Why is the engine not in the trunk?

For cars, there are two places on the body to place an engine. One is that the engine should be in place – “front box”, and the other is a trunk that has been treated as a storage space. Then why is most of the models now choose to put the engine in the “front box” instead of the trunk?

The front of the front of 5 meters

Early car The rich exclusive tools, with a 5-meter-opening bus, do not worry about the interior of the car. As the automotive manufacturing technology is mature, in the 1930s and 1950s, the automobile gradually started the process of civilianization, tried to spread down to thousands of households in the form of microcons.

However, it is limited to that the steering section technique is not mature enough, so the pre-pre-pre-prior pre-predefiglement form that is most suitable for home is not implemented. If you follow the front-drive form of the exclusive era of the rich era, there is a huge drum in the car, which will make the microcarnote a narrow car space to be more stretched. In order to solve the problem of the dynamic system invaded the vehicle space, the automotive engineer decided to develop the model after the post-driven model, by using the second row of seats, and the trunk space is placed, the passenger space in the microconius Integrity.

The big name is famous, from Ferdan German Middot; Porsche in the 1930s, the world’s first rear after the world’s first post-drive microcar . It realizes the 4-meter body length to achieve four adults and have a larger inner space. Subsequently, Fiat 500 listed in 1957 also provided four comfortable seats only in the rear rear-drive structure, only less than 3 meters of the body length.

BMW 700

The trend of the rearward rear drive has continued until the 1960s, and BMW 700, Hilman IMP was also born during the period. Classic model. but,With the overcoming of the 10,000-day technology, the world’s first model of the world was born in 1959, it is the MINI we are familiar with. And its birth, also opened the sequence of the rear afterwards.

[123 ] In terms of space, if it is the back rear drive, the head will take responsibility for the storage space. However, since the front wheel needs to be responsible for the steering, the front spare box must leave space for the maximum corner of the front wheel, eventually leading to space stenosis. This is undoubtedly a big disadvantage than the front prior score that can provide a pre-pre-spatial trunk space that is almost the same as the trunk space.

Chevrolet Corvair

With people’s pursuit, the volume is getting more and more The large engine cannot be rearwarded below the rear seat, so the engine and gearbox can only be placed behind the rear axle. As a result, the trunk of the vehicle must be extended to the length of the power assembly that can accommodate the engine and gearbox, and the final vehicle body ratio will be removed after the back of the 1960s. Corvair (above The same, it becomes very strange, even it is difficult to distinguish it is a head, which is a car tail.

If it is not to follow the rear rear drive technology route, then To ensure the beauty of the body’s gesture, and the rationality of the space layout, the ultimate form of its ultimate form will definitely use the horizontal opposite engine with absolute advantage in height. However, due to the horizontal opposing engine, it is comparable to the manufacturing cost of the V-type engine, and because the horizontal opposing engine is too wide, the problem is uncomfortable, and there is a level of comparative characteristics, even the natural and easy to explosive. Quality, so if you adhere to the back, and die, you can easily make the entire brand nowColumn 4 cylinders are pulled in the mainstream market.

Highly manufacturing costs and narrow nacelle spaces will increase significantly Reserved maintenance costs. It is like replacing spark plugs, air-filtration, this general person can work, in the back engine, because there is no space in the cabin, resulting in the entire engine to be replaced. This obviously increases daily maintenance, maintenance, which has greatly improved the cost of car owners.

Further, since the chamber itself of the post engine is extremely compact, coupled with the rear lack of sufficient resistance structure and the relationship of the heat sink. So in our common rear-end accidents, the latter engine will be very large. Therefore, the insurance cost of the rear model will also be higher than the pre-model type, further increase the cost of use in the future.

For the car, since the first to air is in contact with air The head, so the front engine can always be in direct contact with the most “fresh” air to take heat away. But the back engine wants to achieve the same heat dissipation. For example, Porsche 911 is through a long line, and the engine heat radiator is introduced to the head to exchange efficient heat dissipation. Such a design is not only costly, low efficiency, and the space of the front box will be further compressed and become more narrow.

If the high-performance version 911 GT3 R, 911 GT2 opens in the side of the body to help the engine heat dissipation, the car is It can only be designed with two doors, otherwise the length of the car will be very exaggerated. Of course, opening holes above the roof can also be dissipated to the engine, but this form of heat dissipation efficiency is not high, only the small horsepower engine with a small amount of heat. Therefore, if you want to completely solve the heat dissipation problem of the post-engine, it is obviously more troublesome than the front engine.

The last disadvantage of the rear rear drive is the life of the old life Anti-normal operation problem. For the front rear drive and the middle, when the rear wheel breaks through the grip, because the tail will not excessively heavy, the driver can restore the vehicle only by the way of rejecting the rear, and the direction of the direction can be restored to the vehicle. Normal driving status.

The rear rear drive is not the case. Since most weight is compressed in the end of the car, it will produce huge inertia when the rear model is tail. At this time, if you follow the common sense, completely loosen the throttle, the car is taken away by the imperial inertia, which will eventually be completely out of control. Therefore, when the latter driver is out of control, the correct life will be, keep a small throttle and counter-direction, after the rear wheel grabs a slight recovery, this small throttle brings forward The force can pull back the tail. However, this out-of-control has continued to operate the oil, which is obviously anti-human, so the rear-rear-drive 911 has been carrying the “Widow Manufacturer” before the ESP is born.

According to the above argument, the rear drilling type is born Many defects. So why did the Porsche have been in the form of after the lapse of the leader of the sports car?

As is well known, Porsche 911 is a relatively balanced sports car, both Curve control or acceleration performance, almost all the leaders of the same level. Similarly, the 911 Carrera S achieved only 3.4 seconds of exaggerated acceleration capabilities with rear wheel drive and 450 horsepower, and the acceleration process is quite stable, and there is no other rear driver, and the restless car tail gesture. And all the above, it isThe advantages of the rear post drive layout.

Everyone knows that during the acceleration process, because the weight movement is moved backwards, the rear wheel will bear more weight, grip Will increase. Therefore, in the case where the horsepower is the same and the transmission efficiency is consistent, the rear drive often has a faster acceleration time.

When the post-driven Porsche 911, since the engine itself is behind the rear axle, the pressure between the rear wheel and the ground is also It is much higher than other after another. Plus the back shift of the body weight when acceleration, 911 can release all the horsepower to the ground with the rear wheel, which is also a quick and fast cheat of Porsche 911 accelerated. And after the 911-driven system with such a metamorphosis, 650 horsepower 911 Turbo S has a 2.6 second break of terror acceleration.

Because most weight is pressed against the rear of the vehicle, Compared to the front or hidden engine model, the front wheel of the rear driver has a congenital disadvantage. This will result in the rear rear driver type in the insertion and bending stage, if the traditional manner is used, it is the toner door in the face of the short curve, and the operation of the oil in the face of the longer curve The way, the vehicle will show a clear pose posture (the correct method is to carry the brake into the head, thereby increasing the front wheel grip of the post-drive model). So obvious, the push head is definitely more stable than the tail. When the bend, it is benefited from the rear wheel with a greater grip relationship. After the rear, the driver will have higher degreasing when the bend is accelerated, and it is not easy to be bent because the throttle is caused. Tail.

However, it is premise that the rear rear drive is not easily out of control, that is, the driver must have superb driving techniques. Because as long as the driver is not controlled, it is not good to control. Trail Braking.The brake strength of the bend causes the brakes to be large, and the heavy car tail of the 911 will be due to the lack of land for the rear wheel, and there is almost unrealtened severe tail. Therefore, although the rear driver is orientation, it will instantly become a tail as long as the operation is improper operation, and you are in danger.

Put rod suspension

Since the engine is not in front, the rear engine The model will have more headspace space available. Therefore, the rear model has a larger space to design your own front suspension form. For example, the double-binary arm that occupies a lateral space can be easily arranged on the front wheel of the rear driver. It can even use the curve performance directly, but extremely footprint (pull) rod suspension. Only, the better the suspension form means that the smaller the front of the storage space, so the post-drive form will be more suitable for sports cars with high storage space requirements, rather than ordinary buy vegetables.

above explains the post becomes “non-mainstream” The reason, it seems that the front engine occupies the mainstream is already a thing that is in the case. But in fact, in the upcoming new energy era, instead of the motor’s motor will no longer be more changing.

The two-motor assembly of the integrated solid gearbox

This is mainly because of the motor responsible for driving the electric vehicle, both in size or weight. It is much smaller than the internal combustion engine. Generally, the weight of the normal car internal combustion engine is about 120kg, while Tesla’s electric motor is only 35kg. The same is true, and the size of a general four-cylinder internal combustion engine also has 0.144 m ⊃3; (40x60x60cm cube), and the Tesla motor is only 0.01m ⊃ 3; (23x23cm cylinder). Through the calculation, it can be obtained, one ordinary four-cylinder engine is 14.4 times larger than the single motor, which is 3.42 times.

More critical is that due to the electric vehicle, there is no multi-gear gearbox on the internal combustion engine model, usually only two gears can reduce the gearbox. Speed ​​torsion function. Therefore, the driving device of the electric vehicle should be significantly smaller than the internal combustion engine whether it is volume or weight. At this time, considering that the total weight of the total weight of the electric vehicle is usually installed under the vehicle passenger cabin, so for future electric vehicles, the position installed in the motor does not affect the vehicle manipulation characteristics.

It is also because of such power layout forms, as well as “engine”, so the pure electric model is well design. In the case of it, it is possible to have two storage spaces in the front box and the trunk, and it is also possible to reach 50:50 before and after. In addition, the electric vehicle four-wheel drive system does not require a central transmission axis, so it’s naturally there will be a “central gate” of the fuel four-wheel drive. In the end, it is also more practical, and it is also possible to enjoy ultra-low vehicle gravity and the driving experience brought by neutral vehicle control.

Actually, the evolution of the car is like the evolution of human beings, is an environment The result of the selection. For humans, cruel nature is the filter tool for genes. For goods for the tool attributes of the car, consumers’ demand for large spaces, and the harsh selling price, they directly determine the development path of the car. That is under this elimination mechanism, the rear engine model with high cost and small space is ultimately the choice of the niche, that is, a thing that is normal.