ProductLMS

Business challengesDesign hydraulic transformer built specifically for hybrid drivetrainSimplify multi-domain integration

Keys to success Use LMS Amesim, especially leveraging its hydraulic component design library

Results Simplified operations/best practicesDecreased noise level generated by the hydraulic transformerDeveloped “Floating Cup” design faster Enhanced fluid modeling capabilitiesNotably accelerated development turnaround

Siemens PLM Software solution enables Innas to save considerable product development time

Developing a hydraulic hybridEvery automotive maker is busy with hybrid vehicles. It is the current buzzword in the automotive industry, and it seems that consumers are putting their money behind this new technology. For instance, the electric hybrid Honda Insight ranked as the top-selling vehicle in Japan in April 2009, the first time a hybrid has secured such a lofty position. But these are early days for hybrid technology and there are many innovative ideas emerging to pro-duce better, more intelligent and efficient hybrid solutions.

Innas is an independent engineer- ing firm specializing in innovative product development. It has a different take on the standard gas-electric hybrid engine. During the past ten years, Innas has been devoted to the development of a hydraulic hybrid. They see it as a better solution since the hydraulic accumulator is far more efficient than an electric battery, especially at high power rates, and the power density of hydraulic motors is greater than electric motors. Moreover, the hydraulic system adds less weight to a vehicle than an electric system.

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InnasEngineering firm designs innovative “HyDrid” engine solution using LMS Imagine.Lab Amesim

The fundamental principle behind hybrid vehicles is the storing of energy in an accumulator that can subsequently be used to power the vehicle. In the Innas “HyDrid” concept, a fixed displacement hydraulic pump, connected to the internal combustion engine, is used to charge the accumulator. When it is full, the engine is switched off. The car is then propelled on stored energy until it runs out, at which point the engine is engaged once more and the accumulator is refilled. A hydraulic transformer converts the pressure level in the accumulator to the level required by the hydrostatic wheel motors.

“A hydraulic transformer converts the input pressure into output pressure and

functions as a clever integration of motor and pump,” says Titus van den Brink, a project leader at Innas. “The pressure in the accumulator varies as it is loaded and unloaded. Hydraulic motors are connected to the wheels and demand a certain pres-sure depending on car speed, road inclina-tion and acceleration.

Retaining and returning energy“That pressure is not necessarily equal to the accumulator pressure. The hydraulic transformer converts the accumulator pressure to the required pressure for the

wheel motors. The transformer can even amplify the pressure, boosting the wheel torque with small, simple and robust con-stant displacement wheel motors.”

Another advantage of the transformer is that it uses the energy released when braking to load the accumulator. This is known as regenerative braking: “Normally, the kinetic energy generated from braking is lost in the heat of the brake discs, but with a transformer you can retain this energy and return it to the accumulator,” says van den Brink.

“With Siemens PLM Software (technology), we increased the development speed considerably. LMS Amesim made all the difference.”Titus van den Brink Project Leader Innas

“We needed a good solver for a complex hydraulic machine with a high num-ber of pistons and shuttle valves. For this we used LMS Amesim fluid modeling capabilities. By providing an easy-to-use framework, this 1D simula-tion platform was able to simplify multi-domain integration for us.”

Titus van den Brink Project Leader Innas

Managing complexityInnas has worked on the development of its hydraulic transformer for more than 10 years, culminating in the recent design of a transformer built specifically for hydrau-lic hybrid drive trains. When it was time for the company to model its hydraulic trans-former, Innas selected LMS Imagine.Lab Amesim™ software from Siemens PLM Software. “We needed a good solver for a complex hydraulic machine with a high number of pistons and shuttle valves,” says van den Brink. “For this we used LMS Amesim fluids modeling capabilities. By providing an easy-to-use framework, this 1D simulation platform was able to simplify multi-domain integration for us.” Innas originally attempted to undertake its modeling by using another tool, but this proved to be difficult. “You had to create your own model in the other solution,” says van den Brink. “If you did it well it would function well, but it wasn’t easy to develop a robust system simulation model. LMS Amesim was a more specialized and better solver for the system. This was a big advantage for us. For example, with LMS

Amesim, the oil model is done for you. You can simply say there is 0.2 percent air in the oil and that’s it.”

Saving timeInnas used the hydraulic component design (HCD) library of LMS Amesim, which has a collection of 3,500 compo-nents that can be used to build the machine. All users had to do was simply

“LMS Amesim was a more specialized and better solver for the system. This was a big advantage for us. For example, with LMS Amesim, the oil model is done for you. You can simply say there is 0.2 percent air in the oil and that’s it.”Titus van den Brink Project Leader Innas

connect validated components in order to accurately predict multi-disciplinary intelli-gent system performance.

“We tried to model with the other solution, but it simply didn’t work, so we stopped,” says van den Brink. “There’s no doubt that the use of LMS Amesim saved us a consid-erable amount of time.”

Making the differenceIn the past, hydraulic motors and pumps have not been regarded as appropriate for use in passenger cars due to high noise levels, high torque variations and poor effi-ciency, especially under part-load operat-ing conditions. With the help of Siemens PLM Software technology, Innas’ innova-tive new design overcomes such disadvantages.

“When we developed this transformer, we started with conventional displacement machines that have a limited number of pistons,” says van den Brink. “What we needed was a displacement machine with more pistons, which is why we developed one with 24, known as the ‘Floating Cup’ design. With this many pistons the flow pulsation is decreased, as is the noise.”

The engineer believes that Innas would not have been able to complete the Floating Cup design in the same timeframe without Siemens PLM Software: “With Siemens PLM Software (technology), we increased the development speed consid-erably,” says van den Brink. “LMS Amesim made all the difference.”

Solutions/ServicesLMS Imagine.Lab Amesim www.siemens.com/plm/lms-amesim

Customer’s primary businessInnas is an independent engineering company that has gained an international reputation by achieving innovative developments in hydraulic components, hydrau-lic drives and combustion engines. Innas works with organizations that are active in the field of industrial vehicles, mobile equipment, combustion engines and hydraulic drives and components. www.innas.com

Customer location Breda Netherlands

Siemens PLM Software Americas +1 248 952 5664Europe +32 16 384 200Asia-Pacific +852 2230 3308

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