French automatic transmission manufacturer successfully takes on fiercer competition with Simcenter
PUNCH Powerglides uses Simcenter systems simulations and Simcenter Testlab to develop enhanced automatic transmissions
PUNCH Powerglide has more than 50 years of experience in the design, development and production of automatic transmissions. The company manufactures and supplies automotive components such as gears, turned parts, carriers, clutches, drums, prismatic parts and shafts all around the world.http://www.punchpowerglide.com/en
- Strasbourg, France
The automotive market is rapidly evolving against the backdrop of globalization. The market transformation involves major changes for its players. Original equipment manufacturers (OEMs) are concentrating on integration and design issues, leaving to suppliers the responsibility to develop reliable, energy-efficient, cost-optimized subsystems that meet ambitious comfort and drivability targets while adjusting to local market needs.
PUNCH Powerglide is one of these suppliers, taking up the challenge of developing driveline parts that unite excellence in performance and efficiency in fuel consumption. PUNCH Powerglide is an entrepreneurial company with more than 50 years of expertise in the design, development and production of automatic transmissions. It also manufactures and supplies automotive components such as gears, turned parts, carriers, clutches, drums, prismatic parts and shafts all around the world. The Strasbourg Technical Center (STC) hosts the research and development (R&D) department, which designs and develops new transmissions and their custom-made variants.
PUNCH Powerglide has been implementing an approach combining simulation and testing solutions in its design process for more than 15 years. By using these solutions from an early stage of development, the company can study complex systems and architectures, expand traditional design verification and reduce the number of prototypes. With the use of both test and simulation software, the company’s predictive engineering analytics streamlines the product design process while delivering quality, robustness and performance in shorter time.
PUNCH Powerglide develops six-speed automatic transmissions designed for rear-wheel or four-wheel drive vehicles both in standard (with stop and start option) and hybrid versions.
Optimizing transmission losses and comfort
To design a transmission that optimally balances energy efficiency and comfort, special focus must be given to gear shifting and to fuel economy. Inside an automatic transmission, a large amount of friction between shafts and clutch discs is unavoidable, especially during gear shifting. This friction leads to loss of energy and thus higher fuel consumption. As this point is a key engineering challenge for all car makers, reducing friction is critical for any transmission manufacturer. The key parameter is the lubrication (oil flow) of all components to reduce friction, but often too much oil flow will increase the friction instead of reducing it. The goal is to deliver the exact amount of oil needed by parts to reduce at the minimum the friction loss and also decrease the pump power required for the lubrication.
To quickly achieve a good balance of oil flow rates at the rotating part interfaces, PUNCH Powerglide uses Simcenter Amesim™ software for system simulation, from the Simcenter™ portfolio from Siemens Digital Industries Software.
The Simcenter portfolio combines 1D, 3D computer-aided engineering (CAE) and testing solutions to help with the prediction of product performance throughout the entire product lifecycle. Using Simcenter Amesim, PUNCH Powerglide can assess its lubrication system in relation to the temperature, speed and gear. The flow rate is balanced on the rotating part depending on the running conditions to be optimized, thus reducing the friction between the transmission components. These flow rates determined for each part interface become inputs of the transmission drag torque model which computes the energy saved. “Before we were using simulation in our processes, the design of the lubrication circuit took several months and required many costly prototypes. With Simcenter Amesim, the work is completed within four or five weeks, and the software enables a more precise optimization of the flow rate needed for each part in any running condition,” explains Michel Vincent, simulation engineer at PUNCH Powerglide.
Using the system simulation software, PUNCH Powerglide engineers can also precisely model the hydraulic system (valves, pistons, pumps) during the shifting phase. They reproduce some oscillations observed during the test phase to determine the effect on the shift comfort over many driving conditions.
After correlation with tests, they are able to understand the impact and role of each parameter with the design of experiments (DOE) method, and can also define an acceptable level of oscillations inside the main pressure for the outcoming and upcoming clutches. “Correlating Simcenter Amesim models with tests results and using the design of experiments technique allows us to solve problems without extensive testing sessions,” explains Vincent.
This approach makes it easier and faster for PUNCH Powerglide to find solutions to improve shifting quality, minimize friction and thus reduce the prototyping cycle. “Simcenter Amesim is used in the concept phase,” says Vincent. “Several concepts exist for the same transmission. By using system simulation, we are able to compare them and therefore gain time in the development process.”
Reaching OEM targets by lowering vibrations
In order to optimize the engine performance with a minimum amount of fuel, automotive companies are looking to downsize engines. Downsizing increases the oscillation amplitudes of the drive torque coming from the engine. PUNCH Powerglide wants to lower these oscillations to meet the OEMs’ target vibration levels and provide high-quality transmissions.
For this purpose, PUNCH Powerglide engineers rely on Simcenter Amesim to conduct noise and vibration studies. They seek to understand and analyze the torsional vibrations resulting from the drive torque for each customer’s application.
With the Simcenter solutions, PUNCH Powerglide engineers can model each customer-specific car engine and predict the exact drive torque oscillation from the engine to the automatic transmission. “We perform torsional vibration analysis for each new customer since parameters such as vehicle weight or drive torque are always different,” says Vincent. The car driveline is also modeled and simulated with Simcenter Amesim so that the company can monitor the effect of the oscillations from the transmission to the wheels.
“From the inertia/stiffness model of the car driveline and the reproduction of the engine oscillations coming through the drive torque, Simcenter Amesim helps PUNCH Powerglide select a suitable torsional vibration damper early in the development process,” says Vincent. To reduce these vibrations, an adapted damper is placed at the transmission entrance and is parameterized. Then the damper is adapted according to the customer’s demand. By using the Simcenter Amesim model, PUNCH Powerglide is able to study phenomena like shudder, rattle noise and booming noise, and also define the right damping to avoid resonance everywhere in the driveline.
The company is also saving time in its development process by understanding how the automatic transmission components will react to different oscillations. “The final goal for PUNCH is to decrease the amplitude of the oscillation everywhere along the driveline with Simcenter Amesim. Thanks to the dampers, engine vibrations can be reduced. Modelbased systems engineering is key to cost-effective and quick development,” Vincent concludes.
Tackling the challenges of globalization
Selected designs ultimately need to be verified and validated with prototype assembly and testing. The noise and vibration department team at PUNCH Powerglide makes certain that customer requirements are always met, whether they are testing the acoustic properties of a component or checking that integrated drivelines do not exceed target vibration levels.
With the impact of globalization, the team faces new challenges, as its activities expand beyond the frontiers of Europe. Matthieu Hiard, a noise, vibration and harshness (NVH) engineer at PUNCH Powerglide, sees his role and activities evolve in a global context. “We work more and more for Asian customers,” says Hiard. “We need to design our transmissions to optimize the acoustic and vibration comfort with new types of vehicles. To enhance our communication levels in a multicultural environment, we seek new, graphical ways to share information and results, showing for example operational deflection shapes or torsional animations. We aim to describe more precisely the nature of acoustic or vibration problems.”
Dealing with a wide range of vibroacoustic applications, Hiard has relied on Simcenter SCADAS™ hardware and Simcenter Testlab™ software for decades. “Simcenter testing solutions are very mature and reliable. Nowadays, we never encounter issues with those tools,” Hiard says. “Data quality is excellent and so is the data processing speed of the software.” The team uses several frontends: a Simcenter SCADAS 305 fitted with V12 modules as well as two Simcenter SCADAS Mobile hardware devices for both field and laboratory testing. With Simcenter SCADAS, the team acquires vibration and acoustic data simultaneously to controller area network (CAN) or throttle position information. “All data is stored logically in a central repository,” says Hiard. “The software makes it easy to grab the data needed for analysis.” Acquired data is then processed at high speed. “We really appreciate the flexibility of the software, for example when analyzing data in the angle domain, and the fast postprocessing, which really helps us be efficient in our daily tasks,” Hiard adds. “For acoustic analysis, we also use tools such as the audio replay and filtering, which is very helpful in understanding how airborne noise impacts acoustic comfort.”
The team also relies on the state-of the-art Simcenter Testlab modal analysis tools on a regular basis. For example, the engineers now perform the calibration of all accelerometers in-house with Simcenter Testlab. Recently, PUNCH Powerglide was asked to perform a modal analysis on the back door of a vehicle. “This is quite an unusual request for us − we are typically dealing with drivelines only,” comments Hiard. “With Simcenter testing solutions, we are able to provide a quick response and meet these requests. This is an example of how our analysis tools also support our business development. Simcenter Testlab has very exhaustive capabilities. We very much appreciate its analysis speed, its ease-ofuse and its features such as active pictures that help share information efficiently within the team,” Hiard concludes.
Developing innovative transmissions faster than ever
The use of Simcenter Amesim modelbased simulation and Simcenter Testlab test-based engineering, both part of the Simcenter portfolio, helps PUNCH Powerglide work on its innovative and complex products more efficiently, with better control over product behavior.
Modeling the transmission enables PUNCH Powerglide to optimize new transmission designs, and also to solve issues in the transmissions under development, right from the first prototype. Using a combined test-simulation approach enables the team to compare simulated and measured data for optimal results.
The new hybrid transmission 6LP2, designed with Simcenter, is the result of this innovative approach and positions PUNCH Powerglide as a top supplier of pioneering transmissions.