What is the Excess Air Coefficient of an Engine?
3 Answers
Engine excess air coefficient refers to the ratio of the actual air flow (ma) during engine operation to the theoretical air quantity (mfxL0) required for complete combustion of the supplied fuel. This ratio is called the excess air coefficient of the mixture and is denoted by α. Introduction to Engines: The automobile engine is the device that provides power to the vehicle, serving as the heart of the car. It determines the vehicle's power, fuel efficiency, stability, and environmental performance. Depending on the power source, automobile engines can be categorized into diesel engines, gasoline engines, electric motors for electric vehicles, and hybrid systems. Essentially, it is an energy conversion mechanism that transforms the thermal energy from gasoline, diesel, or natural gas into mechanical energy by burning the gas within a sealed cylinder, causing the gas to expand and push the piston to perform work. Engine Maintenance: Maintain good crankcase ventilation, regularly change the oil and oil filter, and periodically clean the crankcase.
I've been into cars for over a decade, and the exhaust gas coefficient is quite crucial. Simply put, it's the ratio of the actual air-fuel ratio to the theoretical ideal value. For example, when you're driving and the engine is burning, if the mixture ratio isn't right—too much or too little air—it can affect performance. A λ greater than 1 means excess air, resulting in cleaner combustion and fewer emissions, but possibly weaker power; a λ less than 1 means insufficient air, which can lead to black smoke and wasted fuel. I've seen many car owners overlook this, resulting in more engine carbon deposits and rising fuel consumption. When tuning an engine, this coefficient can help optimize ignition timing and fuel injection. Maintaining it well can extend the car's lifespan and make it more eco-friendly. In daily use, paying attention to air filter and oxygen sensor maintenance can keep λ within a healthy range.
As a seasoned driver, the exhaust gas coefficient (lambda) is a crucial indicator for me to assess a car's health. It measures how much the remaining air after combustion deviates from the ideal value. A normal lambda close to 1 is optimal, indicating complete combustion without waste. If lambda is too high, the engine may shake or have difficulty starting; if it's too low, it causes excessive exhaust pollution and wastes fuel. Back when I drove older cars, I manually adjusted the carburetor to control this. Nowadays, new cars rely on ECU for automatic control, but understanding the principle helps drive more economically. For example, avoiding frequent short trips and regularly replacing spark plugs can keep the exhaust gas coefficient within a safe range.
