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Power Shortage And Fuel Consumption Of Atypical A7 Fault Cases

A7 has been born for 2 years. So far, it has not passed the swaddling period, and it is a swaddling period with poor “environment”. Looking at the use of many A7 users on the forum, we also talked about some “small problems” of A7 in the past few days. A friend on the forum bought A7 because he didn’t like buying a car. He just liked AMT. When he bought it, he found that this baby is very hot. Fortunately, he has been running in Shanghai and Shandong recently, so we also had the opportunity to get in close contact of A7 fault cases:

“Preliminary inspection and hidden danger elimination of A7 initial experience” by forum member “looking 2009”. I didn’t elaborate on many small problems at the beginning of collecting the car, Relevant components of ASR system were assembled with the strong assistance of Mr. Zhang Jixin of Shanghai (I’ve wiped my butt), but the fuel consumption of this vehicle is still high. At the speed of 90-105km / h, the fuel consumption has been approaching the 60L mark. However, during the inspection, it was found that the compensation value of the fuel injectors of several cylinders was a little high at idle speed, and the sound change from the external speed of the engine during the cylinder breaking test was not obvious. Because all the inspection items were inspected, the supercharger The valve stem of the pressure relief valve may not move freely due to the high temperature after painting. This problem has been solved by the owner, but the fuel consumption has been partially improved, but the power is still insufficient of A7 fault cases.

On August 28, I was very excited to arrive at a service station close to home, I saw A7 in looking2009 and knew him for nearly a year (the first time we met), I happened to meet Mr. Jiang, an application engineer in charge of heavy truck at WABCO. It seems that I have come for a consultation. The young man at the service station is very efficient. When I arrived, I had removed the valve cover of the engine. After the old-fashioned cylinder breaking test of the unsuitable diagnostic instrument, I still found that at least one cylinder does not inject fuel, and one cylinder seems to spray but not spray. I can’t say anything Say, change.

In the gap between replacing the fuel injector and Xiaoqu (looking2009), I talked about some problems in use. In order to better protect the low-pressure oil circuit and various components on the high-pressure oil circuit, Xiaoqu went to Beijing and bought back Parker’s fh1000 electrically heated fuel primary filter (including oil-water separator).

After looking at the lower filter cup, Xiaoqu said sadly, look, this is the oil added in the service area near the coast of Shandong! After wiping the outer surface, there are many impurities and flocculent sediments inside. Hey, when can China’s oil products really go to Europe 3? 2014.

Check the gap between the and look at the lower inlet of A7. Eh, No, I remember that there is a metal mesh dust cover (preventing large objects from entering) in this place of FH16 series. Why A7 doesn’t have it (click to view the FH16 dust cover setting)? What do you want these small support strips to do? Moreover, there is a “big hole” in the dust collector below, which seems to be afraid that it can’t be opened. People open the seam directly. See, you still say no!

After replacing the fuel injector and starting the test run, the sound of D12 has actually completely abandoned the clattering characteristics of WD615 teacher’s engine and turned into a low and roaring feeling; For Xiaoqu’s OD, Mr. Jiang specially checked some parameters related to his gearbox with the diagnostic system. Everything is normal, which means that the problem I judged last time is likely to be established (see the blog about AMT that needs to be improved). I hope the 35th version of AMT software can give Xiaoqu a new understanding of AMT.

Well, I’ll wait for his reply in A7 use. Take a group photo before leaving. I’m fat. It really takes up space.

These days in early September, Xiaoqu went through two long journeys. At present, his feedback information still has some small problems, such as fuel consumption. At present, the standard load speed is about 90 and the fuel consumption is 43; In view of this situation, let’s make a relatively rational analysis:

Through the speed calculator of truck house, you can get the corresponding engine speed of his running speed, which is about 1500-1550.

That is, if we look at D12 For the universal characteristic curve of the high-speed version of the 380 engine, according to some characteristics of the A7, calculate the constant speed fuel consumption of his car with a relatively simple fuel consumption calculation formula that is not very complex:

The error between this calculated value and his current actual test value is basically not very large (in ideal state). Because of the configuration relationship of d12.380 + 16od + 3.93, we suggest him to conduct an experiment on a flat road under standard load and at a speed of 80km / h when the engine is running at 1300 rpm.

According to some existing problems of Xiaoqu’s vehicles, I personally think that if sinotruk wants to really improve the market share of tractors, it should also do pre-sales service training for users on the basis of strengthening the seller’s understanding and training of products; At the same time, since there are more or less problems in the use of AMT, especially overdrive gearbox in the past six months, it is suggested that sinotruk cooperate with WABCO company to make corrections and improvements in time. As for some problems of common rail engine, this is not only heavy truck, but also all domestic car factories have more or less deficiencies in this aspect. This is not only the problem of products, but also the problem of oil products in our country, as well as some understanding problems of our users.

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