ALFA ROMEO GIULIA AND CONTINENTAL: THE PARTNERSHIP
Brakes
Already famous, the new sedan combines style and comfort with a dynamic and reliable road behavior. Part of this captivating feeling stems from an innovative Continental braking system, which we will closely examine in the following article
Nicodemo Angì
The new D-segment Alfa sedan has a respectable and sophisticated technical outfit which stems from the fact that the car was designed starting from a blank sheet, or almost. The technical features borrowed from the Group's other brands are prestigious indeed, such as the Quadrifoglio V6 engine created through a collaboration with Ferrari and the front end which greatly resembles that of a Maserati. Not to mention the carbon fiber transmission shaft and, in fact, the integrated MK C1 braking system by Continental. The German group, as we well know, has recently started to add to its traditional activity as a tire manufacturer, a well-diversified portfolio of sophisticated components, such as advanced driver assistance systems (ADAS) and sophisticated braking systems.
Simulating the system
The MK C1 appears truly innovative and was designed to perfectly equip hybrid traction systems fulfilling the requirements for a regenerative braking system without any additional measures, likely to become more and more necessary to meet the already stringent – but more so in the future - emissions regulations.
This integrated component allows in fact to implement, with relative ease, a drive-by-wire braking system where the pedal is decoupled from the hydraulic circuit, which allows other interesting advantages, such as actuation speed and pedal feeling adjustable via software.
The MK C1 braking system from Continental combines the brake actuation, booster, and control systems into a single braking unit; connections are therefore limited to the vehicle's wiring system, its data network and the pipes that carry the brake fluid to the brake calipers.
Gone, as already anticipated, the vacuum brake booster and its vacuum pump, replaced by an electric pump driven by a brushless DC motor (BLDC). The traditional tandem pump connected to the pedal is still present but, under normal conditions, will intervene only to transfer to the pedal - and therefore to the driver - the load simulator which reproduces the sensations of a more traditional system. The movement of the piston is read by sensors, and the signals are used to drive the working cylinder, operated by the above mentioned brushless DC motor. The conversion of the motor’s rotation into the linear movement of the piston takes place via a ball-and-screw system, a screw-nut screw system perfected by placing steel balls between the two threads: the rolling friction thus obtained guarantees a smooth and fluid movement with reduced resistance.
Failure free
The load on the nut comes from a single direction - from the piston side of the working pump - making it possible to calculate with great precision the relative piston position.
This ball-and-screw actuator is designed to be maintenance-free, but in case of failure (however unlikely) braking is guaranteed by the pump connected to the pedal and the same would happen even in the event of a complete power supply failure. The size of the pump connected to the tandem brake pedal ensures in any event the minimum braking efficiency prescribed by law (6.43 m/s2 with a pedal pressure of 500 N) even if the vehicle should weigh 2 tons or more.
Furthermore, the absence of the bulky shell of a conventional brake booster makes it possible to gain a further 10 cm in the front end of the vehicle, which can be used to increase the depth of the crumple zone in front of the occupant compartment. The system’s compatibility with ABS and ESC systems, which have a flow and return valve for each wheel, is guaranteed and, as far as the MK C1 is concerned, the valve system has been perfected further, just as its sensors.
Tailor-made braking
Decoupling the pressure on the pedal from the wheels has several advantages, such as no reaction to the pedal when the ABS or ESC systems are activated, or the type of braking intervention set by software and therefore easily adaptable to different brands and models. The sensors can even perceive the load the driver puts on the pedal: if it corresponds to a slight braking, which statistically represents about 80% of all braking, the modulation of the force occurs through the pedal stroke. If the driver, on the other hand, suddenly needs much more braking power, direct pressure on the pedal will provide what is needed.
Additionally, this system is ideal also on hybrid vehicles (so probably we will soon see a hybrid versions of the Giulia and the SUV Stelvio), where braking energy recovery is possible only at a certain speed range. The MK C1 system can effectively manage this function, producing the desired deceleration even when the energy recovery system "hands over" things to the more traditional brakes. The system efficiently works on principles of power on demand and, even if the maximum absorption is almost 100 A, it is only for short moments and then falls; if the system is not activated at all, then it will all be reduced to a slight consumption of the electronic part.
The system has shown remarkable readiness, which is essential if the automatic emergency braking system is to function properly and avoid possible collisions and pedestrians suddenly appearing in front of the car. Tests performed at a speed of 66 km / h saw a car equipped with the MK C1 stop after 18 meters while a more "traditional" car stopped after 23 meters and after 18 meters was still moving at 36 km/h.
“Future and complication proof”
This system so compact and efficient has proved so interesting that we wanted to learn more; therefore, taking advantage of Continental’s efficient press office, we forwarded a few questions to the specialists who deal with it.
Asked if the MK C1 was compatible without further modification with existing driver assistance systems (Adaptive Cruise Control, Emergency Brake and the like) we were given an affirmative answer. Not only no modifications are required, but the dynamic pressure is 3 times higher compared to current ESC systems; meaning that the system is also ready for autonomous driving!
Power absorption is not a problem too, since other onboard systems absorb more than the peak 80 amps of this system; Alfa Romeo came up with an electrical system that easily meets the needs with minimal voltage fluctuation.
The last question revolved around the necessary data for the system to function: are changes to bus on-board systems (CAN, Flexray and the like) required to manage the MK C1? The answer was that the system works with commonly available data on both cars and busses and not only; the system is in fact simplified, since the vacuum pump, the switch on the brake pedal and the various piping and assorted ESC support systems have been eliminated.
ALFA ROMEO GIULIA AND CONTINENTAL: THE PARTNERSHIP
Brakes
Already famous, the new sedan combines style and comfort with a dynamic and reliable road behavior. Part of this captivating feeling stems from an innovative Continental braking system, which we will closely examine in the following article
Nicodemo Angì
The new D-segment Alfa sedan has a respectable and sophisticated technical outfit which stems from the fact that the car was designed starting from a blank sheet, or almost. The technical features borrowed from the Group's other brands are prestigious indeed, such as the Quadrifoglio V6 engine created through a collaboration with Ferrari and the front end which greatly resembles that of a Maserati. Not to mention the carbon fiber transmission shaft and, in fact, the integrated MK C1 braking system by Continental. The German group, as we well know, has recently started to add to its traditional activity as a tire manufacturer, a well-diversified portfolio of sophisticated components, such as advanced driver assistance systems (ADAS) and sophisticated braking systems.
Simulating the system
The MK C1 appears truly innovative and was designed to perfectly equip hybrid traction systems fulfilling the requirements for a regenerative braking system without any additional measures, likely to become more and more necessary to meet the already stringent – but more so in the future - emissions regulations.
This integrated component allows in fact to implement, with relative ease, a drive-by-wire braking system where the pedal is decoupled from the hydraulic circuit, which allows other interesting advantages, such as actuation speed and pedal feeling adjustable via software.
The MK C1 braking system from Continental combines the brake actuation, booster, and control systems into a single braking unit; connections are therefore limited to the vehicle's wiring system, its data network and the pipes that carry the brake fluid to the brake calipers.
Gone, as already anticipated, the vacuum brake booster and its vacuum pump, replaced by an electric pump driven by a brushless DC motor (BLDC). The traditional tandem pump connected to the pedal is still present but, under normal conditions, will intervene only to transfer to the pedal - and therefore to the driver - the load simulator which reproduces the sensations of a more traditional system. The movement of the piston is read by sensors, and the signals are used to drive the working cylinder, operated by the above mentioned brushless DC motor. The conversion of the motor’s rotation into the linear movement of the piston takes place via a ball-and-screw system, a screw-nut screw system perfected by placing steel balls between the two threads: the rolling friction thus obtained guarantees a smooth and fluid movement with reduced resistance.
Failure free
The load on the nut comes from a single direction - from the piston side of the working pump - making it possible to calculate with great precision the relative piston position.
This ball-and-screw actuator is designed to be maintenance-free, but in case of failure (however unlikely) braking is guaranteed by the pump connected to the pedal and the same would happen even in the event of a complete power supply failure. The size of the pump connected to the tandem brake pedal ensures in any event the minimum braking efficiency prescribed by law (6.43 m/s2 with a pedal pressure of 500 N) even if the vehicle should weigh 2 tons or more.
Furthermore, the absence of the bulky shell of a conventional brake booster makes it possible to gain a further 10 cm in the front end of the vehicle, which can be used to increase the depth of the crumple zone in front of the occupant compartment. The system’s compatibility with ABS and ESC systems, which have a flow and return valve for each wheel, is guaranteed and, as far as the MK C1 is concerned, the valve system has been perfected further, just as its sensors.
Tailor-made braking
Decoupling the pressure on the pedal from the wheels has several advantages, such as no reaction to the pedal when the ABS or ESC systems are activated, or the type of braking intervention set by software and therefore easily adaptable to different brands and models. The sensors can even perceive the load the driver puts on the pedal: if it corresponds to a slight braking, which statistically represents about 80% of all braking, the modulation of the force occurs through the pedal stroke. If the driver, on the other hand, suddenly needs much more braking power, direct pressure on the pedal will provide what is needed.
Additionally, this system is ideal also on hybrid vehicles (so probably we will soon see a hybrid versions of the Giulia and the SUV Stelvio), where braking energy recovery is possible only at a certain speed range. The MK C1 system can effectively manage this function, producing the desired deceleration even when the energy recovery system "hands over" things to the more traditional brakes. The system efficiently works on principles of power on demand and, even if the maximum absorption is almost 100 A, it is only for short moments and then falls; if the system is not activated at all, then it will all be reduced to a slight consumption of the electronic part.
The system has shown remarkable readiness, which is essential if the automatic emergency braking system is to function properly and avoid possible collisions and pedestrians suddenly appearing in front of the car. Tests performed at a speed of 66 km / h saw a car equipped with the MK C1 stop after 18 meters while a more "traditional" car stopped after 23 meters and after 18 meters was still moving at 36 km/h.
“Future and complication proof”
This system so compact and efficient has proved so interesting that we wanted to learn more; therefore, taking advantage of Continental’s efficient press office, we forwarded a few questions to the specialists who deal with it.
Asked if the MK C1 was compatible without further modification with existing driver assistance systems (Adaptive Cruise Control, Emergency Brake and the like) we were given an affirmative answer. Not only no modifications are required, but the dynamic pressure is 3 times higher compared to current ESC systems; meaning that the system is also ready for autonomous driving!
Power absorption is not a problem too, since other onboard systems absorb more than the peak 80 amps of this system; Alfa Romeo came up with an electrical system that easily meets the needs with minimal voltage fluctuation.
The last question revolved around the necessary data for the system to function: are changes to bus on-board systems (CAN, Flexray and the like) required to manage the MK C1? The answer was that the system works with commonly available data on both cars and busses and not only; the system is in fact simplified, since the vacuum pump, the switch on the brake pedal and the various piping and assorted ESC support systems have been eliminated.