This is probably the first question that comes to mind when you think about buying a car.
Should I buy a diesel engine car ? Should I buy a petrol engine car ? Should I buy a CNG engine car ?
The question is simple but the answer is not. In this article we I am going to share my views about the pros and cons of a Diesel Engine / Petrol Engine and CNG Engine.
[image credit : flickr]
Usually, Diesel Engine cars will run on Diesel or Bio-diesel only. The Petrol Engine car can run on petrol and can run on CNG when a suitable CNG kit is fitted on that engine.
CNG kits are not available for Diesel Engine cars as Petrol and Diesel engine have some fundamental differences which make diesel engines not-suitable for CNG. Lets see these differences in detail.
Petrol / Gasoline Engine Car :
- Petrol Engine cars are quiet as compared to the Diesel Engine cars of similar type.
- Petrol Engine cars give less fuel mileage (miles per gallon / KM per liter) when compared to diesel engine cars of similar type.
- Petrol engine cars have better acceleration and top speed compared to Diesel Engine cars.
- Petrol Engine cars have lower torque at lower engine speed when compared to a diesel engine cars. This means that a petrol car will face more difficulty climbing uphill when compared to a Diesel engine car.
- Petrol Engine cars are cheaper to maintain and initial cost is also cheaper.
- Petrol Engine is more efficient at higher speeds. This means it gives a better mileage on highway /freeway driving compared to city-driving mileage.
- Petrol Engine can be run on CNG by fitting a CNG kit to the petrol Engine of the car.
- It is more economical to buy a petrol engine car if you travel only a few miles a day, this is because the initial cost of petrol engine car is low and maintenance cost is low.
Diesel Engine Car :
- Diesel Engines cars are noisy when compared to the similar petrol engine cars.
- Diesel Engines cars are more fuel efficient compared to the petrol engine cars. Diesel Engines deliver more miles per gallon / more KM per liter of Diesel when compared to the petrol engine cars of similar type.
- Diesel Engine cars have low peak power and acceleration compared to similar capacity petrol engine car.
- Diesel Engine cars have higher torque at lower engine speed when compared to a petrol engine cars. This means that a diesel engine car can carry heavy loads uphill more easily as compared to a petrol engine car. So if you drive in a hilly terrain, you will find diesel car better compared to a petrol car.
- Diesel Engines usually have higher maintenance cost when compared to petrol engines.
- Diesel Engine cars are more fuel efficient at low engine speeds as compared to petrol engine cars. This means diesel engine car will give better fuel efficiency in city-driving conditions as compared to the petrol engine cars. This is a big advantage in countries like India where diesel is subsidized by the government and is about 30 percent cheaper than petrol. This means an effective saving of up to 50 percent on the running cost of the car because of the better fuel efficiency and cheaper fuel cost.
- Diesel Engines can not run on CNG directly by fitting a CNG kit. This is because petrol engines have spark plug and they have compression ratios which suit the CNG fuel, but the diesel engines work on compression ignition without use of spark plug and have much higher compression ratio than what is suited for CNG. Although there is some research going on to use CNG in diesel engine is some different way, but that technology is still in labs and will take some time to become feasible and available in passenger cars.
- It is more economical to buy a Diesel engine cars if you travel more than 20 miles a day or so because the high initial cost and high maintenance cost is offset by the low running cost of diesel engine car.
CNG Engine Car :
- CNG cars are usually duel fuel cars which run on both petrol/gasoline and CNG. The noise levels are same as that of a petrol car.
- CNG cars are high in fuel economy and more economical to run because of comparatively lower cost of CNG compared to petrol and diesel.
- CNG engine cars have lower power compared to similar petrol car. They are low on acceleration compared to petrol cars.
- CNG cars have low torque at low speeds, that means CNG car will find it difficult to drive uphill when compared to petrol engine car.
- CNG cars are high on fuel economy. They are cheaper to run as compared to Diesel or Petrol car.
- Maintenance cost is almost same as of a petrol engine car.
- It is economical to run a CNG car when compared to petrol only or diesel car. This is because of the low cost of CNG fuel and good fuel efficiency of CNG car. To avail this economical running, you need to spend some extra money as the initial cost is slightly higher compared to a petrol engine car. Also you have to compromise on power as CNG engine cars are slightly less powerful than petrol engine car with similar engine.
Hybrid Engine Car :
- Hybrid cars are the modern era cars which have more than one energy source. I consider these cars to be the future cars. Usually hybrid cars in the markets today run on Petrol and Battery power or Diesel and Battery Power. These cars have low noise levels when they operate on battery, otherwise the noise levels are same as that of petrol / Diesel cars.
- These cars have a very good fuel economy when compared to Diesel or Petrol or CNG. The main reason for high fuel economy is the way the car is optimized to use the Fuel and Battery in combination so as to provide best possible fuel economy. These cars are truly hi-tech and software controlled to make best use of available power.
- The power and acceleration is comparable to Petrol and Diesel cars, in fact it can be better as acceleration is really high on a battery car because of high torque and power of a battery-motor at low speeds.
- Hybrid car can go uphill with an ease if that is a diesel-battery hybrid. If the cars is a petrol-battery hybrid, it can again go uphill with ease because of the battery-motor of the car.
- Hybrid cars have a very good fuel economy because of the software control and optimization of power source usage.
- Maintenance cost and initial cost of a Hybrid car can be much higher compared to a Petrol / Diesel / CNG car because of the high cost of batteries and motors included along with the conventional engine.
- Hybrid car is very economical to run but expansive to purchase a Hybrid car at present in year 2009. I strongly believe that in a couple of years, the batteries cost will go down and with mass production, the cost of Hybrid cars will go down and these cars will be sold in large numbers because of its low running cost.
Electric Car :
- Electric cars are the cars of future, the future which is probably not-that-far. I believe that by 2015 we will see a huge growth in the number of cars which run only on batteries and motor. These cars run almost silent with very very low noise levels as compared to any other kinds of cars.
- These cars have very high fuel economy when compared to the other cars as the cost of electricity used to run the car is very low compared to the cost of Petrol / Diesel / CNG used to run the car for same distance.
- Power and acceleration of Electric depends on the motors they run on. Usually electric cars have a good acceleration and power because motors can start from zero to high speed with more ease compared to other engines.
- Electric car with a decent motor can go uphill with ease.
- Fuel economy of electric car is very high.
- Maintenance cost is usually lower compared to other kind of cars. The major part of cost of maintaining en electric car is the battery maintenance.
- Electric cars are very economical to use, but the major disadvantage as on date is that charging time of battery of an electric car can be up to few hours. Also the batteries are expansive, so the initial cost of electric car is also very high at present. Just like hybrids, there are only few fully electric cars available in market. With improvements in battery technology of cars, and with mass production, these costs can be reduced. But the biggest challenge to make electric cars good for use is to reduce the battery charging time to few minutes from few hours.
Verdict :
If you have to buy a car today for city driving and you drive only a few miles a day (less than 30 Km or 20 miles), go for a Petrol / CNG car as it is cheaper to buy and maintain.
If you drive more than 30 KM or 20 miles a day, you should consider a Diesel Engine or CNG car as the running costs will be lower.
If you have some extra bucks to shell out, you can also go for a hybrid. This will save some extra bucks in long run, but will make big hole in pocket when you buy it 😉
If you are game for some experiment and want a silent car, you can consider an electric car, though there are few options in market yet it will distinct you from the crowd. Beware that it has to be charged overnight and you can’t go on driving part a few hundred Kms in one go.
