Some ways to cope with air pollution from vehicles
A. Controlling our vehicles emission
1. Driving the vehicle in good way
The ways we drive indirectly affect the CO combustion level. Try to drive with adjusting the machine cycling, speed, transmission gear and the loading to get efficient performance, which is profitable not only for the machine but also for the environment. Don’t race the car engine. Slowing down and watching the idling save the fuel (save your money) and have a big impact in burning gasoline. The using of high gear on low speed triggers incomplete burning process. Besides, use car on its passenger capacity. Do not use it alone while there are six more seats empty. That will waste the energy available.
2. Maintaining the vehicle well
Do some routine maintenance such as changing the oil, sparkplug and platinum. Changing the lubricating oil is very important. If the viscosity isn’t appropriate, there will be a compression leakage which draws incomplete burning process. Thus, the CO emission is increasing; and the machine will be dull faster. Sparkplug, platinum and condenser are electric components which support the burning process. (Reparasi dan Perawatan Mobil, 2000) If those components don’t work well, so do the burning process. Those will give the same effect – the increasing of CO emission.
3. Having the vehicle tuned up regularly
Just a simple tune up often improves fuel efficiency by half. Tune up is done on the following parts:
a. Cooling system
- Level of the cooling water
- Quality checking
- Leakage checking
- The pressure of radiator cover valve
- Cooling water capacity
b. Fan belt
Check fan belt for these possibilities:
- Cracked, reformed, too tight, or dull
- Contaminated with oil
- Imperfect bond between fan belt and pulley
c. Air filter
Clean the air filter. Keep dirt or another stuff from the carburetor.
d. Battery
Check the battery from these possibilities:
- Rusty battery supporter
- Loose terminal connection
- Rusty or broken terminal
- Broken or leak battery
- Battery electrolyte’s specific gravity (check with hydrometer)
- The decreasing of battery electrolyte’s level
e. Lubricating oil machine
Check the lubricating oil machine from these possibilities:
- The decreasing of oil level in the machine
- The decreasing of oil’s quality
- The need to change the filter
f. Sparkplug
Check the sparkplug from these possibilities:
- Crack or broken screw and isolator
- Broken or reformed gasket
- Dull electrode
- Burnt or dirty electrode
g. Distributor
Check the distributor from these possibilities:
- Cracked, rusty, burnt or dirty
- Burnt terminal electrode
- Weak distributor spring
h. Valve space
i. Carburetor
Some component’s works in carburetor are checked. Those components are:
- Throttle valve
- Acceleration pump
- Choke
- Idle rotation
(taken from Reparasi dan Perawatan Mobil, 2000)
4. Having the emission checked
In order to know our vehicle’s emission, we need to have it checked in the garage or in the police station. In Jakarta, emission test becomes a requirement for the payment of Motor Vehicle Tax, but some of the officers still ignore it. This regulation is mentioned in Jakarta Regional Regulation (Perda) No. 2, 2005 which was established on April 4, 2005. It states the duties for every vehicle to pass emission test and also states the prohibition of smoking in public places. (Edukasi Udara Bersih Terhenti, Kompas, March 26, 2006) CO, HC and SPM are checked in this process. Some countries check the CO2 release also. To reduce emission, there are some requirements which have to be accomplished on the following:
- High-octane-number fuel
- Unleaded fuel
- Clean ignition chamber
- Good ignition
- Good mixing of the fuel and the air
- Installation of catalytic converter (Reparasi dan Perawatan Mobil, page 9, 2000)
5. Using environment-friendly fuel
a. Unleaded gasoline
Nowadays gasoline in Indonesia, called Premium has octane number 87, and contains 0.7 grams of TEL (Tetra Etil Lead) per liter. It is considered not being a good gasoline if we talk about its impact to environment and human health, since it still contains lead on it. The inconsequence of our government makes it still be in process to reach zero-lead gasoline, while world’s unleaded gasoline consumption has reached 80% of overall gasoline consumption. Even though Mining and Enery Ministry decree No. 1585, 1999 about elimination of lead in gasoline had been issued, the adjournment of leaded gasoline elimination keep continues until now. Unleaded gasoline refers to Euro II vehicles emission standard where gasoline is lead-free and diesel fuel has low sulfur percentage less than 500 ppm. (Witoelar, Rahmat, November 22, 2005) European Union has determined Euro 5 standard since 2005.
b. Pertamax
Pertamax is the improvement of premium gasoline. It has a big octane number (95). Its efficiency is much better than premium’s, thus the emission is less.
c. Bio-fuel
Bio-fuel is divided into two, bio-diesel and bio-ethanol. Biodiesel is a mono-alkyl ester-based oxygenated fuel, produced from a variety of renewable resources, including waste vegetable oils, cooking oil, soybean oil and animal fats. About 90 percent of US biodiesel is made from soybean oil, (www.planetark.org, February 2, 2006) and biodiesel in Indonesia is potentially made from oil palm and castor oil plants. Biodiesel can be used in any diesel car without any modification needed. It is mixed with usual diesel fuel in any amount. It even can be used in its pure form called ‘neat’ bio-diesel or B-100. The most commonly used form of biodiesel is B20, a blend of 20 percent biodiesel with 80 percent diesel fuel. The use of B20 balances the emissions benefits with the cost, cold weather and solvency considerations. (www.pugetsoundcleancities.org, 2005)
Biodiesel can also be used as a petroleum diesel fuel additive to provide increased lubricity. This application is valuable when using low and ultra-low sulfur diesel fuels, as the reduction sulfur levels results in decreased fuel lubricity. Even at a low percentage blend, such as 2 percent, biodiesel will provide sufficient lubricity. (www.pugetsoundcleancities.org, 2005)
The emissions benefits of biodiesel include significantly lower emissions of carbon monoxide, hydrocarbons and particulate matter compared to petroleum diesel fuel. Emissions also contain lower levels of the toxic contaminants related with diesel fuel. In addition, biodiesel has a few amounts of sulfur, resulting in significant reductions in sulfur dioxide (SO2) emissions, which contribute to the development of acid rain. Emission reductions are achieved without the need for additional emissions control equipment, but biodiesel is compatible with equipments in new diesel engines or after-market equipment, such as particulate filters, installed on older diesel vehicles. Biodiesel is biodegradable and non-toxic. As a result, biodiesel doesn’t pollute soil and water. The percentage of biodiesel used in a blend will affect the degree of these benefits. (www.pugetsoundcleancities.org, 2005)
Bioethanol is ethanol (alcohol) which is made from renewable resources. It is composed from the fermentation and distillation of sugar cane or grain crops such as corn, barley and wheat. In US, it is primarily made from corn. (www.planetark.org, February 2, 2006) Waste products from agricultural and forest practices, called "cellulosic biomass", are also used to make bioethanol. In its utilizing, bioethanol is mixed with usual gasoline. It needs modification on the gasoline-powered car to use eighty five percents ethanol (E85), while for E10 (10 percent ethanol) or lower, the vehicle doesn’t need any modification. Bioethanol is usually used to run flex-fuel car.
E85 vehicles may have a more limited range than gasoline vehicles. One gallon of E85 only provides the same energy as 0.72 gallons of gasoline. The ability to use pure gasoline in flex-fuel vehicles provides flexibility when operating the vehicle in areas where E85 is not available. Ethanol is corrosive so that special materials are required for fuel lines, hoses, valves, gaskets and fuel tanks. In severe cold weather, there may be start problems. It is recommended that the ethanol content is lowered in severe cold weather conditions. (www.pugetsoundcleancities.org, 2005)
Emissions reductions for E85 range from 30 to 50 percent reductions in hydrocarbons and nitrogen oxide. Sulfur dioxide emission is reduced, and greenhouse gas emissions (carbon dioxide / CO2) is also reduced significantly.
Indonesian government starts to realize the big potential of our plantation area to produce bio-fuel. The wide oil palm plantations available enable us to manufacture more bio-diesel; hence it can meet local demand of bio-fuel. Furthermore it can be exported to neighbor country. Bio-diesel has been sold in Indonesia but in very limited stock in view of the fact that bio-fuel manufacture has just been developed. Referring to the general policies of energy sector – Blue Print Pengelolaan Energi Nasional – bioethanol and biodiesel is targeted to reach 2% of fuel consumptions in 2010 and 5 % in 2025.
B. Using low-emission vehicles
1. Natural gas vehicles
Natural gas is fossil fuel in the form of gas which primarily consists of methane. The other substances are hydrocarbons such as ethane, propane, and butane. (id.wikipedia.org, 2006) Natural gas is extracted from gas wells or together with crude oil production. It can also be produced as a by-product of landfill operations, dairy farms, waster water treatment plants, etc. It can be stored on a vehicle in gaseous form, compressed natural gas (CNG), or as a liquid, liquid natural gas (LNG). (www.pugetsoundcleancities.org, 2005) Natural gas can also be blended with hydrogen to create a hydrogen/natural gas (HCNG) blend. The HCNG blends of 10% hydrogen and 90 % methane are called hythane. (Flint, Jerry, 2006)
Natural gas vehicles vary from passenger vehicles to heavy-duty trucks. CNG light-, medium-, and heavy-duty vehicles are available from automobile manufactures. Also, gasoline and diesel vehicles can be converted to operate on natural gas. LNG vehicles are also available, though they are focused on heavy-duty vehicles. (www.pugetsoundcleancities.org, 2005)
Natural gas vehicles produce lower carbon monoxide, particulate matter, nitrogen oxide, and carbon dioxide emissions compared to gasoline and diesel vehicles. In some cases, natural gas engines have reduced carbon monoxide (CO) and particulate matter emission over 90%, and have reduced more than 50% nitrogen oxides (NOx). In addition, natural gas vehicles produce significantly lower evaporative emissions during fueling and operating. Natural gas also contains relatively few toxic contaminants. (www.pugetsoundcleancities.org, 2005)
The cost of natural gas vehicles from automobile manufacturers is 25% higher than gasoline vehicles. Converting a gasoline passenger vehicle or light-duty truck to operate on natural gas costs approximately $5,000. These costs may be compensated by lower operating and maintenance costs. Usually, natural gas fuel is less expensive than gasoline and diesel. (www.pugetsoundcleancities.org, 2005)
In Jakarta some of the taxis have already converted their engine for natural gas using.
2. Propane gas vehicles
Liquefied petroleum gas (LPG) or propane, is a hydrogen-rich and high-octane fuel. The majority of the propane available today is a by-product of natural gas processing, and the rest comes from crude oil refining. Propane is stored on vehicles in under pressure tanks in liquefied form. As the pressure is released, propane gas enters the engine.
Propane has been used as a vehicle fuel since the early 1900’s and continues to be a viable technology. It is estimated that propane is currently the most widely consumed alternative fuel in the United States, used in vehicles include trucks, school buses, taxes and police vehicles. The power, acceleration, payload, and cruise speed of propane vehicles is comparable to an equivalent internal-combustion engine. The operating range of propane vehicles is also usually comparable to gasoline vehicles. Propane vehicles generally have lower emissions of reactive hydrocarbons, nitrogen oxides, and carbon monoxide compared to gasoline and diesel vehicles. It is nontoxic, nonpoisonous, and the least flammable among alternative fuels.
Propane vehicles from automobile manufacturers are slightly more expensive than gasoline vehicles, and vehicle conversions can cost from $2,500 to $5,000, depending on the vehicle. Propane fuel prices are, on average, equal to or lower than unleaded gasoline prices. Operating and maintenance costs are generally lower than gasoline and diesel vehicles. Propane makes a more complete combustion than gasoline, resulting in fewer engine deposits, fewer oil and filter changes and increased engine life. Experience has also shown that propane engines can last 2 to 3 times longer than gasoline or diesel engines.
(taken from www.pugetsoundcleancities.org, 2005)
3. Flexible-fuel Vehicles (FFVs)
Flexible-fuel Vehicles (FFVs), generally called flex-fuel can works on two or more sources of fuel. Some run on gasoline and ethanol, some run on gasoline and natural gas, and some even can work on those three kinds of fuel, gasoline, ethanol and natural gas. The first sort of FFV works fully with the power from gasoline, or the mixing of gasoline and bio-ethanol up to 85% of bio-ethanol. Natural gas on flex-fuel car is a cheap fuel, but compared to other flex-fuels it has the lowest mileage and takes a lot of space in the trunk. (en.wikipedia.org, 2006) Usual gasoline-powered car can be converted into flex-fuel by adding some certain components.
Flex fuel car has so many advantages. One of them is that we can save money from buying gasoline. Today’s price of gasoline has reached $60 per barrel, and the oil stock in the earth is much decreasing, drawing oil rarity and difficulties to get it. Flex fuel car is very flexible. The machine can recognize the amount of bio-fuel which is used and adjust the machine’s work appropriate with the fuel. Air pollution can be reduced, as gasoline, which burning emits hazardous smoke, is replaced by ethanol partially.
Brazil outstandingly excels in flex-fuel car as it has abundant sugar cane plantations to produce bioethanol. Flex-fuel cars manufactured by Honda and Toyota will be put for sale in Indonesia when bio-fuel selling network is available.
4. Hybrid Electric Vehicles (HEVs) and Plugged-in Hybrid Electric Vehicles (PHEVs)
Hybrid electric vehicles (HEVs) are vehicles which use two different power sources. The majority of available hybrids use traditional gasoline or diesel engines, in combination with electric motor. Some hybrids use alternative fuels, such as natural gas for heavy-duty using. The result is a vehicle with low emissions and high fuel efficiency. They are available mostly in the form of car. When the car is used in low speed, the power is taken from the electric cell. But when there is a significant acceleration and high speed, the engine will work.
The electricity of this car is generated from the brake system. While the driver pushes the brake pedal, kinetic energy is converted into electricity and then stored in the battery. At a red light, the engine shuts down entirely. Because hybrid car’s source of support does not come only from the battery, the car’s size can be must smaller than the bulky and costly battery-operated cars. (C’nS Vol.5 No. 38, page 38, 2006)
The use of the electric motor allows hybrid electric vehicles to significantly reduce emissions compared to traditional gasoline vehicles. Emissions reductions depend on the fuel efficiency and cleanliness of the gasoline engine and the amount of power provided by the electric components. In some light-duty vehicles, exhaust emission of hydrocarbons, nitrogen oxides and carbon monoxide are reduced over 50 percent, and have been shown to be reduced as much as 90 percent. (www.pugetsoundcleancities.org, 2005) In addition, it produces no noise.
Beside of HEVs, there is Plug-in Hybrid Electric Vehicles (PHEVs) which has additional battery capacities and the ability to be recharged from an external electrical outlet. They can travel solely using battery power, and when the batteries are sufficiently depleted, the vehicle relies on the internal combustion engine. PHEVs are commonly called "grid-connected hybrids," "gas-optional hybrids" (GO-HEVs), "full hybrids," and are sometimes called HEV-30 (for instance, to denote a hybrid with a 30-mile (50 km) electric range, compared to a HEV-0 (a non-plug-in hybrid). The common range of PHEVs is 20-60 miles. (www.pugetsoundcleancities.org, 2005)
Hybrid is the most concerned and relevant breakthrough in alternative energy car and environment-friendly car to be used these days. The weakness is on its high price. One hybrid car costs about $45.000.
So far, PHEVs in USA have not been commercially produced by original equipment manufacturers (OEMs) but conversions of HEVs have been completed by other groups. Hybrid in Indonesia hasn’t been well known and is still in research phase. BPPT (Badan Pengkajian dan Penerapan Transportasi) and Ristek are now in research of hybrid car from Honda, which is targeted to be finished by August 2006. (www.bppt.go.id, March 2, 2006) If the result is satisfying, it’s very possible that hybrid car will be well developed in Indonesia.
5. Gasoline-hydrogen vehicles
Gasoline-hydrogen cars use hydrogen and gasoline as the energy source. Unlike fuel-cell, which only use hydrogen, gasoline-hydrogen car also use gasoline to get additional power. This type of car is leased by Mazda Motor Corp, realizing that fuel-cell cars are decades away from mass production, due to high development cost and lack of infrastructure. Gasoline-hydrogen cars can run on gasoline when the hydrogen is run out, and are using existing engine part and production facilities to lower costs. Gasoline-hydrogen car from Mazda is powered by iconic rotary engine, and can switch between hydrogen and gasoline fuel with the flick of a switch. It can cruise for a maximum 100 km on hydrogen and 549 km on gasoline. (www.planetark.org, 2006)
C. Using emission-free vehicles
1. Bicycles
Bicycles have been the cheapest vehicles. They have easy maintenance and need no fuel. They really contribute to near-distance transportation without emitting pollution. Besides, biking is very good for our health. There are two main functions of biking related to our health. The first is endurance. It trains the stamina of heart and lungs. When we pedal a bike, vascularisation, and oxygenisation are increasing. Heart pumps blood more actively and lungs work harder to supply the oxygen. The second function is strength training. Biking trains certain muscles. When we pedal a bike, thigh muscles and surroundings are trained. (www.kompas.com, 2006) Many people do biking to burn calories, lose weight, or slim the stomach and waist.
Biking can be a very exiting hobby. Many people love to ride a bike as an exercise, recreation, or competition. According to a Kompas online article, Hobi Bersepeda, Seru dan Bikin Sehat, there are two kinds of biking, on road and off road. In on road biking, people bike on the city street; while in off road people bike on bumpy ground. The youth usually prefer the off road biking to the on road one because of its challenge and adventure.
Thus, bicycle is a good choice of vehicle. We should ride a bike in our daily life instead of driving a car or motorcycle, especially when the distance is not so far. One country that concerns much about bicycle is Holland. All people there ride bicycle for their transportation. That act obviously lessens the air pollution problem.
2. Hydrogen Fuel-cell vehicles
A hydrogen fuel-cell vehicle is powered by an electric motor running on electricity generated by a fuel stack which uses hydrogen as its energy source. It generates no CO2 or other exhaust gas emissions, and completely free pollution. The emissions are only water vapor and heat.
The components of fuel-cell car are very far different from the usual gasoline powered car. Honda, an automobile company which excels in fuel-cell car, explains on its website (world.honda.com) that its fuel-cell cars have the main power train components on the following:
a. Fuel Cell Stack
Fuel Cell Stack takes part as the main power source. The fuel cell stack is a PEMFC (Proton Exchange Membrane Fuel Cell) electrical generation device that employs an electrochemical reaction between hydrogen (H2) and oxygen (O2) to directly convert chemical energy into electrical energy. This can be viewed as the reverse of the principle of electrolysis, in which an electrical current is used to separate water (H2O) into hydrogen and oxygen. The system that is capable of continuous electrical generation when supplied with hydrogen and oxygen, simultaneously generating electricity and water, with no CO2 or other harmful emissions.
When hydrogen is delivered to the hydrogen electrode, it is ionized by a catalytic reaction with the platinum electrode and emitting electrons. After emitting electrons, the hydrogen ions pass through an electrolytic membrane (ion exchange membrane), where they bond with oxygen ions from oxygen delivered to the oxygen electrode (+) and the previously emitted electrons arriving via an external circuit. This reaction creates DC electrical current, generating electricity. Water is generated at the oxygen electrode as a by-product, and some of this water is used for humidification.
b. Humidification system
The recycled water recovery (fully independent) humidification system recycles water generated in the FC Stack for use in air humidification.
c. PCU Power Control Unit
It controls electrical systems, including FC Stack output, capacitor output, drive motor output, air pump, and cooling pump.
d. Fuel cell cooling system
It’s equipped with one fuel cell system radiator (large) and two drive train radiators (small), and specially developed for use in fuel cell vehicles for improved cooling performance.
e. Drive train
It is composed of a drive motor, transmission, and drive shaft. The drive motor combines high efficiency with high output and torque.
f. High-pressure hydrogen supply system
It is equipped with one or two tanks. Can be filled with up to 156.6L of hydrogen at approximately 350 atmospheres
g. Air supply system
An air pump with a high-voltage electric drive motor supplies the FC Stack with air at the appropriate pressure and flow rate.
h. Ultra capacitor
Independent ultra-capacitor contributes as a supplementary power source to deliver abundant power to the motor. It delivers instantaneous high-output assist during startup and acceleration, while efficiently recovering energy generated during braking. It combines high responsiveness with high efficiency.
Power is distributed brilliantly, mostly generated from fuel cell stack and ultra capacitor. In start up and acceleration, ultra-capacitor assists the fuel cell stack to achieve crisp, responsive performance. In deceleration, the ultra-capacitor recovers the energy released during deceleration and stores it along with power from the fuel cell stack. It results in greater fuel efficiency and a natural feel on deceleration. In gentle acceleration and cruising, the output is from fuel cell stack. When the car does idle stop, the auto idle stop system shuts off output from the fuel cell stack to reduce fuel consumption, and the electricity required to operate the air conditioner and other components is supplied by the ultra-capacitor. Output of the fuel cell stack may not shut off under some conditions.
Fuel-cell cars excel in some aspect. They emit no pollution, no noise, and only produce water, realizing zero-emission vehicle. But beneath that, fuel-cell cars have a lot of weaknesses which make them difficult to be developed and used by the public. The cost is too high and there should be new infrastructure for the hydrogen gas stations. Now fuel cells have been used by a few people in California by leasing it. They haven’t been on sale yet. Twenty two hydrogen fuel stations have been built, and 134 fuel-cell cars have been operated there. California has a plan called Vision 2010 or Hydrogen Highway and the California Fuel Cell Partnership which goal is to have hydrogen fueling stations along state highways by 2010. (Deagon, Brian, 2006) In Japan, 13 state-owned hydrogen fuelling stations have been made.
3. Battery Electric Vehicles (BEVs)
As seen from their name, battery electric vehicles use electricity as the power supplier. The electricity is stored in batteries, and to recharge it, the owner should only plug the batteries into an electric outlet. Many EVs get some additional energy stores through regenerative braking. The range of an electric vehicle is limited, generally between 35 and 80 miles, depending on the batteries used, the number of batteries, vehicle weight, weather and driving conditions. This makes EVs most suitable for short-distance trips involving many starts and stops, such as airport applications, delivery vehicles, transit and personal use. Electric vehicles can be designed with the comparable speed and power of conventional vehicles. (www.pugetcleancities.org, 2006)
It was first invented by Robert Anderson in 1832, when battery technology was so limited that they could only cruise about 40 or 50 miles per charge. (www.peterson.org, 2006) Now, after long researches, an EV can cruise until 90 miles. But still EV is not convenience enough due to its limitations on the cruising range and long charging time (six to eight hours). The problem is on the battery size, weight and its power capacity. To make battery with good capacity size enlargement is needed; make the vehicle not compact. Besides, electric vehicles are expensive. The cost depends on the vehicles’ size and the battery technology used. However, EVs produce no noise, have low maintenance cost, and emit no emission.
Electric vehicles are zero-emission vehicles in terms of tailpipe emissions. However, electric used in EVs are generated by electric plants, and some plants, especially coal-fired power plants, emit big amount of pollutants. It is important that these factors be compared to the life-cycle emissions and environmental consequences of petroleum extraction, production and distribution. Studies have concluded that recharging electric vehicles using coal-fired power plants would still produce 17 to 22 percent fewer carbon dioxide emissions than gasoline powered cars would; and the recharging of vehicles using natural gas powered plants would produce 48 to 52 percent fewer carbon dioxide emissions. (www.pugetcleancities.org, 2006)
The products of electric-powered vehicles are various, starts from cars, motorcycles, bicycles, until scooters. Neighborhood Electric Vehicles (NEVs) are defined as four-wheeled electric vehicles having a maximum speed of 25 mph. The vehicles typically obtain a 30 mile range per charge. NEVs are perfect for short-trip neighborhood operation. The largest source of gasoline vehicle emissions occurs during short-trip operation. As electric vehicles, NEVs have zero emissions and thus have the potential to keep good air quality. The benefits also include lower cost (average of US$6,000 to $15,000), reduced noise in communities, reduced parking pressures (2 or 3 vehicles can fit in a conventional parking space), and low cost to operate and maintain. Several vehicle styles are available, including 2 and 4 passenger models and vehicles with utility, truck-style beds. NEVs have been able to be licensed for on-road use in Washington State since 2003. (www.pugetcleancities.org, 2006)
Here, in Yogyakarta, electric bicycles are obtainable. One of the vendors is ‘Esa Jaya’ shop on Jl. Ahmad Dahlan which sells electric bicycles made in China labeled ‘Sun Race’. We can get it for only Rp 2,500,000.00. The cruising range is fifty kilometers per charge, with the maximum speed of 30 km/hour. Once we purchase it, we must charge the battery for about eight hours. But on the long run, we just need to plug it in within two to three hours, the same time needed to recharge our mobile phone battery.
4. Solar-powered vehicles
Solar-powered vehicles use solar light to generate energy. They are designed and built only for racing as they aren’t practical for transportation. They have limited seating (usually one, sometimes two people) and very little cargo capacity, and they can only be driven during the day. However, they offer an excellent opportunity to develop future technologies that can be applied to practical applications.
The energy from the sun strikes the earth throughout the entire day. However, the amount of energy changes due to the time of day, weather conditions, and geographic location. The amount of available solar energy is known as the solar insulation and is most commonly measured in watts per meter squared or W / m 2. In North America, on a bright sunny day in the early afternoon the solar insulation will be roughly around 1,000 W / m 2, but in the mornings, evenings, or when the skies are overcast, the solar insulation will fall towards 0 W / m 2.
Solar-powered cars which are based on American Solar Challenge Regulations have certain energy flow process. Energy starts flowing in a solar car when the sunlight hits the cells of the solar array, which produces an electrical current. The energy (current) can travel to the batteries for storage; go directly to the motor controller, or a combination of both. The energy sent to the controller is used to power the motor that turns the wheel and makes the car move. Generally if the car is in motion, the converted sun light is delivered directly to the motor controller, but there are times when there is more energy coming from the array than the motor controller needs. When this happens, the extra energy gets stored in the batteries for later use. When the solar array can't produce enough energy to drive the motor at the desired speed, the array's energy is supplemented with stored energy from the batteries. Of course, when the car is not in motion, all the energy from the solar array is stored in the batteries.
There is also a way to get back some of the energy used to boost the car, well known as regenerative braking. When the car is being slowed down, instead of using the normal mechanical brakes, the motor is turned into a generator and energy flows backwards through the motor controller and into the batteries for storage. The amount of energy returned to the batteries is small, but every bit helps.
The most unique part of solar cars is the bodies. The solar array makes them exotic and eye catching. Solar cars are grouped into several body classes, but every car is unique because there are no established standards for solar car design, with the exception of dimensional constraints. The main goals when designing the body are to minimize the
