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Aug 2, 2007




According to a recent article, when Toyota Motor Corp. introduced its 3.5L, DOHC V6, 2GR-FSE, many eyebrows were raised. The reason? The engine would be the first to combine direct-injection gasoline (DIG) fueling with conventional port fuel injection (PFI). The engine was launched in the 2006 Lexus IS 350, and has won two consecutive Ward’s 10 Best Engines awards.

Toyota indicated that the engine was developed in order to increase performance while at the same time reducing emissions. Now, others in the industry are “migrating to DIG fueling as a way to improve performance and fuel consumption” according to the article. Using direct injection alone forced Toyota to make certain compromises when developing engine technologies, for DIG used alone tends to limit volumetric efficiency and wide-open throttle engine performance. When combined with port fuel injection, an engine with DIG fueling would not experience curbed volumetric efficiency or high levels of cold-start emissions.

Toyota’s twin-injection design is called D-4S, a variation of the D-4 architecture which has been used since 1996 for four-cylinder engines and is now used in the inline 6 and V6 engine families. The D-4S delivers fuel in a “more evenly distributed spray pattern in the cylinder, precluding the need for high levels of charge motion,” according to the article. There is a DI injector and a port injector for each of the engine’s six cylinders. Toyota engineers say that brake-specific fuel consumption is improved by 4% and start-up emissions are reduced by 20%. The PFI system typically operates on its own during the actual cranking part of the engine startup phase. It is during this time that a substantial portion of the “raw” emissions of a cold start are produced. During high-load operation, only the DI injectors are used, which maximizes the DI’s ability to deliver a cooler and denser air/fuel mix. This promotes maximum power and torque.

As these types of technologies are further developed and improved upon, we should expect to see more of them in a wider range of vehicles, not just the premium brands. Automakers are continually finding ways to make more power and torque while at the same time creating engines that are more fuel efficient.

Source: Visnic, Bill. (July 23, 2007). “Toyota V6 Twice-Injected With Innovative Thinking.” Retrieved July 23, 2007 from

1 comment:

Anonymous said...

Hi, ¿what are you think en definitiva about this tecnolgy of dual injection?

Toyota Motor Corp.: 3.5L DOHC V-6
By Ward’s Staff, Dec 19, 2008 8:55

Special Report
Ward’s 10 Best Engines

Laying claim to its fourth-consecutive slot on the Ward’s 10 Best Engines roster, Toyota Motor Corp.’s 3.5L Lexus V-6 once again emerges as the engine to beat among a field of excellent V-6 competitors.

With a delectable balance of power, grace and technology, the engine powering the Lexus IS 350 is a favorite of several judges and impresses all with its class-leading horsepower, torque and fuel economy.

Not much can be said about this engine without directing attention to its unique fuel-injection system, comprised of separate port- and direct-gasoline-injection circuits.

>>>>>>>¿Esto me parece cursioso, por fin que opinas de la tecnologia de inyeccion Dual?<<<<<<
Criticized by some judges as an over-engineered, “belt-and-suspenders” approach, the dual-stage fuel system improves all-around performance by taking advantage of the strengths of each technology.
Nissan Motor Co. Ltd.’s larger VQ 3.7L DOHC V-6, for example, easily trumps the Lexus in top-end power without DIG, yet trails it in terms of torque output and observed fuel economy.

Even Honda Motor Co. Ltd.’s 3.5L SOHC V-6 and General Motors Corp.’s 3.6L DOHC V-6, both of which make a return to 10 Best Engines status, lag the Toyota mill in overall flexibility and outright power delivery.

However, unlike the GM V-6, which frugally burns regular unleaded, the Lexus’ high 11.8:1 compression ratio necessitates the use of premium fuel. And for all its DIG-infused torque, horsepower peaks at a relatively high 6,400 rpm.

Fortunately, the engine loves to rev to its redline and feels honed to near perfection in the process.

As noted last year, Toyota is making baby-step headway in infusing its products with a more-passionate connection to the driver. We find this Lexus variant of the Toyota 3.5L DOHC V-6 to be one of the best examples of that focus, particularly with the sweet-sounding optional sport exhaust.

Yet, not all are enamored by the melodies emanating from the car’s twin oversized tailpipes. While some judges favor the mechanically precise wail at full throttle, others find it to be droning and too loud at low speeds.

Regardless, this engine portends the auto maker’s eventual shift to DIG engines and provides its Lexus brand with a shot of vigor that is missing from other Toyota vehicles.

Although two impressive V-8s made this year’s list, high-output 6-cyls. such as this make it clear that a solid V-6 will continue to grow in importance as the keystone in many premium-powertrain game plans.

Congrutalations, a good post, a link extra about the engine: