Design and Experimentation of Energy Harvesting using Shock Absorber

Transportation accounts for 70% of oil consumption, and yet only 10-20% the fuel energy is used for vehicle mobility. One of the important losses is the energy dissipation in suspension vibration. The objectives of this thesis are to investigate energy recovery from vehicle suspensions by answering two questions: (1) how much energy is available while meeting the primary functions of shock absorbers? (2) How can the wasted energy be converted efficiently to electricity? To answer the first question, a vehicle-ground model, including the stochastic property of road roughness, vehicle parameters, travelling speed, is created with analysis of ride comfort, road safety, and vibration energy induced by road roughness. We found that the dissipative power from all four shock absorbers for a typical mid-size passenger car on ISO class B (good), C (average), and D (poor) roads are approximately 100, 400, 1600 Watts respectively. The sensitivity of the power generation, ride comfort and ride safety to various operational vehicle parameters are further analysed. Results indicate the power generation is mainly depended on the tire stiffness in which the higher tire stiffness is, the more power generation. However, higher tire stiffness will cause a less comfort and more dangerous ride. Therefore, larger sprung mass will be preferred for achieving a more comfort and safer ride to compromise the negative effects of high tire stiffness. More importantly, the suspension damping also plays as an important role on ride comfort and safety aspects. A more comfortable ride can be accomplished with softer damper. As a trade-off, the probability of losing ground contact increases which will cause handling issues and safety hazards.