Hybrid Engine Control for Catalytic Converter Activation

Solution Overview

Problem

In hybrid vehicles with variable valve operating mechanisms, starting the engine without an active catalytic converter leads to increased HC emissions, as combustion gases do not flow through the catalytic converter, preventing effective cleaning of exhaust gases.

Innovation Solution

An engine control apparatus with a conversion angle detecting device, angle determining device, and engine load calculating device is used to adjust the engine load based on the detected conversion angle, ensuring the catalytic converter is activated quickly by controlling the variable valve timing and engine operation to reduce HC emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the engine is started while the catalytic converter is not in an active state, then the vehicle can be started into motion, but HC emissions increase because combustion gas does not flow through the catalytic converter

Engineering Contradiction:

Improvevehicle starting capabilityVSAvoidHC emissions

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary action by detecting the catalytic converter's activation state before engine start and adjusting the variable valve operating mechanism's conversion angle to an appropriate starting conversion angle in advance. This ensures that when the engine starts, the valve timing is optimized to direct combustion gas through the catalytic converter, enabling it to warm up and activate quickly while still allowing vehicle motion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the conversion angle parameter of the variable valve operating mechanism based on the catalytic converter's activation state. When the catalytic converter is not active, the conversion angle is adjusted to optimize exhaust flow through the catalytic converter, promoting faster activation. This parameter change resolves the contradiction by modifying valve timing to prioritize catalytic converter activation during cold start conditions.

Inventive Principle:

Principle #35Parameter changes

2Power

If the engine is started with a conversion angle not suitable for starting, then the engine output may increase, but HC emissions increase because the catalytic converter cannot effectively clean exhaust gas

Engineering Contradiction:

Improveengine outputVSAvoidHC emissions

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The system changes the conversion angle parameter of the variable valve operating mechanism based on the catalytic converter's activation state. When the catalytic converter is not active, the conversion angle is adjusted to optimize exhaust flow through the catalytic converter, promoting faster activation. This parameter change resolves the contradiction by modifying valve timing to prioritize catalytic converter activation during cold start conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system performs preliminary action by detecting the catalytic converter's activation state before engine start and adjusting the variable valve operating mechanism's conversion angle to an appropriate starting conversion angle in advance. This ensures that when the engine starts, the valve timing is optimized to direct combustion gas through the catalytic converter, enabling it to warm up and activate quickly while still allowing vehicle motion.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9322353B2Engine control apparatus and hybrid vehicle including thereof

Publication Date: 2016.04.26 NISSAN MOTOR CO LTD

AI summary

An engine control apparatus for a hybrid vehicle is provided with a conversion angle detecting device, an angle determining device, an engine load calculating device and an engine control device. The conversion angle detecting device detects a rotational phase of a cam with respect to a crankshaft as a detected conversion angle of a variable valve operating mechanism of an engine. The angle determining device determines if the detected conversion angle is different from a starting conversion angle when the engine is started. The engine load calculating device calculates a requested load to be imposed on the engine based on the detected conversion angle if the detected conversion angle is different from to the starting conversion angle at a time the engine is started. The engine control device controls the engine in accordance with the requested engine load that was calculated.