Company News

Analysis of BorgWarner Variable Cam Phase Technology

2019-09-20

Intermediate position lock diagram
Since the initial phase of the conventional variable valve phase system is one end of the angular range of the phaser, the engine low temperature starting performance and calibration strategy are limited by the angle of adjustment designed when designing the variable timing system. For example, in the Atkinson cycle and the Miller cycle engine, the hysteresis angle of the intake phaser needs to be further increased during the intake reverse flow. If the lock is still at the end face, the system cannot balance the hot start and the cold. The valve overlap angle that is activated.
BorgWarner‘s intermediate position locking technology‘s initial position is set in an intermediate position, which allows for greater adjustment angles and better airflow control, resulting in improved fuel economy and efficiency. Under virtually any possible engine operating conditions, a patented hydraulic circuit automatically moves the system to an intermediate position for a reliable reset process. The advantages of intermediate position locking technology are summarized as follows:
- Intermediate lock for engine Atkinson cycle and Miller cycle, and can be locked in any position required by the customer
- The phaser can actively return to the locked position when the engine is not normally shut down
- Small or no changes to the engine cylinder head and cylinder block
Electronic phaser
 
Electronic phaser size
OPA, TA, and CTA are all hydraulic phasers. On top of this, BorgWarner has electronic phaser technology for high-end models, which is costly but more outstanding. According to BorgWarner engineers, the modular design allows the phaser to be executed at a larger angle than the hydraulic phaser. The electronic phaser performs at a speed that is unaffected by oil pressure and improves the response of the engine at low engine speeds. Second, it uses the same phaser on different engine platforms, is universal, has a larger range of adjustment angles, and allows the application of new engine calibration strategies.
The electronic phaser is driven by a chain. The outer wheel has a planetary gear mechanism. The center is a sun gear mechanism connected to the motor. The middle planet carrier is connected to the camshaft. The chain and the sun wheel are input in two directions, and the planet carrier is output all the way. The sun gear has two outer ring gears. The planetary gears produce a speed difference when meshing with the outer ring gear to achieve phase adjustment. If the sun gear accelerates, the phase lags. If the sun gear rotates, the phase advances.
 
Electronic phaser structure diagram
The following picture shows the performance comparison between BorgWarner electronic phaser and competing products on the Mazda SkyActive engine. BorgWarner‘s product (red) phase execution speed is significantly higher than competing products (blue), only under high speed conditions (about 5800) -6000 rpm), the running speed in the lag direction will be slightly slower than competing products.
 
Performance comparison between BorgWarner electronic phaser and competing products on Mazda SkyActive engine
Engineers pointed out that the efficiency of the phaser planetary gear mechanism has been further improved, and the products will be better than the red line in the figure. It is expected that in the next two years, Chinese car companies will conduct preliminary development and exploration of this technology.
AirFinityVVA variable valve drive technology
 
AirFinity technology eliminates the intake camshaft of the engine
“As future energy regulations become more stringent, perhaps this technology will become a trend after 5-6 years,” engineers predict. AirFinityVVA represents the state of the art in advanced variable valve actuation technology. It is known to utilize the valve control and manufacturing technology of the BorgWarner Morse system, using a bolt-on modular assembly that eliminates the need for an intake camshaft and provides a fully variable valve lift curve to support multiple control strategies. Suitable for all piston engines. In addition, it is not just a product, but a series. The later generations of research and development will focus on a more flexible continuous variable valve lift design, which will make the engine completely free of intake and exhaust camshafts. Therefore, AirFINITY can achieve the most compact direct injection engine layout.