When the people from Xiang & Tan Motor Factory were shocked by Lin Zheng's wealth, Lin Zheng was also depressed: He needed to have a detailed understanding of electric drive technology.

Since we want to understand electric drive technology, we have to talk to Andre.

"The development of electric drive technology has actually been many years. The earliest ones were urban rail trams, which were considered early electric drive technology. However, if we talk about the early power drive technology of mine vehicles, it would have to be traced back to the early stage of World War II. Well, it was the first time that Italy used electric trucks to transport concrete when it was building the Valtrina Hydropower Station in 1938. At that time, there were 16 three-axle trucks and 4 two-axle tractors on the construction site, but the truck capacity was available.

The power is still not good. Considering the large torque output characteristics of the motor, the construction party converted the 20 trucks into electric drives: a long collector pole is installed on the top of the cab and a 650-volt DC overhead line network is used to provide power to the vehicle. The total length of the line reaches 80 kilometers. In essence, it is similar to the current urban tram and trolleybus. This is considered the earliest mining truck. Of course, to be more precise, it should be said to be the prototype of an electric-driven mine truck."

In 1938? This time was really beyond Lin Zheng’s expectations: Is it so early?

Andre is worthy of being a specialist in electric drive technology, and he is well aware of the development of electric drive technology of mine vehicles. "However, the prototype of the electric drive mine vehicle that is widely recognized by everyone was in the United States in 1939. At that time, the United States International Salt Industry Corporation built an underground mine in Michigan, but it was impossible to enter the mine due to overhead wires. They installed a batch of Ukurid trucks with a load of 20 short tons on a battery, installed the DC motor directly on the differential, and converted it into an electric drive truck. These vehicles were finally successfully used for more than 20 years. These trucks were considered electric drive trucks in the true sense - they were finally no longer limited to overhead cables and could drive freely."

"I understand," Lin Zheng, who had not had time to talk to Andre, finally nodded suddenly, but with Andre's explanation, a new question came again, "Andre. I just want to know that since the power drive technology has been used on mine vehicles for so long, why are there no power drives used on passenger cars and commercial vehicles, and commercial passenger cars?"

Yes. This question is also one of the most puzzled questions since he learned that mine vehicles had already started to use electric drive technology: Since mine vehicles have started to use electric drive technology so early, why hasn't electricity been used as driving power on passenger cars, commercial vehicles and commercial passenger cars?

Well, trams and trolley cars that use overhead cables do not count.

"This involves another issue with the motor, the power density of the motor."

"Power density?" Lin Zheng said in surprise: He has also seen a lot of them during this period.

"Well, also called the power-to-weight ratio. It is a motor, and the maximum power it can emit for each kilogram of its own weight." Andrei explained to Lin Zheng, "This is a relatively remote professional word in motor science."

After understanding, Lin Zheng nodded repeatedly. For example, a motor weighs 20 kilograms and has a power of 2.5 kilowatts, then the power-to-weight ratio. The comprehensive kilometer density of a lake is 0.125. The power density of the motor is to some extent the same as the power of the internal combustion engine. The motor is the maximum kilowatts of power per kilogram. The power of the internal combustion engine is the maximum power of the displacement per liter... Of course, the internal combustion engine also involves a problem of the engine's self-weight. But it is not the main factor affecting the power of the internal combustion engine. The biggest factor affecting the power of the internal combustion engine is the exhaust volume.

"This is the least. If you can achieve a power-to-weight ratio of more than 3, it would be the best. If you can reach 4, it would be ideal," Andrey deserves to have been working on a motor for a lifetime. He already understood the boss's meaning. He nodded immediately after hearing this. "Andrian immediately floated up and down at a ratio of 1:2. He felt that floating up and down was a relatively safe situation, but this requires the motor speed to reach a very high level. For DC permanent magnet motors, the speed must be more than 11,000, and even an AC excitation motor, the speed must be above 8,500 revolutions."

1:2? That is, the output power of 100 kilowatts requires approximately 200 Nm of torque? Well, compared to the exaggerated power and torque output ratio of the mine car motor of more than 1:10 that I learned some time ago, this ratio is really suitable for passenger cars.

In order to meet the requirements of automobile use, the ratio of power and torque of the gasoline engine is even more exaggerated, almost 1:1... Although the different considerations of each company have caused this ratio to fluctuate slightly, it only floats up and down between 1:1 and 1:1.5.

"Since that's the case..."

Lin Zheng raised his head and looked at Andre, "Andre, the company is preparing to launch the electric drive technology of passenger cars. Well, the first thing to launch is the 'gasoline-electric' hybrid drive technology, which is similar to the theory of the concept car called 'pris' exhibited by Toyota at the Tokyo Motor Show. However, the slightly different thing is that the one we are going to do is to be more advanced, and can directly connect to the mains power for charging. What do you think?"

"Toyota Prius?" Andre frowned and thought for a while, but finally he didn't remember what the Toyota Prius was. He could only smile bitterly, "Boss, I'm sorry, what kind of hybrid driver concept is this Toyota Prius?"

It is understandable that Andre didn't understand Prius. Although Prius first appeared at the Tokyo Auto Show in October 1993, Belarus was in dire straits at that time. Who had the time to pay attention to such a hybrid car that was thousands of miles away?... What kind of car is not a car? Serious ones are to fill my stomach first.

Although Andre had just gone to the United States at that time, he was thinking about gaining a foothold in the United States when he had just gone to the United States. Naturally, he could not pay attention to this little thing... His business and work were mine vehicles with a load of hundreds of tons. Prius was basically incompatible with his work.
Chapter completed!