Taking stock of the top 10 popular engine technologies, the last one can be called a "unique skill"!

The engine can be said to be the "soul" of a car. After continuous improvements and upgrades, today's engine is no longer as simple as just being able to run. Under the dual requirements of power and fuel economy, the engine may have long become a "work of art" in the eyes of car lovers!

Today we are going to talk about the 10 most popular technologies in engines!

1. Turbocharger

Turbocharging should be one of the most familiar technologies, but nowadays, car companies are no longer satisfied with simply "adding a turbo". After all, low-end and mid-range models are studying "small inertia turbo" to suppress turbo lag, and mid-to-high-end models are studying "variable section turbo" and "electric turbo" (such as Porsche/Audi) to meet the needs of various engine speed ranges. According to the current situation, turbocharging will further occupy the position of naturally aspirated.

2. Direct injection

Direct injection is one of the technologies that many turbocharged engines rely on. As the name suggests, direct injection is to move the fuel injector that was previously located in the intake manifold to the cylinder. The advantage of this is that the air-fuel ratio can be accurately controlled to make the combustion more complete. The characteristics of direct injection engines are low fuel consumption and high power per liter, such as the Honda Earth Dream series.

3. Stratified combustion

The characteristic of stratified combustion technology is that the concentration of the mixed gas in the engine cylinder is not uniform. The mixed gas is thinner in the cylinder away from the spark plug and thicker in the cylinder near the spark plug. This requires the engine to implement two injections (intake and compression stroke) or use special injection nozzles. Stratified combustion technology can fully squeeze the fuel power and achieve higher thermal efficiency. Audi's TFSI is a representative example.

4. Dual overhead camshaft

Corresponding to the dual overhead camshaft (DOHC) is the single overhead camshaft (SOHC). The overhead camshaft can shorten the distance between the camshaft and the valve, simplify the transmission mechanism, and make the engine more compact. At the same time, combined with the multi-valve design, the dual overhead camshaft engine can more easily and accurately control the intake and exhaust valve time difference and obtain greater power. At present, DOHC has become the mainstream.

5. Variable Valve Timing

Variable valve timing technology is no longer rare today, and all mainstream car companies have their own masterpieces, such as the well-known Toyota VVT-i, Honda i-VTEC, Mitsubishi MIVEC, etc. Variable valve timing technology is to control and adjust the cam so that the valve opening and closing time is better matched with the engine speed, so as to reduce fuel consumption and increase engine power.

6. 48V Mild Hybrid System

48V mild hybrid models have gradually become popular in the past two years. The idea is relatively simple, that is, to match the engine with a 48V battery, a 48V starter and generator, and a corresponding control module. With a 48V mild hybrid system, it will be easier to start and stop the vehicle and drive the air conditioning compressor, which can reduce the engine's fuel consumption and emissions at idle speed, and is also conducive to kinetic energy recovery.

7. Cylinder Shutdown Technology

Cylinder deactivation technology is also called variable cylinder technology. For example, a four-cylinder engine can stop all cylinders from working together under low load. At this time, the ECU can control some cylinders to stop injecting fuel and igniting, and enter the deactivation state. Representative examples include GM's 2.0T and Ford's 1.5T engines. However, cylinder deactivation technology also has many difficulties, such as ensuring smoothness after cylinder deactivation, cylinder deactivation time control, and temperature control.

8. Dual circulation technology

When it comes to dual-cycle technology, we need to know the Otto cycle and the Atkinson cycle. "Dual cycle" means switching between the two. The Otto cycle is like a sprinter, with strong explosive power but not fuel-efficient; the Atkinson cycle is like a long-distance runner, although the power is not very strong, but the fuel economy is good. Through variable valve timing technology, the two cycles can be combined to achieve the goal of both fuel saving and sufficient power.

9. Variable Compression Ratio

When it comes to variable compression ratio technology, everyone naturally thinks of Nissan, which has transformed the engine's single-link into a controllable multi-link mechanism, and uses an eccentric shaft to control the multi-link structure to achieve a change in compression ratio from 8:1 to 14:1, making the compression ratio perfectly matched to each speed range, and improving both power and fuel economy. Currently, the representative models equipped with variable compression ratio engines are Teana and QX50.

10. SPCCI Technology

SPCCI stands for "spark controlled compression ignition" technology. It appears on Mazda's SKYACTIV-X engine. The principle is to first ignite a small part of the mixture with a spark plug, causing it to expand and squeeze the rest of the mixture. As the piston moves further, the rest of the mixture is compression ignited. In this way, lean combustion can be achieved, solving the compression ratio problem that has troubled many car companies. It can be said to be a major innovation in the engine industry.