As the core of power transmission, the classification of automobile transmission systems directly affects the power and economy of vehicles. At present, the mainstream types can be divided into four categories according to the structure and drive mode to meet the needs of different models.
The mechanical transmission system is the mainstream configuration of traditional fuel vehicles. It consists of a clutch, a manual transmission, a drive shaft, etc., and transmits power through gear meshing, with a transmission efficiency of more than 95%. Manual transmission models (MT) rely on the driver to shift gears, with a simple structure and low maintenance costs. They are suitable for economical cars and commercial vehicles, and account for more than 40% of the low-priced market.
The hydraulic transmission system replaces the clutch with a torque converter, and is matched with an automatic transmission (AT). It transmits power through hydraulic oil and can achieve smooth shifting. Models such as 6AT and 8AT are widely used in mid-to-high-end fuel vehicles. They can withstand large torque (≥350N・m), are suitable for SUVs and luxury cars, have outstanding comfort, but the transmission efficiency is 5%-8% lower than that of mechanical transmission.
The electric drive transmission system is the core of new energy vehicles, divided into single-motor and dual-motor architectures. The single-motor system directly drives the wheels through a reducer (such as Tesla Model 3), with a transmission efficiency of over 90%; the dual-motor four-wheel drive system (such as BYD DM-i) has motors on the front and rear axles, which can independently control torque, improve acceleration performance by 30% and reduce energy consumption by 15% compared to traditional four-wheel drive.
The hybrid powertrain combines the advantages of fuel and electric drive, and is divided into three types according to the structure: series, parallel, and hybrid. Toyota's THS hybrid system coordinates the engine and motor through a planetary gear set, using electricity at low speeds and oil at high speeds, and its overall fuel consumption is 40% lower than that of fuel vehicles of the same level; the Ideal ONE series system is powered by the engine and driven by the motor, taking into account both endurance and power, and is suitable for family users.
Different transmission systems have different focuses: mechanical transmission focuses on reliability, hydraulic transmission focuses on comfort, electric drive focuses on high efficiency and energy saving, and hybrid power balances endurance and environmental protection. When choosing, it is necessary to consider the purpose of the vehicle model (commuting, off-road, long-distance) and power requirements. Its technological iteration promotes the upgrade of automobiles to efficiency and intelligence.
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