Vehicle Powertrain Control for Atkinson-to-Otto Torque Response
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Solution Overview
Problem
Existing vehicle control systems that operate internal combustion engines in the Atkinson cycle experience delays in reducing engine torque and vehicle acceleration when the accelerator pedal operation amount decreases, due to air being pushed back into the intake passage, leading to delayed deceleration of vehicle acceleration.
Innovation Solution
A vehicle controller that adjusts the gear ratio of the transmission and intake valve timing to reduce the delay in engine torque decrease by executing first and second gear ratio adjustment processes and corresponding intake VVT adjustments, allowing the engine to operate in the Otto cycle when the accelerator pedal operation amount decreases, thereby reducing air pushed back into the intake passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the intake valve timing is retarded to operate the engine in the Atkinson cycle, then fuel consumption is reduced, but the response delay of vehicle acceleration to accelerator pedal operation increases
Solution Approach 1:
The patent applies dynamics by making the intake valve timing adjustable rather than fixed. The variable valve actuation device allows the intake valve timing to be dynamically changed between retarded timing (Atkinson cycle for fuel efficiency) and advanced timing (faster response). This enables the system to adapt the valve timing based on driving conditions, resolving the contradiction between fuel consumption and acceleration response.
Solution Approach 2:
The patent changes the parameter of intake valve timing from a fixed retarded state to a variable state. By adjusting the intake valve timing parameter forward when rapid acceleration is needed, the system reduces the amount of air pushed back to the intake passage, thereby reducing engine torque delay and improving vehicle acceleration response while maintaining the ability to operate in Atkinson cycle for fuel efficiency.
2Speed
If the gear ratio of the transmission is adjusted to improve acceleration response, then vehicle acceleration response improves, but engine operating conditions may become suboptimal
Solution Approach 1:
The patent merges the control of transmission gear ratio adjustment with intake valve timing adjustment. Instead of relying solely on transmission gear ratio changes to improve acceleration response, the system combines this with variable intake valve timing control. This coordinated approach allows the engine to maintain more optimal operating conditions while still achieving improved acceleration response, as the valve timing can be optimized for the specific gear ratio and engine load conditions.
Data Source
AI summary
The vehicle controller controls a vehicle. The vehicle includes a transmission and an internal combustion engine that has a variable valve actuation device. The vehicle controller includes an execution device. The execution device executes first and second gear ratio adjustment processes and first and second intake VVT adjustment processes. The first intake VVT adjustment process includes adjusting the intake valve timing such that the internal combustion engine is operated in an Atkinson cycle. The second intake VVT adjustment process includes setting the intake valve timing such that the closing timing of the intake valve is more advanced than in a case in which the first intake VVT adjustment process is executed.