Julian Edgar, 50, has been writing about car modification and automotive technology for nearly 25 years. He has owned cars with two, three, four, five, six and eight cylinders; single turbo, twin turbo, supercharged, diesel and hybrid electric drivelines. He lists his transport interests as turbocharging, aerodynamics, suspension design and human-powered vehicles.
Picking gauges
It’s not often that you get a clean slate in terms of designing an instrument panel.
With my Honda Insight project, where the standard instrument panel is being ditched and replaced with (primarily) a MoTeC CDL3 digital dash, to some extent the type of display becomes obvious – it’ll be dominated by the MoTeC unit.
But what about the factory-fitted warning lights – things like ABS, EPS (electric power steering) and airbag malfunction indicators? And how will high beam, low beam and the action of the indicators be shown? And will there be data that I will want to be able to see but the MoTeC dash won’t easily show?
Despite the dash not likely to be installed for many months, I’ve been mulling over these ideas.
At this stage – and things may well change – this is what I am thinking I’ll need:
Warning lights for:
– high beam
– low beam
– left indicator
– right indicator
– EPS
– ABS
– airbag
– handbrake / braking system fail
Small backlit numerical LCDs for:
– high voltage battery voltage
– electric motor current flow
MoTeC dash display of:
– engine rpm
– coolant temp
– fuel level
– road speed
– manifold pressure
– intake air temp
– gear
– oil pressure
– oil temperature
– turbo exhaust back-pressure
– water/air intercooler pump drive voltage
– 12V battery voltage
Some of these MoTeC-displayed parameters (eg intake air temp and rpm) will be communicated via the CAN bus from the M400 ECU.
One parameter (selected gear) will be internally calculated in the dash, while other parameters (like oil temp and pressure) will require dedicated sensors.
Note that the MoTec dash allows different data to be displayed depending on the mode selected – so not all of these things will be available all at once!
On the list above there are a couple of unusual ones.
I want to be able to see turbo exhaust back-pressure because, in order to provide low rpm torque, the turbo that is being used is small. However, if as a result of its small size, the exhaust back-pressure is overly high, then fuel economy will suffer. It’ll be good to be able to see this figure.
So why show the water/air intercooler pump drive voltage? The pump will be varied in speed by the ECU. This is needed because I want to control the intake air temp, rather than just keep it as low as possible. For much of the time, I would expect that the pump will be operating at less than full speed. Displaying pump drive voltage will allow me to see at what speed the pump is being driven. Not only will this be interesting in itself, it will also allow me to assess how effective the control strategies are that are being used to operate the pump.
As I said, all still a long way off, but I need to start sourcing bits and installing sensors right now.
on April 4th, 2014 at 6:01 am
From the above I’m presuming you’re not going to enable the optional inputs on the CDL3? If you did the dash could be programmed to flash up warnings for malfunctions, which could simplify things a lot. You could use the inputs from the M400 as well, if there are any spare.
You could also use logging in the ECU or dash to analyse water-pump voltage etc. which could be a lot more revealing than real time monitoring.
It’s been a long time since I last used a MoTeC dash but I remember it being quite straightforward to arrange the display to display certain things at certain times/based on certain parameters without user intervention. The flexibility is mind boggling.
on April 4th, 2014 at 9:01 am
Put calibrated strain gauges on a driveshaft and log output torque. Then add rpm and fuel flow to calculate a real time BSFC. Super fuel saver.
Also AC compressor engagement?
on April 4th, 2014 at 3:35 pm
Anthony: The extra inputs are enabled. You’re suggesting I use these to display fault warnings from other ECUs like ABS? I hadn’t thought of that.
Ford Man: I don’t think this dash can do such calculations – it’s not the full maths-enabled ADL. Not sure re air con.
on April 4th, 2014 at 6:04 pm
Another thought re: exhaust backpressure, I’ve seen an aftermarket two-port wastegate actuator for internal wastegates. Could you apply vacuum to one of those ports (usually the top port) to open the wastegate without needing boost pressure? This would dull response a little from cruise, but would eliminate much of the restriction of the turbine.
on April 5th, 2014 at 6:32 pm
Ben: thanks for that.
I am really not sure how much the turbo will be working – for example, I expect it will be constantly on boost at 100 – 110 km/h cruise, but not obviously in 5th gear at 1100 rpm at 60 km/h. Yours is a good option if I find that backpressure is in fact measurably high even when not on boost. (The other way would be just to drive the wastegate flap directly with an electric servo operating through a lever. Is there any reason why this is not done?)
on April 5th, 2014 at 9:02 pm
Not sure, but there are some boost controllers capable of driving a stepper motor as their output. They only control a pneumatic valve though. That’s the only real reason I can think of, but your Motec may be able to handle directly driving such a linear stepper motor. Mapping it would be an issue (and it would have to have some closed loop features).
The other reasons for lack of adoption would be requirement (most people just want closed until boosting), and people being generally afraid of new things. But they took to normal electronic boost
You may want to look into how variable geometry turbochargers are controlled, I can see the same kind of control strategies being used.
on April 5th, 2014 at 9:07 pm
Not sure whether my last post got through? But I found what you are looking for at http://www.stoneridge.com/products/turbo-charger-electric-wastegate-actuator/
on April 7th, 2014 at 4:16 pm
One possible issue with bypassing the exhaust turbine is the intake still needs to suck through the compressor so less exhaust spinning it up would lead to greater restriction on the inlet side,
on April 7th, 2014 at 6:35 pm
I don’t think that would be an issue, the turbo will still be spinning fairly quickly, it’s not like you can get *all* the exhaust to flow through the wastegate, especially when it’s as small as most internal ones are (assuming Julian is running an internal wastegate, for packaging reasons I think he would be).
on April 10th, 2014 at 6:03 am
Julian, I’m assuming the warning lights are activated by ground switches or similar in (say) the ABS ECU, so rather than wire that to a bulb you could wire it to a voltage input in the dash.
Another thing, just in case you hadn’t considered it, is legislative requirements regarding an odometer, whether or not the dash has that functionality and whether or not it meets any legal requirements there might be.
on April 10th, 2014 at 7:26 am
Yeah, not sure what to do about an odometer. Does anyone know of a standalone, small odometer that can be triggered by a pulse?
on May 7th, 2014 at 8:29 pm
Looks like MoTeC dash has an odometer as standard.
Have found my fuel consumption and trip computer – looks great – http://www.ebay.com.au/itm/ONBOARD-COMPUTER-WITH-OLED-DISPLAY-USB-mpg-fuel-gauge-meter-and-more-/301169515545?pt=Motors_Car_Truck_Parts_Accessories&hash=item461f1a1c19