Absolutely right. Indirect refers to the use of a precombustion chamber. This was needed to start the combustion process in a mild manner, to avoid what would have been intolerable NVH levels in a passenger car. The first VW and Peugeot/Citroen engines from the late 1970s onwards were good examples. These engines had distributor pumps and around 175bar injection pressures.
When higher injection pressures, then better injection control, became possible, true direct diesel injection was feasible and the VW TDi was born. A bowl in the top of the piston helps swirl the mix. Early TDi still used the ditributor pump. Peugeot/Citroen and Bosch/Siemens put their efforts into the HDI, commonrail, system, which took a long time to develop. Commonrail originally had up to 1300 bar available and a small number of injection events but I think may have up to 11 shots per cycle now. HDi was released in 1999 and enabled an incredible advance in every area- as featured in Pivoslaw's car, the 307. VW meanwhile went the PD route to get high pressures - for a while. That got them 2000 bar. Now VW group have ditched PD for commonrail - for lower emissions, I understand.
How do I know all this? Been driving diesels since 1990 and just swapped a HDi engined car for a noisier PD-engined one!
Please excuse my ignorance of lots of other diesel car makers - my slant on it is that VW and Peugeot/Citroen (or Bosch, Siemens and Delphi) led the way and others followed. For example, Ford have teamed up with Peugeot/Citroen for their commonrail diesels. (You really didn't want to drive a Ford-engined Ford diesel in the 1990s!)
Simon
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Quote:
Originally Posted by rmay635703
Wrong, I believe you are mixing up what direct and indirect mean in terms of a diesel versus a gasser for example.
In a diesel Indirect injection occurs in a prechamber and was common practice on most smaller auto motors up until very recently, my 89 6.2 diesel suburban is not true direct injection for example.
Cheers
Ryan
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