ENERGY EFFIFIENCY The diagram above shows typical energy uses and losses in a vehicle.
DRIVELINE LOSSES – 5.6%1. Energy is lost in the transmission and other parts of the driveline2. Technologies such as Automated manual transmission (AMT) and Continuous variable transmission (CVT) are used to reduce the losses
AUTOMATED TRANSMISSIONSYSTEMAutomated manual transmissions combine the best features of manual and automatic transmissions. AMT operates similarly to a manual transmission except that it does not require clutch actuation or shifting by the driver
AMT CONTD… Automatic shifting is controlled electronically (shift-by-wire) and performed by a hydraulic system or electric motor Efficiency improvement: 7%
CONTINUOUSLY VARIABLETRANSMISSION (CVT) Rather than using gears, the CVTs in currently available vehicles utilize a pair of variable- diameter pulleys connected by a belt or chain that can produce an infinite number of engine/wheel speed ratios
CVT CONTD.. Advantages -Seamless acceleration without the jerk or jolt from changing gears - No frequent downshifting or "gear hunting" on hills -Better fuel efficiency
IDLING LOSSES – 17.2%1. In urban driving, significant energy is lost to idling at stop lights or in traffic2. Technologies such as Integrated starter/generator (ISG) turns to reduce losses automatically by turning the engine off when vehicle is stopped and starts automatically when accelerator is pressed
ISG SYSTEMS These systems automatically turn the engine off when the vehicle comes to a stop and restart it instantaneously when the accelerator is pressed so that fuel isnt wasted for idling. In addition, regenerative braking is often used to convert mechanical energy lost in braking into electricity, which is stored in a battery and used to power the automatic starter.
ACCESSORIES – 2.2% Air conditioning, power steering, windshield wipers, and other accessories use energy generated from the engine. Fuel economy improvements of up to 1% may be achievable with more efficient alternator systems and power steering systems
OVERCOMING INERTIA;BRAKING LOSSES– 5.8% move forward, a vehicles drivetrain must provide enough energy to overcome the vehicles inertia, which is directly related to its weight. The less a vehicle weighs, the less energy it takes to move it. Weight can be reduced by using lightweight materials and lighter-weight technologies
AERODYNAMIC DRAG – 2.6% A vehicle must expend energy to move air out of the way as it goes down the road—less energy at lower speeds and progressively more as speed increases. Drag is directly related to the vehicles shape
CONTD.. Smoother vehicle shapes have already reduced drag significantly, but further reductions of 20- 30% are possible
ROLLING RESISTANCE – 4.2% Rolling resistance is a measure of the force necessary to move the tire forward and is directly proportional to the weight of the load supported by the tire A variety of new technologies can be used to reduce rolling resistance, including improved tire tread and shoulder designs and materials used in the tire belt and traction surfaces
CONTD.. For passenger cars, a 5-7% reduction in rolling resistance increases fuel efficiency by 1% However, these improvements must be balanced against traction and noise
AUTOMOTIVE NAVIGATION SYSTEM An automotive navigation system is a satellite navigation system designed for use in automobiles It typically uses a GPS navigation device to acquire position data to locate the user on a road in the units map database.
GPS CONTD.. Using the road database, the unit can give directions to other locations along roads also in its database. Dead reckoning using distance data from sensors attached to the drivetrain, a gyroscope and an accelerometer can be used for greater reliability, as GPS signal loss and/or multipath can occur due to urban canyons or tunnels.
ANTI-LOCK BRAKING SYSTEM1. An anti-lock braking system, or ABS is a safety system which prevents the wheels on a motor vehicle from locking up (or ceasing to rotate) while braking.2. A rotating road wheel allows the driver to maintain steering control under heavy braking by preventing a skid and allowing the wheel to continue interacting tractively with the road surface as directed by driver steering inputs
CONTD.. While ABS offers improved vehicle control, and may decrease stopping distances on dry and especially slippery surfaces, it can also increase braking distance on loose surfaces such as snow and gravel
OPERATION OF AN ABS The anti-lock brake controller is also known as the CAB (Controller Anti-lock Brake). A typical ABS is composed of a central electronic control unit (ECU), four wheel speed sensors — one for each wheel — and two or more hydraulic valves within the brake hydraulics
CONTD.. The ECU constantly monitors the rotational speed of each wheel, and when it detects a wheel rotating significantly slower than the others — a condition indicative of impending wheel lock — it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force
CONTD.. The wheel then turns faster; when the ECU detects it is turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied and the wheel slows This process is repeated continuously, and can be detected by the driver via brake pedal pulsation. A typical anti-lock system can apply and release braking pressure up to 20 times a second
AIR BAGS Like seat belts, the concept of the airbag -- a soft pillow to land against in a crash -- has been around for many years To date, statistics show that airbags reduce the risk of dying in a direct frontal crash by about 30 percent.
WORKING1. The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door2. The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip
WORKING3.The airbags inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag
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