Winter cold start & idling warm-up experiment

[Weather Spotter]

I see more data for the wiki coming

Long time without adding data, I am hungry for new data!

[abently]

Have you guys considered modifying the Coolant temp sensor with a resistor to reduce 'Cold-start fuel enrichment'?

I doubt you could get away with what I did, by skewing it so much that fuel-enrichment is non-existent, and gaining 7% overall but I'm sure you could still enjoy 'Fuel-enrichment' smoothness by adding 60F to the minimum temp you see.

I picked 60F assuming you get 0F, which means it will think its 15deg Celsius and therefore still apply enough enrichment.

The resistor in parallel works best if the Coolant temp sensor resistance drops with increasing temperature, so that even though you have altered the value at low temperatures by a lot, it only changes it by a little at the operating temperature.

I can throw up a spreadsheet if people want to have a looksie and modify it for their own use.

[dennyt]

I just did this over the weekend, with a 100k stereo potentiometer mounted in the dash. All the way left (low-volume...) is essentially stock, and about 1/3 of the range gets me as lean as I want to go for now.

Next up is a heated O2 sensor, I noticed my car going into closed-loop mode very quickly, but the idle was bouncing all over the place.

I really like having more control over the warmup enrichment!

[redyaris]

In my Yaris I have a warm air intake and upper grill blocker and at -5C ambient air temperatue it gets to 55C coolant temperature in less than 2km at speed of less than 70km/hr. this takes less than 3 minutes. it takes an other 5 too 10 minutes to get to 85C operating temperature.

[Piwoslaw]

Originally Posted by MetroMPG

I'm betting your engine warms up faster. Based on nothing

Originally Posted by Daox

I bet its slower, based on it being diesel.

And the winner is... Daox!!

Now the next question is: When does my 1.6 liter turbodiesel get up to operating temperature?

The find out the answer you'll have to read on :evil_smirk:

So today I found some time to do the idling test. When I started at noon it was sunny and a toasty -12°C (10°F) outside. Starting the cold soaked engine wasn't easy, especially when the battery is 5.5 years old and the glow plugs are acting up.

As mentioned earlier, I took notes every 30 seconds, writing down the intake air temperature, water temperature, fuel consumption and total fuel used. After the first few minutes I knew I was going to spend more time on this than 17 minutes. In fact, I spent more than twice that (35 minutes), and my coolant just barely got to 66°C (151°F). My normal operating temperature is 78°C (172°F). I wasted almost half a liter of diesel fuel. I could have kept it going indefinitely and the thermostat probably wouldn't open until April (starts to open around 83°C/181°F).

The experinment was done without my temporary thermal insulation, and with everything switch off. Here is the data:

time (minutes)	Intake air temperature (°C)	Water temperature (°C)	Fuel consumption (liters per hour)	Total fuel used (liters, diesel)
0	-12	-12	1.20	0.00
0.5	-11	-10	0.94	0.00
1	-11	-7	0.95	0.01
1.5	-11	-4	0.96	0.02
2	-11	0	1.05	0.03
2.5	-10	3	1.04	0.04
3	-10	6	1.02	0.05
3.5	-10	9	0.93	0.05
4	-10	11	0.91	0.06
4.5	-9	13	1.05	0.07
5	-9	14	1.02	0.08
5.5	-9	16	1.02	0.09
6	-8	18	0.98	0.10
6.5	-8	20	0.99	0.10
7	-8	21	0.96	0.11
7.5	-7	23	0.97	0.12
8	-7	24	1.00	0.13
8.5	-7	26	0.97	0.14
9	-6	27	0.94	0.14
9.5	-6	28	0.95	0.15
10	-6	29	0.78	0.16
10.5	-5	31	0.80	0.17
11	-5	32	0.80	0.17
11.5	-4	33	0.78	0.18
12	-4	34	0.78	0.19
12.5	-4	35	0.77	0.19
13	-3	36	0.75	0.20
13.5	-3	37	0.76	0.21
14	-3	38	0.76	0.21
14.5	-2	39	0.75	0.22
15	-2	40	0.75	0.22
15.5	-1	41	0.72	0.23
16	-1	42	0.73	0.24
16.5	-1	42	0.73	0.24
17	0	43	0.73	0.25
17.5	0	44	0.74	0.25
18	0	45	0.74	0.26
18.5	1	46	0.72	0.27
19	1	46	0.70	0.27
19.5	2	47	0.70	0.28
20	2	48	0.69	0.28
20.5	2	49	0.69	0.29
21	3	49	0.69	0.30
21.5	3	50	0.67	0.30
22	3	51	0.67	0.31
22.5	4	52	0.67	0.31
23	4	52	0.67	0.32
23.5	5	53	0.66	0.32
24	5	54	0.66	0.33
24.5	5	54	0.65	0.33
25	6	55	0.64	0.34
25.5	6	56	0.65	0.35
26	7	56	0.68	0.35
26.5	7	57	0.68	0.36
27	7	57	0.66	0.36
27.5	8	58	0.66	0.37
28	8	58	0.68	0.37
28.5	8	59	0.68	0.38
29	9	59	0.68	0.38
29.5	9	60	0.67	0.39
30	9	60	0.67	0.40
30.5	10	61	0.67	0.40
31	10	61	0.66	0.41
31.5	11	62	0.65	0.41
32	11	63	0.65	0.42
32.5	11	63	0.65	0.42
33	11	64	0.64	0.43
33.5	12	64	0.63	0.43
34	12	65	0.63	0.44
34.5	12	65	0.62	0.44
35	13	66	0.62	0.45

After the test was finished I turned the heat and blower on and set them to max, and the coolant temperature instantly dropped 10 degrees to 55°C (131°F). I then drove 2km to the vet (with the heat on) and the coolant temperature never rose above 55°C.

Now that I have data from both this and the coolant heater experiment I'll crunch some numbers and see how to use the heater most efficiently.

[slogfilet]

Originally Posted by abently

Have you guys considered modifying the Coolant temp sensor with a resistor to reduce 'Cold-start fuel enrichment'?

I can throw up a spreadsheet if people want to have a looksie and modify it for their own use.

I would be interested in this idea... maybe a new thread? It would be a good place for mods like that and some info about open vs closed loop.

[MetroMPG]

Originally Posted by Piwoslaw

And the winner is... Daox!!

In my defense! I wasn't sure what would win the tug-of-war between the 993cc Suzuki and your 1.6D: the advantage of diesel efficiency, or the penalty of the larger engine.

Now we know!

I could have kept it going indefinitely and the thermostat probably wouldn't open until April

Thanks for the laugh!

[Piwoslaw]

Originally Posted by MetroMPG

In my defense! I wasn't sure what would win the tug-of-war between the 993cc Suzuki and your 1.6D: the advantage of diesel efficiency, or the penalty of the larger engine.

Now we know!

Actually, I personally thought my time would be closer to your's. I doubted it would be less than 20 minutes, but I had no idea that after over half an hour it wouldn't even get near operating temperature. Yes, it was 5 degrees C colder than in your test, but after 17 minutes your engine was 98°C over abmient, while mine was only 55°C over

Diesel efficiency or not, this tank ain't gonna break no records All in the name of science, they say...