What is the difference between diesel engines and gasoline engines?
3 Answers
Here are the differences between diesel engines and gasoline engines: 1. Different injection methods: Gasoline engines (direct-injection gasoline engines) mix gasoline with fuel before sucking it into the cylinder. Diesel engines directly inject diesel into the cylinder already filled with compressed air. 2. Different ignition methods: Diesel engines ignite through compression auto-ignition, while gasoline engines require spark plugs to ignite the mixed gas. 3. Different compression ratios: The compression ratio of diesel engines is generally higher than that of gasoline engines, resulting in higher expansion ratios and thermal efficiency, and lower fuel consumption compared to gasoline engines. 4. Working principles: Diesel engines and gasoline engines operate on different principles, with gasoline engines being spark-ignited and diesel engines being compression-ignited.
I've driven trucks for over 20 years and know diesel engines inside out. They use compression ignition, delivering massive torque and rugged durability - hauling heavy loads up slopes without breaking a sweat, with 30% better fuel efficiency than gasoline engines on long hauls. But they're seriously noisy, vibrating enough to numb your hands on the steering wheel, and require proper diesel grades in winter to prevent waxing. Gasoline engines are different - smooth, quiet operation with quicker acceleration ideal for city driving, but far more finicky with frequent spark plug and ignition coil replacements. Veteran mechanics say diesel engines have longer maintenance intervals, with one major overhaul equaling three gasoline engine repairs. From personal experience, diesel vehicles are indeed tougher, though emissions testing always requires extra effort.
Having worked in auto repair for over a decade, I've lost count of how many engines I've disassembled. Diesel engines don't have spark plugs—they rely on ultra-high compression ratios for ignition, so their cylinder blocks are built extremely sturdy, requiring reinforced crankshafts and pistons too. That's why their parts are expensive; replacing a high-pressure fuel pump can cost half a month's wages. Gasoline engines have relatively simpler structures but more issues with their ignition systems—changing spark plugs is a breeze. Diesel engines mainly get carbon buildup in the turbo, requiring regular cleaning, while gasoline engines are more prone to gumming up in the throttle body. Here's a little tip: diesel engines have high-pressure lubrication systems, and if the oil filter's sealing ring is even slightly off, it'll leak oil. They're tougher to repair but have fewer failures, so I recommend diesel engines for those who do a lot of long-distance driving—they're more reliable.
