Hybrid Vehicle Catalyst Warm-Up Torque Control
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Solution Overview
Problem
Existing control systems for hybrid vehicles face challenges in reducing engine torque changes when warming up the exhaust gas purification catalyst, which can lead to unstable vehicle behavior and potential thermal damage to the catalyst.
Innovation Solution
A control system for hybrid vehicles that includes a controller to determine the need for catalyst warming, disengaging the clutch to disconnect the first motor from the engine, and retarding the ignition timing of the engine to raise the catalyst temperature without significantly changing engine torque, thereby preventing inertial load-induced torque changes and thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the ignition timing is retarded to warm up the catalyst, then the catalyst temperature is raised promptly, but the engine torque changes significantly causing unstable vehicle behavior
Solution Approach 1:
The first motor is disconnected from the engine through clutch disengagement during catalyst warm-up. This extraction removes the source of inertial load that would otherwise cause engine torque changes when ignition timing is retarded, allowing stable vehicle behavior while still warming the catalyst effectively
Solution Approach 2:
The system changes the operational state of the clutch (engaged/disengaged) based on whether catalyst warm-up is required. By disengaging the clutch during warm-up, the first motor is isolated from the engine, preventing torque fluctuations while maintaining the ability to connect them during normal operation
2Productivity
If the first motor is connected to the engine through the clutch during catalyst warm-up, then the hybrid vehicle can operate in normal propulsion mode, but the inertial load of the first motor causes significant engine torque changes
Solution Approach 1:
The clutch engagement state is dynamically adjusted based on operating conditions. During catalyst warm-up, the clutch is disengaged to eliminate inertial load effects. During normal propulsion, the clutch is engaged to enable power transmission. This dynamic switching optimizes both torque stability and propulsion efficiency depending on the operational phase
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 solution effectively raises the catalyst temperature promptly while maintaining engine torque stability, preventing misfires and improving energy efficiency by disconnecting the first motor from the engine during ignition retard, thus stabilizing vehicle behavior and reducing fuel consumption.
Implementation Method 1
retard an ignition timing of the engine when it is necessary to warm the purifying device
Data Source
AI summary
A control system for a hybrid vehicle that reduces a change in an engine torque when warming a catalyst. The hybrid vehicle comprises a catalyst that purifies exhaust gas, a first motor, a differential mechanism having a plurality of rotary elements, and an engagement device that selectively connects the first motor to an engine. A controller is configured to determine whether it is necessary to warm the catalyst, and disengage the engagement device while retarding an ignition timing of the engine when it is necessary to warm the purifying device.