same challenges, different solutions same challenges, different ...

Toyota Corolla LE ECO

SAME CHALLENGES, DIFFERENT SOLUTIONS

2014 IMPORT SERVICE OVERVIEW

BY PAUL WEISSLER

Like domestic manufacturers, import vehicle makers must improve fuel economy and meet strict emissions standards. Their solutions give buyers many choices, while keeping things interesting for service techs.

T

he import makes face the same fuel economy challenges as the domestic nameplates. They may feature smaller, more economical vehicles in their lineups, but that only means they have a tougher road to travel because they’ve already taken out a lot of the size factor.

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The Asian makes have pushed the hybrid button more often, but in 2014, one of the nonhybrid companies, Mazda, is ready to introduce a diesel. And hybrids do create a pricing issue, so the imports—particularly the Asians, who are more price-constrained than the Germans, with their luxury image—have to look at other choices, too.

Acura MDX

MAZDA3

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2014 IMPORT SERVICE OVERVIEW The big news in imports for 2014 comes out of the Toyota, Mazda and Acura camps. Let’s see what’s really going on there.

Toyota

The name Valvematic on the engine cover of a Toyota vehicle means it has the variable intake valve lift version of the 1.8L Four with variable intake and exhaust valve timing. The illustration below shows the actuator and shaft with individual cylinder intake valve lift mechanisms. The chart at the bottom shows a comparison of a Valvematic engine (2ZR-FAE) to the base engine (2ZR-FE). The intake valve lift for the Valvematic ranges from 1.1 to 11.5mm (.043 to .452 in.), compared with a single lift of 9.9mm (.39 in.) for a non-Valvematic engine.

Actuator

Variable Valvetrain Mechanism

Intake Camshaft

Intake Valve

2ZR-FAE

2ZR-FE

VVT

Intake Operation Angle . . . . . . 62° . . . . . . . . . . . 55° Exhaust Operation Angle . . . . 50° . . . . . . . . . . . 40°

Cam

Intake Operation Angle . . . . . . 106°-280° . . . . . . 246° Intake Lift . . . . . . . . . . . . . . . . . 1.1-11.5mm . . . . 9.9mm Intake Operation Angle . . . . . . 244° . . . . . . . . . . 234° Exhaust Lift . . . . . . . . . . . . . . . . 10.1mm . . . . . . . 9.7mm

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The new Corolla is a good example of an approach taken by Toyota—the CVT (continuously variable transmission) and its first U.S. application of variable intake valve lift. Toyota recognizes that hybridization does add more cost than the use of a conventional drivetrain. The CVT has certainly proved itself to be a fuel economy booster, and in the new Corolla, Toyota estimates it’s responsible for 3.5 mpg of the 42-mpg highway rating achieved in the Corolla ECO model. The CVT is a steel link belt type, much like those Nissan uses, although the transmission is Toyota’s own design. Like all CVTs, of course, Toyota’s requires a specific transmission oil—in this case a very low-viscosity oil to reduce parasitic losses. In addition, there’s a fluid warmer to improve efficiency during warm-up. The transmission is available on the ECO model and the top-of-theline S model, although the S version selects ratios for faster response. The fourspeed automatic continues to be available, but only on the low-end Corolla L. A six-speed manual, not likely to have a high take rate, will be the base gearbox on the L and an option on the S. The CVT has seven simulated shifts; that is, the transmission has seven ratios at which engine speed momentarily rises and falls. In addition, the S model has a “manual” shift mode, in which the driver can select those shift points. It’s all a game, as the CVT has no fixed gear ratio, unlike a conventional transmission. The base engine is the 1.8L Four with variable intake and exhaust valve timing, rated at 132 hp (unchanged from the previous model). However, the ECO 1.8, with its addition of the Valvematic variable valve lift system, is rated at 140 hp. The variable lift comes from an intermediate shaft with a mini gearset that pivots roller followers that rest against each cam lobe to vary the lift. A specific actuator controls the mechanism. If there’s ever a failure, the entire assembly must be replaced. The variable

2014 IMPORT SERVICE OVERVIEW

Alternator Generating Electricity

DC-to-DC Converter

Electric Components

Deceleration

Capacitor

The ultracapacitor and 12- to 25V alternator are keys to the i-ELOOP regenerative braking system introduced on the MAZDA6 and which is now on the MAZDA3, too. It saves the fuel used to power the alternator under low-speed operating conditions.

timing/variable lift is, like almost all others, a hydraulic system (oil pressure-controlled) with a specific actuator. Although new to the U.S. market, Valvematic has been used on Japanese market models since 2007. Much of the work done on the new Corolla was focused on improving body rigidity and creating a styling package that to date has not been a characteristic of a car noted primarily for reliability and simplicity. The 2014 model will have about 90% North American content at launch, with the CVT the primary imported part. That creates a supply issue for the intake valve lift system, which has been manufactured in Japan since its 2007 introduction, but now also is sourced in North America and reportedly is not easy to make. Therefore, for a time, there will be a limit to availability of the ECO model. The Corolla becomes the first car in the low-price class to feature LED headlamps. It’s said they’ll last indefinitely (eliminating a common maintenance item), but if they get damaged, we suspect the cost to replace them will be a shock.

Mazda

This 2.2L Mazda diesel, due to be introduced on the MAZDA6 next spring, is a low-compression design to permit operation without the need for the urea fluid (diesel exhaust treatment fluid) being used on other diesels.

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Among the most innovative of the import nameplates in the last few years has been Mazda, which, as a small manufacturer of primarily lower-priced cars, needs to select technologies that are extra cost-effective. For 2014 Mazda is introducing a novel “ultracapacitor” system called i-ELOOP in the MAZDA6, to save most of the fuel lost to alternator charging of the battery (10% of the fuel in city driving) by using an aggressive regenerative braking system. Normally, a regen system is intended to provide battery charging for an acceleration assist in a high-voltage (280V and up) or medium-voltage (110- to 140V) hybrid. But the MAZDA6 is a 12V car. Basic diagnosis is indicated when an “i-ELOOP Inspection Required” message is displayed on the dash and the master warning light goes on. This indicates that trouble codes have been logged and there’s a problem in one of the following: ultracapacitor, DC-to-DC converter, i-ELOOP harness or PCM. If there’s an obviously incorrect display

2014 IMPORT SERVICE OVERVIEW on the instrument cluster, that may also be at fault. The system features a 12- to 25V (varying voltage) alternator. As the vehicle slows, much of the energy of deceleration goes to operate the alternator, and the current produced goes into an ultracapacitor (also called a supercapacitor), which is sort of like a battery that can accept a charge and discharge quickly, too. That ultracapacitor, a 13.8-in.-high cylinder about 4.7 in. in diameter, is located underhood on the driver’s side. The charge goes through the DC-toDC converter to operate all electrical accessories; any surplus goes to charge the battery. The ultracapacitor can take a full gulp of electricity in 8 to 10 seconds and can discharge at a rate of as high as 50A at 14.5V in as little as 40 seconds. When the DC-to-DC converter is supplying all the needed electricity, the alternator just freewheels. The DC-to-DC converter has a maximum throughput of 50A at 14.5V, which surpasses the normal electrical load. HVAC, headlamps and other exterior lighting, audio system and wipers are about 40A. On a cold start, when the electric rear-window defogger is operating and there’s no regen braking or storage in the ultracapacitor, the alternator charges, of course. In fact, under those conditions it produces electricity at a higher rate than, say, 14.5V—in fact up to the maximum of 25V and 25A, an output that’s the most efficient for the system. If the electrical load during other operating conditions goes over the 50A limit, a relay closes and the system switches to conventional charging. The instant the load drops to 50A or below, the system switches back to regen and ultracapacitor operation. New diesel. Mazda’s forthcoming diesel is a 2.2L Four, but it’s different from the 2.2 oil burner that Mazda sells elsewhere. It’s all-aluminum, unlike the Chevy Cruze engine, and is one of the few that will not have urea injection. The reason: It’s a low-compression design (14:1), which is what reduces the reciprocating loads to enable use of the aluminum block. Although horsepower numbers haven’t been released, the engine is going to be rated at 310 ft.-lbs. of torque.

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The three-quarter front view of the body structure of the new Acura MDX shows the multiple beam system (in red). The side-view photo shows the yellow “ring” that integrates the A-pillar, B-pillar, roof and floor side member with the wheelhouse (in red). The interior view shows two red Y-shaped floor members—one into the side, one down the center—to help manage front crash energy.

Rear Heat (Floor) Duct

Right-Side 2nd Row Heat (Foot) Outlet Rear Vent (Face) Duct (2nd Row) Rear Heat (Floor) Duct (3rd Row)

Left-Side 2nd Row Heat (Foot) Outlet

2nd Row Center Heat Registers

The MDX underdash HVAC system uses a multiple-duct system to distribute heated or cooled air to the second- and third-row seats.

Vent Door

Heat and DEF Door Heater Core Partition Heater Core – Rear Zone

Air-Mix Door B – Front Zone

Air-Mix Door – Rear Zone

Heater Core – Front Zone

Mode Door – Rear Zone

Air-Mix Door A – Front Zone

Evaporator – Rear Zone

Evaporator – Front Zone

Evaporator Partition

Rear Blower

The layout of the underdash dual system of the MDX shows partitioned heater and evaporator cores and how the airflow is split. The system is shown in the maximum a/c cooling mode for the front and rear.

What Mazda has done with the lowcompression design is slow the ignition so there’s better fuel mixing and therefore more complete combustion. This reduces the soot and NOX that on highcompression diesels creates the requirement for urea injection. Low compression does have its disadvantages (it’s less efficient, for one thing), but the lighter weight apparently enables the engine to run at higher rpm to both spread out the torque band and increase horsepower. The diesel has a two-stage turbo (with small and large scrolls), which also contributes to good performance across the full rpm range, which will be at least 5200 rpm. The low-compression design would seem to affect engine starting, but Mazda is using new high-temperature ceramic glow plugs and piezoelectric injectors that can change the spray pattern for starting. Mazda also uses a variable valve lift system, but it’s for the exhaust valve, so it cracks open the exhaust valve during the intake stroke immediately after the engine starts. This pulls in exhaust gas, which raises the intake air temperature to improve the cold running. The diesel was due to reach the U.S. market late this year, but Mazda has put it off until next spring, as it’s still working on calibrations. We can’t say that’s surprising, because going without the urea solution injection and still meeting emissions standards is hard, apparently very hard. Because the engine isn’t available yet, we haven’t got a lot of technical details, particularly on the exhaust valve lift system. The MAZDA3 also is a new model, incorporating the Skyactiv technologies previously introduced on the last edition and including the i-ELOOP regenerative braking that made its debut on the MAZDA6. Highway fuel economy will be 40 mpg for the hatchbacks (manual or automatic) and 41 mpg for the sedans. The 2.0L Four rated at 155 hp is the standard engine, although the 2.5L Four rated at 184 hp is available on sport models.

Acura The new Acura MDX was completely redesigned for the new model year. Like other new Honda division mod-

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2014 IMPORT SERVICE OVERVIEW els, it has a body designed to pass the small offset crash test just instituted by the Insurance Institute for Highway Safety. This test is intended to simulate a crash into a narrow solid barrier, such as a telephone pole, so a lot of added structure is necessary. Honda has a safety engineering system called

“ACE” (advanced compatibility engineering) for this sort of thing, but the MDX is a large, heavier vehicle, so it’s a greater challenge. If you look at what was done, you’ll see a lot of front-end braces through the underbody and a “ring” that combines the A- and B-pillars, roof and side rails to distribute

crash energy. This is likely to create some service issues for underbody access, as well as add complication for front-end repair. HVAC. The MDX dashboard also holds a first-ever design of its type— separate front and rear HVAC systems. It’s two systems in a single housing, not just one system with extra ducting to the rear. Acura claims performance equal to a design with a separate rear unit. The underdash housing is a physically larger system than one where there’s that separate rear unit. The internal airflow passages are somewhat complex, but the whole thing is configured so the airflow is equal to the need. The evaporator and heater cores not only are larger (by about 30%) than those for single systems, but are partitioned for front and

FRONT

The inboard side of the dashboard cover substrate forms one of the rectangular surfaces of the HVAC ductwork, a spacesaving feature in the dual HVAC design.

rear HVAC, and there’s a second blower motor at the front system, too. The airflow split is about 65% front, 35% rear. Combined with the increased frontend bracing and the usual cross-dash bracing for side-impact protection, the new HVAC likely will make other underdash service, not just the HVAC, a greater challenge. Furthermore, the diagnosis could become more difficult if such factors like debris become part Circle #18

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of the picture for both sections. So if the exterior ductwork is intact, most of any service issues—with a couple of noteworthy exceptions—are likely to be in that complex underdash unit. The exceptions are: •The integration of the front heated/cooled seats into the climate control strategy, for improved fuel efficiency. There will have to be some way for a technician to know if a drop in a/c performance is a computer decision to use the seat cooling to compensate for a strategy-ordered dashboard output or a malfunctioning a/c system. •A second-row control panel, which covers temperature, airflow (from the second blower motor) and airflow directional pattern. There’s one additional space-saving aspect of the design: The inboard side of the dashboard

what was obtained in the previous model with its separate rear system, Acura had to create a really unusual HVAC case for air blending and an unusual ducting system to the second and third rows. The a/c cooling is from an underconsole duct to the second row that terminates at the HVAC control

panel and outlets. The system results in a 50-gram (2-oz.) reduction in refrigerant capacity to 700 grams, and far fewer refrigerant line connections for greater reliability. There’s a floor duct on each side for second-row heating and a third-row heating duct under the second-row a/c duct.

C-Channel Duct IR-Welded to Substrate

BACK substrate is shaped to provide a closing side to the ductwork. Underdash, it would seem that an oversize evaporator—which is canted to fit into what is a tight package—would be prone to trapping a lot of condensate in the HVAC case. However, the HVAC engineers said the canting setup was part of the engineering for good evaporator drainage, and have patents on the work done to ensure this. To provide the claimed performance for the second and third rows equal to This article can be found online at www.motormagazine.com. Circle #19

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