Because diesel engines operate and emit exhaust differently from gasoline engines, many new technical terms are introduced when discussing diesel vehicles. For example, models like the Jetta SDI and Bora 1.9 TDI reflect these advancements. These names often indicate specific technologies used in the engine design.
SDI stands for "Spark Ignition Direct Injection" – no, actually, it's "Straight Diesel Injection" or more accurately, "Single-Direction Injection." It refers to a naturally aspirated direct injection diesel engine that uses Bosch’s electronic control fuel distribution pump. An example is the FAW-Volkswagen Jetta 1.9GDF, which features a 1.9-liter SDI engine with a compression ratio of 19.00. This engine meets Euro III emission standards and delivers a fuel efficiency of 4.6 km per liter at 90 km/h. In real-world use, drivers typically consume less than 5.5 liters per 100 km.
TDI stands for "Turbocharged Direct Injection," which builds upon SDI by adding a turbocharger. It also utilizes Bosch’s pump nozzle technology, allowing for an injection pressure of up to 1870 bar. The FAW-Volkswagen Polaris 1.9 TDI engine, for instance, has a similar compression ratio of 19.00 but includes a variable vane turbocharger that can adjust boost pressure at any speed, significantly improving performance over traditional turbochargers. It meets Euro III emissions and consumes about 5.5 liters per 100 km at a constant speed of 90 km/h, though actual consumption may be slightly higher, around 6.3 liters per 100 km.
Pump nozzle injection increases the injection pressure, leading to a more complete combustion of the air-fuel mixture. Combined with an oxidation-type catalytic converter, this reduces carbon monoxide and nitrogen oxide emissions. However, the high-pressure fuel lines experience fluctuating pressures depending on engine speed, which can cause engine vibration and increased noise levels.
The high-pressure common rail injection system represents a more advanced approach, combining direct injection, pre-injection, and electronic control technologies. Unlike previous systems, it separates the injection pressure from the injection timing, allowing precise control of fuel pressure via a common rail. This independence from engine speed improves fuel efficiency, reduces harmful emissions, and enhances cold start performance. However, the maximum injection pressure in common rail systems is generally lower than in pump nozzle systems, typically reaching around 1600 bar. Despite this, the overall performance and environmental benefits make it a popular choice in modern diesel engines.
Artificial Flower&greenery Lei
Orchid Flower Lei,Spider of lily garlands,puakenikeni necklace,maile leaf leis,Ti leaf lei, money graduation lei
Xuzhou Kylin Craft & Gifts Co., Ltd. , https://www.kylincraftandgifts.com