SCR Catalyst Temperature Control for Neutral at Stop

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The interoperability and concurrent operation of selective catalytic reduction (SCR) exhaust aftertreatment and neutral at stop (NAS) systems in vehicles pose significant challenges, particularly in managing SCR catalyst temperature to optimize fuel economy and reduce emissions.

Innovation Solution

The implementation of an electronic control system that dynamically controls NAS capability based on SCR catalyst temperature, using a model to determine current and future temperatures and adjust NAS operation accordingly, enabling or disabling it to optimize thermal management and reduce fuel consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If NAS capability is continuously enabled to reduce fuel consumption, then fuel economy is improved, but SCR catalyst temperature may drop below required thresholds reducing aftertreatment effectiveness

Engineering Contradiction:

Improvefuel consumptionVSAvoidSCR catalyst temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The system dynamically adjusts NAS capability based on real-time SCR catalyst temperature conditions. The control system monitors temperature and enables or disables NAS capability accordingly, transitioning the system between different operational states to optimize both fuel economy and aftertreatment effectiveness.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system uses feedback from SCR catalyst temperature measurements to regulate NAS capability. Temperature data is fed back to the control system, which then adjusts NAS operation to maintain temperature within optimal ranges, creating a closed-loop control mechanism.

Inventive Principle:

Principle #23Feedback

2Reliability

If NAS capability is disabled to maintain SCR catalyst temperature, then aftertreatment effectiveness is preserved, but fuel consumption increases due to continued torque converter load

Engineering Contradiction:

Improveaftertreatment effectivenessVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system changes the operational parameter of NAS capability (enabled/disabled state) in response to SCR catalyst temperature conditions. This parameter change allows the system to adapt to varying thermal conditions and optimize the trade-off between fuel consumption and aftertreatment effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If SCR aftertreatment and NAS systems operate concurrently without coordination, then both systems can function independently, but system complexity and control difficulty increase

Engineering Contradiction:

Improvesystem independenceVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system merges the control logic for SCR aftertreatment and NAS systems into a unified control framework. By integrating temperature monitoring and NAS capability management into a single coordinated system, the patent reduces overall system complexity while maintaining the functional capabilities of both subsystems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control system performs multiple functions: it monitors SCR catalyst temperature, determines NAS capability status, and coordinates between aftertreatment and fuel economy objectives. This multi-functional approach consolidates control responsibilities and simplifies the overall system architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11441468B2Controls for vehicle systems including SCR exhaust aftertreatment and neutral at stop capability

Publication Date: 2022.09.13 CUMMINS INC

AI summary

A vehicle system includes an engine, a transmission including a torque converter, a clutch configured to selectably couple and decouple the torque converter, and a gearset, a selective catalytic reduction (SCR) exhaust aftertreatment system. An electronic control system may be operatively coupled with the engine, the electronically controllable clutch, and the SCR exhaust aftertreatment system. The electronic control system is configured to evaluate whether an SCR catalyst temperature satisfies at least one minimum temperature criterion, in response to the SCR catalyst temperature satisfying the minimum temperature criterion, permit a neutral at stop operation wherein the electronically controllable clutch is controlled to selectably decouple the torque converter and the one or more gears at least in part in response to the vehicle system being in a stopped state, and in response to the SCR catalyst temperature not satisfying the minimum temperature criterion, prevent the neutral at stop operation.