FKFS Veranstaltungen

2025 Stuttgart International Symposium
on Automotive and Engine Technology

3. - 4. Juli 2025

Session: Development Methods I | | 15:00 - 15:30

Measuring Change of Inner Energy with Force

Daniel Puscher, FKFS

Today’s Components are getting more and more efficient. The higher the efficiency, the smaller the steps in efficiency gain is between two development steps. This is challenging measuring techniques and equipment to prove these small gains. The calculation of efficiency can be carried out using power loss and power input. This method has advantages in measuring uncertainty when efficiency increases. One way to measure power loss of a device is to measure the rejected heat with calorimetric measurement methods. The main disadvantage is that the change of the temperature field (inner energy) has to be constant. When this state is reached, the rejected heat over the surface is equal to the internally produced power loss. This takes mostly a long time. The challenge of getting faster in measurement is hence to measure the change of the inner energy simultaneously to the rejected heat over the surface of the device. One part of the inner energy of technical devices can be a metal housing. The inner energy of metals, with respect to heat accumulation, is proportional to their temperature. When temperature of metals is changed, they tend to change their volume over the linear thermal expansion coefficient too. To suppress this expansion, a force is necessary. This reaction force can be measured with force sensors. The paper concentrates to investigate the potential of this Method to measure the change in inner energy.