Vibration energy harvesters are considered as green and sustainable power supply for wireless sensor networks (WSN) used in different vehicle applications. Kinetic energy from ambient vibration is typically converted into electrical energy using electromagnetic, piezoelectric or electrostatic transducers. In comparison with other harvesters, electromagnetic transducers enable design of high power (few mill watts) low frequency (tens of Hz) harvesters. Electromagnetic harvesters can be considered as a power source for wireless sensor networks used for vehicle electronic devices. This paper demonstrates theoretically and experimentally the design procedures of electromagnetic harvesters of mechanical vibrations emitted from car engine. The research in this paper is concerned with the modeling, designing, and testing of the vibration energy electromagnetic harvesters that should be mounted on car engine. A prototype of electromagnetic energy harvester based is developed and its application in harvesting of car engines vibration is validated using a 4-cylinder in-line reciprocating engine model. The electromagnetic harvester used in this study is a single degree of freedom spring-mass system consisting of elastic cantilever with three magnets at its free tip. The analysis and investigation demonstrate that car engine harvester must be tuned to 2nd order engine speed to harvest power at either 1st or 2nd order engine speeds which allow the continuous power generation during city and highway driving.