What is VVT-i engine?

For car users must have felt the alerts Toyota engine reliability tech-Variable Valve Tuning-Intelligent (VVT-i). Yes, now replace the VVT-iToyota, that has begun to be appliedin 1991 at the Toyota 4A-GE engine 5cylinders.

Machine which was first introducedin 1996 has been used in most carsof Toyota. In addition the machine is claimed to make the engine moreefficient and powerful,environmentally friendly and fuel efficient. Then how the systemworks so as to establish a satisfactory result.

As described Wikipedia, the workings of this technology are quite simple. To calculate the time of opening and closing valve (valve timing) is optimal, the ECU (Electronic Control Unit) to adjust the engine speed, intake air volume, throttles position (accelerator) and the water temperature. In order for the target valve timing is always reached, camshaft or crankshaft position sensor gives a signal in response correction.

Easily VVT-i system will continue to correct the valve timing or line out of fuel and air.Adjusted by stepping on the accelerator and expenses incurred in order to produce optimumtorque at each wheel and engine load. With so will result in optimal power, fuel-efficient and environmentally friendly.

Toyota recorded a few variants are adopting technologies VVT-i like Toyota Avanza, ToyotaInnova, Toyota Yaris and Toyota Vios.

TOYOTA VVTi ENGINE

VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota, similar to the i-VTEC technology by Honda. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. Perodua use this technology and convert the name toDVVT(Dynamic Variable Valve Timing). The VVT system is a 2-stage hydraulically controlled cam phasing system.

VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position.

Engine designers have known for a long time that they could get better performance out of an engine under certain circumstances by allowing the intake valve to open slightly before the exhaust valve closes. This increases the time for the fuel/air mixture to enter the cylinder during the intake stroke. In this condition the exhaust and intake valves are open at the same time; this is called ‘valve overlap’. In conventional engines ‘valve overlap’ timing is fixed.

Fixed valve overlap allows the engine to perform well within a certain rev range, however there are three main undesirable side effects.

1) Fuel is wasted – the fuel/air mixture is not always efficiently burned and this causes unburnt fuel to pass through the engine.

2) Higher levels of undesirable exhaust emissions are produced.

3) Power output potential is not fully realised.

Variable valve timing allows the relationship between the separate inlet and exhaust camshafts to vary the valve timing overlap. In doing so it overcomes the side effects described above by using a computer to continuously vary the intake valve timing and overlap. The valve timing and overlap are adjusted through a series of simple mechanisms to ensure the optimum conditions apply across all the working rev range. The advantages are lower fuel consumption, lower exhaust emissions and higher power output. Because the system is continuously variable, an ‘i’ for ‘intelligent’ has been added to the acronym.

In 1998, “Dual” VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza’s 3S-GE engine. Dual VVT-i is also found in Toyota’s new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Dual VVT-i is also used in the Toyota Corolla (1.6 dual VVT-i 124bhp).

Other Dual VVT-i engines include the 1.8L 2ZR-FE I4, used in Toyota’s next generation of compact vehicles such as the Scion XD. It is also used in the 2JZ-GE and 2JZ-GTE engines used in the Lexus IS300 and in the Toyota Supra. By adjusting the valve timing engine start and stop occurs virtually unnoticeably at minimum compression. In addition fast heating of the catalytic converter to its light-off temperature is possible thereby reducing hydrocarbon emissions considerably.

Toyota GT86 Engine

World's first horizontally opposed engine with D-4S.


The GT 86's engine is the result of a joint Toyota and Subaru development 
programme that brings together their technical know-how and mutual passion for sports cars.

Toyota has added its D-4S injection technology to Subaru's new, horizontally opposed, naturally aspirated 1,998cc four-cylinder boxer engine. This system features separate twin injectors for both direct and port injection, and a high 12.5:1 compression ratio, increasing power and torque across a wide range of engine speeds without sacrificing fuel efficiency and environmental performance.

The flat-four engine has equal bore and stroke of 86.0mm and drives through either a six-speed manual or six-speed automatic transmission. The manual offers quick, precise shifts using a tactile, short-throw lever; the automatic transmission can be controlled using paddle shifts mounted on the steering wheel.

Power is distributed to the rear wheels via a limited slip differential to give the best possible grip in all driving conditions. The ABS and switchable vehicle stability control systems have been tuned specifically to deliver dynamic stability at the limit of the car's performance envelope with minimal electronic intervention to help preserve the purity of the driving experience.

FLAT-FOUR ENGINE.


A flat-four or horizontally opposed-4 is a type of four-cylinder engine, a flat engine with four cylinders arranged horizontally in two banks of two cylinders on each side of a central crankcase. The configuration results in inherently good balance of the reciprocating parts, a low centre of gravity, and a very short engine length. The layout also lends itself to efficient air cooling. This is no longer a common configuration, but some brands of automobile use such engines and it is a common configuration for smaller aircraft enginessuch as made by Lycoming, Continental and Rotax. Although they are somewhat superior to straight-4s in terms of vibrations, they have largely fallen out of favor because they have two cylinder banks thus requiring twice as many camshafts as a straight-4 (if an OHC rather than OHV or F-head configuration is used) while the crankshaft is as complex to manufacture. The low centre of gravity of the engine is an advantage. The shape of the engine suits it better for mid engine or rear engine designs. With a rear engine layout it allows a low-tail body while in front engine designs the width of the engine interferes with the ability of the front wheels to steer. The latter problem has not stopped Subaru from using it in its all-wheel drive cars, where the difficulty of fitting the short engine between the front wheels ahead of the front axle is compensated for by the ease of locating the transmission and four-wheel drive mechanisms behind it, between the front and rear axles.

The bore and stroke, the basic structure of this engine, have been reviewed to achieve a compact combustion chamber as well as a long stroke, which was difficult previously due to chassis mounting conditions in boxer gasoline engines. This allows high combustion efficiency, and generates a sufficient mid-low speed torque with improved fuel efficiency and practicality. Improved fuel efficiency has been achieved through optimization of intake port configuration and the addition of partitions inside ports, the use of TGV (Tumble Generated Valve), and the use of an EGR (Exhaust Gas Recirculation) cooler. AVCS (Active Valve Control System) is used on both intake and exhaust valves. For the intake side in particular, an intermediate lock system allows valve timing to be advanced or delayed for precise control over intake and exhaust valve timing, allowing maximum engine performance in output, fuel efficiency, and exhaust emission. The use of lightweight primary moving parts, such as pistons and connecting rods, and a highly efficient and compact oil pump provides an approximately 30% reduction in friction loss and improves fuel efficiency and revolution response. Cooling has been optimized by using separate engine cooling circuitry for the block and the head, resulting in improvements in fuel efficiency and output characteristics. 



ADVANTAGES OF HORIZONTALLY OPPOSED ENGINE.

1. Compared to in-line engine and V-type engine, the height of horizontally opposed engine is lowered, allowing a lower center of gravity for the entire vehicle. 
2. The lightweight, compact design and symmetrical layout allow a smaller yaw moment of inertia. 
3. The pistons on the left and right sides move in symmetrical opposition, cancelling out any vibration. This allows a smooth revolution feeling with little vibration. In addition, since no balancer shaft is required, the weight increase of the engine is minimized.
4. Since the engine is sitting low, strong forces from the front such as a head-on collision will result in the engine being driven underneath the car. As a result, there is a reduced risk of the engine being forced into the cabin and injuring passengers. 
5. Since the engine is sitting low, there is ample space between the engine and the hood. This space will absorb some of the force in the event of a collision, reducing injury to pedestrian.

• http://www.tune86.com/toyota-gt-86-technical-specs-info-details
• http://en.wikipedia.org/wiki/Toyota_86
• http://www.youtube.com/watch?v=e_1UP29lGt0
• http://www.youtube.com/watch?v=1G2AggjJCy8
• http://en.wikipedia.org/wiki/Flat-four_engine
• http://www.zercustoms.com/news/2010-Subaru-Boxer-Engine.html

BMW ( VALVETRONIC)

2014 BMW I8.

ENGINE MODEL i8

Behind the bodywork and aluminum frame is both a BMW Twin Power in-line three-cylinder combustion engine that powers the rear wheels and a hybrid synchronous motor that powers the front wheels. The all-wheel drive hybrid claims a top speed of 155mph (expect a later unrestricted M variant). Even more impressive is the 94mpg and CO2 rating of 59 g/km. The gasoline four-valve in-line three-cylinder alone generates 231hp and 236 lb-ft of torque to the rear wheels through a six-speed automatic transmission. The BMW eDrive hybrid synchronous motor produces 131hp and 184 lb-ft of torque to the front wheels through a two-stage automatic transmission. Together the total output equates to 362hp and 420 lb-ft of torque. For those interested in charge time, it will take 3.5 hours for a full charge if connected to a 110v power outlet but if you spring for the BMW i Charging Station the process takes only 1.5 hours. Along with torque distribution designed to optimize efficiency is a five-mode Driving Experience Control switch. Comfort mode balances performance and fuel efficiency with unrestricted access to all features. Eco Pro mode promotes optimal mpg and lowers the electrical draw of features like AC, seat heating and heated mirrors. According to BMW, in an everyday driving scenario on a full charge and tank of gas the i8 can travel over 310 miles in Comfort mode. The lithium-ion battery pack (liquid-cooled), combustion engine, electric motor, power electronics, chassis components, and structural components all fall within the Drive module. Helping improve performance and stability, the i8 has a low center of gravity of under 18in - lower than any other current BMW model - combined with near 50:50 weight distribution.

DRIVE TRAIN.

1.  The BMW i8 embodies a revolutionary, future-focused interpretation of driving pleasure for which BMW is renowned. It was purpose-designed as a plug-in-hybrid sports car offering agile performance, near 50:50 weight distribution and outstanding efficiency. An exceptionally lightweight and aerodynamically optimised body – including a passenger cell made from CFRP – plus advanced BMW eDrive drive system technology, a compact, highly turbocharged 1.5-litre petrol engine with BMW TwinPower Turbo technology and intelligent energy management all come together to create an overall concept that represents a new landmark in the EfficientDynamics development strategy.
2. first BMW production model to be powered by a three-cylinder petrol engine. This highly turbocharged unit is equipped with latest-generation BMW TwinPower Turbo technology with high-precision injectors positioned between the valves, along with VALVETRONIC.  The low roll torque is further reduced by a balancer shaft, while a multi-stage damper integrated in the automatic transmission ensures very smooth and refined running at low rpm. This three-cylinder combustion engine in the BMW i8 develops 231hp and drives the rear wheels, while a maximum torque of 320Nm is available from 3,700rpm.
3. The car’s second power source is a 96 kW/131hp hybrid synchronous electric motor which sends its power to the front axle.  The motor develops 250Nm torque from a standstill.  As well as providing a power boost to assist the petrol engine during acceleration, the electric motor can also power the vehicle by itself with a range in everyday driving of up to 22 miles and a top speed of 75mph on electric power alone, drawing its energy from a lithium-ion battery.  Developed by BMW Group, the high-voltage battery has a liquid cooling system, offers a maximum usable capacity of five kilowatt hours and can be recharged from a conventional household power socket, at a BMW i Wallbox or at a public charging station.
4. The rear wheels of the BMW i8 are driven by the petrol engine via a six-speed automatic transmission, while the front wheels receive their power from the electric motor via a two-stage automatic transmission. Combined maximum output of 362hp and combined peak torque of 570Nm provide all-wheel-drive performance which is as dynamic as it is efficient.

ADVANTAGES OF i8 ENGINES.

• One of the basic advantage of the BMW i8 car is its extraordinary design combined with a similar fuel efficiency almost akin to that of a small car.
• Can use either petrol or electric engine or using both motor.
• On entering the corner, the power split is biased towards the rear wheels to improve turning precision. For more vigorous acceleration out of the corner, the powertrain controller returns to the default split as soon as the steering angle becomes smaller again.

VALVETRONIC

This highly advanced technology replaces the conventional throttle butterfly with a electrical mechanism that controls the amount of lift of the individual intake valves on each cylinder. Your engine is able to breathe freely, delivering better performance while using less fuel.

The performance of the engine is more efficient and immediate, thanks to the elimination of the pumping losses and air-flow disturbance caused by a conventional throttle butterfly. Instead, air can flow through the intake manifold freely, and Valvetronic precisely regulates the quantity of air entering the cylinders.

Valvetronic uses a stepper motor to control a secondary eccentric shaft fitted with a series of intermediate rocker arms, which in turn control the degree of valve lift. The throttle butterfly is no longer needed as a means of controlling the air supply - though for safety reasons it is still fitted as an emergency back-up.

By optimising the fuel/air mix process, Valvetronic produces fuel savings of up to 10 percent (based on the ECE driving cycle). In addition, Valvetronic improves cold start behaviour, lowers exhaust emissions and provides smoother, more immediate power.

      Additional Links, feel free to check them out!      ツ

• Valvetronic
• US auto parts (Valvetronic) 
• BMW forums (Valvetronic)
• http://www.europeancarweb.com/news/1309_bmw_i8_coupe_specs_announced/ 
• http://en.wikipedia.org/wiki/BMW_i8
• https://www.press.bmwgroup.com/pressclub/p/gb/pressDetail.html?title=the-new-bmw-i8-%E2%80%93-the-future-supercar-now&outputChannelId=8&id=T0145575EN_GB&left_menu_item=node__6728

BMW VANOS SYSTEM

VANOS

VANOS  is an automobile variable valve timing technology developed by BMW in close collaboration with Continental Teves. VANOS varies the timing of the valves by moving the position of the camshafts in relation to the drive gear. This movement varies from 6 degrees of advanced to 6 degrees of retarded camshaft timing. 

1. Single Vanos
2. Double Vanos
3. Vanos Performance

Single VANOS

VANOS is a combined hydraulic and mechanical camshaft control device managed by the car's DME engine management system. The VANOS system is based on a discrete adjustment mechanism that can modify the position of the intake camshaft versus the crankshaft. Double-VANOS adds continuous adjustability to the intake and exhaust camshafts.

VANOS operates on the intake camshaft in accordance with engine speed and accelerator pedal position. At the lower end of the engine-speed scale, the intake valves are opened later, which improves idling quality and smoothness. At moderate engine speeds, the intake valves open much earlier, which boosts torque and permits exhaust gas re-circulation inside the combustion chambers, reducing fuel consumption and exhaust emissions. Finally, at high engine speeds, intake valve opening is once again delayed, so that full power can be developed. VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy.

VANOS was first introduced in 1992 on the BMW M50 engine used in the 5 Series.

Double VANOS

The first double VANOS system appeared on the S50B32 engine in 1996. Later, BMW added "double" VANOS to its M52TU series of inline 6-cylinder engines, which changed the mechanism from fixed position operation to continuously variable, and added the same functionality to the exhaust camshaft, on a number of its cars. Double-VANOS (double-variable camshaft control) significantly improves torque and emissions since valve timing on both the intake and exhaust camshafts is adjusted to the power required from the engine as a function of gas pedal position and engine speed. On all BMW engines that use single VANOS, except S50B30, the timing of the intake cam is only changed at two distinct rpm points, while on the double-VANOS system, the timing of the intake and exhaust cams is continuously variable through a range of ~40 crankshaft degrees for the intake, and 25 degrees for the exhaust. The advantage of double-VANOS is that the system controls the flow of hot exhaust gases into the intake manifold individually for all operating conditions. This is referred to as "internal" exhaust gas re-circulation, allowing very fine dosage of the amount of exhaust gas recycled.

Double VANOS

VANOS Performance

Single and Double VANOS systems due to age and mileage often experience performance issues as well as complete failure of the BMW OEM Buna-N VANOS piston seals (which are often successfully repaired by the use of aftermarket Viton seals to replace the OEM Buna-N seals). Another common effect is a rattling sound coming from the upper valve train assembly. The original seal material was found to be inferior for the application and tends to break down within 75k - 100k miles. VANOS Seal & Rattle kits are available to address these shortcomings from aftermarket suppliers (but not from BMW -- BMW's solution when VANOS units fail is to remove the entire VANOS unit and replace it with a new one). VANOS repair may require special tools (cooling fan clutch wrenches, etc.) that can be rented or purchased from a variety of vendors.

For more more information on operation and reference, feel free to check the link below~ :)

• List of VANOS engines
• BMW first introduce VANOS in 1992 on the BMW M50 engine

BMW TWIN POWER TURBO ENGINES

The multiple award-winning petrol and diesel engines with BMW Twin Power Turbo technology are among the innovations from BMW Efficient Dynamics. They combine the latest fuel injection systems, fully-variable performance control and innovative turbocharger technology.

BMW Twin Power Turbo petrol engines.

How does it work. 

The technology concept of the BMW TwinPower Turbo petrol engines is applied throughout the series. Innovative turbocharger technology and Double-Vanos increase performance and ensure spontaneous response even at low speeds. The petrol injection system High Precision Injection and the fully-variable valve control Valvetronic lower consumption

Three components ensure that the BMW TwinPower Turbo petrol engines are capable of achieving the unique relationship between performance and consumption.

The innovative valve control Valvetronic (= variable valve and electronic) with Double-Vanos varies the hub of the inlet valve fully. This allows the engine to develop optimum power with less consumption. The Valvetronic also improves the mixture preparation and lowers fuel consumption by up to 10% (BMW internally-determined value based on ECE driving cycle). An additional effect is improved response.

Double-Vanos refers to the double variable camshaft control. This system controls the engine performance all across the speed range and enables lower consumption and fewer emissions at any speed.

High Precision Injection with its particularly accurate fuel dosage ensures extraordinarily efficient and clean combustion. This derives the maximum amount of energy from every drop of fuel.

Innovative turbocharging technology increases the engine’s power and puts it on par with much larger engines – and all this with fewer components, reduced inner friction and low weight. And thus with lower consumption and emissions.

Together with the other innovations by BMW Efficient Dynamics this allowed a fuel saving of up to 15%, for example, in the BMW 328i Sedan in relation to its predecessor the BMW 325i.

Saturn Engine (Basic Operation)

Saturn Engine(basic operation)

Saturn Engines are internal combustion engines. Internal combustion engines work by utilizing combustion to power the major parts of the engine. When the ignition is turned on, the electric starter motor sends power to the vehicle's spark plugs; the spark plugs are directly connected to the engine's cylinder block, and the ignition spark starts the combustion process by igniting the fuel stored in the combustion chamber.

The combination of fuel and air in the chamber is what moves the cylinders up and down. Many modern Saturn vehicles utilize direct-injection technology to aid with start up. This technology adds fuel directly to the combustion chamber instead of through anintake.

The engine's cylinders are connected to the crankshaft. When the cylinders are powered, the crankshaft rotates and generatespower to the vehicle.When you depress the accelerator pedal in the vehicle, you are opening the throttle plate. This pushes morefuel and air into the chamber, generating more power and higher engine RPM. 

Most Saturn vehicles use VVT (variable valve timing) technology to improve general engine operations. VVT allows the timing valves and cam of an engine to customize air flow and timing patterns. This allows for more power and efficiency at higher engine RPM.


2009 Saturn Astra

 1.8L DOHC engine

The Astra’s standard 1.8L DOHC engine is a sophisticated, powerful and economical power plant. It uses variable valve timing to optimize power and economy, delivering 138 horsepower (103 kW) and 125 lb.-ft. of torque (170 Nm).

The 1.8L engine includes two continuously variable camshafts, a highly efficient oil/water heat exchanger and a MAP-controlled thermostat. It also has a deep-drawn exhaust manifold that incorporates the catalytic converter and a two-step intake manifold that uses a rotary sleeve instead of conventional flaps to actuate the transition between low-rpm and high-rpm airflow. This design minimizes flow loss for optimal performance and efficiency.

The 1.8L engine also has a strong, lighter-weight cast iron cylinder block. It weighs only 59.5 pounds (27 kg), comparable to many aluminum-block engines. Oil-spray jets are incorporated in the block to ensure optimal piston cooling.

A five-speed manual transmission is standard in all models and helps the Astra deliver its great fuel economy. An Aisin electronically controlled four-speed automatic is available.

The four-speed automatic incorporates neutral idle, a feature that automatically shifts the transmission to neutral during stops and eliminates converter drag on the engine. It also is equipped with an automatic throttle kick-down feature, which actuates immediate downshifting during wide-open throttle driving for more immediate performance.

For 2009, customers in colder climates can order an oil pan heater for both XE and XR models.

• http://www.topspeed.com/cars/saturn/2009-saturn-astra-ar62089.html