The DeLorean time machine is a fictional automobile-based time travel device featured in the Back to the Future trilogy. In the feature film series, Dr. Emmett “Doc” Brown builds a time machine from a DeLorean DMC-12 with the intent of gaining insights into history and the future but instead winds up using it to travel across 130 years of Hill Valley history (from 1885 to 2015) undoing the negative effects of time travel.
The operation of the DeLorean time machine was consistent throughout all three films. The operator sat inside the DeLorean, (except for the first time when a remote control was used), and turned on the time circuits, activating a unit containing multiple seven-segment displays which showed the destination, present, and last-departed dates and times. After entering a target date, the operator accelerated the car to 88 mi/h (142 km/h) which activated the flux capacitor. As it accelerates, several rails around the body of the car glow blue. Surrounded by large sparks, the whole car vanishes in a flash of blue light seconds later, leaving a pair of fire trails behind. Observers outside the vehicle see an implosion of plasma as the vehicle disappears, while occupants within the vehicle see a quick flash of light and instantaneously arrive at the target time in the same spatial location (relative to the Earth) as when it departed. Immediately preceding the car’s arrival, three large and loud flashes issue forth from the point from which the car emerges from its time travel. After the trip, the DeLorean is extremely cold, and frost forms from atmospheric moisture all over the car’s body. A few technical glitches with the DeLorean hindered time travel for its inhabitants; in the first movie the car had starter problems and had a hard time turning over once stopped, much to Marty’s repeated frustration. In the second movie the time display would act up and show random dates, which partially caused Doc to be sent to 1885. In the third movie the fuel line ripped and the car could not run under its own power (see below).
In Back to the Future, Doc stated that the time machine was electrical but that he needed a nuclear reaction (produced by plutonium borrowed/stolen from a group of Libyan terrorists) to generate the 1.21 gigawatts of electricity needed. This is the only film where the plutonium is mentioned. A bolt of lightning was used to power the flux capacitor twice in the series, once with a large pole and hook rigged up to the car to help Marty get back to 1985, and again accidentally in flight to send Doc to 1885. At the end of Back to the Future and in the same scene re-shot four years later in the beginning of Back to the Future Part II, we learn about the Mr. Fusion model fusion generator, made by Fusion Industries which uses garbage as fuel. It was installed in place of the nuclear reactor from the first film during Doc’s first journey thirty years into the future, 2015, when he also had the hover conversion installed. The power source of the flying components is stated in Back to the Future Part III to also be “Mr. Fusion”, but the gas engine appears to be running when the car flies. Also a different flying car can be seen getting some type of fuel pumped into it on the roof of a Texaco in 2015 in the second film. In Back to the Future Part III, the DeLorean’s fuel line was damaged during the chase by Native Americans in 1885, and Doc and Marty’s only supply of gasoline was lost. It is stated by Doc that “Mr. Fusion only powers the time circuits and the flux capacitor, but the internal combustion engine runs on ordinary gasoline. And always has.” (It is never mentioned whether Doc had any problem with the leaded gasoline of 1955; non-US-market DeLoreans ran on this fuel quite happily, so there is no reason to think that there need have been a problem). In a desperate attempt to get home, alcohol was used in place of gasoline after the fuel line was patched, destroying the seventy-three-year-old DeLorean’s fuel injection manifold. The car never traveled under its own power again, but was pulled by a team of horses and later pushed by an 1880s locomotive.