Camless engines design

Replies

• 

  satheesh27887

  R U Trying To Eliminate The Cam Used To Control The Opening And Closing Of Inlet And Outlet Valves.....
  Or Something Else.......
• 

  Differential

  How about electronically controlling the opening and closing of valves ?
• 

  gohm

  great project! Anything is practically feasable if your budget is big enough. What are your plans on this? Which cam-less meathod are you planning on?
• 

  geococeo

  well you should definetely check out two strokes because many older ones i have seen use valve sleeves built into the block so that the action of the piston reveals(opens), also i think wankel motors are camless tho i dont know much about them it does not seem to me that they would need cams??
  let me know what inventions you come up with...
• 

  ratnaji

  The objective of the project was to design and manufacture a device that proved the concept of a CLE. More specifically, it is a electro/hydraulic device capable of producing engine valve displacement at typical automotive demands.
  The system design utilized a customized piezoelectric stack and hydraulic spool valve combined with an in-house designed hydraulic amplifier. Control is facilitated by a function generator, and feedback is monitored with an oscilloscope.
  
• 

  ratnaji

  The objective of the project was to design and manufacture a device that proved the concept of a CLE. More specifically, it is a electro/hydraulic device capable of producing engine valve displacement at typical automotive demands.
  The system design utilized a customized piezoelectric stack and hydraulic spool valve combined with an in-house designed hydraulic amplifier. Control is facilitated by a function generator, and feedback is monitored with an oscilloscope.
  
• 

  santu81

  any one who is final year mechanical engg .. can make project with co-ordination of ISRO . ISRO runs a programme viz.. RESPOND . you can contact them and make your project with guidence.
• 

  manik627

  Camless engines are now very old. The new CRDI engines in cars uses this technology. Many of the newest marine propulsion engines are camless.
  
  This tech. uses a common rail pressurised and using timed controls injecting fuel.
• 

  amrit5605

  i mech. 4th yr and want to know details about camless engine plz anybody help me
• 

  ratnaji

  Can you give me some more information about the camless engines? I see the topic being discussed in mechanical engineering quite often.
• 

  vaitheeswaran

  For the project work regarding camless engines you may have to use this formula for detecting the value of L. L=(P+S+D)/2
  P= Length of piston
  S= length of valve stroke required
  D=Diameter of the port
  L= minimum length from bore centre line to port centre line. on using this and the resulting theoretical value will help you check out the feasibility..
• 

  ajay99

  i also need same info can anybody give in detail
• 

  ShrinkDWorld

  Camless engines are now very old. The new CRDI engines in cars uses this technology. Many of the newest marine propulsion engines are camless.
  
  This tech. uses a common rail pressurised and using timed controls injecting fuel.

  can you tell me more information about CRDI engine ??????
• 

  gohm

  There is a ton of stuff out there if you type crdi in a search engine, start with this:
  
  Crdi
• 

  yashit

  yes it is possible. for this knowledge of electronics is required.
  
  cams are in four stroke engines and used for valves opening n closing.
  so u need electronic device which evaluates that at wat time open the valve n closing time.
  
  and then to operate a mechanical device to operate valve. there are following design:-
  
  1. mechanical actuator
  2. concept of screw drive can be used
  etc.
  
  this is as per my knowledge if this can help you then it wil be a pleasure for me.
• 

  Red Hawk

  First of all, We all have to think one thing before suggesting any ideas here.. Before doing any projects or opting for any papers we have to analyse it thoroughly.. What is the disadvantage of having cams here? Why do we want to eliminate cams? If there is any suitable answer like 'it increases the fuel efficiency' or 'it reduces the stroke timings', please post them here with references.. It would be greatly helpful..
• 

  gohm

  less moving parts= more efficient, fewer points of failure system
• 

  nautyjaggu

  CAM-Less ENGINES
  
  
  
  The development of cam in automobiles has been the important part of engine, as it opens and closes the valve at a required timing. The conventional valve train consists of a cam, a rocker arm and tappet assembly. For maximum efficiency of valve
  engine, overlapping of valve opening and closing proved necessary. Studies have shown that use of cam offers a compromise between maximum power and fuel economy.
  
  This lead to the concept of Camless engine where both maximum efficiency and power can be achieved simultaneously.
  
  Camless engine technology is soon to be a reality for mass-produced vehicles. In the camless valvetrain, the valve motion is controlled directly by a valve actuator - there's no camshaft or connecting mechanisms.
  
  Various studies have shown that a camless valve train can eliminate many otherwise necessary engine design trade-offs.
  
  Automotive engines equipped with camless valvetrains of the
  • electro-hydraulic and
  • electro-mechanical type
  have been studied for over twenty years, but production vehicles with such engines are still not available.
  
  The issues that have had to be addressed in the actuator design include:
  • reliable valve performance
  • cost
  • packaging
  • power consumption
  • noise and vibration
  
  Disadvantages of CAM
  
  • The cam is rotated by camshaft, which in turn
  operate the valve that means there are three
  siblings (tappet, cam and rocker) in cam and
  valves. As stages in motion transmission
  increases the power loss due to friction increases
  ultimately reduction in output of the engine.
  • Frequent use of cam lead to change in shape of
  cam which affects valve timing. Due to this the
  valves opens later and closes before the actual
  desired time. This results in less volumetric
  efficiency improper combustion and ultimately
  detonation in Spark Ignition (SI) engine.
  • Valve timing diagram at slow speed and high
  speed are different, which reduces flexibility of
  engine.
  • Metal to metal contact lead to noise and thermal
  losses.
  • Cam design need to compromise between
  maximum efficiency and power, which lead to
  compromising major factors while designing
  engine.
  • In conventional engine the push rod and rocker
  arm impose some inertia, which affects valve
  action and pose limit on top engine speed.
  
  
  
  
  Camless Valvetrain Operation
  1. Electromechanical Valves
  • Conventional type
  • Ball valve setup
  
  a) Conventional type:
  This type of system uses an armature attached to the valve stem.The outside casing contains a magnetic coil of some sort that can be used to either attract or repel the armature, hence opening or closing the valve.
  
  
  
  
  
  A magnetic field is generated by a magnetic field generator and is directed across the fixed air gap. An armature having a current-carrying armature coil is exposed to the magnetic field in the air gap. When a current is passed through the armature coil and that current is perpendicular to the magnetic field, a force is exerted on the armature.When a current runs through the armature coil in either direction and perpendicular to the magnetic field, an electromagnetic vector force, known as a Lorentz force, is exerted on the armature coil. The force generated on the armature coil drives the armature coil linearly in the air gap in a direction parallel with the valve stem. Depending on the direction of the current supplied to the armature coil, the valve will be driven toward an open or closed position
  
  b) Electromechanical Ball Valves:
  This type of electromechanical valve system consists of a ball through which a passage passes. If the ball is rotated such that the passage lines up with other openings in the valve assembly, gas can pass through it. (Exactly like the ball valves many of us use to control our boost.) Opening and closing the valve is accomplished by electromagnets positioned around its exterior.
  
  
  
  • the valve housing (7) is shown in two pieces.
  • Ball valve (8)
  • has two rigidly attached pivots (12).
  • The disc (10)
  is permanently attached and indexed to the ball valve and contains permanent magnets around its perimeter.
  • The electromagnets (11)
  • are situated on both sides of the ball valve (8)
  and they are fixed to the valve housing.
  
  
  The substitution of a simple, efficient ball valve and valve housing arrangement in a a four stroke reciprocation piston engine eliminates all the independent moving parts in the valve train. This may even be an improvement over the poppet valve camless system - the ball valve needs only to rotate on its axis to achieve the desired flow conditions, rather than be accelerated up and down in a linear fashion. A partially open ball valve state may also be able to be used to create more turbulence.
  
  
  2.Electrohydraulic Poppet Valves
  The basic design of the electrohydraulic valvetrain hardware is illustrated in Figure 11.
  
  • The engine poppet valves (22) and the
  • valve springs (24) that are used to reset
  them are shown.
  The poppet valves are driven by
  • hydraulic actuators (26), which are controlled
  by electrically operated
  • electro-hydraulic valves (28) supplying
  hydraulic fluid to the actuators via
  • conduit (29). The preferred hydraulic fluid is
  engine oil, supplied to the electro-hydraulic valves by the
  • pressure rail (30). An engine-driven
  • hydraulic pump (32) supplies the oil pressure, receiving the oil from the
  • engine oil sump (34). The pump output
  pressure is also limited by an
  • unloader valve (36), as controlled by an
  • accumulator (38) connected to the oil
  pressure rail. With this design the hydraulic pump could be periodically disconnected, such as under braking, so that the valve train would run off the stored accumulator hydraulic pressure.
  
  
  
  Benefits of CAM-less engines
  
  1. Better Fuel Efficiency:
  Prototype design offers tremendous opportunities in fuel efficiency. In conventional engines, eventually 25-27% of fuel (Petrol or Diesel) is utilized in creating actual driving force of the vehicle. But in ECVAS, it has increased by 10-30%. This is only because of decrease in losses such as friction, wear and tear, thermal loss in camshaft mechanism.
  2. Higher Output:
  It directly relates with power and torque of an engine.
  Frictional losses in valve actuating mechanism are
  reduced. Thus it improves output power and mechanical efficiency.
  Torque - There is no need of operating torque to operate Camless valve train, hence power consumption reduces.
  3. Performance of Engine:
  This mechanism allows engine for valve sequencing changes in conjunction with changes in driving of the vehicle i.e. at any torque or at any speed of the engine. As in conventional engine we found economy speed to drive out better mileage of the engine. ECVAS overcomes above problem by optimizing engine performance at any speed, as the valve actuation is on battery.
  
  
  4. Reduction of Emission:
  As the valves actuate in accordance with practical valve timing diagram of the engine, there is perfect combustion of air-fuel mixture. Thus, the gases are completely combusted. As there is no metal to metal contact, which lead to considerable reduction in sound emission. Thus it behaves as a complete EURO-II actuation with higher compatibility.
• 

  gohm

  good info, can you share the source?
• 

  nautyjaggu

  CAM-Less ENGINES
  
  
  
  The development of cam in automobiles has been the important part of engine, as it opens and closes the valve at a required timing. The conventional valve train consists of a cam, a rocker arm and tappet assembly. For maximum efficiency of valve
  engine, overlapping of valve opening and closing proved necessary. Studies have shown that use of cam offers a compromise between maximum power and fuel economy.
  
  This lead to the concept of Camless engine where both maximum efficiency and power can be achieved simultaneously.
  
  Camless engine technology is soon to be a reality for mass-produced vehicles. In the camless valvetrain, the valve motion is controlled directly by a valve actuator - there's no camshaft or connecting mechanisms.
  
  Various studies have shown that a camless valve train can eliminate many otherwise necessary engine design trade-offs.
  
  Automotive engines equipped with camless valvetrains of the
  • electro-hydraulic and
  • electro-mechanical type
  have been studied for over twenty years, but production vehicles with such engines are still not available.
  
  The issues that have had to be addressed in the actuator design include:
  • reliable valve performance
  • cost
  • packaging
  • power consumption
  • noise and vibration
  
  Disadvantages of CAM
  
  • The cam is rotated by camshaft, which in turn
  operate the valve that means there are three
  siblings (tappet, cam and rocker) in cam and
  valves. As stages in motion transmission
  increases the power loss due to friction increases
  ultimately reduction in output of the engine.
  • Frequent use of cam lead to change in shape of
  cam which affects valve timing. Due to this the
  valves opens later and closes before the actual
  desired time. This results in less volumetric
  efficiency improper combustion and ultimately
  detonation in Spark Ignition (SI) engine.
  • Valve timing diagram at slow speed and high
  speed are different, which reduces flexibility of
  engine.
  • Metal to metal contact lead to noise and thermal
  losses.
  • Cam design need to compromise between
  maximum efficiency and power, which lead to
  compromising major factors while designing
  engine.
  • In conventional engine the push rod and rocker
  arm impose some inertia, which affects valve
  action and pose limit on top engine speed.
  
  
  
  
  Camless Valvetrain Operation
  1. Electromechanical Valves
  • Conventional type
  • Ball valve setup
  
  a) Conventional type:
  This type of system uses an armature attached to the valve stem.The outside casing contains a magnetic coil of some sort that can be used to either attract or repel the armature, hence opening or closing the valve.
  
  
  
  
  
  A magnetic field is generated by a magnetic field generator and is directed across the fixed air gap. An armature having a current-carrying armature coil is exposed to the magnetic field in the air gap. When a current is passed through the armature coil and that current is perpendicular to the magnetic field, a force is exerted on the armature.When a current runs through the armature coil in either direction and perpendicular to the magnetic field, an electromagnetic vector force, known as a Lorentz force, is exerted on the armature coil. The force generated on the armature coil drives the armature coil linearly in the air gap in a direction parallel with the valve stem. Depending on the direction of the current supplied to the armature coil, the valve will be driven toward an open or closed position
  
  b) Electromechanical Ball Valves:
  This type of electromechanical valve system consists of a ball through which a passage passes. If the ball is rotated such that the passage lines up with other openings in the valve assembly, gas can pass through it. (Exactly like the ball valves many of us use to control our boost.) Opening and closing the valve is accomplished by electromagnets positioned around its exterior.
  
  
  
  • the valve housing (7) is shown in two pieces.
  • Ball valve (8)
  • has two rigidly attached pivots (12).
  • The disc (10)
  is permanently attached and indexed to the ball valve and contains permanent magnets around its perimeter.
  • The electromagnets (11)
  • are situated on both sides of the ball valve (8)
  and they are fixed to the valve housing.
  
  
  The substitution of a simple, efficient ball valve and valve housing arrangement in a a four stroke reciprocation piston engine eliminates all the independent moving parts in the valve train. This may even be an improvement over the poppet valve camless system - the ball valve needs only to rotate on its axis to achieve the desired flow conditions, rather than be accelerated up and down in a linear fashion. A partially open ball valve state may also be able to be used to create more turbulence.
  
  
  2.Electrohydraulic Poppet Valves
  The basic design of the electrohydraulic valvetrain hardware is illustrated in Figure 11.
  
  • The engine poppet valves (22) and the
  • valve springs (24) that are used to reset
  them are shown.
  The poppet valves are driven by
  • hydraulic actuators (26), which are controlled
  by electrically operated
  • electro-hydraulic valves (28) supplying
  hydraulic fluid to the actuators via
  • conduit (29). The preferred hydraulic fluid is
  engine oil, supplied to the electro-hydraulic valves by the
  • pressure rail (30). An engine-driven
  • hydraulic pump (32) supplies the oil pressure, receiving the oil from the
  • engine oil sump (34). The pump output
  pressure is also limited by an
  • unloader valve (36), as controlled by an
  • accumulator (38) connected to the oil
  pressure rail. With this design the hydraulic pump could be periodically disconnected, such as under braking, so that the valve train would run off the stored accumulator hydraulic pressure.
  
  
  
  Benefits of CAM-less engines
  
  1. Better Fuel Efficiency:
  Prototype design offers tremendous opportunities in fuel efficiency. In conventional engines, eventually 25-27% of fuel (Petrol or Diesel) is utilized in creating actual driving force of the vehicle. But in ECVAS, it has increased by 10-30%. This is only because of decrease in losses such as friction, wear and tear, thermal loss in camshaft mechanism.
  2. Higher Output:
  It directly relates with power and torque of an engine.
  Frictional losses in valve actuating mechanism are
  reduced. Thus it improves output power and mechanical efficiency.
  Torque - There is no need of operating torque to operate Camless valve train, hence power consumption reduces.
  3. Performance of Engine:
  This mechanism allows engine for valve sequencing changes in conjunction with changes in driving of the vehicle i.e. at any torque or at any speed of the engine. As in conventional engine we found economy speed to drive out better mileage of the engine. ECVAS overcomes above problem by optimizing engine performance at any speed, as the valve actuation is on battery.
  
  
  4. Reduction of Emission:
  As the valves actuate in accordance with practical valve timing diagram of the engine, there is perfect combustion of air-fuel mixture. Thus, the gases are completely combusted. As there is no metal to metal contact, which lead to considerable reduction in sound emission. Thus it behaves as a complete EURO-II actuation with higher compatibility.
  😁😁😁😁😁😁😁😁😁😁
• 

  veena912

  when u are dealing with electro-mechanical valves noise may be a big problem . because the valve actuator parts may move in high speeds so it has to be muffled.
• 

  nautyjaggu

  gohm

  good info, can you share the source?

  
  From a number of sites.......
  cant remember them.......
• 

  nautyjaggu

  veena912

  when u are dealing with electro-mechanical valves noise may be a big problem . because the valve actuator parts may move in high speeds so it has to be muffled.

  
  
  Got anymore details??????
  Please help me if possible.
  Thanx.........
• 

  gohm

  Ok, just want to be sure as there were links and reference to diagrams that were left out so I wanted to make sure if we were using another source for the information that it receives credit and is noted.
  
  

  nautyjaggu

  From a number of sites.......
  cant remember them.......

• 

  jhbalaji

  There for have a look here mate
  
  #-Link-Snipped-#
• 

  michaelakbar

  ratnaji

  hi! friends.i am final year mech engg now.
  i want to do project on camless engines. Is it practically feasible?
  please help me in this regard.
  please help me.....

  plz explain in breif...what u r going 2 make change in engine design nd construction