Recently I purchased a 2010 Lincoln MKT for my wife. This vehicle was a concept in 2008 and is the first model that is equipped with the 3.5L V6 twin turbo EcoBoost engine. With the purchase I've become interested in finding out what makes this engine tick. With the 2016 Ford GT making over 600 horsepower with the latest generation 3.5L V6, I've become very interested.
The 3.5L is comprised of old and new tricks from Ford. The injectors receive 65VDC of electrical push to overcome the 2200psi of fuel pressure on the top of them. At that fuel pressure the stock fuel injectors are effectively 157.5lbs/hr. The fuel pressure is generated by a two pump system - a low side and a high side. The low side is a returnless system feeding 65psi into the high side, and is modulated by an FPDM. The high side is a mechanical deadhead system driven off one of the engine cams. One full revolution of the camshaft produces four shots from the high pressure pump. At the end of the high side deadhead is an electronically linear sensor that reads the fuel pressure output at the rail. It hovers in the lower half of the hundreds of psi at idle, and can go north of 2200psi if instructed to do so. Burst pressure is at 3000psi, and is electronically noted in the PCM. Whenever you tap the Lincoln's key fob unlock button and see the lights go on, you hear a two second prime of the low side of the fuel system clearing vapor out of the fuel lines and ensuring a proper prime for the high side.
The EcoBoost engine is a speed density mill. There is no longer a MAF with this engine. In it's place, there are three pressure sensors. Two are on the engine, one is inside the PCM. There is a conventional MAP sensor, a BP sensor, and a TIP sensor. The BP is located inside of the PCM, with the MAP and TIP residing around the engine. While most are familiar with a MAP, TIP stands for "Throttle Inlet Pressure". There are many provisions within the EcoBoost PCM (referred as a Bosch TriCore by Ford) that are TIP based. Limits for overboost, limits for ramp rate, limits for hardware protection, etc. The boost is controlled much like fuel pressure is controlled in a EEC-V returnless fuel system. There is a feedforward table with corrective terms, with the end result centered around Desired Throttle Inlet Pressure. The PCM has a category titled "Turbocharger" with an extensive amounts of adjustments, with one subcategory titled "Boost Limit". Within the Boost Limit subcategory there are limits based upon actual and modeled variables, all free to be changed in the name of opening up additional power out of the 355hp engine.
For temperature sensors, the 3.5L gets an additional one in comparison to some of the forced induction Mustangs from years prior. There is a temperature sensor after the air filter (ACT), one at the throttle inlet (TCT), and one in the manifold (MCT).
The engine compression of the 3.5L is 10.0:1. Instead of a flat top piston, the block is stuffed with dome topped pistons with a recession in the middle. Fuel is sprayed into the middle of the dome, with oil injector nozzles spraying on the underside of the piston to aid in cooling.
The cams are VCT (variable cam timing). There is 29 degrees of total adjustment controlled from the PCM.
Like all late model Fords, the throttle is completely electronic. There is no throttle cable. The engine output is controlled in part by a Driver Demand table populated in Nm of torque, which expresses about 35.5% higher than the more widely-discusses ft/lbs. Layers of spark are present, although not as bad as the layers found in the Copperhead HDFX. Speaking of which, there is no weighting factor as a pointer as found with the HDFX layers.
---To Be Continued---
Edited by 03Steve, 06 February 2015 - 02:01 AM.