Intelligence is about capability. Knowledge is about education.
Obviously there is some cross over with some displayed knowledge.
That seems like a sensible distinction on the whole.
Maybe another way of approaching 'smartness' or 'intelligence' is the value that a person's level of those things has, within a certain set of circumstances.
For example, take your classic apocalyptic zombie scenario. You are trapped in your garage and your car won't start, and to make things worse you have no prior mechanical experience, but you really need to get it started.
In my opinion, a very smart person will be able to start that car eventually (so long as no new parts are needed/specialist machinery etc etc). The reason being, that it is just within them to work it out.
On the contrary, you may have a 50 year old car mechanic in the same situation who is as dumb as a sack of rocks. Yes, he will start the car in no time, but only because of learned behaviour and skills he's aquired.