John is a mechanical engineer.He has designed a car which uses water rather than fossil fuel to run.Is John's invention eligible to be patented?

Yes.To qualify for a patent,an invention must meet three requirements.John's invention is a machine and,therefore,it fulfils the statute of "patentable subject matter." John's invention is also useful,as this feature was not known before this particular device.Thirdly,the application designed is so clear that individuals who are educated and experienced in the field can create the device on their own.Therefore,John's invention can be patented.