Petrol or a diesel car? It is one of the most common dilemmas when buying a new car. To make an informed decision, you need to know the main differences between petrol and diesel vehicles. For some, petrol cars may be very suitable, and for some, diesel cars. It all depends on your requirements. To help you choose the right car, this article sheds light on the main differences between petrol and diesel cars. Read on for all the information on petrol vs diesel cars.
Which car is better petrol or diesel?
It is a very difficult question as there is no straightforward answer. Several factors must be taken into account to end the confusion between diesel cars and petrol cars. However, knowing the main differences between petrol and diesel cars will make it easier for you to choose the right car for your needs. This is what we will discuss in the following sections of this article.
The difference between petrol and diesel cars
When it comes to petrol vs diesel cars, fuel isn't the only factor that differentiates cars. There are many factors that you need to understand in order to know the overall difference between both classes of vehicles. The following parameters will allow you to better understand the difference between diesel cars and petrol cars.
Petrol car vs diesel car
These are the main differences between a petrol car and a diesel car.
| Parameters | Petrol car | Diesel car |
| Price | Petrol cars are more affordable than diesel cars. | Diesel variants are more expensive than their petrol counterparts. |
| Service and maintenance | The cost of service/maintenance is lower than diesel cars. | The cost of service/maintenance is on the higher side. |
| Fuel efficiency/mileage | Lower fuel efficiency than diesel variant. | Returns high fuel efficiency. |
| Refinement | NVH (Noise, Vibration and Harshness) levels are low. | NVH (Noise, Vibration and Harshness) levels are high. |
| Power | Good initial acceleration with linear power delivery. | Better pulling power than petrol cars due to the increased torque. |
| Eco-friendliness | Petrol engines produce less pollutant particulate matter. Hence, they are less harmful to the environment. | Diesel engines produce more pollutant particulate matter. Hence, they are more harmful to the environment. |
| Engine life | Petrol engines have a shorter lifespan due to fuel property, which wears out the engine components quicker. | Diesel engines last longer than petrol engines as the wear and tear is less pronounced due to fuel property. |
| Fuel price | Petrol is more expensive than diesel. | Diesel is comparatively cheaper than petrol. |
| Resale value | Resale value is low. | Resale value is higher than petrol cars. |
Example: To give you a better idea about petrol cars vs diesel cars, let's take the example of the Tata Nexon, which is available in two different petrol and diesel variants.
Price difference
| Tata Nexon Petrol (Base XE variant) | Tata Nexon Diesel (Base XE variant) |
| Rs. 7.29 lakhs (ex-showroom Delhi) | Rs. 8.59 lakhs (ex-showroom Delhi) |
There is a price difference of Rs. 1.3 lakhs between the petrol and diesel variants of the Tata Nexon. The higher initial cost may affect the model you choose. Please note that the price difference may vary from manufacturer to manufacturer. The above example is only shows the difference in price.
Performance
| Tata Nexon Petrol (Base XE variant) | Tata Nexon Diesel (Base XE variant) |
| Power: 118 Bhp | Power: 108 Bhp |
| Torque: 170 Nm | Torque: 260 Nm |
The petrol variant produces more power than its diesel equivalent when it comes to the performance of a petrol vs diesel car. This translates into a quick initial acceleration. On the other hand, the diesel model produces more torque, which gives it more traction than the petrol model. So the initial acceleration may not be as quick as a gas engine, but it has a big impact at the top end of the RPM (revolutions per minute).
Fuel economy
| Tata Nexon Petrol (Base XE variant) | Tata Nexon Diesel (Base XE variant) |
| 17 kmpl (As per ARAI) | 21.5 kmpl (As per ARAI) |
Diesel engines are more fuel efficient than petrol engines. This factor can play an important role when choosing between a type of petrol or diesel vehicle. However, remember that a diesel engine requires more maintenance than a petrol engine.
The difference between petrol and diesel engine
The engine is the heart of the car. In general, this is the first thing you look for when you take a look at the specifications of a car. The type of fuel is the first deciding factor before shortlisting cars when buying a new car.
Petrol vs Diesel Engine
| Parameters | Petrol engine | Diesel engine |
| Working principle | Otto cycle | Diesel cycle |
| Air-fuel mixture | Air and fuel are mixed before the compression. | The air and fuel are mixed inside the combustion chamber. |
| Ignition of fuel | Fuel is ignited by a spark produced via spark plugs. | Fuel is ignited by the hot compressed air. |
| Compression ratio | Low | High |
| Power | Lower than a diesel engine. | Higher than a petrol engine. |
| Fuel | High volatile fuels such as petrol. | Low volatile fuels such as diesel. |
| Application | Light vehicles such as two-wheelers and cars. | SUVs and heavy vehicles such as trucks and buses. |
| Fuel economy | Low | High |
| Maintenance cost | Low | High |
Both petrol and diesel engines are IC (internal combustion) engines. However, there are many differences when it comes to the working mechanism of both motors. Details of both motors are shown below.
Petrol engine
Refer to the points below to understand how a petrol engine works.
- A petrol engine works on the Otto cycle.
- Contains a spark ignition system to ignite the fuel.
- Works with volatile fuels such as petrol.
- Four-stroke cycle petrol engine: intake, compression, combustion and exhaust.
- During the intake stroke, the fuel-air mixture is drawn into the combustion chamber through the intake valve.
- The piston compresses the fuel/air mixture during the compression stroke.
- On the combustion stroke, the air-fuel mixture is ignited by a spark produced by the spark plug. Combustion generates energy. Therefore, it is also called a power stroke.
- Exhaust gases are expelled from the combustion chamber through the exhaust valve during the exhaust stroke.
Diesel engine
The following points explain how a diesel engine works.
- Diesel engine works on a diesel cycle.
- Works with pressure ignition system.
- It has a four-stroke cycle: intake/suction, compression, power and exhaust.
- On the intake stroke, air enters the combustion chamber through the intake valve.
- On the compression stroke, the air is compressed by the piston. Due to pressure, the air temperature rises.
- Then, on the power stroke, diesel fuel is sprayed into the combustion chamber through the injectors. The fuel is ignited with hot compressed air and pushes the piston.
- Exhaust gases are removed from the combustion chamber through the exhaust valve. It's called an exhaust stroke.
Pros and cons of a petrol car
Below are the advantages of petrol cars
- Their prices are more reasonable than their diesel counterparts.
- Various options are available in different types of petrol, from small hatchbacks to SUVs (Sports Utility Vehicles).
- Petrol engines provide better initial acceleration. Therefore, they are more sensitive than diesel engines.
- NVH levels are well contained.
- The cost of its maintenance is lower than that of diesel cars.
- Petrol cars work better in bad weather conditions.
These are some of the disadvantages of petrol cars.
- Less fuel efficient compared to diesel cars.
- Petrol engines cannot be used in heavy vehicles.
- Low resale value in the used car market.
- The cost of gasoline is high compared to diesel.
Pros and cons of diesel cars
These are some of the advantages of diesel cars.
- Low operating cost due to better fuel economy than Petrol cars.
- Diesel cars produce more torque.
- Longer engine life.
- High value orders for resale in the used car market.
- Large SUVs are only available with diesel engines due to the high torque they produce.
- Better performance in high altitude areas where there are no specific air-fuel ratio requirements.
Here are the disadvantages of diesel cars.
- More expensive than Petrol cars.
- Small cars such as hatchbacks may not be available in diesel types.
- High levels of NVH.
- The maintenance cost is higher than that of petrol cars. Also, diesel engine parts require a higher price.
- Diesel engines produce less power and are somewhat slower than Petrol engines.
- Diesel engines produce more harmful gases than petrol engines.
- It is difficult to start a diesel car in very cold weather.
Petrol vs diesel: fuel price
One of the critical factors to consider when choosing between a diesel or petrol car is the price of fuel. Diesel is relatively cheaper than petrol. Hence, if we look at the cost of fuel, diesel is the best option. However, a diesel car comes at a high price and maintenance costs are also high. Therefore, you need to make an informed decision based on your requirements.
Diesel vs petrol price
The below table denotes the price of diesel vs petrol.
| Diesel | Petrol |
| Rs. 88.62 per litre (Delhi) | Rs. 101.19 per litre (Delhi) |
Petrol vs Diesel Car Running Cost Calculator
Calculating the cost of running a petrol or diesel car is quite simple. However, there are several factors to consider, such as driving distance, fuel efficiency, and fuel price.
Below is an example of operating cost calculation for a Tata Nexon SUV, which is available in petrol and diesel variants. Please note that we have taken into account the default ARAI driving distance and fuel economy figures.
Tata Nexon XE Price (ex-showroom Delhi)
Petrol: Rs. 7.29 lakhs
Diesel: Rs. 8.59 lakhs
Fuel economy for the Tata Nexon XE variant
Petrol: 17 kilometers per liter Diesel: 21.5 cubic kilometers
Petrol vs Diesel Price in Delhi as of Sep 21, 2021
Petrol: Rs. 101.19/L
Diesel: Rs. 88.62/l
Assuming a car travels 1,000 kilometers per month, the cost of operating the variable petrol and diesel variants is as follows.
Petrol variant (driving distance/fuel economy x fuel price): Rs. 5952
Diesel variant (driving distance/fuel economy x fuel price): Rs. 4121
Price difference: Rs. 1,831
Now, if you buy a diesel model, the time needed to recover Rs. 1.30 lakhs paid for the diesel variant for almost six years. However, the calculation changes as the monthly driving distance increases. This account will give you an idea of the best option for your driving needs. The diesel option makes more sense if the driving distance is higher.
Best Selling Petrol and Diesel Cars in India
Below is the list of the best-selling petrol cars in India
- Maruti Alto
- Maruti Swift
- Maruti Baleno
- Maruti Wagon R
- Maruti Dzire
Here is the list of the best-selling diesel cars in India
- Hyundai Creta
- Toyota Innova Cresta
- Mahindra Bolero
- Mahindra Scorpio
- Kia Sonet
The verdict
So which car is better, petrol or diesel? Choosing between a petrol and a diesel car can be a difficult task. But with a clear understanding of your requirements, you can make the right choice. Diesel cars have the advantage due to fuel economy and low fuel cost. However, servicing and maintaining diesel cars can cost you a lot.
So don't make your choice based solely on the vehicle's fuel efficiency. Instead, buy a car after calculating the approximate cost of operation and considering ownership. If you want to have a car for a long time and the average daily driving distance is about 80-100 km, a diesel car is the best choice. Conversely, if the driving distance is less and you don't intend to have the car for more than 3-4 years, then a gas-powered car makes more sense.
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