In the second part of the blog on the history of the intake manifold, Heinz Bühl, product champion for intake manifolds and Herbert Pietrowski, senior product expert for intake manifolds report on the market progress of the intake manifold and the bright prospects for the future.

More complexity

After the introduction of plastic core technology (end of the 1980s) and changeover to the low-cost multi-shell technology (mid-1990s), the third phase of the development of the intake manifold was the phase of increasingly complex solutions. The components now started to include additional functions such as duct length switching and charge movement flaps, also known to insiders as tumble flaps.

Variable-length intake manifold for Audi with tumble flaps (2004)

This enables us to give customers the possibility of influencing the air charge to the cylinder, which in turn reduces emissions. These flaps usually find application in petrol engines. Diesel engines, on the other hand, generally have a duct switch-off function where one of two cylinder inlet ducts can be closed. This serves to increase the possible speed range of the engine. This was a decisive point in the development of the high performance diesel engines as we know them today.

Intake manifold module with duct switch-off for Ford (2003)

A number of new products were introduced in succession: in 2002 the first diesel variable length intake manifold in plastic with EGR cooler, the first intake manifold with integrated cylinder hood and oil separator and the first cylinder hood module with integrated variable-length intake manifold in 2003, the world’s first modular intake manifold, active and passive in 2006, the first intake manifold with designer surface and hidden welding seam in 2007 and an intake manifold with integrated mounting plate for the control unit in 2009.

Around 2010 complex intake modules entered a particularly difficult phase. This was triggered by the popularity of downsizing and turbocharged engines emerged which for the time being did not require variable-length intake manifolds. The intake system ceased to be an intake system, but was merely a simple air induction system with a complex switching function with just two shells to make a finished product. At that time the significance of the intake manifold went down considerably, but due to new developments in the last five years the intake manifold is currently enjoying a renaissance.

Intake manifold production in Sonneberg (Thueringen)

Renaissance of the switching technology

The exhaust gas legislation Euro 6, Euro 6.2 and Euro 7 had led once again to more demand for variability within the intake system. At the present time, as well as observing the European driving cycle (NEDC), we also take the subject of real driving emissions into account. At the start of 2016 the EU parliament decided on the introduction of emission measurements under real driving conditions and the introduction of a new test cycle (WLTP) in 2017. According to VDA president Wissmann the decision is ambitious and represents a significant technical challenge for car producers and suppliers.

The decision means that the car engine has to meet the requirements of the exhaust gas legislation over the cycle and also at each load point. As a result, in addition to the important area of low-end torque, the driving forces in the development of engines today are less CO2, lower consumption and lower emissions under test conditions and also under real driving conditions. There will be many developments in this respect in the coming years. The requirements are known and the manufacturers know that they need further products for the purpose of compliance.

Active intake manifold with integrated intercooling and electrical booster compressor

That means we now once again need variability in the intake system. We can improve the intake system to make a significant contribution towards reducing exhaust emissions and reducing CO2 for the customer – and all for an attractive price. Therefore, in this area we are once again on track. Complex intake manifold systems with a number of integrated functions are up and coming such as tumble flaps or integrated intercoolers.

The significance of the systems is therefore increasing and the R&D work in this field has become more important again. And that is where our strength lies. The manpower in our R&D network is one of our most important and greatest resources.

One example of the potential offered by intake systems is our current high-end product, the active intake manifold with integrated intercooling, electrical booster compressor and tumble flaps. That is not a dream or a vision, but is a definite product for the next few years.