This .blend contains a material group that lets you preview how your models will look in Unreal Engine 4 following the default lighting model.

Just delete the demo monkeys, save the .blend as something else, and you've got a handy library .blend that you can append to any file to get the node group that has the lighting model in it.

I'm pretty sure this is quite close to the UE4 lighting model. It may not be a dead ringer, though, so if you see an important difference or discrepancy don't hesitate to let me know! I think I probably did Fresnel wrong, so if someone who knows something could check that, that would be great.