Internal Combustion Engine Catalytic Converter Warm-Up Control
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Solution Overview
Problem
Internal combustion engines face challenges in reducing toxic emissions during cold starts and minimizing the warm-up period of the catalytic converter, while also maintaining efficiency and reducing fuel consumption.
Innovation Solution
The internal combustion engine is configured to operate in a catalytic converter warm-up mode, where each combustion chamber follows a 720 crank angle degrees cycle with specific valve opening and closing timings, and internal exhaust gas recirculation is used to mix fuel and exhaust gas in the intake manifold, optimizing thermal efficiency and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If electric heating coils or smaller catalytic converter are used to reduce warm-up period, then catalytic converter warm-up time is reduced, but device complexity and cost increase
Solution Approach 1:
The exhaust gas itself is used to heat the catalytic converter through internal recirculation, making the system self-heating without external auxiliary equipment. The hot exhaust gases are redirected through the catalytic converter during cold start, using the engine's own waste heat to reach operating temperature.
Solution Approach 2:
A recirculation path acts as an intermediary mechanism to redirect exhaust gases through the catalytic converter. This intermediate flow path enables heat transfer from exhaust gases to the catalytic converter, facilitating warm-up without direct contact or external heating devices.
2Object-generated harmful factors
If conventional valve timing is used, then engine operation is simple, but toxic emissions increase during cold starts
Solution Approach 1:
The valve timing is made dynamic and adaptive, changing based on operating conditions. During cold start, the intake valve closes later and opens earlier to create specific pressure conditions that promote exhaust gas recirculation and reduce emissions. The control system adjusts valve events in real-time based on temperature and load sensors.
Solution Approach 2:
The valve timing parameters are modified during cold start operation. The intake valve closing timing is delayed and opening timing is advanced compared to normal operation, creating specific pressure differential parameters that facilitate exhaust gas recirculation and reduce toxic emissions during the warm-up period.
3Object-generated harmful factors
If exhaust gas is recirculated to reduce unburnt fuel, then emissions are reduced, but heat losses increase
Solution Approach 1:
The exhaust gas recirculation is applied locally and selectively during specific operating conditions (cold start) rather than continuously. The system identifies when the catalytic converter needs warming and activates recirculation only during that period, avoiding unnecessary heat losses during normal operation when the converter is already at operating temperature.
Solution Approach 2:
The exhaust gas recirculation operates periodically based on catalytic converter temperature conditions. The control system monitors temperature and activates recirculation in periodic intervals during cold start, then deactivates it once the converter reaches operating temperature, creating a periodic on/off pattern that balances emission control with heat preservation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces raw emissions during cold starts, shortens the catalytic converter warm-up period, decreases heat losses, and achieves more stable ignition from cycle to cycle, while also reducing fuel consumption.
Implementation Method 1
mix fuel and exhaust gas in the intake manifold
Implementation Method 2
exhaust gas is forced into the intake manifold by means of the piston
Implementation Method 3
the catalytic converter cannot fully convert the toxic emissions into less toxic substances
Implementation Method 4
convert the toxic emissions into less toxic substances
Implementation Method 5
The heat and energy released by the burning of the air-fuel mixture causes a further rise in pressure in the combustion chamber
Implementation Method 6
The heat and energy released by the burning of the air-fuel mixture causes a further rise in pressure in the combustion chamber which is used to do work against a movable wall of the combustion chamber
Data Source
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AI summary
The invention relates to an internal combustion engine comprising a set of combustion chambers, each combustion chamber (2) being provided with a controllable intake valve (7) configured for opening and closing an intake port (8), a controllable exhaust valve (9) configured for opening and closing an exhaust port (10), a piston (5) displaceable back and forth in said combustion chamber (2) between a top dead center (TDC) and a bottom dead center (BDC), and a fuel injector (16). The internal combustion engine (1) further comprising an intake manifold (12) connected to the intake port (8) of each combustion chamber of said set of combustion chambers. The internal combustion engine (1) is configured to be operated in a catalytic converter warm-up mode, wherein each combustion chamber (2) is configured to be driven in four-stroke operation comprising a 720 crank angle degrees cycle, and is configured to open the intake port (8), the intake port (8) starting to open in the range 90 to 180 CAD, and close the intake port (8), the intake port (8) becomes fully closed in the range 180 to 270 CAD, open the exhaust port (10) during the power stroke, the exhaust port (10) starting to open in the range 405 to 495 CAD, open the intake port (8) during the exhaust stroke, the intake port (8) starting to open in the range 610 to 690 CAD, and close the exhaust port (10) during the exhaust stroke, the exhaust port (10) becomes fully closed in the range 630 to 710 CAD, wherein the exhaust gas is forced into the intake manifold (12) by means of the piston (5), mix fuel and exhaust gas in the intake manifold (12), and close the intake port (8), the intake port (8) becomes fully closed in the range 700 to 720+20 CAD.