An important indicator for measuring engine performance-High Power

The engine quality mainly depends on the power and economy. That is to say, the engine must have good power, good acceleration, and low fuel consumption. There are many factors that affect the engine power and fuel consumption. The most influential factors include the displacement, compression ratio, and distribution mechanism. However, this is just generic. Compared with the engine, the difference in purpose, design, material and manufacturing process often leads to a significant difference. Some engines with a large displacement may not necessarily have a higher power than those with a smaller displacement. For example, in a displacement comparison, the maximum power of a 2.0-litre engine is 97 KW, the maximum power of B's 2.2-litre engine is only 79 KW. Similarly, some cars share the same displacement, but the output power is different from that of the 2.0-litre engine. Therefore, an indicator is generated, called "high power ".

The engine is an effective indicator based on the crankshaft output power, which indicates the overall engine performance. Effective indicators include effective power, effective torque, and high power. Generally, the power and torque indicators can reflect the advantages and disadvantages of the engine, but they are not. The higher the power and torque, the better the engine. The indicator that truly reflects the engine power is the power emitted by the working volume of each litre of the cylinder, that is, the "high power ". The higher the power represents the utilization rate of the unit cylinder's working volume. The higher the power, the higher the power emitted by the unit cylinder's working volume. Then, when the engine power is certain, the higher the power, the higher the weight utilization rate of the engine, the smaller the engine, and the lower the material.

The high or low power reflects the quality of design and manufacturing of the starter. Because the ascending power (n) is mainly determined by the product of the average effective pressure (P) of the cylinder and the rotation speed (N), that is, n = (p) × (n ). To increase the power, you must increase the cylinder pressure and speed. Therefore, the specific measures to increase the power include:

(1) Improve gas filling. This is the primary condition for a four-stroke engine to increase heat. Because the fuel combustion requires air, the fuel and air are more difficult to charge into the cylinder, so it is necessary to improve the ventilation conditions, reduce the intake resistance and increase the cross-sectional area of the valve passage. Some engines adopt the 4-valve form. When the multi-valve structure is difficult to deploy, it must first meet the needs of the intake valve. Regardless of the valve layout, the number of intake valves is equal to or greater than the number of exhaust valves.
 

(2) increase the speed to increase the charge per unit time. Nowadays, cars generally use high-speed engines with a rotation speed of more than 5 thousand RPM.

(3) Improve the mixture quality and combustion process. The Electronically Controlled Fuel Injection System is used to ensure the optimal mixture quality under all conditions. The mixed air and fuel are moved from the throttle to the nozzle, and the fuel is directly mixed with the inhaled air, in essence, the uniformity of the mixture is improved.

(4) improve the mechanical efficiency of the engine and increase the output of effective functions. Reducing mechanical losses is mainly to reduce friction between parts, it involves machining precision, Surface Processing Quality, lubrication quality, temperature control and accessories reduction. It is pointed out that the structure of the Multi-valve and the two-valve design is the biggest difference, that is, the structure of the Multi-valve distribution is complex, and the valve, catheter, camshaft rocker, and so on are added, some also need to add a camshaft, that is, double-pin camshaft (DOHC), these added devices will inevitably increase mechanical losses. Therefore, some practical manufacturers still adopt a 2-Valve Design on small and medium-sized vehicle engines.

The above four points are interrelated. For example, the higher the engine speed, the more prominent the problem of reducing the charge of each cycle. This requires measures to increase the cross-sectional area of the valve channel, increase the diameter of the intake valve head or use multiple intake valves. However, the use of multiple valve forms will involve Engine Mechanical efficiency issues. There are always contradictions in the world. How do factory engineers adjust the balance point and try to handle all kinds of contradictions as far as possible is reflected in the performance of various engines.