Diesel engines are powerful and fuel efficient, why don t cars use them

Most of today's car engines are gasoline engines, but why don't all cars use fuel-efficient and powerful diesel engines?

There are two sides to everything, and the same is true for a diesel engine. In fact, the diesel engine has many advantages, such as it will be more powerful, and the low-torque output will be more powerful. Moreover, it is more fuel-efficient than gasoline vehicles, and because of its simple structure, it will be cheaper to maintain.

These are the benefits of a diesel engine, but what are its disadvantages? We all know that the ignition method of diesel engine is compression-ignition, compared with gasoline vehicles, it does not have a spark plug structure, and sometimes toxic gases will be produced due to insufficient oxygen, such as toxic gases such as NOx will be emitted into the air, resulting in pollution. Because of this, diesel vehicles are equipped with urea tanks that can neutralize this toxic gas to prevent it from polluting the atmosphere.

Sometimes this has become a reason to limit the development of diesel vehicles, and it has also exposed many scandals in the automobile industry.

The advantages and disadvantages of diesel engines are very obvious. The advantages are high torque and low fuel consumption, and the disadvantages are large volume and weight, high vibration and noise, and high technical standards. Another point is that in order to achieve the same comprehensive effect in the vehicle engine, the technical requirements for the manufacture and maintenance of diesel engines are much higher.

For example, the machining accuracy of the fuel supply pump and fuel injector on the general diesel engine is not at all on the best gasoline engine! On both assemblies, many parts require zero errors in fit (coupling).

If it is used on the diesel engine according to the standard of firmware particulate in gasoline and the standard of gasoline filter element, these two high-precision parts of the diesel engine may be scrapped in a few working hours. To install the diesel engine in the car, in addition to choosing a diesel engine with a much higher standard than the gasoline engine, it is also necessary to invest more costs than the gasoline engine in shock absorption and sound insulation to achieve the same effect. In terms of maintenance, the investment in the inspection, debugging and calibration of oil pumps and nozzles is much higher than that of gasoline engines.

Repair is an impossible fantasy. Because the assembly requires constant temperature, constant humidity, and dust-free environment, technically, the 4S store does not even have tools. All the seemingly neat 4s simply don't have it.

A large number of popularization of diesel family cars in industrial finishing, the overall technology of automobiles, China still has a way to go.

China's diesel standards are much lower than those of foreign countries, resulting in lower emission standards for household diesel vehicles. Although the quality of domestic gasoline has been criticized, compared with diesel, the quality of gasoline is no longer better. Inferior oil products have led to many owners who choose diesel models to have to repair their cars frequently; Due to reasons such as diesel fuel is not volatile and compression ignition, cold start in winter is not as good as gasoline engine.

Even if there is a preheating device, it should be preheated for tens of seconds before it can be started.

Whether a diesel engine or a gasoline engine is used depends on the occasion of use and the large load Usually the diesel engine is used for the occasion of large load, and the gasoline engine is used for the occasion of small load. In addition, due to the construction principle and combustion mode, the diesel engine can be larger, but the gasoline engine is difficult to achieve large-scale; The gasoline engine has little potential, and the diesel engine has a large potential.

Generally speaking, the engine is used, and it may not be very suitable for environmental protection requirements, and it is not very suitable for modern environments.

From the theoretical perspective of thermodynamics, the basic principle of improving engine power and economy is to improve the energy quality after fuel efficiency heating, that is, to increase the average temperature of the working fluid in the heating process as much as possible and reduce the average temperature of the heat release process to the environment as much as possible under the same heating amount. In the existing cycle mode, there are three main implementation directions:

1. Under allowable conditions, increase the compression ratio of the engine as much as possible.

2. Rationally organize the combustion and improve the isochorance of circulating heating, that is, by reducing the pre-expansion ratio of the cycle and reasonably selecting the phase of the combustion starting point, the combustion heating center is close to the top dead center.

3. Ensure that the working fluid has a high isentropic index. However, under the calibration conditions, the actual diesel engine is closer to the isobaric cycle than the gasoline engine. Because the compression ratio of the diesel engine is much higher than that of the gasoline engine, and its maximum combustion burst pressure is much higher than that of the gasoline engine, its thermal efficiency is higher than that of the gasoline engine.

Precautions for the use of diesel vehicles.

Diesel is a complex blend of hydrocarbons, so it is more difficult to ignite and is a relatively safer choice as a fuel. The quality of diesel fuel is the guarantee of the operation of the diesel engine, and inferior diesel fuel containing moisture or impurities can cause serious damage to the high-pressure distribution pump. Therefore, the best way for users is to choose the gas station carefully, and ask for a ticket after refueling.

If the gas station staff mistakenly adds gasoline, the owner should not start the car, and should immediately contact the repair station or 4S shop for technical support.

Diesel vehicles are more fuel-efficient than gasoline vehicles, which is determined by the technical characteristics of the engine.

Because the compression-ignition diesel engine has a higher energy conversion than the ignition gasoline engine, the energy consumption is 45%-60% of the gasoline engine, and the diesel ** is lower than the gasoline**, the engine has less complex high-pressure ignition device than the gasoline engine, and the life is generally longer than the gasoline engine product, so the fuel economy of the diesel engine is better than that of the gasoline engine. At the same time, diesel engines also have outstanding advantages over gasoline engines in terms of safety and environmental protection.

Diesel fuel is not volatile, has a high ignition point, and is not easy to be ignited or occur due to accidental circumstances**; The emission of carbon dioxide is also about 30%-35% lower than that of gasoline engines, and the exhaust emissions of diesel vehicles are better than those of gasoline vehicles. In addition, the diesel engine is also very small in terms of power and gasoline engine, some performance parameters are even better than gasoline engine, for example, the low-speed torque of diesel engine is relatively large, which is reflected in the diesel car climbing ability is stronger than gasoline car, and the acceleration at low speed is faster than that of gasoline engine. At present, the diesel quality in most parts of the country simply cannot meet the requirements of the latest Euro III and IV emission standards for diesel engine technology, and the fuel with higher sulfur content will not only lead to the deterioration of the diesel vehicle emission system, but also shorten the engine life and increase the repair and maintenance costs.

In addition, most of the domestic consumers' awareness of modern diesel engines is still very low, and most people still stay in the 70s of the last century on the understanding that the black smoke is billowing and the noise is unbearable, and there will be great resistance to diesel cars. With the development of new diesel engine technology, diesel vehicles have made great progress in exhaust emissions and noise reduction.

Features of both engines:

After the mixed gas in the gasoline engine is ignited, it burns instantaneously and bursts out of energy, so the cycle can be repeated many times in a unit time, and the high power output is at a high speed, but the compression ratio of the gasoline engine is often only half of that of the diesel engine, and the temperature and pressure in the cylinder are much lower than that of the diesel engine when doing the power stroke, so the thermal efficiency is relatively low, which is commonly known as "fuel consumption".

After the diesel engine is injected with fuel, it takes a certain amount of time to burn. Because of the characteristics of high compression ratio and low speed, diesel engine can better convert heat into kinetic energy, so diesel engine has better thermal efficiency, that is, better fuel consumption performance. This is the reason why gasoline engines are usually used in cars and racing cars, while diesel engines are used in large vehicles such as buses and trucks.

Characteristics of both fuels:

Gasoline volatilizes faster than diesel, so gasoline can enter the cylinder in the suction stroke in the state of mixture, while diesel is not volatile and does not easily form a mixture, so it can only be sprayed directly into the cylinder before the start of the power stroke.

After the diesel engine is injected with fuel, it takes a certain amount of time to burn, so it is suitable to let the fuel fully burn at a lower speed to bring high torque

Due to the high compression ratio of diesel engines, the noise generated during combustion is particularly high. And the mechanical vibrations are great. In addition, due to the high compression ratio of diesel engines, each component must withstand strong shocks.

Therefore, its structure is relatively strong, the overall volume is large, and the weight is large. Drivers and passengers also feel that the seat comfort is relatively poor. As a result, from a marketing perspective, there are relatively few opportunities for automakers to choose diesel engines as the power of their vehicles.

The manufacturing accuracy of diesel engine fuel injection devices is relatively difficult. The manufacture of some components has special requirements for domestic industrial equipment and some special steels, and some of them are also challenging for China's industrial manufacturing technology. In addition, during use, the requirements for fuel quality are also high.

If you accidentally add low-quality diesel, it may also affect the service life of the injection unit.

Due to the poor fluidity of diesel and its low volatility, spontaneous ignition (start-up) is relatively difficult to compress. This disadvantage is especially noticeable in the cold north. Although after the improvement a preheating device was installed, the low-temperature start was improved, but it was still lower than that of a gasoline engine.

Boiling point problem. The boiling point of gasoline is lower than that of diesel. The boiling point of diesel fuel is lower than that of lubricating oil.

Therefore. The combustion of diesel requires higher strength and a larger engine. If such a powerful engine is installed in a car.

First of all, it will increase the weight of the car. Larger engine, increased noise and car vibration. Reduced comfort.

The car itself requires very little power. High-power engines can lead to power mismatch.

As a result, cars will use gasoline with a lower ignition point and relatively less energy production. It can fully support the driving of the vehicle. Heavy-duty vehicles need to consider cost and power output.

Uses an engine and diesel as fuel. Its low-speed output torque is much greater than that of a gasoline engine. Diesel engines are different from gasoline engines.

Diesel engines are classified as compression ignition. There are fire points throughout the injection shrinkage space. Therefore, diesel engines can be designed with large displacements to meet high power requirements.

The diesel engine is very good, because the power of the diesel engine is relatively strong, and it is generally used in special fields and will have a feeling of overuse in cars.

The diesel engine is very good, full of power, the speed of driving is very fast, the noise of the diesel engine is very large, and the fluctuation is particularly large when starting the car, which will affect the driving feeling of the car, and the diesel car is also very unenvironmentally friendly and pollutes the air.

Such an engine is very powerful, and then it is more fuel-efficient, but the disadvantages are obvious, such as the weight is relatively large, and then the noise is relatively large when it vibrates, and the technical standard requirements are relatively high.

The reason why family cars rarely use diesel engines is because the diesel engine is relatively heavy, dismantled and noisy, and the weight is also very large, so it is relatively difficult to clean.

This is due to the fact that China feels that only military transportation and freight will use diesel for transportation, and there is also the emission standard for diesel that has not been formulated. That's why diesel engines won't be used.

Mainly because the cost of diesel is relatively high, and the exhaust gas emitted by diesel oil is higher than that of gasoline, and the horsepower of diesel is relatively large, but the car does not need so much horsepower.

Although the power of the diesel engine is relatively strong, the fuel consumption is relatively low, but the jitter is very serious, the noise is very large, and the cost is very high, which is very unsuitable.

It doesn't cost fuel at all, because the car is very small and does not need strong power, so it does not need to be equipped with a diesel engine, and there is no need to waste resources.

It is indeed more fuel-intensive, because if the power is provided by a diesel engine, it will add a lot of weight to the vehicle, which is not particularly safe.

It doesn't cost fuel at all, because the car is very small and doesn't need a lot of power, so there is no need for a diesel engine.

With the same equivalent of diesel and gasoline, the utilization rate of diesel engines will be much higher than that of gasoline engines. However, because the ignition point of diesel is much lower than that of a car, it cannot use a spark plug to ignite, and can only be ignited by compressed air, but this will form a certain noise, which is very uncomfortable to hear.

Diesel has a low ignition point and high power, which will make the vehicle noisy and shake badly, affecting the comfort of passengers. Moreover, diesel combustion is not sufficient, and the black smoke is very large, which can easily pollute the environment.

Experts say that fuel-efficient diesel engines are not environmentally friendly.

Gasoline engine with high fuel consumption, environmentally friendly.

Although the engine of a diesel car is more fuel-efficient, it will cost a lot of maintenance costs, and it will also cause serious exhaust emissions, so people are reluctant to choose diesel-burning cars.

Because the car that burns diesel is generally very wear and tear on the car, and the diesel will also affect the start of the car, although it saves money, it is not cost-effective.