Variable Cylinder Management

[Blackmask]

The Honda Accord with variable cylinder management has just been launched in Australia. Interesting idea, it can run on 6, 4 or even 3 cylinders depending on the conditions and need.

The VCM system monitors throttle position, vehicle speed, engine speed, automatic-transmission gear selection and other factors to determine the correct cylinder activation scheme for the operating conditions. In addition, the system determines whether engine oil pressure is suitable for VCM switching and whether catalytic-converter temperature will remain in the proper range. To smooth the transition between activating or deactivating cylinders, the system adjusts ignition timing, drive-by-wire throttle position and turns the torque converter lock-up on and off. As a result, the transition between three-, four-, and six-cylinder operation is unnoticeable.

More info here

[Val]

BLACKMASK!!!!

you surprise me with each post of you here. You really are a girl that likes car stuff.
I need a girlfriend in these ways.
At least you will understand me everytime when I'm washing my car instead of visit you!

Well ...

I read once, someting more or less seemed with this you posted.
In the truth, the cylinders will not be shut down completely, because if happen in this way, the car would not work. In this case, the ECU send less pressure and consequently less fuel to the half of the cylinders. Then, the economy should be bigger.

Thanx for the stuff.

[Blackmask]

In the truth, the cylinders will not be shut down completely, because if happen in this way, the car would not work.

hmmm....I don't know if you are completely right there Val. I've had cars in the past that when the engine started to fail lost a cylinder. They still ran, although badly since it was designed to run on 4. Since a car can be designed to run on 3, 4 or 6 cylinders, if Honda has their technology working well it should be possible to completely shut off the cylinders and change the running mode of the car.

The spiel on the VCM technology says that the sparks keep firing to prevent poor combustion when the cylinder valve is opened again.

[Val]

Originally Posted by Blackmask

I've had cars in the past that when the engine started to fail lost a cylinder. They still ran, although badly

Yeah ... was what I wanted to say in other words.
I read about the VCM technology. Is a fuel-saving engine technology. In normal city driving, the engine runs normally off of all six cylinders for the best power and engine response. When smoothly cruising at highway speeds, half of the cylinders are shut off, leaving only three of the cylinders operating.
The 2008 Honda Accord told by you, introduced the second-generation of VCM technology, which can run on three, four or six cylinders for additional fuel savings.
This switchover isn't noticeable to the driver, but it does give a modest gas mileage improvement to the cars equipped with this technology.

I'm not an Engeneer, but in short words I think this can resume ... more or less ... this technology.

[Blackmask]

I saw a brief interview with the President of Honda yesterday during the racing. They have a very strong environmental focus as the way forward with cars so I think they'll get that technology better and better. Honda and Toyota are leading the pack by a long way on fuel efficiency improvements, GM and Ford, as always, are doing what the regs say they have to and will keep falling behind.