Hybrid Vehicle Engine Speed-Torque Control for Quiet Knock-Limited Charging

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Solution Overview

Problem

In hybrid vehicles, reducing engine rotation speed to minimize noise while preventing knocking, which occurs due to high engine torque and long flame propagation times at low speeds, is a challenge.

Innovation Solution

A hybrid vehicle control device that calculates a knock index value based on engine rotational speed and torque, and adjusts the target engine rotation speed and torque to be lower and higher, respectively, as the knock index value decreases, within a range that prevents knocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If engine rotation speed is reduced to minimize noise, then engine noise is reduced, but knocking is likely to occur due to high engine torque and long flame propagation time

Engineering Contradiction:

Improveengine noiseVSAvoidknocking

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The control device continuously monitors the actual knock level during engine operation and dynamically adjusts ignition timing based on feedback signals. When knocking is detected, the ignition timing is retarded; when no knocking occurs, timing is advanced or maintained, creating a closed-loop control system that optimizes combustion while preventing excessive knock

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes ignition timing parameters dynamically based on operating conditions. By adjusting ignition timing as a controllable parameter, the system can accommodate lower engine speeds and higher torques while maintaining acceptable knock levels, thus enabling noise reduction without sacrificing reliability

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If engine rotation speed is reduced to enhance quietness, then quietness is improved, but power generation output may be insufficient

Engineering Contradiction:

Improveengine noiseVSAvoidpower generation output

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The system adjusts ignition timing parameters to optimize the balance between noise reduction and power generation. By carefully controlling ignition timing, the system maintains adequate combustion efficiency and power output even at reduced engine speeds, while still achieving noise reduction goals

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12233846B2Hybrid vehicle control device

Publication Date: 2025.02.25 ASTEMO LTD

AI summary

Provided is a hybrid vehicle control device excellent in quietness while suppressing knocking within an allowable limit. The hybrid vehicle control device of an aspect of the invention is a hybrid vehicle control device that controls a hybrid vehicle including a motor that drives wheels, a generator that supplies electric power to the motor, and an engine configured by an internal combustion engine that drives the generator, and includes a control unit that calculates a knock index value indicating a knock degree of the engine at an engine operating point represented by a relationship between an engine rotational speed and an engine torque, and controls the engine rotational speed and the engine torque based on the knock index value. As the knock index value decreases, the control unit sets the target engine rotation speed to be lower and the target engine torque to be higher in the target power generation amount.