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front wheel drive- powering only one half shaft

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  • front wheel drive- powering only one half shaft

    A few days ago I started wondering about how to add auxiliary power to a front wheel drive vehicle, say electric assist. You could add something to the engine, like replacing the alternator with a combo alternator/motor, but that involves the engine. Apart from that, there are the two half shafts. The idea was to add some kind of custom hydraulic drive that would surround one or both half shafts and power them directly. Two would be more complicated than one, hence the question- could one half shaft be powered this way without having steering or other control issues? Both front wheels would get powered anyway, since they are coupled through the differential.

    Stupid idea, possibly. But the question is, would driveability be adversely affected?
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    I can see it being affected in some conditions....

    How about powering the REAR wheels? An electric drive and differential would work fine, and would provide a boost without invasive actions on the front drive.
    1601

    Keep eye on ball.
    Hashim Khan

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    • #3
      The differential is key since the speed of each shaft changes depending on the direction of travel. That's what differentials do. Adding to or changing the speed of a half shaft could affect control. Adding assist would have to go in front of the differential or have some pretty complicated control to sense when one shaft turns at a different speed than the other. A note here: Some cars already sense wheel speed changes to control antilock brakes and/or traction control.

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      • #4
        Like Ken was precluding
        . There is not enough speed to make some good voltage. And they are wasting fuel doing the stupid experiment. .I dont have any money. I want to help get these generators to where they are needed...
        My old yahoo group. Bridgeport Mill Group

        https://groups.yahoo.com/neo/groups/...port_mill/info

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        • #5
          Your bigger challenge in adding electric assist to an existing design is to do it smoothly and in a way that will play well with the existing controls and safety features. You might end up with jerking, cogging or failure to work with cruise control, ABS, etc.


          What objective are you trying to achieve? Mileage? Emissions? Acceleration? Torque for towing or hills?

          Dan
          At the end of the project, there is a profound difference between spare parts and extra parts.

          Location: SF East Bay.

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          • #7
            I don't have a particular goal in mind, but perhaps a useful thing would be able to bring the vehicle from stopped up to say 50 or 60 k on the auxiliary power, and also store the reverse of that- decelerating it to near stopped from any normal steady speed. The engine would be left running, and clutched in probably about where you'd be in the second from highest gear.

            I still think a flywheel/hydraulic system would work here, since it's not needed to propel the vehicle for any distance. The recoverable energy would be a fixed quantity- even at 100 kph the amount of energy is not a huge quantity and the system could be fairly small and light. The trick would be to design a hydraulic 'translation device' which would be small enough to mount in the limited space available where the half shaft resides (assuming the original idea). Of course in a conventional rear wheel drive you have a couple points where you could access the drive shaft easily enough to add such a system.

            If any such thing could be added to a front drive vehicle by using the rear wheels, then some access to driving the rear wheels would be needed. You would likely have to remove the wheels and sandwich a drive 'disc' of some sort between the wheel and the brake drum or disc. It would be better if you could drive an axle directly, but I don't think you would normally have access to that on a front drive vehicle- except for the front wheel drive half shafts. You could always do a mechanical conversion to the rear and sub in parts from a rear wheel drive- probably something with independent suspension so there isn't too much change required in the original suspension.

            That's kind of an interesting concept- four wheel drive with the rear wheels using the auxiliary power system, whatever it is.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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            • #8
              How much/long will this be used? If only to get out of being stuck or all the time?

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              • #9
                I am not quite understanding your application.
                If you are getting the power assist from your existing engine, aren't you robbing Peter to pay Paul?

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                • #10
                  I think the closest thing you get to "free" energy is a flywheel, which still has to be started so it's not free either. For example, a hay baler will work off the PTO without a flywheel if the tractor is big enough - but the flywheel helps smooth out the baling and handles clumps. If I understand the original question, you are looking for short term assistance and that is one mechanical way to do it. However, flywheels are generally pretty large - the one on my JD baler weighs about 200 lbs.

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                  • #11
                    Originally posted by darryl View Post
                    A few days ago I started wondering about how to add auxiliary power to a front wheel drive vehicle, say electric assist. You could add something to the engine, like replacing the alternator with a combo alternator/motor, but that involves the engine. Apart from that, there are the two half shafts. The idea was to add some kind of custom hydraulic drive that would surround one or both half shafts and power them directly. Two would be more complicated than one, hence the question- could one half shaft be powered this way without having steering or other control issues? Both front wheels would get powered anyway, since they are coupled through the differential.

                    Stupid idea, possibly. But the question is, would driveability be adversely affected?
                    Your probably talking less than 10 ponies so not thinking your going to be getting into a whole lot of torque steer or anything too serious, but your idea should just be shelved for all kinds of reasons most of all complications and extra weight and way to many conversion systems, along with taking power from the engine to then add back into the system after you've converted said power to electricity to then run a motor to then run a hydraulic pump, to then run a hydraulic motor,

                    Your better off to just focus on tweaking the engines efficiencies - much can be done, running synthetics in all the drivetrain - proper max tire inflation and also hypermileing driving techniques

                    when gas was 4 bucks a gallon it's how I consistently got over 50mpg's out of my toyota tercel that was only rated 33

                    big improvement

                    took an exhaust pyrometer and gauge - an air fuel mixture gauge and a custom made potentiometer tapped into my computers oxy sensor link...

                    total extra car weight --- maybe about 1lb
                    complications? done in a day.

                    Comment


                    • #12
                      It's old, old news. been done for a decade at least.

                      A neighbor has a hybrid of that type. I forget if it is a honda or what, but it combines a gas and electric motor, NOT the ways a Prius does, it seems NEVER to run on the electric alone. Apparently it runs on a small gas engine, and uses the electric as a boost only.

                      Seems stupid to me, but apparently it really does work.
                      1601

                      Keep eye on ball.
                      Hashim Khan

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                      • #13
                        Where they shine is in the city - regenerative braking puts city fuel economy almost as good as highway and that's saying something...

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                        • #14
                          I even took it so far as to create a progressive throttle cam, helps you not overshoot your mark and keeps you in granpa mode, still had full throttle if you really wanted to put the effort into it for when you needed it,
                          this is stock;



                          this is modified;


                          machining custom values into a potentiometer;



                          glowshift gauges installed with ability to adjust mixture ratio's and NOT melt a hole in my pistons... ;

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                          • #15
                            Stay away from hydraulics, they are horribly inefficient.
                            https://www.youtube.com/channel/UCIF...7S66kX1s8rd0qA

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