Emission regulations of the mobile machines have created lot of work for the machine manufacturers in recent years because of the Stage 4 /Tier 4 final regulations. The work will continue because the new EU stage 5 emission regulations for non-road-mobile-machines was published at the year 2016. Emission reduction is realized by different emission reduction systems that are located in the exhaust system in combination with sophisticated combustion control. The after treatment systems increase complexity and size of the exhaust system. Increased creation of NOx and particle emissions are related to sudden load and speed changes of the engine. This paper introduces effect of driving style on the real emissions of the municipal tractor and solutions to decrease emissions with hydraulic hybrid. Measurements show that the sudden load changes increase raw NOx and particle emissions (non after-treated emissions) and operators driving style has effect on the emissions. Stabilizing the load of the engine by the hybrid system reduces NOx and particle generation. When the engine load variation is minimized the size of the exhaust after treatment systems can be reduced.
Keywords: Non-road mobile machine, exhaust emissions, hydraulic hybrid