The traditional fuel engine has low thermal efficiency.

The characteristics of internal combustion engine determine that it is difficult to make a big breakthrough in thermal efficiency.

What is thermal efficiency? I don't think it needs further explanation. To put it bluntly, it is the ratio of mechanical energy obtained to heat paid. Some media habitually define 40% thermal efficiency as 10L fuel consumption, and only 4L actually does work. ?

In this way, it can tell Xiao Bai simply and rudely, but it is actually wrong. After all, the thermal efficiency is the highest at present, and the engine working condition cannot always be the highest range.

To tell the truth, the engine alone, even Toyota's high thermal efficiency engine, is more wasteful than expected.

Even dare not count, the waste of the engine has seriously exceeded the standard. If you count the waste of power transmission paths such as gearbox, transmission shaft and wheels, a car with fuel consumption 10L really needs to be converted into the fuel consumption of driving vehicles, and you may not be able to bear to look directly at it.

Every link in the transmission will waste power, especially the rigid connection structure, which will waste more.

The connection between the parts of the car is very hard and it runs at a high speed. Taking the internal structure as an example, high-speed operation will inevitably produce friction, and energy will be converted into temperature. If the internal working temperature is high, it needs to be cooled down.

How to cool down? Why does the dual clutch gearbox always have problems when the oil is cooled? Strictly speaking, it is a dry dual clutch gearbox.

Dry dual clutch gearbox seeks higher transmission efficiency. Compared with wet dual-clutch gearbox, it is not oil-cooled, and long-term high temperature leads to component failure.

The key to not using wet dual clutch before is low transmission efficiency.

But now it is a wet dual-clutch gearbox. Although the efficiency is low, the reliability is improved. But it is undeniable that the engine will convert less mechanical energy.

The front drive is more efficient than the rear drive because the front drive has no transmission shaft. What if? It's rear-wheel drive. Is there any mechanical energy? There's another layer of waste.

These forces are transmitted from the transmission shaft to the wheels, and the friction between the wheels and the ground will consume some energy.

That's it. I dare not even calculate the wind resistance.

In fact, a car with fuel consumption 10L may have less than 20% energy to really push the vehicle forward. I really can't help it. The thermal efficiency of traditional internal combustion engine is too low, and a lot of energy will be wasted only in the engine link.

At present, the thermal efficiency of mainstream engines is lower than 40, and car companies are still promoting "maximum and highest thermal efficiency". However, the thermal efficiency of the engine is the highest when it is started, and the thermal efficiency at idle speed is completely different from that at 1500 rpm, and even different at different engine temperatures and speeds.

Why to ban the sale of fuel vehicles is actually very simple, mainly because fuel vehicles are too wasteful.

Of course, new energy is a big waste, but it is really good that new energy does not burn oil. Electricity is not necessarily obtained by burning coal. There are many ways to obtain electricity, such as wind energy, hydropower and solar energy, and it is not necessary to rely on thermal power to generate electricity.

Either the tanker can't work, or the structural problems are really difficult to overcome in the short term.

Take PDK gearbox with very high transmission efficiency as an example. Porsche 9 1 1 To achieve an acceleration of 3-4 seconds, the fuel consumption has to reach 10L, and there is a lot of energy waste in each link.

Of course, new energy sources are also wasted, but the waste is not as big as that of internal combustion engines. The most important thing is to waste electricity, which can be regenerated, and the oil regeneration time is too long.

By the way, electricity is not polluted.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.