idle warm-up experiment

[Compaq888]

Originally Posted by JanGeo

Yup the math is correct and the inverter is going to add some losses You should look at the temperature rise as a function of time like the idle test you did to see what gives the most increase per watt hour of energy by the heater. This will give you the rate of heat loss of the engine. Maybe you could run a bunch of smaller 12 volt batteries in series instead of the inverter and get a little less voltage and watts into the heater but still have it help. Now you are starting to see the power of gasoline vs electricity. Anyone for an engine blanket??? Maybe a fully insulated engine compartment. Another idea would be an insulated tank with extra coolant that you heat up while driving then with a valve seal off from the motor. When you get back in the car you dump the still hot water back into the motor an poof instant heat. No extra energy used and if you want use the block heater on the insulated tank. Man what a great idea huh? Only would take a few gallons of storage - a small hot water heater would work.

The prius already has this system in use. It keeps the coolant warm up to 3 days.

[MetroMPG]

since initially doing the idle warm-up experiment, i kicked myself for not recording the fuel consumption data in the few first minutes.

<a href="http://www.gassavers.org/forum_topic/idle.html">sludgy's thread</a> today about his idle gallon-per-hour observations (he got a scangauge - new toy!) inspired me to complete the test.

as it turned out, tonight was the same temperature as the original test, so i only reproduced the first 3 minutes, and have added that data to complete the table and chart.

<b>the finished table:</b>

<TABLE CELLSPACING="0" BORDER="1" CELLPADDING="2"><TR><TD><B>time (min)</B></TD><TD><B>FWT</B></TD><TD><B>FIA</B></TD><TD><B>Lph</B></TD></TR><TR><TD>0</TD><TD>19</TD><TD>22</TD><TD>1.5</TD></TR><TR><TD><P></P></TD><TD>30</TD><TD>19</TD><TD>1.3</TD></TR><TR><TD>1</TD><TD>42</TD><TD>21</TD><TD>1.1</TD></TR><TR><TD><P></P></TD><TD>57</TD><TD>21</TD><TD>1.0</TD></TR><TR><TD>2</TD><TD>73</TD><TD>21</TD><TD>1.0</TD></TR><TR><TD><P></P></TD><TD>83</TD><TD>21</TD><TD>0.9</TD></TR><TR><TD>3</TD><TD>96</TD><TD>22</TD><TD>0.8</TD></TR><TR><TD><P></P></TD><TD>105</TD><TD>24</TD><TD>0.8</TD></TR><TR><TD>4</TD><TD>110</TD><TD>24</TD><TD>0.7</TD></TR><TR><TD><P></P></TD><TD>118</TD><TD>26</TD><TD>0.7</TD></TR><TR><TD>5</TD><TD>127</TD><TD>28</TD><TD>0.7</TD></TR><TR><TD><P></P></TD><TD>132</TD><TD>30</TD><TD>0.7</TD></TR><TR><TD>6</TD><TD>137</TD><TD>30</TD><TD>0.7</TD></TR><TR><TD><P></P></TD><TD>141</TD><TD>30</TD><TD>0.7</TD></TR><TR><TD>7</TD><TD>146</TD><TD>31</TD><TD>0.6</TD></TR><TR><TD><P></P></TD><TD>150</TD><TD>33</TD><TD>0.6</TD></TR><TR><TD>8</TD><TD>154</TD><TD>35</TD><TD>0.6</TD></TR><TR><TD><P></P></TD><TD>157</TD><TD>37</TD><TD>0.6</TD></TR><TR><TD>9</TD><TD>161</TD><TD>37</TD><TD>0.6</TD></TR><TR><TD><P></P></TD><TD>164</TD><TD>37</TD><TD>0.6</TD></TR><TR><TD>10</TD><TD>166</TD><TD>40</TD><TD>0.6</TD></TR><TR><TD><P></P></TD><TD>168</TD><TD>42</TD><TD>0.6</TD></TR><TR><TD>11</TD><TD>172</TD><TD>42</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>173</TD><TD>46</TD><TD>0.5</TD></TR><TR><TD>12</TD><TD>175</TD><TD>46</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>179</TD><TD>48</TD><TD>0.5</TD></TR><TR><TD>13</TD><TD>181</TD><TD>48</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>182</TD><TD>51</TD><TD>0.5</TD></TR><TR><TD>14</TD><TD>184</TD><TD>51</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>186</TD><TD>51</TD><TD>0.5</TD></TR><TR><TD>15</TD><TD>188</TD><TD>53</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>190</TD><TD>55</TD><TD>0.5</TD></TR><TR><TD>16</TD><TD>191</TD><TD>55</TD><TD>0.5</TD></TR><TR><TD><P></P></TD><TD>193</TD><TD>57</TD><TD>0.5</TD></TR><TR><TD>17</TD><TD>195</TD><TD>57</TD><TD>0.5</TD></TR></TABLE>

<b>the finished chart:</b>

<img src="http://metrompg.com/offsite/warm-up-chart-complete.gif">

<b>the verdict:</b>

man, i hate doing these fuel-wasting experiments! :\

[Matt Timion]

Just for reference:

FWT: coolant (water) temp in degrees F
FIA: intake air temp in degrees F
Lph: fuel consumption in liters per hour

[krousdb]

Evidently I missed this thread. Great info, let me add some more. My OEM EBH cost was $42. It installs in the fromt engine block drain plug and yeah, its a PITA to get out. It is marked 400W, but my kill-o-watt mater says 375W.

I did some testing to determine how long I should set the timer prior to leaving in the morning. After about 8 hours, the ECT was 60F above ambient. But it only takes one hour to get 35F and two hours to get 45F over ambient. In the winter my garage is usually 45F so 80F is my usual staring temp. The extra 10F wasn't worth another 3.75 cents IMO. I am impressed with the performance and am glad I installed it.

I have tried two other types of EBH. The magnetic oil pan heater is rated at 200W, actual 180W. I would use this to heat the engine oil but it is thermostatically controlled and it shuts down only after a minute or two. Not sure if it is a malfunction or not, but it has little effect on the temperature of the oil pan as reported by my IR thermometer.

The second type is the recirculating EBH, 850W rated, 750W actual. For these to function correctly you need to have a hose that comes from the bottom of the EB and into the top of the EB. I don't have such an arrangement so I installed it in my heater hose line, the only place available. In that configuration it did nothing but heat the water in the hose, no circulation. Be aware that there isn't a pump in these, they rely on convective flow which reguires the hose configuration previously mentioned. If you dont have that config, IMO you are better off with the drain plug type.

[Compaq888]

What about having something like the prius. It has a system where you shut off the car and the fluid goes into a special container and stays warm in there up to 3 days. I already mentioned this and nobody payed attention.

[krousdb]

Originally Posted by Compaq888

What about having something like the prius. It has a system where you shut off the car and the fluid goes into a special container and stays warm in there up to 3 days. I already mentioned this and nobody payed attention.

There would be a great deal of expense involved with a system like that. Sure you could find one in the junk yard but where will you put it and how will you connect to the coolant system? How will you activate it? I don't have room under my hood for the thermos and no room in the wheel well either.

As far as keeping warm for 3 days, well I guess warm is a relative term. The next morning, depending on the temperature of the garage, when first powering up, the coolant temp is 110 - 130F. But drops down to 90-110F very shortly as the aluminum block and head pull warmth from the coolant. So what you end up with after about 12 hours parked in the garage is about 100F on average or in my case, 55F above ambient. I can be at 100F after 2.5 hours with the OEM EBH at a cost of under 10 cents. For 3 cents I can be at 80F. I doubt that there would be significant fuel savings between 80F and 100F starting temps.

The same would apply to non garage kept vehicles except the amb ient temp would be lower so the thermos protected coolant would be cooler, the block and head would be cooler, which would lower the ECT further.

IMHO, the OEM EBH is cheaper, easier to install, easier to maintain and nearly as effective as a Prius type thermos.

[MetroMPG]

Originally Posted by krousdb

For 3 cents I can be at 80F. I doubt that there would be significant fuel savings between 80F and 100F starting temps.

good EBH info, krousdb.

should i take your comment to mean you won't be plugging in year-round?

[MetroMPG]

Originally Posted by Compaq888

I already mentioned this and nobody payed attention.

i don't think anyone was ignoring your comment. fyi, the coolant thermos topic was in this thread too:

http://www.gassavers.org/forum_topic/engine_block_heater_success.html

[Matt Timion]

Originally Posted by MetroMPG

i don't think anyone was ignoring your comment. fyi, the coolant thermos topic was in this thread too:

http://www.gassavers.org/forum_topic/engine_block_heater_success.html

THis is why no one responded to you Compaq888. It was previously mentioned that exact same day by someone else. When you mentioned it I was unsure if you had not read the other thread or not.

[krousdb]

Originally Posted by MetroMPG

good EBH info, krousdb.

should i take your comment to mean you won't be plugging in year-round?

For 3 cents a day I can raise the ECT 35F over ambient. So in the summer, when my garage is 80F overnight, I will be at 115F for 3 cents. And that doesn't take into account the smaller delta between ECT temp at shutdown and garage temp in the summer. The ECT will go down much slower overnight so it may be above the garage temp the next morning. So yes, I think it will be worth it to plug in year round.


What I meant to say is that it didn't make sense (cents) to spend twice as much on electricity for only 10F higher on the ECT because of the diminishing return.