OK hydrogen by itself can be compressed and stored. How are you planning to separate it? A home built splitter reactor will not split it clean enough!! Next how are you going to fill a cylinder compressed to 2000 lbs? If you do not compress it you will only have enough hydrogen to start the engine and that will be about all. The proper equipment to achieve what you are going to try to do is going to make the project not worth it in my book anyway. You will then have a problem with imbrittlement of the engine if you did get clean hydrogen made and compressed. This will destroy a normal engine. Bottom line it is going to cost an arm and a leg to solve just these few problems and there is more, making it so expensive that unless you have a bundle of money you just want to throw away for the fun of it, you should come up with some other idea. Maybe I need new glasses but that is how I see it.