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Evolution of Hybrid Cars

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1. Introduction:

The European government is trying to explore market and infrastructure issues related to an innovative, narrow-lane commuter car under development by a major auto manufacturer. In sufficient numbers, this vehicle offers an opportunity to increase the capacity of the existing transportation infrastructure, reduce the state's dependence on petroleum and lower emissions of air pollutants.

The commuter car is an innovative vehicle concept that is comparable to a motorcycle in size but offers advantages similar to an automobile in comfort, utility and safety. Depending upon the customer requirements a commuter car can be designed either a three-wheel or four-wheel. Passenger emenities similar to those available in standard automobiles, including climate control systems high quality stereo systems, and passenger restraint devices, would be available as options in this commuter car. This car offers several advantages that are inherent in the design.

This report presents the product specifications which are going to be designed through different software's, material selection and the market research analysis.

2. Evolution of Hybrid Cars:

A hybrid automobile is a means of transportation employing two power sources; it uses a Re-chargeable energy storage system found on board and a fuelled power source as the vehicle's ambition. The hybrid car pollutes much less and uses not as much fuel.

Back in 1899, Ferdinand Porsche have developed and led the way to the initial working hybrid-electric vehicle. On the other hand, there was no key vehicle manufacturer who invested in the hybrid idea and mass produced hybrid cars until the late twentieth century. The hybrid technology was mainly utilized in developing diesel-electric submarines in the course of that interim period. Yet, the submarines major objective was to conserve oxygen as opposed to spend less fuel. Throughout the later years, submarines have evolved and have begun using the nuclear power as an alternative for diesel.

During the 1990's, the Toyota Prius plus the Honda Insight were the very first profitable hybrid cars available in the market. It was two of the pioneers inside the hybrid auto idea which virtually adjusted the way the world considers cars. An idealistic inventor, Victor Wouk, manufactured a hybrid electric and gas car that siphoned fuel at half the quantity as practically all the other cars becoming built then. He built the hybrid car thirty years before the Toyota Prius got the attention of the U.S. as an energy- uneasy nation. And now the striking capabilities of the creation of Wouk, the hybrid cars, are now able to be an incredibly great support relating to less gas ingestion and less air pollution. Wouk and Rosen put up a start up business particularly to develop their hybrid car thought and made it easy to be on the market and be utilized as a regular automobile that belched less harmful vapors than up-to-date vehicles.

The Prius Ever since the Toyota Prius, fuel efficient car was released on the market; it has been able to remain as the premier option of hybrid cars available. It is a fact that old hybrid cars looks more like an alien automobile and cost much more than the conventional car. Yet, because of the most up-to-date technologies installed in newer versions of hybrid cars, it looks extra like a conventional car and is far less expensive than its predecessors. It is a fact that hybrid cars these days look a whole lot like conventional cars. The Civic Hybrid can get 50 miles in mere 1 gallon of gasoline.

During the year 2004, Ford has developed and introduced the initial hybrid SUV that is the Ford Escape Hybrid. A year later, Toyota also introduced their line of hybrid SUV called the Highlander Hybrid. Because of the increasing requirement for hybrid cars, other auto manufacturers are now following the footsteps of the other companies who already brought out a version of their hybrid car on the market. As an example, Nissan is now going to develop and introduce a hybrid version of the Nissan Altima. Presently, over 300,000 hybrid cars are running on American roads wherein 95 percent of them are Japanese made. The hybrid vehicles are really quite distinct technologies that can both reduce financial outlay and our environment.

3. WORKING PRINCIPLE OF HYBRID CARS:

A hybrid is anything that uses two or more sources directly or indirectly to provide propulsion. Two power sources set up in a hybrid car in different ways. It has a fuel tank, which supplies gasoline to the engine and set of batteries that supplies power to an electric motor. The engine and the electric motor together can turn the transmission at identical time, and the transmission then turns the road wheels as shown in the figure1.

The different ways in which the power sources establish in car are describe as follows:

  1. Series Hybrid Cars.
  2. Parallel Hybrid Cars.
  3. Series-Parallel Cars.

3.1 Series Hybrid Cars:

The simplest of hybrid configuration is the Series Hybrid Car. In a series hybrid, the electric motor is the only resource of providing power to get wheels turning. The motor receives electric power from either the battery pack or from a generator run by a gasoline engine. The Battery pack is recharged by both the engine/generator and regenerative braking. The engine in a series drive train is typically smaller because it only meets the average driving power demands. The battery pack in these Hybrid cars generally more powerful than the one in parallel hybrid providing remaining peak driving power needs. Series hybrids are more expensive than parallel hybrids as the larger battery and motor with the generator add to the cost.

While the engine in a conventional vehicle is forced to operate inefficiently to satisfy varying power demands of stop-and-go driving, series hybrids perform at their best in such conditions, as the gasoline engine in a series hybrid is not coupled to the wheels. This means the engine is no longer subject to the widely varying power demands experienced in stop-and-go driving and can instead operate in a narrow power range at near optimum efficiency , which eliminates the need for a complicated multi-speed transmission and clutch. Because series drive trains perform best in stop-and-go driving are primarily being considered for buses and other urban work vehicles. The figure below shows the process of series hybrid car

3.2 Parallel Hybrid Car:

In parallel hybrid electric vehicle, the wheels are driven by the power generated from both the engine and the electric motor. The addition of computer controls and a transmission allow these components to work together. Parallel hybrids use a smaller battery pack and mainly depend on regenerative braking to keep it recharged. However, when power demands are low, parallel hybrids also utilize the drive motor as a generator for supplemental recharging, same as that of an alternator in conventional cars.

In this setup the wheels are directly connected to the engine, which eliminates the inefficiency of converting mechanical power to electricity and back, which makes these hybrids quite efficient on the highway. The same direct connection between the engine and the wheels that increases highway efficiency compared to a series hybrid does reduce, but not eliminate, the city driving efficiency benefits. The figure below shows the process of parallel hybrid cars

3.3 Series-Parallel Hybrid Car:

This drive train merges the advantages and complications of the parallel and series drive trains. As a result of combining the two designs, the engine can both drive the wheels directly (as in the parallel drive train) and be effectively disconnected from the wheels so that only the electric motor powers the wheels (as in the series drive train). Therefore, the engine operates at near optimum efficiency more often because of this dual drive train. At lower speeds it operates more as a series vehicle, while at high speeds, where the series drive train is less efficient, the engine takes over and energy loss is minimized. This system is expensive than that of a pure parallel hybrid since it needs a generator, a larger battery pack, and more computing power to control the dual system. However, the series/parallel drive train has the potential to perform better than either of the systems alone. The figure below shows the series-parallel hybrid process.

4. Project Planning:

As can be seen in figure 4, the project plan includes the timescale of the project as a whole, from the beginning to the end. It outlines the various stages of the project highlighting the objectives and deliverables of each part of the project. It also defines the deadlines of each stage so as to assure that the project runs as per the schedule desired. However, it has to be taken into account that all the real world situations cannot be accounted for and hence, a safety period of appropriate measure has to be incorporated into each stage or at the end of the project. This assures that the deadlines will be met even in the event of unforeseeable circumstances.

The project plan in itself is not a sufficient tool to manage a project of this magnitude. Hence, various other management tools were used during the course of this project to facilitate in the timely completion and effective management of the time and resources available to the team as a whole as well as, as individuals. These management tools include Gantt chart, Quality Function Deployment (QFD), Critical Path Analysis (CPA), Program Evaluation and Review (PERT), SWOT Analysis etc.

4.1 GANTT CHART:

Gantt chart is a bar chart known after Henry Gantt who designed his chart in the beginning of 20th century. It shows a very clear and easily explicable manner of the project structure in terms of time and individual tasks and subtasks. The project time schedule was visualized and optimized using Gantt chart.

In this case, the CHV project was divided into eleven main tasks: 1. market research, 2. technical research, 3. target setting, 4. concept development, 5. concept finalization, 6. further concept development, 7. management analysis and 8. Report. These tasks, in certain cases, are subdivided into subtasks, usually assigned to a particular group member responsible for that part. Name(s) of the member(s) working on an individual task are written near the blue bar, which represents the time duration of the task. The project Gantt Chart is shown in APPENDIX-1:

4.2 Critical Path Analysis:

Critical Path Analysis (CPA) is a management tool that analyzes all the tasks required for completing the project, paying specific attention to the time required for the completion of each activity. It is used to formulate, schedule and manage the various milestones or activities in the project. It was developed in the 1950's to control large defiance projects and have been used routinely from then (mindtools.com).The critical path analysis for the CHV project was useful in:-

  1. Identifying all major activities requiring time.
  2. Time required for each activity was estimated and the overall project plan.
  3. Logical sequencing of these activities.

For drawing the CPA first step was listing out the major activity. The next step is to sequence the activities into a logical order based on when it must or is most likely to occur i.e. certain activities will logically proceed after an activity while certain activities will be taking place parallel to each other. After sequencing, the time period required to complete each activity was determined. Time is represented in most networks as days. The time period for each activity was calculated taking into account the suggestions made by group members and considering other factors such as how many people will be working on each task, how many working days etc. As can be seen in Table 1, the findings are recorded in table format for easy look. The table also records the sequence of the activities as series, meaning occurs after another activity, and parallel, meaning occurring along with another activity. The dependence of an activity is also mentioned in the table.

Process

Title

Duration (days)

Depend on

1

Project planning

3

-

2

Product design specification

6

After start 2days

3

Material selection

6

2

4

2D detail drawing of unique components

16

3

5

Vehicle chassis design

7

4

6

Analysis of chassis

4

5

7

Description of operation modes

5

6

8

Assembly of all unique components

6

7

9

Test run

3

8

10

Final run

3

9

11

Documentation

4

10

Table1:

From the table 1 below, a chart is drawn in Figure 5 which represents the activities in circles and the time taken to complete an activity is stated on the arrow joining two activities.

From the above CPA this project requires 62 minimum numbers of days for the completion of the project.

4.3 SWOT ANALYSIS

SWOT analysis is a planning method that analysis the strengths, weakness, opportunities and threats for a project. SWOT is a model that helps in assessment of a firm of what it can and cannot do along with the potential opportunities and threats. In SWOT analysis the information is separated into internal and external issues and each issue is addressed. SWOT analysis is useful in helping the group in meeting its objectives and also the obstacles to overcome to meet the desired result. The SWOT analysis carried out by the group is shown below, in APPENDIX-2..

The analysis was done, the strength and weakness of the group were put down along with its opportunities available for CHV was discussed and the barriers which could prove serious for the CHV project were taken into consideration . The ways to minimize the threats were also discussed with the help of group..

4.4 3P's:

Similar as other analysis techniques such as QFD or DFMEA, 3Ps is a management aiding method designed to help designers make better plans. The major function of 3Ps is to find disadvantages faced during a specific time for the period of the project, then to workout them. So 3P is the combination of Progress against Plan, Problems with the Progress and Plan to solve Problems.

All team members knew the weakness of this project by making 3Ps and the main problems in it have to be solved. It is very useful method because it shows the current conditions of the project; especially the direction designers should pay more concentration. The disadvantage of the project is known at the beginning and makes people think about it.

5. Market research:

The first step of the project, as per the Gantt chart and the project planning was market research. This includes researching on the current vehicles that are available in the market and are due to be available within the next 3-6 months. Also to be considered is the market evaluation i.e. what types of vehicles are the customers most inclined to buy and what is the most desirable from CVs.

As the project specification includes that the vehicle is to be a family hatchback powered by an electric battery and IC engine, the “Chevrolet Volt” or the “Honda Insight” cars were taken as bench marking. The market research results are shown in Table 5.

Chevrolet Volt (carwear.com)

Honda Insight (Honda.co.uk)

Manufacturer:- Chevrolet

Manufacturer:- Honda

Body work:-

Body work:-

Type- Hatchback

Type- Hatchback

Number of Doors-5

Number of Doors-5

Type of Drive- Front wheel

Type of Drive- Front Wheel Drive

Steering- Rack &Pinion PAS

Steering- Rack &Pinion PAS

Transmission Type-1 speed direct drive

Transmission Type-1 speed automatic

Engine Specification :-

Engine Specification :-

Cylinders- Inline 3

Cylinders- 4

Displacement- 1398 cc

Displacement- 1339

Maximum Power-3200 rpm

Maximum Power-5800 RPM

Torque-236/320

Torque-121

Dimension & Weight:-

Dimension & Weight:-

Wheel base-105.7 in

Wheel base-107.5 IN

Width-70.4 in

Width-2029 mm

Height-56.6 in

Height-1425 mm

Length-177.1 in

Length-4396 mm

Curb Weight-3781 lbs

Curb Weight- 1240 kgs

Suspension:-

Suspension:-

Front:-McPherson Strut

Front: McPherson strut

Rear:-Torsion bar

Rear:-Independent suspension

Brakes:- (F /R)- Electro hydraulic power assisted

Brakes:- (F /R)- Ventilated Disc Brakes

Performance:-

Performance:-

0-60 mph- 8.5 sec

0-62 mph-12.5

0-100 mph-11.5 sec

0-100 mph-16.5

Top Speed-120 miles

Top Speed-113 miles

Aerodynamics:-

Aerodynamics:-

Drag Coefficient-0.287

Drag Coefficient-0.360

Wheel &Tyres:-

Wheel &Tyres:-

Wheel Front-17X7 .in

Wheel Front-15X5 1/2J

Wheel Rear-17X7.in

Wheel Rear-15X5 1/2J

Tyres Front-P 215/55r/17

Tyres Front-175/65 R15

Tyre Rears -P215/55r/17

Tyre Rears -175/65 R15

Safety Features :-

Safety Features :-

Airbags- Driver & passenger -Y

Airbags-Driver & passenger -Y

Driver & Front passenger side -Y

Driver & Front passenger side -Y

ABS- Y

ABS- Y

ESP- Y

ESP- Y

EBA- Y

EBA- Y

EBD- Y

EBD- Y

Power Steering-Y

Power Steering-Y

Auto Climate control System-y

Automatic Climate control System-Y

5.1 Comparison of vehicles using different sources as energy:

l. Petrol car: A journey of 68 miles each day consumes 2.5 gallons of fuel and takes 2 hours.

Amount of energy in fuel = 5.14 x 108 joules

Thermal power = 71.3 kW

Mechanical power = 20 kW average

Efficiency = 28%

2. Battery electric car as secondary transport.

Power station efficiency 40%

Electric car efficiency 80%

OVERALL 32%

CONCLUSION: Pollution is moved from car to power station. There is only an environmental return if the car's performance is sacrificed or the power station is non-thermal and range/performance is limited.

3. Fuel-cell electric car as primary transport.

Hydrocarbon to hydrogen conversion 75%

Fuel-cell hydrogen to electricity 58%

Electricity to mechanical power 87%

OVERALL 38% (potential for 41% in 10 years)

CONCLUSION: Pollution reduced by 88%; fuel consumption is 60% of petrol vehicle and

Performance /range are as petrol vehicle.

4. Hybrid car as primary transport.

Hydrocarbon to electricity

Via lean burn petrol engine 45%

Electricity to mechanical power 90%

OVERALL 40.5%

CONCLUSION: Pollution reduced by 70% and fuel consumption is 70% of petrol vehicle with performance/range as the petrol vehicle.

So from the above comparison Hybrid car is the best transport CV which reduces the pollution and fuel consumption with good performance.

6. Technical Research:

The next step is the technical research. It includes researching the technologies currently available in the market for the major components of the CHV. The major components of the CHV were divided into several components as below

  • Batteries.
  • Motors and Controllers.
  • Aerodynamic.
  • Regenerative braking.
  • IC Engine.
  • Transmission and
  • Safety and homologation.

6.1 BATTERIES:

The battery package is an essential element of an electric vehicle. Its electrical properties determines the vehicle driving range, while its physical properties must be consider during suspension design, vehicle architecture, etc. According to Larminie and Lowry (2003), batteries are the component with highest cost, weight and volume.

Generally, a battery consists of two or more electric cells, which are joined together and generate DC electricity. There are several parameters describing the properties of a battery such as internal resistance, charge capacity, energy stored [Wh] or specific energy [Wh.kg-1]. Service temperature is a very important factor influencing the battery performance.

Several different types of batteries were identified during research (Larminie and Lowry 2003):

Lead-acid batteries:

This is widely used with main constituents - lead, sulphuric acid, plastic container which are available at low cost. However, lead acid batteries have a very low specific energy. Therefore, a battery with sufficient capacity using this technology would be very heavy. As a result, lead acid batteries are used in low-cost and low-range electric vehicles.

Nickel-cadmium batteries:

These batteries have a specific energy nearly twice that of lead-acid batteries. They possess a low self-discharge capability and are able to work in wide range of temperature (-40°C to 80°C). The presence cadmium is considered as a major drawback. Nickel-cadmium (NiCd) batteries were used in electric cars.

Nickel-metal hydride batteries:

As of the abbreviation NiMH, these are used in hybrid vehicles. The main principle is as like that of nickel-cadmium batteries, but the negative electrode uses hydrogen absorbed in metal hydride instead of cadmium. In addition NiMH batteries have higher specific energy. But, their self-discharge rate is relatively high which is ten times to that of NiCd. Since the reaction running in the battery is exothermic, a NiMH battery package must be cooled.

Sodium-based batteries:

In spite of high specific energy, sodium-based batteries have serious disadvantages that exclude it from commercial use of hybrid vehicle. Its operating temperature lies in the range of 300-350°C. Once the battery is cooled down, it must be slowly reheated before operation and this process can take up to 24 hours. Besides, keeping the battery at its required temperature requires approximately 100 W of power.

Lithium batteries:

Lithium-ion batteries (Li-ion) are the latest stage in battery development providing the best performance for electric vehicles. They have a high specific energy and consequently a very low overall weight. This type of battery is used by the most recent electric vehicle available in the market (e.g. Nissan Leaf, Peugeot iOn, Tesla Roadster). The crucial disadvantage of Li-ion batteries is their high cost.

Battery type

Specific energy

[Wh.kg-1]

Specific power

[W.kg-1]

Cost Coefficient

Lead-acid

30

250

0.5

NiCd

50

150

1.5

NiMH

65

200

2.0

Zebra

100

150

2.0

Li-ion

90

300

10

Table 6: Battery comparison table

Assumed input data

ICE vehicle consumption: 4 l/100 km of diesel fuel (Volkswagen 2010)

Diesel fuel specific energy: 40 kWh/kg

Diesel fuel density: 0.832 kg/l

ICE vehicle fuel → wheels efficiency: 10%

EV vehicle fuel → wheels efficiency: 70%

According to the input data, the required capacity of the battery pack is from 46 kWh to 61 kWh. According to specific energy of individual battery type the battery weight can be estimated (Table 7).

For the desired range, lead acid batteries are far too heavy to be applied in a family hatchback. However, they can be considered as a cheap alternative for a low-range electric vehicle.

Battery type

Specific energy

Battery pack weight

150 miles

200 miles

Lead acid

30 Wh/kg

1533 kg

2033 kg

NiMH

65 Wh/kg

708 kg

938 kg

Li-Ion

90 Wh/kg

511 kg

678 kg

Table 7:Battery Comparison according to range

According to the table above, lithium-ion batteries are the most suitable option. If the latest technology is used (Nissan Leaf's laminated Li-Ion batteries), specific energy can reach 140 kW/h (Weissler 2010), and thus the battery weight can be further reduced. In addition to this, the latest development shows a good potential in increasing Li-ion battery performance by means of nanotechnology. Furthermore, according to various prediction e.g. by The Boston Consulting Group (2010), the battery cost are about to decrease with the increase of production volume and it can be more than 50 % in the year 2020.

6.2 MOTORS AND CONTROLLERS:

Motors is considered to be one of the main part of the electric vehicle .In a pure electric vehicle the motor provides the required torque directly to the wheels. However, the motor rotates at constant speed, so to vary the speed of the vehicle a potentiometer needs to be attached. The speed control of the vehicle is made possible by DC or AC (inverters) controllers. The accelerator pedal is attached to a potentiometer (variable resistor) which is further attached to the DC or AC controllers. The force on the accelerator pedal is directly proportional to the current delivered to the controller. Depending on the current supplied, the controller delivers power to the motor. The working of DC controller varies with an AC controller. For selecting a motor the main features that are important for an electric vehicle are good efficiency, high torque, low maintenance, moderate cost and easy to control. Figure 4 shows the basic layout of the motor and controller in an electric vehicle.

The three motors considered for the concept were:-

  1. AC Synchronous Motor.
  2. DC Brushless Motor
  3. AC Induction Motor

AC 3 synchronous motor is the latest type of motor used in electric vehicle. The main characteristic of AC 3 synchronous motor is that the motor runs at synchronous speed i.e. the field winding locks with the rotating magnetic fields and rotates along with it. The AC 3 synchronous motors has many advantages .Usually the AC induction motor works at lagging power factor but the AC 3 synchronous motor works at leading power factor which means improved efficiency and reduction in voltage drop .Accurate speed control is possible which makes synchronous motors an ideal choice .Synchronous motors have speed/torque characteristics which are ideally suited for direct drive of loads. A smooth the torque curve results in better performance of the vehicle. It has good heat dissipation and overloading capacity .The absence of magnets also reduce the cost of maintenance. Regeneration of energy is easily possible in an AC 3 synchronous motor by reversing the current. AC 3 synchronous motors has certain disadvantages such as it is not a self starting motor i.e. a separate motor (pony motor) is required to drive it till it reaches synchronization. Since it is relatively a new technology the price of the motor is comparatively higher.

DC Brushless Motor or BLDC is the most common motor used in hybrid vehicles. A BLDC motor is similar to AC 3 synchronous motor. It has got good torque characteristics and also absence of slip. The heat dissipation and overloading characteristics is commendable for a BLDC motor. But BLDC motor is considered to be less efficient than the other three motors because of many factors. It has many disadvantages such as BLDC motors consists of magnets which incur in the cost of the motor. It is usually high on maintenance cost because the commutator assembly is susceptible to mechanical wear. Expensive and complex power electronics used for controlling the motor also increases the cost of maintenance of the motor.

AC induction motor is the most common motor used till date for pure electric vehicles. Their robustness, low cost and freedom from control make AC induction motor preferable for electric vehicles. Precise speed regulation can be achieved in an AC induction motor and is also much cheaper to produce. It is self starting and no maintenance is required for the motor .Regenerative braking is possible which improves the range of the vehicle. But compared to AC 3 synchronous motor it has poor torque characteristics and runs at less than synchronous speed i.e. the efficiency of AC induction motor is less compared to a AC 3 synchronous motor.

AC 3 synchronous motor is the best bet compared to the other two motors. It has mechanical advantage over the other two and also higher efficiency .Considering that the car would go for production in a few years time the AC induction motor would not be a dated technology. But the drawback is that it would be expensive but mass production is expected to reduce costs and it hence would become a more feasible option.

Hybrid engine and transmission:

Hybrid engine takes the advantage of efficient fuel engine couple with high output electric motor. The computer operation system of the engine can choose the most efficient power source for the working depending on vehicles situation. The motor which is used in hybrid works as generator to generate the electricity which charges the battery. Regenerate braking principle is usually applied, for charging the battery.

Hybrid car also have 4-5 speed style of transmission same as to that of conventional cars. The torque convertor can be replaced by electrically controlled. The transmission of hybrid engine usually has three modes:

Power mode

The power mode which is used to force the car forward. To produce the most power for situation of the car such as take off and acceleration a motor timing is controlled by computer system.

Free-Wheel Mode

This mode is used while the vehicle use internal combustion engine for its working.

Braking Mode

While braking is applied Braking Mode is used. The car is slowed by the cursing of motor that work as generator and produce the electric power.

6.3 REGENERATIVE BRAKING:

When brakes are applied in a vehicle, the kinetic energy of the vehicle is converted to heat and noise energy. This energy is essentially wasted as these forms of energy are no longer used by the vehicle for operating. Regenerative braking looks to use the kinetic energy of the vehicle to drive the vehicle, at least in part. For a traditional vehicle driving on urban roads, the road condition is very complex. The driver has to be careful and applies the brakes numerous times, as and when necessary, such as for traffic lights or crosswalk. A lot of energy is wasted under these conditions and become heat between axes and brake lining (Larminie and Lowry 2003).

It is estimated that regenerative braking systems currently operate at 31.3% efficiency; however, the actual efficiency depends on numerous factors, such as the state of charge of the battery, how many wheels are equipped to use the regenerative braking system, and whether the topology used is parallel or serial in nature (Larminie and Lowry 2003). In spite of above complex conditions, the amount of energy saved by regenerative braking is attractive.

In the current regenerative braking technology, there are two main methods to recycle kinetic energy. The main difference between the two is whilst one method does not change the form of kinetic energy and the other does.

In this regenerative braking, when the electroni braking system is activated, the electric motor is shifted into reverse mode. This creates resistance to slow the vehicle. The system also then acts as a dynamo, generating electrical energy that is stored for reuse. The method which does not change the form of energy is based on a high speed flywheel. When the driver applies the brakes of the vehicle, some of the braking energy will drive a heavy flywheel and be stored into its rotation. Then this rolling flywheel will speed up the vehicle under acceleration.

The advantage of this method is low energy waste. It is suitable for high speed vehicle, such as racing car. Formula 1 has conquered the sealing difficulty of the vacuum container of the high speed flywheel and used this technology to accelerate their cars. Store rolling energy into a rolling flywheel thereby cutting the waste of conversion energy forms, however this technology is too costly to use on civil vehicles and not very efficient for low speed vehicles (Formula One Administration Ltd n.d.).

The other method converts and stores the kinetic energy from braking into other forms and use the energy when it is necessary. The most efficient storage form is hydraulic fluid. The mechanism is attached to the driveshaft of the vehicle and when brakes are applied feeds energy into hydraulic accumulators and is stored as hydraulic fluid under great pressure. The energy is then released again into the drive shaft when the vehicle is accelerating. This system is claimed to withhold up to 42.7% of the energy otherwise wasted in braking. The other storage form is to convert the kinetic energy back into electricity and store them into the battery. In this system, braking is accomplished by switching motors to act as generators that convert motion into electricity instead of electricity into motion.

Comparing above methods, storing energy into the battery is the most suitable for group design. This method does not need the complex technology as Formula 1, it is simple to operate and does not have too many accessories as the hydraulic one. Because the traditional friction-based brakes must also be provided to be used when rapid, powerful braking is required, the efficient of regenerative braking will not be as high as those ratio this report mentioned above. Thus the cost of this system is the main point people need to consider.

Besides regenerative braking, the vehicle can be recharged by other available energy, such as solar and wind power. The power of raw sunshine at midday on a cloudless day is 1000W per square meter. Combine with conditions of sunlight density, cloud and wobble season, the average raw power of sunshine per square meter of flat ground is roughly 100 W/m2. The efficiency of photovoltaic panel is about 10% to 20%. The average area of this vehicle roof is about 1m2, compare with the capacity of battery (40KWH), the benefit and conditions of using PV panel is not worth the cost. Wind power is worth to mention because it is a potential direction for research. Every vehicle has to overcome air resistance when running and a wind turbine on top the vehicle can harness the wind energy as the car is operating. However, there is no satisfied outcome so far. In spite of recharging method, saving energy is another way to be economical. A new research shows that a special type of tyres can save energy and is not costly at all. According a study by the National Academies of Science, only $8 spent on a new type of tyre can save at least 2% of energy cost (Tonachel 2009).

6.4 Transmission Drive System:

The transmission on a hybrid car performs the same basic function as the transmission on a conventional car. Some hybrids, like the Honda Insight, have conventional transmissions. Others, like that Toyota Prius, have radically different ones. The following figure shows the transmission drive system for a hybrid car.

6.5 Aerodynamics:

The aerodynamic is the topic that study about the flow of the air around and through a vehicle. The air that flow will take some energy during the car moving through the air.

Dragis divided into 2 kinds that:

Frontal pressure-is the air flow around front of the car. When the car move through into the air, the air at the grill of car will start to compress and raise the air pressure in front of the car. At the same time air molecules will travel along the side of the car at atmospheric pressure compare to the front of the car. As principle of pressure, the higher air pressure in the grill of car will flow to lower pressure areas that are the top and bottom of the car.

Rear vacuum-is curse by the hole that left in the passing of air through the car. The hole such as area behind the car roof and rear of the car will free from pressure like the vacuum. From this reason the air molecules will be tried to fulfill this area. But during moving car the vacuum will be create one step ahead the movement of car. That mean the vacuum continuous occur in the opposite of the movement and the air cannot fulfill it. This situation is called flow detachment.

From the drag and rear vacuum principles, the car usually design for keeping the flow attachment as much as possible to produce the force from flowing air at the rear of car that should equal or exceed frontal pressure.

Lift and down force

Lift and Down force is the force that acts to any object to press it down during it moving through the still air. When consider to frontal pressure at the figure below, the frontal pressure will create down force and lift force from changing in pressure of flowing air

( http://www.up22.com/Aerodynamics.htm )

From the figures, it can say that the force will be created where the flowing air have low pressure. The force that occurs has direction opposite to the car body. The force occur by the moving of air that flow from higher pressure area to lower pressure area consider area between flowing air area with ambient air.

SAFETY AND HOMOLOGATION

Safety of occupants in any vehicle is of utmost importance and Hybrid vehicles are the future of automobile industry. Use of high voltage power sources, batteries, power electronics and plug-in charging equipments in HVs poses additional challenges for the vehicle manufacturers.

The various safety aspects that need to be considered and evaluated during design and validation phase are:

Ø Functional Safety

There are totally new standards which need to be considered for electric cars in the field of functional safety. Components which need to be tested and analysed for these standards include:

  • Drive motors
  • Controllers and gear mechanism
  • Electronic Control Unit (ECU)
  • Batteries and other energy storage devices
  • Power Electronics (Inverter, DC/DC transformer)

Safety objectives of these component and vehicle level tests incorporate the shutting down of electric power in case of a crash, protecting the energy stores from an overcharge and preventing electric drive motors from self-starting.

Ø Electric Safety

  • Measurement of the warming of motors, drives and components
  • Abuse tests (Short circuit and others)
  • Crash tests (High-voltage battery and cables)
  • Insulation Monitoring.

Ø Chemical Safety

Another new aspect of safety standards is the evaluation of the Chemical safety of electric cars with primary focus on energy storage devices. Potential risks are evaluated:

  • Which flammable and/or harmful substances can be released?
  • Evaluation of amounts and concentration of the released substances.

Ø Battery Safety

Battery safety in electric cars with is very important. Various aspects associated with the battery of an EV are:

  • Evaluation of emergency shutdown and errors (functional safety)
  • Inspection of the electrolyte retention and emergency outlet (chemical safety)
  • Testing and evaluating the galvanic isolation and shutdown concept (electrical safety)
  • Crash characteristics of the battery pack including the cooling mechanism (mechanical safety)

7. Product Design Specification:

From the technical research into the relevant areas of Hybrid vehicles it was possible to define the parameters of the Product design specification. The full vehicle specification can be seen in APPENDIX-D.

There were a number of basic principals driving the decisions made in the vehicle specification. This will be outlined in the part of the report. It was important that the vehicle meet the requirements of the project and governmental legislation requirements, while also being competitive with other products selling to the same market.

Safety specifications:

  • Anti-lock brakes.
  • Stability control.
  • Front side airbag.
  • Front knee airbags.
  • Full-length side curtain airbags.

Environmental specifications:

  • This commuter car can operated under the temperature between -300C to 400C which is better for the European countries.
  • Fuel emissions are minimal due to the mix of current power sources.
  • It can be operated in heavy rainfall, snow and dusty conditions too.

8sOperational Modes of Hybrid Cars:

The process prescribes the operating mode of a hybrid vehicle and there on to a large extent for overall design of the vehicle. If the vehicle is driven for the most part in the city for short distance, it may operate as an electric vehicle with the batteries being re-energized externally. For longer trips, a mode that mainly uses the heat engine may be engaged. All operating modes can be grouped into two general classes which are described below.

The simplest class of modes involves continuous operation of the heat engine at a maximum power and efficiency. The heat engine provides the power needed for motor at maximum vehicle speed. The additional power required for acceleration is supplied by the electric motor. Any excess power available from the heat engine is used to charge the batteries. Usually, the system is designed to operate so that the batteries are not exhausted.

The other class of procedure modes is the on-off mode. Here the heat engine operates only when the vehicle is running at high speeds or when the battery is exhausted. The battery powered electric motor provides the vehicle power at the lower speed and augments the heat engine during acceleration. Battery reduction may occur in many on-off operating modes so the range can be limited by battery capacity. Petroleum fuel expenditure can be lowered with this operating mode as more of the impulsion energy is provided from electricity if recharge is from an external, nonpetroleum electric source. All electric procedure at low speed also aids in reducing emission.

8. Designing of Commuter vehicle:

The initial requirements consideration for the chassis design are as below

  • Sufficient strength
  • Rigidity
  • Stiffness
  • Light weight construction
  • Low product cost

These are the basic requirement for the chassis design

By considering the all the above consideration the chassis design in the CATIAV5

By using the rough sketch from the considered car

By using the sketcher in the CATIA V5 chassis shape is designed and by using the some other options like pad , pocket , and trim chassis is design .

At the suspension edge , by clamping it and the forces are applied on the all the sides of the chassis

The 2d drawing of the chassis is as below

ANALYSIS :

Meshing the designed chassis by using the analysis and simulation

In the CATIA v5 meshing advanced meshing tools and generative structural analysis

By meshing the chassis using the Generative meshing analysis

From the above considerations and from the material report I preferred the material is aluminium . the frame is aluminium mono frame

The material properties of the aluminium are as tabulated below.

Material

Aluminium

Young's modulus

7e+010N_m2

Poisson's ratio

0.346

Density

2710kg_m3

Coefficient of thermal expansion

2.36e-005_Kdeg

Yield strength

9.5e+007N_m2

By considering the safety of the vehicle the high loads are applied on the chassis . that is 18000N is applied on the all sides of the chassis

Based up on the applied forces on the developed frame, the resultant forces are tabulated below

Components

Applied

Forces

Reactions

Residual

Relative

Magnitude Error

Fx (N)

-3.2187e-006

3.0575e-006

-1.6117e-007

2.1253e-010

Fy (N)

1.8000e+004

-1.8000e+004

-7.2905e-007

9.6137e-010

Fz (N)

-1.8000e+004

1.8000e+004

1.1278e-010

1.4872e-013

Mx (Nxm)

-6.1200e+003

6.1200e+003

-2.3926e-007

1.8451e-010

My (Nxm)

1.5048e+004

-1.5048e+004

7.3511e-008

5.6688e-011

Mz (Nxm)

1.5084e+004

-1.5084e+004

-6.8010e-007

5.2446e-010

The deformation of the chassis that can be observed in the below figure .

The below shown diagram is the generated figure from the analysis in the CATIA V5

The analysis of the chassis done on the basis of the safety of the vehicle, the load is applied on the frame in all the surface by considering the 18000N the above report shows the capacity that will hold the chassis when it is subjected to the load .

For the better results in the chassis the materials are high influences depend upon the material properties by considering the cast iron the weight of the chassis will increases but the capacity of holding capacity of the car is increases , or by considering the aluminium and magnesium and aluminium alloys cast moulding in the corners of the chassis is also increases the stiffness of the chassis , but considering the cost and the report from the materials the chassis is designed as totally in the aluminium.

The above figure shows the chassis position in the car . the car designed in the catia is as shown in the below figure

The drive line of the car is created in the CATIA v5 and the representation of the major parts that are car is placed in the chassis and designed in the CATIA

Product design

Then chassis is sent to workshop to create a prototype in the mean while using CAD the body of the car is designed.

After the required chassis is designed and sent to further development of the electric vehicle.

Suppliers of chassis.

Company Vehicle Security Installations Ltd

  • Contact details
  • Unit 4, Wilson Business Centre, Wilson Road, Huyton Business Park
  • City:Liverpool -L36 6AN State :Merseyside Country :United Kingdom

Company : Bridge of Weir Leather Company UK

  • Contact Details:
  • Clydesdale Works, Bridge of Weir
  • City :Renfrewshire -PA11 3LF Country:United Kingdom

Energy Requirements and Drive System:

Electric motor drive system is a core component of the car, so motor selection is very important. Cost can be calculated, and describes the performance of the motor parameters, drawn motor vehicle to be the characteristic curve can be used to produce the initial rapid selection of motors, and then the actual performance of the selected motor to determine the actual vehicle maximum speed, maximum acceleration and the other degrees of climbing. An example of this time uses a fixed ratio of the transmission system. Transmission system which is a simplified form, in practical applications can afford to be taken into account. The maximum torque transmission and the maximum allowed speed, etc.; In addition, Although usually more efficient for high rotational speed, overall performance was better, but will bring high-speed motor control system implementation difficulties, so this also needs to plan on the conflict's.

Motor selection

Induction motor parameters are:

Rated power: 25kW;

Rated speed: 4200rpm:

Peak power: 65kW;

Maximum speed: 11000rpm (last for 1 minute);

Rated torque: 70Nm:

Peak torque: 160 Nm;

Rated voltage: 190V;

Weight: 75kg;

Operating temperature: 20 ℃ - 80 ℃:

Efficiency: ≥ 85% (more than 80% of the high efficiency area of not less than 50% of motor area);

Electrical life: ≥ 300000km;

DC voltage input range motor controller: 200V- 400V:

Motor controller Life: ≥ 300000km.

This motor can be produced by an Indian company, Venus engineers.

Address: O- 53 Sector 1, Dsidc Bawana, Industrial Area, Bawana, Delhi - 110 039, India

http://www.venusengineers.in

The number and capacity of the battery pack option

1. Select the number of battery packs

Battery power for the motor in series, the minimum number of battery modules are:

NB,min---the minimum number of battery modules;

Um,min--- Minimum operating voltage of the motor, V;

Ub,min---The minimum voltage of the power battery module, V.

Battery is required to provide sufficient electrical power to meet peak power requirements of the motor, so the maximum number of battery modules is:

NB,max---The maximum number of battery modules;

Pm,max---Motor maximum power, kW:

Dpower---Battery power density, W / kg;

ηm - Efficiency ofmotor and control systems;

mmod - The quality of power battery module, kg.

6.3.2. The choice of battery capacity

The capacity of the main power battery electric vehicles from driving range dependent, power battery can be designed to limit the capacity of pure electric driving range of the range cars are:

Cb---Power Battery capacity, A•h;

L---Driving range, km;

e---Energy consumption per unit distance, kJ/ km;

Ub---Power battery module voltage, v;

DOD---Depth of discharge.

In the choice of battery capacity, it is necessary to meet the vehicle's driving range of design requirements, but also help to consider the spatial structure of the vehicle carrying capacity of the chassis. Because the choice of the larger battery capacity, battery storage of electricity by more driving range is extended, but the battery pack's weight gain, increased vehicle's curb weight, resulting in driving resistance also increases, which in turn affect the innocent electric car the driving range.

6.3.3. The number and capacity of the battery pack to determine

Calculated,

The minimum number of battery modules NB,min = 8,

The maximum number of battery module NB,min = 12, take NB = 10.

hence, we have the battery capacity of Cb ≥ 57.9A•h,

the actual take-capacity 120 A•h.

6.4. Battery selection

Lithium-ion battery pack options parameter as follows:

Option One:

Single Battery capacity: 120Ah;

Nominal Voltage: 3.6V;

Combination: 90 series;

Operating temperature: 20 ℃-60 ℃;

Option Two: single battery capacity: 11Ah;

Nominal Voltage: 3.2V;

Combinations: 11 and 100 series:

Operating temperature: 20 ℃-60 ℃;

The final layout scheme based on the vehicle to determine the groups of cells form and mounting structure.

This battery can be produced by an Indian company, Venus engineering.

Address: O- 53 Sector 1, Dsidc Bawana, Industrial Area, Bawana, Delhi - 110 039, India

http://www.venusengineers.in

ECAS control system

Drive Train Selection:

For the design of an hybrid car it requires some dynamic characteristics. Maximum speed and acceleration should be determined first, for this desired driving behaviour it depends on the selection of power train components. From the software DRIVESEL we can design an electric car by selecting the drive line components. It even shows the performance of the car like depending on it weight and speed limit. The power balance of a uniform car in motion on level road is shown below.

Here Nrd = power required to overcome the road.

Nair = power required to overcome air resistance.

Control System:

Once the general vehicle components involved in this design were viewed, a more detailed analysis of the flow of energy throughout this design was comprised below figure provides a systematic outputs (thin arrows) involved. The Control system focused on throughout this report is represented by the greenoutline, and the Electromechanical DesignManagement System is represented by the red outline.

( http://www.jason-fox.com/Junior-Design-Final-Report.pdf )

CONTROL SYSTEM FOR SUSPENSION

Remote control give single to ECU, then ECU will give single to solenoid valve, air bellow will work and control the softness and height of the suspension system. For the present project, marketing department try to make a contract with DUNLOP, they have been Designing and Developing ECAS systems since the 1980's. Working closely with major vehicle manufacturers, they have sold over 250,000 ECAS systems all over the world.

Address : Dunlop Systems and Components Ltd

Holbrook Lane

Holbrooks

Coventry CV6 4QX ,England.

http://dunlopsystems.com

MATERIAL SELECTION OF THE HYBRID CAR:

Chassis material :

Basically the chassis material plays a key role in the chassis design, because the requirements of the chassis design are as fallow

  • Light weight
  • Yield strength
  • Stress
  • Fatigue resistance
  • Cost

The materials that are generally use in the chassis are

Ferro's materials or cast iron gray :

The steel is the traditional material in the design of the chassis , the cast iron is the very second material that uses in the manufacturing of the of chassis and industrial revolution. Because it is the cheapest material in all the materials that are use in the automotive engineering

The carbon percentage consist in the cast iron (gray)is in between the 2-3% may be most of the 4% and the silicon percentage in the nearly in between 1-3 %

ALUMINIUM:

The aluminum is the most commonly used material in the chassis because of its light weight and the having the good yield strength and the thinner materials are used in the monocoque chassis when it it compared to the tubular based chassis

The aluminum is having nearly 500 MPa and yield strength , 82 GPa young's modulas and 550 tensile strength.

Now a days the chassis are made with the aluminum and the corner are strengthens by using the cast iron Maudling on the edges of the chassis , or magnesium and alloys are also used in the aluminum chassis

Magnesium :

The magnesium and the aluminum are the well for the airframe engineering and chassis manufacturing but the magnesium is little bit costly than aluminum but not like that the titanium

The monocoque chassis of precision welded from pressed sheet and it is made from the both in the aluminum alloys and in the magnesium alloys but when compared to the aluminum frame the magnesium chassis frame is 30 % lighter in weight.

The Body

The body should be lightweight and impact resistant. The capability of the car body can also be considered. The best material selections which we have are Woods, metals and Plastic. As, the body carries only its own weight so thinner materials are mainly used.

Plastics:

Thermoplastics are used normally by using die-casting which can be made into a complex shapes. The plastic is softened and then forced into a metal mold under pressure through die-casting. Rapid cooling is used to make the parts. Runners are still visible where the plastic came into the molds.

Fiberglass:

Hybrid car body can be made by using fibreglass. The woven Fiberglass cloth is wrought on a mold to that of a body shape, to form a fibreglass composite resin and plastic is painted; to share the advantages so that strength and stiffness increases.

Metal:

Aluminium is lightweight, so easy to shape and form. For many metal supply companies these are available as thin sheets. Aluminium is one of the regularly used metal, and it is painted with enamel paints.

Wood:

Wood is a good material selection. Pine is stronger and will not be easily damaged in a wreck. Balsa wood is much lighter, but also much more easily damaged. Both can be easily painted and are two good options.

The Batteries

The battery consists of cathode and anode, separated and connected by electrolyte. The cathode materials are made of lithium-metal oxides, vanadium oxides, olivines and rechargeable lithium oxides. The most used materials for lithium-ion batteries are Layered oxides containing cobalt and nickel. These show high stability in the high-voltage range but drawback for manufacturing is cobalt has limited availability in nature and is toxic. Lithium, graphite, lithium-alloying materials, inter-metallics, or silicon are the materials selected for anode. The most anodic material used is Carbonaceous because of low cost and availability. But, Charge density of Lithium is high compared to that of theoretical capacity.

The material which can withstand voltage and high temperatures are selected for the Electrolyte. Liquid Electrolytes are generally organic. Flammability is the most important property to be considered. Venting of the cell and subsequently the battery pose a danger which has low-boiling points and flash points around 300C.

The Wiring

For a hybrid car wiring is easy and straight forward. Copper is the second best metallic conductor, and is readily purchased at hardware electrical supply stores. Electricity passes easily through large diameter wire compared to that of small diameter wire which is sized in gauge. Lower the gauge number, larger the wire. By using a large diameter wire best performance will be achieved.

The Motor

Friction is the main thing that should be considered for the material selection. It is made of copper wire which rotates in between two or more magnets. Best way to achieve the most out of a motor is Maximizing its strength. Torque is controlled by the design of the motor.

Low end of magnets is magnetized by iron. The domains inside the iron, line up to give the piece a magnetic field when it is placed in a strong magnetic field. Iron will be easily demagnetized as the field is weak. Iron-Cobalt magnets have stronger magnetic fields which cannot be demagnetized easily. Most likely these type of magnets are used. At present magnets are made from iron-neodymium which is extremely strong.

3.1 PISTON.

As the engine starts the piston heats up rapidly and expands in diameter. The cylinder block enclosing the pistons has a large heat capacity. And employs a water cooling system, So it heats up slowly. Due to the large amount of heat generated in engine cylinders walls the piston material starts elongation and touches the walls. So, To prevent that we will choose the materials having low thermal expansion property. By using the performance indices we will get the range of materials having low thermal expansion in CES software as shown in the figure .

The yield strength should be high for the piston; from the following equation we are giving the performance indices to the CES for knowing the low thermal expansion property range of material.

σ = E α â–³T

From the above equation we will clearly says that E is inversely proportional to the thermal


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