Formula SAE was conceived in 1978 by the Society of Automotive Engineers and has steadily grown from a just handful of US teams to 600 teams worldwide. The best engineering institutions compete against one another with one goal in mind: To be the best in the world.
Students come together to design, build, and race a Formula-style race car. A new car is created every year. Team members think constantly about the improvements on the car, and what will make the current year’s car outperform the last. But there is no way yet to bypass the laws of thermodynamics, drag coefficients and tire slip angles and most of all making a FSAE car is not a personal project, it’s a multidisciplinary effort which requires experts from each discipline to sit together, brainstorm and find best engineering solution possible, hence in that regard Pravega Racing had its first design review of the current season on the 10th of February,2013 where each department revealed their goal for this season and also the approach they have adopted to ensure that the goal is achieved so as to compliment the extremely tight schedule they have to follow in order to complete the car in time.

Apart from the intense technical review where the entire team discussed, argued upon and polished every design and technical decision down to the tee, another very interesting and exceptionally fruitful discussion was when the entire team sat together to solve the biggest problem of them all, how well does what we do technically fit the bigger picture? There has to be a vision that the team is following, something that the entire process of designing, manufacturing, testing and racing leads to.
Without that image all those efforts would be nothing more than a drop in the ocean but with this vision in mind, truly amazing things can be given shape. And after an exhausting session of to and fro the solution took form in front of them, in true engineering fashion, on a whiteboard at two in the morning.

Gallery: 

The post Pravega Racing Design Review – Engineering The Future appeared first on AutoSpace.

Hmmm… but What is Drafting?

The practice of two or more cars running nose to tail to create more speed for the group is called drafting. The car on the tail is known as car in the draft. Race cars use drafting to gain speed and to go faster by having less drag. The beginning of the technique of drafting is said to came from NASCAR racing. Racing legend Junior Johnson is acknowledged as the first driver to use drafting as a competitive tactic. In 1960, Johnson was driving an under powered Chevy with several dominant Pontiac cars on the track at that time. He noticed the while keeping his car behind the car of Bobby Johns who was driving one of the Pontiac, he could keep pace with the bigger and faster vehicles. This was the beginning of the technique of drafting.

In that race, Johns reportedly was in a drafting position with another driver and the lower pressure from the slipstream was so intense it sucked Johns’ rear window out of his car. Johns spun out and crashed and Junior Johnson won the race.

Amazing!, but what is the Physics behind drafting?
Logic behind the drafting is pretty simple but first we need to understand, how aerodynamics offers resistance or drag?
There are two types of drag – Friction and Pressure. Friction drag is due the friction between air and the surface of the object which means more the streamline object lesser will be the friction drag where as pressure drag is due to pressure difference between front and back of the car, as the air flowing over a car leaves a low pressure region at the back relative to the front. This pressure difference multiplied by the effective area of the car gives a force opposite to the direction of motion of the car which is known as pressure drag.

Now the above mentioned physics is exploited while drafting. As the car in the front (as shown in the figure) moves, it create a envelop of very less amount of air behind it thus reducing the friction drag for the cars behind. Also as the lead car moves it creates a low pressure region or say partial vacuum, at the back which sucks the car at the back to the front thus reducing pressure drag too and allowing it to gain more speed. The technique of drafting is beneficial not only for the car at the back but also in the front. Collectively both cars can move faster than a single car on the side ways and that is because car at the back of lead car reduces the low pressure area behind the lead car and thus reducing pressure drag.

Here is a video to help you understand drafting more easily:

Is drafting phenomenon limited to race cars?

No, the concept of drafting existed in nature way before humans could notice it.
Have you seen birds moving in V formation?  The V formation greatly boosts the efficiency and range of flying birds, particularly over long migratory routes.  In a V formation of 25 birds, each bird can achieve a reduction of drag by up to 65% and as a result increase their range by 71%.

NASA also exploits the concept of reducing friction drag in a little different way. Notice the front of the space shuttle as shown. You could find that on one hand where most of the supersonic aircraft have a very streamlined nose, space shuttle have a very blunt nose. But why?
Since if shuttle have streamline nose the air will flow around the body. Now as the high speed air flows around the surface, it tends to heat the surface. As space shuttle re-enters the earth atmosphere, the resistance offered by air is so high that it can heat the surface of  shuttle above 3000 degree Celsius and can result in complete meltdown of wings. So what NASA’s engineers did is that they designed the shuttle with a blunt nose.

Blunt nose creates a envelop of low air density around the aircraft or deflecting  the air away from the aircraft (as shown) and thus reducing air friction and hence the temperature of the wings. So, you can say that wings are in draft to nose :P.

That’s it, this is all about drafting. So, whenever you jump on highway with your car, try to feel this effect, but don’t get too close because your journey may end up in the hospital.

Also, did you seen any other examples of drafting? Do let me know in comments!

The post Physics Behind Race Car Drafting appeared first on AutoSpace.

KERS stands for ‘Kinetic Energy Recovery System’ and in short its main aim is to harness the kinetic energy of the vehicle (which is lost in form of heat under braking) , stores it in some other form energies(like electrical or rotational ) that can boost acceleration by pressing a button on the steering wheel under acceleration. Now a days this system is not very common in road-cars but it is extensively used in racecars. Actually the whole idea of  harnessing the kinetic energy was invented way back in 50s when physicist Richard Feynman proposed an idea of storing vehicles kinetic energy by the use of flywheel but no serious attempts were made in field of energy recovery until 2006 when the FIA, F1’s governing body, elected to allow teams to integrate Kinetic Energy Recovery Systems (KERS) into their vehicles starting in the 2009 racing season. And this rule forced the engineers to brainstorm and come up with an efficient yet lite weight KERS system.

Okay, what are the different type of energy harnessing techniques ?

Well, working of KERS mainly depends upon the type of energy harnessing  method they use. There are several different approaches for harnessing energy which are mentioned below-

• Mechanical Recovery ( By the use of flywheel which stores kinetic energy of the vehicle in form of rotational energy)
• Electrical Recovery (By the use of batteries or ultra-capacitors to store K.E. in form of electrical energy)
• Electromechanical Recovery( By the use of both flywheel and electric motor)
• Hydraulic recovery (By conducting pressurized hydraulic fluid into an accumulator during deceleration, then conducting it back into the drive system during acceleration)

Right then..could you explain to me  in detail about each energy recovery system…?

Sure. Well, the anatomy and working of the KERS system depends upon its approach of  recovery. So here we go..

Flywheel hybrid systems (KERS):

One of the first companies to put up their finance and faith in field of energy recovery and specially Mechanical energy recovery  was Flybrid systems. And the story of formation of this company is as interesting as its name. The flybrid systems was co- founded by Hilton who was drivetrain engineer at Renault F1 and with his colleague Doug Cross who was design manager in the same team.

‘We sat down in the pub and said this is how big a job it is,’ Hilton recalls. ‘We worked out how much we thought it would cost to get to the point of a running demonstrator on an engine dyno – we thought we would have to get that far to sell it to anybody – and we discussed whether we had enough finance between us, and agreed we did.’ And so Flybrid Systems was born. And the name was derived from formula given below:

Flywheel + Hybrid= Flybrid

Now let’s see the working of flywheel based energy recovery system. The system comprises a flywheel connected by a continuously variable transmission [CVT] to the drivetrain. If you move the CVT toward a gear ratio that would speed the flywheel up it stores energy. Conversely, if you move toward a ratio that would slow it down then it releases energy. Finally, a clutch separates the drive if the revs move beyond the limits of the system. But Flybrid’s innovations also address the need to create sufficient power storage density in a unit small enough and light enough for use in F1. To achieve this they upped the speed of the flywheel massively to 64,500rpm, which allows a smaller, lighter flywheel but also means it has to be contained in a very robust structure in case of failure. And to avoid the heat produce due to air friction at such a high speed they decided to put the flywheel in vacuum casing.

But at this point of time you might think, how can we get the same amount of energy by decreasing the mass and increasing the rotation of the flywheel?

Well, as we know that rotational energy of the spinning wheel is given by-

where,

•   I is the moment of inertia of of the flywheel and

•    is the Angular velocity

Also moment of Inertia of inertia of the disc about the z axis as shown in figure is given by

so what what we conclude from the above formulas is that rotational energy is directly proportional to mass and squared times the angular velocity. So if we decrease the mass to half the rotational energy becomes half meanwhile if we double the angular velocity, rotational energy becomes four times so over all if decrease the mass to half and double the  , we get twice the energy as we are getting previously.

So that’s why they prefer a lite flywheel weighing of around 5 kg  but such a high rotational speed. Still finding it difficult to understand?
Have a look at this video…

And that’s all we have on mechanical recovery and if you still feel their is still something I left out, or unexplained, feel free to kick my butt ( let me know! ) . Now lets see the fundamentals of electrical recovery, shall we

Electrical Hybrid (KERS):

Most of the F1 teams use this KERS to recover energy as the mechanical recovery have some packaging issues. In essence a electrical KERS systems is simple, you need a component for generating the power, one for storing it and another to control it all. Thus electrical KERS systems have three main components: The MGU, the PCU and the batteries. All component are labeled in the figure given below:

A. MGU (Motor Generator unit)

Mounted to the front of the engine, this is driven off a gear at the front of the crankshaft. Working in two modes, the MGU both creates the power for the batteries when the car is braking, then return the power from the batteries to add power directly to the engine, when the KERS button is deployed.

B.PCU (Power Control Unit)

Typically mounted in the sidepod this black box of electronics served two purposes, firstly to invert & control the switching of current from the batteries to the MGU and secondly to monitor the status of the individual cells with the battery.

C. Batteries

The batteries are the arrays of lithium-ion cells and approximately same as your cell phone batteries. Made up of around 40 individual cells, these batteries would last two races before being recycled. Being charged and discharged repeatedly during a lap, the batteries would run very hot and needed cooling, this mainly took the form of oil or water cooling, and again McLarens example had them pack water cooled with its own pump and radiator.

So this was all about setup of  Electrical hybrid KERS, now lets see how it works?
When driver applies the break, some part its K.E. is converted into electrical energy by the help MGU, as the MGU unit act as a generator. This electrical energy is stored into the batteries via PCU which monitors the amount of energy harnessed by KERS system as FIA has restricted on the amount of energy that could be re-used, only 400kJ could be stored, which when used for 6.7s per lap, the car gained some 80hp. So when driver presses the button electrical energy which is stored in the batteries is again converted into mechanical energy by the help of MGU which act as a electrical motor this time. As of 2014(F1), the power capacity of the KERS units will increase from 60 kilowatts (80 bhp) to 120 kilowatts (160 bhp). This will be to balance the sport’s move from 2.4 litre V8 engines to 1.6 litre V6 engines. You can better understand the working of the Electrical KERS by watching this video:

Electromechanical KERS:

This type of KERS came into discussion when Williams (F1 team) suggested a recovery system based on both fly wheel and electrical motor or say MGU (Motor Generator Unit). In this system, when driver applies the break, some part of vehicles K.E. is converted into electrical energy by the help of MGU now this electrical energy is passed to another MGU which act as a motor at that time and speeds up the flywheel attach to it to a very high 70,000 RPM. Now when driver presses the button on his steering, the rotational energy of the fly wheel is converted back into electrical energy by the help of  MGU and that electrical energy is used by another MGU(acting as a motor) which speeds up the crankshaft and hence the whole car. The above system is explained in the following video…

So that was all about the electrical, mechanical and electromechanical KERS, now lets move onto the last type of KERS  i.e. Hydraulic.

Hydraulic KERS:

A hydraulic KERS uses a pump in place of the MGU and an accumulator in place of the batteries. So when driver applies the brake the the rotational energy is harnessed by the pump as it pumps the fluid into the high pressure accumulator from the fluid reservoir. Now when driver pushes the KERS button the high pressure fluid flows from high pressure accumulator to the pump(which now act as a hydraulic motor) and speeds up the vehicle. Hydraulic accumulators are already used in heavy industry to provide back up in the event of failure to conventional pumped systems. Using filament wound carbon fibre casing, an accumulator of sufficient capacity could be made light enough to fit into the car. McLaren(F1) had prepared just such an energy recovery system back on the late 90s, but it was banned before it could race (low FIA cap on energy storage). The video attached below, shows you the working of Hydraulic hybrid vehicle(HHV) who’s working is very close to the working of Hydraulic KERS used for racing purpose like F1…

The post Tech Talk: KERS appeared first on AutoSpace.

In the olden days, drivers had to rely on their skills to prevent the drive wheels from spinning out of control on slippery pavements. Now however, most of the actions of drivers are implemented via computer controls; which means that now, even an amateur driver can very easily and swiftly maneuver on slippery tarmacs, under a relatively high acceleration.

Another interesting fact is that many German vehicle manufacturers call traction control by its original German name: ASR traction control.

ASR stands for “Acceleration Slip Regulation.”  I’m guessing not many of you will not be familiar with this term.

First of all, What is traction?

Traction is simply the force of friction between the drive wheels treads and the tarmac. It is important to be able to compute the traction, because if the propulsive force exerted by the wheel is greater than the wheel’s traction, the wheel will skid, and the car may “spin out”.

Okay, But when do traction control system kicks in?

Now, here’s a situation: suppose you are driving on a steep hill and the tarmac is covered with snow. Now, due to some reason you are forced to stopyour car which is still on the steep hill! If you have ever faced this situation you know what I’m talking about. As the gravity is pulling car backwards and engine is twisting the wheel to move forward against the slippery ice, the wheels often start spinning wildly as the traction (or the adhesive force) between rubber and tarmac is very less. It is at that very(frightful) moment when traction control system kicks in to accelerate the car swiftly without slipping.

Still finding it difficult to visualise? watch this:

This system also comes into action when you are racing with tonnes of horsepower at your foot. At the start of a  race, you might thrust your foot on full throttle to get a speedy start. Instead what happens is, due to enormous horsepower coming onto the wheels and due to the car’s inertia, you often end up with a couple of wildly smoking wheels without moving an inch forward.

I got it but how does it works?

Traction control works at the opposite end of the scale from ABS — dealing with acceleration rather than deceleration. Traction-control systems utilize the same wheel-speed sensors employed by the antilock braking system. By adding modules and sensors, the system can be expanded to include these newer technologies. The speed sensor of ABS provides the feed of rotation speed of all four wheels, to the computing module of traction control system. When system senses that one or more wheels are moving with different rotational speed relatively, it pumps the breaks to control the slip and if necessary it also reduce the engine power by reducing the amount of fuel or charge.

In the case of traction control, the basic ABS system — as well as other components in the vehicle — requires some modification. To begin with, the old-style accelerator cable is typically replaced by an electronic drive-by-wire connection (although some older systems still use a mechanical accelerator cable), meaning the mechanical hook-up between the accelerator pedal and the throttle ceases to exist. Instead, a sensor converts the position of the accelerator pedal into an electrical signal, which the control unit (similar to the one used in ABS) uses to generate a control voltage. The standard ABS hydraulic modulator is also expanded to include a traction control component.

In short, with the help of sensors & programming, the rotation speed of the wheels are controlled(by the computer and not the driver) and optimized to maximize traction, when required.

Okay one last thing, does traction control system have the ability to increase traction?

Nope, many people misguidedly believe that traction control will prevent their vehicle from getting stuck in the snow or has ability to increase the traction. This couldn’t be true, it just attempts to prevent a vehicle’s wheels from slipping dangerously.

The post Tech Talk: Traction Control System appeared first on AutoSpace.

Giotto Bizzarrini

Giotto Bizzarrini , who was once a chief engineer in Ferrari around the 1950s, is the father of  Murciélago’s V12 Engine. I used the word ‘father’ due to it’s current relevance and significane. In reality, Giotto did not design the V12 engine of  Murciélago himself, rather he designed the 3.5 liter 60° V12 for Lamborghini 350 GTV, and with minor modifications and improvements, the very same engine (in 6.5 litre form) has been adopted as power plant for Lamborghini Murciélago LP 640.

When the 3,464 cubic centimetres (211.4 cu in) prototype was tested in 1963, it was able to produce 370 brake horsepower (276 kW; 375 PS) at 9,000 revolutions per minute (rpm) – a figure of almost 107 brake horsepower (80 kW; 108 PS) per litre, and marginally unprecedented at the time. Bizzarrini famously insisted that the engine was mechanically capable of reaching an astonishing 400 brake horsepower (298 kW; 406 PS) at 11,000 rpm with an uprated fuel system.

Since Lamborghini had no further plans for the original 350 GTV beyond a show-piece,  he had the engine bay ballasted with bricks and kept the bonnet shut throughout the Turin Auto Show. This incomplete show car was also short of brake calipers, foot pedals, and windshield wipers.However, ironically Lamborghini 350 GTV ended up as a mere ‘show-only’ car. Ferruccio Lamborghini was dissatisfied with several design features of the 350 GTV, and also with the state of tune of the engine. Ferruccio commissioned Carrozzeria Touring to redesign the car to be more practical and had the engine detuned to 270 brake horsepower (201 kW; 274 PS) at 6,500 rpm for use in the production car. The resultant new body and retuned engine resulted in the first production Lamborghini, the 350 GT.

It has now been 4 decades since Bizzarrini invented the engine. Yet due to it’s technical splendor, it has inspired engineers at Lamborghini even now to use it’s slightly modified big brother in their latest automobile invention, approximately just as it was.

The post Did You Know: Who Is The Father Of Murciélago’s V12 Engine? appeared first on AutoSpace.

The Buffalo, built by Force Protection Inc., is the largest of its fleet of MRAP vehicles. Classified as a category III protected vehicle, the Buffalo is officially designated as an MPRC (Mine Protected Route Clearing) vehicle, and is specifically designed to patrol roads and identify and either defeat, disarm, or remove mines and IEDs (improvised explosive devices).

Protection

The armor package provided by the Buffalo provides all round coverage against 7.62mm ammunition (the glass is 7.62mm multi-strike resistant.)  Ballistic protection is provided for the radiator, tires, battery compartment, fuel tanks, engine and transmission.  The V-shaped hull is specifically designed to redirect the blast out and away from the vehicle’s passenger area.  While the explosion may disable the vehicle, its passengers will not be injured, and the vehicle can be recovered and repaired. The Buffalo uses steel wheels and disc rollers which allow the vehicle to be driven over and detonate anti-personnel mines without sustaining damage.

As a result, unusually large numbers of mines can be neutralized in a short period of time.  In a recent incident that involved a Buffalo vehicle which ran over an anti-tank mine, the blast tore off a wheel and destroyed an axle on the vehicle. There were no casualties to the crew inside the Buffalo and the vehicle maintained its mobility and drove itself out of the minefield. It was repaired overnight and was back in operation the following day.

Vehicle details

Buffalo as Bonecrusher

The Buffalo has a Mack ASET AI-400 diesel engine that makes 450 hp and a whopping 1,450 lb-ft of torque. It’s matched to an Allison HD-4560P five-speed auto transmission. It can also run on the JP-8 jet fuel. The suspension consists of a Fabco SDA 2300 23,000-pound drive steer axle, while 50,000-pound (combined) Mack tandem axles are in back; air brakes provide the stop. The Buffalo runs on 1600R20 XZL Michelin rubber. It’s 117 inches tall, 97 inches wide, and 323 inches long, with a curb weight of 45,320 pounds. The approach and departure angles are 40 and 45 degrees, respectively, with 16 inches of ground clearance under the front axle, and 20 inches under the transfer case cover. The high-tech Buffalo has been engineered specifically to be repaired in the field.

The Buffalo is equipped with a hydraulically-powered articulated “claw” operated remotely from within the vehicle, which can be used to dig, extract, and remove objects in the soil without exposing the vehicle’s crew.

Armament

The Buffalo is equipped with a single, remotely operated roof mounted weapon station.  This station can accommodate a single machine gun (either M2 .50 caliber, M249 5.56mm, or M240 series 7.62mm) or the Mk. 19 40mm automatic grenade launcher.

Video:

The post Buffalo – a.k.a – The BoneCrusher appeared first on AutoSpace.

Nope! no big deal.  Just Click here to get the basics of idea of a four stroke engine. Now as you are moving on I think you have enough idea of “How a engine works”. So let’s begin.

If you are a petrol-head I can bet you are not hearing “Variable Valve Timing (VVT)” for the first time. But ever wondered How this system works? How this system affect’s the performance of car equipped with this technology? How a engine lash with VVT is different from a common engines?

When I heard about this technology I was a kind of stunned and by now I assume so you are, but now its time to unwrap the mystery of VVT.

In Theory

As you know, valves activate the breathing of engine. The timing of breathing, that is, the timing of air intake and exhaust, is defined by the shape and phase angle of cams. To optimise the breathing, engine requires different valve timing at different speed. When rev increases, the duration of intake and exhaust stroke decreases so that fresh air becomes not fast enough to enter the combustion chamber, while exhaust gas becomes not fast enough to leave the combustion chamber. Therefore, the best solution is to open the inlet valves earlier and close the exhaust valves later. In other words, the Overlapping between intake period and exhaust period should be increased as rev increases.

Previously a engine without VVT is set with best compromising time. For example, a pickup truck may adopt less overlapping for the benefits of low speed output. A racing engine may adopt considerable overlapping for high speed power. An ordinary sedan may adopt valve timing optimised for mid-range so that both low-speed drivability and high-speed output will not be sacrificed too much. No matter which one, the result is just optimised for a particular engine speed. But as you can see different class of vehicle have different needs so when their engines are running other than the compromising revolution, results in less power and decreased efficiency.

So With VVT, power and torque can be optimised across a wider rpm band without any drawbacks. The most noticeable results are:

• High power figure at higher RPM
• Increase in torque figure at Lower RPM

VVT not only varies the timing of opening and closing of valves but also changes the valve lift. At high speed, higher lift quickens air intake and exhaust, thus further optimise the breathing. Have a look at this video

VVT’s benefits 

• Internal exhaust gas recirculation.By allowing for more direction for internal gases, the variable valve timing system can cut down on emissions, which is critical for auto makers working to get their cars and trucks in compliance with federal or state emissions controls
• Increased torque.Variable valve timing systems can provide better torque for an engine
• Better fuel economy. with more precise handling of engine valves, some auto makers have shown that VVT can produce better fuel economy for vehicles

How Is Variable Valve Timing Accomplished?

Up till now I have discussed about how a VVT system affect the performance and its importance but now I’m gonna tell you how this theoretical model is mechanically achieved in an engine.

The mechanical (or in some case electro-mechanical) setup of VVT system differ from one manufacturer to other but the whole system works on same principle as explained above. Like Honda introduced the VVT technology as VTEC (Valve Timing Electronic Control). First appeared in Civic, CRX and NSX, then became standard in most production models. You can see the VTEC mechanism as 2 sets of cams having different shapes to enable different timing and lift (exactly same as shown in video above). One set operates during normal speed, say, below 4,500 rpm. Another substitutes at higher speed.
On the other hand let’s take BMW for eample, they have introduced this system as VANO (Variable Nockenwellensteuerung). You can easily understand the working of VANO system from this pic. As you can see the end of intake camshaft incorporates a gear thread. The thread is coupled by a cap which can move towards and away from the camshaft. Because the gear thread is not in parallel to the axis of camshaft, phase angle will shift forward if the cap is pushed towards the camshaft. Similarly, pulling the cap away from the camshaft results in shifting the phase angle backward.

Still finding it difficult to understand? I’ve searched out a video for you, take a look

I think by now you got my point of ‘same principle but different working’.

Different Variable Valve Timing Implementations

Here is a quick list with the most well known variable valve timing implementations. As you can see, manufacturers use their own names for the same thing.

Toyota
– VVT (Variable Valve Timing)
This was the first implementation of Toyota that was using variable timing of the intake cams.
– VVT-i (Variable Valve Timing with Intelligence)
The follow-up design of Toyota was using hydraulic (oil based) system to change the timing through camshaft gear and timing belt (mechanically) and thus achieve different overlap timing. The aim of this design was efficiency.
– Dual VVT-i (Dual Variable Valve Timing with Intelligence)
This one uses the VVT-i technology but instead of applying it just to intake valves, it also operates on the exhaust ones.
– Triple VVT-iE (Variable Valve Timing with Intelligence by Electric Motor)
Similar to the Dual VVT-i with the difference that this design uses an electric motor to change the intake camshaft’s timing. Nevertheless, the exhaust timing is still hydaulic based.
– VVTL-i (Variable Valve Timing and Lift Intelligent System)
I have discussed this earlier in this post. It changes the camshaft’s lifting ability using an electronically controlled sliding pin.
– Valvematic
The newest technology of Toyota, Valvematic uses the previous VVTL-i technology along with new electronic timing adjustment functionality.

Subaru
– AVCS (Active Valve Control System)
This is used in turbocharged engines to improve air flow. To achieve this the system uses hydraulic (oil based) support that changes the intake camshaft’s rotation. The whole implementation is controlled via vehicle’s Engine Control Unit (ECU).
– Dual AVCS (Dual Active Valve Control System)
As in the Toyota case, this does not only adjust the intake valves timing but also the exhaust ones.
– i-AVLS (Intelligent Active Valve Lift System)
A newer technology that is similar to Honda VTEC. It has two different intake lift profiles that are changed after a predefined RPM limit to increase camshaft’s lift. The whole operation is electronic using vehicle’s ECU which triggers solenoids that change the oil pressure. In addition to the variable lift system, this implementation also uses hydaulic pressure to change camshaft’s timing.

Honda
– VTEC (Variable Valve Timing and Lift Electronic Control)
I already gave a quick overview of this technology. It electronically selects between two different camshaft profiles based on the engine’s RPMs. This can change the lift, duration and valve timing.
– VTEC-E (Variable Valve Timing and Lift Electronic Control for Efficiency)
As its name implies, this is an improvement of the original VTEC to provide efficiency in the whole RPM range. This was done using an hydraulic controlled sliding pin to change the valve lift.
– 3-Stage VTEC (3-Stage Variable Valve Timing and Lift Electronic Control)
All of the previous implementations had just two camshaft profiles which were operating in low and high RPMs respectively. This one included a third one to achieve more performance in middle RPMs.
– i-VTEC (Intelligent Variable Valve Timing and Lift Electronic Control)
Apart from the 2-stage VTEC, this implementation also supports an additional lifting of the intake valves using sliding pins which are also ECU, electronically controlled.
– i-VTEC with VCM (Intelligent Variable Valve Timing and Lift Electronic Control with Variable Cylinder Management)
Similar to the previous one with the addition of VCM. The latter technology will keep some cylinders deactivated by simply keeping all of their intake and exhaust valves closed if the required power is produced without them. This was an additional fuel consumption management system.
– i-VTEC i (Variable Valve Timing and Lift Electronic Control for Injection)
Simiar to i-VTEC but designed especially for direct fuel injection engines.
– AVTEC (Advanced VTEC)
The newest Honda VVT technology which despite VTEC’s initial operation, it provides continuous variable valve timing throughout the whole RPM range using various sensors that are connected to the vehicle’s ECU.
– HYPER VTEC (Hyper Variable Valve Timing and Lift Electronic Control)
This was the first ever VVT implementation for motorcycles, it features an additional intake valve that remains closed until an RPM limit is reached.

Nissan
– N-VCT (Nissan Variable Cam Timing)
Using an ECU controlled solenoid, it alters the camshaft’s rotation and consequently, the valve timing.
– VVL (Variable Valve Lift and Timing)
Using an hydraulic, oil based system which is ECU controlled it selects between different camshaft profiles, identical to the initial VTEC design.
– CVTC (Continuous Variable Valve Timing Control)
Using hydraulic power it adjusts the camshaft’s gear and timing belt to perform the valve timing.
– VVEL (Variable Valve Event and Lift)
This is one of the most advanced we have discussed so far. The ECU uses some stepper motors to adjust the valve timing and lift throughout the operation of the engine and not after a specified threshold.

Yamaha
– VCT (Variable Cam Timing)
This was a quite innovative approach of moving the camshaft in order to have variable lift and timing.

BMW
– Valvetronic
This is a complex design where the vehicles are equipped with electronic accelerator pedal that depending on the requested load, the ECU will lift the appropriate intake and exhaust valves accordingly.
– VANOS (Variable Nockenwellensteuerung)
Most cars equipped with Valvetronic also have VANOS. This uses an advanced method of moving the camshafts so that the valve timing is adjusted based on the driving style. However, its operation is limit based (it is activated at certain RPM levels) and it affects the intake camshaft(s) only.
– Double VANOS (DoubleVariable Nockenwellensteuerung)
This one overcame the issues of the previous design meaning that it supports continuous operation in both intake and exhaust valves.

Mitsubishi
– MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)
The only VVT implementation by Mitsubishi combines various features mainly for turbocharged vehicles. Its operation in also based on cams’ profiles but they are not strictly limited to a predefined RPM limit. Depending on numerous measurements that ECU collects it might start working on different RPMs. Finally, it works on both intake and exhaust valves.

Mazda
– S-VT (Sequential Valve Timing)
Once again, this model uses hydraulic pressure which is ECU controlled to rotate the intake camshaft.

Volkswagen Group
– VVT (Variable Valve Timing)
Recently, VW included this new feature to its models. The operation is based on a hydraulic system on the timing belt that performs VVT on the intake valves.

Porsche
– VarioCam
This was a very innovative approach during the time of its development. It implements VVT by adjusting the tension of the timing belt or chain that connects the two intake and exhaust camshafts.
– VarioCam Plus
An improvement of the previous technology, this one includes electro-hydraulic lifters that can perform two-stage lifting which leads to performance similar to Honda VTEC.

Suzuki
– VVT (Variable Valve Timing)
It uses an hydraulic system that changes the camshaft’s rotation and it is ECU controlled.

Alfa Romeo
– TwinCam
Although this does not directly implements VVT, it is a slight VVT technology. Mostly, an improvement of classic DOHC. It operates using a double row timing belt that alters the valve timing between the two camshafts.

So this is it. This is how I started off with my first technical blog post here at AutoSpace. So, was that article helpful? Do let me know. If you have any suggestion or opinion use our comment box to share with us also if you think that I missed something important, feel free to kick me.

Story Reference: (AUTOZINE and xorl.wordpress.com)

The post Tech Talk: Variable Valve Timing (VVT) appeared first on AutoSpace.

That’s why I’ve decided to answer these questions, and explain in simple terms just what is the difference between all these ratings, and which power rating gives you a better understanding of engine power. So lets begin.

Back in the old days when horses were pretty popular, there a marvelous piece of engineering that was replacing “real” horses very rapidly, ‘ The Steam Engines‘. At this time, people started to make comparison between horses and engines and that very moment was the creator of the question of the century(Ah.. don’t take it personally), “Which one is better, a horse or a steam engine?”. You may think, ‘oh..simple, its Steam Engine’ but back then it was yet to be proved. So what could be the solution? You’ll know in a minute.

The pioneer, James Watt,(who’s also inventor of steam engine) came forward with a revolutionary idea of labeling power of an engine in term of  horses, so that everyone could understood which is better ‘an animal or the machine’.  Watt observed that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute). The wheel was 12 feet in radius; therefore, the horse travelled 2.4 × 2π × 12 feet in one minute. Watt judged that the horse could pull with a force of 180 pounds. So by simple physics:

However, he noticed that different horses produced different power as the power varied from horses to horses due to difference in age,size and breed. After a long observation he finally settled at the 33,000 ft·lbf/min figure which if we convert into SI unit gives 745.699 W. So

Also, if you know the formula which looks exactly like this:-

you can easily figure out the problem in measuring the power,  practically. Give it a go.

Got it? Let me explain. Since torque is radius times force and since here that force is load/weight which is tied at the end of crankshaft by a rope (well.. not really, just imagine so for the sake of explanation). As power is dependent on torque, which is in turn dependent on weight, which is still hanging on a rope,  and since engine works at very high rpm, it wouldn’t be a good idea to hang a weight at the end of speedy crankshaft.

Now it was time for the engineers to find a solution for measuring the power more practically. Here they came up with a very ingenious solution. What they did was simply replace the load with some kind of ‘resistance’ (no…not the electrical one). A ‘resistance‘ here is something that opposes the motion of speedy crank, also what could work than a brake for this job.

So the amount of heat generated by applying the brakes which are bolted on drive shaft,  per unit time, gives the power rating of that engine. And the unit of power obtained by this method is known as BHP or Brake Horse Power.

The difference between HP and BHP didn’t even exist until recently. In order to get bigger numbers, engine manufacturers (including car makers), placed a single unit on a testing rig, and connected the drive shaft to the brake. It measured the pure horse power coming from the engine, without any auxiliary units. But seeing as how that wasn’t accurate with what customers were experiencing, a new SAE certification process appeared. The engine was now measured with all of its auxiliary systems, like transmission, fuel pumps, etc, while an independent observer was present. As you can imagine, a reduction in power ratings was experienced, as many systems take a toll on the eventual output of the engine. BHP is still used regularly in Great Britain (where it is mistakenly explained as British Horse Power, sometimes).

I hope you’re with me so far. If Not, please use our comment box and feel free to share your opinions with us. Let’s move on!

Car maker often prefer to use this measurement as it is bigger in terms of figures. Let’s say a car generates 100HP then that same car generates approx 102PS and you know, Bigger is Better.

Last but not least, WHP comes from ‘wheel horse power’, but you can also find it written as RWHP (rear-wheel horse power). Its the amount of power wheels actually send to the road. You get WHP figure by running the car on a rolling road (aka dyno).  Of course the tyres make a difference, and the type of dyno, but the rating is usually pretty close to the SAE-verified HP rating.

So now, the next time a car maker flaunts various ratings in your face, you’ll know just how powerful the engine really is

The post Did You Know: What’s the difference between kW, HP, BHP, PS or WHP? appeared first on AutoSpace.

As with all forms of motorsport, the trick is to get as much weight as low to the ground as possible. For the driver, that means a seating position that’s not just cramped, but a mere 10 centimeters off the ground. Directly behind him is a Kevlar-lined fuel tank fitted with a series of baffles to keep high-test gas from sloshing around as the car brakes, accelerates and turns at g-forces normally reserved for fighter pilots.

It’s an impressive example of what it takes to create some of the fastest vehicles on the planet.

The endeavor could not have been as easy as taking a chainsaw or even a Goldfinger-style laser and cutting it in two. In fact, the task took the team two years to complete, and all you have to do is scroll down and watch the video to see the results.

Video:

The post What’s Inside a F1 Car? appeared first on AutoSpace.

Unlike the Segway that’s mainly used for outdoors, the much smaller UNI-CUB is a one-person scooter for indoor spaces. Honda first announced the personal transpo system back in 2009 as U3-X, and the UNI-CUB that you can see in the video below  is the latest update to its design.

The lithium-ion battery-powered machine has a compact design with a seat fashioned like a saddle. Honda claims it’s easy enough to balance, but we bet the injured, the sickly, and the elderly who have the most use for something like this would have a hard time getting used to riding it.

Improvements over the U3-X include a saddle-style seating position that puts the rider at eye level with other pedestrians. Honda claims this “promotes harmony between the rider and others, letting the rider travel freely and comfortably inside facilities and among moving people.”

The UNI-CUB can move in any direction you choose, no matter where you’re facing. To control it, you only need to shift your weight toward one direction or use its smartphone app. While it’s not yet ready for release, Honda will be testing the UNI-CUB in June at Japan’s National Museum of Emerging Science and Innovation.

Despite those advances, the UNI-CUB has some of the same limitations as its predecessor: It can only travel at about 3.5 mph and its battery only lasts about an hour. Most importantly, it doesn’t have a backrest or the required stability to replace a wheelchair or other medically required mobility aid, so it’s essentially a very convoluted way for able-bodied people to get around no faster than they could walk.

Video:

The post Honda’s Uni-Cub – Personal Mobility Redefined appeared first on AutoSpace.