LATE-MODEL TECH ADVANCEMENTS - MOTOR

LATE-MODEL TECH ADVANCEMENTS

LateModel.indd 1 11/18/15 4:47 PM

19December 2015

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BY PAUL WEISSLER

Most of the new-car technology that you’ll even-tually be seeing on 2016 models is focused on

fuel economy, lowered emissions, customer satisfaction and delivery of appealing telematics. There often are interrelationships among the systems that deliver these features, although they aren’t always obvious.

Here are the areas domestic and import car manufacturers have put a lot of resources and effort into for 2016 and beyond, and the ones your shop will have to become adept at working on.

PrognosticsGeneral Motors has been making Wi-Fi an across-the-board telematics feature through its manufacturer-in-stalled OnStar system. We all know how telematics has appealed to the car-buying audience, but now GM is using the Wi-Fi availability to cre-ate the fi rst “prognostics” system in a passenger car line. Prognostics, as the name implies, comes from progno-sis, and with machinery it’s intended to predict how much remaining life there is in it. With airplanes, it has been used to predict maintenance re-quirements to prevent failure during fl ights. With 2016 Chevrolets, it will be predicting the life of the battery, starter and fuel pump with a sophis-ticated monitoring system focused on engine starting. So a motorist could get a warning that says, in effect, fuel pump performance has dropped to the point where you’ll start to experi-ence hard starting.

Prognostics potentially can go much further, also detecting worn brakes and tires, and the potential for overheating, transmission slippage, etc. It’s just a matter of time, and if the carmaker can detect vehicle prob-lems just prior to a service need, with high accuracy, independent shops will

Vehicle engineers focus a large percentage of their efforts on fuel economy, safety and emissions improvements. But automakers can and do continue to innovate in other areas of their vehicles as well.

LATE-MODEL TECH ADVANCEMENTS


20 December 2015

Late-Model Tech Advancements

be facing a new challenge to maintain market share. However, GM has said the nonwarranty service advisory will go to the motorist’s designated service provider, including independents.

What makes prognostics more sig-nifi cant than the “vehicle health re-port” carmakers use now is that prog-nostics is designed to detect short re-maining life before any conventional diagnostics or indicators, and before any trouble codes are logged. It uses algorithms and “hidden” calibration codes in some of the vehicle software to detect issues before they show up

as even a pending code. The exact methods are a trade secret, of course, but basically here are the general pa-rameters for the prognostics.

First, the vehicle needs a Wi-Fi connection so the system, which is connected to a GM cloud server, re-cords cranking voltage drop and ev-ery time-to-start, along with a reading from the battery temperature sensor as well as all the other on-car sensors, including ambient and coolant. So it also knows how much energy should be available for each idle-stop/restart. If the cloud server detects an unex-

pected deterioration, it can perform a more frequent monitor. And if the algorithm says the battery soon will produce a starting problem, it sends a notice to the motorist to bring the car in for battery replacement, free if within the warranty period. Further, if the battery is deemed good but the starter voltage drop is excessive, the system also will detect this, and will compare cold starting vs. warm en-gine restart, including after an idle-stop, to maintain an accurate assess-ment of the starter condition. The needed algorithms in some cases were developed for electric vehicles, which obviously need excellent assessments of battery and electric motor health.

Fuel pump performance is evalu-ated on the basis of excess pressure available—as every pump when new produces considerably more pressure than is needed. So if that margin is dropping off at a greater-than-expect-ed rate—even if well within specs for vehicle starting and operation—it will step up monitoring. And at some point, the algorithm will call for fuel pump, filter and circuit evaluation, with replacement if necessary.

Eventually, algorithms will use transmission hydraulic line pressures, shift solenoid operation times and dif-ferences between input and output speed sensors to maintain checks on the automatic transmission and detect excessive slippage. Sensors embed-ded in tires and brake linings (once used to trigger warning lights) will add prognostic coverage of these parts. At some future point, a motorist will be able to plug in a travel destination to his navigation system and get a prog-nostic evaluation for a trouble-free trip, or recommended service.

Prognostics has nothing to do with the Check Engine light, which illumi-nates according to regulatory require-ments. GM provides the prognostics free for fi ve years, but enables it only with the okay of the car buyer.

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GM prognostics monitors the battery, starter and fuel pump through a Wi-Fi connection that reports to a cloud server. Operation is monitored for signs of degradation.

This illustration depicts the sequence for early fault detection of a low battery and the message displayed on the instrument cluster. Unexpected failures should be reduced.


22 December 2015

New ArchitectureElectronic architectures based pri-marily on controller area network (CAN) are in universal use, but they aren't static. Fiat Chrysler’s PowerNet uses three primary bus-es—500kb/S CAN H for high-speed, 125kb/S medium-speed CAN-IHS for “interior” functions and 125kb/S CAN for telematics. The fi rst two use the body computer as the gateway; the last uses the radio module as the gateway to the CAN-IHS. In addi-tion, there are nine local interconnect networks (LINs), simple data transfer buses that operate at just 19.5kb/S.

Two things happened since Power-Net’s introduction in 2011. The fi rst is that new models are coming with even greater need for bandwidth. The second is that Fiat Chrysler is trying to install a worldwide architecture with even more flexibility. That led to Atlantis, which made its debut on the new Jeep Renegade, which is en-gineered here but manufactured in Italy. Another new Fiat product, the 500X small crossover, also has Atlantis.

This new architecture also uses the body computer as the gateway, but has two high-speed CANs. One is C1, which is primarily powertrain but al-so has connections that include ABS

and ORC (occupant restraints). The second is C2, which links chassis func-tions (such as electric power steer-ing) and has primary responsibility for safety systems (including the ABS and ORC that’s also on C1). Atlantis also has a medium-high speed called C-BH (for Body High) to link comfort systems and telematics, but which al-so covers the blind spot sensors.

There are four LINs connected to the body computer, plus others that are not, including the one for the keyless entry/ignition system. There’s also something called “Pri-vate CAN,” which is a 500kb/S bus for just the HALF (lane feedback signal) and DASM (driver assistance module for adaptive cruise control)—yes, just two modules are required to provide “private” communication for that safety-critical function.

U-Connect telematics, which were shown to be in danger of be-

ing hacked on PowerNet systems, are used on Atlantis. And although in a different configuration, all U-Con-nect telematics modules can com-municate with all other electronic modules on Atlantis. So with that po-tential exposed for PowerNet, one can hope this will not be a problem with Atlantis.

But stay tuned, because every carmaker’s system has some capa-bility to do things electronically that present opportunities for hackers. If GM’s OnStar can unlock doors and check all powertrain functions, that provides a similar entrance point for hackers. But we understand it still isn’t easy, and there’s general indus-try confi dence that the automobile is a much tougher nut to crack.

This new architecture gives en-gineering the flexibility to enhance safety system functions (including au-to braking), and by separating the

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An EGR valve and water cooler are new additions to the Pentastar 3.6L V6 for the 2016 model year. Possible plugging of the cooler with exhaust gas particulate matter makes it a potential maintenance item.


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In the variable lift system in the new Pentastar V6, solenoid valves control pressurized oil fl ow to lockpins in each intake valve roller follower assembly. When oil pressure is applied, the lockpin is moved against spring pressure, releasing the separately movable high lift follower (HLF), which pivots down, allowing the valve to operate on the low-lift cam for rpm up to 2800. When oil pressure is released, the pin springs back, and the follower pivots to operate the intake valve on the high-lift cam.

High-Lift Section of Follower (Separately Movable) High-Lift Mode: Cam on Base Circle

Position, Lockpin Is Engaged

Low-Lift Mode: Cam on Base Circle Position, Lockpin Is Disengaged

Low-Lift Mode: Low-Lift Cam at Max Lift, HLF Is at Its Max Lost Motion Position, Lockpin Is Disengaged

Intake Valve Follower

Bushing

High-Lift Mode: Cam on Base Circle Position, Lockpin Is Engaged

Mechanical lash is the clearance between the HLF and the lockpin on the cam base circle position.



high-speed CAN systems it should aid diagnosis. But it also creates a diagnostic issue: Right now the only in-terface between the scan tool and the underdash plug is the new microPod II; not even the VCI pod with a smart cable will work. At some point this will have to be sorted out to make the system compatible with SAE J2534 devices, but for the present you might just have to hold off.

An issue that applies to all of these new architectures is the prolifera-tion of modules with “what is this” naming. Not all of the acronyms even appear in the legends, and just be-cause you see a box on a diagram doesn’t mean it’s on the vehicle. With a “world” architecture, some may not be installed yet, may appear only on some vehicles sold here or may be installed only on vehicles not sold in the U.S. The OE systems will high-light on your PC screen what’s in-stalled, but you need a scan tool/diag-nostic system that does the same. An out-of-date unit or one with incom-plete coverage would support only certain modules, and if that doesn’t correspond with what’s on a particu-lar vehicle, it won’t be usable.

Water-Cooled EGRFiat Chrysler Automobiles is intro-ducing a water-cooled EGR system on its 3.6L Pentastar V6. Yes, we've seen this feature on diesels, but this is a new one for a domestic gasoline engine. Cooling the exhaust gases has established emissions control benefi ts (lowers NOx), but on Pentastar V6-equipped vehicles it also improves fuel economy, by .8% according to FCA engineering. This is the fi rst use of EGR of any type on the Pentastar, because the variable valve timing sys-tem had been calibrated to eliminate the need.

What’s useful to keep in mind is that this new EGR system is likely to be a signifi cant maintenance item,

because cooling the exhaust (from about 1200° to 265°F) causes parti-cles in the exhaust to drop out and restrict the tubing in the cooler. The restrictions may be just a coating that stabilizes and has a tolerable effect on heat transfer, or forms plugging

deposits. The coating occurs in high-gas-flow operation—mostly during highway use. The plugging occurs in operation that includes a lot of idling and light acceleration. Inas-much as most vehicles do some of both, EGR cooler plugging is like-

23December 2015

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reduces the efficiency of idle-stop. Although the statutory credit for cor-porate average fuel economy (CAFE)

24 December 2015

ly at some point. It would be possi-ble to mitigate the plugging with a thermal control of the flow path, so that only part of the cooler tubing is open when the flow rates are low, which would raise temperatures of the exhaust gas during that type of operation. Of course, the idea of the cooler is to cool the exhaust gas, so a balanced control would be neces-sary. When EGR coolers plug, there’s likely to be some engine knock, an emissions and perhaps fuel economy effect. We’ll have to see how diagnos-tic procedures sort this out, and how soon aftermarket suppliers develop cleaning systems for them.

Variable LiftVariable intake valve lift systems have been in use for many years, particu-larly on Honda products. The latest installation is part of the upgrading of the Chrysler Pentastar V6. The system has two computer-controlled solenoid oil flow valves per head—the front one for the front cylinder, the rear one for the second and third cyl-

inders, with oil flow channels to each of the intake roller followers. The system default is to high-lift mode, with a cam running on a movable section of the roller follower, and that high-lift section held in place by a spring-loaded lockpin.

During launch and low-speed ac-celeration, the solenoid valves open and pressurized oil pushes on the spring-loaded lockpins, releasing the movable high-lift sections of the roll-er followers. The high-lift sections pivot down and the followers run on the low-lift cams—up to 2800 rpm, during which torque peaks. Closing the solenoid valve and venting the oil pressure causes the pin to spring back, reengaging the follower and the high-lift setup.

Cold Storage EvaporatorsAs more vehicles get the engine idle-stop system, the issue of loss of air conditioning comes up. To date, the idle-stop has been disengaged when ambient temperatures are very high and the a/c is on. But this approach


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In this particular design shown by MAHLE (photo above left), a cold storage evaporator contains thermal wax-filled chambers or tubes in the headers and in the tubular area below. As refrigerant vapor flows through the evaporator, the thermal wax solidifies to pro-vide cold storage that absorbs heat from the airflow when the engine goes into an idle-stop. As shown in the illustration above right, with the engine stopped, airflow continues and a thermosyphon (TS) effect is set up in the evaporator core, which circulates refriger-ant vapor from the core tubng through the thermal wax area, cooling the airflow.

Refrigerant TS Effect

PCM Chamber

Air Out

AirIn

This illustration shows what a full disconnect AWD system looks like. The parts in blue do not spin when the system is running in front-wheel-drive mode; the only moving parts are those in red. Notice that the rear differential includes side gears, which are stationary.

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remains, the system may not deliver a measurable improvement in window sticker fuel economy. The problem could be “fi xed” with an electric drive compressor, as used on hybrids, but it’s a very expensive component, so the result has been a/c off when the engine shuts down.

To get around these issues, car-makers have started to install “cold storage evaporators,” and the new Honda Pilot and Acura MDX with the optional idle-stop are among the first so equipped. These are evap-orators with tubular sections filled with thermal wax, either built into the headers and/or installed between some of the tubular sections of the evaporator core. As the a/c operates, the refrigerant vapor flow through the evaporator causes the liquid wax in the tubular sections to solidify, for cold storage. When the engine and a/c stop, the blower fan keeps operat-

ing and airfl ow through the evapora-tor continues, where the air is chilled, not to the low temperatures of max a/c, but perhaps to the mid-50s. Transferring heat from the air via re-frigerant vapor circulation through the core to the thermal wax chambers causes the wax to liquefy.

At some point, the cold storage will be used up, the amount of time de-pending on the size of the wax sections and the air temperature, perhaps from 40 seconds up to more than 90 sec-onds. In most cases, the time will be long enough for the idle-stop. If it isn’t and the air temperature goes above some preset number while the vehicle is in an idle-stop, the engine will restart and the a/c will operate.

If the engine restarts and the vehi-cle runs for at least a few minutes, that would be enough time to recharge the cold storage. If the engine goes into another idle-stop before a full cold

recharge, the air chilling won’t last as long. Your customers may need an ex-planation of these limits.

If the evaporator ever needs re-placement, you’ll have to get one that includes the cold storage. An ordi-nary evaporator may fit but won’t provide the idle-stop cooling. How-ever, within a few years the after-market should be ready to market ones that will include cold storage, and meet SAE J2842 as well. This is the engineering performance stan-dard for evaporators that are used with R-1234yf, which is almost across the board on FCA products and will be phased in on many other vehicles starting next year.

All-Wheel DriveAll-wheel drive has gone mainstream, a system you’ll see on more and more passenger cars and crossovers, not just Subarus and SUVs like Jeep. But

26 December 2015


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This illustration shows how the rear differential in Honda/Acura vehicles works to distribute torque. A solenoid valve on the outside wheel closes to restrict oil fl ow, increasing torque to that wheel and allowing the vehicle to power through the turn.

Strainer

Pump Rotors

HighOil Flow for LubricationLow

Pressure Sensors

Linear Solenoid Orifi ceWide Open

Linear Solenoid Orifi ce Restricted

Acceleration-In-Turn


28 December 2015

with fuel economy such a high prior-ity, engineering efforts are focused on virtually eliminating the penalty of the AWD system. The approach is “full-disconnect”—that is, under light-load driving, the vehicle runs in front-drive mode and the AWD sys-tem comes on only when selected or when sensors indicate it’s needed.

There have been systems that didn’t connect the front transaxle with the rear differential unit, but there wasn’t a lot of power saved be-cause the rear axle shafts, differential gear assembly and in some cases even the propeller shaft all spun.

The front-drive mode for the Jeep Renegade uses an electric dog clutch in the front transaxle to separate it from the propshaft. In the rear an electric motor-controlled multidisc clutch can open to separate the axle shafts from the differential side gears, so although the axle shafts spin, they don’t have the drag of the differential gears. That’s virtually full-disconnect, and the Renegade is reportedly able to deliver 30 mpg highway fuel economy.

A new Honda/Acura Super-Han-dling AWD system features a far sim-pler, much lighter rear differential. The design used through 2014 has an

electromagnetic multidisc clutch pack with a two-step planetary gearset, with a mechanical oil pump. Although earlier systems had an acceleration device that provided a proportional increase in the speed of the outside

wheel to power it through a turn, the 2014 was a next-generation design that replaced that with a fixed-ratio setup that produced a 1.7% increase in outside wheel speed. For 2015, there’s a 2.7% fixed-ratio increase, which assists acceleration through turns tighter than 1.7%.

In addition, of course, the system has to transfer the needed percentage of extra torque to the outside wheel, and

the 2015 system eliminates the two electric clutch packs and the planetary gearsets. Instead, there’s an all-hy-draulic oil pump, although the flow is controlled by a solenoid valve to a sim-ple multidisc clutch pack for each side.

The pump maintains hydraulic pressure in the lines for fast response, but the solenoid valves are open, pro-viding a 50/50 torque split. When the vehicle is accelerating through a left turn, however, the right-side rear wheel is the outside wheel and needs more torque. The right-side solenoid valve closes as necessary, restricting its orifice, which builds up hydrau-lic pressure to apply the right-side clutch. This permits more torque to go to the right side (outside wheel) so it can power through the turn.

What makes this redesign important is that it maintains the maximum torque throughput of the differential, and re-duces its weight from 92 to 69 lbs.

New Air BagIf you thought the carmakers had run out of places to put air bags, Ford just found a new one, and for open-ers installed it on the 2015 Mustang. It’s a passenger-side knee air bag, built into the glovebox door. It’s not a conventional fabric design but an injection-molded plastic bladder in-stalled between the inner and outer panels. This design enables a much smaller inflator with no visible seams or air bag cover.

However, it means that if you’re doing underdash work on the passen-ger’s side, you have to be conscious of its presence and be sure to make the needed electrical disconnections properly if you have to completely re-move the glovebox. The operation of the glovebox air bag is integrated with the front air bag, so the passenger gets head-to-lower-leg protection.

This article can be found online at www.motormagazine.com.


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A new glovebox knee air bag is built into the cover and deploys to protect the passen-ger’s knees when the passenger’s side front air bag is activated.

You'll see AWD on more and more passenger cars and crossovers,

not just SUVs.


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LATE-MODEL TECH ADVANCEMENTS - MOTOR