15 What does SOHC, SMPI, etc mean? What do I have?
Description
This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
15 What does SOHC, SMPI, etc mean? What do I have?
Note: No current Chrysler has a distributor or throttle body injection.
* DIS means distributorless ignition system. No rotor!
- Chrysler is moving past DIS to a coil-on-plug system
* SOHC and DOHC refer to the number of camshafts; one or two.
* EFI means electronic fuel injection, such as the following:
* TBI - throttle body injection; one or two injectors
spray fuel into the air as it heads to the cylinders.
* MPI uses one fuel injector for each cylinder. It sprays fuel in the
intake manifold, firing at the intake valves. These are smoother than
TBI systems, and have more power *and* better mileage.
* SMPI is sequential multiple-point injection; the injector only
fires when the fuel can go straight through the valve and into
the cylinder instead of splashing onto a closed valve.
* Direct injection sprays fuel directly into each cylinder.
This is mainly used in Diesel engines (thanks, Michael Turley!)
Note: all current Chrysler products use DIS and returnless
SMPI. Mitsubishi is pioneering direct injection for gas engines.
Continue to:
My Books
