Vehicle Powertrain Reverse Method via Electric Machine Rotation
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Solution Overview
Problem
Firing a four-stroke internal combustion engine in a reverse direction is typically not suitable for operation without complex valvetrain variability, making it challenging to move a vehicle in reverse effectively.
Innovation Solution
The method involves rotating the IC engine in a first rotational direction via combustion events, commencing shutdown, adjusting intake or exhaust valve timings to decrease rotational resistance, and then rotating the IC engine in a second rotational direction via an electric machine to move the vehicle in reverse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a four-stroke internal combustion engine is fired in a reverse direction to move the vehicle in reverse, then the vehicle can move in reverse direction, but the operation becomes unsuitable without complex valvetrain variability
Solution Approach 1:
Instead of firing the engine in reverse to achieve reverse motion, the patent inverts the approach by using an electric machine to rotate the engine in reverse while keeping the combustion cycle operating in the forward direction. The valve timing is adjusted to accommodate this reversed rotation without requiring complex valvetrain variability, thus achieving reverse vehicle movement through transmission reversal rather than engine firing reversal.
Solution Approach 2:
The patent changes the operational parameters by adjusting the valve timing relative to the combustion cycle when the engine is rotated in reverse by the electric machine. This parameter adjustment allows the engine to be cranked in reverse without requiring complex valvetrain mechanisms, as the valve timing is optimized for the reversed rotation state rather than attempting to fire the engine in reverse.
2Ease of operation
If the IC engine is rotated in reverse direction via combustion events, then reverse movement is achieved, but rotational resistance increases the power requirement
Solution Approach 1:
The patent applies preliminary action by adjusting the valve timing before and during the reverse rotation process. By pre-configuring the valve timing to accommodate reversed rotation, the engine experiences reduced rotational resistance when the electric machine cranks the engine in reverse, thereby lowering the power requirement of the electric machine.
Solution Approach 2:
The patent changes the valve timing parameters specifically for reverse rotation operation. By optimizing the valve opening and closing timings relative to the combustion cycle during reversed engine rotation, the rotational resistance is minimized, reducing the energy required by the electric machine to achieve reverse movement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for efficient reverse movement of a vehicle without the need for complex valvetrain variability, reducing the power requirement of the electric machine and simplifying the powertrain configuration.
Implementation Method 1
rotating the IC engine in a second rotational direction via an electric machine
Implementation Method 2
decompressing the IC engine such that the combustion chamber is continuously vented throughout a duration of each upward stroke of the piston within the engine cylinder
Implementation Method 3
adjusting at least one of an intake valve timing from the first intake valve timing to a second intake valve timing relative to a firing engine combustion cycle in order to decrease a rotational resistance of the IC engine
Data Source
AI summary
A method for moving a vehicle in a reverse direction is provided. The method includes: providing an internal combustion engine, a transmission, and an electric machine; adjusting a valve timing of either an intake valve or an exhaust valve during a non-firing mode of the internal combustion engine to reduce a rotational resistance; and, rotating the internal combustion in a backwards or reverse direction so that the vehicle moves in a reverse direction.