2009
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Age old debate, which is better, diesel or petrol?
White petrol fumes and black diesel fumes are common sights in our cities. Diesel being more prevalent.
Loading ...Many will simply say, Diesel obviously, since it emits much lesser CO2 and goes more kilometers to the liter of fuel. Other’s will say Petrol, it does not give out that black smoke which to many is perceived as direct pollution.
Here are some bare facts.
First about petrol. The white or no fume from a petrol vehicle contains twice as much CO2 in it than the black one that comes out of a Diesel vehicle. In return, you get a vehicle which is low on Torque (needed to move from inertia) and high on Horse Power (needed to move faster). Different gearing helps a petrol vehicle overcome the Torque shortcomings. Apart from this the petrol motor is less noisy, has very little moving components requiring lesser maintenance, lighter, and technologically old and settled.
- Cons
- More CO2 emissions, hence bigger hole in the ozone.
- Lesser torque.
- Mostly older technology, as very little is wrong with it and it can’t get any better.
- Higher taxes in India and Europe over Diesel.
- Pros
- More horse power, so you have a much faster mark to the mile.
- Less noisy, it can be very very silent.
- Has very little moving components inside, requiring very minimal service, hence more reliable.
- Less components translate to lighter engines, and lesser weight overall for the car.
Now the Diesel, the motor our green brigade loves so much to entertain as the fuel of the future, after biogas, ethanol, biodiesel, hydrogen etc. Petrol comes a dirty last before paraffin maybe on their lists. A Diesel motor is built for the pulling power, the technology is compression based and not ‘fire in the hole’ what’s prevalent in Petrol. The Diesel motor has more Torque and hence its easier to pull larger loads with it, it has less horsepower so you really won’t be beating anyone to the finish line. It has much lesser CO2 emissions and much more particulate matter in its emission (which no one really bothers about as yet), the technology is developing and almost every other day you get a new version out. Diesels are much noisier than their Petrol counterparts and the Fuel enjoys tax benefits in most countries including India.
- Cons
- Lesser horse power, means lesser speeds as compared to petrol of similar capacity.
- Very noisy, again when compared to Petrol.
- The engine has a lot of moving parts and that generally translates into noise and maintenance in the long run (newer ones are getting better by the day).
- Still developing technology, what you buy today is outdated in the next one year.
- Pros
- Humongous amounts of Torque, to pull elephantine loads.
- Usually cheap as it gives 30% more kilometers to a liter.
- Fuel is cheaper and enjoys tax benefits, as most load carrying vehicles run on Diesel.
- Less CO2 emissions.
Now some hidden facts.
- Diesel needs 25% more oil to manufacture than Petrol. So, even though the end user runs lesser to the gas station, he is getting almost same mileage to a liter of Oil as Petrol.
- Diesels produce more particulate matter in their exhaust. Only high end expensive vehicles have particulate filters that contain most of these inside, the average road going sedan and hatch do not. These particulate matter are what we see as Smog and Dust in highly populated cities.
Quoting a more detailed website here (I am no scientist or researcher anyway):
There are three size categories of soot particles: Source: http://www.grinningplanet.com/ and http://www.ucsusa.org/
- Large soot particles (>10 microns) deposit from the air into your nose, throat, and lungs, causing coughing and irritating your throat, and are ejected from your body through sneezing, coughing, and nose blowing.
- Coarse soot particles (~10 microns) are inhaled into your windpipe and settle there, causing more irritation and more coughing.
- Fine and ultra-fine soot particles (less than 2.5 microns) are the most successful at invading your body—they’re small enough to travel deep into your lungs. Once there, these soot particles can irritate and mutate the most sensitive tissues in your lungs, your alveoli. These air sacs exchange oxygen and carbon dioxide from the air you breathe with blood in your capillaries, thus allowing your circulatory system to carry oxygen to the rest of your body. Soot particles, however, make this task more difficult because they cause inflammation and scarring of the alveoli. This also strains your heart because it must work harder to compensate for oxygen loss.
There is more.
Soot also finds other ways to harm your body, including:
- Chronic Bronchitis,
- Asthma,
- Reduced ability of respiratory system to fight infections and remove foreign particles, and
- Cancer.
Petrol engines give out particulate matter too, except that the amounts are negligible as compared to Diesels.
Originally designed to pull loads and get more miles to a full tank, Diesels are best suited for trucks, buses, long haul trains, and the highway cruiser and SUVs. In a city, it’s not as much of a Saint as it’s made out to be. In the end, you just pay higher to deplete the same amount of Natural Oil, create more particulate pollution and enjoy lesser fuel prices.
Particulate matter are not permanent pollutants like CO2, they do settle down, they just need time. But when you use a diesel in the city, you simply do not give it enough time to be ecologically viable.
Moral of the story, use it where it makes more sense, for the long haul.
Polluted Cities
Trucks on a highway, diesel delights.
Most cities now look like this.