Issue 01/2007 Porsche Engineering Magazine Success all along the line The victory year of the RS Spyder, a motorsports development makes history Chain forces Integrated simulation mode for improved tuning of indi- vidual components Torsional vibration measurements Tracking down transmission noises Editorial Dear Readers: Technical progress is made possible by an eye for detail. Driven by unceasing curiosity, it is also the prerequisite for our favorite activities: questioning, researching, inventing. These three components drive our transmissions. Even the sports engine guarantees peak perform- work. For the customer, we convert watercraft Seabob was built with ance – and not just in sports cars. them into actual motion. They are the help of the Porsche Engineering the driving forces that help us put Group. Our experts gave its insides Finally, we would like to look back into practice scientific findings, for a complete electronic makeover and present our achievements for you and your projects. The aspira- that promises pure driving pleasure. 2007. The RS Spyder is a success tion to be the driving force that model from Porsche and also a creates the future and enables Driven by an innovative spirit, our driving force in motor sports. The progress, motivates our engineers, employees try to use familiar raw winner of the American Le Mans day after day. materials in new ways, not limiting Series ALMS features convincing their knowledge to just one per- advanced technology, outstanding In this issue, dear readers, we spective. The use of aluminum for driving performance and unique would like to present to you our the doors of the 911 and the devel- dynamics. We can without a doubt work using examples and current opment of a solar module provide be proud – of the car and an out- developments around the topics of impressive proof of that. standing racing season 2007! “driving forces” and “drive”. In engine development, dynamics Please join us on a brief journey Our engineers’ tasks include identi- and drive also play an important through our current development fying the slightest of influences – role. Porsche Engineering presents work and discover the driving such as gearing in wheel drives – the new measuring methods for the forces at Porsche Engineering thereby perfecting the mechanisms. dynamic behavior of valve drives. Group. Their work represents a major con- Because only a optimally tuned tribution to noise optimization in Enjoy reading, The Editorial Team 2 Porsche Engineering Magazine 01/2007 Contents Contents Page News Porsche Engineering current events 4 Engine Tracking down ambient noises with torsional vibration measurements 5 Drivetrain Valve drive measurements to optimize the dynamic behavior of valve drives 8 Drivetrain Integrated simulations for calculating chain forces 10 Body & Safety Aluminum – a weighty decision made easy 12 Electrics & Electronics Environmentally friendly thrills in the water thanks to Porsche Engineering developments 16 Insights RS Spyder 18 Lohner Porsche 22 Porsche Engineering Magazine 01/2007 3 News About Porsche Engineering At Porsche Engineering, engineers ing production start-up manage- Weissach – and yet it is globally work meticulously on new, unusual ment. What makes it special: All available. Of course, also directly at ideas for vehicles and industrial this is done with the expertise of a your site. But regardless of where products. Upon request from auto- series manufacturer. You need an we work, we always bring a piece motive manufacturers and suppli- automotive developer for your pro- of Porsche Engineering with us. ers, we develop a variety of solu- ject? Or do you prefer a specialized tions – ranging from the design of system developer? We offer both - If you would like to learn more individual components through the because Porsche Engineering about us, please request our image layout of complex modules to the works where both areas interface. brochure by e-mail: planning and implementation of The extensive knowledge of entire vehicle developments includ- Porsche Engineering converges in [email protected] I Porsche Engineering Insights High demand for developments Focus on alternative ensures well-filled order books technologies, such as hybrid for 2008 and electric drives The high demand for development Forward-looking innovations are the services from Porsche Engineering objective of all development engi- is unrestrained. Short development neers at Porsche Engineering times, technical innovations and Group GmbH. New drive concepts sustainable cost reductions are at are a focal point of the develop- the top of the customers’ list of ment work of Porsche Engineering requirements. For 2008, the order Group. The engineers have been books of Porsche Engineering are very active in the area of alternative full once again. drives, such as hybrid and electric engines and have specialized even Customized solutions for automo- further in this field. tive manufacturers and suppliers, but also companies in other indus- In 2008, there will also be projects tries, are the objective of the devel- concerning further improvements of opment work. We would like to the new drive technologies – as thank our customers for their trust always strictly confidential, for the and look forward to an innovative benefit of our customers. I new year. I 4 Porsche Engineering Magazine 01/2007 Tracking down drive noises Engine Torsional vibration measurements are a reliable method for finding noise in the drivetrain 3. Torsional vibration measurements on the drivetrain 1. Airborne sound measurement 2. Structure-borne sound in the interior in the engine All Dr. Ing. h.c. F. Porsche AG vehicles are developed and manufactured according to the highest quality standards. This includes the acoustics, a topic that is an important focus for our development departments. Dominant sources of noise that the Mechanical causes of noises, they resemble “whining” or driver can hear are – besides body transmission noise “whistling”. and chassis – the drivetrain and the transmission. Minimizing these Transmission noise is caused main- In order to measure noise, air-borne transmission noises has for many ly by loads on the intermeshing sound measurements (point 1, Fig. years been an important challenge teeth. In particular, rigidity fluctua- above) are performed in the interior for the development engineers of tions during meshing are responsi- of the vehicle, where the noises Porsche Engineering. ble for this. These fluctuations perceived by the passengers can cause rotational irregularity during be measured. However, the meas- The knowledge about modern the transmission of the rotary ured noises may be superimposed measuring methods that can local- motion. If the rotational irregulari- by other noises of a similar order ize and ultimately minimize these ties caused by the gearing are (e.g., engine noises). To obtain the noises is thus gaining importance. introduced into the drivetrain, they amplitudes of a vibration directly at Only if noise can be located with can be transmitted to the vehicle in the engine, structure-borne sound suitable measurements can the the form of structure-born vibration. measurements are performed on mechanical causes of undesirable Therefore, they are often audible in the engine (point 2, Fig. above). drivetrain noises and vibration (such the interior. Depending on the fre- as whining or whistling in the trans- quency of these relatively tonal mission) be eliminated. Porsche Engineering Magazine 01/2007 5 Tracking down drive noises Engine However, these two measuring methods alone do not satisfy the Engine speed range of the phenomenon experts at Porsche Engineering, since they do not yield a thorough Structure-borne sound root cause analysis of a transmis- 0.2 g sion noise. Therefore, they devel- oped a system for measuring the 20000 degrees/(s*s) Acceleration root causes of gearing noises ular acceleration, rms directly on the drivetrain – in the g Right flange An smallest of installation spaces and Input shaft at high temperatures (point 3, Right wheel Engine speed [rpm] Fig. p. 5). 500 rpm High-resolution torsional Angular acceleration at different engine speeds and measuring points for accurate localiza- vibration measurement on the tion of engine noises. drivetrain of freedom of the rolling test stand The measuring technology used Torsional vibration measurements for special studies and to simulate here has been validated, the time provide information about vibration the on-road operation of the vehi- resolution and the number of meas- that is superimposed on a regular cle. urement sensors is sufficient to rotational movement. This allows detect even very small rotational the transmission noises caused by Over several measurement series, variations. Using a system that the meshing to be measured. the parameters load, driving gear accurately detects the time inter- and transmission oil temperature vals between the measurement The high-resolution torsional vibra- are varied. Furthermore, the effect points of the sensors on rotating tion measurement is performed in of a component can be examined axles and gears allows an analysis the anechoic chambers of the (e.g., axle shafts with different with precise separation of frequen- Development Center in Weissach. mass moments of inertia). In addi- cies. By optimizing the sensor ele- The analyses make the measure- tion, traction and overrun (full load) ments for high resolution, rotational ments reproducible, especially for load conditions