Which is More Prone to Carbon Buildup: Multi-Point Fuel Injection or Direct Injection?
2 Answers
Comparing direct injection and multi-point fuel injection, direct injection is relatively more prone to carbon buildup. Although both direct injection and fuel injection generally face carbon buildup issues, direct injection is more pronounced. However, with technological advancements, this problem is expected to be gradually overcome. Below is an introduction to direct injection and multi-point fuel injection: 1. Definitions of Direct Injection and Multi-Point Fuel Injection: Multi-point fuel injection engines have injectors installed on the intake pipe of each cylinder, meaning fuel is injected into the cylinder from multiple points. Direct injection engines have injectors installed inside the combustion chamber, allowing fuel to be directly injected into the cylinder's combustion chamber, while air enters through the intake valve to mix with the fuel and form a combustible mixture. 2. Differences Between Direct Injection and Multi-Point Fuel Injection: Multi-point fuel injection technology is still relatively mature, and due to its simple structure, maintenance is not necessarily very difficult. Direct injection engines have a more complex structure, and the technology has not yet reached a mature stage of development. Combined with the significant carbon buildup issue, multi-point fuel injection still has an advantage in terms of service life.
With over a decade of experience in auto repair, I've noticed that carbon buildup is more common in direct injection engines, especially around the intake valves. Since fuel is injected directly into the cylinders, unlike multi-point fuel injection which also washes the intake valves, dirt accumulates more and more, clogging up like a pile of garbage. I've seen many owners of direct injection cars experience reduced engine power and skyrocketing fuel consumption after 30,000 to 50,000 kilometers, and upon inspection, it turns out to be severe carbon buildup. Multi-point fuel injection fares a bit better, as the fuel incidentally cleans the valves, though it's not 100% clean either. Regularly using fuel additives can help—don't wait until the problem becomes severe, as repairs can be costly and time-consuming, often requiring engine disassembly for a thorough cleaning. In short, based on my experience, direct injection is more prone to carbon buildup issues, so it's important to weigh the pros and cons when choosing a car.
