Double vortex tube single turbine technology

When it comes to turbocharging, it is still a simple and common single-scroll turbocharger in people's minds. Today's technology is changing with each passing day, and a new generation of twin scroll single turbines has been applied to the latest high-end turbocharged models. What kind of performance enhancement is brought about by the new generation of technology? Today, we will discuss the technology of the twin scroll single turbine.

The twin scroll turbocharger is designed with two exhaust ports. The middle turbine compartment divides the exhaust port into two parts. The difference from the common single scroll supercharger is shown in the figure. The turbine on the left is an ordinary single-scroll single turbine with only one exhaust port. The right-side turbine is a double-scroll single turbine with two exhaust ports.

We all know that the firing order of a four-cylinder engine is generally 1-3-4-2 cylinders. The exhaust manifold of a single-scroll turbocharger (commonly known as exhaust banana) connects all the exhaust pipes of the cylinders. After the summary, blow to the turbine. This design is simple, low cost, and durable, but this design produces a pulse resonance of the gas when working in a single cylinder, affecting the exhaust efficiency of other cylinders, and increasing the back pressure of the next cylinder to be operated. When the cylinder is working, the intake and exhaust valves of the cylinder are open for a period of overlapping time. At this time, the next cylinder has already been ignited and exhausted. In this very short period of time, if the 1 and 3 cylinder exhaust pipes are connected, This will cause the air intake of the previous cylinder to decrease. This leads to a decrease in the total power of the next cycle.

The twin-scroll turbocharger completely eliminates the problem of high intake air drop caused by excessive back pressure. As shown in the figure below, the 1-cylinder and 4-cylinder exhaust are exhausted through a vortex tube. The 2-cylinder and 3-cylinder are exhausted through another vortex tube. The two sets of exhaust gases are incoherent. When one cylinder completes the work cycle, the next three cylinders do work. Since the exhaust pipes of the 1 cylinder and the 3 cylinder are not connected, there is no interference effect between them. After the completion of the 3-cylinder work, the 4-cylinder work is done, and there is no interference with each other. The 4-cylinder is followed by the 2-cylinder. The cycle is repeated. Each work and intake is not affected, and the maximum intake air amount is achieved. The efficiency of the intake air combustion is 7% to 8% higher than that of a common single scroll supercharger, which means that the performance is improved by 7% to 8% compared with a single scroll turbine. At the same time, due to the increase in efficiency, the fuel required to complete the same acceleration performance is smaller, increasing fuel economy.

In-line six-cylinder twin scroll single turbocharged engine:

The BMW N55 3.0T engine is an in-line six-cylinder engine that also uses twin-scroll turbines. The cross section is shown in the figure below. The double scroll can be clearly seen. The ignition sequence of Straight 6 and Straight 4 is different. The ignition sequence of straight 6 is generally 1-5-3-6-2-4, that is to say: the arrangement of straight 6 is a group of 123 cylinders and a group of 456 cylinders. In this way, each cylinder does not affect the work of the next cylinder.

The new Regal 2.0T, straight four, also used a twin scroll turbine. The horsepower reaches 220 horsepower/torque 350 Nm. The double vortex tube technology allows the new Regal to have a torque of 350 Nm, which cannot be reached easily with the 2.0T of the same grade single vortex tube.

BMW MINI 1.6T, straight four, equipped with a twin-scroll turbo engine, the maximum horsepower 184 horses, the maximum torque of 240 Nm.

Another more advanced engine is the modern 2.0T GDI direct injection double scroll single turbo engine. At present, the engine is equipped with the US version of the 8th generation Sonata, as well as the US version K5, Zhi Run. This modern direct-injection double-scroller engine is extremely efficient, achieving a maximum horsepower of 274 HP and a maximum torque of 366 Nm (269 pound-feet). The US version of the 8th generation Sonata has a 100 km acceleration within 6.5 seconds.

In the future, more and more turbines will be equipped with twin scroll turbines to increase efficiency. Let us wait and see!