Direct-Injection Explained: DI uses a fuel injector inside the combustion chamber just as with a diesel engine. Changing the point of injection from the intake port - the norm in most fuel-injected engines today - to the combustion chamber produces significant advantages. Foremost is increased gas mileage, resulting from super-efficient atomization of fuel accomplished by injecting it at very high pressures. Better atomization produces more complete combustion of the fuel, therefore using fuel more efficiently. In addition, direct injection's more precise fuel metering results in more precise control of engine rpm, for better engine response. The result is a lowering of the idling rpm (from 750 to 600) and an expansion of the fuel cut-off area when coasting. Both help save gas as well.
These aspects of the DI system allow the engine to operate very close to stoichiometric combustion. Stoichiometry is the branch of chemistry that deals with the laws of definite proportions - in this case, the proportions of air and fuel necessary for complete combustion. In a stoichiometric combustion event, the air-to-fuel ratio is optimal so that the fuel is burned completely, along with all the carbon, hydrogen, and sulfur within the fuel. This is what allows the Isuzu DI engine to meet emissions standards in this country and to offer better fuel economy. The EPA rating for the '04 Axiom 2WD with direct injection is 18 mpg city and 23 mpg highway - gains of 6 and 10 percent respectively compared with the previous port-injected 3.5L V-6.
The second advantage comes from DI's cooling effect. Spraying fuel directly into the combustion chamber allows the fuel to vaporize there as opposed to in the intake port. Vaporizing fuel actually reduces combustion chamber heat. This, in turn, allows Isuzu engineers to use a much higher compression ratio (10.3:1 versus the conventional engine's 9.1:1) without risking pre-detonation or engine knock. Higher compression produces more power - 250 hp in the DI V-6 versus 230 hp in the non-DI engine, an 8.7 percent gain. Torque also increases, going from 230 lb-ft to 246 lb-ft, a gain of 7 percent.
The increased power produces, according to Isuzu, a 0-60 time of 7.5 seconds in the Axiom DI, versus 8.9 seconds for the non-DI powerplant, and a quarter-mile acceleration time of 15.8 seconds, versus 16.5 for the non-DI motor.
In addition to the performance gains, Isuzu reports that the reduction in tailpipe emissions bumps the '04 Axiom from the EPA's "LEV" category to "LEV2," further validation of the direct-injection technology.
Firestone to Be Inducted Into Cruisin' Hall of FameIn recognition of the many contributions it has made to the automobile industry during the last 100 years, the Firestone brand was inducted into the Cruisin' Hall of Fame at the 14th Annual Stater Bros. Route 66 Rendezvous.
Firestone's storied history stems back to 1900 when Harvey S. Firestone founded The Firestone Tire & Rubber Company in Akron, Ohio. At a time when the world was moving from the horse and buggy to the automobile, Harvey Firestone was a visionary who helped mold the transportation industry and the country's history. Making tires for everything from shipping trucks to race cars, the former Firestone Tire & Rubber Company and its successor companies' 103-year-old involvement with the transportation and racing industries has been one of countless milestones and achievements.
Harvey Firestone also broke ground in the nation's transportation movement, supporting the creation of the first coast-to-coast highway and advocating an interstate highway system, which helped build famous highways, such as Route 66. In addition, he created the "Ship by Truck" campaign, encouraging manufacturers to move their products to markets by truck. In fact, the very first coast-to-coast truck shipment of goods traveled across the country on Firestone tires.
The Cruisin' Hall of Fame was established in 1995 by the San Bernardino Convention & Visitors Bureau, in conjunction with the City of San Bernardino, to honor those who have made a significant contribution to the uniquely American automotive cultural phenomenon of cruising. In addition to Firestone's induction, the Cruisin' Hall of Fame also honored Parnelli Jones, Route 66 magazine, and the Specialty Equipment Market Association.