Hybrid Electric Vehicle Rev-Matching Control

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Solution Overview

Problem

Conventional hybrid electric vehicles (HEVs) lack the desired driving experience in sport mode due to engine response not matching that of conventional manual or automatic transmissions, particularly in terms of rev-matching during downshifting, which results in a lack of increased sound and response.

Innovation Solution

The implementation of an electronic control unit that simulates gear shifts by adjusting the rotational speed of the internal combustion engine and motor generator, allowing for targeted engine speed increases based on gear ratios, accelerator pedal actuation, and vehicle speed, thereby mimicking the rev-matching experience of manual transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional automatic transmissions or CVTs are used in HEVs, then ease of operation is improved, but the driving experience and engine response during downshifting deteriorate

Engineering Contradiction:

Improveease of operationVSAvoiddriving experience

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system copies the rev-matching behavior of manual transmissions by using the motor generator to artificially increase engine speed during downshifts, replicating the auditory and responsive characteristics of manual gear changes without requiring a manual transmission mechanism

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The system changes the engine speed parameter dynamically during downshifts by controlling the motor generator to augment engine rotational speed, creating the desired rev-matching effect that enhances driving experience while maintaining automatic transmission operation

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If engine speed is increased during downshifts to simulate rev-matching, then driving experience is improved, but energy consumption increases

Engineering Contradiction:

Improvedriving experienceVSAvoidenergy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The motor generator serves multiple functions: it acts as a motor to augment engine speed during downshifts for rev-matching, and as part of the hybrid powertrain for propulsion and energy recovery, maximizing the utility of this component while managing energy consumption

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically adjusts engine speed augmentation based on driving conditions, downshift timing, and energy availability, applying rev-matching only when beneficial for driving experience rather than continuously, thereby optimizing energy consumption

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11565581B2Sequential simulated gear ratio calculation and rev-matching in a hybrid electric vehicle

Publication Date: 2023.01.31 TOYOTA JIDOSHA KK

AI summary

Systems and methods are provided for simulating rev-matching in hybrid electric vehicles (HEVs). In particular, increased engine response is provided while downshifting during acceleration. The transmission of an HEV may include an electronic control unit that controls the speed of the engine to simulate gears, and increases the speed of the engine responsive to a driver using the gear selector to shift from one of the simulated gears to a lower one of the simulated gears, thereby providing the desired rev-matching experience. The increased engine response can be reflected in a target engine speed that is calculated based on specific gear ratios associated with each of the simulated gears.