Which is fuel efficient between diesel or petrol cars?

In terms of fuel consumption, owners who have used diesel vehicles say that diesel vehicles are very fuel-efficient, while gasoline vehicles are more fuel-efficient than diesel vehicles of the same displacement, and diesel vehicles of the same level will be about 30% more fuel-efficient than gasoline vehicles.

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 ratio than the ignition gasoline engine, and the energy consumption is 45%-60% of the gasoline engine; The fuel consumption of a liter electronically controlled common rail turbocharged diesel engine is comparable to that of a liter of electronically controlled gasoline engine.

The low-speed torque of the diesel engine is greater than that of the gasoline car, and in the case of the same displacement, the diesel car will feel the power of the diesel car when starting and climbing.

Compared with gasoline vehicles with the same displacement, diesel engine CO2, CO, HC emissions are lower, NOx and particles are higher, through technical improvement, CO2 emissions are about 25% lower, NOx and particles are more than 98% lower than the old type, and the greenhouse effect of diesel engine emissions is 45% lower than that of gasoline

It should be noted that modern diesel engines must be matched with clean diesel to fully exert energy saving and emission reduction effects. In short, poor oil does increase environmental pollution.

There are several factors that must be considered when buying a diesel or petrol car.

1. In the past 7-8 years, the average annual increase in fuel ** is about 11%. In the next 5 years, oil prices should increase by an average of 11%-15%.

2. In the standard use of 100,000 kilometers in 5 years, the maintenance cost of diesel vehicles and gasoline vehicles (that is, the cost of ordinary maintenance such as oil change and filter element change) is basically the same. Some say diesel is more expensive, some say diesel is cheaper. It's hard to say, anyway, after 5 years, the total maintenance cost will vary by up to 2,000 yuan, with an average of 400 yuan per year.

3. The purchase cost of diesel vehicles is about 10,000 yuan on average. Then the price of this car is more expensive when purchasing, a one-time purchase tax, and an annual insurance cost. This cost will be 2,500 yuan more expensive in 5 years. On average, it costs 500 yuan a year.

4. Diesel vehicles and gasoline vehicles are more fuel-efficient than gasoline vehicles under various road conditions. It is generally believed that diesel vehicles are 30% more fuel-efficient than gasoline vehicles under comprehensive road conditions. In other words, if the comprehensive fuel consumption of a gasoline vehicle is 12, then the comprehensive fuel consumption of a diesel vehicle is.

Gasoline vehicles cost more fuel than diesel vehicles of the same displacement, and diesel vehicles of the same level will save about 30% of fuel compared with gasoline vehicles.

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 ratio than the ignition gasoline engine, and the energy consumption is 45%-60% of the gasoline engine; The fuel consumption of a liter electronically controlled common rail turbocharged diesel engine is comparable to that of a liter of electronically controlled gasoline engine.

Which is more fuel-efficient, diesel or gasoline, needs to be decided according to the model and displacement, not necessarily which is more fuel-efficient.

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

Hello Diesel vehicles are fuel-efficient, which are divided into single cylinder, double cylinder, four cylinder, six cylinder, eight cylinder, twelve cylinder, multi-cylinder, etc. according to the number of cylinders. The speed of the diesel engine is low, the related parts are not easy to age, the wear of parts is less than that of the gasoline engine, the life is relatively long, there is no ignition system, there are few auxiliary electrical appliances, and the failure rate of the diesel engine is much lower than that of the gasoline engine. The diesel engine is characterized by good thermal efficiency and economy, the diesel engine adopts the method of compressed air to increase the air temperature, so that the air temperature exceeds the spontaneous ignition point of the diesel, and then injects diesel, diesel spray and air mixture while igniting and combusting, and the diesel engine does not need an ignition system.

Diesel is more fuel-efficient than gasoline, and the main reason why good cars use gasoline is the sound of diesel engines.