How does the power steering system work?

What is power steering?

There are two main types of automotive steering systems: mechanical steering and power steering. Because the design of the mechanical steering system is relatively simple, and the driver’s physical strength is used as the steering energy, the steering wheel is heavy and difficult to turn, so the power steering system has emerged. The power steering system uses external power to help the driver achieve easy steering, just like the power of the foot on the brake. There are three main types of common power steering systems: mechanical hydraulic power steering system (HPS), electronic hydraulic power steering system (EHPS), and electric power steering system (EPS). Among them, the electronic hydraulic power steering system (EPS) is widely used in commercial vehicles, and the electric power steering system is widely used in passenger cars. As environmental protection becomes stricter, the mechanical hydraulic power steering system and the electronic hydraulic power steering system not only have high power consumption but also have hydraulic oil leakage problems, which do not meet environmental protection requirements. The market share of the two is gradually replaced by EPS.

Components of the Electric Power Steering System

The electric power steering system consists of a steering wheel, a steering shaft, a steering booster, a steering screw, a rubber dust cover and a steering tie rod. Since the steering wheel needs to adjust the angle, a universal joint is also installed on the steering shaft to achieve power transmission at different angles.

How does the electric power steering system work?

There is a steering booster device, which is composed of an electric motor, a torque sensor and an electronic control unit. The power supply in this structure comes from the on-board battery. When the steering wheel is working, the power is transmitted to the steering shaft through the steering wheel. After the torque sensor recognizes the steering angle and steering force, it feeds the data back to the electronic control unit. After analysis and processing, the electronic control unit forms the final power-assist command and sends it to the motor. The motor converts it into different sizes of power-assist voltage according to the command requirements to drive the gear shaft of the motor to rotate. Since the gear shaft and the power-assist gear are meshed, the power will be transmitted to the power-assist gear. The force of the power-assist gear and the driver’s manual steering are superimposed to form the final combined torque, which is finally transmitted to the steering screw through the steering shaft to achieve power steering.

Summary:

Different models on the market have different ways of implementing electric power steering. Some power steering mechanisms are installed at the upper end of the steering shaft, while others are installed at the end of the steering shaft. However, the ultimate goal is to help the driver. The power steering is adjustable with speed, and the controllability is good.

What are the design principles of automobile mechanical steering systems?

The system responsible for turning and changing direction of the car is called the car steering system. The commonly used steering systems on the market are mainly divided into two categories: mechanical steering and power steering.

The mechanical steering system is connected by the steering wheel and the steering column. The steering column head is connected to the tie rod between the two wheels. When the steering wheel turns, it will drive the steering column to turn. The steering column will pull the tie rod to the left or right, and the wheels can turn left or right. This is the most basic principle of steering wheel steering. Because this design is too rough, when the steering wheel is not dead, the wheels have already turned to the maximum angle, that is, the steering angle of the steering wheel and the wheel is the same. The industry says that the steering transmission is 1:1, that is, the steering wheel turns the same angle as the steering wheel. This design does not meet the steering parameter regulations of motor vehicles. This design is very dangerous for motor vehicles, because the transmission ratio is 1:1. When the steering wheel turns one degree, the wheel will turn one degree. If the steering wheel turns 5 degrees, the wheel will also turn 5 degrees. If the driver makes a wrong turn on a rugged road due to the shaking of the vehicle, the wheel will respond immediately, which may cause a major traffic accident, which will be very dangerous.

In order to solve this problem, a rack-and-pinion steering design was developed. A bevel gear, also called a helical gear or steering gear, was added to the end of the steering column. This gear meshes with a rack, which is connected to the front wheel through a steering rod. When the steering wheel is turned, the steering gear drives the rack to move left and right, which drives the rod to push and pull the front wheel to achieve a turn. Due to the addition of racks and pinions in this design, the steering transmission ratio becomes smaller. According to the requirements of the national standard, this ratio is between 12:1 and 24:1. Therefore, for a family car, when the wheel is returned to the correct position, the steering wheel needs to be turned one and a half turns before it can be stopped. In other words, the steering wheel needs to be turned three times from the extreme left to the extreme right. Now you should know why the steering wheel is designed to be round.

The current optimized design is still relatively rough, because its steering power transmission is relatively direct, and the steering feedback felt by the hand is also very direct. In layman’s terms, when encountering potholes, the vibration of the wheel will be directly transmitted to the hand through this series of connection components, which is often called the hand-beating phenomenon, and sometimes even the steering wheel cannot be held. Therefore, in order to optimize the design, it was modified again, and the original gear rack type direct meshing connection was changed to a method of using multiple steel balls to transfer power, and the steel balls were used to circulate along the grooves to transmit steering power. In this design, the circular movement of the steel balls in the grooves can effectively absorb the impact from the road surface and play a good shock-absorbing role, so that the driver can get a smoother steering feel. However, this design cost is relatively high, and is usually only used in buses, trucks and off-road vehicles.

Summary:

The steering system optimized by the above two rounds cannot actually meet the safety and comfort requirements of modern cars. The design of the mechanical steering system is relatively simple. It uses the driver’s physical strength as the steering energy, which will require the driver to consume a lot of physical strength. Because the steering force used is different due to different vehicle loads, when using this type of steering system, the steering wheel will be heavy and very difficult to turn.

How to replace a broken car clock spring?

Repairing your car’s clock spring (or spiral cable) can be a little tricky and requires caution, as it is a critical part of your car’s airbag system. It connects the steering wheel to the car’s electrical system, allowing features like the horn, airbags, and cruise control to work while still allowing the steering wheel to turn. It’s not an easy task, so replacing a faulty clock spring is usually a better option than repairing it.

What are the steps to replace a clock spring?

1. Disconnect the battery

Disconnect the battery, safety first. Disconnect the negative terminal of the vehicle’s battery before starting. This prevents any electrical problems, accidental airbag deployment, or short circuits when working around the airbag system and steering column. A simple wrench is enough to loosen the bolt on the negative terminal of the battery. Once loosened, completely unplug the cable from the battery column.

2. Remove the airbag

Be careful when working on the airbag and make sure the vehicle is completely powered off. Use a screwdriver or special tool to unscrew the airbag module from the steering wheel and carefully disconnect the airbag wiring from the clock spring. Once the airbag is out, you may need to disconnect the electrical connector connected to it. On most cars, the airbag is secured by screws or bolts on the back of the steering wheel. Some vehicles also come with a plastic panel that needs to be removed to expose the airbag mounting screws. After removing the airbag, you will find an electrical connector that connects to the vehicle’s electrical system. Gently disconnect it to fully release the airbag. Always be careful when handling airbags, as they are explosive devices. Avoid touching the airbag deployment area.

3. Remove the steering wheel

After removing the airbag module, you will see a large center nut that holds the steering wheel in place. At this time, you can use the steering wheel rail to remove the center nut that holds the steering wheel. Be sure to pay attention to the accurate alignment of the steering wheel on the shaft, as you will need to realign it during installation. If the steering wheel does not come off easily after loosening the center nut, you may need a steering wheel puller. This tool can help remove the steering wheel without damaging the column or clock spring underneath. Before removing the steering wheel, mark its position on the steering column with a marker so that it is accurately aligned when reassembled.

4. Locate and check the clock spring

The clock spring is a coiled wire device located just below the steering wheel. It is essential for maintaining electrical connections for devices such as the horn, airbags, cruise control, and steering wheel buttons, while allowing the steering wheel to rotate freely. The clock spring may be secured with screws or clips. Remove these fasteners with a screwdriver, then carefully pull out the clock spring. Be sure not to yank on the wires, or they will be damaged. Look for any visible damage, such as broken wires, fraying, or obvious cracks in the plastic casing. If you find any problems, replace them in time.

5. Replace the clock spring (if damaged)

If the clock spring is broken, you need to replace it with a new one. Be sure to get the correct part number and make sure the replacement clock spring matches the model and year of your vehicle. If you are unsure, you can get the part number from the damaged car and consult an auto parts supplier. Before installing a new clock spring, make sure the internal coil is properly aligned (do not over-wind or loosen it). If the coil is not aligned, it may break when the steering wheel is rotated. Some clock springs have indicators (such as arrows) to show the correct alignment. Slide the new clock spring into place and secure it with screws or clips to ensure it is properly seated. Make sure the spring is centered so it has a full range of motion and does not break when you reinstall the steering wheel.

6. Reinstall the steering wheel

Put the steering wheel back together, making sure the clock spring is aligned correctly. Align the steering wheel with the mark you made earlier and bolt it back to the steering column, tightening the center nut. Reinsert the airbag’s electrical connector and secure the airbag module back to the steering wheel. Make sure the mounting bolts or screws are tight. Once everything is back in place, reconnect the battery and tighten it. Carefully reassemble everything, starting with the steering wheel, airbag module, and electrical connector.

7. Test the system

After reassembly, check to make sure everything is working properly. Turn on the vehicle and check the airbag light on the dashboard, test the horn, cruise control buttons, and any other steering wheel controls to make sure everything is working properly.

Tips:

During the operation, work carefully and slowly, and never break or misplace parts because of haste. Always be careful when operating the airbag. Improperly aligning the steering wheel during operation can cause the clock spring to break when you turn the steering wheel, so make sure it is positioned exactly as it was before removal.

What is Tire Pressure Monitoring Sensor (TPMS)?

Tire Pressure Monitoring Sensor (TPMS) is a tire pressure monitoring sensor. It is used to monitor the internal pressure (and sometimes temperature) of the tire in real time and transmit the data to the in-vehicle system. It can alert the driver when the tire pressure is abnormal (too high or too low), helping to ensure driving safety and vehicle performance.

What are the main components of TPMS?

1. Pressure Sensors

Installed in each tire, they measure the tire pressure and temperature in real time. There are usually two ways: direct TPMS, where each tire has an independent sensor that directly measures the pressure. Indirect TPMS, which does not use independent sensors but infers pressure changes by monitoring the speed difference of the tires through the vehicle’s ABS system.

2. TPMS Control Module

Receives data from the sensor and processes and interprets the information based on changes in tire pressure. If the tire pressure is detected to be too low or too high, the control module will alert the driver.

3. Warning Indicator

Usually located on the vehicle dashboard, it will light up the warning light when the tire pressure is lower than the safe value to alert the driver. Common indicator lights are symbols shaped like tire pressure or display specific pressure values.

4. Antenna/Receiver

Responsible for receiving the wireless signal sent by the tire sensor and passing it to the TPMS control module.

5. Sensor Battery

Provides power to the tire pressure sensor. Sensor batteries typically have a lifespan of 5-10 years, and the sensor needs to be replaced when the battery is exhausted.

How does the common water cooling system work? What are the big cycle and the small cycle?

When the engine is working, the temperature of the cylinder combustion chamber can reach 2000-2500 degrees. Long-term operation will cause the engine temperature to be too high and affect performance, and even damage the parts. The cooling system is responsible for dissipating the heat of each part in time to prevent them from overheating. Common cooling systems are mainly divided into two categories: air cooling system and water cooling system. Because the water cooling system cools evenly, takes effect quickly and has low noise, it is widely used in household engines.

The water cooling system is mainly composed of a water pump, a radiator, a cooling fan, a thermostat, an engine body water jacket, a cylinder head water jacket, and a water pipe loop. After the engine is started, the water pump will be driven to work. Under the action of the water pump pressure, the coolant begins to enter the engine body water jacket from the water pipe. Since the engine body water jacket is distributed around the cylinder, the coolant will absorb heat when it flows through, and then continue to flow into the cylinder head water jacket, and then absorb heat from the cylinder head water jacket again and flow out, and then enter the thermostat. The thermostat is a temperature control valve that can automatically adjust the opening and closing of the valve according to the temperature to control the flow direction of the coolant. When the engine is just started, the temperature of the coolant is low. Under the control of the thermostat, the coolant flows directly back to the water pump, and then flows to the engine body again after being pressurized by the water pump. In this cycle, since the coolant flows in this small range of the water pipe loop, it is called a small cycle. The radiator does not participate in the work during the small cycle, so the heat of the engine will not be lost, which is conducive to engine warm-up. Therefore, in winter, you need to wait a few minutes after starting the vehicle before starting it again. This is conducive to the preheating of various engine parts and has the function of protecting the parts. After the engine has been running for a period of time, the temperature of various parts rises, and the temperature of the coolant also rises accordingly. When a certain temperature is reached, the thermostat will gradually open the valve leading to the radiator. At the beginning, the valve opening is small, and only part of the coolant will flow to the radiator. After the radiator dissipates heat and cools down, it returns to the water pump through the water pipe. This process is called a large cycle.

At the same time, another part of the coolant will flow directly back to the water pump through the thermostat. Therefore, both the large and small cycles will participate in the work in this process, and they work together. When the engine temperature continues to rise and the coolant temperature exceeds the standard value of the thermostat temperature, the thermostat valve will be fully opened, and the valve leading to the water pump will be automatically closed. At this time, all the coolant will flow to the radiator and enter the full large circulation mode. In this process, the coolant passes through the radiator and dissipates heat and cools down under the action of the cooling fan, and the heat is finally dissipated into the air. The cooled coolant continues to flow to the water pump through the pipeline, and the engine’s heat dissipation work continues in this way over and over again. This is the complete working process of the engine cooling system.

In conclusion, the component that prevents the engine from overheating is the thermostat. When it detects that the temperature rises, it will open the valve to start the heat dissipation function, so that the coolant can continue to cool the engine. The small circulation mode of the coolant is conducive to the preheating of the engine. It is best to warm up the engine for a few minutes before driving in winter, which helps protect the parts. The large circulation mode of the coolant system is a complete heat dissipation mode, at which time the cooling system fully dissipates heat for the engine.

What is PDC reversing radar?

Park Distance Control (PDC) is also commonly referred to as reversing radar. As an important safety auxiliary device in modern cars, PDC system mainly consists of ultrasonic sensors (commonly known as probes), controllers and displays (buzzers). When reversing, it helps the driver “see” things that the rearview mirror cannot see, and informs the driver of the surrounding obstacles with a more intuitive sound display, eliminating the trouble caused by the driver looking around when parking, reversing and starting the vehicle, and helping the driver eliminate the defects of blind spots and blurred vision, thereby improving driving safety.

How does PDC parking radar work?

The working principle of the reversing radar is based on sound wave technology, which uses ultrasonic sensors. It transmits and receives sound waves through the ultrasonic sensor installed at the rear of the car. When the sound waves encounter obstacles, they will be reflected back, and then the system will calculate the distance and position of the obstacle. The controller will process these signals. When the distance reaches the preset safety range, the display or buzzer will issue a warning. For example, when we put the car in reverse gear and turn on the reversing radar system, the sensor will emit ultrasonic beams to the rear of the car. These beams will bounce and return to the sensor. The sensor can measure the time difference of these beams to calculate the distance and position of the obstacle from the car. Specifically, the reversing radar will emit hundreds of ultrasonic waves, which propagate at a very fast speed and interact with obstacles. When the beam hits the obstacle and returns, the sensor can measure the time difference of the beam. By calculating the speed of the sound wave, the system can determine the distance between the obstacle and the car. These distance data will be transmitted to the display screen inside the car and displayed to the driver in a visual way. When the vehicle approaches an obstacle, the PDC system will alert the driver through the alarm system, either with a beep or a display on the dashboard, telling the driver to pay attention to nearby obstacles and avoid collisions.

What is the role of the PDC reversing radar?

In terms of safety assistance, it can help the driver better judge the distance between the vehicle and surrounding objects, especially when the line of sight is limited. With it, driving and parking in narrow spaces are safer. In terms of avoiding accidents, it is easy to ignore potential dangers when reversing due to limited vision, but PDC can issue an alarm in time to effectively reduce the risk of reversing collision accidents. Not to mention the convenience of parking, it not only improves safety, but also makes parking super convenient, allowing drivers to park the car more easily, reducing tension and improving the overall driving experience.

How does a car’s hydraulic brake system work?

A speeding car can stop immediately by stepping on the brakes when it encounters an emergency. So what principle does the car use to brake and stop? In modern cars, the hydraulic brake system is the most commonly used brake system, which is what we often call the brake system. The principle of hydraulic braking is to seal the liquid in the brake line without air. Because the liquid cannot be compressed and can transmit power 100%, when the liquid is pressurized, the liquid transmits the pressure through the pipeline to the piston of the brake caliper of each wheel. The piston drives the brake caliper to clamp the brake pad, thereby generating huge friction to slow down the vehicle. Since the liquid can bend without being affected by the pipeline route, hydraulic braking is currently the most effective braking solution.

So what parts does the automobile hydraulic brake system use to achieve braking? First of all, there are brake pedals, brake push rods, brake control modules installed in iron boxes, master cylinders, brake oil tanks, and brake lines. When the driver steps on the brake pedal, mechanical force is transmitted to the brake push rod, which transmits power to the brake control module. The control module converts the mechanical force into vacuum liquid pressure and transmits it to the sealed master cylinder. The piston in the master cylinder pushes the brake oil to the four brake lines under the action of hydraulic pressure. When the pressure is released, the brake oil returns to the master cylinder. There must be enough brake oil in the tank to prevent it from entering the hydraulic system. When the wheel brakes, the brake pedal is stepped on. The brake control module converts the mechanical force into liquid pressure and pressurizes it, causing the brake oil in the master cylinder to flow to each brake line. The pressure of the brake oil is transmitted to the piston of each wheel brake caliper through the pipeline. The piston drives the brake caliper to clamp the brake disc and slow down the wheel. When the brake pedal is released, the brake oil returns to the master cylinder, the piston of the wheel brake caliper is released, and the wheel starts to turn again. This is the working principle of the hydraulic brake system.

How to adjust the rearview mirror?

We all know that improper adjustment of the car’s rearview mirror will create blind spots and increase driving risks. The ultimate goal of adjustment is to coordinate the three rearview mirrors to minimize the rear blind spot. A car has three rearview mirrors, namely the interior rearview mirror and the exterior rearview mirrors on both sides. The interior rearview mirror is mainly used to observe the situation of the vehicle behind, while the exterior rearview mirror is mainly used to observe the situation of the vehicle behind. Due to the different heights and observation angles that each of us is used to, the refracted images we see in the rearview mirror are also different. Therefore, before driving, you need to adjust the rearview mirror so that you can clearly observe the road conditions behind from the rearview mirror before you can go on the road. This is very important for driving.

First of all, when adjusting the interior rearview mirror, the most important point is to make the rear window glass fully present on the rearview mirror, so as to maximize the rear view and reduce the blind spot. After adjusting the interior rearview mirror, the horizon in the distance should be placed in the midline position, and the image of the right ear is just on the left edge of the mirror. When adjusting the exterior rearview mirror, we can press the left roller button on the steering wheel to choose whether to adjust the left or right rearview mirror. Then use the electric switch or manual adjustment to make the rearview mirror move up, down, left and right. When we adjust the left rearview mirror, we need to tilt our head toward the driver’s side glass (on the glass) until you can just see the rear of your car, so as to avoid repeated coverage of the range of the interior rearview mirror. After adjusting the left rearview mirror, the horizon should be placed in the midline position, the edge of the car body occupies 1/4 of the mirror image, and at the same time ensure that there is enough space on the side to observe other vehicles. When adjusting the right rearview mirror, we need to tilt our head to the right in the same way as the left side, until you can just see the rear of your car, so as to avoid repeated coverage of the range of the interior rearview mirror. After adjusting the right rearview mirror, the horizon should be placed at the 2/3 position, the edge of the car body should occupy 1/4 of the mirror image, and at the same time ensure that there is enough space on the side to observe other vehicles.

After the above adjustments, when a car passes you, you can see it in the rearview mirror first, and clearly know the road conditions behind, which can effectively improve driving safety. Of course, adjusting the rearview mirror does not mean that you can completely rely on it. During driving, we also need to pay attention to the changes in the surrounding environment at any time, whether there are other hidden obstacles or pedestrians, so as to ensure safe driving. In addition, before adjusting the rearview mirror, you should first adjust the position of the steering wheel and seat.

How do car fuel injectors work?

The engine fuel injector is a very important part of the engine. Its function is to spray fuel accurately according to the needs of the engine to achieve the best combustion effect. When the engine is started, the fuel pump pumps the fuel from the fuel tank, passes through the fuel filter and enters the injection channel of the fuel injector. At the entrance of the injection channel, the fuel is pushed by the high-pressure gas through the spray hole into the cylinder. In the cylinder, the fuel mixes with the high-temperature gas in the cylinder to form a combustible mixture. The size of the injection hole in the fuel injector can be adjusted as needed to control the amount of fuel injection to achieve the best combustion effect. In addition, the solenoid valve in the fuel injector can control the injection timing of the fuel according to the needs of the engine, making the fuel injection more accurate. Finally, the exhaust gas after combustion is discharged through the exhaust pipe and becomes the energy to drive the vehicle. The fuel injector plays a vital role in the engine, and its performance directly affects the performance and emissions of the engine.

What are the benefits of regular fuel injector cleaning?

After a long period of use, the problem of carbon deposits will gradually emerge. The reason for carbon deposits in the engine is very simple, that is, a kind of charred substance is produced under high temperature conditions by unsaturated olefins and colloids in the fuel. When this substance accumulates on the fuel injector, it will affect the fuel injector and cause the fuel injection to be poor, the injection angle, poor atomization, etc. In severe cases, it may even cause the fuel injector to be blocked, so it is very necessary to clean the fuel injector. The carbon deposit problem of the fuel injector will cause a serious drop in engine power, and when the fuel injector is cleaned, the engine power will be improved and restored to the best state. When the fuel injector is not spraying smoothly, the engine will shake significantly during operation, so when the fuel injector is cleaned, the engine shaking problem will be improved. After the fuel injector is cleaned, the problem of vehicle exhaust emission pollution can be improved.

What is the difference between an electronic thermostat and a mechanical thermostat?

The mechanical thermostat works on the principle of thermal expansion and contraction of paraffin, and controls the opening and closing of the thermostat by the temperature of the coolant. The center of the electronic thermostat is also filled with paraffin, but a heating device is installed inside the paraffin. This heating device is controlled by the electronic control unit ECU. The electronic control unit captures signals based on the engine water temperature sensor and the water temperature sensor on the radiator tank. When these signals reach the values set by the electronic control unit ECU, a heating instruction will be sent to control the heating of the heating device and the heating temperature can be accurately controlled. This is the implementation principle of the electronic thermostat. The electronic thermostat is more advanced than the mechanical thermostat. The main point is that the electronic control unit can dynamically control the heating of the heating device based on the sensor data of various sensors of the engine. That is to say, when the coolant has not reached the melting temperature of the paraffin, the electronic control unit can also control the melting of the paraffin in advance. This control is determined by the engine based on the sensor data of each sensor. The mechanical thermostat cannot achieve this effect. It can only start working after the coolant reaches a certain temperature. The above is the difference between mechanical and electronic thermostats.