A better mousetrap – i.e. Valvetrain control, from the minds at Hyundai. Wayne Gerdes – CleanMPG – July 3, 2019 Hyundai will soon be releasing an all-new and unique valvetrain control technology that is designed to meet a wider variety of driving conditions. Hyundai calls it Continuously Variable Valve Duration (CVVD). The innovation was revealed within the brands Smartstream G1.6 T-GDi, the first engine to feature the technology and slated to be inside the all-new 2020 Sonata (ECO trim possibly?) this fall. CVVD optimizes both engine performance and fuel efficiency. The valve control technology regulates the duration of valve opening and closing according to driving conditions, achieving a 4% boost in performance and a 5% improvement in fuel efficiency while also reducing overall SMOG forming emissions by 12%. Continuously Variable Valve Duration An internal combustion engine’s performance and efficiency have been governed by variable valve control technology that adjusts the timing of valve opening and closing and depth of the valve’s opening, with engine power produced through the fuel intake-compression-expansion-exhaustion cycle. Typical variable valve control technologies manage the timing of the valve’s opening and closing (as in Continuously Variable Valve Timing - CVVT) or control the volume of air admitted by adjusting the depth of the opening (Continuously Variable Valve Lift - CVVL). Previous variable valve control technologies could not regulate valve duration, as the valve’s closing timing was subordinate to opening timing and could not respond to diverse driving situations. CVVD takes the technology in a new direction by adjusting how long a valve is open. When the vehicle is maintaining a constant speed and requires low engine output, CVVD leaves intake valve open until the middle and closes the valve near the end of the compression stroke. Aka, a fully atkinsonized low torque intake topology. This helps to improve fuel efficiency by reducing the resistance caused by compression, aka pumping losses. When high engine output is demanded, such as when the car is driving at a high speed, the intake valve is closed at the beginning of the compression stroke to maximize the amount of air used for the explosion, enhancing torque to improve acceleration. Smartstream G1.6 T-GDi Engine Unveiled alongside the new CVVD technology is the new Smartstream G1.6 T-GDi Engine, a I4 gasoline turbo unit with 180 hp and 195 lb-ft of torque. The new powertrain is the first to utilize the Group’s new CVVD technology and also features Low-Pressure Exhaust Gas Recirculation (LP EGR) to improve fuel efficiency further. The exhaust gas recirculation system returns some of the gas burnt by the engine to the combustion chamber, producing a cooling effect and reducing the emission of nitrogen oxides. The G1.6 T-GDi also features a low-pressure system that redirects the burnt emission gas to the front of the turbocharger compressor, rather than the intake system, to increase efficiency under the high load condition. Additionally, the new unit has an Integrated Thermal Management System that quickly heats or cools the engine to an optimal temperature, and a strong direct spray system that achieves 5,076 psi, surpassing the 3,626 psi of the current T-GDi engine. The newly design engine engines friction has reduced by 34% with the application of low friction moving parts. The new Smartstream G1.6 T-GDi engine will be available in the 2020 Hyundai Sonata 1.6L Turbo set for introduction in the second-half of this year. 2020 Hyundai Sonata with the Smartstream G1.6 T-GDi cutaway 2020 Hyundai Sonata Eco - Early Conclusions The current Sonata Eco with the 1.6L GDI-T mated to the 7-speed DCT achieves a 28/37 mpgUS city/highway rating. Might we see a 29/39 mpgUS city/highway rating in a 2020 Sonata Eco model with it, the Smartstream G1.6 T-GDi, inside? This result would edge out the already fantastic 40 + percent thermodynamically efficient 2.5L I4 in the Camry LE/XLE (28/39 mpgUS city/highway) but will probably still fall behind the super-efficient base 2019 Camry with its segment leading and sky high 29/41 mpgUS city/highway rating. Easily achieved which I might add. Oh how I would have loved to have been working on this Valvetrain project at Hyundai and I cannot wait to drive one.
It would be interesting to see a side-by-side efficiency comparison with Wayne Gerdes at the wheel. Was the efficiency worth the added complexity? (it seems car makers are seeing what they can achieve with powerful CPUs now available to micromanage all aspects of the engine...) I guess the true benefit will be that the lead-footed ones will get the driving feel they want, while the rest will have a more fuel efficient car. BTW, I love those cutaway renditions. Always have...
For those that drive efficiently, this is of little benefit, but they are the minority of drivers. I'm wondering how this compares to the others' wide range valve control. I think Toyota's latest can go from full Otto to full Atkinson.
I'm too slow and stupid to grok how the system actually works from that video. I found another animation that illustrates operation better (at least for me). It puts operation in context with VVT, CVVT, and CVVL You may have to mute the audio:
Would this work better?: The newly designed engine reduces friction by 34% with the application of low friction moving parts.
Hi All: Hyundai just launched its latest 2020 Sonata Hybrid equipped with world’s first Active Shift Control (ASC) technology and solar roof system in the Korean market. 2020 Hyundai Saonta Hybrid w/ Solar Roof Option The hybrid model is equipped with unique cascading grille, rear spoiler, and alloy wheel which with improves aerodynamics. Hyundai’s solar roof system makes its debut on the 2020 Sonata Hybrid. The system recharges the battery to increase travel distance while preventing unnecessary battery discharge. The solar roof system, with 6 hours of daily charging, is expected to increase travel distance by an extra 800 miles annually. A dubious claim at best but … Think of a fully charged hybrid pack offering about 1.5-mile before first engine start. 5 times a week provides 7.5 miles per week or 390 miles per year with a full 6-hours of sun. Maybe the Sonata Hybrid includes a slightly larger pack of maybe 2.0 or more usable kWh? We will see. Hyundai also applied world first ASC transmission technology to improve fuel economy and durability of the transmission by minimizing friction between shifts. The 2020 Sonata Hybrid is equipped with the all-new Smartstream G2.0 GDi HEV engine and 6-speed hybrid transmission. The heavily atkinsonized engine’s power output is 148 hp with maximum torque of 139 lb-ft. The vehicle’s electric motor delivers power output of 38 kW. Combined system power output is 192 hp with a combined fuel economy of 47 mpgUS. This result is not homologated on our EPA however so expect maybe a 42 mpg combined final. This equivalent to the current 2019 model. The new Sonata supports a ‘Digital Key’ that can control selected vehicle systems remotely via smartphone. Using Bluetooth Low Energy (BLE) communication, users can lock and unlock the vehicle, activate the alarm and start the engine. The Sonata Hybrid also has onboard array of advanced safety features including Forward Collision-Avoidance Assist and Lane Follow Assist. Forward Collision-Avoidance Assist is capable of pedestrian detection. Using front radar and front view camera sensors, FCA operates in three stages. Initially warning the driver visually and acoustically, it assesses the nature of the collision danger and can apply increasing amounts of braking force to avoid a collision or minimize damage when a collision is unavoidable. The system is activated when a vehicle, pedestrian or cyclist is sensed in front of the car. Lane Follow Assist automatically adjusts steering to help keep the vehicle centered in its lane of travel. LFA can keep the vehicle centered at speeds between 0 and 90 mph. 2020 Hyundai Sonata Hybrid Tech Specs Length: 192.9 in Width: 73.2 in Height: 56.9 in Wheel Base: 111.8 in Cargo Volume (Trunk): 17.7 cu. ft. Wayne
Jason, of Engineering Explained, released a utube video covering Hyundai's CVVD technology today. This is the best demonstration of this not-easy-to-understand system that I have seen to date.
Yes, Jason is sharp, enthusiastic & delineates well, for my limited knowledge. Funny, I just saw Jason on YouTube & now I see the video here. Good ideas explained well get around quickly? P.S. Someone contrasted the ideas of Toyota with Hyundai's development. It seems that both technologies do NOT negate each other, but could be incorporated into each other. Someone else was complaining about the "complexity" of the Hyundai system. Will CVVD be overwhelmingly more complex than "new" tech that occurred when four valves per cylinder became the standard over two valves, or turbos, supercharging or staged turbos, of the past. The real problem with complex tech are the use of such tech by manufacturers who often don't have the quality of original manufacturers. P.S. II.... With all this tech, I suppose a manual transmission won't ever be used. But, with more torque at low rpms being one of the excellent features of the CVVD, it seems that a manual tranny would work very well with the CVVD.
