Engine remapping
WHY ECU REMAPPING?
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Optimized powertrain calibrations are nowadays essentials by the need for lower emissions (NOx, HC, CO, Particulate Matter), better Fuel Economy and improved drive quality.
When a manufacturer develops a new car they have to take into consideration all of the conditions it may be subjected to, in all of the regions in which they intend to sell this model. This means instead of just optimizing the ECU’s program or ‘map’ to deliver the best performance or the most fuel efficiency, they have to make compromises to the map to take into account these potential differing operating conditions. These could include sub-standard fuels, extremes in temperature and altitude, differing emission laws and even the possibility that vehicle may not be serviced on a regular basis and in accordance with the manufacturers recommended intervals.
ECU remapping (ECU tuning) is taking a read from the ECU’s processing chip of the vehicles standard maps and adjusting various parameters within the maps such as fuel pressure, boost pressure (on turbocharged applications) ignition advance and throttle pedal control amongst others to release the true performance (torque&power, fuel economy) from the engine. It is a completely safe process as it is just giving the engine the performance it should have had in the first place before all the compromises were applied to the original programming. Every engine will have its own unique maps and by adjusting these we can fine tune the characteristics of the engine.
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ENGINE CALIBRATION STRATEGIES
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Many strategies actually exist to improve the performance of the engine giving an advantage on torque&power, fuel economy, throttle response or all of them together. We can have a look at some of them:
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Start of injection (SOI)
Start of injection in modern diesel engines or spark advance in petrol engines is one of the main strategies used to deliver more torque/power and provide a better fuel economy. Injecting fuel earlier in the combustion chamber gives the time to the fuel to atomize better and mix with the air, releasing already some energy in the early stages of the combustion process. Fuel is injected earlier in the combustion chamber either to increase the cylinder work or to minimize the fuel used for that specific torque&power requested from the driver through the accelerator. This gives the possibility to optimize the fuel economy in part load operation and increase the performance when the driver needs it.
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Rail pressure
The increase in rail pressure is one of the common strategies used to increase the efficiency of the engine (hence burning less fuel) in part load operations and to give more torque&power if the driver wants it. In part load operations in fact, due to the increased injection pressure, the injection rate increases and therefore the fuel is burned earlier and faster (more efficiently). Increasing the rail pressure at high loads will favor also an increase of the injection rate, hence the possibility to use more air and consequently the engine can deliver more torque&power.
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Valve timing & lift
Valve timings govern the opening and closing of the intake and exhaust valves and how effectively the engine is "breathing". Variable Valve Timing (VVT) was then introduced to spread the engine performance & fuel economy in most of the operating condition (high/low load and high/low rpm). For example, a fixed early closure of the intake valve helps the engine at low revs trapping the air change inside the cylinder but it throttles the air flow at high rpm, limiting the max power the engine can achieve. Common strategy to increase the engine responsiveness at low rpm and torque is by using the so called valve overlap: a late intake valve closure and early exhaust valve opening will favor a fresh air mass flow through the cylinder that goes straight into the turbine inlet, spinning it faster and increasing the boost level hence torque&power.
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To mention some of the other strategies are
Boost level
Injection quantities
Injection rate shaping
Exhaust Gas Recirculation (EGR)
According to the engine specifications and fuel used, we are able to optimize all these strategies and generate
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You can find the description and relative quotes of each of those remappings in the next sections as well as the procedure we are going to follow with your vehicle.
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