In the field of diesel engines, Volkswagen seems to have no rivals?
Diesel engines have many advantages, such as higher compression ratio, stronger anti-knock performance, more complete combustion, thus improving fuel economy; no need for ignition system structure is simpler, engine stability is better, maintenance cost is lower; low torque output is very strong, and it can also be widely used in heavy trucks and ships.
Diesel engine
Diesel engines have many advantages, such as higher compression ratio, stronger anti-knock performance, more complete combustion, thus improving fuel economy; no need for ignition system structure is simpler, engine stability is better, maintenance cost is lower; low torque output is very strong, and it can also be widely used in heavy trucks and ships.
These factors eventually led to the gradual decline of diesel engines in the passenger car field. In order to improve vehicle comfort, many OEMs had to abandon the use of diesel engines.
And the noise and vibration problems of diesel engines when working are also very obvious.
These factors eventually led to the gradual decline of diesel engines in the passenger car field. In order to improve vehicle comfort, many OEMs had to abandon the use of diesel engines.
GW4G15 1004016-EG01
However, Volkswagen Group does not seem willing to give up and has always maintained a keen interest in the application of diesel engines in passenger cars.
The first TDI engine
In 1989, the third-generation Audi 100 station wagon equipped with a 2.5L inline 5-cylinder TDI engine made its debut at the Frankfurt Motor Show. It has a maximum horsepower of 120 and a maximum torque of 265Nm. This is the first TDI engine launched by Audi and the world's first application of turbocharging and direct injection technology to a passenger car diesel engine.
The first generation TDI engine uses mechanically controlled pump nozzle technology. This fuel injection system is equipped with a piston pump nozzle driven by the camshaft for each cylinder. The injection pressure and accuracy depend on the camshaft rotation speed. The disadvantage is of course that the noise and vibration are relatively large.
Second-generation TDI technology
In 2004, Audi launched its first diesel engine model, the Audi A6, in the Chinese market. This 2.5L TDI engine was highly praised by domestic consumers for its excellent fuel consumption performance and excellent stability.
The second-generation Audi TDI engine uses common rail fuel injection technology. Compared with pump nozzle technology, common rail fuel injection technology is a fuel injection system controlled by a computer.
After the fuel enters the fuel rail from the electronic pump, it is distributed to each cylinder. Compared with the previous generation of camshaft-driven injector design, it not only achieves better injection accuracy and pressure control, making the TDI more powerful and with lower fuel consumption and emissions, but also greatly improves the noise problem of the diesel engine.
The second generation of Audi TDI engines has a running noise level close to that of gasoline engines. In order to vigorously promote its own TDI models, Audi installed a V12 TDI engine on the R10 racing car in 2006, with a maximum horsepower of 650 and a maximum torque of 1,200 Nm.
It achieved an unprecedented feat of three consecutive championships at the 24 Hours of Le Mans and broke many historical records.
The most shocking thing is the 2.5L diesel engine on the Audi 100, which can travel 4,800 kilometers on a tank of fuel, setting a world fuel consumption record of 1.76L per 100 kilometers.
Third-generation TDI technology
In 2008, Audi officially launched the 3.0 TDI engine, which represents the third technological innovation of TDI.
Based on the second-generation TDI engine, a combustion chamber pressure sensor and an ultra-low emission system are added, and the exhaust gas is treated in three stages through an oxidation converter, a particulate trap, and a nitrogen oxide catalytic converter.
It has solved the most challenging technical problems of diesel engines and met the European VI emission regulations scheduled to be implemented in 2014 six years ahead of schedule. It is known as the cleanest diesel engine in the world.
In addition, in Audi's TDI technology, the innovation of turbocharging technology is also crucial. Conventional superchargers need to work at higher speeds, but the speed of diesel engines is very low, which will inevitably lead to more serious turbo lag.
In order to solve this problem, Audi uses a VTG variable geometry turbocharger. The blades can adjust the geometric angle under the control of an electric switch to change the size of the force-bearing section, so that the turbocharger can intervene quickly and accurately at high and low engine speeds, increase the intake pressure, and thus enhance the engine power output.
In conclusion
Although the "diesel gate" incident once brought shame to Volkswagen's TDI technology, we have to admit that Volkswagen is definitely the most proficient and active automaker in terms of strength and enthusiasm in promoting diesel engines.
（The picture is from the Internet. If there is any infringement, please contact us to delete it.）