tag:blogger.com,1999:blog-369941762441967690.post3112653196812789901..comments2022-11-26T01:46:19.151-08:00Comments on EV Z3: On Power Steering and a "Normal" Feeling DriveTim Catellierhttp://www.blogger.com/profile/02801279544184321528noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-369941762441967690.post-53877567071921895392012-10-29T11:08:39.889-07:002012-10-29T11:08:39.889-07:00Hello Christian,
I'm eager to see your final...Hello Christian, <br /><br />I'm eager to see your final design for the power steering pump system I can tell you that for my car, it turned out that simply having the pump on all the time when the car ignition is turned out on to the easiest and safest solution. Having a circuit to adjust it's power based on speed might be nice, but it's unnecessary. The car drives perfect with out it. <br /><br />The additional power it draws from the battery pack is so small I just do not care. I could turn the car on and it would take 40 hours to use up all the energy in the battery pack. In a 1/2 hour trip, the pump draws only enough power to move the car less than 1 kilometer. It's simply not enough energy for me to worry about.<br /><br />TimTim Catellierhttps://www.blogger.com/profile/02801279544184321528noreply@blogger.comtag:blogger.com,1999:blog-369941762441967690.post-69909642227661595612012-10-28T09:55:43.396-07:002012-10-28T09:55:43.396-07:00Hi Tim,
I followed your blog. Great inspriation. C...Hi Tim,<br />I followed your blog. Great inspriation. Converting a Porsche Boxster myself, I have the same problem. I found a guy who build me a custom speed sensitive control unit. The only thin you need is some sort of speed signal which you might find feeding into your radio. The pump stops a a programmable speed lets say 45 mph and starts again at 45 mph. Once you roll to a stoplight it stops the pump after 10 sec delay and starts right when you drive again. The 10 sec. should also cover any parking. The unit is 60 Euros. See my blog incl. a short video. http://eboxster.blogspot.de/2012/10/steuerung-der-servopumpe.html <br />Best Regards<br />ChristianAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-369941762441967690.post-80150377124496507852012-07-25T16:21:57.947-07:002012-07-25T16:21:57.947-07:00Boo,
You're absolutely right that this is the...Boo,<br /><br />You're absolutely right that this is the proper way to do it. Power steering assistance is modulated vs. the speed of the car. To do that, you need to read the CAN BUS signal put out by the ECU first. Then you need to take that signal and process it so that you can intelligently vary the power to the pump so you get the variable assist steering. <br /><br />The good news is that the MR2 pump already has a module built in that will vary the power it draws depending on the signal that's sent to it. Here's were I run into problems. I don't know anything about finding or interpreting the signal from the ECU that indicates speed; and I don't know if it's even in the format that would control the pump properly. <br /><br />The bottom line is that I simply don't know how to do it. If someone smarter than me was willing to stop by and show me how, I'd be eager to learn all about it. But as yet, no one has. <br /><br />The good news is that since the pump is a DC motor, it tends to draw the current it needs. It's sort of self regulating in that regard. DC motors do a great job of spinning at a specific RPM based on the voltage of the current flowing to them. If you try to slow them down, they simply draw more current to keep the same RPM. Put more load on them, the draw more current until there's no more to draw. Because of that, I really never notice a difference in the way the steering feels whether I'm going slow or fast. It kind of works itself out. <br /><br />Thanks for the comment.<br /><br />TimTim Catellierhttps://www.blogger.com/profile/02801279544184321528noreply@blogger.comtag:blogger.com,1999:blog-369941762441967690.post-44026452480909148832012-07-25T13:33:43.634-07:002012-07-25T13:33:43.634-07:00Hi, just saw your blog. You probably posted this ...Hi, just saw your blog. You probably posted this a long time ago, and sounds like you resolved the problem, but might you base your power steering assistance on a certain speedometer trip point instead? Like if you are going 10mph or less, presumably that's when you're in a parking lot, and really the only time you need power steering anyway...<br />BestBoo plus Aroohttps://www.blogger.com/profile/01408199893389509666noreply@blogger.com