locomotive

When tractors were first developed, they used enormous steam engines which were notoriously unreliable and challenging to maintain. These were phased out round the turn in the 20th century and substituted with internal combustion engines that have been more compact yet still powerful and ran on the variety of fuels including kerosene, ethanol and gasoline. By the 1960s many of these engines were phased out and only more effective internal combustion engines that ran on diesel and after this, biodiesel. The EGR system routes a number of the exhaust gases (6 ? 10%) over the EGR valve, in for the Intake System, and finally inside combustion chamber. The exhaust gases are inert i.e. they cannot burn within the combustion chamber; also, the exhaust gases take up many of the space which will rather be taken from the intake air. This reduces the level of intake air available for the combustion process during each Power Stroke; which experts claim decreases the peak combustion temperatures. This leads to lower NOx emissions.