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Perkembangan Sistem Bahan Bakar Motor Bensin
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Tujuan untuk menghasilkan campuran yang homogen
Hisap Kompresi, Injektor mengabutkan BB Percikan Api pada busi dan pembakaran Akhir Hisap, Injektor menyemprotkan BB Proses Penyemprotan Bahan Bakar Pada Mesin DI Terjadi dua Tahap yaitu saat langkah hisap dan kompresi Tujuan untuk menghasilkan campuran yang homogen
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Perbedaan Proses MPI dengan DI
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Pola Aliran Di Dalam Silinder Pada Mesin Multi Valve
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Proses Pembakaran Pada Mesin Direct Injection
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Perbedaan Bentuk Kabutan pada Injektor Model Compact dan Model Cone
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Fuel injection mode map At speeds up to 120 km/h, the Mitsubishi GDI engine operates in Ultra-Lean Combustion Mode. At high speeds or under heavy loads, it automatically switches to Superior Output Mode. It switches to Two-Stage Mixing for hard acceleration from standing starts or low speeds.
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4G93 GDI engine schematic Precise control of both airflow and fuel delivery are crucial to the engine's success.
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Mitsubishi spent years of research to determine the most efficient pattern of in-cylinder airflow. The patented "clockwise tumble" flow of the Mitsubishi GDI engine is the result. Tumble vs. Swirl Conventional engines create "swirl" airflow. But this takes the fuel around the outside of the cylinder. It's impossible to concentrate the fuel, so it doesn't always burn completely. Tumble-shaped airflow solves this problem. The tumble shape breaks up as the cylinder compresses, forming small typhoon-like eddies. These enable fuel to be concentrated around the sparkplug, for outstanding combustion efficiency even with extremely lean air-fuel ratios. A tumble pattern was employed on the Mitsubishi Vertical Vortex (MVV) lean-burn engine. However, counter-clockwise tumble was not feasible for direct injection. Why does it have to be clockwise? If the air tumbles counter-clockwise, it will carry a directly injected fuel spray into the sparkplug, creating a soot buildup that leads to misfires. Also, counter-clockwise flow doesn't allow time for a directly injected spray of petrol to vaporise. These problems were solved by the invention of the Upright Straight Intake Ports, which enabled "clockwise tumble."
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In this mode, at speeds up to 120 km/h, the Mitsubishi GDI engine achieves complete combustion with an air-fuel ratio of 40:1. Conventional engines: 14.7:1 Lean-burn engines: 22:1 Mitsubishi GDI engine: 40:1. Late in the compression stroke, the High-Pressure Swirl Injector sprays fuel in a tight, swirling spiral towards the piston top. This spiral and the "clockwise tumble" airflow keep the fuel spray concentrated around the sparkplug. When the sparkplug ignites, a powerful firestorm is controlled by the spherical cavity. No fuel is wasted. The result: a 20% improvement in overall fuel economy. Ultra-Lean Combustion Mode 1. Piston moves downward. / 2. Piston reaches bottom and begins compression stroke. 3.Fuel is injected late in compression stroke. / 4. Sparkplug ignites mixture.
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In this mode, fuel is injected during the intake stroke in a lengthy, cone-shaped spray to cool the cylinder through evaporation. By preventing knocking through the cooling effect, the 4G93 GDI engine can run at a compression ratio of 12.5, for outstanding power and torque. Furthermore, its high volumetric efficiency creates an effect similar to that of a supercharger. The result: output and torque superior to conventional engines.Superior Output Mode 1. Piston moves downward. 2. Fuel is injected. 3. Piston moves up. 4. Sparkplug ignites mixture.
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This mode was developed specifically for the European 4G93 GDI
This mode was developed specifically for the European 4G93 GDI. Fuel is injected twice: a small amount early, and the majority late. Early injection cools the cylinder. The air-fuel ratio at this point is extremely lean, up to 60:1, so it does not spontaneously ignite. When the rest of the fuel is injected, the air-fuel mixture becomes very rich - about 12:1. This rich mixture is completely combusted. The result: at 650 rpm, a 55 percent increase in torque, for the power to pull away fast. Two-Stage Mixing 1. Piston moves downward. 2. Fuel is injected. 3. Fuel is injected again during compression stroke. 4. Sparkplug ignites mixture.
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Perbedaan Konsumsi Bahan Bakar antara Mesin Bensin dan Diesel
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