Hybrid Vehicle Simulated Shifting via Engine Speed Control
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Solution Overview
Problem
Hybrid vehicles lack the engine sound cues associated with downshifting, which can lead to a less engaging driving experience for drivers accustomed to conventional step transmissions, as the engine speed in ECVTs is not directly linked to vehicle acceleration or speed.
Innovation Solution
A hybrid vehicle system that simulates downshifting by increasing engine speed without changing the applied torque to the wheels when a requested deceleration torque exceeds that of a lower simulated gear, using a processor, sensor, and memory to manage target engine speeds and torque for each simulated gear, and includes a paddle shifter for manual shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an ECVT is used to control engine speed independently of vehicle speed, then fuel economy is improved and smooth acceleration is achieved, but the driver loses audible engine sound cues and the sporty feel associated with downshifting
Solution Approach 1:
The system creates a virtual copy of the downshifting experience by generating simulated engine sounds and visual displays that mimic conventional transmission behavior. The audio output device plays recorded engine sounds at different pitches to simulate gear changes, while the display device shows simulated tachometer readings, allowing drivers to experience the sporty feel of downshifting without actual gear changes occurring in the ECVT system.
Solution Approach 2:
The system introduces intermediary devices (audio output device and display device) that mediate between the ECVT's continuous transmission ratio control and the driver's expectations for discrete gear shift cues. These intermediaries translate the continuous engine speed control into discrete-sounding events that provide audible and visual feedback similar to conventional transmissions.
2Productivity
If sequential gear logic with automatic upshifting is implemented, then fuel efficiency is maintained, but automatic downshifting capability is lost and engine sounds during braking are eliminated
Solution Approach 1:
The system dynamically adjusts the simulated gear state based on real-time driving conditions, particularly during braking events. When deceleration is detected, the system transitions the simulated gear state to lower gears and plays corresponding engine sounds, creating a dynamic response that adapts to driver behavior while maintaining the underlying ECVT's fuel-efficient operation.
Solution Approach 2:
The system changes audio parameters (pitch, volume) and display parameters (simulated RPM values) based on the simulated gear state and detected driving conditions. During braking, the system modifies these parameters to simulate lower gear engagement, providing versatile driving experience enhancement without altering the physical transmission parameters.
3Stability of the object's composition
If the engine speed is modulated with motor-generator output for smooth acceleration, then acceleration smoothness is improved, but the engine flares and noise cues associated with gear shifts are eliminated
Solution Approach 1:
The system employs periodic engine sound playback that corresponds to simulated gear shift events. During braking, the system triggers periodic audio outputs that mimic the characteristic engine flares of downshifting, creating rhythmic sound patterns that provide periodic feedback cues to the driver while the actual acceleration remains smooth and continuous.
Data Source
AI summary
A system for simulated shifting for a hybrid vehicle, the system includes a plurality of wheels, an engine, a sensor, a transmission, a memory for storing target engine speeds and deceleration torques for a plurality of simulated gears, and a processor. The engine provides a torque to the plurality of wheels. The sensor detects a requested deceleration torque. The transmission simulates a current simulated gear by delivering an applied torque, which corresponds to the requested deceleration torque, to the plurality of wheels and an engine speed corresponding to the simulated gear. The processor simulates a downshift by increasing an engine speed of the engine without changing the applied torque to the plurality of wheels when the requested deceleration torque exceeds a deceleration torque of a lower simulated gear.