Reducing the mass of the car is one way to reduce fuel consumption, and the motor is an essential heavy part of the car. Reduced CO2 emissions and reduced weight of the engine – both are promised by a new type of plastic camshaft module, which the Fraunhofer Institute for Chemical Technology ICT has now introduced.
In collaboration with their partners, the research team has succeeded in manufacturing a camshaft module from fiber-reinforced thermoset polymers that weigh less. And due to the fact that the cover is located at the top of the engine, this not only reduces the total weight of the motor but also reduces its center of mass.
To date, the camshafts are mounted in a module that is still made of aluminum. The aluminum cast cover has greater rigidity, with a similar weight. However, the plastic part is much lighter, not inferior in strength, and more effectively counteracts noise. The high-strength, fiber-reinforced thermosets can withstand high temperatures, mechanical and chemical loads, such as those caused by synthetic engine oils and coolants.
Among the other advantages of a plastic part is it minimizes the noise. The NVH properties (noise, vibration, harshness) – a combination of noise, vibration, and roughness – are high on the list of factors that are used to assess vehicle quality. The post-processing of fiber-reinforced thermosets is comparatively low; they can be produced close to the final contour, which is associated with lower production costs.
In addition, reinforced plastics with a high fiber content have a significantly lower CO2 footprint compared to aluminum, since the light metal is very energy-intensive to manufacture. It should be noted that the thermosetting polymer reinforced with fiber has only a quarter of the stiffness of aluminum; however, the design of the camshaft module is said to compensate for this drawback.
“We contribute the know-how regarding how to design the component geometries to suit the material and the process so that they satisfy all requirements,” says Thomas Sorg, a researcher at Fraunhofer ICT. “The camshaft module is located in the cylinder head, so normally in the upper installation space of the powertrain. Here, it makes particular sense to reduce weight since doing so also contributes to lowering the vehicle’s center of gravity.”
The developers claim that the test prototype “demonstrated flawless functionality in a state-of-the-art internal combustion engine” after 600 hours of testing on the engine test stand. To introduce a new development into production vehicles, additional research and certification are needed, but the intermediate results look promising.