Innowattech :: Technical Information

Technical Information |

IPEGs harvest energy ordinarily wasted by vehicles

The energy consumed by the vehicle (sourced in the fuel combustion) utilized for a variety of applications; one of them is to overcome rolling resistance.
A typical asphalt road can be described as a visco-elastro-plastic material, with elasticity being its dominant material characteristic.
When a vehicle passes over a road, the road deflects vertically. Thi s deflection is released as thermal energy.
For a road with embedded piezoelectric generators, part of the energy the vehicle expands on roads deformation is transformed into electric energy (via direct piezoelectric effect) instead of being wasted as thermal energy (heat).

Innowattech has developed a new technology, which enables harvesting and conversion of mechanical energy of the passing vehicles, wasted throughout movement, into electrical energy.

The mechanical energy is derived from the compression stress created during the vehicles' travel on road.

Only part of the energy from the fuel combustion of the vehicle is used for moving the car along the road or run useful accessories, such as air conditioning. The rest of the energy is lost to engine inefficiencies.

The energy expended on the vehicle's movement is mainly used to overcome rolling resistance, resistance occurring when the wheel is moving forward on the road surface. In addition to the energy used to move the wheel forward (in the horizontal direction), part of the fuel combustion is wasted on creating a deformation in the asphalt, which is basically the product of the loaded wheel's influence on the road surface.

A typical asphalt road can be described as a visco-elasto-plastic material, with elasticity being its dominant material characteristic. When a vehicle passes over a road, the road deflects vertically. The deflection is proportional to the weight of the vehicle and the asphalt stiffness.

The only source for harvesting electric energy by Innowattech solution is this part of mechanical energy related to the asphalt vertical deformation, which is a percentage from the total energy of the vehicle (energy of the fuel combustion).

It is known that the vertical load of the vehicle's wheels yields compression stress, diminishing with depth. Innowattech's generators are embedded at a depth of about 5 cm; the area where the compression stressis maximal.

The external load results in the deformation in both the asphalt layer covering the generators and the generators, similar to the typical deformation in a piezoelectric column loaded under axial load.

The deformation of the generator and the shortening of the piezoelectric columns embedded in the generators, generate charges on the piezoelectric columns that are the source for the electric energy.

The energy needed to deform the road is a function of various parameters such as: the surface quality of the road, asphalt type, environment temperature and others.

Moreover, the stiffness of the piezoelectric generators is function of the piezoelectric material; thus, the weighted Young modulus of the generator is higher than that of the asphalt. When piezoelectric generators are embedded under the asphalt, the total vertical deflection of the road is decreased due to the higher Young’s modulus of the generator. It does not change the MPG of the vehicle.