself through the tough days ahead.

Today's engine development is heavily controlled by increasingly stringent emission legislation, leading to rapid developments. The EEV (Enhanced Environmentally Friendly Vehicles)-standards is coming into force for polluted cities, creating an extra incentive for the development of extra clean vehicle technology. The future of gaseous/alternative fuels depends on the maximum of polluting emission allowed, the technology available and the cost of concepts developed. Promising developments are taking place in the area of the conventional prime mover, the diesel engine.

At the end of the day the concept that fulfils all legislative requirements and can be sold at the lowest price will be the winner. And that may be an engine running on a conventional or on an alternative fuel or most likely on both.

The alternatives to petroleum-based fuels must meet the following criteria, if they are going to be used widely for transportation.

- Technical acceptability

- Economically competitive

- Environmentally acceptable

- Safety & availability.

Based on the above criteria, several alternate fuels have been considered from time to time all over the world as low cost substitutes for gasoline and diesel. Lately they have gained importance as clean fuels. The prominent among these are, boidiesel, electric fuel, ethanol, hydrogen, methanol, natural gas (CNG/LNG), propane (LPG), DME, P-series and solar fuels.