An Ignition controller for gasoline spark ignition engines.
Currently it supports the Ford EEC-IV Thin Film Integration module as a decoder and ignitor, using the STM32F4-Discovery Cortex-M4 Board from ST, and a TLC2543 ADC from TI. It should be fairly generic to any engine, with any number of ignition outputs, if a decoder is written.
EEE-IV TFI modules came in a few flavors. Currently only the Grey(Pushstart) mounted-on-distributor varient is supported. This module controls dwell based on RPM, and allows ECM timing control via the SPOUT signal. The module outputs a PIP signal, which is a clean filtered 50% duty cycle square wave formed from a rotating vane and hall effect sensor inside the distributor. Without a SPOUT signal from the ECM, the module will fall-back on firing the coil on the rising edge of PIP, which will still drive the engine in fixed-timing, fixed-dwell mode.
This controller uses PIP to determine engine speed, and will rise SPOUT at an appropriate time to control timing based on a engine inputs
Since dwell is controlled by TFI itself, there is no use for measuring battery voltage. Spark advance is determined by a MAP/RPM table lookup.
The decoder currently measures RPM by using the last two trigger times, creating
an average over 180 degrees of crank rotation. Trigger-to-trigger variation
allowance in rpm is controlled by config.decoder.max_variation.
Static configuration is in config.c. The main configuration structure is
config, along with any custom table declarations, such as the provided example
timing_vs_rpm_and_map. Pin configurations are platform specific and are
documented in the platform source.
| Member | Meaning |
|---|---|
num_events |
Number of configured events |
events |
Array of configured event structures, see Event Configuration below |
decoder.type |
Decoder type. Possible values in decoder.h |
decoder.offset |
Degrees between 'decoder' top-dead-center and 'crank' top-dead-center. TFI units by default emit the falling-edge trigger 45 degrees before they would trigger spark in failsafe mode |
decoder.trigger_max_rpm_change |
Percentage of rpm change between trigger events. 1.00 would mean the engine speed can double or halve between triggers without sync loss. |
decoder.trigger_min_rpm |
Minimum RPM for sync. Should be just below the slowest cranking speed. |
decoder.t0_pin |
PORTB Pin for primary trigger |
decoder.t0_edge |
Edge to trigger on for primary trigger |
decoder.t1_pin |
PORTB Pin for secondary trigger |
decoder.t1_edge |
Edge to trigger on for secondary trigger |
sensors |
Array of configured analog sensors. See Sensor Configuration below. |
timing |
Points to table to do MAP/RPM lookup on for timing advance. |
ve |
Points to table for volumetric efficiency lookups |
commanded_lambda |
Points to table containing target lambda |
injector_pw_compensation |
Points to table containing Voltage vs dead time |
rpm_stop |
Stop event scheduling above this RPM (rev limiter) |
rpm_start |
Resume event scheduling when speed falls to this RPM (rev limiter) |
Event configuration is done with an array of schedulable events. This entire
array is rescheduled at each trigger decode, allowing any angles (0-719) to be
used for events, as long as a trigger event occurs between any two fires of a
given event (e.g. for FORD_TFI, for 8 events, as long as the decoder fires
twice in 720 degrees, which of course it does). Currently there are three types
of event:
| Event | Meaning |
|---|---|
IGNITION_EVENT |
Represents spark ignition event. Will start earlier than specified angle because of dwell, will stop at the angle specified minus any advance. |
FUEL_EVENT |
Represents fuel injection event. Not currently implemented. |
ADC_EVENT |
Initiates sensor data gathering event. Sensor data |
| is often only useful at certain parts of the engine cycle. |
The event structure has these fields:
| Member | Meaning |
|---|---|
type |
Event type from above |
angle |
Base angle for an event |
output_id |
PORTD pin to use for this output |
inverted |
Set to one if active-low |
Sensor inputs are controlled by the sensors config structure member, and is an
array of configured inputs. The indexes into the array for various sensors are
hardcoded, use the provided enums to reference the sensors. Each sensor entry
is a structure describing what pin to use, and how to translate the raw sensor
value into a usable number:
| Member | Meaning |
|---|---|
pin |
pin to use on TLC2543 |
method |
Processing method, currently supported are linear interpolation, table looksup, and thermistors |
source |
Type of sensor, currently supported are analog and frequency based. |
params |
Union used to configure a sensor. Contains range used for calculated sensors, and table for table lookup sensors. |
lag |
Lag filtering value. 0 means no filtering, 100 will effectively never change. |
params.range.min |
For processing, value that lowest raw sensor value reflects |
params.range.max |
For processing, value that highest raw sensor value reflects |
params.therm |
For processing, Bias resistor and A, B and C parameters of the Steinart-Hart equation |
fault_config.min |
Raw sensor value, below this indicates sensor fault |
fault_config.max |
Raw sensor value, above this indicates sensor fault |
fault_config.fault_value |
During sensor fault, use this fallback value |
For method SENSOR_LINEAR, the processed value is linear interpolated based on
the raw value between min and max (with the raw value being 0 - 4096).
Frequency sensors measure a raw value between 0 - 20000 Hz.
The onboard ADC is not used. Instead a TLC2543 external ADC should be connected to SPI2 (PB12-PB15). Currently the first 10 inputs are supported.
Tables can be up to 24x24 float values that are bilinearly interpolated. Use
struct table to define a table, with the following relevent fields:
| Member | Meaning |
|---|---|
title |
Table title |
num_axis |
1 or 2, for 1d vs 2d lookup |
axis[0] |
Only axis if 1d table, horizontal axis if 2d. |
axis[1] |
Vertical axis for 2d table. |
axis[?].name |
Axis Title |
axis[?].num |
Number of columns/rows in the axis |
axis[?].values |
Value for each column in the axis |
data.one |
Array of data points for 1d table |
data.two |
2d array for 2d table. First index represents vertical axis. |
For a new table to be configurable over the serial console, it must be declared
externally such that it can be directly referenced in console.c.
The serial console immediately outputs csv lines with a default set of values.
This set of values, along with any other configurable, can get viewed or changed
by commands and responses. All commands are processed after a newline, and the
result with start with a *, distinguishing it from normal log output.
Any configuration node may support the command list, get, or set. Toplevel
nodes are config and status. The hierarchy of config nodes can be traversed
by using list, and then any commands on the results.
A few specific example nodes:
| Node | Meaning |
|---|---|
config |
Top-level configuration |
status |
Real-time status output |
config.tables.timing |
Timing table |
config.sensors.iat |
IAT sensor |
config.feed |
comma-delimited list of config nodes to output |
flash |
Set to save current configuration |
Any config node that is a simple value (string, float, int) can be used with
config.feed. Some config nodes are detailed. On get they will return a
space-delimited list of =-delimited key-value pairs. Any pair returned can
then be set on the node. For example
get config.tables.timing
* Name=test num_axis=2 rows=3 ...
get config.events 0
* type=fuel angle=0 output=3 inverted=0
set config.events 2 inverted=1
Tables will treat any key that is in the form of [row][col] as a value to be
returned or set
get config.tables.timing [2][2]
set config.tables.timing name=Timing [2][2]=5.2
Requires:
- Complete arm toolchain with hardware fpu support.
- BSD Make (bmake or pmake)
- check (for unit tests)
cd libopencm3
make
cd ../src/
make clean
make PLATFORM=stm32f4-discovery
tfi is the resultant executable that can be loaded.
To run the unit tests:
cd src/
make clean
make check