Can you actually drive with your engine off?

This is one of the recurring questions about hybrid cars.
Using Torque, I collected some data about my daily commute from home to work and back.
Here is one trip, from work to home.
Engine rpm are drawn in red: when the value is 0, the engine is off.
Veicle speed is blue: where speed is greater than 0 and the engine is off, we're moving with the electric motor.
With a little data processing, we can draw a graph to show when the car is moving regardless of which engine is using (gasoline or electric), and when is moving with 0 RPM:
Engine is off 55% of the time.
By comparison, in the trip from home to work, the engine is off 46% of the time.
On the average, in my daily trips, the engine is off 50% of the time.

There's a thread about this on the Hybrid Synergy Forum.

Speeding up Torque connection

At connection time, Torque probes the bluetooth adapter for supported protocols.
You can speed up the discovery process by setting the OBD protocol in the veicle profile.
For Yaris Hybrid, the protocol is:



Battery gain on slopes

Some more experiments with Torque:
How much charge can you gain driving down a slope?
Here is the data from a downhill road: the road is 1.4km long, I drove it entirely with the engine off, with the D gear, with only a slight braking, trying to keep the speed under 45 km/h
The blue line is the GPS altitude.
The red line is the battery % charge level.
Battery starts at 54.9 % at 238.5 meters.
At the end of the road, altitude is 159 m and battery is at 69.01%.
So a 79m height difference caused a 14% gain on battery level.

There's another interesting fact: SOC level seems to increase exponentially until it reaches 60%: from there on, even if the road became steeper (and thus leading to higher charging rate) the charging increases linearly.

There's a thread about this on the Hybrid Synergy Forum.

Using Torque with the Yaris Hybrid

Being a geek inside, I just feel uncomfortable without some kind of a "perfmon" of a given system.
The Yaris Hybrid, with its HSD engine, is an interesting system that deserve to be observed.
Modern (2001+) cars, have a data bus where performance data are collected and broadcasted for diagnostic purposes.
This bus (the CAN bus) can be accessed through an ODB-II port.
To collect and display these data you'll need:
  • an android phone
  • an OBD-II bluetooth adapter
  • Torque, an android app that can collect, record and display engine data from the car data bus.

I bought this adapter from amazon .

The OBD-II connector is located under the steering wheel, near the motor hood knob.

I plugged the adapter into the OBD-II port

I paired the adapter with the phone using bluetooth.

PriusChat has a thread about the PIDs needed to collect data from an HSD3 engine: http://priuschat.com/threads/geniii-prius-custom-pids-for-torque-app.98693/
Download the Prius3 PIDs .csv file
Put the .csv file into the .torque/extendedpids directory on your android phone.
Run Torque and select:
Settings / Manage extra PIDs / Add predefined set
Select the .csv filename you just copied.

Now, with the engine on, data begins to flow on the "Realtime Information" Torque screen:

Seeing data in realtime is fun, but the real game is collecting it for offline study.

To configure logging, go into the settings menu:

Settings / Data Logging & Upload / Select what to log
and add some PIDs like
  • Engine RPM
  • State of Charge
  • Batt Pack Current Val

Note: you'll have to scroll down to the Trip Recording section and check "Also log selected sensors". If this option is not selected, the log file will contain only GPS data and no engine data.

You can start and stop logging from the Realtime Information screen, using the menu.

Once you have collected a trip log, you can view it from the "Map View" screen.


Google advertising is way off the spot

Google is indeed really good at tracking my interests: every site I visit has an advertising about Toyota hybrids.
Ok google, you're right, I like Toyota hybrid cars, but see, I already own one and I'm not going to buy another anytime soon: so where is the "already purchased" button? Just show me other ads...


Mileage improvements

My Yaris Hybrid has reached 5000km and it's beginning to show mileage improvements: last October, when it was brand new, my daily commute was ranked 4.4 l/100km.
Now, with the temperature range comparable to that of October, I see a 4.2 l/100km.


A trip by the sea, Reloaded

Some months ago, I've tested the Yaris on a highway trip.
I had the chance to drive the same trip again.
The car now has 5000 km under its wheels, and consumption was 4.9 l/100km, a little better than last time.