Effect of Exhaust Gas Turbocharger on Engine Performance

2019-06-25 09:10:17

The greatest advantage of turbocharger is that it can greatly increase the power and torque of engine without increasing engine displacement. Generally speaking, the power and torque of engine with turbocharger will increase by 20%~30%.

 

The disadvantage of turbocharger is lag, that is, because the inertia of impeller reacts slowly to the sudden change of throttle, the engine delay increases or decreases the output power, which is a little weak for the car to suddenly accelerate or overtake. Previously, turbochargers were mostly used in diesel engines, but now some gasoline engines also use turbochargers. Because the combustion mode of gasoline and diesel is different, the engine using turbocharger is different from that of diesel engine. It enters the cylinder not air, but the mixture of gasoline and air. It is easy to deflagrate if the pressure is too high. Therefore, the installation of turbocharger must avoid deflagration, which involves two related issues, one is high temperature control, the other is ignition time control. After forced supercharging, the temperature and pressure of gasoline engine during compression and combustion will increase, and the deflagration tendency will increase.

 

In addition, the exhaust temperature of gasoline engine is higher than that of diesel engine, and it is inappropriate to increase the overlap angle of valve (the opening time of intake and exhaust valves at the same time) to enhance the cooling of exhaust, and reduce the compression ratio will cause insufficient combustion. Moreover, the speed of the gasoline engine is higher than that of the diesel engine, and the air flow rate varies greatly, which easily causes the reaction lag of the turbocharger. In view of a series of problems arising from the use of turbochargers in gasoline engines, engineers have made specific improvements one by one so that gasoline engines can also use exhaust turbochargers.

 

 The air sucked by the turbocharger of the intercooler is compressed at a higher temperature, and the friction with the intake pipe wall will further increase when it flows, which not only affects the charging efficiency, but also prone to deflagration. Therefore, it is necessary to install the equipment to reduce the temperature of the intake air, which is the intercooler. It is installed between the outlet of the turbocharger and the intake pipe to cool the air entering the cylinder. Intermediate coolers are like radiators. They are cooled by wind or water. The heat of air is dissipated into the atmosphere through L cooling. According to the test, the good performance of the intercooler can not only keep the compression ratio of the engine at a certain value without deflagration, but also reduce the temperature to improve the intake pressure and further improve the effective power of the engine. Because the speed range of gasoline engine is wide and the air flow rate varies greatly, the compressed impeller of turbocharger is a complex three-dimensional curved ultra-thin-walled impeller blade, which generally has 12-30 blades arranged in a radial curve. The thickness of the blade is less than 0.5 mm.

 

The compressed impeller of turbocharger is made by special casting method with aluminum. The shape of blade directly affects the performance of Turbocharged engine. The more reasonable the shape and angle of the impeller, the lighter the mass, the more sensitive the impeller is to start, and the less the "reaction lag" of the inherent defect of the turbocharger is. In addition to lowering the temperature to reduce the possibility of deflagration, the deflagration sensor is also used. Its function is that when deflagration occurs, the sensor feels abnormal vibration and immediately feeds back the information to the engine ECU (electronic control unit) control system, which delays the ignition timing slightly and restores the normal ignition timing when deflagration does not occur. Because the speed of car gasoline engine is higher than that of diesel engine, the air flow speed is faster and the range of variation is larger, so its turbocharger has higher requirements. Electronic injection system has been widely used in modern car engines. With the cooperation of electronic control technology and new materials, the application of turbocharger in gasoline engines will become more and more popular.

WUXI SHENGYI TURBO is a professional enterprise producing turbocharger and turbo repair partshas more than 300 turbocharger models for vehicles application as Garrett, Hitachi, Toyota, Mitsubishi, Benz, BMW, Audi, Ford, Jeep, Dongfeng .etc. Our turbochargers offer direct replacements to OEM models, also offer customized solutions to our customers. We adopt vanguard technology positively from home and abroad, and have established the long-term technical cooperation with many well-known enterprises. We have passed ISO9001:2000 in September, 2004. Now we own the floor space 5800 square meters. There are more than 50 workers including more than 10 technical staff who has the senior or intermediate title and more than 30 first-line workers who have rich experience in turbocharger. For more information please contact us [email protected]