MIT has done some research on adding hydrogen to the fuel mixture within an engine in order to improve emissions. The hydrogen is made by using an electric arc to pyrolyze a little of the hydrocarbon fuel. I performed some arc-pyrolysis experiments, but I was using more power in electricity that what could be obtained from the hydrogen that was produced. However, there are other arc/plasma devices out there that could do the pyrolysis much more efficiently, such as GlidArc, Kaevner, and Huels. Look-up my papers and dissertation at
Publications for more information. If you want to tackle the topic of on-board pyrolysis as a way of implementing a hydrogen-fueled vehicle - stick to paper research (experiments will set you way too far back in time and expense). See what devices are out there and how much energy they consume to produce hydrogen. The hydrogen could be burned in an engine or go to a fuel cell.
If you are really keen on doing an experiment with a car, I would recommend surveying the temperature distribution in the engine compartment and/or the vehicle underside. You could order some temperature indicators from omega.com (lacquer, crayons, adhesive dots or strips) apply them to your car and then take photos to see what temperatures were exceed where. Heat tends to kill the electronics that are under the hood and I have heard anecdotes about gas tanks getting excessively hot. Look-up SAE paper 910307 Williams, Oler, Hackett, Hammar "Water Flow Simulation of Automotive Underhood airflow Phenomena" for some background research. There are probably more good papers since '91 that I am not aware of.
Finally, try to check MIT out to see if it is really the right environment for you. I don't know about MIT, but some departments with big reputations really don't give a crap about undergrads (or perhaps even grad students). As long as they got people clamoring to get in, they would just as soon flunk you as look at you.