Glossary of vehicle configuration (2): driving configuration

●Front Axle/rear axle/Central Differential Lock

These three configurations are related to the differential lock. Because the principles involved are the same, they are combined to introduce them. In order to better understand the concept of the differential lock, first, let's take a look at what a differential is and its role and drawbacks, because in simple terms, a differential lock is a device used to lock the differential.

◆Differential

The car differential is the main component driving the car. Its function is to transfer power to both sides of the Half Axis, while allowing the two sides of the Half Axis to rotate at different speeds, to meet the needs of both sides of the wheel as far as possible in the form of a pure rolling distance driving, reduce the friction between tires and the ground.

Differential Effect

When a car turns, the rail line of the wheel is an arc. If the car turns to the left, the center of the arc is on the left. In the same time, the arc of the Right wheel is longer than that of the left wheel, to balance this difference, we need to slow down the left wheel and speed up the right wheel to compensate for the difference in distance with different rotational speed.

For full-time driving vehicles, the vehicle is equipped with three delimiters, and the four wheels can be rotated at different speeds, and different torque distribution is automatically obtained according to their respective ground adhesion, ensure good driving power for vehicles.

Disadvantages of differential

Now there is a problem: If one side of the drive wheel loses grip, Why cannot the vehicle move forward? That's because when one side of the wheel loses its grip on the ground, the opposite side of the wheel has a resistance of 0, and the opposite side of the wheel has a great resistance compared to the side that loses its grip on the ground, while following the revolution of the housing, the planetary gear in the differential will rotate wildly, and the power will be continuously transferred to the side of the wheel that has lost its grasp of the ground. The car will only stay in the same place.

How can this problem be solved? The following is our leading role, and the differential lock solves this problem:

◆Differential Lock

The difference lock is used to lock the differential shell and the half shaft into one when a drive wheel slide, so that the differential function is lost, and all the torque can be transferred to the other side of the drive wheel.

The Differential Lock solves the power transmission problem that occurs when the vehicle's wheels slide on one side, that is, the lock differential, so that the differential does not work, and the drive wheels on both sides of the left and right can get the same torque.

So according to the position, a good four-wheel drive should have three differential locks, that is, the Central differential locks, the front axle differential locks and the rear axle differential locks.

The central differential lock controls the Torque Distribution of the front and rear wheels, while the front axle differential lock controls the Torque Distribution of the left and right sides of the front wheels. The same applies to the rear wheels.

Electronic Differential Lock

The short name is eds, also known as EDL. It is an extension function of ABS, used to identify whether the vehicle's wheels lose the ground friction, and thus control the vehicle's acceleration and skid. The working principle of EDS is easy to understand. During automobile acceleration, when the electronic control unit determines a drive wheel skid Based on the wheel speed signal, EDS automatically starts to work and uses the hydraulic control unit to brake the wheel with proper strength, in this way, the utilization rate of the drive wheel on the other side is improved, and the vehicle passing capability is improved. When the vehicle's driving status returns to normal, the electronic speed lock stops working. Compared with ordinary vehicles, vehicles with eds can better utilize the ground adhesion to improve the running performance of vehicles. It can be said that EDS is more practical.

Generally, differential locks are only assembled on high-end off-road vehicles, such as Audi Q7, BMW X5, and Mercedes Gl. There are not many models equipped with three differential locks. Generally, only the central differential locks are available.

●Speed table

The speed table is used to display the engine speed. You can intuitively view and know the engine speed, and remind the driver not to exceed the engine speed limit, in case the engine speed is too high to damage its internal parts and affect the safety of drivers and passengers!

The rotation speed is measured in RPM. The current maximum speed of a civil vehicle is generally between 6000-7500 rpm.

●Vehicle computer

The driving computer is also known as the electronic control unit of ECU (electronic control unit. Like a single-chip microcomputer, it consists of a microprocessor (CPU), a memory (ROM, Ram), an input/output interface (I/O), and A/D converter (A/D) and shaping, driving, and other large-scale integrated circuits.

In fact, all vehicles are electronically controlled. That is to say, each car has a computer. The driving computer we refer to here refers to a system that can display information such as outdoor temperature, instantaneous fuel consumption, average speed, average fuel consumption, endurance, and travel time.

●Cruise Control System

The cruise control system is abbreviated as CCS, also known as the cruise control device, speed control system, and automatic driving system. General Motors is the originator of the car's cruise control system. They are the first to use a cruise control system that allows drivers to drive at a constant speed for the 1959 Cadillac series.

Functions of Cruise Control System

After the constant speed cruise system switches at the driver's required speed, it automatically maintains the speed without stepping on the accelerator pedal, so that the vehicle can travel at a fixed speed. With such a device, after a long time of driving on the highway, the driver does not need to control the accelerator pedal to reduce fatigue and unnecessary speed changes, saving fuel.

●HUD head-up Numeric Display

Heads up display (Heads Up Display) is also called the flat display system. It can map important information to a holographic half mirror on the window glass, this allows drivers to see important information without looking down. This display system was originally a display system on a military fighter. the pilot did not have to bow his head, so he could see the necessary important information in the Wind Window. At present, some advanced cars have transplanted it to the car.

The advantages of this display system are:

1. the driver can see the information without looking down, so as to avoid distracting attention on the road ahead.

2. the driver does not have to adjust the eyes between observing the distant road and near the instrument, to avoid eye fatigue.

●Fast-forward System (EPS)

Power steering is to help drivers adjust the direction of the car, to reduce the intensity of the steering wheel, almost all cars are using power steering.

However, there is a problem with the power steering system, that is, it does not know how much power the driver needs. The power is a constant value, so it is not suitable for all driving situations.

At this time, the system was born with the speed of conversion, he was able to change the power of the speed:

During Low-speed driving, the power is greatly increased. For example, when the parking space is in place, the steering wheel is relatively light and the operation is flexible. However, when the speed is low, the steering wheel feels heavy and the vehicle feels stable, good grasp, don't go on the fly. People with a little experience in driving know that this is critical to safety during high-speed driving.

●Tire Pressure Monitoring Device

Tire pressure monitoring device is an alarm device for real-time monitoring of tire pressure. Once the tire pressure is abnormal, an alarm is triggered to remind the driver to check the tires, this effectively avoids accidents caused by tires.

The tire pressure monitoring device uses a pressure sensor installed in each tire to directly measure the tire pressure. It uses a wireless transmitter to send the pressure information from the tire to the system of the central receiver module, then, the tire pressure data is displayed. When the tire pressure is too low or leaks, the system will automatically trigger an alarm.

●Continue without Tire Pressure

Strictly speaking, continuous driving with zero tire pressure cannot be regarded as a configuration. It is only a configuration that plays a role or form of expression. This configuration is called: Explosion-Proof tires, also known as relief tires, RSC.

There are data that indicate that puncture is a very serious safety accident, especially in highway. According to statistics, 70% of highway accidents in China are caused by tires, and the death rate of tires at a speed of more than 160 kilometers per hour is close to 100%. Among all the factors that may result in puncture, tire pressure insufficiency is the primary cause.

Role of Explosion-Proof tires: Continue driving without Tire Pressure

RSC technology has made great progress in safety and comfort. Even if the tire pressure completely disappears to zero, RSC can still enable drivers to continue driving at a moderate speed. Generally, RSC can support driving for 250 kilometers after the tires are cracked, in fact, if a large damage (such as being stabbed by a large area of sharp objects) or a poor road condition occurs, the mileage may be shortened to dozens of kilometers, drivers can drive vehicles to a repair center that is not too far away (not necessarily the nearest repair center), and technicians in the repair workshop can change tires in a more secure manner, this avoids the need to stop at locations with potential accidents due to air leaks.

Another important point is that there is no longer a need to place spare tires, vehicle jacks, or other tools required to replace tires on the vehicle. This means that the vehicle load is reduced, which can improve the vehicle performance and reduce fuel consumption. However, it is necessary to note that the assembly of Explosion-Proof tires does not mean that drivers do not need to perform regular maintenance checks on their tires. Active security awareness must be based on prevention.

At present, the price of Explosion-Proof tires is still much more expensive than ordinary tires, and it cannot be replaced without professional tire Replacement Tools. However, explosion-Proof tires are still one of the most important directions for the future development of automobile tires, because the safety and convenience it brings are what people need. As technology advances, the cost of Explosion-Proof tires will eventually reach a reasonable stage.

●Reversing radar

The reversing radar is a safety auxiliary device for parking or reversing cars. It can provide sound or a more intuitive display to inform drivers of obstacles, the problems caused by the visits between the left and right sides of the driver's parking, reversing, and starting vehicles are eliminated, and the defects of blind spots and blurred lines of sight are eliminated to improve the driving safety.

Nowadays, the average household car is equipped with only rear reversing radar and can only monitor the rear obstacle. The front and even sides of a high-end car are equipped with radar, so that the obstacles between the front and back can be located.

●Visual reversing system

The visual reversing system is also called the car reversing image system. It uses a far-infrared wide-angle camera device installed on the rear of the car and uses the display screen inside the car to clearly display the obstacles behind the car.

Generally, the vehicle-mounted impact system cannot replace the reversing radar, because the camera has a blind zone, and what the human eye sees is often not careful enough. Therefore, reversing images can be used with reversing radar to achieve the best effect.

●Night Vision System

Night vision systems generally use infrared technology to make the darkness look like the day, so that drivers can see farther and clearer in the night. When the two vehicles meet each other, it can greatly reduce the negative visual stimulation of the bright lights in front of the car, and improve the identification ability of the driver driving in the fog.

The night vision system cannot replace the lights. It is only an auxiliary device and the price is relatively high. Generally, it is only assembled on a few luxury cars, such as Mercedes-Benz S-class and BMW 7 series.