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[YesAuto Engine Technology] Recently, while browsing foreign websites, I saw an article discussing “engines will be developed with a single-cylinder 500mL volume”. Let him say that, I can really count many such engines at once. Whether it is a coincidence or a rule, let’s take a look at what this article says. According to the author of this article, German scientists had reached such a conclusion more than ten years ago.

● Those engines developed on the basis of a single-cylinder 500mL

● Reason 1: Good fuel economy

Because of this cylinder volume combined with a long stroke, small bore cylinder structure, the engine achieves the best possible balance of fuel economy and power. German brands such as Mercedes-Benz, BMW, and Volkswagen have all agreed with this conclusion. In order to seek higher fuel efficiency, long-stroke engines with a single-cylinder 500mL displacement are included in their product series, and by adding supercharging and direct injection technologies, The fuel economy of the engine is further improved. Later, Fiat and Jaguar Land Rover also began to produce such engines.

● Reason 2: Good power performance

You may have heard the barrel theory, which means that the evaluation of the quality of things depends on their comprehensive performance. Similarly, the quality of an engine depends on whether its power is balanced. In terms of the engine’s power output characteristics, it depends on what speed it can output the best power. The wider the speed range when peak torque and power are reached, the better its performance. Excellent performance in a small speed range is not acceptable.

This 500mL single-cylinder displacement, small bore, long stroke engine, combined with supercharging technology, can achieve peak torque and peak power in a wide range of speeds. In terms of engine structure alone, the small-bore design shortens the combustion stroke of the flame after ignition, and reduces the combustion of the flame at the edge of the cylinder, thereby improving combustion energy efficiency to a certain extent. In addition, the combustion chamber space of this engine is smaller, which is more conducive to the work of the engine cooling system.

● Reason 3: Cater to emissions tax regulations

In addition, an important factor for more and more car companies to develop such engines is that engines developed on the basis of a single-cylinder displacement of 500 mL can better cater to global displacement tax regulations. Taking China as an example, the consumption tax levied on imported cars is classified as follows according to the displacement:

(China) Consumption Tax on Imported Vehicles According to the Regulation Table of Displacement Level

Displacement 1.0-1.5L 1.5-2.0L 2.0-2.5L 2.5-3.0L 3.0-4L Above 4.0L
Tax rate 3% 5% 9% 12% 15% 40%

If you want to know more about tariffs on imported cars, please click the link below:

● Representative of 500mL single-cylinder engine

So far, the most typical representative for the production of 500mL engines with single-cylinder displacement is undoubtedly BMW. Many of BMW's current and ready-for-sale models have engines designed in this way, including three, four, and six-cylinder gasoline and diesel engines. For example, BMW’s latest 1.5L twin-turbocharged three-cylinder gasoline engine is mounted on the 2015 MINI COOPER. Its cylinder diameter×stroke is 82mm×94.6mm, and it uses direct injection and variable valve timing. And lift technology.

This kind of engine is also more suitable for modular production. For example, 60% of the components of this BMW engine can be used in the three gasoline engines, and 30% to 40% of the components can be shared on the two diesel engines.

Although the future development trend of automobiles is the field of low fuel consumption, low emission hybrid and electric vehicles, the constantly updated and iterative Otto cycle engine still represents an irreplaceable backbone force today, 139 years later.

Edit summary:

Although the conclusions in the article seem quite reasonable, obviously you will refute it by listing many new engines that are not based on 500mL single-cylinder displacement. In fact, let alone the efficiency issue, at least this design is very consistent. The concept of modular development. Imagine that if you use this method for engine research and development, then the power requirements of products with different positioning under the same brand can be met by adding and reducing cylinders, and then by combining supercharging technology and other optimization technologies. Strive for a balance between power and economy. Indeed, this is what BMW does now. (Compiled by Dong Yu / Xia Zhimeng of the car home)