三菱4A91T发动机的结构及使用的技术方法

The 4A91T engine is based on Mitsubishi's 4A91 engine technology, jointly developed by Shenyang Aerospace and Mitsubishi, and launched in 2013. It was recognized as the "2014 Power Pioneer" for its strong power and fuel efficiency in the same displacement category. With a maximum torque of 215 N·m and a power output of 115 kW, it stands out in its class.

Although the 4A91T is not the most advanced engine in today’s market, it is considered a mid-to-high-end configuration in domestic models. Its compact size, high performance, low fuel consumption, and environmental friendliness (meeting Euro V standards, with an upgrade to Euro VI) have made it a popular choice in China. The reliability of the 4A9 series is widely acknowledged, with a common saying that “the car can be scrapped, but the engine doesn’t need a wrench.”

Here are some key features of the 4A91T engine:

1. Turbocharger: The 4A91T uses Mitsubishi's original turbocharger technology, with core components such as the turbine, high-speed bearings, and pump wheel assembly imported from Japan. Only the turbine housing is produced and assembled domestically. This system boosts air intake using exhaust gases, increasing engine efficiency and performance. Compared to naturally aspirated engines, it improves power by 30% and torque by 40%, while maintaining similar fuel consumption. For example, the DX3 and DX7 models equipped with the 4A91 and 4A91T engines have similar fuel consumption of 5.8L and 5.9L per 100 km, respectively.

The engine's external characteristics show that the turbocharger starts working at low RPMs, significantly improving torque even before 2000 RPM. This results in better acceleration and a wider torque range (2000–4500 RPM), offering more driving pleasure.

Good driving habits are essential for both performance and fuel economy. Here are some tips to maximize efficiency:

(1) Shift gears at around 2000–2500 RPM to keep the engine running in its most efficient range.

(2) When starting or driving at low speeds, gently press the accelerator to allow the engine to run at higher RPMs, where torque is stronger and fuel efficiency is better.

(3) Avoid sudden acceleration, as this forces the engine into a richer fuel mixture, which increases emissions and reduces combustion efficiency.

(4) Try to avoid driving in high gear at low RPMs, as this can lead to carbon buildup and reduced performance over time.

(5) Regular highway driving helps clean carbon deposits, maintaining engine efficiency and prolonging its life.

2. DOHC with MIVEC Variable Valve Timing: The MIVEC system in the 4A91 allows for variable valve timing and lift, optimizing both performance and fuel efficiency across a wide range of RPMs. Unlike VTEC and VVTI, MIVEC offers both functions simultaneously, making it more advanced.

3. Aluminum-Magnesium Alloy Cylinder Block: Using aluminum for the engine block reduces weight, improves heat dissipation, and enhances fuel economy. However, this material is more expensive to produce and has a lower yield rate.

4. Resin Intake Manifold and Reverse Exhaust Manifold: By using resin for the intake manifold and placing the exhaust manifold in a reverse position, the engine achieves lighter weight and lower fuel consumption compared to traditional metal designs.

5. Timing Chain Drive: Unlike many older engines that use timing belts, the 4A91 employs a timing chain, which lasts the entire lifespan of the engine without needing replacement. This saves users significant maintenance costs over time—up to 5000–10000 RMB in total lifetime expenses.

6. Electronic Throttle Body: The electronic throttle works in conjunction with the electronic accelerator pedal, allowing the ECU to control the throttle position precisely via a DC stepper motor. This improves fuel efficiency and reduces harmful emissions, helping the 4A9 series meet strict Euro V emission standards easily.

7. Independent Ignition System: Each cylinder in the 4A91 has its own ignition coil, providing higher ignition energy and more precise timing control, leading to more complete combustion and better performance.