In a pattern inspecting apparatus, images of places which can be expected to be the same pattern are compared with one another. The drive train also includes a slave sprocket fixed to the flywheel at the hub, with the drive and slave sprockets connected in a direct-drive relationship, the drive train driveable in a forward and rearward directions to cause the flywheel to rotate. The engine further includes a variable geometry EGR turbine located on the EGR line, driven by the EGR gas flowing in the EGR line.