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Brief description

Brief description

Description

Z19DT/DTH

Unlike a conventional aspirating engine, a supercharged engine has improved filling during the induction stroke, which means more efficient combustion, higher power, higher torque and lower fuel consumption. This all adds up to a performance comparable with a larger engine, while retaining the advantages of a smaller one with regard to fuel economy, space, weight, etc.

Supercharging is done using a turbocharger, which uses the engine exhaust gas to drive it. Exhaust gas is led into a turbine housing with variable vanes (VNT, Variable Nozzle Turbine).

The engine exhaust makes a turbine wheel rotate. The turbine wheel is in direct contact with a compressor impeller, which means the compressor impeller rotates at the same speed as the turbine wheel. The compressor impeller increases the pressure in the induction system, which means more air is entering the engine. This makes it possible to burn more fuel, resulting in higher torque and power. The engine control module regulates this process by checking the position of the vanes, amongst other things.

The vane opening is adapted for a particular running condition, usually with a small opening for low engine loads. For high engine loads, the vanes will open up to regulate the turbine speed and thereby also the degree of supercharging.

The turbo is designed to start working even at relatively low engine speeds, which gives the engine a high torque in speed ranges that are used in normal driving conditions. The high torque and short turbo delay make the car smooth and comfortable to drive.

The turbocharger turbine housing is integrated in one unit with the engine exhaust manifold.

Z19DTR

Unlike a conventional aspirating engine, a supercharged engine has improved filling during the induction stroke, which means more efficient combustion, higher power, higher torque and lower fuel consumption. This all adds up to a performance comparable with a larger engine, while retaining the advantages of a smaller one with regard to fuel economy, space, weight, etc.

Supercharging is done using two turbochargers - one small and one large - with the engine exhaust gas used as the driving energy. Depending on the operating conditions, there is a pressure increase in the small turbocharger, both or the large turbocharger only. The exhaust gas flow through the turbines of the two turbochargers is regulated by wastegates which lead the gases past the turbine as necessary. The turbine housings have fixed geometry (not VNT).

The engine exhaust makes a turbine wheel rotate. The turbine wheel is in direct contact with a compressor impeller via a shaft, which means the compressor impeller rotates at the same speed as the turbine wheel. The compressor impeller increases the pressure in the induction system, which means more air enters the engine. This makes it possible to burn more fuel, resulting in higher torque and power. The engine control module regulates this process through measures such as regulating wastegate position.

The opening of the wastegates is regulated by ECM based on prevailing driving conditions, usually with little or no opening at low engine load. At high engine load, when there is an excess of exhaust gases, the wastegate opens and the gases bypass the turbine. This makes it possible to regulate turbine speed and thereby regulate the degree of supercharging.

When designing a supercharger system with turbo, the designer must often make comprises between providing the system capacity for high max. engine power and good properties at low engine speeds. Both aspects are usually compromised. He or she could choose a small turbocharger with good performance and quick response at low/moderate engine speeds and loads. The disadvantage is that the turbocharger cannot provide sufficient air at higher engine speeds/loads. A larger turbocharger would fix this, but at the expense of positive properties at low engine speeds.

TwinTurbo technology combines the best of both worlds - a small turbo that gives the engine high torque and quick reaction capability at low engine speeds and a large turbo that works effectively at high output.

At low engine speed, boost pressure is built up by the small turbocharger. In the intermediate range, both compressors work in series, with the large turbocharger supplying a certain pressure increase to the small one, which increases the pressure even more. In the upper part of the intermediate range, the wastegate flap of the small turbo is open so wide that the majority of the exhaust gases bypass the exhaust turbine. Turbine speed drops and the large turbocharger takes over. At this time, a (pneumatic) check valve connected via the small turbo's compressor opens and the charge air from the large turbo is led past the small turbo's compressor.

The small turbo is called the "high-pressure turbo" while the large one is called the "low-pressure turbo".

The turbo system is designed to start working even at very low engine speeds, which gives the engine a high torque in speed ranges that are used in normal driving conditions. The high torque and short turbo delay make the car smooth and comfortable to drive.

The exhaust manifold is integrated with the small turbo (high-pressure turbo). The large turbo (low-pressure turbo) is screwed to the turbine outlet of the small turbo.