Since the 1920sthe IC engine was established as the dominant design in automotive industry.With incremental innovation over the past 100 years, tremendous improvements instandardization, convenience, design, efficiency, energy consumption, emissionsand safety have been made; reaching an all time saturation over the past 20years with almost all manufacturers being able to deliver a new car with almostno functional mistakes even in completely new platform and engine technology conditions.This fortifies the expertise in product building capacity of the generationwith a very low rate of failure in terms of technology. The CalifornianAir resource board began the inception of the zero emission vehicles in 199025. It can be considered as the starting point that brought in the awareness towardsstronger requirements for the development of more sustainable vehicles to thegovernments.
The governments started implementing stringent emission norms thatdrove the manufacturer and the suppliers to continuously pursue innovation in ICengine technology to reduce the emission of the cars through making moreefficient engines, which also lead to vehicles with better fuel economy. Withemission norms reaching 70g/km by 2025 25 the makers are developing alternatepower trains to satisfy the emission norm using their overall portfolio. Thetechnical hurdles to reach 70g/km in a normal IC engine car make it quiteimpractical.
The Battery electric vehicle (BEV), Hybrid electric vehicle (HEV),and Fuel cell electric vehicle (FCEV) technologies are mandatory alternatives forIC engine cars to be held in portfolio to satisfy the emission targets. To identifywhich of the above alternatives is most effective for the future we need tounderstand each type in detail.4.2.1 Battery Electric Vehicle (BEV) Figure 4: Electric vehicle layout 37BEVs iscategorized as zero-emissions vehicles as it completely runs from electricenergy stored in the battery. Nearly after 60 years of Internal combustioncars, General motors developed an electric car EV1 in 1996 that was the firstmass-produced electric vehicle.
The main inspiration for this car was from theCalifornia Air Resources Board that passed a mandate for the mass productionand sales of zero emission vehicles. The EV1 product was discontinued in 2002,due to low profit reasons and all the cars sold were repossessed from thecustomers and eventually crushed 26. The poor performance of electric cars inthe market, along with high cost and unsatisfying product for both makers andcustomers led the fall of first generation of electric vehicles. With improvementin battery technology in the automotive industry in the past 2 decades a newgeneration of electric vehicles that provides greater performance emergedstarting from the company Tesla with its model roadster that used of Lithiumion battery. We are now in a situation with high performance product satisfyingboth the maker and the consumer that can be scaled with the development ofinfrastructure and supplier base to solve the constraints of cost and massiveadoption. The Battery isthe most important component of the BEV as its operation completely depends onthe electric power delivered from battery. The battery is charged from the gridor from regenerative braking where kinetic energy of the wheels are convertedto battery charge.
The battery initially was nickel-based battery technology.The technology proved to be less efficient compared to the recent lithium-ion typein terms of capacity and delivery. A Majority of carmakers are now movingtowards lithium-ion type battery technology in their electric car portfolio.Tesla roadster was first displayed to the public in 2006 that led the companyto reach a profit margin of 5% by 2009 27. The Tesla model S is a descendentof the Tesla roadster has a driving range of 435 kms on the 85D variant thatruns on lithium ion battery pack. The car is equipped to accelerate to 97 km/hin 3.2s with a battery that weighs 520 kgs 28.
This shows the dominance inperformance of electric vehicles upon comparison to traditional cars andengineering magnificence of Tesla. The car battery is delicate and dangeroushence a high level of redundancy through multiple layers of battery protectionis applied to make the car safe. The car has a cooling system to constantlykeep the lithium battery at optimum temperature.
In 2011, the Tesla received aUS government loan guarantees in collaborations with the German auto giantDaimler to produce a pure electric Sedan. 29 4.2.2 Hybrid Electric Vehicles (HEV)Figure 5: Hybrid Vehicle Layout 38HEVs combine the internalcombustion engine with one or several electric engines. In this configurationbesides the conventional fuel powering the IC engine, the car is powered byelectric energy stored in the battery that is used as an alternate powersource. The car still produces emission due to the utilization of fuel in thecar.
The main problems with electric cars are the range and time taken torecharge the batteries. This problem is completely absent in hybrid vehicles,however the equipment cost makes the car very expensive. The emission is stillpresent in the car even though reduced with the hybrid system. Toyota is thepioneer of the hybrid technology with its Prius C having 1.5L engine mated withhybrid e-CVT, the most successful hybrid car. Toyota has successfully adopted thetechnology into other cars in its product portfolio, as in the case of YarisHybrid having 1.5 L engine mated with hybrid e-CVT, Auris hybrid having 1.8 Lengine with e-CVT.
The hybrid technology is also introduced in SUVs such asRAV4Hybrid having 2.5 L engine with hybrid e-CVT. The Toyota hybrid technologyfits across engine sizes and works with good efficiency crediting the effortsfrom the research and development for incrementally innovating the batteryefficiency and hybrid technology. Nonetheless the performance of the Prius isfamously criticized for in the media. 31 General Motors realizedthe innovation of kinetic energy restoration from braking or regenerativebraking, a design to absorb energy while braking to recharge the batteries. Theenergy gained from regenerative braking is transferred to the battery that in returnpowers the electric motor. In relation to regenerative braking, Hydraulichybrid vehicles technology was developed for busses in china, the hydraulicdevice can absorb and deposit energy in the process of braking and releasingthe energy when the vehicles restart or speed up. Effectively can save morethan 30% of fuel consumption and reduce 20-27% of emission.
They are able tofunction as city buses with frequent braking and restarting. 32 Hybrid electricvehicles are categorized into three types Mild e-HEV, Full e-HEV, Plug-ine-HEV. A mild hybrid has an oversized starter motor that turns off the enginewhen the car is idling, braking or stopped. It also restarts the motorsynchronously when car is set on to motion. Afull hybrid has an electric motor that also comes with a rechargeable battery.
The electric motors can operate together with IC engine to drive the vehicle givinga greater fuel economy of up to 30% 33. The main disadvantage in this systemis the electric motor cannot function as a standalone entity as it shares the sameshaft with IC engine. The third type of HEV is the plug-in HEV. This gives theoption of external charging of the battery used in the vehicle.
Apart from thepower of combustion engine, the battery is also charged from the grid power.This design assists the vehicle to use larger power output from the batteriesthus increasing the range of the vehicle.