Cold and hot heart, GM L3B engine
The engine of a car has two opposing properties. One is ‘cold’ and the other is ‘hot. The reason for these two contradictory properties is that they are made of ‘metal’. Since the history of engines that began with steam engines, mankind has always made engines out of metal. Recently, due to the development of material mechanics, attempts have been made to use synthetic materials other than metals, but the mainstream of all engines on Earth is still metal. Metal such as steel and aluminum can handle all the burdens such as high heat and friction that occur from the time the engine wakes up throughout the operating time, and is also suitable for mass production.
We invite you to the world of engines, the heart of a cold and hot car made of metal. The fifty-seventh engine of many automobiles covered in this article is GM’s downsizing gasoline engine, GM L3B engine.
The backbone of GM cylinder set strategy
GM’s L3B engine is the latest engine that was first unveiled in 2019. The GM L3B engine goes beyond the trend of downsizing, which has become a trend around the world, and is tailored to the tone of “Rightsizing” that GM claims. This engine was developed based on the ‘Cylinder Set Strategy (hereinafter referred to as CSS)’ currently being developed by GM, and has a unique configuration in many ways. The new four-cylinder engine is gaining popularity in the U.S. auto market as an engine that will be applied to GM’s next-generation product line in the future.
The CSS, which GM refers to, is to develop five cylinders that are optimally designed and create various variations based on them. The five cylinders also share the functional parts of the engine. The cylinders developed through the optimization process are arranged in a layout such as three cylinders, four cylinders, and six cylinders as necessary. And the main of these is a four-cylinder engine like the L3B. Of course, direct injection and turbochargers are used for all engines to achieve the best performance and efficiency in reduced emissions. Another engine developed under this strategy is the 1.35-liter three-cylinder turbo engine currently applied to Chevrolet Malibu and Trail Blazers.
The L3B engine is a structure in which four large cylinders, with a cylinder bore (internal diameter) of 92.25 mm and a piston stroke (stroke length) of 102 mm, are arranged in series, and has a total displacement of more than 2.5 liters, which is rare for a four-cylinder engine. The L3B engine has a total displacement of 2.7 liters (2,727cc), which is generally considered to be equivalent to a six-cylinder engine. Engines with a displacement of more than 2.5 liters are mainly diesel engines used in commercial vehicles, but this engine is more unique because it is a gasoline engine used in both passenger and commercial vehicles.
The L3B engine uses aluminum for both the cylinder head and the block for lightening. The cylinder head is made of 356 T5 cast aluminum alloy and the cylinder block is made of 380 T5 cast aluminum alloy. In the case of the valve train, the DOHC method with four valves per cylinder is employed, and both the variable valve timing mechanism (VVT) and the variable valve lift (VVL) are employed. The compression ratio is 10.0:1, and the direct injection method (GDI) is used for fuel supply.
The L3B engine uses a turbocharger as its base, not a natural intake method. The turbocharger in use uses a single turbocharger supplied by BorgWarner. This turbocharger is a dual-volute turbocharger that the company first unveiled in 2018, and features a unique internal structure.The dual-volute turbocharger has a basic structure similar to that of a twin scroll turbocharger. Twin Scroll Turbo is a turbocharger with two “scrolls” applied to one turbine, which corresponds to the path through which exhaust gas passes.
Twin scroll turbos have the same standard of scrolls divided into these two. In addition, the two scrolls are separated through the partition wall, but not completely separated. On the other hand, the dual-volute turbocharger is divided into two scrolls asymmetrically. The two scrolls are divided into large and small scrolls, respectively. In addition, the two scrolls are completely separated. Thanks to this, further improved efficiency may be expected compared to a conventional twin-scroll turbocharger.
BorgWarner, who developed the turbocharger, says the structure has made it possible to use the energy of the exhaust gas more efficient. This turbocharger was originally developed and used first to apply to diesel engines for commercial vehicles, but Vogue Warner began research in 2012 to apply this method to gasoline engines and completed it in 2018. It also uses a wastegate operated by an electronic actuator. The GM L3B engine, which has been completed in this way, has a maximum output of 310 horsepower or more and a maximum torque of 48.1 kg.m or more, depending on specifications.
The first type of vehicle to which the GM L3B engine was applied is none other than a “pick-up truck.” This engine is also applied to “Silverado,” a full-size pickup, not a Chevrolet Colorado-class mid-sized pickup. In general, a full-size pickup truck in the United States uses a V6 engine with a displacement of well over 3 liters for strong low-speed torque, and the most popular engine is a V8 engine with a displacement of 5 liters or more.
For this reason, it is quite unusual to apply a four-cylinder engine to a full-size pickup truck. The L3B engine applied to Silverado has a maximum output of 355 horsepower/5,600 rpm and a maximum torque of 52.9 kg/4,100 rpm. This can be seen as a level of performance corresponding to the V8 engine of the natural intake OHV method used in the past.
The GM L3B engine applies not only to Silverado, but also to Cadillac, a luxury brand. It is the recently announced sports sedan of Cadillac, CT4. The L3B engine installed in the CT4 is divided into two main types: a specification applied to premium luxury, a high-end trim, and a specification applied to CT4-V, a high-performance trim. The engine applied to the CT4 premium luxury trim has a maximum output of 310 horsepower/5,600 rpm and a maximum torque of 48.7 kg/1,800 rpm. 토토사이트
For engines applied to CT4-V, it exhibits a maximum output of 325 horsepower / 5,600 rpm and a maximum torque of 52.5 kg.m / 1,800 rpm. Cadillac calls the engine “Torque Monster.” In particular, thanks to the strong torque emitted from 1,800 rpm, it is expected to have a stronger acceleration than before.