Electric Propulsion Systems

By Ahmad Nugroho

Hybrids are designing to apply electric propulsion systems which demonstrate to be really efficient and as well as environmentally friendly. There perhaps several approaches and techniques in order to carry out movement applying electrical power but the main idea is still the same. These arrangements are already operative and will encourage help produce alternate fuel.

What is Electric Propulsion?

Electric propulsion is the speedup of gases in order to produce propellant thrust through electric and magnetic body forces, electric body forces or electric heating. The electric propulsion system is usually integrated in rocket science wherein it manages energy sufficiency to produce a powerful force. An electric propulsion system is an alternative to atomic propulsion system. The total force is less powerful compared to a atomic rocket but still sufficiency to produce effects.

According to a figure of studies, any engine exploited as a main source of such powerful propulsion must produce beat speeds of around 10 to 20 km/s. There are also storable chemical systems applied in rockets with an exhaust speed of around 5 km/s but overall is less efficient.

Propulsion systems that don’t require energy through chemical reactions are still needed. There are electric propulsion thrusters able to develop exhaust velocities of around 10 to 20 km/s which increases payload and reduces propellant mass. The results however, are less powerful thrusters consuming larger quantities of power.

The 3 Categories of Electric Propulsion

1. Electro thermal propulsion is when the propellant is electrically heated then isentropically expanded through a C/D or convergent/divergent nozzle. The system works as electrical energy heats propellants that produce gases as a result. The gases are sent through the C/D nozzle creating thrust. Catalyzed hydrazine or another neutral gas is used in thrusters like arc jets and resistojets.

Arc jets can also be used to heat the propellants via an electrical arc discharge. The arc in the arc jet is a beam of electrons produced from the cathode tip then gathers at the anode. Since an arc jet has a cathode and an anode, a constrictor is also present which is a narrow pathway between the two charges.

2. Electrostatic thrusters are also called ion thrusters. These use an ionized propellant accelerated through electric fields applied directly like gridded ion thrusters and Hall thrusters. The technique of propulsion is also acknowledged as ion propulsion technique since ions are mainly used in the process. Electrostatic energy is used to produce propulsion.

The electrons from an atom are stripped off then converted to ions. The ions are accelerated by electrical forces to heat without needing thermal energy producing thrust. The atoms after losing electrons become positively charged.

3. Electromagnetic thrusters produce thrust using electric and magnetic force that interact with charged plasmas like ions and electrons. An example of these is the magnetoplasmadynamic thruster or MPD. The system heats the propellant to a plasma state before being accelerated. A large current is passed by electromagnetic forces through gas in order to ionize the propellant. Plasma is the ionized propellant which is then accelerated by Lorentz force, an electromagnetic force producing thrust.

Effect on Fuel

Decoupling engine speed and power output from the propeller will provide the opportunity to improve propeller efficiency. Since electric forces and electromagnetic forces contribute for support, petrol and diesel propulsion systems in vehicles will diminish the chances of wasting a huge part of power and energy.

The chances of engine overload are eliminated resulting to better fuel economy and better fuel consumption rate. Additionally, there is higher efficiency over longer distances and various speeds and loads.

A study conducted to check how much electric propulsion systems can help diesel and gasoline engines showed that at least 10% fuel savings is attained by simply allowing the engine to move along with the load reducing inefficiencies due to low load with high-velocity. Larger propellers can also save as much as 7% of fuel compared to traditional models.

With the total load split between multiple generators, as much as 20% of fuel can be saved plus another 13% by matching the power produced by the engine to the power required by the propeller. A variable-speed generator will help accomplish this. Overall, 30% to 50% can be saved compared to a very efficient diesel-electric or gasoline-electric system.

By Ahmad Nugroho

Hybrid electric vehicles are means of transportation that incorporates the use of an electric system in the main engine. Since gasoline engines have caused a variety of environmental pollutants, people are now starting to rely on electric power which has zero emission and are more fuel efficient. Here is an overview about hybrid electric vehicles.

What is a Hybrid Electric Vehicle?

A hybrid electric vehicle or HEV is a vehicle that is a combination of a rechargeable energy storage system or RESS and a traditional propulsion system. It saves more fuel and also covers more distance compared to battery electric vehicles since charging is done through a variety of methods instead of a lone external source. The propulsion power systems of various hybrid electric engines may be composed of the same parts or subsystems.

Usual hybrid electric models have an ICE or internal combustion engine as well as electric batteries that support the main electric motors. The mechanisms of the HEV have improved significantly with the discovery of regenerative braking wherein kinetic energy can be stored. Fuel is conserved more and emission is minimized as much as possible. Drivers get to cover longer ranges as well without worrying about speed and performance.

The combustion engine too can generate electric power through a spinning electrical generator. The energy either provides power directly to the motor or recharges the battery. The internal combustion engine automatically shuts down when idling but immediately restarts as necessary. The engine is also considerably smaller which is more efficient.

Do HEVs Still Use Gas and Diesel?

Gasoline engines will most likely remain in the hybrid vehicle scene for years to come since it generates power like no other discovered or affordable material can. Petroleum gasoline is considered as the main fuel source but can be mixed with different concentrations of ethanol from other energy sources. HEVs use up around 15% bioethanol like other internal combustion engines but manufacturers are currently finding ways to improve ratios for increased fuel efficiency and decreased emission.

There are diesel electric engines wherein a diesel engine is mainly used to provide power. Diesel can prove to be more efficient than gasoline although speed and noise may not be its best features. Diesel can be better-performing and can provide power for long periods of time without wearing much.

Gas mileage is also better due to its high torque while using biodiesel. The need for petroleum is minimized depending on the type used. Although diesel are usually known to drive bigger transportations like trucks, SUVs and vans, hybrid diesel-electric vehicles have also appeared in smaller versions like sedans and other passenger cars.

Hybrid Electric Vehicle Types

Hybrid diesel-electric motorcycles have been created having a top speed of around 800 mph with a very affordable retail price of $500. Several known automobile manufacturers have also joined the bandwagon like Honda, Ford, General Motors, Mazda, Nissan and Toyota. These big names are currently innovating to continuously provide well-performing vehicles with all the advantages.

HEVs have been very specific in being made available for future taxicab models. Since these vehicles are usually on the go all day long, fuel and emission can be improved through automatic engine shutdown, regenerative braking and idling. There are plug-in models in which taxicabs can conveniently recharge batteries at designated stands throughout the city. Plug-in hybrid electric models are also available in the form of sedans and mini-cars.

Hybrid-electric buses and trucks are also circulating due to the many advantages offered. The diesel engine is smaller which means that it is more efficient. There is also a 1.9-liter diesel engine instead of the 7.0, emitting less harmful gases. Emission reduction has been reported to be around 30% while fuel efficiency is around 40%. Some hybrid-electric buses have gas turbine generators. More efforts are exerted to convert other means of transportation like trains.

Several other types of HEVs are available today and are being used in various projects. The military uses diesel-electric hybrid trucks which has a fuel cell auxiliary power and diesel electric unit. The United States Army began using hybrid electric drives for all vehicle systems and subsystems. Other notable trucks have also found their purpose in commercial sectors, scientific projects and mining endeavors.

Alternative Fuel Vehicles – The Story

By Ahmad Nugroho

Do you know how many types of vehicles there are in all? Since the creation of the first crude automobile, several models and types have been created to suit the needs of people. These were developed in order to provide a safe, efficient and economical means of transportation. Some are built for luxury, others for practicality and some for environmental purposes.

Cruder Forms

Vehicles were first made thousands of years ago. The earliest forms of vehicles were actually living things like horses, elephants and camels. With the invention of the wheel around 3000 B.C., chariots, carts and horse-drawn carriages came into existence. The wheel has certainly paved the way for modern transportation as it is still very much present today.

Cycles were created around the 19th century which comes in many forms. Bicycles are one of the most common types of vehicles available today. There are also tricycles, quadricycles and unicycles. These vehicles mainly use a chain that goes around the wheels for propulsion. Cycling is a very important action in order to keep the transportation balanced. Later on, motorcycles were invented which incorporated a motor engine instead of manual pedals.

Origin of Alternate Fuel Sources

alternate-fuel-vehicles

Electric vehicles or EVs were invented in the 1830’s which uses one or more electric motors. The rotary or linear motors propel the vehicle through the wheels. Linear motors are used by tracked vehicles such as trains and MRTs. There are several sources of energy used to move the vehicle like an on-board RESS or rechargeable energy storage system, batteries, on-board super capacitors and direct connection to energy-generating plants. Fuel cells and nuclear energy have also shown to be very viable in propelling vehicles.

Steam engines are another alternate fuel source which uses an external combustion engine or ECE. ECEs are less efficient compared to ICEs but proper configurations can be made for the fuel burner in order to emit very low amounts of carbon monoxide, nitrogen oxide and other harmful gases making it environmentally friendly in the process. Steam cars do have a problem when starting from cold leading to the development of flash boilers.

The Automobile

Automobiles are the most common type of vehicle. The majority of automobiles today are powered by gasoline or diesel engines. Automobiles use an internal combustion engine or ICE which can be highly polluting due to the constant burning of harmful gases. This type of vehicle has shown to be very powerful, convenient and aesthetic as well making it the most popular of all time.

Gasoline engine vehicles are lighter and able to work at optimum rotational speeds. The invention of the electric starter has boosted its popularity beating steam and electric cars in the process. Carburetor and fuel injection are some of the most useful discoveries in enhancing automobile performance.

There are various innovations in the engine allowing exhaust gases to be less harmful. Others combine efforts to minimize the greenhouse effect by reducing emissions to zero. Gasoline engines are capable of running with different ethanol concentrations. Some may run on 15%, 85% or even 100% ethanol. Fuel burn efficiency of gasoline engine vehicles are around 27%.

Diesel engine vehicles are more cost-effective compared to gasoline engine ones because of their 50% fuel burn efficiency. However, power and performance is also compromised due to less concentration of fuel. Diesel also releases exhaust gases into the atmosphere from soot particles. 100% biodiesel has been developed to improve the downside of these vehicles.

Other Transports

A train is a series of vehicles moving along a guided track or rail. A separate locomotive provides power to propel the entire train. Diesel or electricity is the usual energy source of trains while older versions were dominantly powered by steam engines. There are special kinds of trains with special tracks like rubber-tired underground, high-speed and monorails. Some trains can have more than one locomotive or coach.

A road train has a prime mover pulling one or more trailers. Trucks are the simpler version of this. Since the weight and maneuverability are a challenge, these vehicles often require several wheels for more control. Speed should also be watched meticulously to make travel as safe as possible. Diesel engines usually power big heavy trucks and road trains for fuel efficiency and power.

Other unique types of vehicles are amphibious vehicles and snowmobiles. Amphibians can run on both land and water making them very versatile. There are amphibious bicycles, cars, trucks and ATVs developed for passenger and official use.

The advantages provided by amphibians made them very useful for military operations. Snowmobiles are propelled by a built-in track made of Kevlar composite or rubber in order to effectively move through snow. These are also powered by a motor engine that consumes gas for fuel. Tanks use the same mechanism as snowmobiles by running on steel tracks.

Just thought you interest with other guide on : hybrid vehicles