Engine Torque Control via Variable Valve Timing and Duration
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Solution Overview
Problem
Existing engine control methods face a time delay in responding to sudden changes in demanded torque due to the operation of throttle valves and turbochargers, making it impossible to quickly adjust engine torque according to driver input.
Innovation Solution
An engine control apparatus and method utilizing a variable valve timing device and a variable valve duration device to adjust intake valve timings and durations, allowing for quick responses to changes in demanded torque by controlling air flow rates within the cylinder, specifically by fixing intake valve opening timing and adjusting closing timing through these devices in conjunction with throttle valve and supercharger control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If throttle valve or turbocharger is operated to adjust torque, then torque control is achieved, but time delay of about 2 seconds occurs
Solution Approach 1:
The variable valve timing device and variable valve duration device are activated in advance during the transition section before the throttle valve or supercharger can respond. By pre-adjusting the intake valve timing and duration, the system prepares the cylinder air charge in advance, eliminating the 2-second delay when torque adjustment is eventually needed.
Solution Approach 2:
The patent introduces variable valve timing and variable valve duration devices as intermediary mechanisms between the driver's torque demand and the final torque output. These devices mediate the torque adjustment process by controlling intake valve timing and duration, providing a faster response path that bypasses the slow thermal and mechanical response of throttle valves and turbochargers.
2Speed
If variable valve timing device and variable valve duration device are used to adjust intake valve timings, then response speed to torque change is improved, but device complexity increases
Solution Approach 1:
The variable valve timing device and variable valve duration device perform multiple functions: they control intake valve timing, adjust intake valve duration, manage cylinder air charge, and enable fast torque response. By making these valve control devices multi-functional, the patent achieves fast response speed without adding separate dedicated systems for each function, thereby limiting the increase in overall device complexity.
3Productivity
If controller adjusts amount of air inside cylinder by fixing IVO timing and adjusting IVC timing, then torque adjustment speed is improved, but control complexity increases
Solution Approach 1:
The controller changes the timing parameters of the intake valve, specifically fixing the intake valve opening (IVO) timing and adjusting the intake valve closing (IVC) timing. By varying these temporal parameters through the variable valve timing device, the system achieves fast torque adjustment without complex mechanical reconfigurations, as parameter changes can be implemented through electronic control of existing actuation mechanisms.
Data Source
AI summary
An apparatus for controlling an engine includes: an engine with a cylinder; a throttle valve to adjust a flow rate of intake air supplied to the cylinder; a supercharger to supply supercharged air to the cylinder; an intake valve to supply intake air by selectively opening and closing the cylinder; a variable valve timing device to adjust opening and closing timings of the intake valve; a variable valve duration device to adjust an opening duration of the intake valve; and a controller to adjust the amount of air inside of the cylinder by fixing an intake valve opening (IVO) timing and adjusting an intake valve closing (IVC) timing through the variable valve timing device and the variable valve duration device from a time at which a demanded torque is input to a time at which the demanded torque is followed by the throttle valve or the supercharger.