How Hybrid Cars Work?

Any vehicle which can be powered by two or more sources is called a Hybrid vehicle.  A very common example of the Hybrid vehicle is the Mopeds, which are powered by Engine and pedal both. Alternatively, you can think of an electric bike, which can be powered by an electric motor or can be pedalled mechanically. Other examples may have a combination of Fuel Cell and a battery, IC engine and pneumatic air or IC engine and hydraulic motor. All these Hybrid vehicles use two different power sources and combine them together to improve the performance of vehicles. Most of these systems are under research and not much information is available about them.  The most common form of a hybrid vehicle is Electric-IC Engine type Hybrid. This technology is being used extensively in cars today.

Hybrid Cars

Most of the Hybrid cars today, use Electric - Internal Combustion Engine type hybrid technology.  These cars consist of a small Internal Combustion Engine and an electric motor. The IC engine may be Diesel or Gasoline powered while the motor is battery powered.  This technology combines the benefits of the engines and the electric motors together to produce better mileage and power. These vehicles may either be propelled by the IC engine or the electric motor or both depending upon the requirements. These vehicles use  small engines which offer a variety of benefits like :

• Reduced frictional losses due to reduced piston stroke
• Reduced power and fuel wastage at idle stops
• Less noise and vibrations
• Occupies less space
• Has lesser mass

The electric motor at other hands offers advantages such as

• Zero emissions
• Negligible noise and vibrations
• Good torque at all the operating speeds
• No complex Transmission system is required for power transmission

A Hybrid car combines both these systems to complement each other. It compensates the low range of electric battery with high range IC Engines.  At other hands, the electric system helps in reducing the emissions and provides better torque at all operating speeds. A Hybrid system can easily incorporate Regenerative braking and help in preventing power wastage during the braking of the vehicle.  This system utilizes the energy of the vehicle during braking and produces electric energy to charge the batteries. Based on the configuration of their power train, they are classified into:

• Series Hybrid Cars
• Parallel Hybrid Cars

1. Series Hybrid Cars

Series  Hybrid cars consist of an engine connected in series with a generator. The power generated by the engine is used by the generator to produce electricity. This electricity is either used to run the motor or to charge a battery. The power stored in the battery can be used to propel the vehicle when the engine is not running.  These vehicles are quite similar to the electric vehicles since the final drive is provided by the electric motor only. They do not require complex transmission system since the motor speed can be varied easily by varying the current supply to it. This system allows the engine to run at its most efficient speed, irrespective of the vehicles speed. The engine may even run while the vehicle is standing on the signal. The Power generated during these idle conditions is stored in batteries for further uses. Although the series Hybrid vehicles are quite effective, they need a large number of energy conversions. Power is lost during each such conversion, decreasing the overall efficiency of this system. One more disadvantage of this system is the huge number of components required for it. This increases the overall mass of the vehicle.

2. Parallel Hybrid Cars

Parallel Hybrids have an IC engine and an electric motor connected in parallel to the transmission. These cars may either be powered by the engine or the electric motor or both depending upon the requirement.  This power transfer is controlled by a microcontroller. The microcontroller or power controller decides whether the motor and engine would operate independently or in combination with each other.   The motor is powered by a battery pack while the engine is powered by the fuel stored in the fuel tank. The motor is also used as a starting mechanism for the engine. Their motor shaft is directly connected to the transmission without any clutch. Thus shaft keeps on rotating when the vehicle is powered by the engine alone. This causes the motor to behave as an electricity generator.  The electricity thus generated is used in charging the batteries.
The electric drive is used at low speeds and city rides, as the motor provides better torque even at lower speeds. The engine can be used to power the vehicle at cruising speeds since engines are more efficient at those speeds. At cruising speeds, the excess power generated by the engine is used to charge the batteries. For high power operation both the drives can be used together. This improves the performance and mileage of the car. This system is very useful if we are driving in traffic. In traffic conditions, one requires to break the car continuously. Using electric drives can be a better option in such conditions. This will not only eliminated the pollution but also save a huge amount of fuel. This system is less complicated than the series Hybrid system. However, they require a very complex transmission system, as it needs to cater to the engine and the motor both.

3. Series-Parallel Hybrid Cars

Series-Parallel Hybrid cars have combined features of the series and parallel both the configurations. They have the IC engine, generator and electric motor connected in series like series hybrid cars. Apart from this, their engine is directly connected to the transmission system and may transfer the power directly to the wheels depending upon the requirements. These cars act as series hybrid cars at lower speeds or city commute while as parallel hybrid cars at high-speed operations. These cars are very efficient and are provides great flexibility to shift between electric and IC engine drives. However, the series-parallel hybrid system is very complex and heavy. A large number of component also make this system costly.

Degree Of Hybridization

The degree of Hybridization depends upon the level of assistance provided by the IC engine. A car powered only by the IC engine has zero degrees of Hybridization and can not be called a Hybrid car. As the level of assistance by the IC engine decreases, the level of Hybridization increases from micro to fully hybrid cars. As the level of Hybridization increases, the Electric system starts becoming more dominant and at the fully hybrid stage, it becomes capable of driving the vehicle alone. With an increasing degree of Hybridization, the mileage of the car also increases. Based on the degree of Hybridization the hybrid cars can be classified as below:

• Mild or Micro-Hybrid Cars
• Medium Hybrid Cars
• Strong or Fully Hybrid Cars
• Plug-in Hybrid Cars

1. Mild or Micro-Hybrid Cars

 These cars generally have big starter motors to assist the engine at the time of braking stopping or coasting. It allows the engine to stop during these stages and can help in restarting it quickly. The motor can spin the engine till its ideal rpm without any fuel injection. This prevents the wastage of fuel which occurs while starting a car. Mild Hybrid cars do not have a Regenerative Braking System.

2. Medium Hybrid Cars

These cars have an  IC engine as their main prime mover. The electric motor assists only when a torque boost is required. Their Electric drive can only be activated for a limited period of time and hence they need a smaller battery pack. These cars are equipped with Regenerative Braking System.

3. Strong or Fully Hybrid Cars

These cars can be propelled by engine or motor or both depending on the situation. Their Electric system is capable enough to power them independently. These cars have a large battery which can help in propelling them for a considerable period of time. They are also equipped with Regenerative Braking System.

4. Plug-In Hybrid Cars

Plug-In Hybrid cars are hybrid in real sense. All the Hybrid types discussed till now, do not have an option to charge the batteries externally. Plug-In hybrids have a much larger battery which can be charged using an external power source. These cars have Electric drive as their main driving mode while the IC engine assists during the long trips. They can be charged using household electric power and they use only electric drives for daily commutes. They are very efficient and produce very less pollution. They use 40 to 60 percent lesser fuel as compared to the normal cars.

Best Hybrid Cars In The Market

If we talk about the best hybrid cars in the market, the one name which comes to the mind is Toyota Prius. Toyota recently launched the updated Plug-In version it. The Prius Prime is a Plug-In Hybrid car having series-parallel hybrid configuration. The vehicle has a large battery pack capable enough to power the vehicle alone. This car has a range of 25 miles in electric mode while a total range of 640 miles. The charging time for its battery is 5 hours 30 minutes if plugged into household supply, while it takes only 2 hours and 30 minutes if charged using a 240 volt electric supply. Some other great hybrid cars available in the market are Ford Fusion Hybrid, Chevrolet Volt,  Honda Accord Hybrid, Toyota Camry Hybrid etc.

Hybrid Cars Pros And Cons

The greatest advantage a Hybrid car offer is a comparatively higher mileage as compared to Diesel and Petrol cars. They also produce leaser emission as compared to them. They run smoothly and quietly and offer an extended range as compared to electric cars. Now, let's talk about some shortcomings of these cars. The biggest problem with the Hybrid cars available in the market is their low Electric range. Most of the Hybrid cars available in the market have a low electric range  and their electric drive is used only to assist the engine. The second disadvantage of these cars is their high cost. Since the Hybrid technology is relatively newer, these cars are priced a little higher. Further, the use of a greater number of components makes these cars heavier. The car has to carry the weight of batteries, motor, engine, generator etc which adds a significant amount to the overall fuel cost.

This was a small article about Hybrid cars. We hope you enjoyed it. For more such interesting information do subscribe to our newsletter.