CrazyEngineers Forum - Mechanical & Civil Engineering |
- Camless Engine: It would save fuel, run cleaner and more,,,
- Spark Plugs are passe - Here come the Laser Igniter!
- About Bolts and Nuts - What else in CE? A simpler way to predict bolt preload
| Camless Engine: It would save fuel, run cleaner and more,,, Posted: 17 May 2011 01:17 PM PDT Good evening mates, Most four-stroke piston engines today employ one or more camshafts to operate poppet valves. The lobes on the camshafts operate cam followers which in turn open the poppet valves. A camless (or, free valve engine) uses electromagnetic, hydraulic, or pneumatic actuators to open the poppet valves instead. Actuators can be used to both open and close the valves, or an actuator opens the valve while a spring closes it. As a camshaft normally has only one lobe per valve, the valve duration and lift is fixed. The camshaft runs at half the engine speed. Although many modern engines use camshaft phasing, adjusting the lift and valve duration in a working engine is more difficult. Some manufacturers use systems with more than one cam lobe, but this is still a compromise as only a few profiles can be in operation at once. This is not the case with the camless engine, where lift and valve timing can be adjusted freely from valve to valve and from cycle to cycle. It also allows multiple lift events per cycle and, indeed, no events per cycle—switching off the cylinder entirely. Camless engines are not without their problems though. Common problems include high power consumption, accuracy at high speed, temperature sensitivity, weight and packaging issues, high noise, high cost, and unsafe operation in case of electrical problems. Source: Camless - Wikipedia, the free encyclopedia In camless engines the method will simply be solenoids and sensors and some magnetic actuators (I don't have sufficient details). However, there is a rumour saying that BMW will be the first to release it on its 3-series cars ;) cheers, |
| Spark Plugs are passe - Here come the Laser Igniter! Posted: 17 May 2011 08:34 AM PDT Lasers aim to spark revolution in internal combustion engines Designfax, Tech for OEM Design Engineers |
| About Bolts and Nuts - What else in CE? A simpler way to predict bolt preload Posted: 16 May 2011 07:03 PM PDT A simpler way to predict bolt preload Generalized torque coefficients and a universal torque table give engineers an easier path to accurate bolt preloading. A simpler way to predict bolt preload | Machine Design Images are clickable for enlarging. |
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