Comparative Analysis of Cast Iron and All Aluminum Engines

The automobile industry has developed rapidly in the past two years in China, and the engine is understood the most. Now, the engine is mainly divided into two types: cast iron cylinder engine and aluminum engine. Both engines have their own advantages. The specific choices must be selected according to their own needs.

First of all, the weight of aluminum is lighter than that of cast iron in terms of quality, and the aluminum cylinder is much lighter under the premise of meeting the strength requirements. The light engine can exert a positive influence on the weight distribution of the entire vehicle, and the overall vehicle quality is also lighter. Therefore, the aluminum cylinder is dominant at this point. However, aluminum has a low specific gravity, and its structural strength per unit volume of aluminum is smaller than that of cast iron, so the aluminum cylinder is usually larger in volume. Removing the cooling water passage actually makes the cylinder wall quite thin. In this way, the entire engine is compact and small. Aluminum cylinders are more difficult to achieve this effect.

Aluminum easily reacts chemically with the water produced during combustion and is not as corrosion resistant as a cast iron cylinder, especially for booster engines with higher temperature and pressure. Therefore, when the automobile engine volume requirement is small, it is very difficult to use the aluminum cylinder body to achieve the strength of the cast iron cylinder body. Therefore, most high-pressure engines use cast iron cylinders. Aluminum conducts heat faster, so the cooling performance is good, can help the engine to reduce the probability of abnormal combustion, the same compression ratio, the aluminum cylinder engine can use lower-grade gasoline than the cast iron engine.

In modern engines, aluminum alloys are mostly used as materials for pistons in order to reduce the inertia of reciprocating components and increase speed and response speed. If the cylinder wall is also aluminum. The friction coefficient between aluminum and aluminum is relatively large, so that the performance of the engine is greatly affected. Cast iron cylinder engines have no such problem.

The cast iron production line in the engine casting has a large area, which has large environmental pollution and complicated processing technology. The production characteristics of cast aluminum cylinders are exactly the opposite. From the perspective of market competition, cast aluminum cylinders have certain advantages. Because of the advantages of cast aluminum cylinders, for example, Japan has mainly developed engines for cast aluminum cylinders. However, one of the reasons why Toyota's engine is made in China is a cast iron engine. One of the reasons is that China's raw materials are not as scarce as Japan. From the current situation, the price of aluminum in the market is not low, which weakens the advantages of the aluminum cylinder engine in production and processing. The heat load capacity of the cast iron cylinder is stronger, and the potential for cast iron is greater in terms of engine power. For example, the output power of a 1.3-liter displacement cast iron engine can exceed 90 kW, while the output power of a cast aluminum engine can only reach 60 kW. It is understood that the 1.5-liter displacement cast iron engine can be turbocharged and other technologies. The power requirements of engines with a displacement of 2.1 liters or more are achieved, while cast aluminum cylinder engines are difficult to meet this requirement.