When I was little, I always thought heavy-duty mining trucks were powered by diesel engines, like regular trucks, with clutches and gearboxes. Later, I saw online that these trucks are actually hybrids, with the diesel engine solely responsible for generating electricity, which then drives the vehicle.
At first I didn’t understand why this was necessary, but as I got to know more about cars and machinery, and looked up some information about this type of car, I realized that this type of car can only be powered by a diesel engine and an electric motor, and it is difficult to use direct engine drive.
1.Electric motors are easier to operate than diesel engines
This type of vehicle can haul hundreds of tons at a time. If it were powered directly by a diesel engine, starting would require coordinated accelerator and clutch operation. Starting a multi-ton behemoth on a hill would require daily clutch replacement. Starting with an electric motor is much easier; simply press the accelerator, and even a C1 will successfully start.
Furthermore, clutch control isn’t as precise as with an electric motor. If a diesel engine were used for direct drive, the driver could easily end up in a ditch if they couldn’t properly control the throttle and clutch when reversing, given the weight of the vehicle, which weighs several hundred tons. Electric motors, on the other hand, offer precise control, making even reversing a centimeter easier than with a clutch.
2.High Efficiency of Electric Drive
This type of vehicle is much larger than we imagine. If it were directly driven by a diesel engine, the clutch would likely be as large as a heavy truck wheel, the transmission gears would be at least as large as a car wheel, and the drive shaft would likely be as thick as a bucket. Not to mention the manufacturing complexity, all this equipment would weigh dozens of tons. The truck not only has to pull it, but also has to rotate and rub against it, consuming a considerable amount of power.
Furthermore, clutch control isn’t as precise as with an electric motor. If a diesel engine were used for direct drive, the driver could easily end up in a ditch if they couldn’t properly control the throttle and clutch when reversing, given the weight of the vehicle, which weighs several hundred tons. Electric motors, on the other hand, offer precise control, making even reversing a centimeter easier than with a clutch.
3.Brakes
This type of vehicle weighs hundreds of tons. Traditional mechanical brakes would likely require brake pads all over the vehicle, otherwise they simply wouldn’t be able to withstand the intense friction. Engine braking not only requires a stronger transmission system, but also lacks sufficient power.
Using an electric motor, however, allows the motor to apply reverse torque to slow the car down. During deceleration, the motor becomes a generator, sending the generated current to a large resistor, which is converted into heat and dissipated. It’s said that this type of car uses electric braking at high speeds, and only uses mechanical brakes when the car is about to stop.
I often hear that many diesel trains use a similar drive principle to mining trucks—instead of the diesel engine directly driving the wheels, the diesel engine first generates electricity through a generator, which then uses an electric motor to propel the train forward. I’d like to ask those in the know if this is actually the case.
