Variable compression ratio

Nissan says that the turbo-charged, 2-liter, four-cylinder VC-T engine averages 27 percent better fuel economy than the 3. Unlike the Peugeot design, the effective con-rod length is fixed.

Compression ratio

This facilitates a reduction in friction losses and weight and allows more freedom in the design of intake and exhaust ports.

Factors including late intake valve closure relatively speaking for camshaft profiles outside of typical production-car range, but not necessarily into the realm of competition engines can produce a misleadingly low figure from this test.

These designs usually have a second adjustable piston set in the head opposing the working piston. Since then, though carmakers have largely pushed aside variable-compression engines in favor of less-complex technologies, like direct injection, downsized turbocharged engines, and more-efficient transmission designs.

This is a promising sign towards full commercial production readiness and cost-efficient innovative solution which Variable compression ratio change the future of VCR engines.

Cost-efficient and modular applicable

Intake port tuning and scavenging may allow a greater mass of charge at a higher than atmospheric pressure to be trapped in the cylinder than the static volume would suggest This "corrected" compression ratio is commonly called the "dynamic compression ratio".

Lower compression ratio at high load decreases pressures and temperatures at the end of compression. If a problem is suspected, then a more comprehensive test using a leak-down tester can locate the leak.

On the left hand-side of the diagram is the conventional piston of an internal combustion engine. With its unique design, including two hydraulic pistons within a corresponding chamber, the FEV system achieves CR transition within 0.

The pressure shown on a gauge would be the absolute pressure less atmospheric pressure, or This is called scavenging. This gives the best of both worlds, a small efficient engine that behaves exactly like a modern family car engine but turns into a highly tuned one on demand.

Earlier variable compression engines have been highly desirable but technically unobtainable for production vehicles due to the mechanical complexity and difficulty of controlling all of the parameters. That lets the engine adjust moment by moment to torque demands, always maintaining top efficiency.

However, new solutions like Waulis approach does not use a second piston and is implemented to existing 4-cylinder engine with minor modifications. The absolute cylinder pressure is the result of an exponent of the dynamic compression ratio.

This acts through a rod-crank system with a gear wheel, whose movement adjusts the effective con-rod length and thus the compression ratio in the left cylinder. This can be done to a greater or lesser extent with massive increases in power being possible. The much higher velocity of a piston when an engine is running versus cranking allows less time for pressure to bleed past the piston rings into the crankcase.

The Peugeot design works by varying the effective length of the con-rods connecting the piston to the crank. Under ideal adiabatic conditions, the exponent would be 1.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.

Variable compression ratio

Aug 15,  · Variable compression ratios: Infiniti's new main squeeze. The engine is capable of changing its compression ratio on the fly. Compression ratio is the, er, ratio of maximum to minimum cylinder.

Infiniti plans VC-T engine with variable compression ratio

Infiniti's Variable Compression Gasoline Engine Is Almost Brilliant Apparently, Nissan is pursuing variable compression because electric drivetrains are just too expensive. By. Thus, a variable compression ratio is an adequate measure to limit the required peak firing pressures without negatively affecting the engine’s part load behavior.

In view of modern commonly used boost pressures. Variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. This is done to increase fuel efficiency while under varying loads.

Variable compression ratios: Infiniti's new main squeeze

Higher loads require. The Nissan luxury brand is set to launch a variable-compression engine, which has the ability to alter its compression ratio. DON'T MISS: Porsche Panamera shows just how complex saving fuel.

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Variable compression ratio
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