Exhaust emission reduction and improvements in energy consumption will continuously determine future developments of on-road and off-road engines. Fuel flexibility by substituting Diesel with Natural Gas is becoming increasingly important. To meet these future requirements engines will get more complex. Additional and more advanced accessory systems for waste heat recovery (WHR), gaseous fuel supply, exhaust after-treatment and controls will be added to the base engine. This additional complexity will increase package size, weight and cost of the complete powertrain. Another critical element in future engine development is the optimization of the base engine. Fundamental questions are how much the base engine can contribute to meet the future exhaust emission standards, including CO2 and how much of the incremental size, weight and cost of the additional accessories can be compensated by optimizing the base engine.This paper describes options and potentials to improve the base engine for future commercial and industrial engines. Downsizing engine displacement, new materials, friction reduction and advanced boosting and fuel injection technologies have demonstrated potentials in light-duty vehicles and implementation is underway. The paper will provide an outlook of how these technologies can improve the base engine for commercial and industrial applications with regards to future exhaust emission and fuel efficiency requirements.