Announcement

Collapse
No announcement yet.

CDI engine technical questions particularly on throttle workings

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • CDI engine technical questions particularly on throttle workings


    Hello guys (and gals) thanks for letting me in here. I live in North Wales in the United Kingdom. I am not far from the English city of Chester (just in case any non-UK people are reading this)
    I am building a BMW K100 motorcycle with a 2009 Smart CDI Diesel engine. Forgive me therefore if I ask some stupid questions.
    Just to give a few background details in case anyone isn’t familiar with what’s needed, the Smart gearbox is not used and an adapter plate is made to go between the motorcycle gearbox (which is shaft drive) and the rear face of the Smart engine.
    The engine sit bolt upright and the bottom of the sump is cut off to make it flat and give ground clearance.
    The exhaust manifold and turbo assembly is turned upside down using an adapter plate. The turbo oil drain goes into the dipstick tube and the dipstick is no longer needed. There is an oil sight glass in the side of the sump.
    The Smart clutch is not used and the motorcycle clutch assembly is mounted onto the Smart flywheel. The Smart flywheel no longer becomes a friction surface. This is necessary because of the rather odd way which the motorcycle gearbox (in this case) works having a very short splined input shaft and with the clutch operating pushrod going through the centre of that input shaft rather than around the periphery using a conventional release bearing. BMW did their own thing with this motorcycle!
    Here is the clutch carrier installed on Smart flywheel

    So, moving swiftly on, I have some questions about the throttle arrangement for the diesel motor and other things

    The engine I have is incomplete and I’m trying to ascertain what is missing. I know the electronics are going to be a nightmare but I will buy a Specialist Components ECU and wiring diagram which gets rid of all the extra non-required connections such as the gearbox, EGR, particulate filter et cetera.

    All the throttle assemblies photographs I have seen on the Internet show them attached with 4 bolts.

    I have seen a photograph of the plastic manifold on its own with a rubber adapter on the end but nothing for 4 bolts.

    http://www.ebay.co.uk/itm/2014-SMART...0AAOSweW5VGXO0

    This what I have

    I have searched on the Internet in vain for a parts diagram

    My Smart Diesel engine is missing complete throttle assembly. I have nothing other than the plastic composite inlet manifold. Can somebody tell me (part numbers and photograph/diagram/illustration will be fantastic) what goes between the plastic inlet manifold and the pipe from the turbo?

    It seems that as soon as you put the words Smart Car in front of whatever you’re looking to buy, the price trebles! Parts for normal Mercedes seem to be much cheaper.
    Therefore, is there another throttle body from something else which could be substituted? I see that some people running petrol cars have replaced them and I happened to read a thread a short while ago where someone had used a Corsa unit but that was a petrol engine. Any suggestions in that respect be really useful.

    Here is a photograph of the pump. Is this the only pump there is? Being fitted in a motorcycle, the tank would normally gravity feed to the fuel pump. Does everyone think that will be sufficient or should I put another electric pump in to feed the diesel pump? I guess the short pipe (with the little Red Hat) is the feed and the long pipe with a little Red Hat is the return. Is there anything magic about the feed and return or does the return simply empty back into the tank any excess pressure? Does anyone know how much pressure should be in there? The motorcycle had fuel injection and therefore there is a pump inside it which could be used but I think it would need a pressure regulator because it was originally to drive petrol injection.


    Now for the really stupid questions. These cars have electronic pedal. Is there no mechanical connection between the throttle body and the foot pedal or is there some kind of box somewhere (not the ECU) which I’m going to need?

    What does this zinc plated bracket do? It looks like it used to have a cable in it.


    It’s going in a motorcycle and therefore there is no need (lots of fresh air around) for an intercooler. Also, the EGR is binned and the new Electronics takes care of that.

    I think this is the old EGR take off in the zorst manifold which is going to be blanked. Can someone please confirm?

    Finally, I know that the turbo runs on plain bearings. I am aware of the necessity for good oil. How much play (if any) should be discernible in the turbo shaft?
    Yes, I know it’s a big and ambitious project but it has been done before and I know that it can be done and hence, it will be done. I am seriously committed to this and have already set aside the funds and got the motorbike and the Smart engine of course.
    The clutch is already machined into the flywheel cannot be assembled totally until the gearbox is lined up. I will get the mounting plates laser cut next week.
    Thanks for replies everyone.
    Regards
    James





  • #2
    Originally posted by touchwoodsden View Post

    All the throttle assemblies photographs I have seen on the Internet show them attached with 4 bolts.

    I have seen a photograph of the plastic manifold on its own with a rubber adapter on the end but nothing for 4 bolts.


    My Smart Diesel engine is missing complete throttle assembly. I have nothing other than the plastic composite inlet manifold. Can somebody tell me (part numbers and photograph/diagram/illustration will be fantastic) what goes between the plastic inlet manifold and the pipe from the turbo?
    Intercooler and being a diesel there's no need for a throttle.


    Originally posted by touchwoodsden View Post
    It’s going in a motorcycle and therefore there is no need (lots of fresh air around) for an intercooler. Also, the EGR is binned and the new Electronics takes care of that.
    I beg to differ. Without an IC you will barely make any more power than if you omit the turbo altogether,

    Comment


    • #3
      Originally posted by Thrumbleux View Post

      Intercooler and being a diesel there's no need for a throttle.




      I beg to differ. Without an IC you will barely make any more power than if you omit the turbo altogether,
      Thanks for the reply.
      The reason I ask about the throttle body is because I have seen these.
      http://www.ebay.co.uk/itm/SMART-FORT...gAAOSwQPlV8Ulz
      clearly marked 800 mL CDI.
      I just don’t know how the / air mixture is controlled in a diesel
      With regard to the lack of intercooler, there have been many such projects made without. Indeed, there was even a commercial motorcycle using the same engine also without an intercooler of which they made a few hundred. It was the price of just under £20,000 which killed it I think. I can put an intercooler, if needed, sitting sideways.
      If you Google Eva Trak 800CDI it will show some pictures and some video.
      Regards

      Comment


      • #4
        It is possible it runs a throttle valve (Mercedes used to use them in the past to create a vacuum signal for fuel metering). A (specific) CDI owner will soon advise I suspect.
        Air/mixture is what is called 'quality governed'. Basically as much air as the engine can physically ingest then add fuel appropriate to the torque output required. The values for fuelling are stored on the ECU map and reads a host of parameters (throttle pedal position, manifold pressure, temps, etc) then adjusts the delivery pressure to the injectors via a solenoid control valve on the fuel rail. The injector durations are fixed.

        For the extra hassle, try and fit an intercooler. Without one the air loses density such that the actual mass of air entering the cylinder is much lower than it could be. Additionally, the cycle starts at a higher temp which persists throughout the remainder of the cycle - leading to higher heat loss and lower efficiency.

        Comment


        • #5
          Originally posted by Thrumbleux View Post
          It is possible it runs a throttle valve (Mercedes used to use them in the past to create a vacuum signal for fuel metering). A (specific) CDI owner will soon advise I suspect.
          Air/mixture is what is called 'quality governed'. Basically as much air as the engine can physically ingest then add fuel appropriate to the torque output required. The values for fuelling are stored on the ECU map and reads a host of parameters (throttle pedal position, manifold pressure, temps, etc) then adjusts the delivery pressure to the injectors via a solenoid control valve on the fuel rail. The injector durations are fixed.

          For the extra hassle, try and fit an intercooler. Without one the air loses density such that the actual mass of air entering the cylinder is much lower than it could be. Additionally, the cycle starts at a higher temp which persists throughout the remainder of the cycle - leading to higher heat loss and lower efficiency.
          Thank you. I take the point about cooling the inlet charge to increase the air density and I was actually aware of that in the past.
          At this stage, I am concentrating on getting all the parts I need, the engine fitted and getting it to make a noise of any description preferably a noise that continues rather than lasts half a second or so!
          I know that one owner has fitted an intercooler behind the engine in a place where the motorcycle battery would normally have gone but he’s fitted the engine at the same inclination it is in the car albeit front to back rather than side to side and he has counterbalanced it by putting the car battery in the motorcycle on the opposite side to the sloping engine. To be honest, it looks a mess. If anything, I would put the intercooler sideways (other motorcycles cool the engine that way) with a constant running fan.
          Regards

          Comment


          • #6
            What is in your favour is that the OEM fit IC is a very compact unit. It even has a fan attached.

            Comment


            • #7
              Originally posted by touchwoodsden View Post
              What does this zinc plated bracket do? It looks like it used to have a cable in it.
              Bracket for vacuum pipe. Comes from vacuum pump and goes to brake booster.

              Comment


              • #8
                Originally posted by tolsen View Post
                Bracket for vacuum pipe. Comes from vacuum pump and goes to brake booster.
                I can get rid of the bracket then Thanks Tolsen.
                James

                Comment


                • #9
                  can i just ask why are you fitting a diesel lump in to a bike?

                  i asked a mate of mine who works with bikes why there isnt a diesel bike and his reply was why would you want a diesel bike... you get well over 70MPG depending on bike and they are cheap enough to run

                  Comment


                  • #10
                    Originally posted by lalli_d1 View Post
                    can i just ask why are you fitting a diesel lump in to a bike?

                    i asked a mate of mine who works with bikes why there isnt a diesel bike and his reply was why would you want a diesel bike... you get well over 70MPG depending on bike and they are cheap enough to run
                    Why? Because I can. There are hundreds of people who fitted different diesel engines into motorcycles but I didn’t want one out of a dumper truck!
                    The problem with motorcycles is actually that they are no longer cheap to run. It’s cheaper to run a car. However, that isn’t the reason, it’s the engineering challenge as much as anything else.

                    Incidentally, I spoke to the guys who produced the stand-alone ECU and the say that this runs with no throttle valve, no MAF and it just has the manifold pressure sensor along with all the other electronics of course. So that answers a massive lump of the reason for the post.

                    Bearing in mind that he knows more about diesels as he actually designed the ECU, he said there is no point in fitting an intercooler in a motorcycle unless I want the engineering challenge of doing so. We shall see.
                    Expect more stupid questions on which sensor is which and which pinouts on the ECU are which because the description is almost in a foreign language

                    Comment


                    • #11
                      Neil Laughlin had lots of trouble with an ECU from a certain unnamed ECU builder. Perhaps same as yours?

                      Comment


                      • #12
                        Originally posted by tolsen View Post
                        Neil Laughlin had lots of trouble with an ECU from a certain unnamed ECU builder. Perhaps same as yours?

                        Specialist Components from Norfolk?
                        I thought Neil did his own ECU.

                        Comment

                        Ad Widget

                        Collapse
                        Working...
                        X