Eaton Char-Lynn Motor – Double-Edged Sword: Turbocharged Motor


     The term turbocharger is not so strange to many people. The domestic car has been applied since 1998, from Audi A6 1.8T, Laobaolai 1.8T, Passat B5 1.8T, and now to Mingrui and Roewe. 550, Roewe 750, MG 7, etc., many domestic joint venture brands and independent brands have widely used turbocharged motor technology.

  Before and after the Shanghai Auto Show in 2009, Volkswagen announced that it will introduce a 1.4T motor that is comparable to naturally aspirated 2.0 motor power. It is equipped with new Bora, LaVida and Sagitar models, which once again triggered widespread public attention on turbo technology. Recently, it was reported that Chery will produce supercharger, which is another manufacturer of pure self-owned brand after entering the turbocharged field after Brilliance. For a time, this method of increasing the displacement without increasing the displacement has been widely sought after. It seems that the development of turbocharged motors has become a trend, which has greatly replaced the trend of naturally aspirated motors. But is it really possible? How do we choose a turbocharged motor model and a naturally aspirated motor model when buying a car? Presumably these problems have plagued many people. Here we don’t show our position first. Let’s take a look at the development of turbocharged motors.

  First of all, a concept is clarified that turbocharging is only one type of supercharged motor. The supercharging technology of an automobile motor can be divided into mechanical supercharging and exhaust turbocharging. Among them, exhaust turbocharging technology is what we often say. Turbocharging is the most widely used due to its higher energy efficiency ratio.

  Turbocharging technology has been used in the car industry for more than 30 years. The biggest advantage of turbocharging is that it can increase the power and torque of the motor, and at the same time, it can also reduce emissions due to more combustion. Since such a good technology, why has it not been able to replace the naturally aspirated motor for so long? In fact, this is due to the limitations of turbocharging technology. This technology has obvious advantages, and the shortcomings are obvious. It can be said that supercharging technology is a double-edged sword.

  Eaton Char-lynn Motor    analyzes the advantages and disadvantages of turbocharged motors, technological advancement and selection principles

  Turbo: a good double-edged sword

  The advantages of turbocharging are obvious, and they can significantly increase power and torque without increasing motor displacement. When a turbocharger is installed in an motor, the maximum output power can be increased by approximately 40% or more compared to the uncharged supercharger. This means that an motor of the same size and weight can be boosted to generate more power, or a small displacement motor can be boosted to produce the same power of a larger displacement motor. In addition, the motor can improve fuel economy and reduce exhaust emissions after using supercharging technology. Relative to the advantages, the disadvantages of the supercharged motor are mainly manifested in the following aspects.

  Manufacturing complexity is high. After the motor adopts exhaust gas turbocharging technology, the maximum burst pressure and average temperature generated during the operation will be greatly improved, so that the mechanical performance and lubrication performance of the motor will be affected. In order to ensure that the supercharged motor can work reliably and durable under the conditions of high mechanical load and thermal load, it is necessary to make necessary changes in the selection of the main thermal parameters of the motor, structural design, materials, and processes, rather than simply It is enough to have a supercharger on the motor. Because this change process is quite difficult to implement, and also needs to consider the matching problem between the supercharger and the motor, it also limits the application of the exhaust turbocharging technology to the motor to some extent. Relatively speaking, when the exhaust turbocharger is operated in conjunction with the diesel motor, the turbine allows a wide range of work, and the high efficiency range is also wide, and fewer problems occur in the cooperative operation, so the exhaust turbocharging technology is applied in the diesel motor. More. After the gasoline motor is pressurized, the temperature and pressure of the compressed gas in the cylinder and the combustion gas are increased, the heat load of the heated parts of the combustion chamber is increased, and knocking is easily generated. This is the main reason why the supercharging technology has not been widely used in gasoline motors so far.

  Accelerated hysteresis, and the speed is nonlinear. The turbocharging technology drives the turbine by the exhaust gas from the motor, and then the turbine drives the compressor impeller on the same shaft to press more air into the cylinder. Due to the inertia of the impeller, the response to sudden changes in the throttle is slow, and even after the improved reaction time exceeds 1 second, the motor delay is increased or the output power is reduced. For a car that suddenly accelerates or overtakes, it will feel a bit uncomfortable in an instant. In addition, there is a problem of accelerating nonlinearity in the turbocharged motor, that is, at low speed, since the kinetic energy of the exhaust gas is small, the turbocharger does not start at this time, and the turbocharger starts after reaching a certain speed, but the turbocharger starts. Once the supercharging starts, the power of the motor will increase greatly. The sudden increase of the power will make the acceleration of the whole vehicle have a jumping process. This nonlinear acceleration makes the driver and passenger feel uncomfortable.

  High maintenance costs. The turbocharger is installed on the intake and exhaust manifold of the motor. Under the conditions of high temperature, high pressure and high speed operation, the working environment is very harsh and the working requirements are more demanding. Therefore, in addition to the materials and processing technology for manufacturing, At very high requirements, lubrication of the turbocharger shaft is also very difficult. The cost of solving this problem is to increase costs. In addition, since the turbocharger will run for a period of time due to inertia after the flameout, but the motor is stopped due to lack of lubrication, even if the cooling device is added, this ill disease cannot be eradicated, so if it is used improperly, it is easy to cause The turbocharger is damaged, the price of the turbocharger is very high, the domestic minimum is about 4,000 yuan, and the imported one is between 20,000 yuan, which increases the maintenance cost.

  The supercharged mode encounters a speed bottleneck. The supercharger is driven by the motor crankshaft through the pulley, so it is to sacrifice some of the power to achieve greater power boost, but due to the limited motor speed, the supercharger speed is far less than the exhaust turbocharged The speed of the device is therefore inefficient. The supercharger is only suitable for use at low speeds. At high speeds, the booster efficiency is low, so how to combine the two superchargers is perfect. This dual-charged motor has been applied to Volkswagen’s TSI motor and the results are very good.

  The key to turbocharged promotion: technological advancement

  Today’s turbochargers are unmatched in terms of overall size and performance, and today’s turbochargers are becoming more compact and more efficient. From this we can easily find that if we want to promote turbo technology, technological progress is the only way out. Since the introduction of the turbocharger, it has been technically modified, such as improving machining accuracy, minimizing the gap between the turbine and the inner wall of the turbine, in order to improve the energy efficiency of the exhaust gas; using new material ceramics, using ceramics with high heat resistance The advantages of high rigidity and light weight make the turbocharger more compact, less bulky, and reduce the “lag response” time of the turbine.

  Turbocharged model purchase principle: see the car

  Whether you choose to buy a turbocharged car depends on your car environment. If you often drive in a city with heavy traffic, you don’t have to buy a turbocharged car. The reason mentioned earlier, the turbocharger does not work at low speeds, usually only above 2000 rpm. In urban congested roads, there are few turbocharged jobs, which wastes and shortens the life of the turbocharger.

  Second, we have to look at the individual driving needs. If you prefer high-speed driving, it is best to choose a turbocharged motor, because after the booster is started, the power and torque of the motor are greatly improved, and it is easy to enjoy the feeling of driving when driving at high speed.