Heavy Truck: Why Does the Heavy Truck Start in 12 Gears

　　Recently, many truck drivers may find that more and more light trucks are equipped with 8-speed transmission, which is called a small 8-gear. Is 6-gear not enough? Why are there 12 or more gears for heavy trucks? Today we will talk about why there are so many gears for heavy trucks?

　▎The maximum torque range is too short due to the characteristics of the diesel engine

　　Compared with gasoline engines of the same level, diesel engines have obvious advantages in torque. They have higher thermal efficiency, and more durable construction, so they have become the first choice for commercial vehicles, tanks and ships. However, the maximum speed and maximum torque range of diesel engines are not as good as those of gasoline engines.

　　Taking trucks as an example, whether it is Mercedes-Benz or Volvo, whether it is Cummins, Weichai, or Xichai, the maximum torque range of almost all diesel engines is very small.

　　For example, Dongkang Z14NS6B520 engine, the book parameter of it is 520 horsepower and 2500 Nm, and the maximum torque range is 1000-1500 rpm;

　　Volvo D16G750 engine has 750 horsepower and 3550 Nm of torque, and the maximum torque range is 1050-1400 rpm.

　　On the passenger truck, BMW B58B30C engine has a 3.0T displacement with 340 horsepower and 450 Nm of torque, but the maximum torque range can last from 1500 rpm to 5200 rpm.

　▎If the speed is not enough, increase the gears

　　With such a small torque speed range, in order to exertthe truck's best power performance within the legal speed limit range, it must be equipped with more gears.The more gears, the better the engine can output at different speeds and under different road conditions. This is also the reason why light trucks start to use small 8-gear.

　　Looking at the passenger truckin turn, from the previous 4AT to the current 8AT, 9AT and even 10AT, there are more and more gears, and the reason is the sameas above.

　▎The more gears, the wider the gear ratio, the more fuel-efficient

　　Any internal combustion engine has its own optimum operating conditions. In order to highlight the fuel-saving performance of the product, the manufacturer will try to make the engine work in the economical speed range as much as possible. For example, when starting, overtaking, and going uphill, choose different low-speed gears according to different road conditions, whileat high-speed stages, choose overdriveor direct driveaccording to the combination of tail gear ratio and rear axle speed ratio as much as possible.

　▎Multi-gear design can fully takethe ride comfortof truck into full consideration

　　The engineof a truck has high power and torque, but the speed range is small. If the transmission gear is too small, it will cause a large impact when the truck is shifting, which will increase the burden and wear of the clutch. Moregear ratios, smoother shifting. But at the same time, the disadvantage is that it requires frequent shifting at different speeds.

　▎Why do many drivers change gearsout of ordereven if the truck still doesn't drive smoothly?

　　There are many gears, which means that from starting to cruising, the driver needs to step on the clutch and engage the gear many times. For trucks that are in the climbing stage or heavy-duty, there is basically no chance for driversto change gearsout of order.

　　However, for some trucks that are not particularly heavy, the demand for power is not large, and many drivers are willing to change gears out of order. In this way, the 16-gear truck can be hung in 8 gears, and it can be hung in the rear gear. The driver's right hand and left foot can save some energy.

　▎The era of AMT is the era of less mistakes

　　The times are progressing, and the manual transmissions that have been used for decades will gradually be replaced by automatic transmissions. It is true that the current automatic transmission is slightly more expensive, but the automatic transmission that is easier, more fuel-efficient, more durable, and more suitable for China VI does have incomparable advantages. Take the AMT transmission, which is currently the most widely used in trucks.

　▎Advantages of automatic transmission vehicles

　　1. Save worry and effort

　　No left foot clutch, no right hand shift. According to the research of Jianghuai Automobile Group, urban logistics vehicles need to shift gears 10-13 times per kilometer. According to the daily mileage of 100 kilometers of urban distribution vehicles, drivers need to shift gears about 1,300 times. Automatic transmission vehiclescan greatly reduce the labor intensity of drivers.

　　2. Avoid mistakes

　　Novice drivers and bad driving habits have a great impact on the life of the clutch, which may lead to the early scrapping of the clutch, or even vehicle breakdown. The automatic transmission vehicle can avoid misoperation, prolong the service life of the vehicle, and reduce the requirements for the driver.

　　3. More environmentally friendly

　　The exhaust gas treatment of Euro 6 vehicles has certain requirements on the operation of the engine. In order to save fuel, some drivers drive at low speed for a long time, and the working pressure of the aftertreatment equipment is huge. Automatic transmission vehicles can perfectly adapt to engine conditions and improve the working efficiency and effectiveness of aftertreatment equipment.

　　4. Safer

　　Vehicles with manual transmission on downhill sections require the driver to have a wealth of driving experience to operate the auxiliary brake. The driving computer of automatic transmission vehicles can control the engine to perform auxiliary braking according to the slope and speed, so as to brake with the best efficiency and improve the driving safety.

　　● Afterwords

　　In conclusion, the more gears, the better the truck's power, fuel economy, and shifting smoothness. However, it doesn't apply in any situations. Too many gears will lead to frequent shifting, resulting in power interruption and increasing the difficulty of the driver's operation. Therefore, there is no best option, only the most suitable option. More options are at  https://trucksglobal.com/product/