Main objective of “Integrated gas powertrain (InGas)” Collaborative Project is to deploy a custom designed engine integrated with specific aftertreatment systems applied to a light duty vehicle able to achieve a 10% higher fuel conversion efficiency than that of a corresponding 2006 diesel vehicle and complying with an emission level lower than Euro 6. Additional features are advanced storage systems and vehicle architectures, as well as multi-grade fuel tolerance and fuel flexibility. To achieve the InGas targets, three main combustion technologies will be compared: Sub-Project A1 “CNG technologies for passenger cars” will develop a natural gas car powered by a 1.4 liter displacement engine using the sequential multi-point port gas injection and following the stoichiometric approach; Sub-Project A2 “Turbo DI CNG engine” will develop a natural gas car powered by a 1.8 liter displacement engine using the direct gas in-cylinder injection and following a lean burn approach; Sub-Project A3 “Boosted lean burn gas engine” will develop a natural gas light-duty vehicle powered by a 1.9 liter displacement engine using port gas injection or low pressure direct gas injection and following the ultra-lean combustion approach. Three main enabling technologies will be compared and assessed Sub-Project B0 “Fuels for advanced CNG engines” will define / supply the gas mixture of the requested quality, conduct analysis and propose solutions in order to affect in a flexible way storage, combustion, aftertreatment and performance of the CNG vehicles; Sub-Project B1 “Gas storage for passenger car CNG engine” will develop advanced gas storage and filling systems including specific components and gas sensors; Sub-Project B2 “Aftertreatment for passenger car CNG engine” will develop an aftertreatment system for natural gas vehicles having special regards to CH4 conversion efficiency and NOx abatement under stoichiometric and lean combustion operations.