2010 GM 3.5L V-6 (LZ4, LZE)
3.5L V-6 (LZ4, LZE) CAR ENGINE
2010 Model Year Summary
E85 Flex Fuel ( LZE ) engine added to Malibu for 2009 model year interim
New split converter systems for OBD2 compliance on LZE Impala with NW Bin 4 emissions
Expanded usage of E37 ECM on Impala, and Malibu
High mileage dependability improvements-mist quench cylinder heads, PQ5 coated cylinder head gaskets, Brico 3010 exhaust valve seats and FKM coolant crossover gasket,
Full Description of New and Update Features
GM’s new-generation 60-degree 3.5L V-6 is available for 2010 in the Chevrolet Malibu, and Chevrolet Impala. It is installed with the Hydra-matic 4T45 four-speed automatic in the Malibu, and the 4T65 four-speed automatic in the Impala.
E38 Engine Control Module
An advanced controller manages the multitude of operations that occur within the 3.5L V-6 every split second. The E38 is the mid-line controller in a new family of engine control modules (ECM), which will direct nearly all the engines in GM’s line-up. In combination with advanced sensor technology, the E38 includes the ability to control and synchronize advanced technologies such as cam-in-block variable valve timing.
The E38 features 32-bit processing, compared to the conventional 16-bit processing in previous 60-degree V-6 engines. The E38 operates at 59 MHz, with 32 megabytes of flash memory, 128 kilobytes of RAM and a high-speed CAN bus, and it synchronizes more than 100 functions, from spark timing to cruise control operation to traction control calculations. The E38 works roughly 50 times faster than the first computers used on internal combustion engines in the late 1970s, which managed five or six functions.
The family strategy behind GM’s new ECMs allows engineers to apply standard manufacturing and service procedures to all powertrains and quickly upgrade certain engine technologies, while leaving others alone. It creates both assembly and procurement efficiencies, as well as volume sourcing. In short, it creates a solid, flexible, efficient engine-control foundation, allowing engineers to focus on innovations and get them to market more quickly. The family of controllers means the ECM and corresponding connectors can be packaged and mounted identically in virtually every GM vehicle. GM creates all the software for the three ECMs, which share a common language and hardware interface that’s tailored to each vehicle.
The E38 also applies a new, rate-based monitoring protocol sometimes known as run-at-rate diagnostics. Rate-based diagnostics improve the robustness of the Onboard Diagnostics System (OBD II) and ensure optimal performance of emissions control systems. The new software increases the frequency at which the ECM checks various 3.5L V-6 systems, particularly emissions-control systems such as the catalytic converter and oxygen sensors. Rate-based diagnostics more reliably monitor real-word operation of these systems and allow regulatory agencies to more easily measure and certify emissions compliance.
E85 Flex Fuel engine (LZE)
GM has led the industry in introducing flex-fuel capability to its cars and trucks, and the flex-fuel 3.5L V-6 (RPO LZE) extends availability to an even broader range of customers. E85 is a clean-burning alternative fuel made in the United States from corn and other crops, composed of 85 percent ethanol alcohol and 15 percent gasoline. The 3.5L V-6’s flex-fuel technology is both sophisticated and durable.
The first flex-fuel engines required special valves and valve seats to withstand the corrosive effects of ethanol. Not the 3.5L V-6. The Silcrome 1 valves used in all variants are up to the challenge. Compared to conventional iron-alloy valve material, Silcrome 1 includes tungsten, vanadium, manganese, silicone and higher chromium content. It is harder, and it improves durability, even under the rigors of ethanol operation.
Hardware changes for flex-fuel operation are limited to the injectors. Because ethanol has fewer BTUs (less energy) than the same volume of gasoline, more fuel is required to produce the same horsepower at wide-open throttle. Flex fuel engines use unique stainless injectors with a greater cone angle and higher maximum fuel-flow rate.
The flex-fuel 3.5L V-6 does not require a special fuel sensor. The first flex-fuel engines used a light-reactive sensor to measure fuel composition from 100 percent gasoline to 85 percent ethanol. The 3.5L V-6 has a virtual sensor—software programmed in the E38 ECM with no separate physical sensor. Based on readings from the oxygen (O²) sensors, fuel level sensor and vehicle speed sensors, the ECM adjusts the length of time the fuel injectors open for the type of fuel used. Within a few miles after filling up, the E38 controller determines what fuel is powering the 3.5L V-6 and manages the engine accordingly.
E85 fuel provides an environmentally friendly companion or alternative to gasoline. It is biodegradable and doesn’t contaminate the water supply. Ethanol can be produced from various feed stocks, including corn and wheat stalks, forestry and agricultural waste, and even municipal waste.
PZEV Emissions Certification
The 3.5L V-6 (LZ4) engines built for vehicles sold in California and the Northeast states meet PZEV tailpipe and evaporative emissions standard. They are equipped with a three-point single-bank or six-point dual-bank air injection reaction (AIR) system. AIR lowers HC and CO levels by injecting warm, fresh air into the exhaust manifold to create an exothermic reaction that combusts fuel residue. With improvements to manifold and other intake sealing gaskets, the 3.5L V-6 generates essentially zero evaporative emissions.
Overview
GM’s new overhead-valve V-6 engines define the concept of high value in powertrain development. They apply and refine time-tested design principles, yet they are new from the cylinder block up. The deliver advanced, industry exclusive technologies with real benefit for customers, yet they keep both the cost of production and the cost of ownership low. By any measure, the 3.5L V-6 delivers a top-notch balance of good specific output, low-end response, even torque delivery, low maintenance and value, with vehicle packaging flexibility in a wide range of applications.
This new generation V-6 allows a high level of flexibility, with common castings over a range of displacements. The 3.5L V-6 shares its block, pistons and cylinder heads with GM’s 3.9L (RPOs LGD and LZ9). The common bore measures 99 mm and displacement is increased in the 3.9L with a longer stroke (84 mm vs. 76 mm for the 3.5L). The two engines share 80 percent of their parts.
Thanks to its relatively narrow 60-degree block angle, the 3.5L V-6 is compact, giving vehicles teams more latitude with platform design and styling. More importantly, the 60-degree V-6 is inherently balanced, ensuring powertrain smoothness without the additional cost of balance shafts. The new 3.5L V-6 differs from previous GM 60-degree designs in its offset cylinder bores. The centerlines through the bores on each bank do not intersect at the crank axis; rather, they intersect 3 mm below the crank axis. The offset bores present a number of advantages, including room for larger cam journals and flexibility to stroke the engine for more displacement. The 3.5L block also features a unique “U-flow” coolant path. The coolant passages flow coolant in a specific, predetermined path, starting at the front of block, then rearward toward the transmission, up through the cylinder heads and back to the front. The thermostat is placed near the inlet from the radiator, decreasing warm-up time. The fill point is at the highest point of the cooling system to prevent air pockets in the hoses or passages.
New cylinder heads apply design features developed for the high-output LS1 and LS6 Corvette small-block V8s. The 3.5L V-6’s valves are similar to those in the LS1, as is its combustion chamber design. Low-friction hydraulic roller lifters work the valves, improving the engine’s efficiency and reducing vibration. The 3.5L V-6 also applies the latest electronic throttle control (ETC) technology, streamlining the system by eliminating a separate throttle actuator control (TAC) module. The ECM controls the throttle motor directly. The direct link improves throttle response time and improves system security by removing a device (the TAC) the must be monitored for malfunction.
The 3.5L V-6’s “returnless” fuel injection system is the new standard at GM. It eliminates fuel return lines between the engine and the gasoline tank, essentially eliminating heat transfer from the engine to the fuel tank and thus reducing the amount of vapor emissions. New generation fuel injectors with shrouded nozzles are designed to minimize clogging and maintain optimal performance in extreme heat. The 3.5L V-6’s flex-fuel technology (LZE) is simpler and more robust than that used on previous flex-fuel engines. The standard valves and valve seats are durable enough to withstand the long-term corrosive effect of E85 ethanol, so no upgrade is necessary. Nor do flex-fuel 3.5L V-6’s require a separate fuel sensor. The advanced E38 ECM uses data from the oxygen sensors to determine fuel composition, and within miles of a fill up adjusts fuel and spark timing for optimal performance with whatever fuel is used.
For all the advanced systems in the 3.5L V-6, perhaps the most significant—certainly the one that has garnered the most attention—is variable valve timing (VVT). GM’s new generation V-6s were the first cam-in-block engines with VVT—an accomplishment engineers considered extremely difficult, if not impossible, just a few years ago. The 3.5L V-6’s dual-equal VVT uses a hydraulically operated vane-type cam phaser that turns the camshaft relative to its drive sprocket.
The advantages of cam-in-block VVT are pronounced. The cam phaser changes valve timing on the fly, maximizing engine performance for given demands and conditions. At idle, for example, the cam is at the full advanced position. That allows exceptionally smooth idling. Under other operating demands, the phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm it might retard timing to maximize airflow through the engine and increase horsepower. At low rpm it advances timing to increase torque. Under a light load (say, casual everyday driving), it can retard timing at all engine speeds to improve fuel economy. Without cam phasing, a cam design must be biased toward one strength or another—high-end horsepower or low-end torque, for example—or profiled at some median level that maximizes neither.
Variable valve timing allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or drivability. It also provides another effective tool for controlling exhaust emissions. Because it manages valve overlap at optimum levels, it eliminates the need for an Exhaust Gas Recirculation (EGR) system.
Virtually every component and system in GM’s new generation cam-in-block V-6s was reviewed in an effort to enhance durability and reduce noise, vibration and harshness. Piston-cooling jets remain the exception rather than the rule in overhead cam engines, yet each piston in the 3.5L V-6 has its own pressure-actuated jet that sprays oil toward its skirt, coating its underside and the cylinder wall with an additional layer of lubricant. The extra lubrication cools the pistons, reducing both friction and operational noise and helping ensure durability. The cam-drive chain has a leaf spring-type dampener that maintains optimal chain tension for the life of the engine and eliminates any flapping motion that might develop as the chain stretches with mileage. It ensures that the timing chain operates as smoothly and quietly as new, even as the engine accumulates high mileage.
Multi-layer steel gaskets are sandwiched between the block and cylinder heads to maintain optimal sealing for the life of the engine. The cast-iron exhaust manifolds are fitted with heat shields fabricated from stainless steel and insulating material. These limit heat transfer from the engine to the engine bay, allowing the 3.5L V-6 to reach optimal operating temperature more quickly, yet reducing heat in the engine compartment once that temperature is achieved. They also dampen the sound of exhaust gas rushing through the manifolds and further reduce the amount of engine operational noise that finds its way into the vehicle interior. A cast aluminum oil pan increases engine rigidity and radiates less noise than a conventional steel pan. An acoustic engine cover further reduces the amount of noise transmitted to the passenger compartment from the engine.
Low maintenance was a development priority. The spark plugs have an iridium tip and core to maintain spark density over their 100,000-mile life, helping ensure the same fuel efficiency and emissions performance over the last 10,000 miles as the first. The coolant and accessory belt are both expected to last 150,000 miles. Maintenance in typical use is limited to oil changes, and even those are made as simple as possible. The GM Oil Life System measures how hard the engine is used and calculates the optimal life expectancy of the engine oil, indicating an oil change when it’s actually needed, rather than according to some predetermined mileage schedule.
With its new generation of 60-degree overhead valve engines, GM has once again demonstrated that the inherent advantages of cam-in-block technology can be applied in the environmentally sensitive 21rst century, in trucks and cars. The 3.5L V-6 brings innovation to the mainstream, with wide application in a high-value package the typical consumer can afford.
