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RVCR – Roto-Dynamic Variable Compression Ratio

The invention of RVCR and is Technology is related to Mechanism for ‘Fluid Handling Machines’ (FHM) used primarily for Prime-Mover Applications which is Engines and Renewable Energy Power Generators.

The Applications include an entire spectrum of Products over a wide range of sectors and during the Technology development process the structure (Click for more on the structure) to enable customization and scaling up and down for the adapting to the requirements of different applications. The customization of technology to deliver a sector specific application product would necessitate a dedicated Project.

RVCR provides for commercially viable Green solution to 21st century global fossil fuel concern & energy paradox, by making superior engineering products (Automotive Engines, Compressors, Pumps, Wind & Hydro-Electric Power-Generators) compared to conventional equivalents, in terms of cost, utility & carbon footprint.

RVCR Applications

RVCR I.C. Engines

RVCR mechanism is a superior alternative to the century old ‘Slider Crank mechanism’ that combines the efficiency gains of ‘Positive Displacement mechanism’ and the Compactness of ‘Rotary Mechanism’ and deliver the long pursued and illusive feature called ‘Variable Compression Ratio’ (VCR) in Engines.

The RVCR mechanism is an entirely new dimension in Kinematics (Click for Details) and the sequential motion of the various components (Links) requisite to fructify the mandatory Gas Processes in I.C. Engines is achieved in a smarter, compacter way. The conventional reciprocating motion of cylindrical piston is a source of major limitations and RVCR eliminates it. The piston and the liner are bent wherein the piston when sliding in the liner is a rotary motion which is directly transferred to a central shaft.

It yields a whole new method to control the quality of fuel combustion and the way energy is converted to torque and outputs several unprecedented capabilities in engines which is summarized below.

Radical New Capabilities

  • RVCR allows analogous ‘Compression Ratio’ (CR) variation to suit the fuel opted to drive the engine.
  • Reduce consumption by real time VCR to deliver peak efficiency over entire Load Range.
  • Increased Specific Power through Multiple Double-acting Pistons in One single continuous enclosed Liner & 100 % Mechanical Leverage.

Unique Capabilities

  • Enhanced thermodynamic Efficiency from Constant Volume Heat addition and removal.
  • Slow Speed High Expansion rate with Low heat dissipation surface area
  • High Specific Power through Multiple Double-acting Pistons in a single continuous Liner.

It costs less for making an RVCR engine of equivalent power rating to that made using conventional crank mechanism, for the reduction in the total amount of Material and the number of Manufacturing processes required.

The downsizing improves on the Power to weight drastically and the degree of compactness increases with Power Rating.

RVCR Design provides the flexibility to manipulate the volume in 3 dimensions to suit to volume and space requirements.

RVCR Technology marks a quantum leap in combustion efficiency using Roto dynamic analogous variation of combustion chamber volume/pressure hence, introducing the first ever complete 3 element controls in combustion mechanism namely :

  • Quantitative & qualitative fuel control
  • Heat & temperature control
  • Air /charge pressure/density control

Click here for Layman Description

Unique Atrributes

  • 1st ever Viable use of ‘VCR’ Feature and achieving ‘CVHA’; and Improved thermodynamic process.
  • Single & Single Stroke Engines (2, 4 stroke equivalents).
  • Multiple Units in One Continuous Liner enclosure.
  • Downsizing of Engines by improved compactness from above mentioned factors.
  • Reduced weight to power ratio from above mentioned factors.
  • Elimination of side Thrust and 2nd order Vibrations by Rigidly held pistons (Doesn’t float on gudgeon).
  • Eliminates use of dedicated heavy fly wheels due to elimination of ‘Reversal of Inertial forces’ and Turning Moment.

Click here for Benefits
Click here for Comparison with Competing Engine Technologies

RVCR Wind Energy Power Generation

The RVCR is an entirely new Principal in Prime-Mover Drive Mechanism that that enable multi-fold increase in energy capture efficiency compared to modern wind turbines. The RVCR principal simplifies the mechanics of Prime-Mover to reduce the Capital Cost drastically and the engineering involved reduces operations cost.

The Conventional wind turbines are driven by lift, achieved by aero foil profile of turbine blades. The axial flow wind turbines are rotary machines converting the Kinetic Energy of Wind into Power. RVCR is a rotary positive displacement mechanism that uses pressure differential between high wind velocity zone and ground level stagnant air conditions.

Unique capabilities

Departure from Convention

  • Power Unit Installation on Ground.
  • No Open rotating blades.
  • Quieter operation, No Bird hazards.
  • Gyroscopic couple eliminated.
  • City building Embedded installation.

Claiming Climate Energy

  • No lock-down during storm force wind.
  • RPM control by air-flow Bypass.
  • Torque control by Vane displacement.
  • No yaw Gear.
  • No synchronous gearbox.

The Value Proposition

  • RVCR reduces Levelized cost of Power and revolutionizes the wind Power Prime-Movers to be a highly potent and viable means for claiming a much larger share of Power Production and Energy Market.
  • RVCR liberates large wind energy production units form geographical constraints “Out of city and Populated areas) and enable city based embedded Power Generation units.
  • RVCR wind motors are highly compact and easy to handle so, with lower manufacturing cost leading to lower capital investment.

The Principle

RVCR wind Motor configuration converts higher wind velocities at elevated levels into low pressure communicated through a wind stack to higher air pressure at ground level ('near zero air velocities) and utilizes RVCR wind motor (Prime Mover) at lower end of the stack to tap into the flow in the rising column of air for power generation. This is made possible due to key attributes of RVCR methodology in simplifying the means to achieve a ‘Rotary Positive Displacement Mechanism’.

RVCR Viability

RVCR enables Wind Power driven Prime-Movers Systems embedded into modern high-rise city structures to overcome constraints of large wind turbine based Renewable Power installations to out-door locations.

‘Pressure differential’ is a scalar quantity independent of fluid flow direction which eliminates the yawing, furling and stalling related accessories, thence drastically reducing complex structural requirements necessary for conventional turbines. RVCR reduces remote locale related costs (transportation, installation, distant power transmission infrastructure) coupled with enhanced efficiency of energy conversion making it a cost effective, pragmatic, high efficiency, green captive power unit.

The simplicity and ease of installation at point of power demand and consumption of RVCR Wind motor power generator units, empowers rural populace with energy self-sufficiency at minimal cost of erection and maintenance hence improving the local economy into self-sufficient independent rural communities.

The Impact

A source of round the clock, self-sufficing economic power generation unit at proximity, eliminates the extremely demanding energy concerns of populace in general that provides for independence towards tapping the enormous opportunities available locally, leading to a continual upgrading cycle of improved standard of living.

RVCR Wind motor is a pragmatic, cost effective, zero emission power generating unit, hence free of green-house gases to address 21st century global environmental concerns.

RVCR wind power motors are better, efficient machines compared to conventional wind turbines.

The RVCR Wind Motor device was 1st conceived mid-way during the RVCR Preliminary Engine Prototype Development project is an off shoot of the base RVCR Technology.

Unique Atrributes

  • Wind flow energy Pressure Differential derived form as the Drive Force.
  • Eliminates need for installation of Prime-mover and generator at elevated Position.
  • Elimination of Yaw Gear for wind Flow Direction alignment for Maximising Energy Capture.
  • Downsizing of Prime Mover and Generator to a fractional size of conventional Turbines.
  • Stress on Rotary Components Reduced to Negligible Level with elimination of Elongated Cantilever.
  • Reduced Material Usage.
  • Easy of Control of RPM by reduction of Pressure Differential.

Click here for RVCR Wind Motor Details & Advantages
Click here for Comparison with Conventional Turbine Technology

RVCR Hydro-Kinematic Power Generation

An entirely new Principal in Prime-Mover Drive Mechanism that that enable multi-fold increase in energy capture efficiency compared to modern wind turbines. The RVCR principal simplifies the mechanics of Prime-Mover to reduce the Capital Cost drastically and the engineering involved reduces operations cost.

The Conventional Hydro Kinematic system use turbines to extract drive power from flow energy in canals, rivers etc.

RVCR HKPG is a new method is a rotary positive displacement mechanism that uses pressure differential created from flow energy of water as a drive force.

Click to enlarge the diagram

Unique capabilities

RVCR Hydro Power Generators (HPG)

Departure from Convention

  • On shore Installation of Power Unit.
  • No open water rotating blades.
  • No hazards to natural Hydrology
  • No Gyroscopic force related equipment.

Claiming Climate Energy

  • No lock-down during storm force wind.
  • RPM control by water flow Bypass.
  • Torque control by Vane displacement.
  • No yaw Gear and syncs gearbox.

The Value Proposition

  • RVCR HKPG reduces Levelized cost of Power and revolutionizes the Hydro Power Prime-Movers for claiming a much larger share of Power Production and Energy Market.
  • RVCR HKPG design enables ‘shore or dry installation’ of prime-Mover and generation units. The submerged units are provisioned with a Buoyancy ballast for retrieving units for maintenance and operations. This makes maintenance cost effective and lowers long term operations cost.
  • RVCR Hydro motors are highly compact and easy to handle so, with lower manufacturing cost leading to lower capital investment.

RVCR HK Mechanism Principle

Hydro-Kinematic Power Generator (HKPG) is a Positive Displacement Rotary Mechanism which utilizes pressure differential created by the water current made to flow through a convergent divergent nozzle. A fluid flow induced by pressure differential between two different points is routed through the flow channels of RVCR-HK, where in it works against a rotating vane inside an enclosed chamber by pushing it and creating torque on a shaft to generate continuous output torque.

The RVCR Hydro Kinematic Prime-Mover Project is based on the invention titled ‘Fluid Driven Prime-Mover’ and which covers both the hydro cum wind Motors inventions. The Project to develop its technology was 1st conceived as a joint endeavor with the university of Maryland, and through funding from INDO US Science and Technology Fund.

Unique Atrributes

  • Water flow energy Pressure Differential derived form as the Drive Force.
  • Eliminates need for installation of Prime-mover and generator at elevated Position.
  • Elimination of Yaw Gear for wind Flow Direction alignment for Maximising Energy Capture.
  • Downsizing of Prime Mover and Generator to a fractional size of conventional Turbines.
  • Stress on Rotary Components Reduced to Negligible Level with elimination of Elongated Cantilever.
  • Reduced Material Usage.
  • Easy of Control of RPM by reduction of Pressure Differential.

Click here for Hydro Motor Description & Advantages


Pumps are an essential part of processes dealing with fluids in industrial processes, domestic use machines or other societal use like waste water handling etc. They are placed in the fluid flow path where the fluid enters and exits from different points on the Pump. A pump acts on the fluid mainly in two different ways resulting in two different types of pumps listed below;

  • The 1st type: - fluid is trapped within the spaces between the moving and stationary elements of the Pump and are transported from the Inlet/entry Point to the exit point. These types of Pumps are known as 'Positive displacement' type Pump. The name derives from the fact that, whatever fluid enters the pump is positively displaced from the entry side to exit and can neither return to the entry side nor stay inside the pump. whatever goes in will come out of the pump. These are used for transport fluid from one place to other.
  • The 2nd type is where the fluid is churned by a fast spinning element like a propeller which agitates the fluid and is hence thrown outwards and channelled to the outlet. It the out let is closed the fluid will remain inside the pump and keeps on churning. These Pumps are known as rotary/dynamic pumps. Generally used for pumping large amount of fluid but the quantity is not exactly metered.

The volume transferred by 1st type of pump is easily metered as it is in multiples of the volume entrapped. (Volume multiplied by rotations or strokes), but it is not easy to calculate the amount of fluid churned out of the 2nd type of pump. In Industrial and other processes, the fluid demand changes dynamically and various methods are used to deal with such varying demand like (Starting of multiple Pumps for increased flow or say by parting the flow into multiple channels and allowing some channels to flow fluid back to the inlet side.

Pumps based on RVCR

RVCR system for the 1st time allows a wide range variation in the volume entrapped within a positive displacement pump and hence can adjust the output of the pump according to the process demand. (Idling with minimal flow when fluid demand is minimal and delivering maximum fluid during full load demand). Hence the power consumed for pumping is reduced when the fluid demand is less and only increases when the demand is high. This real time adjusting of fluid flow and hence the power consumed reduces power consumption from the current levels which uses pumps with a constant delivery volume. Moreover, the processes too are well conducted with a easily controlled fluid flow. There are several other benefits of RVCR like large volumes of fluid handled @ low speed hence lower frictional losses etc. Please also note that the RVCR system also makes it possible for various other processes like proportional dosing etc.

Variable Delivery Feature

The feature discussed in the above para is known as Variable delivery. Pumps that can adapt their discharge are known as variable delivery Pump. These are rare pumps and very limited in number used only in very specialized types of applications mostly Hydraulics. The two types are

  • ‘Axial Piston Pump’ or swash Plate Pumps.
  • Hele Shaw Pumps.

The rarity of these pumps is due to the extreme complexity of parts and its intricate assembly. This makes the force Dynamics of these pumps very highly problematic during operations and hence these Pumps are used only in small packs.

RVCR mechanism for the 1st time makes a simple system that deliver ‘Variable Delivery Pumps’. It can achieve variation in flow rate with a simplified mechanism compared to conventional variable delivery pumps. It can be scaled up in large sizes with ease to handle large volumes of fluids. The simplicity of RVCR parts makes it Possible. The simplicity of the design and the large volumes it can handle results in mutli-fold increase in its Flow rate ratio to weight and flowrate ratio to the pump Volume ratio. Hence RVCR can be used to handle fluid on industrial scale in process industry ranging from Waste water treatment to Sludge dewatering and thickening etc.

The specialized applications of RVCR are dosing applications in biomedical applications, metering devises in chemical, food and beverages industry, Breweries etc.

Click here for specialized applications

RVCR Compressor Applications


RVCR compressors are based on a revolutionary 21st century kinematic mechanism, invented and globally patented by Mr. Das Ajee Kamath, which is a superior next generation mechanism alternative to crank mechanism and other rotary positive displacement mechanisms used in compressors across industrial applications. RVCR compressor is a generational leap in terms of features, utility, and efficiency with lower carbon foot prints.

About conventional compressors

Conventionally Reciprocating piston type along with rotary Screw, Lobe/Gear type positive displacement compressors are used for industrial need for various applications like generic high-pressure air, low pressure service air, Refer, Aircon, Industrial Nitrogen, Acetylene, LPG, CNG, etc. Each of these compressors have their advantages and limitations.

Reciprocating compressors are generally not be operated at very high speed due to inertia issues and reversal of piston, and vibration problems, hence limiting its high fluid volume delivering capacity. Further, the reciprocating compressors, utilizes the full upper side of piston area for compression and under-piston side only minimal area can be used for double acting Piston action and the remaining area is open to crankcase. The piston floats on gudgeon, wherein the degree of freedom leads to second order vibrations and chattering. RVCR overcomes all these problems/limitations with its unique rotary mechanism.

In case of Screw compressors, swept volume very limited in size, and for applications which demand high volume flow rates, compressor needs to run at very high speeds. Screw compressors needs clean environment to work because of critical clearances maintained in between sealing surfaces. This type of compressor needs surface sealing and its air ends are not field serviceable.
Lobe/Gear compressors requires timing gears to operate freely. Surface sealing is critical aspect in this type. As slip is more with thin fluids through surface sealing, reduction in slip is a problem with this type. Swept volume of this compressor depends on its size, making it bulky for higher power range.

RVCR Compressors

Based on RVCR technology, the variable delivery volume control feature makes the product highly viable. This compressor is based on Rotary mechanism with two circular but curved piston vanes rotating inside toroidal shaped cylinder, allowing varying compression ratio by adjusting the effective compression stroke volume between these two piston vanes. The vane rotation inside the cylinder is controlled by means of timing devices and linkages, so that the piston vanes either rotate independently, simultaneously or held stationary, in a unique sequence which is the core characteristic of the invention.

Advantages of RVCR Compressors:

RVCR compressors are positive displacement with adjustable compression ratio, offering high- and low- discharge and varying flow rates with single unit. Absence of Crank mechanism assures eliminations of vibrations, which aids to work with high speed.

The rotary compressors normally carry packages of fluid trapped between gears or lobes, similarly in screw compressor the package volume is proportional to the volume covered in 1 pitch of the screw.
This volume is comparatively small as compared to volume displaced by a reciprocating piston. RVCR deploys rotating Piston with no crank mechanism and hence able to increase in volume handled in every stroke by a large amount and especially with increased Bore. Other major advantages of RVCR compressors includes, Low RPM compared to other compressors, with fever moving parts, low maintenance cost, Multistage capability, and heavy-duty work, RVCR compressors are the best option for conventional compressors.

RVCR Applications in specialised Systems

Sewage Sludge Extraction (SSE) system

About Sewage Sludge Extraction (SSE) system for Sludge Dewatering and Thickening

Sewage Sludge Extraction (SSE) is a smaller version of the Slurry dewatering System. It is a novel rotary continuous feed mechanical sludge compression devise that simultaneously sucks, and compress sludge mix, on opposite sides of its internal rotating element in a toroidal chamber, to segregate water and sludge into continuous out flow stream through separate channels. Unlike conventional compression technologies this is a ‘Continuous feed Type’ machine, compact, completely enclosed system (keeping sludge sealed from the operator’s environment to maintain odour free operations) that can operate within power limits of Truck mounted systems. It can easily fit within cylindrical space constraints of regular mobile septic tank emptying units and treat at rates of 3 litres/higher per second within a compact toroidal chamber with self-cleaning separation screens membranes for long maintenance free operation.

The system’s significant technical advancement and inventive step is that this system is 1st of its kind ‘Rotary Positive Displacement’ devise that permits variable volume control between its rotating elements to deliver a compact & highly efficient, simple continuous feed mechanical compression devise with capability for real time variation in the degree of compression based on the type of sludge and to self-adjust the compression ratio to deliver highly thickened sludge from range of inputs.

Description of the technology

Technical Landscape and Comparative Advantages of Sewage Sludge Extraction (SSE)system for Sludge Dewatering and Thickening

Compared to the existing mechanized system this technology and system of dewatering is a robust compact system with the following distinct and unique capabilities

  • Real time adjusting of degree of compression over a wide range of compression ratio allows handling of varying sludge density & Concentration in differing regions without any need for changes in the handling equipment.
  • Simple and Automated method to increase degree of compression during operation to successively increase the density of the sludge to higher levels in multiple loops (if so required) for very high-water content sludge. To easily reduce the intake volume and quantity for thickened sludge.
  • Capable of handling large quantities in a single toroidal volume by use of double acting Plate principal, wherein one side of rotating compressing element compresses sludge and the adjacent side sucks sludge and prepares it for compression. Hence high volumetric efficiency.
  • Easy to clean rinse after operation and backflush the membrane to clean it of clogging.
  • It combines both compression & centrifuging and can easily integrate precise electro treatment of water.

The Design

The technology and mechanism is about a unique arrangement of mechanical links and their pairs for making new machines with fewer and simpler components that can achieve sequential compression and expansion of fluid by decreasing and increasing of enclosed volume.

The sludge will be sucked in space behind the rotating plate-Vane which is increasing and compressed in the chamber ahead of the Plate-Vane which is reducing. As the sludge mix is compressed against the stationary vane and the water is separated through membrane walls placed at locations in the compressed chamber. The pressure within the chamber and the position of the stationary plate vane the sludge valve is opened that allows the sludge to be excreted from the chamber. Considering the water content in the sludge mix the out flow of sludge mixture can be either rerouted to the suction of the unit for further dewatering and as the concentration of the sludge increases so does the pressure in the chamber, which directs the equipment to reduce its compression ratio. The pressure limits of the chamber walls are decided the sludge dryness level required.

The sludge can be treated with electro and other process either within the chamber or latter and provisions for back-flushing of clogged separating membrane can be easily integrated. The entire unknit can be maintained enclosed with the central shaft penetrating the enclosure through a seal. The drive shaft is either power or manual driven where labourers a can crank in case of loss of power or power viability concerns. The unit is portable and can be carried to the location of the sludge and the can internally flushed through for internal inspections if so required. Since all the mechanical clutching and compression ratio parts are controlled externally and not exposed to sludge which remains in the chambers within the equipment. The injection of chemicals and additives can be provisioned if need be within the chamber depending of the desired output specification need of the sludge. The unit is simple, light, robust compact and continuous feed type rapid high flow through put equipment which can achieve very high squeeze pressure if require for highly thickened and dewatered fecal sludge.