SolidWorks Enables Innovative Auto Design

Innovation is often thought to spring from a flash of insight that occurs out of the blue. In fact, most creative designs are the product of years of work that build on linearly evolving concepts, pulling together the knowledge of the best minds in an industry. That is the case with the Ingocar, a hydraulic hybrid, whose design began in the mid 1980s.

This SolidWorks model shows the engine located in the front box of the accumulator assembly, including opposing pistons, accumulator plungers, and red and green magnets to control the fluid flow.

Ingo Valentin’s five-passenger Ingocar reduces the weight of the typical automobile platform by 50 percent. Its high-efficiency powertrain increases mileage to an incredible 170 mpg. The new combustion system is projected to reduce emissions significantly. And the unique design simplifies product planning, manufacturing, and maintenance, bringing costs down.

The Design Team
Valentin, the sole member of the Ingocar’s design team, began cultivating the expertise for this project when he developed a hydraulic motor for Hydromatik GmbH (now Bosch-Rexroth) in the mid 1970s. While he actually started the design in the 1980s, in early 2008 Valentin gleaned support from Prof. Rolf Reitz of the University of Wisconsin at Madison; Scott Goldsborough of Marquette University; Peter Achten of INNAS Corp. in The Netherlands; and Prof. Monika Ivantysynova of Purdue University.

Valentin adopted SolidWorks for its capabilities in the areas of dimensions, interference, and forces. It also enabled him to obtain data for the simulation and manufacturing of vehicle components. The software allowed Valentin to better address quality control and time-cost savings issues.

Problems and Solutions
The Ingocar is based on a new hydrostatic powertrain, with energy storage. Its main components are a new free-piston combustion engine, an accumulator to store energy, and new axial-piston wheel motors, one in each wheel. The accumulator is the load-carrying backbone of the car, and the engine, wheels, and active bumper system are attached to it. The car body is simplified and significantly lighter because the road forces are carried by the accumulator.

The hydraulic engine pumps fluid into the accumulator and turns off automatically when the accumulator is fully charged. The pressurized fluid drives the wheel motors. When braking, the motors are reversed and recoup the braking energy by pumping the fluid back into the accumulator. The round-trip-efficiency during braking is about 75 percent. Therefore, energy is consumed only to overcome the rolling resistance of the tires and the air drag of the car.

The free-piston engine (38 hp) operates at nearly constant speed and power when charging the accumulator. A new circumferential fuel injection system, with ultra-high injection pressure (50,000 psi) and a pressure wave charger mechanism, improves the thermal efficiency and power density of the engine. This reduces both fuel consumption and emissions significantly. How big an impact it will have depends on how willing car makers are to accept this level of change. And change never comes easy.