Aftertreatment Heat-Up via Motor Generator Loading
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Solution Overview
Problem
Current automated mechanical transmission systems in vehicles take an inefficiently long time to heat up the exhaust aftertreatment system to achieve optimal NOx conversion temperatures, leading to prolonged inefficient engine operation.
Innovation Solution
A transmission system with a motor generator coupled to the countershaft, controlled to direct power to the motor generator during engine startup, operating in aftertreatment heat-up mode, which includes running the engine in cylinder deactivation mode and using non-optimized gear ratios to quickly elevate the aftertreatment system temperature, thereby reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operates at low load (brake mean effective pressure between three and four bar), then fuel economy is improved, but the aftertreatment system takes too long to heat up to optimal temperature
Solution Approach 1:
The system applies preliminary action by directing power to the motor generator during engine startup to pre-heat the aftertreatment system before normal operation begins. This ensures the aftertreatment reaches optimal temperature faster, resolving the contradiction between fuel economy and heat-up time by preparing the system in advance.
Solution Approach 2:
The system dynamically adjusts engine operation by switching between different modes: at low brake mean effective pressure (three to four bar), it directs power to the motor generator for fast heat-up; at higher loads, it operates in cylinder deactivation mode for fuel efficiency. This dynamic adaptation resolves the contradiction by optimizing for the appropriate parameter based on operating conditions.
2Temperature
If the engine runs in cylinder deactivation mode to increase load for fast heat-up, then aftertreatment temperature increases, but fuel economy decreases
Solution Approach 1:
The system dynamically switches between cylinder deactivation mode (for fuel efficiency at normal operation) and full cylinder operation with motor generator loading (for fast heat-up when needed). This dynamic mode switching resolves the contradiction by applying high-load operation only when temperature increase is required, rather than continuously.
Solution Approach 2:
The system uses periodic action by applying high-load cylinder operation intermittently during startup phases to heat up the aftertreatment, then transitioning to efficient cylinder deactivation mode for sustained operation. This periodic application of high load resolves the contradiction by limiting fuel consumption penalties to only when temperature increase is necessary.
3Speed
If power is directed to the motor generator during startup, then the aftertreatment system heats up quickly within 50 seconds, but additional energy is consumed
Solution Approach 1:
The system performs preliminary action by directing power to the motor generator during the critical startup phase to quickly heat the aftertreatment system. This concentrated energy input during the essential warm-up period achieves fast heat-up (within 50 seconds) while limiting total energy consumption to only when it provides maximum benefit.
Solution Approach 2:
The motor generator serves dual purposes: it can act as a motor to drive the aftertreatment heat-up process, or as a generator to recover energy during braking. This self-service capability resolves the energy contradiction by allowing the system to invest energy when needed for fast heat-up while recovering energy during deceleration, netting reduced overall energy loss.
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
The system rapidly heats up the aftertreatment system to desired temperatures within 50 seconds of engine start, improving NOx conversion efficiency and reducing emissions, while also enhancing fuel economy by minimizing idle time and increasing enthalpy to the aftertreatment system.
Implementation Method 1
A motor generator can be selectively coupled to the countershaft... The controller directs power to the motor generator at startup during an aftertreatment heat-up mode
Implementation Method 2
an internal combustion engine arranged on a vehicle... increasing load on the internal combustion engine
Implementation Method 3
The aftertreatment system reduces emissions in an exhaust of the internal combustion engine... the aftertreatment system is heated up to an elevated temperature and emissions are thereby reduced based on the elevated temperature
Data Source
AI summary
A transmission system constructed in accordance to one example of the present disclosure includes an aftertreatment system and a controller. The transmission system is selectively coupled to an engine crankshaft of an internal combustion engine arranged on a vehicle. The aftertreatment system reduces emissions in an exhaust of the internal combustion engine. The controller operates in an aftertreatment heat-up mode such that the aftertreatment system is heated up to an elevated temperature and emissions are thereby reduced based on the elevated temperature. The controller operates in the aftertreatment heat-up mode when the internal combustion engine is operating at or below a brake mean effective pressure between three and four bar. The aftertreatment heat-up mode comprises increasing load on the internal combustion engine.