Hybrid Cars

A hybrid car is always more fuel efficient than any other conventional car. In real life, hybrid cars get about 40% more miles per gallon than their conventional car equivalents.

The hybrid car that I am talking about is a vehicle that uses two or more power sources like gas power or electric power or solar power to move the vehicle. A hybrid vehicle is usually only a HEV (Hybrid Electric Vehicle) that uses gas power or internal combustion and one or two electric motors.

We all know Newton's laws of motion. The first law which is the law of Inertia says

"An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force".

This is the principle that is often used in cars. We can understand when to accelerate the car, when to keep it at a constant speed (leaving the acceleration) and when to apply breaks. We will think “Shouldn't the car stay in motion when you have got right speed?”.

The second part of the law of inertia explains this question. As there are many forces like friction, gravity, air resistance, the car eventually always comes to a stop. That is why constant fuel supply is given to the car engine so that it will generate energy for the car to move in a constant motion. On a rough surface, without accelerating, the car will automatically come to a stop. This is due to more friction than on smooth surfaces. Also, if our breaks fail, the car comes to a stop. This is due to air resistance.

Law of inertia is used in one more way. In case there is an accident that happens and the driver is not wearing a seat belt, the driver will be hurled into the air. This phenomenon happens due to law of inertia. It says that an object in motion continues to stay in motion until an unbalanced force acts upon it. When the accident happens, the driver is still in motion so he is hurled into the air due to motion.

The second law – law of momentum is also used. Depending on the total mass of the car, the car engine is accordingly designed. For e.g. if a car is of low mass, less power engine is sufficient whereas if it has a high mass, more power engine is needed.

There are many techniques/methods to improve fuel efficiency. Mainly, maintenance of car, improving aerodynamics, efficient speeds, choice of gear (torque), acceleration and deceleration, minimizing extras (like AC), fuel type or octane type.

We have to maintain our car keeping in mind the physical forces like tire pressure and friction, wheel alignment and unbalanced forces etc.

As I said earlier, the shape of the vehicle matters. Better shape of vehicle will mean less air resistance. Lesser air resistance means lesser work for the engine.

If the vehicle is in its fuel economy range, it is using the engine's power and energy most fuel efficiently. For e.g. fuel economy range for cars in India is 40 – 60 km/h.

Fuel efficiency of the car also varies because of the amount of torque created. That is why the correct gear is very important (When we change gear, torque changes).

Accelerating and decelerating very fast affects the fuel efficiency. Although it is recommended that it should be done fast, it should be smooth.

We should minimize other wants like AC. For e.g. an AC needs up to 3.7 kW of extra power which is less fuel efficiency.

There are three types of octane – lower-octane, medium-octane, higher-octane is more refined and that is why it is more fuel efficient.

The type of fuel like ethanol, octane or kerosene also matters. As ethanol is C₂H₆O, Octane is C₈H₁₈ and Kerosene is C₁₂H₂₆. As ethanol has only 2 Carbon atoms, it is more fuel efficient and vice-versa is with Kerosene. This I will explain later.

As I have mentioned earlier, hybrid cars use different types of fuels like gas, electricity, solar, wind etc. If we don't use these kind of vehicles, we won't be her (soon). As normal octane has 8 Carbon atoms, the combustion would be incomplete leaving Carbon in the form of black gas. This is much more harmful than Carbon Dioxide (CO₂). Although, electricity is more fuel efficient, it is a wastage of lots of power. That is why solar is the best power as it is renewable. Although, solar cars is going too ahead into the future, at least we should use fuels like ethanol, methanol and electricity.

From this simple graph, we can get to know a lot of things. This shows how much the use of fuel has increased- this leads to two disasters namely scarcity of fossil fuels like octane and increment of carbon, carbon monoxide and carbon dioxide in the environment. We really need to care for our environment.

Suhas

29 January 2013

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