Solenoid valve operation in the Noughties

[Tim203]

Can anyone remember Mercedes announcing the launch of a new engine in the c class at this time. I was curious as I knew that other manufacturers had already done work on this but it all went quiet and nothing more was mentioned.

 

[190]

I thought electrical valve operation was only going to be feasible when car electrical systems raise their voltage from 12 volts to 24 or 48 volts. That will reduce the current drawn and allow some components to be smaller.

Is a change in system voltage still on the cards.

 

[grober]

It was proposed at one point for the new W204 C class !!! It was called KDI EVT --came out first I believe around the same time as that steering by joystick thingy.

Camless engine

Siemens Automotive is developing a second-generation electromagnetic valve train (EMVT). The full-load capability of the system at maximum speeds has already been demonstrated in a 16-valve four-cylinder engine. The key component of the infinitely variable electromechanical valve train is an armature-position sensor that simultaneously assures energy- and noise-reducing-control characteristics. Each actuator has a position sensor and is individually electronically controlled. In this manner, the valve timing can be adjusted as required within the physical limits of actuator operation. Thus, this valve control technology results in reduced fuel consumption and emissions as well as improved torque in spark-ignited engines.

The demonstration engine on a test dynamometer in Regensburg, Germany, is equipped with 16 valve actuators and the corresponding armature-position sensors, the Electronic Valve Control Unit (EVCU), a modified engine management Electronic Control Unit (ECU), and two cable rails connecting the actuators to the EVCU. The engine control transmits the actuator signals to the valve control system via a CAN bus. The system operates with an electrical distribution system voltage of 42 V generated by a crankshaft-mounted starter-generator.

The actuators work according to the free spring-mass-oscillator principle. A special software algorithm is used to control the actuator coil currents so that the valves are decelerated to a speed near zero as they land - in conjunction with a switching time of barely three milliseconds. It was this very soft landing feature that permitted the advantages of a cam-controlled valve train - soft touchdown of the valves on the valve seat - to be transferred to the electromechanical principle.

For the valves this means minimal wear and minimum noise generation. Without a software-based problem solution, the increased force exerted by the solenoid on the armature pole face as the air gap diminishes would result in very high impact speeds. This would produce mechanical and acoustic loads that would preclude continuous system operation.

The EVCU's other responsibility - in addition to managing valve timing - is to take on actuator-specific tasks such as the current control in the actuator coils. The armature-position sensor installed in the actuator housing also supplies the current values using a safe actuator control mechanism and provides important diagnostic information.

More details here.


AutoSpeed - Camless Engines

 

[Bellow]

Can anyone remember Mercedes announcing the launch of a new engine in the c class at this time. I was curious as I knew that other manufacturers had already done work on this but it all went quiet and nothing more was mentioned.

I'm pretty sure I read recently that MB abandoned solenoids precisely because it didn't go quiet - ie the noise issue was insurmountable.

I thought electrical valve operation was only going to be feasible when car electrical systems raise their voltage from 12 volts to 24 or 48 volts. That will reduce the current drawn and allow some components to be smaller.

Is a change in system voltage still on the cards.

There was a lot of talk of upping operating voltages but currently a great deal of resistance is shown toward it. I notice electric turbochargers being developed and the manufacturers being pleased as punch with themselves that they have achieved their objectives utilising 12V. Why the change in attitude (if I was truly chasing electrical puns I would have inserted the obvious right there) I don't know.

 

[zoona]

Konigsegg have been playing with it too.

https://youtu.be/Bch5B23_pu0