The DPF software can be divided into three separate control software modules: the DPF control module, the DPF fuel flow control module, and the DPF air flow control module.
These three modules are controlled by a fourth software module, which is called the DPF matching module. The matching module controls the operation of other modules when an active regeneration is requested. The DPF control module is a subsystem of the DPF matching module.
DPF Fuel Control Module
The DPF fuel management module controls the following functions:
- Synchronization of four separate injections per working stroke and the amount of fuel injected (preliminary, main and two additional injections).
- Injection pressure and switching between three different levels of injection calibration.
The above functions depend on the condition of the catalytic converter and DPF.
In addition to measuring catalyst activity and DPF, controlled injection determines the required injection level. The fuel management system calculates the amount of fuel and the timing of four separate injections for each of the three levels of injection pressure calibration, and controls the switching between levels.
Two additional injections are required to separate the functions of increasing the temperature of the gases in the cylinder and producing hydrocarbons. The first post-injection is used to generate a higher temperature of the gases in the cylinders at the same time as maintaining the same engine torque as in normal (not during regeneration) engine operation. The second post-injection is used to generate hydrocarbons by directing unburned fuel to the catalytic converter without increasing engine torque.
DPF air flow control module
The DPF air flow control module controls the following functions:
- EGR control system
- boost pressure control system
- Intake air temperature and pressure control system
During active regeneration, the EGR is turned off and the boost pressure regulator closed-loop activation is calculated. The air flow control module monitors the air pressure and temperature levels in the intake manifold. This control is necessary to achieve the correct conditions inside the cylinder for stable and reliable combustion of the additionally injected fuel.
The module controls the intake air temperature by actuating the EGR throttle and adjusting the boost pressure.
DPF matching module
The DPF Coordinating Module, upon receiving a regeneration request from the control module, initiates and coordinates the following DPF regeneration requests:
- Disable EGR
- Boost pressure control
- Increased engine load
- Manifold air pressure and temperature control
- Fuel injection control
When the control module issues a regeneration request, the coordinating module requests EGR shutdown and boost pressure required for regeneration. It then waits for a feedback signal from the EGR system confirming that the EGR valve is closed.
When the EGR valve closes, the coordinating module initiates a request for an increase in engine load by controlling intake air temperature and pressure.
After receiving confirmation that intake conditions are under control or that the calibration time has elapsed, the matching module goes into a state of waiting for the driver to release the accelerator pedal. If this happens or the calibration time expires, the matching module generates a request for fuel injection control to increase the exhaust gas temperature.
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