12. Parameter reference
#How to use this reference
The order follows the FuelTech Vision screens on the PC: the Adjust tab and the Settings tab.
On the phone, the tablet and the panels the same fields appear on flat pages, without the group titles, and Rail #2 has its own page.
Default is the value in the new map. The new map comes with the function off, feed-forward off, and target, Kp, Ki and G(W) at zero: the order of filling in is in Commissioning and tuning step by step.
Range is what the screen accepts. When the screen does not show the unit, the table says so.
Pressures are in bar (1 bar = 14.5 psi). Check the unit shown next to the field.
Target, guards, minimum pressure and cut limit are on the same basis as the reading of the DI Rail pressure #1 or DI Rail pressure #2 channel: the VCU neither adds nor subtracts atmospheric pressure.
The function comes off. Press and hold the High pressure fuel pump (HPFP) card in Other Functions (tablet and panels: Functions card over Other) and use On / Off.
Each parameter has a mark that tells when the change takes effect:
| Mark | When it takes effect |
|---|---|
| No mark | The VCU accepts it immediately, with FuelTech Vision connected. |
| (write) | Takes effect when the map is written to the VCU. |
| (write and restart) | Write the map and power-cycle the VCU (turn it off and back on). |
| Turning the function on or off | When the map is written, the VCU restarts by itself, with the engine stopped. |
#Adjust tab: pressure target map
The Adjust tab shows Fuel pressure target map (TPS) or (MAP), depending on the Fuel pressure target map field.
The map has up to 8 RPM columns by 8 load rows, and applies to both rails. The new map already comes 8 by 8, with all the target at 0 bar.
Each load axis has its own table in FuelTech Vision. Only the one for the chosen axis goes to the VCU, and one does not copy the other.
The axes must be increasing. Outside them the VCU does not extrapolate: the edge row or column applies.
Details in Pressure target.
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Columns (RPM) | 0 to 16000 rpm, step 500 | 0; 1000; 2000; 3000; 4000; 5000; 6000; 8000 | Speed axis. |
| Rows (TPS) | 0 to 100 %, step 0.1 | 0; 15; 30; 45; 60; 75; 90; 100 | Load by throttle position. |
| Rows (MAP) | −1 to 10 bar, step 0.01 | −0.5 to 3.0, in 0.5 steps | Load by the MAP channel, in gauge bar: vacuum is negative. |
| Cells (target) | 0 to 500 bar, step 0.1 | 0 in all | Pressure the VCU pursues in the rail. |
#General settings
#Target map and number of rails
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Fuel pressure target map (write) | TPS (%) or MAP (bar) | MAP | Chooses the load axis for the rows of the target map. Changing the axis requires writing the map. |
| Rails count (write and restart) | Single rail or Dual rail | Single rail | With Dual rail, Output (Rail #2) and the Rail #2 group appear. |
#Rail #1 and Rail #2
Each rail has its own group, with the same fields. Rail #2 appears only with Dual rail.
Details in Before you start: installation and The lobe angles.
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Output (Rail #1) and Output (Rail #2) (write and restart) | one blue, gray or yellow output | no output | Connects the rail valve to a VCU output. With no output the function does not start. |
| Output behavior (write and restart) | Normal or Inverted | Normal | Normal: the pump delivers with the valve energized. Inverted: it delivers with the valve off. |
| Rail pressure sensor reference (write and restart) | HP Rail #1 (DI1) or HP Rail #2 (DI2) | Rail #1: DI1. Rail #2: DI2. | Pressure sensor the rail uses. The sensor is set up in Sensors and calibration > DI rail pressure. |
| Feeds bank A / B / C | on or off, each one | off | Mark only direct injection banks, never the same one on both rails. It enters the feed-forward consumption and the injector cut. |
| Cam dependence | None, Intake #1, Intake #2, Exhaust #1 or Exhaust #2 | None | VVT camshaft that shifts the window. Only with VVT on and the cam sensor reading. Without VVT, leave it at None. |
| Number of lobes per cycle | 1 to 4 | 3 | Pump lobes on the camshaft that drives it. They are evenly spaced at 720 ÷ lobes, in crankshaft degrees. |
| Lobe #1 opening angle | 0.0 to 720.0 crankshaft degrees, step 0.1. The screen does not show the unit. | 60.0 | Earliest start the pulse can have. Together with the closing, it sets the window width. |
| Lobe #1 closing angle | 0.0 to 720.0 crankshaft degrees, step 0.1. The screen does not show the unit. | 180.0 | End of the pulse, near the lobe peak. The width is closing − opening. |
| Windows of the other lobes (calculated) | read only, appears with more than 1 lobe | calculated | Shows opening and closing of lobes 2 to N from lobe #1, without cam or delay. |
The width must be greater than 0 and less than 720 ÷ lobes. Outside that, the VCU turns the rail off, and FuelTech Vision shows an error in the map diagnostics list.
#PID settings
The PID settings page also gathers the feed-forward, the pump model and the trim. The fields apply to both rails.
Details in Closed loop and PID and Feed-forward (physical model) and trim.
#Feedforward (physical model)
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Enable feedforward (PID as trim) | on or off | off | On: the VCU calculates the pulse from the model and the PID only corrects. Off: the PID commands the whole pulse. |
| Injector rated flow | 0.0 to 10000.0 lb/h, step 0.1 | 0.0 | Flow of the installed injectors. The VCU scales the consumption by the ratio between this flow and the reference flow. |
| Injector rated flow preset reference | 0.0 to 10000.0 lb/h, step 0.1 | 0.0 | Flow of the injector with which the G(W) curve was measured. With either flow at 0 the ratio is 1. |
#Pump model
Pump model is only the title of this group on the PC. The screen has no list of pumps: all values come from calibration.
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Valve base dead time (t0) | 0.00 to 5.00 ms, step 0.01 | 1.50 | Valve dead time: the part of the pulse that delivers no volume. Added to the curve by battery voltage. |
| Leakage coefficient (beta) | 0.00 to 10.00, step 0.01. The screen does not show the unit. | 0.00 | Compensates for pump leakage: grows with the target and falls with rpm. Leave at 0 without a measurement. |
| Angled window upper limit | 10.0 to 180.0°, crankshaft degrees, step 0.1 | 60.0 | Maximum pulse duration, counting dead time. The smaller of it and the window width applies. |
| Valve delay (phase advance) | 0.00 to 5.00 ms, step 0.01 | 0.00 | Advances the whole pulse by 0.006 × rpm × delay, in crankshaft degrees. It does not change the duration. |
#PID (shared between the rails)
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Derivative gain | 0 to 10000, step 0.001. The screen does not show the unit. | 0 | A single Kd for both rails. Kp and Ki are curves by rpm, in the curves section. |
#Transient and trim
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Fuel enrichment gain (kick) | 0.000 to 0.200, step 0.001. The screen does not show the unit. | 0.030 | Short boost when injector consumption rises fast. It only adds to the pulse. |
| Kick upper limit | 0.00 to 5.00 ms, step 0.01 | 1.50 | Limit of the kick boost. |
| Pressurization gain (ms/(bar/s)) | 0.0000 to 0.0100 ms per (bar/s), step 0.0001 | 0.0030 | Adds time when the target rises and removes it when the target falls, limited to ±1.5 ms. |
| PID minimum trim | −10.00 to 0.00 ms, step 0.01 | −2.00 | Lower limit of the PID correction. The floor is the larger, in absolute value, of this and the Trim floor: feedforward fraction times the feed-forward. |
| PID maximum trim | 0.00 to 10.00 ms, step 0.01 | 2.00 | Upper limit of the PID correction. |
| Trim floor: feedforward fraction | 0 to 100 %, step 1 | 50 | Floor of the correction as a % of the feed-forward. With 0 % only the PID minimum trim applies. |
| Anti-windup (integrator clamp) | 0 to 1000, step 1. The screen does not show the unit. | 50 | Limits the integral accumulator, in bar × s: the maximum integral part is Ki × Anti-windup, in ms. Not used without feed-forward. |
#Protection settings
#Engine start
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Crank out RPM (write) | 200 to 1000 rpm, step 10. The screen does not show the unit. | 400 | Below it the valve is held on during start, until the timeout. The start ends only with rpm equal to or above it. |
| Engine running RPM (disengages lockout) (write) | 400 to 1500 rpm, step 10. The screen does not show the unit. | 700 | Above it the injector lockout of the start is released. The lockout only applies with the cut on in the rail. |
| Minimum rail pressure for injection | 3.0 to 50.0 bar, step 0.5 | 12.0 | Releases the injector lockout and may end the start routine. With the low pressure cut on, the injectors wait for limit + 2 bar. |
| Lockout timeout (from start of cranking) | 1.0 to 10.0 s, step 0.1 | 5.0 | Maximum time of the injector lockout and of the valve held on, counted from engine sync. |
#Low rail pressure injector cut-off
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Injector cut-off rail pressure limit | 0.0 to 500.0 bar, step 0.1 | 30.0 | Below it the injectors get no pulse and return above limit + 2 bar (32 bar at the default). Leave it below the cranking pressure and the lowest target. |
| Enable on Rail #1 and Enable on Rail #2 | on or off, per rail | off | Turns the cut on in the rail, in the checked banks. It is the only switch for the cut and the start lockout. |
On the phone the name is Enable low-pressure injector cut-off (Rail #1), and the same for Rail #2.
#Protections (guards)
Before the first start, set the three levels below the full scale of your sensor, with the release lower than the latch: see step 2 of Commissioning and tuning step by step. The defaults (180, 190 and 184 bar) only act with a sensor whose full scale is above them (except Guard 2 by the target plus 20 bar condition, with the release below full scale).
Guard 2 also turns the pump off with the pressure more than 20 bar above the target, without falling, for 300 ms in a row (conditions in Cranking and protections). This value is fixed.
Details in Cranking and protections.
| Parameter | Range and unit | Default | Effect |
|---|---|---|---|
| Guard 1: entry-level | 0.0 to 500.0 bar, step 0.5 | 180.0 | Above this level the pulse is limited to the Guard 1 ceiling. It exits 3 bar below. |
| Guard 1: Active command upper limit | 0 to 100 %, step 1 | 50 | Pulse ceiling with Guard 1 active, as a % of the window width. With feed-forward, it only limits if % × width is below the Angled window upper limit. |
| Guard 2: latch level | 0.0 to 500.0 bar, step 0.5 | 190.0 | Above it for about 150 ms in a row the VCU turns off the rail pump. It cuts only the pump, never the injectors. |
| Guard 2: release level (hysteresis) | 0.0 to 500.0 bar, step 0.5 | 184.0 | The pump returns only when the pressure falls below this level. Leave it below the latch; the default is 6 bar below. |
#Curves and graphs
Five graph pages come after the protections, each with the graph and the table of points. They apply to both rails.
Between points the VCU interpolates in a straight line. Outside the first and last point it holds the value of the end.
| Parameter | Size and range | Default | Effect |
|---|---|---|---|
| Proportional gain Kp (RPM): axis | 8 points, RPM from 0 to 16000, step 50 | 800; 1500; 2500; 3500; 4250; 5000; 6000; 7500 | Speeds at which Kp is defined. |
| Proportional gain Kp (RPM): data | 0 to 10000, step 0.001. The screen does not show the unit. | 0 in all | Kp at each rpm. Unit: see PID (shared between the rails). |
| Integral gain Ki (RPM): axis | 8 points, RPM from 0 to 16000, step 50 | 800; 1500; 2500; 3500; 4250; 5000; 6000; 7500 | Speeds at which Ki is defined. |
| Integral gain Ki (RPM): data | 0 to 10000, step 0.001. The screen does not show the unit. | 0 in all | Ki at each rpm. Unit: see PID (shared between the rails). |
| Capture curve G(W): axis W (demand) | 8 points, W from 0 to 20, step 0.01. The screen does not show the unit. | 0.5; 1.5; 3.0; 4.5; 5.0; 5.5; 6.6; 8.4 | W is the injector consumption in ms, corrected to 100 bar. |
| Capture curve G(W): data | 0 to 180°, crankshaft degrees, step 0.1 | 0 in all | Crankshaft degrees of useful pulse to deliver the demand W. Zeroed curve: the model delivers no volume. |
| Battery voltage based dead time: axis Betery voltage (battery voltage; the screen spells it this way) | 6 points, 0 to 30 V, step 0.001 | 6; 8; 10; 12; 14; 16 V | Voltages at which the correction is defined. |
| Battery voltage based dead time: data | −5.00 to 5.00 ms, step 0.01 | 0 in all | Added to t0 according to the battery voltage. |
| Fill factor (RPM): axis | 8 points, RPM from 0 to 16000, step 500 | 1000; 2000; 3000; 3500; 4250; 5000; 6000; 7500 | Speeds at which the factor is defined. |
| Fill factor (RPM): data | 0.50 to 1.20, step 0.01. No unit. | 1.00 in all | Enters as a factor in the calculation of W, before the G(W) curve. With 1.00 there is no effect. Recommended practice: 1.00 until measured, and change it only if the PID trim shows a trend with rpm. |