Gen2 Prius: Custom PIDs for Torque (Android App) with formulas

Hi USB,

Do you know the difference between ELM327 and PLX Bluetooth ?

Or Does PLX support CAN BUS protocal?

CWA

 

Many thanks USB for swift response. I will try to get PLX . My car does not responding to normal OBD2 as it is a JDM (prius 2008) model. I was told that CAN BUS will work on this JDM model.

 

Hi USB,

Finally I placed an order for plx Wiki BT unit. I am also expecting Galaxy tab.

Would you share the latest csv file for custom PIDs and (and the exact location to be copied) so that I can have a quick start?

Regards

CWA

 

I downloaded the latest CSV, but the latest version of torque (1.5.11 i believe) does not seem to use the .torque directory for the csv file. Do you know where it does look?

David

P.S. I found the problem was I had been using the FREE version of Torque. I paid the 4.95 and now works as shown.

 

usb,
Thanks for your fantastic work on the Torque .csv. I have been modifying it to fit my preferred units (kW) and I have a few questions about it:

Where did you get your data? xGauge? A manual? Days spent with CAN?

Where is the "Brake - Friction Pad Torque (lbs-ft)" measured? Is it at MG2, the wheels, or somewhere else?

I am trying to display friction brakes in kW but aren't sure about my multiplier. My current formula is Friction (kW) = (((256 * A) + B) - 16383) * ((4*R - 512) + (4*E)) / 5335 but if the torque is measured somewhere other than MG2 I am off by at least a 4.113 gear ratio.

 

Thanks for confirming my assumption and checking my numbers. 5335 was a mistake; the correct value to divide by is 9549 for output in kW. For hp the denominator is 5252 / 0.7376 = 7120.

Friction Brake Power (kW) = (((256 * A) + B) - 16383) * ((4*R - 512) + (4*E)) / 9549
Friction Brake Power (hp) = (((256 * A) + B) - 16383) * ((4*R - 512) + (4*E)) / 7120

I also found that using the individual battery cell voltages and the battery current gives both higher resolution and more stable numbers for HV battery pack output than the reported HV resource. The downside is that it uses a different ModeAndPID so I can't combine it with engine and motor numbers to determine losses in a single gauge in Torque. The formula I use is:
ModeAndPID 21CE
Header 7E3
Battery power (kW) = 0.001 * ((2.56 * B) + (0.01 * C) - 327.68) * ((2.56 * (D + F + H + J + L + N + P + R + T + V + X + Z + AB + AD)) + (0.01 * (E + G + I + K + M + O + Q + S + U + W + Y + AA + AC + AE)) - 4587.52)

Battery Power (hp) = ((2.56 * B) + (0.01 * C) - 327.68) * ((2.56 * (D + F + H + J + L + N + P + R + T + V + X + Z + AB + AD)) + (0.01 * (E + G + I + K + M + O + Q + S + U + W + Y + AA + AC + AE)) - 4587.52) * 0.001341

I came across a pretty interesting report on the 2004 Prius drivetrain by Oak Ridge National Lab (ORNL). They disassembled a prius and bench-tested a bunch of the components individually. The report includes data on gear losses at various oil temperatures and speeds (Tables 3.7-13), motor efficiency contours (Figures 3.18-20), lots of curves, and tons of pictures. It may help you answer your question about where the missing energy on your Torque display is going.

The report is titled "Evaluation of 2004 Toyota Prius
Hybrid Electric Drive System". It can be found here:
www.k0bg.com/images/pdf/890029.pdf

 

At the moment I am running Torque on my android phone, a HTC EVO. The 4.3" screen is mounted on a bendable stalk that is attached to the little triangular window just forward of the driver. If I get around to it I would like to end up permanently installing my old phone, a HTC Hero, somewhere below the speedometer but close to driving line-of-sight.

The gauges I typically display are:
ICE Power, HSD Power, HV Power, HV SOC, Friction Brake Power, and Timing Advance
If you have any suggestions for other fun and useful gauges I’d love to hear them. I’m an engineer, an optimizing efficiency nut, and I could watch changing numbers all day.

My driving is broken down into three regimes: power, glide, and braking.
When operating under power I try to keep ICE Power between 15 and 20 kW (max engine efficiency). I regularly exceed this for on-ramps, big hills, and the like, but for most straight roadway driving I try to stay in that band. Once I reach my peak speed I start to glide, trying to keep ignition timing at 5 degrees (fuel cut) and power in and out of the batteries as close to zero as possible (thus minimizing round-trip battery and conversion losses). When braking I try to brake with enough foresight to keep the Friction Brake Power value close to or at zero until I get down to 7 mph. If I have enough room to brake softly I like to keep power into my batteries under 10 kW on the theory that this is gentler to the batteries (6 years 148,000 miles) and may have a higher round-trip efficiency.

My 65 mile round-trip commute is half highway and half high-speed secondary road with slight hills and unavoidable stoplights. I have a mile or two of low-speed roadway on each end to properly warm up the engine and cool down the cabin. My typical speeds are 65-70 mph on the highway and 55-65 on the secondary. Since I started using the strategy outlined above I have been able to get a multi-tank average of 56-58 mpg even with A/C in the evening commute. While far from what some have achieved this is significantly better than the 48-52 mpg I ran earlier this summer on the same commute with similar temperatures.

 

Thanks USB. I just got it. I also just downloaded the paid version and just about to put your PID file. Let you know the outcome.

Just a question, what is the fastest PID rate on your device? mine is 18 pid /s - which is not bad. I have disable the fast communication.

Regards

CWA

 

If you really keep the HV battery current null during glide then you will find the battery SOC filled up gradually since pulsing and braking both fill it up and eventually there will be no room to accept regen current. In most cases it's better and easier to just do the "no arrow" glide which does use a bit of current (3 ~ 7 amps depending on speed). This slowly bleeds the HV battery during glide to make room to accept charge from pulsing and braking.

 

I try to keep the current near zero on glide but I have found, as you said, that it is effectively impossible to keep it at zero. If I'm not paying much attention to the numbers on the highway-speed glide I tend to stabilize at either 2.4-3 kW out of the batteries or 1-1.5 kW in. If I am paying close attention to the gauge I can keep it to .5-1.5 kW out of the batteries but it is incredibly sensitive to accelerator petal position. Most of my time on the highway is spent between 63 and 68% SOC.

Although they are expected to be rainy, I'm going to log data for the next few commutes so I can look at the histograms to get a better feel for how much of my drive I'm actually following my guidelines.