Hybrid vehicle made urban transport system more fuel efficient with less pollution:

Hybrid vehicle made urban transport system more fuel efficient with less pollution:

At present the road transport sector is the most polluting of all. It is generating more carbon dioxide (CO2) than electricity generation or the destruction of the rainforests. There are more than 600 million cars in the world today. In developed countries this number is set to double by 2015; and elsewhere in developing countries like China and India the increase will be even faster. Although the efficiency of operation of car engines manufactured has been substantially improved by incorporating better ignition management systems and the use of improved diesel engines; the tendency is still to build vehicles with performances much higher than the road conditions allow. Growth of population in developing countries resulted in congestion and pollution which is beginning to lead to a move towards electrical traction and an expansion of public transport systems, although people try to stick to the fictional “freedom” conferred by the private car.

In this context, development of fuel-cell-powered cars running on hydrogen fuel are quite encouraging, as are hybrid vehicles that use a small, optimized gasoline or diesel engine to charge a battery. Both the systems have demonstrated a good range and able to reduce pollution quite substantially.

A. As we discussed earlier some relevant aspects of hydrogen fuel-cell vehicle; we would now discuss about few points on hybrid system of vehicles as Hybrid vehicles are taking the auto world by storm. Ever since some of the Japanese auto manufactures (Toyota and Honda) introduced their hybrid vehicles into the marketplace, the demand has exceeded the supply. Most of those who have been attracted to the new lines of hybrid vehicles do so out of regard for the environment followed by a desire to lessen this country's dependence upon foreign oil and save a few bucks on high gasoline prices.

B. A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the vehicle. Common power sources that hybrid vehicles are known today are ‘on-board rechargeable energy storage system (RESS) and a fueled power source either by internal combustion engine or by a fuel-cell’. Hybrid vehicle in general achieves greater fuel economy with lower emissions than conventional internal combustion engine vehicles. These favorable economic factors along with cleaner systems are primarily achieved by four elements of a typical hybrid design; such as, (a) Recapturing energy normally wasted during braking etc.; (b) Having significant battery storage capacity to store and reuse recaptured energy; (c) Shutting down the gasoline or diesel engine during traffic stops or while coasting or other idle periods; (d) Relying on both the gasoline (or diesel engine) and the electric motors for peak power needs, resulting in a smaller gasoline or diesel engine sized more for average usage rather than peak power usage.

These are the essential features that a hybrid vehicle has, which make it efficient in respect of fuel economy and providing emission-free environment for city traffic where there are frequent stops, coasting and idling periods. In addition, noise emissions are greatly reduced, particularly at idling and low operating speeds, in comparison to conventional gasoline or diesel powered engine vehicles. It may be important to mention here that, for continuous high speed highway use these features are much less useful in reducing emissions.

C. Another important aspect in hybrid vehicle is use of efficient battery. With the advent of new technology, more efficient batteries are made, which has made a hybrid vehicle more reliable. Today most hybrid vehicle use batteries that are made of nickel and lithium ion; these are regarded as more environmentally friendly than lead-based batteries used for most of cars today. Many of the manufactures claim that, even after use of hybrid car for about five years, no battery has been replaced. Hybrid technology for buses has seen increased attention since recent battery developments decreased battery weight significantly.

D. In short, the most advantageous factors in use of hybrid vehicles in city condition are:

(a) Improving fuel economy by (i) reducing wasted energy during idle/low output; (ii) recapturing waste energy (i.e. regenerative braking); (iii) reducing the size and power of the petrol / diesel engine, hence inefficiencies from under-utilization, by using the added power from the electric motor to compensate for the loss in peak power output from the smaller petrol / diesel engine.

(b) Durability and reliability of road transport is improved by (i) reduced wear on the gasoline engine, particularly from idling with no load; (ii) reduced wear on brakes from the regenerative braking system use; (iii) there's no definitive word on replacement costs of the batteries because they are almost never replaced.

(c) The environmental impact of hybrid vehicles has been observed more favorable than any petrol / diesel engine vehicles. (i) Reduced noise emissions resulting from substantial use of the electric motor at idling and low speeds, leading to roadway noise reduction, in comparison to conventional gasoline or diesel powered engine vehicles, resulting in beneficial noise health effects. (ii) Reduced air pollution emissions due to lower fuel consumption, leading to improved human health with regard to respiratory and other illness. Pollution reduction in urban environments may be particularly significant due to elimination of idle-at-rest.

E. Now several transport system uses hybrid technology: such as (a) Motorcycles (b) Automobiles and light trucks, currently number of manufactures in US, Japan and European countries produce hybrid electric automobiles and light trucks (c) Buses (d) Trucks (e) Military vehicles (f) Locomotives (g) Marine and other aquatic purposes.