How Does The Multi-Displacement System Work?

Question

I'm doing a project and need to know how the Chrysler Multi-Displacement System Works?

Answer 1

The fuel saving comes from a reduction in the pumping loop in the P-V diagram (basic thermodynamic principle for a 4 cycle engine). So like others have said when you are cruising at a steady state the engine is only putting out a fraction of the power it could, so the control system shuts down half of the cylinders. Shutting off the injectors is easy (although the timing is critical) but shutting off the valves is a little more tricky. The 5.7L HEMI system utilizes a latching lifter, such that when the control system signals for a cylinder to become deactivated a solenoid opens and sends high pressure engine oil through a control gallery in the block that acts on a pin in the lifter to "un-latch" the lifter. Also packaged inside this special lifter is an extra spring called a lost motion spring, it's purpose is to keep the roller part of the lifter in contact with the cam and the push rod in place in the rocker arm.
The Cadillac V-8-6-4 system was similar but instead of a interrupting the motion at the lifter, the Cadillac system "un-latched" the rocker arm pivot point. The Cadillac system was electro-mechanical were the 5.7L HEMI MDS system is hydraulic - mechanical.
In any valve deactivation system you need three things, a way to break into the regular motion by latching / unlatching a mechanical element, a way to actuate this "latch", and some way to take up the lost motion in the system. There are many designs for overhead camshaft valvetrain configurations as well.

Answer 2

Engine control takes away oil from special push rods the valves don't open and fuel is shut off to those cyls. MDS chryslers name And chevy has a system too. Back in 1974 Cadilac Had a 4 six eight Cyl Eldorado. Seems to come back around everytime gas rationing or prices get high. The only problem is gasoline has to reheat those cooled parts. The emissions controls Cat converters have to be a little heavier to soak up the cold Cyl start and extra hydrocarbons.

Answer 3

An MDS is only available on a 5.7 L Hemi engine. What is actually does is when you are cruising at a constant speed the cylinders shut down from 8 to 4 so you are saving fuel. When the gas is pushed it goes back up to 8 cylinders to give the car more power.

Answer 4

Mds Solenoid

Answer 5

Lousy.Its a dumb idea, like the one cadillac used to ruin their reputation in the 70s.
The motor uses energy to move pistons that dont produce power.
It is better to use a small engine and add things like superchargers to produce more power.


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Answer 6

when additional power is needed the extra cylinders will work when power is not needed they will not get any fuel.