Energy Harvesting, or how to recover part of the energy from the environment, which would otherwise be lost and convert it into another usable form of energy, like electricity. We will see in this article an original idea to convert into electricity the energy produced by the shock absorbers of vehicles.
Energy harvesting is a theme of great importance worldwide, especially in these times of ever increasing energy costs. This blog has always reserved a prominent relevance to this subject, with particular emphasis on contributions made in the specific field of electronics (think for example to the products developed by Linear Technology). In this article we will see instead a technique invented and developed by an American startup, which goal is to convert the energy produced by a vehicle shock absorbers movements into electrical energy, allowing significant fuel savings.
This is the name of the company, founded by a group of MIT researchers and headquartered in Cambridge (Massachusetts), that developed the product with which it is possible to obtain a fuel saving between 1.5 and 6%, depending on the vehicle and on the driving conditions. Moreover, the researchers say that this system can improve the stability of the vehicle. Levant has demonstrated the validity of the developed technology through road tests performed by a Humvee, and plans to extend the tests involving other types of vehicles such as trucks, buses and other vehicles.
The GenShock shock absorber
These new types of shocks, called GenShock, are outwardly comparable to the conventional ones, except for an electric cable that comes out by them, and they can be installed in ordinary vehicles from a common mechanic. The shock absorbers are connected to a power management system that can interface with other sources of power, such as regenerative braking systems, thermoelectric devices that can convert waste heat into electricity, or even solar panels.
The energy produced by the shock absorbers is then placed in the electrical circuit of the vehicle, thus reducing the load on the alternator. In the following images are shown, respectively, the external appearance of the shock absorbers and the various parts they are composed of. The shock absorber works just like a conventional model, except that its head has been modified to include a mechanism that rotates while the piston moves up and down within the oil, effectively creating a tiny generator.
It is also present a sophisticated electronic control unit that, basing on the information coming from accelerometers and other sensors, is able to modify the hardness of the shock absorbers, thus improving the stability of the vehicle. For example, if you are going to take a corner to the left, the system will automatically stiffen the shock absorbers on the right side, thus improving the cornering stability.
The system works best for heavy and off-road vehicles, especially when they move quickly on rough terrain, and among the possible applications it is not excluded the use in some military vehicle. In order to contain costs as much as possible, the shock absorbers are built using mostly components already available on the market. They want, therefore, to avoid repeating the failure experienced time ago by the active suspensions, which were practically discarded because of their costs too high for conventional vehicles. Levant's aim is not to produce directly the shock absorbers, but rather to grant licenses for their manufacturing.
Particularly interesting is the following video, related with the GenShock technology:
Today, some hybrid vehicle is already able to recover energy from the braking, but none so far had ever thought to recover energy from the shock absorbers. The amount of recoverable energy is much higher the greater is the vehicle mass, so the best benefits are obtained with heavy vehicles or with whicle such as Humvee. Tests carried out on a truck equipped with 6 shock absorbers have shown that each shock can produce even 1kW of power while traveling on a normal road, a considerable amount of energy able to reduce the load to the alternator and provide power to other units such as an air conditioner.
Such systems could have a future, taking into account that only 20% of the energy produced by fuel combustion is actually used to move the vehicle, and part of the energy not used is lost in the suspension system and in the shock absorbers. The additional cost involved with the GenShock technology, compared with the cost relate dto the traditional solution, may be depreciated, according to Levant Power engineers, in about a year, thanks to the savings in fuel that this solution entails. In addition, this technology extends the life of many vehicle components, including, first and foremost, suspensions, and allows the installation on the vehicle of smaller, lighter, and cheaper alternators. It is also a solution suitable for use in hybrid and electric vehicles.