Which cruise control system is the best?

With the development of technology, vehicle assisted driving systems are becoming more and more diversified, cruise control, ACC adaptive cruise control and predictable cruise control have different experiences, which can get more truckers' favor?

First, let's talk about cruise control (CCS). Its principle is very simple. The cruise control component installed on the vehicle reads the pulse signal sent by the vehicle speed sensor. It then compares this signal with the speed set by the cruise control system. Subsequently, the cruise control component issues instructions to adjust the throttle opening through mechanical structures, ensuring that the vehicle maintains the set speed for long-distance travel. To simplify, cruise control sets a target speed for the vehicle, and the vehicle will continuously operate within this speed range.

This also means that once the cruise control function is activated, drivers won't need to step on the accelerator pedal, as the vehicle will maintain a constant speed forward. When obstacles appear ahead, drivers only need to turn the steering wheel or press the brake. However, it's important to note that for most trucks, the logic of using cruise control involves reactivating and adjusting the preset speed value after pressing the brake, before reactivating cruise control again.

So, in the actual usage process, this function simply eliminates the need to step on the accelerator pedal, while steering and braking still require manual control. Additionally, since cruise control operates based on speed commands as the highest directive, once activated, if drivers need to accelerate or encounter uneven road surfaces, cruise control will only adjust the throttle opening according to the set speed. If the uphill angle is steep, cruise control will disregard fuel economy concerns and aggressively downshift to increase engine speed, ensuring the vehicle maintains the set speed.

In short, many experienced drivers adjust gears based on their experience when facing steep slopes to balance fuel efficiency and speed, making it easier for the vehicle to handle. Cruise control, on the other hand, lacks this "wisdom" and simply presses the accelerator without making adjustments in other aspects.

Most drivers tend to use cruise control mainly on flat, straight, and less congested roads. They typically intervene manually when encountering heavy traffic or sharp turns. Moreover, when facing high-altitude terrains or steep slopes, nearly 98% of drivers intervene manually. This indicates that although cruise control alleviates the need to control the throttle and slightly reduces fatigue during long-distance drives, it is evidently not intelligent enough.

This is why, despite many trucks being equipped with cruise control, its actual usage rate is not very high. Additionally, since most trucks are designed with manual transmissions, cruise control is only effective when the vehicle is already within the speed preset range and experiencing minimal fluctuations. If you manually shift gears, it will disrupt cruise control's control.

As a result, building upon cruise control, Adaptive Cruise Control (ACC) has been introduced, featuring a rare application of millimeter-wave radar technology in vehicles. This technology, combined with the familiar Forward Collision Warning System (FCWS), aims to equip vehicles with collision prevention and automatic braking capabilities.

Its principle involves the emission of millimeter-wave electromagnetic waves by a millimeter-wave radar. These waves are projected onto obstacles ahead, and the real-time distance to the obstacle is determined by analyzing the time difference between the emitted waves and the reflected waves. Additionally, the relative velocity between the two vehicles is determined using frequency shift techniques applied to the reflected waves. Why use millimeter waves? Because millimeter waves can penetrate fog, smoke, dust, and other obstructions, offering all-weather and all-day characteristics. Additionally, the long-range radar commonly used in radar systems operates at around 77GHz and can typically anticipate obstacles at distances ranging from 100 to 300 meters ahead.

With this technology, coupled with additional automatic braking functionality and complemented by the control features of cruise control, intelligent acceleration and deceleration of vehicles can be achieved. For instance, after activating Adaptive Cruise Control (ACC) and setting the desired target speed, the vehicle can accelerate based on the set speed. When the millimeter-wave radar detects obstacles ahead, it automatically controls the vehicle to decelerate and maintains a cruising speed relative to the vehicle ahead.

In other words, the Adaptive Cruise Control (ACC) function can assist drivers in controlling the vehicle's throttle and brakes on normal roads. It can also alert drivers to brake when obstacles are detected ahead, or autonomously initiate braking. Moreover, advanced ACC systems can automatically adjust the following distance by setting a value relative to the distance to the preceding vehicle. If both your vehicle and the vehicle ahead depart simultaneously, cruising at 80 km/h on the same route, theoretically, you only need to steer the wheel properly to arrive at the destination together with them.

Therefore, we can consider Adaptive Cruise Control (ACC) as an advanced version of cruise control. During long-distance drives, throttle and brake control can be almost entirely delegated to ACC, leaving us with the task of simply steering the wheel steadily. However, it's important to note that ACC is currently only available on trucks equipped with automatic transmissions. Manual transmission trucks lack the necessary hardware, such as the Transmission Control Unit (TCU), for advanced computations, making it difficult to implement this feature.

However, while Adaptive Cruise Control (ACC) can significantly reduce driver fatigue, it still cannot achieve precise control over engine throttle opening or fuel injection quantity. Therefore, when facing long uphill stretches or continuous undulating road sections, its performance is similar to traditional cruise control in that it cannot take into account the vehicle's fuel economy.

Due to the fact that in actual driving, drivers not only have demands for comfort but also highly value the vehicle's fuel consumption performance, predictive cruise control functions have emerged. This is also an exclusive feature in the commercial vehicle industry. Taking Mercedes-Benz's PPC (Predictive Powertrain Control) proactive predictive assistance driving as an example, its basic principle involves anticipating the road conditions ahead in advance and adjusting the vehicle's powertrain parameters in real-time to achieve optimal power output and driving strategy.

The PPC predictive driving function utilizes GPS satellite positioning systems to monitor the road segment ahead for a distance of 1-1.5 kilometers. This system can accurately calculate key information such as the elevation, slope, curves, and other parameters of the road segment ahead, creating a comprehensive 3D map. 

Then, this information is organized and transmitted through the vehicle's ECU to areas such as the engine and transmission, where adjustments are made to their parameters. For example, if there's a continuous uphill slope about 500 meters ahead, the vehicle will preemptively adjust its power output based on the information provided, enhancing the vehicle's average speed and reaching an optimal speed performance before ascending. This allows for achieving the best shifting time during continuous uphill sections, ultimately saving fuel consumption during climbs.

Additionally, during downhill sections, the system can accurately locate the vehicle's position using the provided information. This enables the vehicle to utilize coasting mode in combination with the hydraulic retarder and engine braking for extended downhill operation. According to estimates from Mercedes-Benz, when using PPC predictive cruise control throughout the journey, fuel consumption can be reduced by up to around 5% compared to standard fuel consumption rates, significantly improving fuel efficiency.

Many drivers used to believe that achieving both effortless driving and fuel efficiency was impossible. In other words, they thought that you needed to be extremely focused on driving to achieve optimal fuel economy. However, with the introduction of predictive cruise control, an increasing number of commercial vehicle manufacturers are now investing in the field of intelligent driver assistance. As a result, driving trucks will no longer be a tiring and mentally exhausting task. Moreover, it will provide better safety and efficiency guarantees.