lowenbrau
SILVER Star
I got a PM asking what the diaphragm does and decided to post it up for all to see. Feel free to add corrections if need be.
I should post this somewhere because it's what makes 3Bs cool.
The system is based on an injections system called the Ricardo Comet Mk IV, invented in England. Typical diesels have a big pipe going into the intake manifold and no restriction on air. The speed of the engine is controlled by injecting more or less fuel. The air/fuel ratio sorts itself out once the engine meets the speed of the operator is asking of it. With the Ricardo system, there is a butterfly or throttle at the entrance to the intake and there is a pipe in the air stream above and below it. These pipes run to each side of the diaphragm which directly connected to the fuel rail of the injector pump. When the butterfly is closed, the engine is trying to draw air in and there is a difference in the vacuum on each side of the butterfly, that difference is transferred to the diaphragm and the fuel real is shut down. The engine runs very slowly. AS the operator opens the throttle, the difference in vacuum is reduced and the fuel rail begins to open. The engine begins to accelerate. All the while the air fuel radio is optimized. Once the throttle is opened completely there is no difference in the vacuum above or below the butterfly and the diaphragm moves to its natural position, maximum fuel. The engine accelerates until the throttle is let off or the centrifugal over speed limiter pulls back on the fuel at 4250 RPM. It’s a brilliant system considering its all mechanical. Computers need not apply!
I should post this somewhere because it's what makes 3Bs cool.
The system is based on an injections system called the Ricardo Comet Mk IV, invented in England. Typical diesels have a big pipe going into the intake manifold and no restriction on air. The speed of the engine is controlled by injecting more or less fuel. The air/fuel ratio sorts itself out once the engine meets the speed of the operator is asking of it. With the Ricardo system, there is a butterfly or throttle at the entrance to the intake and there is a pipe in the air stream above and below it. These pipes run to each side of the diaphragm which directly connected to the fuel rail of the injector pump. When the butterfly is closed, the engine is trying to draw air in and there is a difference in the vacuum on each side of the butterfly, that difference is transferred to the diaphragm and the fuel real is shut down. The engine runs very slowly. AS the operator opens the throttle, the difference in vacuum is reduced and the fuel rail begins to open. The engine begins to accelerate. All the while the air fuel radio is optimized. Once the throttle is opened completely there is no difference in the vacuum above or below the butterfly and the diaphragm moves to its natural position, maximum fuel. The engine accelerates until the throttle is let off or the centrifugal over speed limiter pulls back on the fuel at 4250 RPM. It’s a brilliant system considering its all mechanical. Computers need not apply!