Ford's answers to the NHTSA 6.7 Investigation
There was a request for a link to Ford's answer's to the NHTSA investigation posted on a previous thread, since closed. Here is the link: Ford's NHTSA Answers to the 6.7 investigation This PDF i...
Forum Discussion
A big accumulator is a negative in many ways, from keeping fuel in it that is in a hot place, pressurized.
Low volatility of diesel mean low fire risk, but still, don't want that big pot squirting out at 2,000 bar.
At that pressure, it will go through many things, thick gauge steel, shoot through a body.
I can understand why using a common rail to also be accumulator --- changing the common rail to a larger diameter is a relatively simple design change, with significant costs, plus also time before it fully pressurize on start.
Still am not sure if the issue is accumulator / dampening -- vs. cavitation at the low end of the pump, or coating ablation.
One way to play around with the accumulator ( a die cast part, from what it seems) is to add odd shapes / baffles in it to alter its wave properties.
Again, need a good simulation, but once it is done --- shouldn't add more than marginally to the cost --- maybe 20 euro cents or so per unit for some extra metal, one time tooling charges to shape the die.
Low volatility of diesel mean low fire risk, but still, don't want that big pot squirting out at 2,000 bar.
At that pressure, it will go through many things, thick gauge steel, shoot through a body.
I can understand why using a common rail to also be accumulator --- changing the common rail to a larger diameter is a relatively simple design change, with significant costs, plus also time before it fully pressurize on start.
Still am not sure if the issue is accumulator / dampening -- vs. cavitation at the low end of the pump, or coating ablation.
One way to play around with the accumulator ( a die cast part, from what it seems) is to add odd shapes / baffles in it to alter its wave properties.
Again, need a good simulation, but once it is done --- shouldn't add more than marginally to the cost --- maybe 20 euro cents or so per unit for some extra metal, one time tooling charges to shape the die.
