By understanding this automotive knowledge, you can save half of your regular maintenance costs and get a full load of dry goods

Today, I have compiled some common sense knowledge about the use, maintenance, and repair of automobiles, and shared it with everyone. After learning this, you will become a half car expert. Let's start learning!

What is the relationship between the number of cylinders in an engine and the engine speed?

There is no direct relationship. But generally speaking, under the same cylinder diameter,automotive industry supply the more cylinders, the larger the displacement, and the higher the power; At the same displacement, the more cylinders there are, the smaller the cylinder diameter, and the corresponding increase in rotational speed, thus obtaining greater power.

What is the impact of wheelbase length on?

Wheelbase refers to the distance between the front and rear axles. It will affect handling performance, minimum turning radius, body stiffness, indoor space, chassis carrying capacity, etc.

Why do I need to disconnect the negative electrode when cutting off the power supply?

Because all control units, actuators, battery negative wires, and switches of the vehicle are grounded through the vehicle body, in other words, after disconnecting the battery negative pole, even if the tool touches the live wire during operation, it is not afraid of causing a short circuit to the ground.

If the positive battery wire is disconnected, any point between the positive battery and the vehicle body may cause a short circuit to ground. Very dangerous!

What are active safety systems and passive safety systems?

An active safety system is a device on a vehicle that can prevent accidents before they occur.automotive industry services For example, ABS, EBD, ESP, anti glare rearview mirrors, and so on.

Passive safety systems are devices that can protect members of a vehicle in the event of or after an accident, such as airbags, seat belts, active headrests, safety battery terminals, fuel pump cut-off system, collapse zones in the front and rear compartments, sturdy seating areas, and so on.

How should a battery be maintained daily to extend its lifespan?

Nowadays, most batteries are maintenance free, and the following issues should be noted to extend their service life:

(1) Do not frequently drive short distances;

(2) Do not discharge excessively, that is, do not use the electrical appliances in the car for a long time after turning off the engine;

(3) When parking for a long time (more than three months), it is necessary to regularly charge/or turn the battery switch to OFF, or remove the negative electrode of the battery.

Why not use water instead of coolant for water tank water?

Because compared to water, coolant has the characteristics of rust prevention,automotive industry solution high boiling point (if water is used, it boils at around 100 degrees Celsius), and low pour point (if water is added, the water will freeze when the temperature is below 0 degrees Celsius, which will seriously damage the water tank, auxiliary water tank, water pipe, engine, etc.). Furthermore, in areas with poor water quality, such as hard water (with more minerals), scale can also form in the cooling system, affecting the cooling effect.

What are the characteristics of M, D, and S in automatic transmissions?

After shifting to D gear, moving the shift lever towards the driver's side can switch from D to S mode. If the shift lever is moved forward/backward at this time, it can enter M mode from S mode.

D mode: D gear for ordinary automatic waves;

S mode: In sports mode, the transmission shifts to a higher gear only when the engine is at a higher speed, and the transmission does not shift to the highest gear (overdrive);

M mode: Hand wave mode, press the+/- buttons to manually increase or decrease gears.

Is oil consumption greater in summer than in winter?

This argument is unreasonable because the normal engine operating temperature is maintained at around 80-105 degrees Celsius, regardless of whether it is summer or winter. So for engine oil, there is not much change in operating temperature, so the consumption of engine oil is roughly the same.

Why do cars emit white smoke in winter?

When high-temperature exhaust gas is discharged from the exhaust pipe and encounters cold air, it releases heat and condenses into water vapor to form white smoke. This is a normal phenomenon.

What are the reasons for white smoke, black smoke, and blue smoke emitted by cars?

White smoke: mainly water vapor, which is particularly noticeable when driving in cold winter. It is normal for the car to disappear after a short period of time. However, if white smoke is sprayed for a long time and there are many water droplets from the exhaust pipe, it is necessary to consider whether the car has entered the water or engine punch.

Blue smoke: It is likely to burn engine oil. Check the oil level, crankcase ventilation valve, broken/stuck piston rings, etc.

Black smoke: If the mixture is thick, check for gasoline pressure, fuel injector leakage, and blockage in the pipeline from the air flow meter to the intake valve, which may result in carbon buildup.

What should I pay attention to when parking a vehicle for a long time?

It is recommended to charge the battery every three months; Set the tire pressure higher than the standard to prevent local compression and deformation of the tire. If possible, it is best to regularly rotate the tire to avoid prolonged contact with the ground at the same point; Do not apply the handbrake; Do not place it under a tree to prevent the sap from damaging the paint surface. If possible, it is best to place it in a place that can avoid direct sunlight; The oil level should be checked before each landing. If the storage time is too long (one year or more), the oil must be changed before starting the car.

What is the impact of adding too much oil?

If there is too much oil, it is easy to increase engine resistance and fuel consumption; Moreover, excessive oil can jump into the combustion chamber, causing the engine to burn oil, resulting in a significant increase in oil consumption, increased carbon deposition inside the engine, and even leading to premature ignition and detonation, seriously damaging the engine.

Why is there white smoke coming out after tightening the oil filler cap?

Part of it is engine oil vapor, and it is also possible that some of it is water vapor. The temperature inside the engine is high, and the gas in the engine can accommodate more water molecules. When the oil cap is opened, gas escapes and the outside temperature is low. As the temperature drops, the ability of the gas to hold water molecules decreases, and some water molecules become supersaturated and precipitate in the form of water vapor. Similar to the principle of exhaling white air from our mouths in winter.

How does the starting motor work?

The starting magnetic suction causes the starting motor pinion to slide out and mesh with the flywheel, and the motor drives the pinion to rotate the engine flywheel. After landing, the pinion returns to its original position to prevent damage by the high-speed flywheel. The starting motor stops working after the engine starts.

What is the function of the oxygen sensor in the exhaust system?

Measure the oxygen content in the exhaust gas and provide information to the ECU to analyze the combustion status of the engine, enabling the ECU to achieve an ideal air fuel ratio (14.7:1) by adjusting the fuel injection rate.

What is timing adjustment and what is its function? What are the consequences of inaccurate timing?

In fact, the timing is divided into ignition timing and valve timing. Due to the fact that the ignition timing is controlled by the ECU and is rarely involved in general maintenance, the commonly used term "timing adjustment" refers to adjusting the valve timing, which means fixing the crankshaft, intake and exhaust camshaft in a unique mating position through a timing chain or belt. Correct valve timing can improve accurate valve opening and closing time, improve inflation efficiency, and reasonably reduce emissions. Inaccurate timing can lead to poor engine power, excessive emissions, backfire, difficulty starting, high gasoline consumption, engine shaking, and other adverse phenomena. If the timing is completely incorrect, the car may not start, and in severe cases, it may even damage the engine.

What is the reason for the low water temperature?

A common possibility is that the opening time of the thermostat is incorrect (normally open) or the cooling fan is not working properly (usually on high speed). There may also be other possibilities that require specific analysis of specific issues.

Low water temperature is not a good thing! The main hazards include: low engine temperature, excessive heat absorption from cylinder walls, reduced thermal efficiency and output power, and increased fuel consumption. The engine temperature is too low and gasoline is not easy to evaporate, making combustion difficult. At the same time, some gasoline that forms small droplets will wash the lubricating oil on the cylinder wall and flow into the oil pan with the lubricating oil, not only causing fuel waste, but also diluting the lubricating oil, affecting lubrication function, and accelerating the wear of the piston and cylinder wall. The lubricating oil temperature is too low and thickens, preventing it from flowing smoothly to the surface of some relatively moving parts, resulting in poor lubrication and increasing the resistance to movement of the parts.

What is the function of a knock sensor?

The knock sensor is used to monitor whether each cylinder of the engine is operating in a knock state. If so, it will adjust the ignition time of the cylinder to ensure smooth engine operation. Knock sensing controls the engine at a critical point close to detonation. If detonation is detected, it will delay the ignition time and reduce the severity of combustion.

What is the function of a thermostat?

The function of a thermostat is to open or close the valves of the large and small circulation channels based on the water temperature, controlling the flow of engine coolant in large or small circulation. When the engine is cold, the water tank is closed, and the water in the water tank circulates in the engine water channel (i.e. "small cycle") without cooling through the water tank. Therefore, the water temperature can quickly rise to the normal operating temperature of the engine. When the temperature continues to rise, the thermostat opens and water from the water tank can flow into the tank, thereby controlling the temperature not to rise again.

What is the function of crankshaft position sensing?

The function of crankshaft position sensing is to let the DME know where each cylinder piston of the engine is running and the engine speed. At the same time, its signal can also be used to diagnose misfires.

Under what circumstances will the engine knock?

Excessive clearance or poor lubrication between the piston and cylinder wall can lead to knocking (cold knocking), or it may be the metal sound generated by the collision between the shock wave generated by detonation and the rising piston (hot knocking).

Knocking the cylinder (the irregular "clang" and "dangdang" metal knocking sound inside the engine) is mainly caused by detonation. It will suddenly produce detonation in the cylinder and impact in all directions, causing abnormal noise from the side of the engine piston hitting the cylinder wall. At the same time, strong vibration and impact will occur on the connecting rod, crankshaft, and other components, accompanied by metal impact sound. Common causes:

a. Poor gasoline quality is prone to detonation. (I have tried some cars, whether they are cold or hot, and I may hear a knocking sound when idling in place and refueling urgently.)

b. If the engine temperature is too high, the combustion speed and pressure inside the combustion chamber will increase, which can also cause detonation.

c. When the engine is driven at low speeds and short distances for a long time, a large amount of carbon deposits will gradually form in the combustion chamber. As the carbon deposits occupy the space of the combustion chamber, it will cause an increase in the compression ratio of the engine, ultimately leading to an increase in combustion temperature and pressure. At the same time, due to the adiabatic nature of carbon deposits, when the engine is running at high speed, the carbon deposits retain the heat from the previous work. When the mixture pressure is compressed to a certain pressure and temperature, the heat stored in the carbon deposits will ignite the mixture, forming irregular combustion and causing detonation noise. This is commonly referred to as spontaneous combustion and multi-point combustion.

What is the impact of knocking on the engine?

(1) Long term knocking on the cylinder can affect the engine's lifespan, and in severe cases, it can even result in high oil consumption, broken pistons, and damaged cylinder walls.

(2) The engine shakes and the power decreases.

(3) The engine operating temperature is too high.

(4) Incomplete fuel combustion, black smoke in exhaust gas, and increased gasoline consumption.

What is the impact of dirty gasoline on cars? How to solve it?

Dirty gasoline can have a significant impact on the fuel system of a car, leading to clogging of the gasoline grid, poor fuel injection at the fuel injection nozzle, failure of the fuel pump, increased oil pressure, poor fuel atomization, engine shaking, misfire, decreased power, inability to refuel, and increased carbon deposition. Not only does it have an impact on the engine, but poor gasoline can also seriously damage the three-way catalytic converter. Once the three-way catalytic converter is blocked, problems such as weak refueling and abnormal exhaust pipe noise can also occur. If it is an iron gasoline tank, it will also rust due to the high water content of the gasoline, increasing the adverse impact on the fuel system. Solution: It is recommended to only refuel at large and reputable gas stations, add high-quality fuel, and regularly replace the gasoline grille. It is best to regularly clean the gasoline tank and nozzle.

The gasoline tank is saddle shaped, which side of the fuel should be used first?

When the oil is full, the oil on the left and right sides first decreases synchronously, and only when it reaches the saddle position does the difference in liquid level between the left and right appear. The drainage pump installed on the base of the fuel buffer device is used to supply fuel to the fuel buffer device. In addition, there is also a drainage pump under the left side of the fuel tank, which guides the oil from the left tank to the right tank

What is the difference in the installation of the half axle between front and rear drive vehicles?

The half shaft, also known as the drive shaft, transmits power to the wheels through the half shaft. Both ends of the half axle have universal joints, which ensure uninterrupted power transmission when the wheels swing on the suspension. The half axle of the front wheel drive vehicle is connected to a wave box at one end and a wheel at the other end; The half axle of a rear drive vehicle is connected to the tail gear at one end and the wheel at the other end.

What is the function of the universal joint of the transmission shaft? Why is there a universal joint?

A car is a moving object. In cars with front engine and rear wheel drive, the engine, clutch, and transmission are installed as a whole on the frame, while the drive axle is connected to the frame through elastic suspension, with a distance between the two that needs to be connected. During the operation of a car, uneven road surfaces can cause bouncing, load changes, or differences in the installation positions of two assemblies, which can cause changes in the angle and distance between the transmission output shaft and the input shaft of the drive axle main reducer. Therefore, a "variable strain" device needs to be used to solve this problem, resulting in the existence of a universal joint.

Similarly, this universal joint is required as a 'joint' between the transmission and transfer case, as well as between the front drive steerable drive axle and the half shaft. The structure and function of a universal joint are somewhat similar to those of joints on human limbs, allowing for changes in the angle between the connected parts. But it differs from the form of movement of limb joints, as it only allows the angle to change within a certain range.

What is the relationship between the thickness and width of tires and driving and fuel consumption?

If the 'thickness of the tire' referred to here refers to the 'flat ratio' of the tire, the flatter the tire, the wider it is (i.e., the smaller the 'flat ratio'), and the larger the contact area with the ground, the better the grip, but at the same time, the resistance also increases, the fuel consumption will be higher, and the shock absorption effect will be lower. So it is necessary to choose suitable tires based on the actual requirements of the vehicle, rather than necessarily the more expensive and wider the flat tires, the better.

What is the impact of tire size on driving?

Firstly, the design of the suspension determines the optimal tire size for this vehicle. Replacing a tire with a diameter that is too large or too wide can affect installation or cause interference with the suspension components;

Secondly, replacing a wheel with a diameter that is inconsistent with the original wheel will affect the accuracy of the odometer and speedometer;

Thirdly, the size of the width will affect fuel consumption, steering flexibility, driving stability, and safety.

Under what circumstances will the side of the tire bulge?

The tire is subjected to high-strength impact, resulting in the tensile deformation and fracture of the steel wire inside, such as passing through pits or obstacles at high speeds. In principle, tires with bubbles should not be used again. Otherwise, once driven at high speeds or over long distances, the tires will burst from the bubble, causing adverse consequences.

What is the impact of inconsistent front and rear tire patterns on driving?

The traction of the front and rear wheels is different, which can affect the stability of the vehicle when driving at high speeds. Moreover, when turning at high speeds, due to the different front and rear tire patterns and adhesion, the magnitude of lateral force is also different, resulting in different lateral displacement between the front and rear axles. If the lateral displacement of the front axle is greater than that of the rear axle, there will be understeer; If it is smaller than the rear axle, excessive steering may occur, and in extremely severe cases, it may cause tailspin. So, try to maintain consistent tire patterns on the front and rear axles