In the article "Depth: Summary of the Technical Status of the Great Wall Gun Off-road Pickup Truck Length 15000km", the technical status of the appearance, interior, power, transmission and suspension of the Great Wall Gun Off-road Pickup Truck with passability as the goal is emphatically introduced.
In this review, we will focus on the shift control strategy in automatic and manual modes of the expressway with the total mileage of the Great Wall gun off-road pickup truck exceeding10.5 million kilometers, and the ancient Tang-Fan road (Xining to Yushu) with an altitude of over 4,500 meters, as well as the reliability of the 2.0T engine in low temperature environment.
1, pavement? 8AT shift strategy:
From Xining to Tangfan Ancient Road (G063 1 National Road), via maduo county and Yushu to Leiuqi to National Road 3 17, then to Naqu, and finally to Lhasa. The elevation of this road gradually climbed from 2000 meters to 3000 meters, 4000 meters or even 5200 meters. The passing roads have also changed from dry roads and snowy roads to muddy and slippery gravel roads. Great Wall Gun's off-road pickup truck tests not only the torque distribution response speed of TOD multi-disc clutch four-wheel drive system before and after different road conditions, but also the power output performance of 2.0T engine at high altitude and 8AT shift control strategy.
On the paved road at an altitude of 2,000m, the semi-independent structure of front double A-type swing arm suspension and rear "5-link"+integral bridge provides sufficient support and good comfort for the Great Wall gun off-road pickup truck with passenger capacity and luggage capacity exceeding 2.4 tons. The cross-country version of the Great Wall Gun is mainly set on the passability of complex road conditions, and the suspension adjustment is obviously "hard", which obviously inhibits the "nodding" phenomenon during emergency braking.
At an altitude of 2200m, choose the normal driving mode, control the vehicle speed at 10 1km/h, and keep the 2.0T engine speed at 1700rpm. At this time, the instantaneous fuel consumption is 6.8L/ 100km. The Great Wall gun off-road pickup truck has set six preset driving modes for this 8AT, such as sports, environmental protection, ordinary, sand and song.
Among them, SPORT\ECO\NORMAL mode is mainly used for pavement with good adhesion; The sand/snow mode is mainly used for complex road conditions with different adhesion.
In the normal mode, the shift control system habitually and quickly rises to the top gear, 8th gear. In the process of slow acceleration, the system will increase the engine speed according to the stroke and speed of deeply stepping on the accelerator pedal in exchange for better acceleration. In the process of rapid acceleration, the accelerator pedal is depressed quickly and deeply, and the system gives priority to downshifting while increasing the engine speed to obtain better acceleration. In the actual test process, there will often be a continuous downshift of 2 or even 3 gears, and the engine speed will enter 5000 rpm, so as to safely and quickly complete the action of overtaking the preceding vehicle.
When driving in normal mode, control the shift paddle on the left side of the multi-function steering wheel (downshift on the left side and upshift on the right side) to enter the manual shift mode, and at the same time, forcibly downshift (touch 1 gear once, and continuous downshift can be completed by continuous touch). With the accelerator pedal deeply depressed, the vehicle runs at a constant speed, and it changes from manual shift mode to normal mode.
The engine speed is 5000 rpm, and the altitude of the third gear in manual shift mode climbs to 3660 meters, and the normal mode is still selected (the on-board driving computer shows that it is in the uphill state). The 2.0T engine has abundant power output, which can cope with the torque required for long-distance acceleration even if the power decays at high altitude.
The speed of off-road pickup truck of Great Wall Gun is kept at 100km/h, and the default normal mode is changed to sports mode. The system automatically reduces the engine speed by two gears (8 -6), from 65,438+700 rpm to 200 rpm, achieving better power performance.
Driving on the paved road at an altitude of 4 100 meters, choose the sports mode. The engine speed is maintained at 3600 rpm and the driving speed is 102 km/h ... At this time, the power performance of the Great Wall Gun off-road pickup truck is still abundant. Of course, by changing the speed and power, the instantaneous fuel consumption reaches 16 liters/100 kilometers.
The altitude rises gradually, and the outdoor temperature drops below zero. Due to the snowfall a few days ago, the road surface is covered with ice and snow. In the original normal mode, the car body frequently slips.
The TOD multi-disc clutch four-wheel drive system adapted to the cross-country version of Great Wall Gun is mainly driven by the rear wheel in SPORT\ECO\NORMAL mode for paving roads. When the front drive wheel slips, the clutch in the transfer case compresses multiple groups of clutch plates and connects the front drive shaft to transmit torque to the front drive axle.
In order to cope with the side slip caused by slippery snow and ice, the off-road pickup truck of Great Wall Gun switched to snow mode. After stepping on the accelerator pedal quickly and deeply, the torque output was limited by the engine control system, and the speed increased slowly, which has achieved a more stable driving posture. Starting from the snow mode, the shift control system locks the second gear instead of the 1 gear with faster torque release.
TOD multi-disc clutch four-wheel drive system provided by Borgwarner, which is mounted on the off-road pickup truck of Great Wall Gun, will actively distribute more torque to the front drive axle in ice and snow mode than in sports or normal mode.
On the ice and snow road at an altitude of 4340 meters, it is more dangerous to drive downhill than uphill. Select the manual shift mode, keep the engine speed at an appropriate 2500 rpm through forced shift, and gradually reduce the vehicle speed through torque suppression instead of passive deceleration through the brake system.
This 8AT system, which is suitable for the off-road pickup truck of Great Wall Gun, locks it into manual shift mode by pulling down the electronic shift lever twice in succession, instead of touching the steering wheel shift paddle for a short time in normal mode.
At present, the mainstream off-road vehicles sold in China mostly adopt time-sharing electronic four-wheel drive system and full-time four-wheel drive system. The time-sharing electronic four-wheel drive system is simple and reliable, but it can't be used on the road. Full-time four-wheel drive system is divided into mechanical control and electronic control, which can drive at a speed below 80 km/h on paved roads and complex roads. TOD multi-disc clutch four-wheel drive system is adopted in the off-road pickup truck of Great Wall Gun, which can drive continuously under different adhesion. Although it is not an electronic full-time four-wheel drive system, the electronic four-wheel drive system is more convenient to use. Of course, technical driving safety is not as effective as careful driving habits.
2. Reliability of power output at high altitude and high speed;
In Yushu, at an altitude of 4,400 meters, the Great Wall gun off-road pickup truck stood for a night for a "cold start" test, and the outdoor temperature dropped to-14 degrees Celsius the next morning. The welding surface temperature of the Great Wall gun off-road pickup truck body was measured by thermal imager, and the exposed skin surface temperature of colleagues dropped to a very low state.
The cross-country version of the Great Wall Gun, which stayed motionless all night, successfully "cold started" at-14 degrees Celsius. However, at the moment of pressing "one-button start", the speed of the starter is obviously "lengthened", and the idle speed of the engine is increased to 1200 rpm in the cold state.
Run for 3 minutes in the state of "cold car and high idle speed", and the engine speed will gradually drop to 800 rpm. At this time, after the cockpit air conditioning heating system is started to fully warm up the car, the engine and transmission will gradually enter the usable state. However, at this time, the grease temperature inside the front and rear drive axles and transfer gears of the Great Wall gun off-road pickup truck did not heat up rapidly, so it is recommended to drive at a low speed of 2 or 3 kilometers.
Out of professional habits, after the purchase and licensing procedures, the author removed the engine dust cover of this Great Wall gun off-road pickup truck. Removing the dust cover of the engine helps to dissipate heat in summer, but in cold winter, it will inadvertently become a place for some kittens to sleep, which will inevitably increase the chances of some cables being damaged.
From Beijing to Xining, the roads are paved, and the altitude is no more than 2000 meters. From Maduo via National Highway 365,438+07 to Jiuqi, almost all roads are slippery (paved) with ice and snow, and the altitude is maintained at 4000-5000 meters. High altitude climate and environment, long-term high-speed driving, this Great Wall gun off-road pickup truck carries 2.0T, numbered GW4C20B, with moderate water temperature and normal condition.
The above picture is a close-up of the technical status of the liquid replenishing pot and the upper cover of the main radiator of the Great Wall gun off-road pickup engine. The upper cover (indicated by red arrow) and the body (indicated by green arrow) of the rehydration kettle did not appear, and the cooling liquid did not have short-term pressure change and corrosion traces left by heating and baking.
Similarly, there is no corrosion white mark left on the interface between the upper cover of the main radiator and the fuselage when the coolant is pushed out by pressure and heated and baked.
The author has something to say:
First, the Great Wall gun off-road pickup truck made a targeted match for the trafficability of complex road conditions. The wading hose, steel front and rear bumpers to improve approach angle/departure angle, electric winch, external power supply and four sets of better protection plates basically save the cost of subsequent modification. Most importantly, as a "standard" accessory facility of the original factory, it can easily handle 1 vehicle inspection procedures every year.
With the maximum output of 140 kW and the maximum torque of 360 Nm, the coolant in the cooling pipe did not overflow under the high altitude climate environment and long-term frequent high-speed driving. It can be seen that the thermal management control efficiency of the engine based on the Great Wall gun off-road pickup truck is quite excellent.
After the in-depth experience of sports mode and snow mode, it is found that the Great Wall gun off-road pickup truck obtains different driving styles by "writing" different shift control strategies for 8AT, which reduces the driver's control difficulty and keeps the engine at different speed intervals to cope with different road conditions.
In particular, the all-electric steering gear of the off-road pickup truck of the Great Wall Gun is equipped with three feedback force adjustment control strategies. When driving in semi-road conditions, you can choose a state with less feedback, and gradually increase the feedback according to driving habits when driving or passing through complex road conditions.
As of press time, the total mileage of the Great Wall gun off-road pickup truck is 96 18km. Based on the TOD multi-disc clutch four-wheel drive system, the torque distribution performance of the front and rear drive axles on ice and snow roads and gravel roads will be mainly introduced in the article "Depth: Great Wall Gun Off-road pickup truck10.5 million kilometers".
To be continued. . . . .
Produced by evaluation group of new energy information analysis network
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.
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