职业技术教育 Case Study

什么是职业技术教育,其实很多人不了解，职业技术教育与职业教育和职业培训不同，是指对职业教育的技术化和工具化，当前我国高技能人才匮乏的一个原因就是对职业技术的认识严重不足。

中世纪的艺徒制只能适应手工作坊的生产，产业革命后需要大量熟练技术工人，各国纷纷制定法令，开办各种类型的习艺所，为贫民子弟提供接受技艺训练的场所。一些有识见的人士看到了职业技术教育不仅对于生产，而且 对于社会安定的重要作用，呼吁加强职业技术教育。如工业革命的中心英国，1562年英格兰《工厂法》要求在全国建立规范的学徒制度，马克斯韦伯曾高度评价 这种“中世纪就业已有过的理性的手工业学徒制度”，并将其归结为西方资本主义精神的产物。在经济发展、社会转型和社会问题层出不穷的背景下，一些社会人 士提出以学校教育防止犯罪的解决方案，要求富人关注穷人的教育，初等职业学校与其说是为了增进劳动技能，还不如说是灌输服从、守法的观念，成为社会教化和 控制的一种方式，目的在于使工人阶级乃至全社会都接受资本主义的价值观。这种学徒制度使教育与家庭分离，成为后来初等职业技术教育的重要基础。

职业教育是国家教育体系中与普通教育相提并论的教 育分支系统，是提高劳动者就业能力、促进劳动就业的重要途径，也是为不同性向和能力的学生提供发展途径，满足社会各方面教育需求的制度。职业技术教育不仅对经济发展有着明显促进作用，也是社会安定和谐的必要措施，职业教育与普通教育并驾齐驱的教育制度，应当是我国当前教育发展的重点。职业技术教育是工业化社会的产物，它的兴起既是经济发展的需要，也是社会安定的需要。

资料来源：北大青鸟

Electric Car - Nissan LEAF

The Nissan Leaf is a compact five-door hatchback electric car manufactured by Nissan and launched worldwide in December 2010.

What is LEAF?
"LEAF" stand for Leading, Environmentally friendly, Affordable, Family car.

Special Features?

The Nissan Leaf is Zero Emission Vehicles(ZEV). It produces no tailpipe pollution or greenhouse gas emissions and 100% dependence on electricity.

Battery Pack?
The Nissan Leaf loaded with 24 kWh lithium-ion battery produces 90kW and supplies power to the 80kW AC electric motor which produces 80kW (107 horsepower) and 280Nm of torque. The battery pack is expected to retain 70% to 80% of its capacity after 10 years but its actual lifespan depends on how often fast charging (440-volt) is used and also on environmental factors.

Performance?
LEAF has a top speed of over 150km/h. Unofficially, 0 to 97 km/h performance has been tested at 7.0 seconds.

How far can it go with one charge?
1. EPA LA4 test cycle: 160km per charge (standard)
2. Ideal driving conditions: 220km per charge
3. Highway driving in the summer: 112km per charge
*Travel range can be affected by climate, speed, driving style, cargo and topography

Recharging?
the Leaf can be charged overnight from a 200V power outlet in about 8 hours, or via a DC quick charger in under 30 minutes.

Price?
Japan ¥3.76 million (US$44,600)
United States US$32,780
United Kingdom GB£28,990 (US$44,800)
Malaysia To Be Announced (estimated RM 120,000)

Electric Car - Advantages and Disadvantages

With the price of oil soaring and gasoline prices rising as a result, the desire for alternative fuels is higher than ever. If you're thinking about purchasing a electric car, there are many things to consider. Below is a brief list of advantages and disadvantages ofbowning a electric car (Ev Car)

 















Advantages
Zero-emissions vehicle. The Ev is completely electric, it has no gasoline or diesel powered engine to supplement for power. Electric vehicles (EV's) utilize no fossil fuels, so there are no emissions whatsoever. As a result the environment will be cleaner with less smog and greenhouse gases.

Quiet ride. Since electric cars don't have conventional fossil fuel engines (which utilizes internal combustion for power), they run smoother and quieter. At low speeds, electric vehicles are virtually silent.

Electric cars are easy to assemble. The engine system for EV's is simple, EV engines have less parts, less moving parts which can translate to fewer visits to a garage for repairs over the life of the car. At the same time, EV car require less maintenance.

Electricity is readily available. Electricity is everywhere and easy to come by. Owners do not need to set up electricity stations on the corner to re-charge cars. It can be done at home. Almost 100 percent of EV car batteries can be recycled, which keeps old batteries from becoming a disposal problem.

Disadvantages
Limited traveling radius. One charge on a battery can take the car approximately 160km. Therefore if owner plan on traveling a long distance, they may be at the risk of the battery getting discharged. As such there are no battery charging stations available on all roads and highways.

Charging and cost. It takes 6-8 hours to fully recharge the battery. You can not expect to be ready to go in a few minutes after wearing down the battery. If owner live in an apartment or don't have a garage or a place where they can plug in to a 220 volt outlet, charging EV can be a problem. Your electric bill will probably increase as you have to draw power from your home electrical system to charge your car.

Less powerful. Electric cars cannot compete with gas powered cars in terms of speed and acceleration. Technology has not yet developed an electrical system as powerful as a gas powered vehicle.

Environment costs. Though the vehicle running on electricity does not produce pollution, the power plants producing electricity do produce pollution. The pollutants created by thermal power plants which burns fossil fuels to generate electricity are one of major source of air-pollution.

Electric Car - How it works

Inside an Electric Car

The heart of an electric car is the combination of:

• The electric motor
• The motor's controller
• The batteries

A simple DC controller connected to the batteries and the DC motor. If the driver floors the accelerator pedal, the controller delivers the full 96 volts from the batteries to the motor. If the driver take his/her foot off the accelerator, the controller delivers zero volts to the motor. For any setting in between, the controller "chops" the 96 volts thousands of times per second to create an average voltage somewhere between 0 and 96 volts.

The controller takes power from the batteries and delivers it to the motor. The accelerator pedal hooks to a pair of potentiometers (variable resistors), and these potentiometers provide the signal that tells the controller how much power it is supposed to deliver. The controller can deliver zero power (when the car is stopped), full power (when the driver floors the accelerator pedal), or any power level in between.
The controller normally dominates the scene when you open the hood, as you can see here:

The 300-volt, 50-kilowatt controller for this electric car is the box marked "U.S. Electricar."

In this car, the controller takes in 300 volts DC from the battery pack. It converts it into a maximum of 240 volts AC, three-phase, to send to the motor. It does this using very large transistors that rapidly turn the batteries' voltage on and off to create a sine wave.
When you push on the gas pedal, a cable from the pedal connects to these two potentiometers:

The potentiometers hook to the gas pedal and send a signal to the controller.

The signal from the potentiometers tells the controller how much power to deliver to the electric car's motor. There are two potentiometers for safety's sake. The controller reads both potentiometers and makes sure that their signals are equal. If they are not, then the controller does not operate. This arrangement guards against a situation where a potentiometer fails in the full-on position.

Heavy cables (on the left) connect the battery pack to the controller. In the middle is a very large on/off switch. The bundle of small wires on the right carries signals from thermometers located between the batteries, as well as power for fans that keep the batteries cool and ventilated.

The heavy wires entering and leaving the controller

The controller's job in a DC electric car is easy to understand. Let's assume that the battery pack contains 12 12-volt batteries, wired in series to create 144 volts. The controller takes in 144 volts DC, and delivers it to the motor in a controlled way.
The very simplest DC controller would be a big on/off switch wired to the accelerator pedal. When you push the pedal, it would turn the switch on, and when you take your foot off the pedal, it would turn it off. As the driver, you would have to push and release the accelerator to pulse the motor on and off to maintain a given speed.
Obviously, that sort of on/off approach would work but it would be a pain to drive, so the controller does the pulsing for you. The controller reads the setting of the accelerator pedal from the potentiometers and regulates the power accordingly. Let's say that you have the accelerator pushed halfway down. The controller reads that setting from the potentiometer and rapidly switches the power to the motor on and off so that it is on half the time and off half the time. If you have the accelerator pedal 25 percent of the way down, the controller pulses the power so it is on 25 percent of the time and off 75 percent of the time.
Most controllers pulse the power more than 15,000 times per second, in order to keep the pulsation outside the range of human hearing. The pulsed current causes the motor housing to vibrate at that frequency, so by pulsing at more than 15,000 cycles per second, the controller and motor are silent to human ears.

An AC controller hooks to an AC motor. Using six sets of power transistors, the controller takes in 300 volts DC and produces 240 volts AC, 3-phase.  The controller additionally provides a charging system for the batteries, and a DC-to-DC converter to recharge the 12-volt accessory battery.

In an AC controller, the job is a little more complicated, but it is the same idea. The controller creates three pseudo-sine waves. It does this by taking the DC voltage from the batteries and pulsing it on and off. In an AC controller, there is the additional need to reverse the polarity of the voltage 60 times a second. Therefore, you actually need six sets of transistors in an AC controller, while you need only one set in a DC controller. In the AC controller, for each phase you need one set of transistors to pulse the voltage and another set to reverse the polarity. You replicate that three times for the three phases -- six total sets of transistors.
Most DC controllers used in electric cars come from the electric forklift industry. The Hughes AC controller seen in the photo above is the same sort of AC controller used in the GM/Saturn EV-1 electric vehicle. It can deliver a maximum of 50,000 watts to the motor.

 Link: howstuffworks

Electric Car - Basic Knowledge

Electric cars are a variety of electric vehicle (EV); the term "electric vehicle" refers to any vehicle that uses electric motors for propulsion, while "electric car" generally refers to road-going automobiles powered by electricity.

Ev car are different from Hybrid car as we mentioned before. It is powered by an electric motor rather than a gasoline engine.It create less pollution than gasoline-powered cars, so they are an environmentally friendly alternative to gasoline-powered vehicles.

Under the hood, there are a lot of differences between gasoline and electric cars:

* The gasoline engine is replaced by an electric motor.
* The electric motor gets its power from a controller.
* The controller gets its power from an array of rechargeable batteries.

Electric vehicles use electricity stored on the car in batteries. Sometimes, 12 or 24 batteries, or more, are needed to power the car. Just like a remote-controlled, model electric car has an electric motor that turns the wheels and a battery to run that motor. When the batteries is exhausted, the car is usually plugged in into a special charging unit or plug right into a regular electrical wall outlet.

From the outside, you would probably have no idea that a car is electric because most of the electric cars are created by converting a gasoline-powered car, and in that case it is impossible to tell.

Hybrid Car - Improving Fuel Economy

Improving Fuel Economy
Besides a smaller, more efficient engine, today's hybrids use many other tricks to increase fuel efficiency. Some of those tricks will help any type of car get better mileage, and some only apply to a hybrid. To squeeze every last mile out of a gallon of gasoline, a hybrid car can:

• Recover energy and store it in the battery - Whenever you step on the brake pedal in your car, you are removing energy from the car. The faster a car is going, the more kinetic energy it has. The brakes of a car remove this energy and dissipate it in the form of heat. A hybrid car can capture some of this energy and store it in the battery to use later. It does this by using "regenerative braking." That is, instead of just using the brakes to stop the car, the electric motor that drives the hybrid can also slow the car. In this mode, the electric motor acts as a generator and charges the batteries while the car is slowing down.

• Sometimes shut off the engine - A hybrid car does not need to rely on the gasoline engine all of the time because it has an alternate power source -- the electric motor and batteries. So the hybrid car can sometimes turn off the gasoline engine, for example when the vehicle is stopped at a red light.

• Use advanced aerodynamics to reduce drag - When you are driving on the freeway, most of the work your engine does goes into pushing the car through the air. This force is known as aerodynamic drag. This drag force can be reduced in a variety of ways. One sure way is to reduce the frontal area of the car. Think of how a big SUV has to push a much greater area through the air than a tiny sports car.Reducing disturbances around objects that stick out from the car or eliminating them altogether can also help to improve the aerodynamics. For example, covers over the wheel housings smooth the airflow and reduce drag. And sometimes, mirrors are replaced with small cameras.

• Use low-rolling resistance tires - The tires on most cars are optimized to give a smooth ride, minimize noise, and provide good traction in a variety of weather conditions. But they are rarely optimized for efficiency. In fact, the tires cause a surprising amount of drag while you are driving. Hybrid cars use special tires that are both stiffer and inflated to a higher pressure than conventional tires. The result is that they cause about half the drag of regular tires.

• Use lightweight materials - Reducing the overall weight of a car is one easy way to increase the mileage. A lighter vehicle uses less energy each time you accelerate or drive up a hill. Composite materials like carbon fiber or lightweight metals like aluminum and magnesium can be used to reduce weight.

 Sources: http://auto.howstuffworks.com/hybrid-car4.htm

Hybrid Car - 3 Reasons to go for HYBRID car

1: Competitive Prices and tax Incentives

Hybrid cars are generally priced slightly higher than their gasoline-powered counterparts. The extra effort necessary to create the technology that combines both gas and electric power makes them more expensive. However, many automakers are pushing to produce more affordable hybrids for drivers looking to take the plunge.

when the Budget 2011 was announced, the Malaysian government lowered the duties for hybrid vehicles below 2,000cc of displacement to 0% for both excise and import duty. The Toyota Prius is priced at RM139,900 in the Peninsular Malaysia and RM141,500 in Sabah and Sarawak after drop of about RM35,000 in Peninsular Malaysia from the previous price of RM175,000. At the same time, the new launched Honda Insight became the first mass-produced hybrid car to cost less than $100,000, as the most basic model goes for $98,000. For drivers who don't worry too much about extra features, it's now possible to purchase any one of a variety of affordable hybrids.

2: Environmental benefits

Burning fossil fuels, like the gasoline burned in an internal combustion engine, releases carbon dioxide (CO2) and other greenhouse gases into the atmosphere, where they collect and warm the planet. As the global climate changes, significant consequences can arise, including elevated temperatures, rising sea levels, freshwater scarcity and crop failures.

Hybrid Car significantly reduced the emissions of C02 into environment. Fewer and cleaner emissions is a major reason why hybrid cars are popularly known as 'green' cars. Reduced emission ensures lower pollution levels, something which is highly necessary in today's times.Another way in which hybrid cars benefit the environment is that they help in lowering noise pollution levels. Hybrid car engines go about churning the required amount of horsepower without any excessive roaring. When switched onto electric power mode, these cars are virtually silent when in operation.

3: Financial Benefits

Improved fuel efficiency is one of the other significant advantages of owning a hybrid vehicle. When it comes to mileage, hybrid cars outperform regular gasoline-powered cars by approximately 20 to 30 percent. That is quite a significant number in today's fuel scenario. Shutting off the engine when not required, re-using the energy spent in braking, advanced aerodynamics, better-designed tires, etc. are some of the other advantages that hybrid cars have to offer. Usage of hybrid cars translates into added savings. As they offer better fuel economy, you end up spending lesser on gasoline, thereby ensuring a few hundred dollars' worth savings every year.

Hybrid Car - Parallel Hybrid or Series Hybrid

All hybrids have in common is the ability to generate electric current, store it in a large battery, and use that current to help drive the car. Hybrids capture electrical energy produced by a regenerative braking system, and their engines can power a generator, too.

A series hybrid is very similar to a parallel hybrid. Both have the advantage of increasing fuel efficiency compared with conventional gasoline-powered vehicles, and giving the driver greater range than an all-electric vehicle. Both types of hybrids are reliant on large battery packs to store energy and both types may use additional technologies like regenerative braking to capture energy that would otherwise go to waste.

However, the mechanisms are quite different:

Parallel Hybrid

With a parallel hybrid electric vehicle, both the engine and the electric motor generate the power that drives the wheels. The addition of computer controls and and a transmission allow these components to work together. Parallel hybrids can use a smaller battery pack and therefore rely mainly 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, much like an alternator in conventional cars.

Series Hybrid

This is the simplest hybrid configuration. In a series hybrid, the electric motor is is the only means of providing power to get your wheels turning. The motor receives electric power from either the battery pack or from a generator run by a gasoline engine. A computer determines how much of the power comes from the battery or the engine/generator set. Both the engine/generator and regenerative braking recharge the battery pack. The engine is typically smaller in a series drivetrain because it only has to meet average driving power demands; the battery pack is generally more powerful than the one in parallel hybrids in order to provide remaining peak driving power needs. This larger battery and motor, along with the generator, add to the cost, making series hybrids more expensive than parallel hybrids.

Comparison:

• The series hybrid can be charged off of the power grid, for convenience & much cheaper operation (< 20% of the cost of running on gas) with no loss of performance (except range), otherwise use the onboard generator, The parallel hybrid may be able to run off the power grid if you expand the battery pack, but with reduced performance.

• The series hybrid is much simpler in design & maintenance than the parallel hybrid. It does not need a clutch or transmission, no oil changes, spark plugs, fuel/oil filters except on the separate generator which can be removed or replaced easily. It does not need the complex control / interface between the gas engine & electric motor.

• The series hybrid has better acceleration due to the superiority of the much larger electric motor to the gas motor in this respect.

• The generator engine on the series hybrid can be much smaller, simpler and more efficient than on the parallel hybrid.

Hybrid Car - Basic knowledge

Depleting fuel resources and awareness about the environment issues in the late 1990s caused automobile manufacturers started to explore alternative forms of transportation, including vehicles powered by hybrid motor. Neither technology is particularly novel, yet it has a place in the future of transportation.

A hybrid car is a car that uses two or more distinct power sources to move the car. The term most commonly refers to hybrid electric vehicles (HEVs). It combine an internal combustion engines (generally gasoline or Diesel engines, powered by a variety of fuels) and electric batteries to power electric motors.

A hybrid electric vehicle produces far less toxic emissions then standard gasoline only vehicles. The Toyota Prius, for example, has 90% less emissions then a comparably sized conventional car. The use of the electric motor for propulsion in low speed environments and the technology that allows a HEV to turn off the combustion engine when idling greatly reduces the emissions from the vehicle. Hybrid electric vehicles use smaller engines than conventional automobiles and have less moving parts that are prone to wearing out and creating waste. The most attractive environmental advantage to an HEV is the increased fuel efficiency of these types of vehicles. For most consumers, this is the most important advantage of all during times of high fuel prices and the environmental benefit of the vehicle consuming less fossil fuel often goes unrecognized.

Engine: More efficient than traditional engine found in most cars

Electric motor: Uses magnets to produce output

Battery: Charged by engine via generator when cruising, or electric motor when braking

Power split device: Allows engine and motor to be used independently, or together

Braking system: Energy from braking recharges battery, by using motor as generator

Inverter: Converts DC power from battery to AC power for motor

Toyota was the first to make a broadly accepted hybrid vehicle with the Toyota Prius in 1998. By early 2010, the Prius global cumulative sales were estimated at 1.6 million units. The 2010 Prius has an estimated U.S. Environmental Protection Agency combined fuel economy cycle of 50 miles per US gallon (4.7 L/100 km).

KLIMS 2010 Proton Saga EV

Recently we have been talking about GREEN technology. GREEN tech is  important to conserve the natural environment and resources, and to curb the negative impacts of human involvement. So, minimising the impact cars have on environment is a top priority. The Automobile industries sectors is now doing their part in mitigating the effects of environmental threat to mankind by developing HYBRID car or Ev. It is not only to reduce emissions from the vehicles, but to make the entire life-cycle of a car more environmentally friendly to maintain a sustainable environment for future generation.

As the leader of local automobiles industry, Proton through its Engineering Division has initiated the electric vehicle (EV) project in November 2008 when a team of technologist was dispatched to Lotus Engineering UK to develop two units of electric vehicles.

In conjunction with KLIMS 2010, Proton has revealed its first generation of concept Electric Vehicle (Ev) name Proton Saga Ev concept. Sage Ev concept can be viewed as Proton’s long term strategy of acquiring and commercializing the technology as indicated in Proton’s Technology Roadmap. This is also part of the initiative to support the National Green Technology Policy that was implemented by the goverment to chart the nation’s development in green technology as the new driver of economic growth.

The primary difference between a HYBRID car and an electric car (Ev) is that the hybrid car derives some of its power from a conventional gasoline engine. On the other hand, a true electric car gets all of its power from electrical sources, and thereby is a completely non-polluting zero-emission vehicle (ZEV).

 

EV Saga Specification:

Engine:
Azure Dynamics AC24LS 5.5 kW 4-pole, three-phase air-cooled AC electric motor (and corresponding DMOC445 digital motor controller) that can spin up to a maximum of 11,000 rpm, and which offers 47 kW (63 hp) of peak power and 92 Nm of max torque, working with a single-gear transmission and a 15 kWh, 50Ah lithium-ion battery.

Battery:
The battery consists of 8 separate modules, and each module is made up of 40 cells weighs in at 240 kg. It doesn’t completely eat up the boot space of the car however it is just 150 kg more than a standard Saga, with the battery being the hefty lad. Off a normal 240V point, the battery takes seven to eight hours to charge fully, though it can be fast charged if the need arises.

Performance
The EV Saga has a top speed of 125 kph and offers a 160 km range (in NEDC cycle mode), with a 0-100 kph time of 14.5 seconds.