Introduction variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. Infinitis vcturbo engine is the worlds first productionready variable compression ratio engine and it makes its production debut on the new qx50. The saab variable compression engine was a development project of saab automobile, for which it won an award both in 2000 and 2001. Variable compression ratio vcr is a system which is used to adjust the compression ratios of the internal combustion engine. Once established, this technology will likely become commonplace due to increasing. With a variable compression ratio diesel engine, the compression ratio used at part load can remain in the range of 1516. Opposedpiston engines with variable compression ratio. The compression ratio can vary from a highly boosted 8. An experimental investigation is carried out to study the effect of compression ratio on variable compression ratio engine using diesel oil. Compression ratios of 14, 15, 16 and 18 and engine loads of 3kg to 12 kg, in increments of 3kg, were utilized for diesel. Infiniti debuts breakthrough engine technology in new qx50. Variable compression ratio diesel engine performance analysis. Variable compression ratio is achieved by the new multi.
A variable compression ratio concept that can give a different expansion ratio to the compression ratio has been evaluated by means of a simulation of a turbocharged diesel engine. Higher loads require lower ratios to be more efficient and vice versa. The worlds first variable compression ratio engine is here, in a production car. The qx50 will be the industrys first use of a variable compression ratio system. The engine has a maximum thermal efficiency of around 40 percent, as much as twice the level of current gasoline engines in the industry, which average around 20 to 30 percent. Nissan has finally figured out the variable compression ratio engine, and it means you get more power from less fuel. Toyota variable compression engine patent shows ice not dead yet. Infinitis has developed the first variable compression ratio engine which will ever be used in a production vehicle. Devised by per gillbrand 20 years ago, the saab variable compression svc engine can vary its compression ratio between 8. Vcr engine in animationvideo or written format to following addresss.
What the heck is variable compression, how does it work, and. Full text of performance analysis of variable compression. For an siengine operating at stoichiometric mixture. Variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. Infiniti debuts breakthrough engine technology in new qx50 its the worlds first production variable compression ratio engine. Aug 25, 2014 introduction variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. Opposedpiston engines opes have been around since 1858 and serious variable compression ratio vcr devices have been available since the early 1950s. Harry ricardo built the first known variable compression ratio engine as a test engine in the 1920s to study knock in aircraft engines. The variable compression engine means that the compression ratio of the engine can be controlled at each engine operation condition. This would ensure good combustion stability and can assist in reductions in co and hc emissions in the lowload rangeespecially at low engine and ambient temperatures.
In this paper the performance characteristics are studied at various compression ratios and loads. The compression ratio is controlled by varying the ratio of the connecting rod length to the crank throw, hence the name variable crank radiusconnecting rod length. Infinitis dieselslaying variablecompression engine is. This unique variable compression technology represents a breakthrough in combustion engine design the qx50s 2. Aug 15, 2016 nissans infiniti division will present its first variable compression turbocharged vct engine at the paris motor show next month. The sophisticated engine control logic automatically applies the optimum ratio, depending on what the driving situation demands. Worlds first production variable compression turbo engine.
Varying the compression ratio during engine operation is one measure to optimize efficiency for the different fuels. Killed by saabs gm overlords due to budgetary reasons, the swedish automakers variable compression engine, or svc, had one of the most favorable riskreward ratios ive ever seen. The engine can produce any compression ratio from 8. Intake valve closing an overview sciencedirect topics. Sep 29, 2016 infinitis variable compression engine offers diesel efficiency with petrol power. Caterpillars variable compression ratio engine for hcci combustion. What the heck is variable compression, how does it work, and why does it matter. Lets say you are accelerating fast and the car is using quite a bit of power, it can use a compression ratio of 8. Variable compression ratio by myles bohon robert dorosko nana noel mae 442 dr. I dont know if this topic has arisen before but i had came across this concept several years ago and then was surprised to see that some manufactures had decided to pursue the concept. The first step is to define those terms and clarify the difference between them. A cylinder that has more gas high ve at a given engine speed will have a higher pressure at a given static compression ratio than it will when it has less gas lower ve. Vcturbo the worlds first productionready variable compression.
Infinitis variablecompression engine offers diesel. In operation, the vcturbo engine offers any compression ratio between 8. Science behind infinitis variablecompressionratio engine. The saab variable compression engine was a development project of saab automobile, for which it won an award both in 2000 and 2001 in a normal internal combustion engine, because cylinder bore diameter, piston stroke length and combustion chamber volume are almost always constant, the compression ratio cr for a given engine is almost always constant. Klang may 2006 outline traditional automobile engine compression ratio what it is how. The vcturbo changes its compression ratio seamlessly with an advanced multilink system, continuously raising or lowering the pistons reach to transform compression ratio, offering both power and efficiency, on demand. The arrival of the variable compression ratio engine will establish new. In order to find out optimum compression ratio, experiments were carried out on a single cylinder four stroke variable compression ratio diesel engine. A theoretical study of a variable compression ratio. The infiniti vct engine can change its compression ratio from a low of 8.
An animation of infinitis vcturbo engine in operation. What this means is the engine can produce significant horsepower by using the low. Heres exactly how infinitis variablecompression engine works. Aug 31, 2016 you know what variable valve timing is. The vct engine will allow for the compression ratio to be dynamically.
When high power output is demanded, the engine can be made to operate as a low compression ratio heavily boosted engine. When the more power of engine is needed during high load, the compression ratio is decreased, and when the higher efficiency is needed during low load, the compression ratio is increased. The worldsfirst variable compression ratio engine could. Nissans vcturbo engine is said to be the worlds first productionready variable compression ratio engine. Position of brown piston determines compression ratio of violet piston cylinder. Now infiniti has something new for you dive into, and its all about changing an engine s compression ratio. Now infiniti has something new for you dive into, and its all about changing an engines compression ratio. Increasing engine efficiency and power most of us are probably anxious to get rid of internal combustion engines ice and. When intake valve closing timing is changed, the effective engine compression ratio may vary although the effect is not exactly the same as changing the geometric compression ratio. A look at 10 hot new internal combustion engines design news. The advantage here is you can get the highest possible compression ratio based on the limits of the fuel at every engine speed. Variable compression ratio technology represents a breakthrough in. Jul 04, 2016 the saab variable compression engine was a development project of saab automobile, for which it won an award both in 2000 and 2001.
However, the axial layout lends itself to variable compression ratio with relative ease, and it is likely that a variable compression ratio duke engine is a real and potentially attractive. Recent developments in variable compression ratio engines. Low position makes volume of the combustion chamber small. Vcturbo first variable compression ratio engine explained. Tests were carried out at compression ratios of 16. Variable compression ratio how is variable compression. Nissans crafty engine ends a century of compromise wired nissans crafty. Nissan to unveil new variable compression engine daily. Variable compression engine how infiniti vct works. Saravanapprabhu, pg student, thermal engineering, department of mechanical engineering, sri ramakrishna engineering college, coimbatore641022, tamilnadu, india.
Variable compression connecting rods general discussion. Control module according to drivers accelerator pedal. But, in the highway, when not so much energy is being used to stay at constant speed, a ratio of 14. General motors new variable compression engine patent.
Smith, masanobu takekoshi abstract due to the ever increasing requirements for engine performance, variable compression ratio and displacement are drawing great interest, since these features. The electronic engine controller responds to the pressure on the gas pedal. The company claims its production ready, but its not slated to appear in any production car just yet. The concept of variable compression ratio promises improved engine performance, efficiency and reduced emissions.
Infiniti vcturbo engine worlds first variable compression ratio. The variablecompression ratio technology works as follows. When coupled with technologies such as turbocharging, variable valve actuation, and direct fuel injection, the effectiveness of the system is further increased. Infinitis variable compression engine is real, will debut.
In other words, for the small amount of new, unproved technology used, the potential benefits were phenomenal. Performance analysis of variable compression ratio engine. Variable compression ration technology represents a breakthrough in powertrain development. Theoretically, increasing the compression ratio of an engine can improve the thermal efficiency of the engine by producing more power output. Variable compression engines, as the name suggests, can alter their compression ratio, i. Variable compression engines allow the volume above the piston at top dead centre to be changed. Sep 30, 2016 dont get me wrong, the worlds first productionbound variable compression internal combustion engine is truly something. Right in the title of the patent, gm identifies that this is more than just a variable compression engine, by calling it the independent compression and expansion ratio engine. Variable compressionthe rest of the story motortrend.
In a normal internal combustion engine, because cylinder bore diameter, piston stroke length and combustion chamber volume are almost always constant, the compression ratio cr for a given engine is almost always. Infinitis dieselslaying variablecompression engine is here. The compression ratio for this engine would vary between 8. The technical specifications of the engine are given in table 3. The company is contemplating use of a compression ratio gauge on the instrument cluster to highlight how variable it is indeed, the full range of engine loads and speeds is mapped to assign the. This would give a complete idea how an engine behaves both at various loads and compression ratios. Application of variable compression ratio to a gasoline engine with continuously variable valvelift, speaker. The higher cylinder pressures and temperatures during the early part of combustion and small residual gas fraction owing to higher compression ratio give faster laminar flame speed.
Seminar on variable compression ratio engine learn. In general, a high compression ratio is better for. Experimental setup in the present study a 5hp variable compression ratio diesel engine is chosen with variable compression ratio from 14 to 20. Ppt variable compression ratio powerpoint presentation. The mce5 engine from mce5 development in lyon, france varies its compression ratio and uses a combined gear and rodcrank mechanism. Aug 31, 2017 toyota variable compression engine patent shows ice not dead yet. The advanced new vcturbo engine is the latest driverfocused. When red arrow points down, volume of the combustion chamber is min, the compression ratio is max and vice versa. Heres how it worksand how it achieves better power and. Aggressive engine downsizing with variable compression ratio and use of the extended atkinson cycle can provide large fuel economy gains that are exceptionally cost effective. Comparing engine maps each with respective optimum geometrical compression ratio for engines with fixed or fully variable valve lift respectively, fig. Sep 07, 20 for an ideal otto cycle the theoretical efficiency is given by, where r is the compression ratio and. Envera variable compression ratio engine technical report. A study of a variable compression ratio and displacement.
Adaptive steering in the qx50, a steerbywire system that is designed with driverassist tech in mind. A variable compression ratio duke engine the specific nature of a practical variable compression ratio mechanism for the duke engine has not been finalized. Benefits of the variable compression ratio engine with an hcci regime. Saab showed a prototype variable compression engine at the geneva motor show. As a consequence, the displacement of the engine changes and the compression ratio can vary anywhere between 8. The specific nature of a practical variable compression ratio mechanism for the duke engine has not been finalized. Saab variable compression engine generates 225bhp out of 1. This is done to increase fuel efficiency while under varying loads. Infinitis new vct changes the rules of small turbocharged engines variable compression ratio explained. Jul 04, 2016 saab variable compression engine generates 225bhp out of 1. Control unit hardware, software and calibration data set specifications camphaser vcr. Variable compression engines allow the volume above the.
Most applications were primarily research endeavors, with the goal of creating mechanisms that can achieve the benefits of vcr reliably, durably and for reasonably low cost. Variable compression ratio engines have great potential to increase engine power and fuel economy. Infinitis new vct changes the rules of small turbocharged. Check out animations of the mechanisms at work in our story where we. Effect of compression ratio on the performance of diesel.
Infiniti reinvents the gasoline engine vcturbo youtube. Kevin poole schaefflers variable compression ratio actuator system 2018 schaeffler symposium 962018 18 actuator system simulation optimization strategies. Sep 04, 2016 angle position of orange control shaft is controlled by a motor not shown. More than 20 years in development, the vcturbo uses an advanced multilink system to change the compression ratio. Aug 28, 2011 the engine made by mce 5 offers a variable compression ratio, offering improved performance with fewer emisions and less consumption. Variable compression ratio was achieved by raising or lowering the cylinder and cylinder head of the engine relative to the crankshaft. Sep 05, 2017 the worlds first production variable compression ratio engine comes from infiniti also, check out how it works here, and now it appears toyota has also been working on a similar idea. Infiniti showed off a slightly updated q50 yesterday at the paris motor show, but nobody gave a damn because right next to it was this. Dont get me wrong, the worlds first productionbound variable compression internal combustion engine is truly something. A free powerpoint ppt presentation displayed as a flash slide show on id. Thermal efficiency refers to the power an engine generates from a unit of fuel. Nissans crafty engine ends a century of compromise wired. This engine tries to solve the problem of being both a small, fuelefficient engine and a large, powerful engine by changing its geometry. At low power output, the engine can be made to operate as a high compression ratio naturally aspirated engine.
Coupled dynamic simulation of two stage variable compression ratio vcr connecting rod using virtual dynamics 2019260031 the fuel consumption of combustion engines requires continuous reduction to meet future co2 fleet targets. This technology took them more than two decades to perfect. Dec 04, 2017 under the hood infiniti debuts breakthrough engine technology in new qx50 its the worlds first production variablecompression ratio engine. This turbocharged gasoline engine can switch compression ratios on the fly. A study of a variable compression ratio and displacement mechanism using design of experiments methodology shugang jiang, michael h. A close look at infinitis vcturbo variable compression.
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