New standards

Efficient intake manifold with tumble flaps

Uncompromisingly efficient: intake manifold, charge air ducts and engine cover


The world‘s first engine with variable compression comes to market in the all-new INFINITI QX50 and sets new standards when it comes to efficiency. MANN+HUMMEL is supplying almost all of the intake system on the high pressure side for the revolutionary drive system.

The first engine in the world with variable compression is impressively efficient. The drive system in the all-new INFINITI QX50 with so-called Variable Compression Turbo Engine was first presented at the 2016 Paris Motor Show and revealed as the sole power plant for the QX50 in Los Angeles ahead of the Auto Show in 2017. The 2.0 liter 4-cylinder turbo gasoline engine is able to adapt the compression of the fuel/air mix to match the respective driving situation better than ever before.

2.0 liter 4-cylinder gasoline engine with Variable Compression Turbo Technology from Nissan

Side-branch resonator

Charge air duct, hot side

Charge air duct, cold side

Engine cover

Powerful yet economic

Engineers have played with the idea of variable compression for decades, but now a breakthrough has been made possible with the use of simulation techniques and the precision of modern production machines. Up to now engine designers were forced to define a single compression ratio as a compromise solution for all driving situations which for modern gasoline engines is usually in the range of 10:1 to 14:1. INFINITI has succeeded in making this usually fixed parameter in the combustion process flexible. The variable compression removes the need for compromises. In the VC-Turbo engine, the compression is selected which best suits the respective driving situation. The change in compression depends on the driver‘s demand: at lower engine speeds a higher compression is used to increase efficiency and at higher engine speeds a lower compression prevents engine knocking under high loads. In this way the VC-Turbo engine varies the compression between 8:1 and 14:1. Thanks to VC-Turbo technology the INFINITI QX50 has an output of 200 kilowatts and a maximum torque of 390 Nm which amount to first class performance values for a 4-cylinder engine. At the same time, a real highlight is that according to the manufacturer‘s specifications its consumption is roughly ten percent lower than comparable models.

Efficiency under part-load operation

MANN+HUMMEL supplies the intake manifold, different variants of charge air ducts and the engine cover for the INFINITI QX50. The intake manifold with tumble flaps (TCV) makes a direct contribution towards the energy efficiency in the intake area. Due to high customer requirements the flaps are made from laser-welded stainless steel instead of the usually used plastic. Tumble flap systems increase efficiency in the part-load range. This is achieved by higher turbulence in the cylinder which is generated by the closed flaps. As a result the fuel/air mix combusts more quickly in the combustion chamber which in turn improves efficiency and therefore reduces fuel consumption and emissions. A contactless magnetic field sensor continuously transmits the position of the shaft of the TCV flap system to the engine control system and therefore meets the requirements for onboard diagnostics according to OBD II. A further highlight is the welded blowby pipe made from plastic. The cylinder selective introduction of blowby gas establishes a uniform distribution over all cylinders.

Premiere in the QX50

The INFINITI QX50 with VC-Turbo technology has begun sales in the United States and will soon spread to other parts of the world, including China and Europe. MANN+HUMMEL produces the intake manifold, the engine cover as well as three variants for the charge air ducts in Mexico. The charge air ducts were developed by the local team in cooperation with colleagues from the Center of Competence for this product group in Laval, France. The experts of the various MANN+HUMMEL competence centers support colleagues worldwide with the introduction of development processes and product standards. This enables a consistent quality level within the company‘s international development and production network.

For the production of the first charge air duct in Mexico, blow molding technology is used amongst others. Previously charge air ducts have been used mainly in Europe. Now that pressurized engines which require charge air ducts are in the ascendency worldwide, MANN+HUMMEL is currently establishing its blow molding process over its whole production network (see also Worldwide use of blow molding technology).

The charge air ducts fitted in the all-new INFINITI QX50 consist of injection and blow molded parts welded together which are all produced in-house. A special feature is a side-branch resonator located on the high pressure side for noise damping. This arrangement places high requirements on pressure and temperature stability. Due to a lack of installation space, however, no other position is possible. With its acoustic and production expertise MANN+HUMMEL thereby provides numerous benefits for the customer.